U.S. patent application number 12/362533 was filed with the patent office on 2010-08-05 for templated catalyst composition and associated method.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Dan Hancu, Larry Neil Lewis, Oltea Puica Siclovan, Ming Yin.
Application Number | 20100196237 12/362533 |
Document ID | / |
Family ID | 42397889 |
Filed Date | 2010-08-05 |
United States Patent
Application |
20100196237 |
Kind Code |
A1 |
Yin; Ming ; et al. |
August 5, 2010 |
TEMPLATED CATALYST COMPOSITION AND ASSOCIATED METHOD
Abstract
A composition includes a templated metal oxide, at least 3
weight percent of silver, and at least one catalytic metal. A
method of making and a method of using are included.
Inventors: |
Yin; Ming; (Schenectady,
NY) ; Lewis; Larry Neil; (Scotia, NY) ; Hancu;
Dan; (Clifton Park, NY) ; Siclovan; Oltea Puica;
(Rexford, NY) |
Correspondence
Address: |
GENERAL ELECTRIC COMPANY;GLOBAL RESEARCH
ONE RESEARCH CIRCLE, BLDG. K1-3A59
NISKAYUNA
NY
12309
US
|
Assignee: |
GENERAL ELECTRIC COMPANY
SCHENECTADY
NY
|
Family ID: |
42397889 |
Appl. No.: |
12/362533 |
Filed: |
January 30, 2009 |
Current U.S.
Class: |
423/239.1 ;
502/243; 502/317; 502/330; 502/343; 502/347; 502/348 |
Current CPC
Class: |
B01D 53/9418 20130101;
B01J 23/002 20130101; B01J 23/50 20130101; B01J 35/04 20130101;
B01J 21/04 20130101; B01J 2523/00 20130101; B01D 2255/104 20130101;
B01D 53/8628 20130101; B01D 2255/2092 20130101; B01J 2523/31
20130101; B01J 2523/27 20130101; B01J 2523/31 20130101; B01J
2523/31 20130101; B01J 2523/31 20130101; B01J 2523/69 20130101;
B01J 2523/18 20130101; B01J 2523/18 20130101; B01J 2523/18
20130101; B01J 2523/48 20130101; B01J 2523/33 20130101; B01J
2523/32 20130101; B01J 2523/18 20130101; B01J 2523/31 20130101;
B01J 2523/822 20130101; B01J 2523/18 20130101; B01J 2523/00
20130101; B01J 2523/00 20130101; B01D 2255/90 20130101; B01J 35/002
20130101; B01J 23/60 20130101; B01J 2523/00 20130101; B01D
2255/1021 20130101; B01J 2523/00 20130101; B01J 2523/31 20130101;
B01J 2523/842 20130101; B01J 2523/18 20130101; B01J 35/1004
20130101; B01J 2523/00 20130101; B01J 2523/00 20130101; B01J 23/687
20130101; B01D 2255/1025 20130101; B01J 37/031 20130101 |
Class at
Publication: |
423/239.1 ;
502/347; 502/348; 502/243; 502/330; 502/317; 502/343 |
International
Class: |
B01D 53/86 20060101
B01D053/86; B01J 23/50 20060101 B01J023/50; B01J 21/04 20060101
B01J021/04; B01J 21/12 20060101 B01J021/12; B01J 23/745 20060101
B01J023/745; B01J 23/68 20060101 B01J023/68; B01J 23/06 20060101
B01J023/06; B01D 53/56 20060101 B01D053/56 |
Claims
1. A composition, comprising: a templated metal oxide substrate
material having a plurality of pores; and a catalyst material
comprising a catalyst metal and silver; and the silver is present
in an amount of at least about three weight percent based on a
total weight of the substrate material.
2. The composition as defined in claim 1, wherein the templated
metal oxide is alumina or silica-alumina.
3. The composition as defined in claim 1, wherein the templated
metal oxide has periodically arranged templated pores, wherein the
average diameter of the pores is in a range of from about 2
nanometers to about 100 nanometers and the pores have a periodicity
in a range of from about 50 Angstrom to about 130 Angstrom.
4. The composition as defined in claim 1, wherein the templated
metal oxide has a surface area greater than about 0.5
meter.sup.2/gram; wherein the templated metal oxide is present in
an amount greater than about 50 mole percent of the composition; or
wherein the silver is present in an amount of less than or equal to
ten weight percent of a total weight of the substrate material.
5. The composition as defined in claim 1, wherein the catalyst
metal comprises one or more material selected from group consisting
of zirconium, iron, gallium, indium, tungsten, zinc, platinum, and
rhodium.
6. The composition as defined in claim 5, wherein the catalyst
metal is zirconium.
7. The composition as defined in claim 5, wherein the catalyst
metal comprises iron.
8. The composition as defined in claim 5, wherein the catalyst
metal comprises gallium, indium, or both gallium and indium.
9. The composition as defined in claim 8, wherein the catalyst
metal comprises both gallium and indium, and they are present in a
ratio such that gallium is present more than 2:1 relative to
indium.
10. The composition as defined in claim 5, wherein the catalyst
metal is tungsten.
11. The composition as defined in claim 5, wherein the catalyst
metal is zinc.
12. The composition as defined in claim 5, wherein the catalyst
metal is platinum.
13. The composition as defined in claim 5, wherein the catalyst
metal is rhodium.
14. The composition as defined in claim 5, wherein the catalyst
metal comprises an oxide.
15. The composition as defined in claim 1, wherein the catalyst
metal is present in an amount in a range of from about 0.1 weight
percent to about 3 weight percent, based on the total weight of the
composition.
16. The composition as defined in claim 1, wherein the composition
is free of alkaline earth metal.
17. The composition as defined in claim 1, wherein the composition
is capable of reducing NOx in reactive proximity therewith without
absorbing the NOx on a catalyst material surface.
18. The composition as defined in claim 1, wherein the composition
has capability of reducing nitrogen oxide greater than 40 percent
by volume at a temperature of about 325 degrees Celsius.
19. A method, comprising: introducing a gas stream in a chamber
that includes the composition as defined in claim 1; and reducing
nitrogen oxide present in the gas stream at a temperature that is
greater than about 275 degrees Celsius.
20. The method as defined in claim 19, wherein the reducing
nitrogen oxide comprises maintaining a temperature in the chamber
that is greater than about 275 degrees Celsius and that is less
than about 325 degrees Celsius.
21. A method, comprising: reacting a metal alkoxide, a silver
composition, a catalyst metal composition and a templating agent to
form a reaction product; hydrolyzing the reaction product to form a
hydrolyzed reaction product; condensing the hydrolysed reaction
product to form a templated substrate; and controlling the
reacting, hydrolysing and condensing step to control the silver
loading of the templated substrate.
22. The method as defined in claim 21, controlling the silver
loading so that the silver is present in an amount of at least
about three weight percent based on a total weight of the material
that is the templated substrate.
23. The method as defined in claim 21, wherein the condensing step
includes calcinating.
24. The method as defined in claim 21, wherein the hydrolyzing step
comprises hydrolyzing the reaction product over a period that is
greater than about 1 hour.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The invention includes embodiments that relate to a catalyst
composition. The invention includes embodiments that relate to a
method of making the catalyst composition and a method of using the
catalyst composition for reducing nitrogen oxides.
[0003] 2. Discussion of Art
[0004] Currently, lean NOx traps may be used in exhaust gas
treatment systems. In these, NOx reduction catalysts and methods
include the alkali and alkali earth metal in the catalyst
composition where the alkali metal or the alkali metal absorbs the
NOx and the reductant reduces NOx to nitrogen. This type of
reaction may not have desirable kinetics.
[0005] Silver-containing alumina is known for selective catalytic
reduction (SCR) of NOx using linear hydrocarbon reductants.
However, reductants containing aromatics like those present in
Diesel fuel, lead to poor NOx reduction with concomitant carbon
deposition.
[0006] Therefore, it may be desirable to have a catalyst
composition with properties and characteristics that differ from
those properties of currently available compositions or catalysts.
It may be desirable to have a method that differs from those
methods currently available.
BRIEF DESCRIPTION
[0007] In one embodiment, a composition includes a templated metal
oxide substrate having a plurality of pores and a catalyst
material. The catalyst material includes silver and a catalyst
metal. The silver is present in an amount that is at least about
three weight percent based on a total weight of the substrate.
[0008] In one embodiment, a method of using the said catalyst
composition is by introducing a gas stream in a chamber having a
composition including a templated metal oxide substrate having a
plurality of pores, a catalyst material includes silver and a
catalyst metal. The silver is present in an amount of at least
about three weight percent based on a total weight of the
substrate. The nitrogen oxide present in the gas stream is reduced
at a temperature in the range from about 275 degrees to about 350
degrees Celsius in the chamber.
BRIEF DESCRIPTION OF DRAWINGS
[0009] FIG. 1 is a graph of low angle X-Ray Diffraction (XRD)
scan;
[0010] FIG. 2 is an image of scanning electron microscope (SEM) for
Ag-Templated Alumina;
[0011] FIG. 3 is an image of scanning electron microscope (SEM) for
SBA alumina 200 from SASOL;
[0012] FIG. 4 is an image of scanning electron microscope (SEM) for
Norton Alumina;
[0013] FIG. 5 is a visible-ultra-violet spectrum of a catalytic
material;
[0014] FIG. 6 is a visible-ultra-violet spectrum of a catalytic
material;
[0015] FIGS. 7 and 8 are graphical representations of NOx
conversion;
[0016] FIGS. 9 and 10 are graphical representations of NOx
conversion;
[0017] FIGS. 11 and 12 are graphical representations of NOx
conversion;
[0018] FIGS. 13 and 14 are graphical representations of NOx
conversion;
[0019] FIGS. 15 and 16 are graphical representations of NOx
conversion;
[0020] FIGS. 17 and 18 are graphical representations of NOx
conversion;
[0021] FIG. 19 is a graphical representation of NOx conversion;
[0022] FIG. 20 is a graphical representation of NOx conversion;
and
[0023] FIG. 21 is a graphical representation of NOx conversion.
DETAILED DESCRIPTION
[0024] The systems and methods described herein include embodiments
that relate to a catalyst composition, embodiments that relate to a
method of making the catalyst composition, and a method of using
the catalyst composition for reducing nitrogen oxides. Generally,
disclosed is a NOx reduction catalyst and NOx reduction system for
reducing NOx in exhaust gas discharged from a combustion device.
Suitable combustion devices may include furnaces, ovens or
engines.
[0025] As used herein, a catalyst is a substance that can cause a
change in the rate of a chemical reaction without itself being
consumed in the reaction. A slurry is a mixture of a liquid and
finely divided particles. A sol is a colloidal solution. A powder
is a substance including finely dispersed solid particles.
Templating refers to a controlled patterning; and, templated refers
to determined control of an imposed pattern and may include
molecular self-assembly. A monolith may be a ceramic block having a
number of channels, and may be made by extrusion of clay, binders
and additives that are pushed through a dye to create a structure.
Approximating language, as used herein throughout the specification
and claims, may be applied to modify any quantitative
representation that could permissibly vary without resulting in a
change in the basic function to which it is related. Accordingly, a
value modified by a term such as "about" is not to be limited to
the precise value specified. In some instances, the approximating
language may correspond to the precision of an instrument for
measuring the value. Similarly, "free" may be used in combination
with a term, and may include an insubstantial number, or trace
amounts, while still being considered free of the modified
term.
[0026] In one embodiment, the composition includes a templated
metal oxide substrate having a plurality of pores, and a catalyst
material includes both silver and a catalyst metal. The silver is
present in an amount that is at least about three weight percent
based on a total weight of the substrate.
[0027] In addition to being templated, the substrate may have a
macro-shape that is, for example, a ceramic honeycomb. With regard
to the templating, the substrate material may have a plurality of
pores that may have specific dimensions and periodicity. That is,
the templated metal oxide may have periodically arranged templated
pores of determined dimensions. The dimensions can include pore
diameter, degrees of curvature, uniformity of the inner surface,
and the like. The average diameter of the pores may be greater than
about 2 nanometers. The average diameter of the pores may be less
than about 100 nanometers. The average diameter of the pores may be
in a range from about 2 nanometers to about 20 nanometers, from
about 20 nanometers to about 40 nanometers, from about 40
nanometers to about 60 nanometers, from about 60 nanometers to
about 80 nanometers, or from about 80 nanometers to about 100
nanometers. The pores may have a periodicity greater than about 50
Angstroms. The pores may have a periodicity less than about 130
Angstroms. The pores may have a periodicity in the range of from
about 50 Angstroms to about 80 Angstroms, from about 80 Angstroms
to about 100 Angstroms, from about 100 Angstroms to about 120
Angstroms, or from about 120 Angstroms to about 150 Angstroms. Low
angle XRD, FIG. 1, for Ag-Templated Alumina comprising 3 percent or
5 percent silver prepared via sol gel or incipient wetness (IW)
method. All samples calcinated at 600 degrees Celsius, show that
Ag-Templated Alumina (TA) has pore dimensions of from 75-95
Angstroms depending on the method of preparation. FIG. 1 shows
graph 10 that has peak 12 that denotes the average pore-to-pore
correlation of about 75 Angstroms and peak 14 denotes the average
pore-to-pore correlation of about 95 Angstroms. In one embodiment,
the addition of a catalyst metal to the silver does not affect the
properties of the templated metal oxide substrate.
[0028] The templated porous metal oxide substrate may have a
surface area that is greater than about 0.5 meter.sup.2/gram. In
one embodiment, the surface area is in a range of from about 0.5
meter.sup.2/gram to about 10 meter.sup.2/gram, from about 10
meter.sup.2/gram to about 100 meter.sup.2/gram, from about 100
meter.sup.2/gram to about 200 meter.sup.2/gram, or from about 200
meter.sup.2/gram to about 1200 meter.sup.2/gram. In one embodiment,
the porous substrate has a surface area that is in a range of from
about 0.5 meter.sup.2/gram to about 200 meter.sup.2/gram. In one
embodiment, the porous substrate has a surface area in a range of
from about 200 meter.sup.2/gram to about 250 meter.sup.2/gm, from
about 250 meter.sup.2/gram to about 500 meter.sup.2/gm, from about
500 meter.sup.2/gram to about 750 meter.sup.2/gm, from about 750
meter.sup.2/gram to about 1000 meter.sup.2/gm, from about 1000
meter.sup.2/gram to about 1250 meter.sup.2/gm, from about 1250
meter.sup.2/gram to about 1500 meter.sup.2/gm, from about 1500
meter.sup.2/gram to about 1750 meter.sup.2/gm, from about 1750
meter.sup.2/gram to about 2000 meter 2/gm, or greater than about
2000 meter.sup.2/gm.
[0029] SEM analysis of Ag-Templated Alumina (TA), FIG. 2, appears
to show the high surface area and may show the pore structure. The
SEM picture in FIG. 2 is contrasted in FIG. 3 for SBA 200 alumina
with lower surface area and lower activity than Ag-TA and similarly
for Norton alumina in FIG. 4.
[0030] The templated porous metal oxide substrate may be present in
the catalyst composition in an amount that is greater than about 50
mole percent. In one embodiment, the amount of templated metal
oxide substrate may be in a range of from about 50 mole percent to
about 60 mole percent, from about 60 mole percent to about 70 mole
percent, from about 70 mole percent to about 80 mole percent, from
about 80 mole percent to about 90 mole percent, from about 90 mole
percent to about 95 mole percent, from about 95 mole percent to
about 98 mole percent, based on the total weight of the catalyst
composition.
[0031] In one embodiment, the metal oxide is an aluminum oxide.
Other support materials may be suitable. These other support
materials may include one or more of silicon, titanium or
zirconium. Suitable support materials may include, for example,
aluminosilicates, aluminophosphates, hexaaluminates, zirconates,
titanosilicates, titanates, or a combination of two or more
thereof. In other embodiments, other substrates or support
materials may be suitable and can be selected based on end-use
parameters.
[0032] The composition may also have a promoter for the catalytic
reaction of nitrogen oxide reduction. Non-limiting examples of the
catalyst may include various metals or metal oxides. The promoter
may include one or more of indium, gallium, tin, silver, manganese,
molybdenum, chromium, germanium, cobalt, nickel, gold, copper,
iron, and their oxides. In one embodiment, the promoter includes
silver.
[0033] In one embodiment, the catalyst material is free of one or
both of alkali metal and alkaline earth metal. In one embodiment,
the composition reduces NOx without absorbing the NOx on the
catalyst material. In this embodiment, the catalytic action is
distinct from the actions of a lean NOx trap.
[0034] In one embodiment, the catalyst composition may be made by
reacting a metal alkoxide with a silver composition, a catalyst
metal and a templating agent to form a reaction product. The
templating agent may be a surfactant, a cyclodextrin, a crown
ether, or mixtures thereof.
[0035] The reaction product may hydrolyze to form a hydrolyzed
reaction product. The hydrolyzed reaction product may condense to
form a templated substrate. The catalyst material loading of the
templated substrate may be controlled by controlling the reacting,
hydrolyzing and condensing steps. With particular reference to the
hydrolyzing step, the rate of hydrolysis can be controlled to
affect the reaction product properties, efficacy and function.
While completion of the hydrolysis process is a goal, the process
by which the hydrolysis is accomplished may be a factor in the
reaction product properties, efficacy and function. Slowing the
addition rate, and therefore the rate at which the hydrolysis can
proceed to completion, is one way to control the final result.
While it may be possible to add the reactants together in seconds,
improved results may accompany an addition rate of slow and steady
addition that is greater than about 1 hour. In one embodiment, the
addition is in a time range to completion of from about 1 hour to
about 3 hours. In one embodiment, the addition time occurs in an
amount of from about 1 hour to about 2 hours, or from about 2 hours
to about 3 hours. Adding the reactants in a continuous flow has a
different effect relative to adding aliquots in a stepwise fashion
over the addition period.
[0036] In one embodiment, the silver composition may be selected
from a group consisting of silver salt of inorganic acids, silver
salt of organic acids, and silver oxides. The silver may be present
in an amount of at least about three weight percent based on a
total weight of the substrate in one embodiment. In other
embodiment, the silver may be present in an amount of less than or
equal to about ten weight percent of a total weight of the
substrate.
[0037] In one embodiment, the catalyst metal is selected from
gallium, indium, iron, zirconium zinc, rhodium, platinum, or
tungsten. The catalyst metal may be in elemental form, a complex,
or as an oxide or equivalent form. For example, the catalyst metal
may include tungstate or zirconate. In one embodiment, rather than
an oxide form, the complex may include a nitride, carbide,
silicide, boride, or aluminide. In one embodiment, the catalyst
metal includes both gallium (Ga) and indium (In). In one
embodiment, the catalyst metal consists essentially of iron. In one
embodiment, the catalyst metal consists essentially of zirconium.
In one embodiment, the catalyst metal consists essentially of zinc.
In one embodiment, the catalyst metal consists essentially of
rhodium. In one embodiment, the catalyst metal consists essentially
of platinum. In one embodiment, the catalyst metal consists
essentially of tungsten. The choice of catalyst material, the
amount, and the combination (if any) or ratio of the combined
materials has a direct effect on the function and properties of the
resultant product.
[0038] In one method of making the catalyst, a metal alkoxide, a
silver composition, a catalyst metal and a templating agent are
mixed in a vessel with a suitable solvent to form a reaction
product. Initially, the reaction product may be in the form of a
sol. The sol may be converted to a gel by the sol gel process. The
gel may be subject to one or more of filtration, washing, drying
and calcinating to yield a solid catalyst composition that includes
the catalytic metal disposed on a porous substrate.
[0039] The effect of iron on Ag-Templated Alumina catalytic
activity is tested by varying the method by which silver is added
to templated alumina (TA). The alternative method for introducing
silver or any other element is called incipient wetness method
whereby the precursor is added to the hydrolyzed and condensed
templated alumina as an aqueous solution that wets the alumina
followed by calcination. Templated alumina with sol gel silver had
superior activity for NOx reduction than templated alumina with
incipient wetness (IW) silver. There are alternative methods of
adding silver or any other element in the templated alumina and
those methods are known as impregnation methods. In one embodiment,
the incipient wetness method is a type of impregnation method.
[0040] During the calcination process, the silver composition may
be reduced to a catalytic metal. The calcination may be conducted
at a temperatures in a range of from about 350 degrees Celsius to
about 400 degrees Celsius, from about 400 degrees Celsius to about
500 degrees Celsius, from about 500 degrees Celsius to about 600
degrees Celsius, from about 600 degrees Celsius to about 700
degrees Celsius, or from about 700 degrees Celsius to about 800
degrees Celsius. In one embodiment, the calcination may be
conducted at a temperature of about 550 degrees Celsius. The
calcination may be conducted for a period of from about 10 minutes
to about 30 minutes, from about 30 minutes to about 60 minutes,
from about 60 minutes to about 1 hour, from about 1 hour to about
10 hours, from about 10 hours to about 24 hours, or from about 24
hours to about 48 hours.
[0041] Suitable solvents may include aprotic polar solvents, polar
protic solvents, and non-polar solvents. Suitable aprotic polar
solvents may include propylene carbonate, ethylene carbonate,
butyrolactone, acetonitrile, benzonitrile, nitromethane,
nitrobenzene, sulfolane, dimethylformamide, N-methylpyrrolidone, or
the like. Suitable polar protic solvents may include water,
nitromethane, acetonitrile, and short chain alcohols. Suitable
short chain alcohols may include one or more of methanol, ethanol,
propanol, isopropanol, butanol, or the like. Suitable non-polar
solvents may include benzene, toluene, methylene chloride, carbon
tetrachloride, hexane, diethyl ether, or tetrahydrofuran.
Co-solvents may also be used. Ionic liquids may be used as solvents
during gelation. Exemplary solvents may include short-chain
alcohols, such as 2-butanol and 2-propanol.
[0042] Selection of the type(s) and amounts of the templating agent
may affect or control the pore characteristics of the resultant
templated substrate. Suitable templating agents may include one or
more surfactants. Suitable surfactants may include cationic
surfactants, anionic surfactants, non-ionic surfactants, or
Zwitterionic surfactants. In one embodiment, the templating agent
may include one or more cyclic species. Examples of such cyclic
species may include cyclodextrin and crown ether.
[0043] Suitable cationic surfactants may include cetyltrimethyl
ammonium bromide (CTAB), cetylpyridinium chloride (CPC),
polyethoxylated tallow amine (POEA), benzalkonium chloride (BAC),
and benzethonium chloride (BZT). Other suitable cationic
surfactants may include those having a chemical structure denoted
by CH.sub.3(CH.sub.2).sub.15N(CH3).sub.3-Br,
CH.sub.3(CH.sub.2).sub.15-(PEO)n-OH where n=2 to 20 and where PEO
is polyethylene oxide, CH.sub.3(CH.sub.2).sub.14COOH and
CH.sub.3(CH.sub.2).sub.15NH.sub.2. Other suitable cationic
surfactants may include one or more fluorocarbon surfactants, such
as
C.sub.3F.sub.7O(CFCF.sub.3CF.sub.2O).sub.2CFCF.sub.3--CONH(CH.sub.2).sub.-
3N(C.sub.2H.sub.5).sub.2CH.sub.3I), which is commercially available
as FC-4.
[0044] Suitable anionic surfactants may include one or more of
sodium dodecyl sulfate (SDS), ammonium lauryl sulfate, alkyl
sulfate salts, sodium laureth sulfate also known as sodium lauryl
ether sulfate (SLES), alkyl benzene sulfonate, soaps, fatty acid
salts, or sodium dioctyl sulfonate (AOT). Suitable Zwitterionic
surfactants may include dodecyl betaine, dodecyl dimethylamine
oxide, cocamidopropyl betaine, or coco ampho-glycinate.
[0045] Nonionic surfactants may have polyethylene oxide molecules
as hydrophilic groups. Suitable ionic surfactants may include alkyl
poly(ethylene oxide), copolymers of poly(ethylene oxide) and
poly(propylene oxide) commercially called Poloxamers or Poloxamines
and commercially available under the trade name PLURONICS from the
BASF company.
[0046] Suitable non-ionic surfactants may include one or more alkyl
polyglucosides, octylphenol ethoxylate, decyl maltoside, fatty
alcohols, cetyl alcohol, oleyl alcohol, cocamide monoethanolamine,
cocamide diethanolamine, cocamide triethanolamine,
4-(1,1,3,3-tetramethyl butyl)phenyl-poly (ethylene glycol),
polysorbitan monooleate, or amphiphilic poly (phenylene ethylene)
(PPE). Suitable poly glucosides may include octyl glucoside. Other
suitable non-ionic surfactants may include long-chain alkyl amines,
such as primary alkylamines and N,N-dimethyl alkylamines. Suitable
primary alkylamines may include dodecylamine and hexadecylamine.
Suitable N,N-dimethyl alkylamines may include N,N-dimethyl
dodecylamine or N,N-dimethyl hexadecylamine. Suitable non-ionic
surfactant may include
(1,1,3,3-Tetramethylbutyl)phenyl-polyethylene glycol, which is
commercially available as TRITON X-114 from the Sigma-Aldrich
company.
[0047] In one embodiment, the templating agent may include
cyclodextrin. Cyclodextrins may include cyclic oligosaccharides
that include five or more .alpha.-D-glucopyranoside units linked 1
to 4, as in amylose (a fragment of starch). Suitable cyclodextrins
in the templating agent may include 5-membered to about
150-membered cyclic oligosaccharides. Exemplary cyclodextrins
include a number of glucose monomers ranging from six to eight
units in a ring. Suitable cyclodextrins are .alpha.-cyclodextrin, a
six membered sugar ring molecule; .beta.-cyclodextrin, a seven
sugar ring molecule; .gamma.-cyclodextrin, an eight sugar ring
molecule; or the like.
[0048] As noted above, the templating agent may include crown
ethers. Crown ethers are heterocyclic chemical compounds that
include a ring containing several ether groups. Suitable crown
ethers may include oligomers of ethylene oxide, the repeating unit
being ethyleneoxy, i.e., --CH2CH2O--. Useful members of this series
may include the tetramer (n=4), the pentamer (n=5), and the hexamer
(n=6). Crown ethers derived from catechol may be used in the
templating agent. Crown ethers that strongly bind certain types of
cations to form complexes may be included in the templating agents.
The oxygen atoms in the crown ether may coordinate with a cation
located at the interior of the ring, whereas the exterior of the
ring may be hydrophobic. For example, 18-crown-6 has high affinity
for potassium cation, 15-crown-5 for sodium cation, and 12-crown-4
for lithium cation.
[0049] In one embodiment, a method of using the said catalyst
composition may be by introducing a gas stream in a chamber having
a composition comprising a templated metal oxide substrate having a
plurality of pores, a catalyst material comprising silver. The
silver may be present in an amount of at least about three weight
percent based on a total weight of the substrate. The nitrogen
oxide present in the gas stream may be reduced at a temperature of
about 275 degrees Celsius or greater. In one embodiment, the
reduction may occur at a temperature range of from about 275
degrees Celsius to about 300 degrees Celsius, from about 300
degrees Celsius to about 325 degrees Celsius, or from about 325
degrees Celsius to about 350 degrees Celsius. The nitrogen oxide
present in the gas stream may be reduced at a temperature of less
than about 350 degrees Celsius in the chamber.
[0050] As noted in the disclosure, the composition can include a
templated mesoporous metal oxide substrate, catalyst metal, and an
amount silver. The composition can be entirely free of alkaline
earth metal, and may reduce NOx without absorbing the NOx on the
catalyst material surface. Further, possibly owing to the method of
formation, the templated metal oxide and silver may have a
distinguishable visible-ultra-violet (VIS-UV) absorbance intensity
that is at least 20 percent less than a standard silver alumina
catalyst (Ag STD) at a wavelength in a range of from about 350 nm
to about 500 nm, at under H.sub.2 at 30 degrees Celsius. The
standard silver alumina has alumina as Norton alumina, and which
have the same amount of silver by weight. One difference affecting
the absorbance may be the form, size and distribution of the silver
relative to the templated metal oxide. The addition of the catalyst
metal may further affect the efficacy, performance and function of
the final reaction product.
EXAMPLES
Example 1
[0051] A process for templated alumina includes the preparation of
the following solutions. Solution 1 is ethyl acetoacetate (26.5 g,
0.2 mol), TRITON X-114 (85 g, ca. 0.15 mol) and 2-butanol (500 mL),
which are combined in a 5-liter, 3-neck flask equipped with an
addition funnel, a condenser a mechanical stirrer. Solution 2 is
Al(O-secBu).sub.3 (500 g, 2 mol) and 2-BuOH (2 L). Solution 3 is
water (75 mL, 4 mol) and 2-BuOH (850 mL).
[0052] Solution 1 is added to Solution 2 with stirring, and the
combined volume is held at ambient temperature for 30 minutes.
Solution 3 is added to the combined solutions 1 and 2 via an
addition funnel over 90 minutes. Mechanical stirring continues at
ambient temperature for 3 hours, and the contents are heated to
reflux for about 20 to 24 hours.
[0053] The contents are cooled and are filtered on #50 filter
paper. The contents are washed with ethanol. The obtained white
solid is dried in a vacuum oven at 80 degrees Celsius. The solid is
subjected to Soxhlet extraction with ethanol for 20-24 h. The solid
is dried in a vacuum oven at 80 degrees Celsius, and yields 164
grams. The dry material is heated under N.sub.2 in a tube furnace
from room temperature to 550 degrees Celsius at a heating rate of 2
degrees Celsius/minute, maintained at 550 degrees Celsius for 1 hr
and finally calcined in a flow of air at 550 degrees Celsius for 5
hours.
[0054] A process for forming templated metal oxide with silver
includes the following. A 5-liter, 3-necked flask equipped with a
mechanical stirrer, a reflux condenser, and an addition funnel is
charged with TRITON X114 (68.7 g, 0.16 mol) and ethylacetoacetate
(13.2 g, 0.1 mol) in 250 mL of 2-propanol. An amount of
Al(O.sup.secBu).sub.3 (249.8 g, 1.02 mol) that is dissolved or
suspended in 1-liter of 2-propanol is added to the flask. The
contents are stirred for 30 minutes. An amount of silver nitrate
(AgNO.sub.3) is dissolved in water (37 mL, 2.06 mol). The silver
nitrate solution is changed/varied as noted below to create a
number of reaction products. The silver nitrate solution is
combined with 500 mL of 2-propanol and is charged to an addition
funnel. The contents of the addition funnel are added to a 5-liter
flask over the course of 75 minutes. The stirred solution is
refluxed for 24 hours.
[0055] After cooling, the contents are filtered and washed with
about 250 mL of ethanol to obtain a semi-dried mass. The semi-dried
mass is subjected to Soxhlet extraction with ethanol for 24 hours
and oven-vacuum dried at 30 mmHg for 24 hours to obtain a solid.
The obtained brown solid is condensed, which here is calcined,
under nitrogen in a tube furnace to 550 degrees Celsius at a
heating rate of 2 degrees Celsius/minute to obtain a reaction
product.
[0056] A series of Catalyst Products are formed. The amount of
AgNO.sub.3 (2.6 g, 0.0158 mol) for Catalyst Product 1, results in 3
percent silver templated alumina catalyst composition. The amount
of AgNO.sub.3 (3.463 g, 0.0204 mol) for Catalyst Product 2, results
in 4 percent silver templated alumina catalyst composition. The
amount of AgNO.sub.3 (4.407 g, 0.0259 mol) for Catalyst Product 3,
results in 5 percent silver templated alumina catalyst composition.
The amount of AgNO.sub.3 (5.383 g, 0.0317 mol) for Catalyst Product
4, results in 6 percent silver templated alumina catalyst
composition. The amount of AgNO.sub.3 (6.391 g, 0.0376 mol) for
Catalyst Product 5, results in 7 percent silver templated alumina
catalyst composition. The amount of AgNO.sub.3 (7.49 g, 0.0441 mol)
for Catalyst Product 6, results in 8 percent silver templated
alumina catalyst composition. The amount of AgNO.sub.3 (8.443 g,
0.0497 mol) for Catalyst Product 7, results in 9 percent silver
templated alumina catalyst composition.
[0057] Catalyst Product 8--Templated Alumina with 8 percent Silver
having a different solvent: A 5 L 3-neck round bottom flask
equipped with a mechanical stirrer, reflux condenser, and addition
funnel is charged with ethyl acetoacetate (13.26 g, 0.1019 mol),
TRITON X114 (69.73 g, 0.1117 mol) and 250 mL of 2-Butanol. The
stirrer is turned on low. Aluminum sec-butoxide (250.96 g, 1.0188
mol) is dissolved in 1 Liter of 2-BuOH and transferred to the 5 L
flask. This reaction mixture is stirred under ambient conditions
for 30 minutes. AgNO.sub.3 (7.49 g, 0.0441 mol) is dissolved in
37.5 mL of distilled H.sub.2O and combined with 425 mL of 2-BuOH to
produce a transparent, clear solution. This solution is added via
dropping funnel to the 5 L flask. The stir speed is adjusted to
account for changing viscosity of the fluid, water addition
occurred over the course of 2-3 hours. The mixture is aged at 95
degrees Celsius for 24 hours.
[0058] Two different processes are carried out with portions of the
obtained slurry. 1.) Alumina-water slurry. Distilled water (1.47 L)
is added to the flask in order to remove butanol via azeotropic
distillation (bp ca. 87 degrees Celsius) and to yield a water
slurry of 5 percent solids. 2.) Extracted Solid. The obtained
slurry described above is filtered through a #50 filter paper on a
Buchner funnel, washed with ethanol and the obtained solid is
extracted with ethanol in a Soxhlet apparatus. The solid is dried
in a vacuum oven at 80 degrees Celsius, yielding 164 grams. The dry
material is heated under N.sub.2 in a tube furnace from room
temperature to 550 degrees Celsius at a heating rate of 2 degrees
Celsius/min, maintained at 550 degrees Celsius for 1 hr and
calcined in a flow of air at 550 degrees Celsius for 5 hours to get
Catalyst Product 8.
[0059] FIG. 5 is a graph that plots VIS-UV absorbance intensity at
different wavelengths. The plot compares the Comparative Ag STD, Ag
TA (sol-gel) and Ag TA (impregnated), all having the same Ag
percent. The test conditions are under H.sub.2 at 30 degrees
Celsius (spectra have been subtracted with the ones from fresh
catalyst under He at 30 degrees Celsius). The Ag TA (sol-gel) is a
silver templated alumina catalyst made by the sol gel process and
Ag TA (impregnated) is a silver templated alumina catalyst made by
the impregnation process. Particularly, Curve 16 is a comparative
plot for 8 percent Ag with standard Norton alumina under H.sub.2 at
30 degrees Celsius. Curve 18 is a plot for 8 percent Ag with
templated alumina made by sol gel method under H.sub.2 at 30
degrees Celsius (Catalyst Product 8). Curve 20 is a plot for 8
percent Ag with templated alumina made by impregnation method under
H.sub.2 at 30 degrees Celsius. In FIG. 5, curve 16 indicates the
amount of silver ion (Ag.sup.+) agglomeration, the peak is
identified with reference number 22, silver (Ag) cluster
agglomeration, peak 24, and Ag particles agglomeration, peak
26.
[0060] FIG. 6 is a graph that plots VIS-UV absorbance intensity at
different wavelengths. Curve 28 is a comparative plot for 8 percent
Ag with standard Norton alumina under H.sub.2 at 300 degrees
Celsius. Curve 30 is a plot for 8 percent Ag with templated alumina
made by sol gel method under H.sub.2 at 300 degrees Celsius
(Catalyst Product 6). Curve 32 is a plot for 8 percent Ag with
templated alumina made by impregnation method under H.sub.2 at 300
degrees Celsius. For the standard silver alumina catalyst (curve
18) the agglomeration is very high whereas for the silver templated
alumina catalyst the agglomeration is low, showing the relatively
different properties with regard to the silver templated alumina
catalyst.
[0061] With respect to FIG. 6 the graph that shows the Catalyst
Product 6 is having a VIS-UV absorbance intensity that is at least
20 percent less than a comparative silver alumina catalyst (Ag
STD). The standard alumina is Norton alumina, and which has the
same amount of silver by weight, at a wavelength in a range of from
about 350 nm to about 500 nm, under H.sub.2 at 30 degrees
Celsius.
[0062] Catalyst Product 6 has a visible-ultra-violet (VIS-UV)
absorbance intensity that is at least 20 percent less than a
standard silver alumina catalyst (Ag STD), under H.sub.2 at 30
degrees Celsius and at a wavelength that is in a range of from
about 350 nanometers (nm) to about 500 nm. The standard alumina is
Norton alumina, and has the same amount of silver by weight as the
instant composition. FIGS. 5 and 6 indicate an amount of silver
(Ag) agglomeration (Ag particles and mainly Ag clusters) and silver
ion (Ag.sup.+) agglomeration. For the standard silver alumina
catalyst, the agglomeration is relatively high, whereas for the
silver templated alumina catalyst the agglomeration is relatively
low. The agglomeration level affects, and possibly controls, the
function and efficacy of the corresponding material.
Example 2
Zirconium
[0063] In the following examples, at least one compositional
species is shown in detail. Compositional variations are performed
for the purpose of examining larger data sets, but are not included
in detail for the sake of clarity. Example 2 includes the
preparation of 3 percent Ag-templated alumina (TA)+0.25 percent Zr
as Zr(O(CH.sub.2).sub.3CH.sub.3).sub.4--CH.sub.3(CH.sub.2).sub.3OH
replacing Alumina. A 1000 mL 3-neck round bottom flask is set-up in
an oil bath with stir bar and equipped with a mechanical stirrer,
reflux condenser and addition funnel. A dropping funnel for
hydrolysis later replaces the addition funnel.
[0064] An amount of 50.81 g (0.2063 mol) of Aluminum sec-butoxide
(Al(O.sup.secBu).sub.3) are dissolved in 200 mL of 2-Butanol
(2-BuOH) and added to the flask. The 2-BuOH is divided in half, one
used to transfer the Al(O.sup.secBu).sub.3 and the other the rinse
the remaining portion from the container walls. After addition to
the flask, the mechanical stirrer is turned on using a low setting.
2.674 g (0.0205 mol) of Ethyl acetoacetate (EA), 14.084 g (0.02257
mol) Triton X-114, and 60 mL 2-BuOH are combined and added to the
flask with the Al(O.sup.secBu).sub.3 solution. This solution is
allowed to stir under ambient conditions for 30 minutes. 0.243 g
(5.308E-04 moles)
Zr(O(CH.sub.2).sub.3CH.sub.3).sub.4--CH.sub.3(CH.sub.2).sub.3OH are
dissolved in 2-BuOH for transfer and added to the flask. The
mixture is stirred for additional time at a medium pace. AgNO.sub.3
(0.5356 g, 0.00315 mol) is dissolved in 7.5 mL H.sub.2O and is
combined with 85 mL of 2-BuOH. This solution is added to the
dropping funnel, which is put in place of the addition funnel.
After approximately 45 minutes elapsed, the dropping funnel is
turned on and allowed to drip at a controlled pace. Controlling the
addition rate and operating parameters affects the hydrolysis rate,
and therefore the properties and function of the reaction
product.
[0065] After the hydrolysis is complete, the stirrer is turned up
to account for the gaining viscosity of the mixture and a stopper
replaced the dropping funnel. The mixture is stirred under ambient
conditions for approximately 3 hours following the completion of
hydrolysis. After 3 hours, the reaction mixture is aged at 95
degrees Celsius for 24 hours with stirring. The resulting gel is
filtered overnight and extracted using Soxhlet Extraction with
ethanol (EtOH) for 24 hours. The extracted solid is dried in a
vacuum oven at 50 degrees Celsius overnight.
[0066] Several samples are prepared, each having 3 percent Ag TA
and each having a differing level of zirconia. Some of these new
materials show enhanced catalytic activity, and are shown compared
to 3 percent Ag TA alone. FIGS. 7 and 8 are graphical
representations of average NOx Conversion, and standard deviation,
at 325 degrees Celsius (FIG. 7) and 375 degrees Celsius (FIG. 8)
for 3 percent Ag-TA (far left); 3 percent Ag-TA with 1 percent
zirconia (middle); and 3 percent Ag-TA 10 percent zirconia (far
right). As shown with reference to FIGS. 7 and 8, the improved
activity occurred with a 1 percent but not with 10 percent
framework substitution of aluminum with zirconium. Unexpectedly,
adding more catalyst metal had the reverse effect on efficacy.
[0067] FIGS. 9 and 10 are graphical representations of average NOx
Conversion and standard deviation at 325 degrees Celsius (FIG. 9)
and 375 degrees Celsius (FIG. 10) for differing values of catalyst
metal. As shown in FIGS. 9 and 10, catalytic activity for NOx
reduction varies as a function of zirconia loading and of
temperature. A 0.5 to 1 mol percent zirconia has the highest
activity compared to the other zirconia-containing compositions in
the experiment. Simply adding more catalyst metal does not increase
efficacy.
Example 3
Iron
[0068] Example 3 includes the preparation of 3 percent Ag-Templated
alumina (TA) with 0.5 percent iron (Fe) as
Fe(NO.sub.3).sub.2.9H.sub.2O supported by Al.sub.2O.sub.3. A
1-liter, 3-neck round bottom flask is set-up in an oil bath with
stir bar and equipped with a mechanical stirrer, reflux condenser
and addition funnel. A dropping funnel for hydrolysis later
replaced the addition funnel. After the set-up is complete, 50.9 g
(0.2066 mol) of Aluminum sec-butoxide (Al(O.sup.secBu).sub.3) are
dissolved in 200 mL of 2-Butanol (2-BuOH) and added to the flask.
The 2-BuOH is divided in half, one used to transfer the
Al(O.sup.secBu).sub.3 and the other to remove the remaining portion
from the container walls. Following the addition to the flask, the
mechanical stirrer is turned on using a low setting. 2.648 g
(0.0203 mol) of Ethyl acetoacetate (EA), 14.150 g (0.02268 mol)
Triton X-114, and 60 mL 2-BuOH are combined and added to the flask
with the Al(O.sup.secBu).sub.3 solution. The mixture is stirred for
30 minutes at a medium pace. During the 30-minute ambient stir
period, 0.5345 g (0.003147 mol) of AgNO.sub.3 are dissolved in 7.6
mL H.sub.2O and combined with 85 mL of 2-BuOH. This solution is
added to the dropping funnel, which is put in place of the addition
funnel. After the 30 minutes elapsed, the dropping funnel is turned
on and allowed to drip at a medium pace. After the hydrolysis is
complete, the stirrer is turned up to gain viscosity of the mixture
and a stopper replaces the dropping funnel.
[0069] The mixture is stirred under ambient conditions for
approximately 3 hours following the completion of hydrolysis. After
3 hours, the reaction mixture is aged at 95 degrees Celsius for 24
hours with stirring. Approximately 30 minutes before the completion
of the aging period, 0.2062 g (5.104E-04 mol) of
Fe(NO.sub.3).sub.2-9H.sub.2O is dissolved in just enough deionized
H.sub.2O and added to the flask. The mixture is allowed to stir for
an extra hour. The resulting gel is filtered overnight and
extracted using Soxhlet Extraction with ethanol (EtOH) for 24
hours. The extracted solid is dried in a vacuum oven at 50 degrees
Celsius overnight.
[0070] FIGS. 11 and 12 are graphical representations of average NOx
conversion, and standard deviation, at 325 degrees Celsius (FIG.
11) and 375 degrees Celsius (FIG. 12) for (from left to right) 3
percent Ag-TA sol gel; 3 percent Ag-TA IW; 3 percent Ag-TA with 1
percent iron IW; 3 percent Ag-TA with 0.5 percent iron IW; and 3
percent Ag-TA with 0.1 percent iron IW. As shown in FIGS. 11 and
12, TA with sol gel silver had superior activity for NOx reduction
than TA with incipient wetness (IW) silver. However, it is
unexpected that the level of activity that is achievable with the
sol-gel method can be achieved using incipient wetness method, by
the addition of a transition metal as a catalyst--in this instance
iron. Some TA with IW silver and IW iron of various levels
displayed catalytic activity similar to that for Ag-TA sol gel.
Also, unexpectedly, there is an inflexion point such that there is
not a proportional relationship between the amount of catalyst
material and the efficacy. That is, merely adding more catalyst
does not increase catalytic activity. At the higher test
temperature, the indicated trend is that adding less iron increases
the catalytic activity until some point where no iron is present,
and at which point the efficacy plummets.
Example 4
Gallium and Indium
[0071] Example 4 includes the preparation of 3 percent Ag-Templated
Alumina with a combination of 2 percent gallium and 0.5 percent
indium. A 1-liter, 3-necked flask equipped with a mechanical
stirrer and an addition funnel is charged with
Al(O.sup.secBu).sub.3 (97.5 g, 0.396 mol) and dissolved in 400 ml
2-butanol. Ga(OiPr).sub.3 (2.0054 g, 0.00812 moles) is added to the
stirring reaction mixture as a solid. In(OiPr).sub.3 (11.86 ml
solution 5 percent w/v, 0.00203 moles) is also added to the
reaction mixture via a syringe. The flask is charged with ethyl
acetoacetate (5.3 grams, 0.04 mol) and TRITON X-114 (28 grams) in
120 ml 2-butanol. The reaction mixture is stirred until all the
Ga(OiPr).sub.3 is dissolved (about 2 hrs) at room temperature. A
solution composed of 170 ml 2-butanol, 15 ml H.sub.2O, AgNO.sub.3
(1.0398 g, 0.0061moles) is added drop wise from a dropping funnel
to the reaction mixture under continuous stirring from an overhead
stirrer. After addition of the entire amount of the water solution,
the resulting reaction mixture is stirred at room temperature for 3
hours, and is aged for 24 hours at 95 degrees Celsius. The
resulting gel is filtered overnight. The excess surfactant is
removed by Soxhlet extraction with ethanol for 24 hours. The
obtained solid is dried in a vacuum oven at 50 degrees Celsius
overnight.
[0072] FIGS. 13 and 14 are graphical representations of average NOx
conversion, and standard deviation, at 325 degrees Celsius (FIG.
13) and 375 degrees Celsius (FIG. 14) for 3 percent Ag-TA with
(from left to right): 2 percent gallium and 1 percent indium; 5
percent gallium and 0.5 percent indium; 2 percent gallium and 0.5
percent indium; 5 percent gallium and 1 percent indium; and (far
right) a 3 percent Ag-TA only control. FIGS. 13 and 14 show
relatively improved NOx conversion at 375 degrees Celsius for the 3
percent Ag-TA materials with 2 percent gallium and 1 percent
indium, 5 percent gallium 0.5 percent indium and 2percent gallium
0.5 percent indium. There is no improvement observed for the 3
percent Ag-TA with 5 percent gallium and 1 percent indium. Lower
levels of gallium and indium, alone or in combination, or differing
ratio's could have relatively better catalytic activity for NOx
reduction. There appears to be a range of improved activity at a
ratio of Ga:In of greater than 2:1.
Example 5
Tungsten
[0073] Example 5 includes the preparation of 3 percent Ag-Templated
Alumina 1.5 percent silver tungstate. A 1-liter, 3-necked flask
equipped with a mechanical stirrer and an addition funnel is
charged with Al(O.sup.secBU).sub.3 (100 g, 0.40568 mol) and
dissolved in 400 ml 2-butanol. The flask is next charged with ethyl
acetoacetate (5.3 g, 0.04 mol) and TRITON X-114 (28 g) in 120 ml
2-Butanol. The reaction mixture is stirred for 30 minutes at room
temperature. A solution composed of 170 ml 2-butanol and 15 ml
H.sub.2O is added drop-wise from a dropping funnel to the reaction
mixture under continuous stirring by an overhead stirrer. After
addition of the entire amount of water and 2-butanol solution, the
resulting reaction mixture is allowed to stir at room temperature
for 3 hours, and is aged for approximately 12 hours at 95 degrees
Celsius.
[0074] A solution prepared by dissolving Ag.sub.2WO.sub.4 (1.4331
g) in the minimum amount of water and NH.sub.40H is added
drop-wise, under strong stirring to the reaction mixture. The
resulting mixture is allowed to age for another 12 hours at 95
degrees Celsius, it is filtered overnight. The excess surfactant is
removed by Soxhlet extraction with ethanol for 24 hours. The
obtained solid is dried in a vacuum oven at 50 degrees Celsius
overnight.
[0075] FIGS. 15 and 16 are graphical representations of average NOx
Conversion and standard deviation at 325 degrees Celsius (FIG. 15)
and 375 degrees Celsius (FIG. 16) for (left to right): 3 percent
Ag-TA sol gel; 3 percent Ag-TA IW; 3 percent Ag.sub.2WO.sub.4-TA
sol gel; 3 percent Ag.sub.2WO.sub.4 TA IW; 2 percent Ag and 0.5
percent Ag.sub.2WO.sub.4 sol gel (note enhanced activity); 2
percent Ag and 0.5 percent Ag.sub.2WO.sub.4 IW; 1.5 percent
Ag.sub.2WO.sub.4 sol gel; and 1.5 percent Ag.sub.2WO.sub.4IW. In
FIGS. 15 and 16, at 375 degrees Celsius an enhancement of activity
with 0.5 percent Ag.sub.2WO.sub.4 and 2 percent silver is noted. An
equivalent, or better effect, is possible with a lesser total
amount of silver.
Example 6
Zinc
[0076] Example 6 includes the preparation of 3 percent Ag-Templated
Alumina with 0.5 percent zinc. A 1-liter, 3-neck round bottom flask
equipped with a mechanical stirrer, reflux condenser and addition
funnel is charged with Al(O.sup.secBU).sub.3 (49.95 g, 0.2028 mol).
200 mL of 2-Butanol (2-BuOH) are added to the flask. The 2-BuOH is
divided in half, one used to transfer the Al(O.sup.secBU).sub.3 and
the other the rinse the remaining portion from the container
walls.
[0077] Following the addition to the flask, the mechanical stirrer
is turned on using a low setting and the flask is charged with
ethyl acetoacetate (2.655 g, 0.0204 mol), TRITON X-114 (14.05 g,
0.0225 mol) and 60 mL 2-BuOH. This solution is stirred under
ambient conditions for 30 minutes. During this time, of AgNO.sub.3
(0.5352 g, 0.00315 mol) and Zn(NO.sub.3).sub.2.6H.sub.2O (0.1539 g,
5.1735E-.sup.04 mol) are dissolved in 7.5 mL H.sub.2O and combined
with 85 mL of 2-BuOH. This solution is added to the addition
funnel. After 30 minutes have elapsed, the addition funnel is
turned on and allowed to drip at a controlled pace. The drip rate
controls the rate of hydrolysis, which in turn can affect the
property and function of the reaction product.
[0078] After the hydrolysis is complete, the stirrer is turned up
to account for the gaining viscosity of the mixture and a stopper
replaced the dropping funnel. The mixture is allowed to stir under
ambient conditions for approximately 3 hours following the
completion of hydrolysis. After the 3 hours of stirring, the
reaction mixture is aged at 95 degrees Celsius for 24 hours with
stirring to form a gel. The resulting gel is filtered and extracted
using Soxhlet extraction with ethanol for 24 hours to form a solid.
The extracted solid is dried in a vacuum oven at 50 degrees Celsius
overnight.
[0079] FIGS. 17 and 18 are graphical representations of average NOx
Conversion and standard deviation at 325 degrees Celsius and 375
degrees Celsius for (left to right) 3 percent Ag-TA; 3 percent
Ag-TA with 1 percent zinc sol gel; 3 percent Ag-TA with 1 percent
zinc IW; 3 percent Ag-TA with 0.5 percent zinc IW; and 3 percent
Ag-TA with 0.1 percent zinc IW. FIGS. 17 and 18 show that several
levels of zinc at temperatures 325 degrees Celsius and 375 degrees
Celsius gave improved catalytic activity for NOx conversion
compared with 3 percent Ag-TA alone.
Example 7
Platinum
[0080] Example 7 includes the preparation of 3 percent Ag-Templated
Alumina with 0.05 percent platinum. A 1-liter, 3-neck round bottom
flask equipped with a mechanical stirrer, reflux condenser and
addition funnel is charged with Al(O.sup.secBU).sub.3) (50.025 g,
0.203 mol). An aliquot of 200 mL of 2-Butanol (2-BuOH) is added to
the flask. The 2-BuOH is divided in half, one used to transfer the
Al(O.sup.secBU).sub.3 and the other the rinse the remaining portion
from the container walls. Following the addition to the flask, the
mechanical stirrer is turned on using a low setting and the flask
is charged with ethyl acetoacetate (2.655 g, 0.0204 mol), TRITON
X-114 (14.099 g, 0.0226 mol) and 60 mL 2-BuOH. Platinum (II)
acetylacetonate (0.0210 g, 5.34E-05 mol) is added to the flask. The
solution is allowed to stir under ambient conditions for 30
minutes. During this time, of AgNO.sub.3 (0.5352 g, 0.00315 mol) is
dissolved in 7.5 mL H.sub.2O and combined with 85 mL of 2-BuOH.
This solution is added to the addition funnel. After 30 minutes had
elapsed, the addition funnel is turned on and allowed to drip at a
medium pace.
[0081] After the hydrolysis is complete, the stirrer is turned on
to gain viscosity of the mixture and a stopper replaced the
dropping funnel. The mixture is stirred under ambient conditions
for approximately 3 hours following the completion of hydrolysis.
After 3 hours, the reaction mixture is aged at 95 degrees Celsius
for 24 hours with stirring. The resulting gel is filtered and
extracted using Soxhlet extraction with ethanol for 24 hours. The
extracted solid is dried in a vacuum oven at 50 degrees Celsius
overnight.
[0082] FIG. 19 is a graphical representation of average NOx
conversion and standard deviation for (left to right) each at 275
degrees Celsius, 325 degrees Celsius and 375 degrees Celsius: 3
percent Ag-TA; 3 percent Ag-TA with 0.01 percent Platinum; 3
percent Ag-TA; and 3 percent Ag-TA with 0.05 percent iridium.
Example 8
Rhodium
[0083] Example 8 includes the preparation of 3 percent Ag-Templated
Alumina 0.05 percent rhodium. A 1-liter, 3-neck round bottom flask
equipped with a mechanical stirrer, reflux condenser and addition
funnel is charged with Al(O.sup.secBU).sub.3) (50.025 g, 0.203
mol). 200 mL of 2-Butanol (2-BuOH) is added to the flask. The
2-BuOH is divided in half, one used to transfer the
Al(O.sup.secBU).sub.3 and the other the rinse the remaining portion
from the container walls. Following the addition to the flask, the
mechanical stirrer is turned on using a low setting and the flask
is charged with ethyl acetoacetate (2.655 g, 0.0204 mol), TRITON
X-114 (14.099 g, 0.0226 mol) and 60 mL 2-BuOH. Rhodium (III)
acetylacetonate (0.0201 g, 5.02E-05 mol) is added to the flask.
This solution is allowed to stir under ambient conditions for 30
minutes. During this time, of AgNO.sub.3 (0.5352 g, 0.00315 mol) is
dissolved in 7.5 mL H.sub.2O and combined with 85 mL of 2-BuOH. The
solution is added to the addition funnel. After 30 minutes had
elapsed, the addition funnel is turned on and allowed to drip at a
medium pace. After the hydrolysis is complete, the stirrer is
turned on to gain viscosity of the mixture and a stopper replaced
the dropping funnel. The mixture is stirred under ambient
conditions for approximately 3 hours following the completion of
hydrolysis. After 3 hours, the reaction mixture is aged at 95
degrees Celsius for 24 hours with stirring. The resulting gel is
filtered and extracted using Soxhlet extraction with ethanol for 24
hours. The extracted solid is dried in a vacuum oven at 50 degree
Celsius overnight.
[0084] FIG. 20 is a graphical representation of average NOx
conversion and standard deviation at four temperatures (left to
right) 275 degrees Celsius, 325 degrees Celsius, 375 degrees
Celsius and 425 degrees Celsius. For each temperature (left to
right) 3 percent Ag-TA; 3 percent Ag-TA with 0.01 percent rhodium;
and 3 percent Ag-TA with 0.05 percent rhodium. FIG. 20 shows that
depending on the temperature the 0.01 percent rhodium and the 0.05
percent rhodium (each added to 3 percent Ag-TA) had superior
catalytic activity compared to 3 percent Ag-TA alone.
[0085] FIG. 21 is a graphical representation of average NOx
conversion and standard deviation at four temperatures (left to
right) 275 degrees Celsius, 325 degrees Celsius, 375 degrees
Celsius and 425 degrees Celsius. For each temperature (left to
right) 3 percent with Ag-TA with 0.005 percent rhodium; 3 percent
Ag-TA with 0.01 percent rhodium; and 3 percent Ag-TA alone. As
shown in FIG. 21, at the four temperatures tested, rhodium appeared
to give catalytic activity enhancement compared to the 3 percent
Ag-TA alone.
[0086] Additional Examples and samples are created and formed by
affected the following parameters: the type of solvent, the amount
of solvent, the hydrolysis rate, the reaction temperature, the
amount of catalytic metal in addition to the silver, the amount of
silver, the combination of the various catalytic metals (with or
without silver), and the templated alumina support. These samples
are tested for efficacy in the same manner as the above-disclosed
samples.
Testing Procedures:
[0087] The reactor mixes gases (using mass flow controllers--MFCs,
Brooks and MKS) and up to two liquids (usually water and a liquid
reductant) are vaporized. The water and liquid reductant are pumped
in under pressure. The gas mixture enters the heated (.about.115
degrees Celsius) top box and goes into a manifold that contains 32
capillary exit tubes. The gas is restricted in the manifold and the
pressure builds up to -60 psi. Backpressure indicates the same
amount of gas is flowing out of each capillary. The capillaries
(stainless steel) open up into tubes (INCONEL, stainless steel)
where the catalyst is positioned. This zone is a copper block that
can be temperature controlled.
[0088] The catalyst powders (25-50 mg) are held in place by quartz
wool that has been wedged into the tube. Each tube can be
individually sampled by controlling the two switching valves. The
flow of the outlet stream is measured and recorded. The flow can be
diverted through a deep oxidation catalysts (Pt/Al.sub.2O.sub.3
from Johnson Matthey) to determine N.sub.2 selectivity. The flow
passes through a diluter (CAI, Model 701) that takes 25 m/min from
the reactor (which generally puts out .about.35-40 mL/min) and
mixes it with 1000 ml/min of N.sub.2 (.about.25:1 dilution). The
diluted sample is pulled though the CO/CO.sub.2 detector (CAI) by a
pump in the NO.sub.x detector (CAI, Model 600 HCLD). In generally
only the NO.sub.x value is recorded. It is possible to record the
NO and NO.sub.2 values separately. A LABVIEW program controls many
features of the reactor system. The software does not control the
MFCs but their settings are recorded. The software controls the
temperature of the reactor block and the switching of the values.
The software records, CO, CO.sub.2 and NO.sub.x from the analyzers.
After the feed is completely combusted over the Deep Oxidation
Catalyst (DOC) the reductant delivery is checked by measuring
CO.sub.2 level.
[0089] The screening conditions are as follows: gas composition: 12
percent O.sub.2, 600 ppm NO, 7 percent H.sub.2O, 1 ppm SO.sub.2 and
the balance N.sub.2. The catalysts are pretreated with 7 percent
H.sub.2O and 50 ppm SO.sub.2, 12 percent O.sub.2 for 7 hours at 450
degrees Celsius to "age" or sulfur soak the catalysts. The
reductant used is a liquid mixture composed of:
2,2,4,Trimethylpentane (64 weight percent), octane (7 weight
percent) and toluene (29 weight percent), also known as Moctane.
Another liquid reductant used in a few experiments is a
distillation cut (<210 degrees Celsius) of ultra low sulfur
diesel (ULSD) fuel. For all the experiments mentioned using the HTS
reactor, the C1:NO ratio used is 8 (C1:NO is defined as the number
of carbon atoms in the reductant stream per number of NO
molecules). Each run examines the catalysts at 3 different
temperatures 275 degrees Celsius, 375 degrees Celsius and 425
degrees Celsius and the catalysts are usually tested in
triplicates. Data is presented as percent NOx conversion by
measuring the NO.sub.x concentration through tube #1 with no
catalyst present and measuring the NO.sub.x concentration over the
other tubes with catalysts and determining the percent change.
[0090] The catalysts screened in the 32-tube reactor are prepared
by incipient wetness impregnation of the sized support (425-710
nanometers) with a AgNO.sub.3 solution. The volume of the
AgNO.sub.3 solution used is twice the pore volume of the support
and contained the correct number of moles of Ag to hit the target
mole percent. The pore volume of the support is obtained from the
BET measurement report. The catalysts containing 2 mole percent Ag
on Norton alumina is called AgSTD and is present in every run as a
control. The impregnated materials are dried in a vacuum oven at 80
degrees Celsius and calcinated in air at 600 degrees Celsius for 6
hours in a box furnace. The prepared catalysts are weighed out
(.about.50 mg) and placed in 2 ml GC vials until used in the
reactor. The exact weight of each catalyst is measured using a
Bohdan weighing robot.
Scale-up Reactor
[0091] The experimental setup is as follows. The catalyst to be
tested is installed in a quartz-tube reactor (19 mm I.D.) located
inside a furnace. Temperature, pressure, space velocity over the
catalyst, and gas composition at the inlet of the reactor are
controlled. This reactor is fully automated and experimental test
matrix can be run over an extended period of time (days or weeks).
Analytical lines allow for the measurement of NO, NO.sub.2
(chemiluminescence detector), CO, CO.sub.2 (IR detector), and
SO.sub.2 (UV-Vis detector). Also, a deep oxidation catalytic bed
located before the analytical lines can be either flown through or
by-passed. When by-passed, the NOx concentration measured
(NO+NO.sub.2) is referred to as "NOx concentration". When flown
through the Deep Oxidation Catalyst (DOC, Johnson-Matthey catalyst,
Pt/Al.sub.2O.sub.3, SV<20000 hr.sup.-1, T=450 degrees Celsius),
the NOx concentration measured (NO+NO.sub.2) is referred to as "NOt
concentration". Therefore, the difference between those two values
(NOx concentration-NOt concentration) corresponds to the quantity
of NOx species that reacted in the quartz-tube reactor to form new
chemicals, which are oxidized back to NO or NO.sub.2 in the DOC.
These nitrogen-containing species are called RONOs. RONOs are
unidentified by-products of the SCR reaction of NOx to
nitrogen.
[0092] Catalysts are tested under experimental conditions reported
in Table 1. The total powder catalyst weight is 2.7 grams. The
total volumetric flow rate over the catalyst is 3 SLPM.
[0093] The powder bed is placed at least 24'' from the inlet of the
quartz tube to allow for preheating of the feed gas. The powder bed
is packed between two 0.5 grams plugs of quartz wool.
TABLE-US-00001 TABLE 1 Experimental Conditions X's values (NO)
(ppm) 475, 610, 690 (O2) percent 12 C1:NO 6 H2:NO ratio 0, 3:1
(H2O) percent 7 Temperature 275, 375, 430 (degrees Celsius) (SO2)
(ppm) 0 CO (ppm) 250 CO2 (percent) 0
[0094] Moctane, Ethylene+Propylene (C2_C3), Ultra Low Sulfur Diesel
(ULSD) and Diesel Fraction 1 are used as reductants. Liquid
reductants are pumped by a HPLC pump (ASI model 500 G) and
vaporized/diluted at 300 degrees Celsius with nitrogen before being
injected in the reactor. Gaseous reductants are metered and
delivered with Mass Flow Controllers (MFCs). The amount of
reductant injected is quantified by deep oxidation on
Pt/Al.sub.2O.sub.3 catalyst at 450 degrees Celsius (space velocity
below 20,000 hr.sup.-1) followed by the measurement of CO.sub.2
concentration in the gas stream. The assumption that full catalytic
combustion of the reductants took place is validated by the fact
that very low CO concentrations are measured. In addition, deep
oxidation of reductants provided the C1 (ppm of molecular carbon)
equivalent number (equal to CO.sub.2 concentration, in ppm), which
allows for the computation of the C1/NO ratio.
[0095] As used herein, the terms "may" and "may be" indicate a
possibility of an occurrence within a set of circumstances; a
possession of a specified property, characteristic or function;
and/or qualify another verb by expressing one or more of an
ability, capability, or possibility associated with the qualified
verb. Accordingly, usage of "may" and "may be" indicates that a
modified term is apparently appropriate, capable, or suitable for
an indicated capacity, function, or usage, while taking into
account that in some circumstances the modified term may sometimes
not be appropriate, capable, or suitable.
[0096] Reference is made to substances, components, or ingredients
in existence at the time just before first contacted, formed in
situ, blended, or mixed with one or more other substances,
components, or ingredients in accordance with the present
disclosure. A substance, component or ingredient identified as a
reaction product, resulting mixture, or the like may gain an
identity, property, or character through a chemical reaction or
transformation during the course of contacting, in situ formation,
blending, or mixing operation if conducted in accordance with this
disclosure with the application of common sense and the ordinary
skill of one in the relevant art (e.g., chemist). The
transformation of chemical reactants or starting materials to
chemical products or final materials is a continually evolving
process, independent of the speed at which it occurs. Accordingly,
as such a transformative process is in progress there may be a mix
of starting and final materials, as well as intermediate species
that may be, depending on their kinetic lifetime, easy or difficult
to detect with current analytical techniques known to those of
ordinary skill in the art.
[0097] Reactants and components referred to by chemical name or
formula in the specification or claims hereof, whether referred to
in the singular or plural, may be identified as they exist prior to
coming into contact with another substance referred to by chemical
name or chemical type (e.g., another reactant or a solvent).
Preliminary and/or transitional chemical changes, transformations,
or reactions, if any, that take place in the resulting mixture,
solution, or reaction medium may be identified as intermediate
species, master batches, and the like, and may have utility
distinct from the utility of the reaction product or final
material. Other subsequent changes, transformations, or reactions
may result from bringing the specified reactants and/or components
together under the conditions called for pursuant to this
disclosure. In these other subsequent changes, transformations, or
reactions the reactants, ingredients, or the components to be
brought together may identify or indicate the reaction product or
final material.
[0098] In describing, the products of the instant invention as a
reaction product of initial materials reference is made to the
initial species recited and it is to be noted that additional
materials may be added to the initial mixture of synthetic
precursors. These additional materials may be reactive or
non-reactive. The defining characteristic of the instant invention
is that the reaction product is obtained from the reaction of at
least the components listed as disclosed. Non-reactive components
may be added to the reaction mixture as diluents or to impart
additional properties unrelated to the properties of the
composition prepared as a reaction product. Thus for example finely
divided solids such as pigments may be dispersed into the reaction
mixture, before during or after reaction to produce a reaction
product composition that additionally comprises the non-reactive
component, e.g. the pigment. Additional reactive components may
also be added; such components may react with the initial reactants
or they may react with the reaction product; the phrase "reaction
product" is intended to include those possibilities as well as
including the addition of non-reactive components.
[0099] The embodiments described herein are examples of
composition, articles, systems and methods having elements
corresponding to the elements of the invention recited in the
claims. This written description may enable those of ordinary skill
in the art to make and use embodiments having alternative elements
that likewise correspond to the elements of the invention recited
in the claims. The scope of the invention thus includes articles,
systems and methods that do not differ from the literal language of
the claims, and further includes other articles, systems and
methods with insubstantial differences from the literal language of
the claims. While only certain features and embodiments have been
illustrated and described herein, many modifications and changes
may occur to one of ordinary skill in the relevant art. The
appended claims cover all such modifications and changes.
* * * * *