Title of Invention

GOLDCATALYST ON CERIA-CONTAINING SUPPORT

Abstract Goldcatalyst, characterized in that the gold is supported on ceria, wherein the ceria is a Ce1-xMnxO2 support which contains the elements in the ratio Ce: Mn=10:1 to 1:1 and in which the ceria is a polycrystalline cerium oxide powder in the form of aggregates of primary particles, with a specific surface of between 20 and 200 m2/g,an average primary particle diameter of between 5 and 20 nm, and an average, projected aggregate diameter of between 20 and 100 nm.
Full Text GOLDCATALYST ON CERIA-CONTAINING SUPPORT
The subject of the invention is a goldcatalyst, a method
for its production and its use.
Gold with a large particle size has been regarded as a
poorly active catalyst.
A theoretical calculation has explained the smooth surface
of Au is noble in the dissociation adsorption of: hydrogen
(Hammer and Norskov, 1995).
However, when Au is deposited on nanoparticlcs like metal
oxides by means of coprecipitation and deposition-
precipitation techniques, it exhibits surprisingly high
catalytic activity for CO oxidation at a temperature as low
as 200 K (Haruta et al. 1989; Haruta and Date, 2001). This
finding has motivated many scientists and engineers to
investigate in the catalysis of Au since 1990.
Many excellent reviews have been reported (Bond and
Thompson, 1999; 2000; Cosandey and Madey, 2001; Ko/.lov et
al., 1999; Haruta, 1997a, b; Haruta and Date, 2001;
Okumura, 1999) .
The selective removal of CO in a hydrogen rich gas under
ambient conditions has been of considerable technical
interest for purification of hydrogen rich gas, e.g. for H2
supply in ammonia synthesis for a long time.
In recent years, this technology has attracted new interest
due to its use in fuel cell technology.
Polymer electrolyte membrane fuel cells (PEMFC), in
particular in vehicle applications, operate at relatively
low temperatures, usually at 80-120 °C.
When hydrogen rich fuel is produced from methanol or
gasoline on board by partial oxidation and steam reforming

combined with water gas shift reaction, the Pt anodes at.
these low temperatures are often poisoned by incomplete
combustion produces, mainly CO, reducing the overall fuel
cell performance. Under normal running conditions, the
product hydrogen stream contains approximately 7 5 vol.% II2,
25 vol.% CO2, a few vol.% H2O, and 0.5-1.0 vol.% CO.
Thus in order to obtain optimum performance for the fuel
cell vehicles, the total concentration of CO in the gas
stream should be reduced, if possible, to below 10C ppm.
Metal oxide-supported nanosized gold catalysts are very
active for CO oxidation at low temperature. The suitable
supports are the metal oxides which can bo partially
reduced, such as TiO2, Fe2O3, CO3O4, etc..
CeO2 was used as a support because of its high oxygen
storage capacity. Although several ceria-supported
catalysts were reported before, most of their loading
metals were not gold or different methods were used to
prepare the catalysts.
CeO2 has been used as the support for platinum (Holgado and
Munuera, 1995), palladium (Yee et al., 1999), rhodium (Yee
et al., 2000) and copper oxide (Avgouropouios ot a.1.,
2002) .
Antonucci et al. (2004) prepared the CeO2 supported gold
catalysts by coprecipitation method and used if on
selective CO oxidation.
Osuwan et al. (2004) also prepared the gold/cerium oxide
catalysts by three methods, co-precipitation, impregnation
and sol-gel, and used it on water-gas shift: reaction.
Hutchings et al. (1998) investigated in detail the effect
of preparation conditions on copper containing catalysts,
Cu-Mn-0 catalysts, on the performance of catalytic removal
of CO.

Another type of catalysts proposed for selective CO
oxidation were noble metals, such as platinum, ruthenium
and rhodium, supported on alumina and zeolite.
The Freni et al. (2000) investigation showed that Ru/Al2O3
and Rh/Al2O3 catalysts had higher selectively and
reactivity for catalytic removal by oxidation of CO
compared with a Pt/Al2O3 catalyst.
Lee et al. (1998) studied the catalytic performance of
removal of CO by the selective catalytic oxidation method
based on Pt/Al2O3 and A-zeolite, respectively.
Kahlich et al. (1997) investigated the kineuies of
selective CO oxidation on Pt/Al2O3.
Dong et al. (1997) investigated the performance of
oxidation of CO over supported PdCl2-CuCl2 catalysts, and
also studied the effect of small amounts of impurities,
such as HCl and SO2, on the catalyst performance.
Avgouropoulos et al. (2002) compared the Pf/r-Al203, Au/a-
Fe2O3 and CuO-CeO2 catalysts for the selective ox.i.da t.i.on of
CO in hydrogen rich gas. The Au/a-Fe203 catalyst is
superior to the other two for the reaction at relatively
low reaction temperatures ( contact time and feed composition employed), while at
higher reaction temperatures, best results are obtained
with the CuO-Ce02 catalyst, which proved to be more active
and remarkably more selective than the Pt/r-Al203 catalyst.
The Au/a-Fe203 catalyst was the most sensitive, while the
Pt/r-Al203 the most resistant towards deactivation caused
by the presence of C02 and H20 in the feed, in addition,
the Au/a-Fe203 lost a considerable portion of its activity
during the first 80 h under reaction condition, the CuO-
Ce02 and Pt/r-Al203 catalysts exhibited a stable catalytic
performance, at least, during the time-period of 7-8 days.

In contrast, Cameron (2003) reported that Au/a-Fo^O.-j is
much more reactive than Pt/r-Al203.
Several literatures have been reported about selective CO
oxidation as shown in table 3.
It is found that most gold/ceria oxide catalysts do not
show very high activities below 100 °C which is better for
PROX reaction.
The cited references are published in
Hammer, R. and Norskov, J.K., Nature 376 (1995) 238.
M. Haruta, N. Yamada, T. Kobayashi, S. I.ijima, J. Catai.
115 (1989) 301
Dong, J.K., Jae, H.S., S.H. Hong, I.S. Noon, Korean J.
Chem. Eng. 14 (1997) 486-490.
Kahlich, M.J., Gasteiger, H.A., Behm, R.J'., J. Catai. 171
(1997) 93-105.
Hutchings, G.J., Mirzaei, A.A., Joyner, R.W., Appl. Cata.l .
166 (1998) 143-152.
Lee, C, Yoom, H.K., Moon, S.H., Yoom, K.J., Korean J.
Chem. Eng. 15 (1998) 590-595.
Bond, G.C. and Thompson, D.T., Catai. Rev.-Sci. F,ng. 41
(1999) 319.
Kozlov, A.I., Kozlova, A.P., Liu, H., and Iwasawa, Y.,
Appl. Catai. A: General 182 (1999) 9-28.
Okumura, M., "Report of the Research Achievement of
Interdisciplinary Basic Research Scetion: No. 3 93", Osaka
National, research Institute, 1999, 6.
Freni, S., Calogero, G., Cavallaro, S., J. Power Sources 87
(2000) 28-38.
Cosandey, F. and Madey, T.E., Surf. Rev. Lett 8 (2001) 73.

Haruta, M. and Date, M., , Appl. Catal. A: Genera.1 222
(2001) 427-437.
R. J. H. Grisel, C. J. Westrstrate, A. Goosscns, M. W. J.
Craje, A. M. van der Kraan, and R. E. Nieuwenhuys, Catal.
Today 72, 123 (2002)
J. P. Holgado, G. Munuera, XPS/TPR study of the
reducibility of M/Ce02 catalysts (M=Pt, Rh): Does junction
effect theory apply? Elsevier Science, Brussels, Belgium,
1995.
A.Yee, S. J. Morrison, H. Idriss, J. Catal. 186 (1999) 279.
A. Yee, S. J. Morrison, II. Idriss, Catal. Today 63 (2000)
327.
Avgouropoulos, G., Ioannides, T., Papadopoxilou, C,
batista, J., Hocevar, S., and matralis, catal. Today 7b
(2002) 157-167.
A. Luengnaruemitchaia, S. Osuwana, E. Gu.larib,
International Journal of Hydrogen Energy 29 (2004) 429 -■
435.
Cameron, D., Corti, C, Holliday, R., and Thompson, D.,
"Gold-based catalysts for hydrogen processing and fuel cell
systems", adapted from web site of world godl council,
www.wgc.org. (2003) .
M. Haruta, Journal of New Materials for Electrocnomical
Systems 7, 163-172 (2004)

The subject of the invention is a goldcatalyst,
characterized in that the gold is supported on ccria.
In a preferred form of the invention the ceria is a
polycrystalline cerium oxide powder in the form of
aggregates of primary particles, which has
a specific surface of between 20 and 200 m2/g,
an average primary particle diameter of between 5 and
20 nm, and
an average, projected aggregate diameter of between 2 0
and 100 nm.
The ceria can be a Cei-xMnx02 support. The Cei-xMnxC>2 support;
can contain the elements in the ratio Ce:Mn 10:1 to 1:1.
The Cei-xMnxC>2 support can be prepared via the impregnation
method, whereby a solution of a Mn-salt is added to -„he
CeO? powder and the impregnated CeC>2 powder is then
calcined.
The calcination can be made at a temperature of 35 0 °C to
450 °C for a time of up to 3 hours.
The ceria used according to the invention can bo a known
ceria, i.e. the ceria that is disclosed in EP 1506940A1
(=US 2005/036928A1) or that is disclosed in the German
patent application DE 102005344, filed on February 5, 2005.
According to DE 102005344 the ceria can be produced by a
process by reacting an aerosol with oxygen in a reaction
space at a reaction temperature of more than 700°C and then
separating the resulting powder from the gaseous
substances, wherein

- the aerosol is obtained by atomisation of at. least one
starting material, as such in liquid form or in
solution, and at least one atomising gas by means of: a
multi-component nozzle,
the volume-related mean drop diameter D30 of the
aerosol is from 30 to 100 |J,m and
the number of aerosol drops larger than 10 0 |i.m is up
to 10%, based on the total number of drops.
The volume-related mean drop diameter D30 is calculated by:

A starting material is to be understood as being a cerium
compound which is converted under the react.ion conditions
into a cerium oxide.
It is possible to produce cerium oxi.de powders having a
large surface area if the volume-related mean drop diameter
D30 is from 30 to 100 |lm and at the same time up to 10% oi
the drops are absolutely larger than 100 |_im. It is possible
as a result to increase the throughput of solution compared
with the prior art without having to accept a marked
reduction in the BET surface areas of the powders. The H1;!T
surface area of the powders obtained by the process
according to the invention is at least 20 m2/g, preferably
from 20 to 200 m2/g.
The absolute drop size is determined according to the
principle of dual phase-Doppler anemometry using a 5W
argon-ion continuous-wave laser.
In a preferred embodiment, the number of drops, based on
the total number of drops, larger than 100 u.m may be from
3% to 8%.

Furthermore, it may be advantageous if the percentage of
drops larger than 250 jLlm is not more than 10%, based on the
number of drops > 100 )J.m.
In particular, an embodiment may be advantageous in which
the following dependence of the volume-related moan drop
diameter D30 on the spray width of the aerosol applies:

The throughput of a solution containing a starting material
may be preferably from 3.5 to 2000 kg/h and particularly
preferably from 100 to 500 kg/h.
The content of starting material in the solution may be
from 2 to 60 wt.%, preferably from 5 to 40 wt.%.
The starting materials may be organometallic and/or
inorganic in nature; preference may be given to
organometallic compounds. Examples of inorganic starting
materials may be in particular cerium chlorides and cer.i urn
nitrates. There may be used as organometallic compounds
especially cerium alcoholates and/or cerium earboxylatos.
There may bo used as alcoholates preferably othoxi.dos, n-
propoxides, isopropoxides, n-butoxides and/or tort. .-■
butoxides. As carboxylates there may be used the compounds
underlying acetic acid, propionic acid, butanoio acid,
hexanoic acid, oxalic acid, malonic acid, succinic acid,
glutaric acid, adipic add, octanoic acid, 2-ct.hyihexanoic
acid, valeric acid, capric acid and/or lauri.e acid. 2-
ethylhexanoates and/or laurates may particularly
advantageously be used.

Inorganic starting compounds may preferably be dissolved in
water; organometallic starting compounds may preferably be
dissolved in organic solvents.
As organic solvents, or as a constituent of organic solvent
mixtures, there may be used preferably alcohols such as
methanol, ethanol, n-propanol, isopropanol, n-butanol or
tert.-butanol, diols such as ethanediol, pentanedioi, 2-
methyl-2,4-pentanediol, dialkyl ethers such as diethyl
ether, tert.-butyl methyl ether or tetrahydrofuran, Ci-Oi?-
carboxylic acids such as, for example, acetic acid,
propionic acid, butanoic acid, hexanoic acid, oxalic acid,
malonic acid, succinic acid, glutaric acid, adipic acid,
octanoic acid, 2-ethylhexanoic acid, valeric acid, capric
acid, lauric acid. There may further be used ethyl acetate,
benzene, toluene, naphtha and/or benzine. Preference is
given to the use of solutions containing Cz-Cu-carboxylic
acids, in particular 2-ethylhexanoic acid and/or lauric
acid.
Preferably, the content of C2-Ci2-carboxylic acids in the
solution is less than 60 wt.%, particularly preferably .less
than 40 wt.%, based on the total amount of solution.
In a particularly preferred embodiment, t.he solutions of
the starting materials contain at the same time a
carboxylate and the underlying carboxylic acid and/or an
alcoholate and the underlying alcohol. In particular, there
may be used as starting materials 2-ethylhexanoates in a
solvent mixture that contains 2-ethylhexanoic acid.
There may be used as a reactive gas such as air, air-
enriched with oxygen and/or an inert gas such as nitrogen.
In general, air is used as the atomising gas.
With regard to the amount of atomising gas, the ratio
throughput of the solution of the starting material /

amount of atomising gas is preferably from ?. to 25 kg/NmJ
and particularly preferably from 5 to 10 kg/Nm .
Suitable multi-component: nozzles are especially three-
component nozzles or four-component nozz3.es.
When three-component nozzles or four-component nozzles are
used it is possible to atomise, in addition to the
atomising gas, two, or three, separate solutions which
contain
- the same or different starting materials,
- in the same or different solvents,
- in the same or different concentrations.
It is thus possible, for example, simultaneously to atomise
two solutions having different concentrations of a starting
material with the same solvent or solvent mixture. Aerosol
drops of different sizes are thereby obtained.
It is also possible, for example, for the atomising qas to
be supplied via two nozzles or for different atomising
gases to be used, for example air and steam.
Separate solutions of different starting materials can be
used to produce mixed oxide powders.
The reaction temperature of more than 700°C can preferably
be obtained by means of a flame produced by react ion of a
hydrogen-containing combustion gas with (primary) air,
optionally enriched with oxygen. Suitable combustion gases
may be hydrogen, methane, ethane, propane, butane and/or
natural gas, with hydrogen being particularly preferred.
The reaction temperature is defined as the temperature 'chat
is established 0.5 m below the flame.
It may further be advantageous if secondary air is
additionally introduced into the reaction space. In
general, the amount of secondary air will be such that the
ratio of secondary air to primary air is from 0.1 t.o 10.

It is particularly advantageous if lambda is > 1.5, lambda
being calculated from the quotient of the sum of the oxygon
content in the air used (primary air, secondary air and
atomising air) divided by the sum of the starting materials
and the hydrogen-containing combustion gas, in each case in
mol./h. Very particularly preferably, 2 Separation of the powder from the reaction mixture is
generally preceded by a cooling process. This process may
be carried out directly, for example by means of a
quenching gas, or indirectly, for example via external
cooling.
The cerium oxide powder may contain impurities resulting
from the starting material and/or the process. The purity
of the annealed cerium oxide powder is at least 98 wt.%,
generally at least 99 wt.%. A content of at least 99.8 wt.%
may be particularly preferred.
In general, the cerium oxide powder is predominantJy or
exclusively in the form of aggregates of primary particles,
the aggregates exhibiting no cenospherical structures. A
cenospherical structure is to be understood as being a
structure that has a size of from 0.1 to 2.0 urn and it
approximately in the form of a hollow sphere, with a wal1
thickness of from 0.1 to 2 jam. Predominantly is to be
understood as meaning that a TEM picture shows individual
non-aggregated particles in an amount of not more than 10%.
The cerium oxi.de powder may preferably have a BET surface
area of from 30 to 200 m2/g.
The content of coarse particles > 45 u.m in the cerium oxide
powder is preferably less than 100 ppm and particularly
preferably less than 50 ppm.
The cerium oxide powder preferably has a carbon content of
less than 0.15 wt.% and a content of chloride, sodium and
potassium of less than 300 ppm.

The cerium oxide powder may preferably be a cerium oxide
powder having a BET surface area of from 30 Lo 90 m'7g.
The cerium oxide powder when exposed to air ana
temperatures of 900°C for a period of two hours, may have a
BET surface area of up :.o 35 m2/g.
The mean primary particle diameter of the cerium ox.i.de
powder may be preferably from 5 to 2 0 nm and particularly
preferably from 8 to 14 nm.
The mean aggregate diameter of the cerium oxide powder may
be from 20 to 100 nm and particularly preferably from 30 to
7 0 nm.
The ceria can be a polycrystalline cerium oxide powder in
the form of aggregates of primary particles, which is
characterised in that
a specific surface of between 20 and 200 m2/g,
an average primary particle diameter of between 5 and
20 nm, and
an average, projected aggregate diameter of between 20
and 100 nm.
As used herein, the term "polycrystalline" means that Lhe
primary particles are crystalline and fused into
aggregates. The term "primary particles" means particles
that are initially formed in the reaction and fuse together
to form aggregates as the reaction progresses. The term
"aggregate" means primary particles of similar structure
and size that have fused together, the surface of wnich is
smaller than the sum of the individual, isolated primary
particles.

The average primary particle diameter and the average
projected aggregate diameter (ECD; Equivalent Circle
Diameter) are obtained by image analysis of TEM
photographs. Both sizes are defined as number-based within
the meaning of the application.
A powder with a specific surface of between 90 and 120 mVg
may be preferred.
The average primary particle diameter can be between 8 and
15 nm and the average projected aggregate diameter between
3 0 and 7 0 nm.
It has proved advantageous for the primary particle
diameters to have a narrow distribution. This means that,
for an average value m of the diameter, at least 68% of the
particles are in the range of 0.6 m to 1.4 m or 95% of the
particles are in the range of 0.2 m to 1.8 m. For an
average primary particle diameter of 10 nm, this means that
at least 68% of the particles are in a range of between 6
and 14 nm, or 95% of the particles are in a range of
between 2 and 18 nm.
Similarly, it is advantageous if the aggregate diameters
have a narrow distribution. This means that, for an average
value m of the projected aggregate diameter, at. least 68%
of the projected aggregate diameters are in the range of
0.6 m to 1.4 m or 95% of the particles are in the range of
0.2 m to 1.8 m. For an average, projected aggregate
diameter of 40 nm this means that at least 68% of the
particles are in a range of between 24 and 5 6 nm, or 95% of
the particles are in a range of between 8 and 72 nm.
Preferably at least 70%, particularly preferably at least.
80% of the aggregates of the cerium oxide powder according
to the invention can have an area of less than 1500 r.m'.
It is also preferred that at least 85%, particularly
preferably at least 90%, of the aggregates of the cerium

oxide powders according to the invention have an area 01
less than 4500 nm2.
In another embodiment, the cerium oxide powder according to
the invention can have a composition CeOx with x=-l . 5 the surface, wherein the range 1.7 particularly preferred. This means that areas of
cerium(III) oxide (Ce203) and cerium(IV) oxide (CeOz) are
present on the surface. This composition may be important
particularly in the field of catalysis (oxygen storage,
oxygen generation).
The cerium oxide powder according to the invention can have
a total sodium content of less than 500 ppm, particularly
preferably of less than 100 ppm, especially preferably less
than 3 0 ppm.
In a particular form, the cerium oxide powder according to
the invention can have less than 10 ppm on the surface and
on layers of the particles close to the surface. This can
be determined e.g. by large-area (1 cm2) XPS analysis
(XPS--=X-ray induced photoelectron spectroscopy) . A layer
close to the surface means a surface produced by ion
bombardment (5 keV argon ions).
In addition, the cerium oxide powder according to ~hc
invention can have a carbon content of less than 0.1 wt.-%,
particularly preferably of less than 0.05 wt.-%. Sources of
carbon are mainly organic cerium oxide precursors and
organic solvents.
In one embodiment, the cerium oxide powder according to the
invention is free from micropores with a pore dlamot.or of.
less than 2 nm, determined by t-plot according to de Boer.
The volume of the mesopores with a diameter of between 2
and 50 nm in the cerium oxide powder according to the
invention can be between 0.40 and 0.60 ml/g, particularly
preferably between 0.4 5 and 0.55 ml/g.

The mesopores in the cerium oxide powder according to the
invention preferably exhibit a monomodal size distribution.
This means that, when the pore volume is plotted against
the pore diameter, no marked maximum (point without slope)
occurs in the range between 2 and 50 nm. The pore volume
thus increases constantly with the pore diameter.
The invention further provides a process for the production
of the cerium oxide powder according to the invention,
which is characterised in that an aerosol is reacted in a
flame bxarning in a reaction chamber and the solid obtained
is then separated from the gaseous substances, wherein
the aerosol is produced from an atomizer gas, preferably
air, and a solution containing between 2 and 40 wt.-% of
a cerium compound that can be converted to cerium oxide
by oxidation,
the flame is obtained from a hydrogen-containing
combustible gas and primary air, which can be air itself
or an air/oxygen mixture,
at least the same quantity of secondary air as primary
air is introduced into the reaction chamber,
for lambda, it is true that 1.1 lambda being calculated from the quotient of: the sum of
the proportion of oxygen in the primary air, the
secondary air and the atomizer gas, if if contains
oxygen, divided by the sum of the cerium compound to be
oxidised and the hydrogen-containing combustible gas,
each in mol/h,
the discharge velocity of the liquid droplets from the
atomizer unit into the reaction chamber is greater than
50 0 m/s, and
the velocity of the reaction mixture in the reaction
chamber is greater than 2 m/s.

The cerium oxide powder according to the invention is
obtained by a combination of the above-mem.ioned features.
If individual features lie outside the limits claimed, this
leads to a cerium oxide powder with an unfavorable, large
aggregate diameter and/or to the formation of a coarse
portion. A composition of this type cannot be tolerated
e.g. when the cerium oxide powder is to be used as an
abrasive in the semiconductor industry.
The proportion of the cerium compound in the solution is
between 2 and 40 wt.-% in the process according to the
invention. Lower values make no sense economically, and
with higher values there can be problems with the
solubility. It can be advantageous to select a proportion
of the cerium compound in the solution of between 5 and 25
wt.-%.
The nature of the solvent, whether aqueous, organic or
aqueous-organic, is not limited in the process according to
the invention. It is dependent on the solubiifty of the
cerium compounds used. However, it may be advantageous to
use an organic solvent or mixtures of organic solvents with
water. For example, alcohols such as ethanol, propano.ls or
butanols or carboxylic acids such as acetic acid, propionic
acid, 2-ethylhexanoic acid can be used. Halogen-containing
solvents can also be used, but they mean that, product
purification steps are additionally necessary and so they
are less advantageous.
The nature of the cerium compounds used in the process
according to the invention is not limited. Organic cerium
compounds can preferably be used. These can be, for
example, cerium alkoxides, such as cerium isopropylate,
cerium acetate, cerium acetylacetonate, cerium oxalate,
cerium 2-ethylhexanoate and mixtures of the above. Cerium
2-ethylhexanoate can particularly preferably be used.

The solution can be fed in under a pressure of 1 tc 1000
bar, preferably between 2 and 100 bar.
The atomization of these solutions can be performed e.g. by
ultrasonic atomizer or at least one multi-substance nozzle.
The multi-substance nozzle can be used at pressures of up
to 100 bar. When a multi-substance nozzle is used, there is
the advantage that the droplets can be produced with a gas
jet. If this gas jet contains oxygen, a very Intensive
premixing of the oxidising agent with the cerium-containing
compound can be achieved. A mist eliminator can
advantageously be connected-downstream.
An essential feature of the process according to the
invention is the maintaining of the factor lambda, which,
in the process according to the invention, is between 1.1.
and 1.5. Outside this range, no cerium oxide powder
according to the invention is obtained. With lower lambda
values, there is the risk of incomplete oxidation, and with
higher lambda values, mainly powders containing a coarse
portion result. A lambda value of between 1.2 and 1.5 has
proved advantageous.
A coarse portion is also obtained if the discharge velocity
of the liquid droplets from the atomizer unit into the
reaction chamber and the velocity of the reaction mixture
in the reaction chamber lie outside the claimed limits.
The term "coarse portion" as used herein refers to
particles with an average diameter of more than 1.00 run.
Another important feature of the process according to the
invention is the quantity of secondary air introduced into
the reaction chamber. This must at least correspond to the
quantity of primary air to obtain the cerium oxide powder
according to the invention. If smaller quantities of
secondary air are fed in, an increased proportion of coarse
portions must again be expected. A process in which double

the quantity of primary air is fed in as secondary air has
proved advantageous.
It can also be advantageous if a restr.ict.or is provided in
the reaction chamber. This can be positioned at, various
points in the reaction chamber. With this, the degree of
mixing of the reaction components, and the velocity
thereof, can be intensified. In general, a turbulent flow
will be particularly preferred.
The process according to the invention can be carried out
in such a way that the reaction mixture is cooled to
temperatures of 100 to 200 °C after leaving the reaction
chamber. This can be achieved by introducing water vapor
into the reaction chamber at one or more points.
The separation of the solid from gaseous products is not
limited in the process according to the invention. For
example, a cyclone or a filter can be used. It has proved
particularly advantageous to use a heatable filter. The
temperature of this filter ca-n preferably be between
100 °C. and 200 °C.
The temperature in the reaction chamber, measured 0.5 in
below the flame, can preferably be between 1000 °C and
1400 °C, particularly preferably between 1100 °C and
1250 °C.
The goldcatalyst according to the invent.ion can be produced
by the method, which is characterized in that, a solution of
a gold salt i.e. HauCl4 is added into a solution, which
contains the suspended support, whereby the temperature is
maintained at 60 to 70 °C, after aging a time the
precipitate is filtered and washed until no Cl-ions were
detected, dried and then calcined.
The drying can be made at a temperature of 70 to 9G "C.

The calcination can be made by a temperature of IOC to
2 00 °C.
The goldcatalyst according to the invention can be used for
the oxidation of Co in a II2-stream.
Examples according to ceria
The specific surface is determined in accordance with DIN
66131, incorporated herein by reference.
The TEM photographs are obtained with a Hitachi TF,M
instrument, model H-75000-2. Using the CCD camera of the
TEM instrument and subsequent image analysis, approx. 2000
aggregates are evaluated in each case with respect to the
primary particle and aggregate diameters.
The surface properties, such as sodium content and
stoichiometry of the cerium oxide powder, are determined by
large-area (1 cm2) XPS analysis (XPS=X-ray induced
photoelectron spectroscopy).
The stoichiometry of the cerium oxide powder here is
determined on the surface in the original state based on
the fine structures of the Ce 3d5/2 and 3d3/2.
The sodium content is determined both in the origina.l state
and after 30 minutes surface erosion by ion bombardment (5
keV argon .ions) .
Sodium content (wet chemical): decomposi t.i on with H^SC^/HF,
determination by ICPMS.
The pore size distribution is determined for micropores ( nm) by t-plot according to de Boer, for mesopores (2-50 nm)
by the BJH method and for macropores (>h0 nm) by Hg
intrusion.

The dispersions are produced by ultrasonic treatment;
ultrasound probe (Bandelin UW2200/DH13G), step 8, 100%; 5
minutes) in water. The average aggregate diameters d:;0 of
the cerium oxide powders are determined with an LB--50 0
particle size analyzer from Iloriba.
Example 1
1200 g/h of a solution of cerium (III) 2-ethylhexanoat.e
(49 wt.-%) in 2-ethylhexanoic acid (51 wt.-%) are atomized
through a nozzle with a diameter of 0.8 mm into a reaction
chamber using air (5 m3/h). Here, an oxyhydrogen gas flame
consisting of hydrogen (10 m3/h) and primary air (10 mJ/h)
is burning, in which the aerosol is reacted. In addition,
20 m3/h of secondary air are introduced into the reaction
chamber. A restrictor with a length of 150 mm and a
diameter of 15 mm, through which the reaction mixture is
passed, is installed in the reaction chamber below the
flame. After cooling, the cerium oxide powder is separated
from gaseous substances using a filter.
Examples 2-4
Examples 2 to 4 are performed in the same way as Example 1;
the quantities used and other process parameters can be
taken from Table 1. In Example 5, no restrictor is employed
and cerium(III) nitrate is used instead of cerium(III) 2-
ethylhexanoate.
The physico-chemical data of the cerium oxide powders
obtained can be taken from Table 2.
The naming of the dispersions corresponds to the relevant
powders. Dispersion Dl corresponds to the powder PI from
Example 1, D2 corresponds to P2, etc..






Deposition-precipitation method was used to prepare Au/Ce02
and Au/CexMni-x02 catalyst. CO oxidation reaction at room
temperature and selective CO oxidation reaction in hydrogen
stream at various temperatures were used to test the
activity of catalyst.
Preparation of support
Two kinds of supports were used in this study, CeG2 and Ce-
Mn-02Ce02 was from Degussa AG. Cei-xMnx02 support was
prepared by impregnation method. Mn(N03)2 was added into
distilled water equal-volume to Ce02 we Look. The solution
was added into Ce02 powder dropwise under vigorous
grinding. After calcining for two hours at 4 0 0 °C for 2
hours, The Cei-xMnx02 could be obtained. The sample C-
(10*x)Mn means that the support is Cei-xMnx02 - For example,
C-IMn means that the support is Ceo.9Mno.1O2.
The Ce02 from Degussa AG has the following chemical-
physical datas :

Preparation of gold catalysts
HAuCl4 solution (1 g in 1 liter distilled water) was added
with the rate 10 ml/min into the solution containing
suspended support under vigorous stirring and the
precipitation temperature of solution was maintained at 60
to 70 °C. The ammonia solution was used to adjust the pll
value at 8. After aging for 2 hours, the precipitate was
filtered and washed with hot water until no CI" was
detected with AgNC>3 solution, then was dried at 80 °C
overnight. The cake was calcined at 120 and 180 °C for
several hours to obtain gold catalysts.
Characterization results
BET surface area
The surface areas of supports contained manganese were
measured by ASAP 2010. The results are listed in Table 1.
Addition of manganese decreased the surface area of CeOz.


XRD
Figure 1 shows the XRD patterns of gold catalysts calcined
at different temperatures on Adnano Ceria 90.
Figures 2 and 3 show the XRD patterns of C-IMn and C-5Mn
supports and gold catalysts. It was found that no gold
peaks (2q=3 8.2° and 4 4.5°) were detected no matter what the
calcination temperature was. It is because that the
particle size of gold is too small to detect ( result is well consisted with the TEM images as discussed
in the later section. Weil crystalline CeOz were also
detected in XRD patterns. It should be notice that Figure 3
shows a small peak at 2q=- 37.3°, this is due to the (1,0,1)
phase of Mn02.
TEM
Figure 4 shows the TEM image and size distribution of gold
of gold catalysts supported on Adnano Ceria 90 and calcined
at 120 and 180 °C, respectively. It was found that, the
particle size of gold are about 2-4 nm and the particle
size of Ceria support is about 10-20 nm. No obvious
relationship between the Au particle size and the
calcination temperature of gold was found.

Figures 5 and 6 show the TEM images and size distributions
of gold for catalysts supported on C-IMn and C-bMn and
calcined at 120 and 180 °C, respectively. The results are
the same. It means that the particle size would be similar
when the preparation method is the same.
XPS
XPS analysis was used to determine the oxidation state of
gold in this study.
Figures 7-9 show the XPS spectra of gold. It was found that
the peaks of catalysts calcined at 180 °C are more
separated than 120 °C. It means that more metallic gold was
appeared at that temperature. The results are in accordance
with literatures (Neri et al., 2003; Bowker et a.l. , 2003).
Reaction test
CO oxidation
Catalytic activity was measured with a fixed bed continuous
flow reactor. Samples were placed in a class column, and no
pretreatment was applied in this test. 0.0b cm3 catalysts
were used. The reactant gas containing 1000 ppm CO, 2 %C>2
and N2 else was admitted at the flow rate of 50 cc/min
through the reactor. The flow rates were monitored by mass
flow controllers. The reaction was occurred at room
temperature (25 °C) . A CO sensor was used to do fee-; the
output CO concentration. The CO conversion was calculated
with the following equation:

Selective CO oxidation in H2 stream
The catalytic activity was measured in a glass downward,

fixed-bed continuous-flow reactor, with 0.1 cmJ catalysts.
The reactant gas containing 1.33 % CO, 1.33 % 02,
65.33 % H2 and He for balance was guiding into the reactor
with the flow rate of 50 cc/min. The reactor was headed
with a regulated furnace (heating rate: 1 °C/min) ana i.he
temperature was measured by thermocouple placed inside the
catalysts bed. The outlet gas was analyzed by a gas
chromatography equipped with a thermal conductivity
detector. The GC column was MS-5A. Calibration was done
with a standard gas containing known concentrations of the
components. The CO conversion and selectivity were
calculated as follows:

Reaction results
CO oxidation
Figure 10 shows the result of CO oxidation reaction on gold
catalysts supported on Adnano Ceria 90 and calcined at 120
and 180 °C, respectively. Both of them showed excellent
activities. The catalyst calcined at 180 °C could fully
remove CO at room temperature. The gold catalyst calcined
at 120 °C could also remove CO more than 95%. This result
means that metallic gold is better than oxidic gold for CO
oxidation at room temperature, which is consisted with the
result reported by Haruta (1997, 2004) and Grisel (2002).

Selective CO oxidation in hydrogen stream
Figure 11 shows the catalytic activities of gold catalysts
supported on Adnano Ceria 90 and calcined at 120 and
180 °C, respectively. It is interesting that when the
reaction temperature was below 50 °C, the catalyst calcined
at 180 °C was more active than those calcined at 12 0 "C . In
contrast, if the reaction temperature was above 50 °C , the
catalyst calcined at 120 °C was more active. It shouid be
noted that oxygen in this study was fully consumed at. the
temperature greater than 50 °C no matter what catalyst was
used. This suggests that hydrogen is easier to react with
oxygen at higher temperature under the existence of
metallic gold.
Figure 12 shows the reaction results of gold catalysts
supported on Ce-Mn-0. It is found that the catalytic
activities at 80 °C, which is the most suitable temperature
for PROX reaction in fuel cell, increased with the addition
of manganese in Ceria. The catalysts calcined at 120 °C
with more oxidic gold showed higher activi ties at high
temperature. This is the same with gold supported en Adnano
Ceria 90.
Table 2 lists the reaction results.
Table 3 shows the results according to the art.





List of the figures
Figure 1 .
The XRD patterns of
(a) l%Au-18 0/Adnano Ceria,
(b) l%Au-120/Adnano Ceria and
(c) Adnano Ceria
(Au-180 means the catalyst was calcined at 180 degree
Celsius.)
Figure 2.
The XRD patterns of
(a) C-IMn,
(b) l%Au-120/C-lMn and
(c) l%Au-18 0/C-lMn.
Figure 3.
The XRD patterns of
(a) C-5Mn,
(b) l%Au-120/C-5Mn and
(c) l%Au-180/C-5Mn.
Figure 4.
TEM images of gold catalysts calcined at different.
temperatures supported on Adnano Ceria.
Figure 5.
TEM images and size distribution of gold of catalysts
supported on C-IMn.
Figure 6.
TEM images and size distribution of gold of catalysts
supported on C-bMn.
Figure 7.
XPS results of gold calcined at different temperatures
supported on Adnano Ceria 90.

Figure 8.
XPS results of gold calcined at different, temperatures
supported on C-lMn.
Figure 9.
XPS results of gold calcined at different temperatures
supported on C-5Mn.
CO conversion (%)
Figure 10.
CO conversion of gold catalysts supported on Adnano Ceria.
The Au catalysts were prepared by deposition-precipitation
method using NfUOH and IIAUCI4, synthesized at pH 8 and
calcined at 120 and 180 °C in air.
Catalyst sample: 0.05 cm3 of 1 wt.% Au/Ce02. Roactant gas:
1000 ppm CO, 2 % 02 and N2 for balance, 50 ml/min,
GHSV=60,000 h-1 . The catalytic activity was measured at
ambient, temperature about. 25 °C.
Figure 11.
Selective CO oxidation reaction results of gold catalysts
supported on Adnano Ceria 90 calcined at 120 and 180 °C.
The Au catalysts were prepared by deposition-precipitation
method using NH4OH and HAUCI4, synthesized at pFI 8.
Catalyst, sample: 0.1 cm3.
Reactanf gas: 1.33% C0+1.33 % 02 +65.33% II2 Hie for
balance, 50 ml/min,
GSHV-30, 000 h'1.
Figure 12.
Selective CO oxidation reaction results of gold supported
on Ce-Mn-0 and calcined at different temperatures.
The Au catalysts were prepared by deposition-precipitation
method using NH,jOH and HAuCl,-,, synthesized at pH 8.
Catalyst sample: 0.1 cm3.
Reactant gas: 1.33% CO+i.33 % 02 +65.33% H2 +He for

WE CLAIM:
1. Goldcatalyst, characterized in that the gold is supported on ceria,
wherein the ceria is a Ce1-xMnxO2 support which contains the elements
in the ratio Ce: Mn=10:1 to 1:1 and in which the ceria is a
polycrystalline cerium oxide powder in the form of aggregates of
primary particles, with
a specific surface of between 20 and 200 m2/g,
an average primary particle diameter of between 5 and 20
nm, and
an average, projected aggregate diameter of between 20 and
100 nm.
2. Method to produce the support as claimed in claim 1 characterized in
that via the impregnation method a solution of a Mn-salt is added to
the CeO2 powder and the impregnated CeO2 powder is than calcined.
3. Method to produce the goldcatalyst as claimed in claim 1 characterized
in that a solution of a gold-salt is added to a solution, which contains
the suspended support, whereby the temperature is maintained at 60
to 70 °C, after aging a time the precipitate is filtered and washed until
no C1-ions were detected, dried and then calcined.


Goldcatalyst, characterized in that the gold is supported on ceria, wherein
the ceria is a Ce1-xMnxO2 support which contains the elements in the ratio
Ce: Mn=10:1 to 1:1 and in which the ceria is a polycrystalline cerium oxide
powder in the form of aggregates of primary particles, with a specific surface
of between 20 and 200 m2/g,an average primary particle diameter of
between 5 and 20 nm, and an average, projected aggregate diameter of
between 20 and 100 nm.

Documents:

04355-kolnp-2007-abstract.pdf

04355-kolnp-2007-claims.pdf

04355-kolnp-2007-correspondence others.pdf

04355-kolnp-2007-description complete.pdf

04355-kolnp-2007-drawings.pdf

04355-kolnp-2007-form 1.pdf

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04355-kolnp-2007-pct priority document notification.pdf

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4355-KOLNP-2007-ABSTRACT.1.1.pdf

4355-KOLNP-2007-CLAIMS.pdf

4355-KOLNP-2007-CORRESPONDENCE OTHERS 1.1.pdf

4355-kolnp-2007-CORRESPONDENCE OTHERS 1.2.pdf

4355-KOLNP-2007-CORRESPONDENCE OTHERS 1.3.pdf

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4355-KOLNP-2007-CORRESPONDENCE-1.4.pdf

4355-kolnp-2007-correspondence-1.5.pdf

4355-KOLNP-2007-CORRESPONDENCE.pdf

4355-KOLNP-2007-DESCRIPTION (COMPLETE).1.1.pdf

4355-KOLNP-2007-DRAWINGS.1.1.pdf

4355-KOLNP-2007-EXAMINATION REPORT REPLY RECIEVED.1.1.pdf

4355-kolnp-2007-examination report.pdf

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4355-kolnp-2007-granted-form 1.pdf

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4355-KOLNP-2007-INTERNATIONAL EXM REPORT.pdf

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4355-KOLNP-2007-OTHERS.pdf

4355-kolnp-2007-pa.pdf

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4355-KOLNP-2007-SCHEDULE.pdf

abstract-04355-kolnp-2007.jpg


Patent Number 246518
Indian Patent Application Number 4355/KOLNP/2007
PG Journal Number 09/2011
Publication Date 04-Mar-2011
Grant Date 02-Mar-2011
Date of Filing 14-Nov-2007
Name of Patentee EVONIK DEGUSSA GMBH
Applicant Address RELLINGHAUSER STRASSE 1-11, 45128 ESSEN, GERMANY
Inventors:
# Inventor's Name Inventor's Address
1 DR. MICHAEL KRÖLL ELF MORGEN 19A 63589 LINSENGERICHT
2 MICHAEL KRÄMER DRESDENER STR. 30 61137 SCHÖNECK
3 JERRY (CHIH-YU) CHUNG 9F, 133, MIN SHENG E. RD. SEC 3 105 TAIPEI
4 PROF. YU-WEN CHEN 300 JONG-DAI ROAD 320 JUNG-LI
5 PROF. STIPAN KATUSIC KÖNIGSTEINER STR. 142 65812 BAD SODEN
PCT International Classification Number B01J 35/00
PCT International Application Number PCT/EP2006/061628
PCT International Filing date 2006-04-18
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 05011050.1 2005-05-21 EUROPEAN UNION