Abstract: Disclosed are a mixed oxide composition based on zirconium and cerium exhibiting a high reducibility, the process for preparing it and its use in the field of catalysis.

Abstract: An alumina-based adsorbent and method of making exhibiting high affinity and capacity towards fluoride ions and oxyanions of phosphorus and arsenic in a broad pH range and presence of large excess of competitive ions. Alumina based adsorbent is a mixed oxide of alumina existing in tetra-, penta-, and octahedral coordination at specific ratio, and oxides of polyvalent metals of elements titanium, zirconium, tin, cerium, lanthanum, iron, or combinations thereof. The alumina based adsorbent may be used for selective removal of fluoride ion and oxyanions of phosphorus and arsenic from drinking water, industrial streams and wastes, in medicine and food industry.

Abstract: The invention relates to a catalyst suitable for use in the hydrogenation of carbon dioxide-containing gas, said catalyst comprising spinel phase of the formula [Fe2+(Fe3+yAl3+1-y)2O4]. Processes for preparing the catalyst and processes for the hydrogenation of carbon dioxide-containing gas in the presence of the catalyst are also disclosed.

Abstract: A method for fabricating field emission cathode, a field emission cathode, and a field emission lighting source are provided. The method includes: forming a catalyst crystallite nucleus layer on the surface of cathode substrate by self-assembly of a noble metal catalyst, growing a composited nano carbon material on the cathode substrate by using a TCVD process, in which the composited nano carbon material includes coil carbon nano tubes and coil carbon nano fibers. The measured quantity of total coil carbon nano tubes and coil carbon nano fibers is higher than 40%. The field emission cathode is fabricated by the aforementioned method, and the field emission lighting source includes the aforementioned field emission cathode.

Abstract: A method of making a metal oxide nanoparticle comprising contacting an aqueous solution of a metal salt with an oxidant. The method is safe, environmentally benign, and uses readily available precursors. The size of the nanoparticles, which can be as small as 1 nm or smaller, can be controlled by selecting appropriate conditions. The method is compatible with biologically derived scaffolds, such as virus particles chosen to bind a desired material. The resulting nanoparticles can be porous and provide advantageous properties as a catalyst.

Abstract: A method of producing a catalyst material with nano-scale structure, the method comprising: introducing a starting powder into a nano-powder production reactor, the starting powder comprising a catalyst material; the nano-powder production reactor nano-sizing the starting powder, thereby producing a nano-powder from the starting powder, the nano-powder comprising a plurality of nano-particles, each nano-particle comprising the catalyst material; and forming a catalyst precursor material from the nano-powder, wherein the catalyst precursor material is a densified bulk porous structure comprising the catalyst material, the catalyst material having a nano-scale structure.

Abstract: A catalyst composition for converting ethanol to higher alcohols, such as butanol, is disclosed. The catalyst composition comprises at least one alkali metal, at least a second metal and a support. The second metal is selected from the group consisting of palladium, platinum, copper, nickel, and cobalt. The support is selected from the group consisting of Al2O3, ZrO2, MgO, TiO2, zeolite, ZnO, and a mixture thereof.

Abstract: The present invention relates to a catalyst for Fischer-Tropsch synthesis which has excellent heat transfer capability. This catalyst contains (1) central core particle or particles made of a heat transfer material (HTM) selected from the group consisting of a metal, a metal oxide, a ceramic, and a mixture thereof; and (2) outer particle layer which surrounds the central core particles and is attached to the surfaces of the central core particles by a binder material layer. The outer particle layer has a support and catalyst particles in a powder form containing metal particles disposed on the support. The catalyst having such a dual particle structure shows excellent heat transfer capability and, thus, exhibits high selectivity to a target hydrocarbon. Therefore, the catalyst of the present invention is useful in a fixed-bed reactor for Fischer-Tropsch synthesis for producing hydrocarbons from synthetic gas.

Abstract: Disclosed is an alloy of the formula: Fe3?xAl1+xMyTzTat wherein M represents at least one catalytic specie selected from the group consisting of Ru, Ir, Pd, Pt, Rh, Os, Re and Ag; T represents at least one element selected from the group consisting of Mo, Co, Cr, V, Cu, Zn, Nb, W, Zr, Y, Mn, Cd, Si, B, C, O, N, P, F, S, CI, Na and Ti; and Ta represents tantalum. Such an alloy can be used as an electrode material for the synthesis of sodium chlorate. It can also be used as a coating for protection against corrosion.

Abstract: One exemplary embodiment can be a slurry hydrocracking process. The process can include providing one or more hydrocarbon compounds having an initial boiling point temperature of at least about 340° C., and a slurry catalyst to a slurry hydrocracking zone. The slurry catalyst may have about 32-about 50%, by weight, iron; about 3-about 14%, by weight, aluminum; no more than about 10%, by weight, sodium; and about 2-about 10%, by weight, calcium. Typically, all catalytic component percentages are as metal and based on the weight of the dried slurry catalyst.

Abstract: An emission control catalyst composition comprising a supported bimetallic catalyst consisting of gold and a metal selected from the group consisting of platinum, rhodium, ruthenium, copper and nickel is disclosed. Also disclosed is a catalytic convertor comprising a substrate monolith coated with the emission control catalyst composition and a lean burn internal combustion engine exhaust gas emission treatment system comprising the catalytic convertor. A variety of processes for preparing the catalyst composition are claimed.

Abstract: A catalyst composition comprising a vanadate represented by the formula XVO4/S, wherein XVO4 stands for a Bi-, Sb-, Ga- and/or Al-vanadate optionally in mixture with one or more rare earth metal-vanadates, or in mixture with one or more transition metal-vanadates, or in mixture with one or more transition metal-vanadates and one or more rare earth metal-vanadates, and S is a support comprising TiO2, optionally in combination with a dopant and a process for the preparation of such catalyst compositions.

Abstract: A method of producing an alumina-supported cobalt catalyst for use in a Fischer-Tropsch synthesis reaction, which comprises: calcining an initial ?-alumina support material at a temperature to produce a modified alumina support material; impregnating the modified alumina support material with a source of cobalt; calcining the impregnated support material, activating the catalyst with a reducing gas, steam treating the activated catalyst, and activating the steam treated catalyst with a reducing gas.

Abstract: A method of producing stable ferrous nitrate solution by dissolving iron in nitric acid to form a ferrous nitrate solution and maintaining the solution at a first temperature for a first time period, whereby the Fe(II) content of the ferrous nitrate solution changes by less than about 2% over a second time period. A method of producing stable Fe(II)/Fe(III) nitrate solution comprising ferrous nitrate and ferric nitrate and having a desired ratio of ferrous iron to ferric iron, including obtaining a stable ferrous nitrate solution; dissolving iron in nitric acid to form a ferric nitrate solution; maintaining the ferric nitrate solution at a second temperature for a third time period; and combining amounts of stable ferrous nitrate solution and ferric nitrate solution to produce the stable Fe(II)/Fe(III) nitrate solution. A method of preparing an iron catalyst is also described.

Abstract: A structurally promoted, precipitated, Fischer-Tropsch catalyst that exhibits an RCAI-10 of 0-2.8 and/or produces less than 6 wt % fines after 5 hours ASTM Air Jet Attrition testing, due to formation via: preparing a nitrate solution by forming at least one metal slurry and combining the at least one metal slurry with a nitric acid solution; combining the nitrate solution with a basic solution to form a precipitate; structurally promoting the precipitate with at least one source of silicon to form a promoted mixture, wherein promoting comprises combining the precipitate with (a) silicic acid and one or more component selected from the group consisting of non-crystalline silicas, crystalline silicas, and sources of kaolin or (b) a component selected from the group consisting of non-crystalline silicas and sources of kaolin, in the absence of silicic acid; and spray drying the promoted mixture to produce catalyst having a desired particle size.

Abstract: The present invention relates to catalysts, to processes for making catalysts and to chemical processes employing such catalysts. The multifunctional catalysts are preferably used for converting acetic acid and ethyl acetate to ethanol. The catalyst is effective for providing an acetic acid conversion greater than 20% and an ethyl acetate conversion greater than 0%. The catalyst comprises a precious metal and one or more active metals on a modified support. The modified support includes a metal selected from the group consisting of tungsten, vanadium, and tantalum, provided that the modified support does not contain phosphorous.

Abstract: A method of forming a Fischer-Tropsch catalyst by providing at least one metal nitrate solution, combining each of the at least one metal nitrate solutions with a precipitating agent whereby at least one catalyst precipitate is formed, and incorporating a strong base during precipitation, subsequent precipitation, or both during and subsequent precipitation. Catalysts produced via the disclosed method are also provided.

Abstract: A porous oxide catalyst includes porous oxide, and an oxygen vacancy-inducing metal which induces an oxygen vacancy in a lattice structure of a porous metal oxide.

Abstract: A catalyst composition is provided comprising a homogeneous solid mixture having ordered directionally aligned tubular meso-channel pores having an average diameter in a range of about 1 nanometer to about 15 nanometers, wherein the homogeneous solid mixture is prepared from a gel formed in the presence of a solvent, modifier, an inorganic salt precursor of a catalytic metal, an inorganic precursor of a metal inorganic network, and a templating agent. The templating agent comprises an octylphenol ethoxylate having a structure [I]: wherein “n” is an integer having a value of about 8 to 20.

Abstract: Provided are a method of preparing an electrocatalyst for fuel cells in a core-shell structure, an electrocatalyst for fuel cells having a core-shell structure, and a fuel cell including the electrocatalyst for fuel cells. The method may be useful in forming a core and a shell layer without performing a subsequent process such as chemical treatment or heat treatment and forming a core support in which core particles having a nanosize diameter are homogeneously supported, followed by selectively forming shell layers on surfaces of the core particles in the support. Also, the electrocatalyst for fuel cells has a high catalyst-supporting amount and excellent catalyst activity and electrochemical property.

Abstract: The present invention relates to a novel sensor for detecting the early stages of catalyst coking in fuel reforming systems and methods for making and using the same. The sensor may be manufactured by inkjet printing a colloidal suspension of ceramic powders to create thin (about 20 ?m) catalytic and conductive elements of the sensor. The sensor may be used to determine the presence of coking conditions during processes at a level below the detection limit available using thermogravimetric analyzers (TGA) (<10 ?g), thereby reducing catalyst coking in systems.

Abstract: Disclosed is a process for the production of lower olefins by the conversion of a feed stream comprising carbon monoxide and hydrogen, and catalysts as used therein, such as a Fischer-Tropsch process. By virtue of the invention, lower olefins can be formed from synthesis gas, with high selectivity, and low production of methane. The catalysts used herein comprise an ?-alumina support, and a catalytically active component that comprises iron-containing particles dispersed onto the support in at least 1 wt. %. The majority of the iron-containing particles is in direct contact with the ?-alumina and is well-distributed thereon. Preferably, the iron-containing particles have an average particle size below 30 nm, and most preferably below 10 nm. The supported catalysts not only show a high selectivity, but also a high catalyst activity and chemical and mechanical stability.

Abstract: The present invention relates to a process for the hydrogenation, in particular the selective hydrogenation of unsaturated hydrocarbon compounds, such as the selective hydrogenation of acetylene to ethylene, using a hydrogenation catalyst comprising an ordered intermetallic compound, namely an ordered cobalt-aluminum or iron-aluminum intermetallic compound. According to another aspect, the present invention relates to a catalyst comprising a support and at least one specific ordered cobalt-aluminum and/or iron-aluminum intermetallic compound supported thereon, as well as to the use of specific ordered intermetallic cobalt-aluminum and iron-aluminum intermetallic compounds as catalysts. The ordered cobalt-aluminum and iron-aluminum intermetallic compounds proved to be highly selective and long-term stable catalysts, e.g. in the selective hydrogenation of acetylene to ethylene in a large excess of ethylene.

Abstract: A cermet catalyst material, including a spinel matrix defining a spinel grain and a plurality metal particles embedded in and on the surface of the spinel grain. When the spinel grain is in a first oxidizing atmosphere and at a temperature above about 800 degrees Celsius the metal particles are absorbed into the spinel matrix in the form of metal cations. When the grain is in an second, less oxidizing atmosphere and at a temperature below about 1100 degrees Celsius the metal cations emerge from the spinel matrix to yield a plurality of metal particles adhering to the spinel grain or residing in intragranular pores.

Abstract: The invention relates to a filtration structure, for filtering a gas coming from a diesel engine, which is laden with gaseous pollutants of the nitrogen oxide NOx type and with solid particles, of the particulate filter type, said filtration structure being characterized in that it includes a catalytic system comprising at least one noble metal or transition metal suitable for reducing the NOx and a support material, in which said support material comprises or is made of a zirconium oxide partially substituted with a trivalent cation M3+ or with a divalent cation M?2+, said zirconium oxide being in a reduced, oxygen-sub-stoichiometric, state.

Abstract: A method of producing a Fischer-Tropsch catalyst by preparing a nitrate solution, wherein preparing comprises forming at least one metal slurry and combining the at least one metal slurry with a nitric acid solution; combining the nitrate solution with a basic solution to form a precipitate; promoting the precipitate to form a promoted mixture, wherein promoting comprises combining the precipitate with (a) silicic acid and one or more selected from the group consisting of non-crystalline silicas, crystalline silicas, and sources of kaolin or (b) at least one selected from non-crystalline silicas and sources of kaolin, in the absence of silicic acid; and spray drying the promoted mixture to produce catalyst having a desired particle size. Catalyst produced by the disclosed method is also described.

Abstract: The present invention relates to a method for preparing iron-containing porous organic-inorganic hybrid materials where the organic compound ligand is bonded to a central metal and has a large surface area and pores of molecular size or nano size, by irradiating microwaves instead of heat treatments such as the conventional electric heating, etc. as the heat source of the hydrothermal or solvothermal synthesis reaction, after reacting a metal or metal salt and organic compound to form crystal nuclei by a predetermined pre-treatment operation in the presence of a solvent. In another aspect, a method of the present invention further comprises the step of purifying the obtained porous organic-inorganic hybrid materials by treating them with inorganic salt. In particular, a method of the present invention is characterized by not using a hydrofluoric acid.

Abstract: Described is a nitrogen oxide storage catalyst comprising: a substrate; a first washcoat layer provided on the substrate, the first washcoat layer comprising a nitrogen oxide storage material, a second washcoat layer provided on the first washcoat layer, the second washcoat layer comprising a hydrocarbon trap material, wherein the hydrocarbon trap material comprises substantially no element or compound in a state in which it is capable of catalyzing selective catalytic reduction, preferably wherein the hydrocarbon trap material comprises substantially no element or compound in a state in which it is capable of catalyzing a reaction wherein nitrogen oxide is reduced to N2, said catalyst further comprising a nitrogen oxide conversion material which is either comprised in the second washcoat layer and/or in a washcoat layer provided between the first washcoat layer and the second washcoat layer.

Abstract: This invention relates to the field of Fischer-Tropsch catalysis, in particular to activation of a Fischer-Tropsch catalyst. More particularly the invention relates to a method of activating an iron based Fischer-Tropsch catalyst which includes iron in a positive oxidation state by contacting in a reactor said iron based catalyst with a reducing gas selected from the group consisting of CO and a combination of H2 and CO; at a temperature of at least 245° C. and below 280° C.; at a reducing gas pressure of above 0.5 MPa and not more than 2.2 MPa; and at a GHSV of total gas fed to the reactor of at least 6000 ml(N)/g cat/h, thereby reducing the iron that is in a positive oxidation step in the catalyst.

Abstract: A method for providing a catalyst on a substrate is disclosed comprising providing a first washcoat comprising a soluble washcoat salt species, a polar organic solvent, and an insoluble particulate material, contacting the first washcoat with a substrate to form a coated substrate, and then contacting the coated substrate with a second washcoat comprising an oxide or an oxide-supported catalyst to physisorb, chemisorb, bond, or otherwise adhere the oxide or the oxide-supported catalyst to the coated substrate. Also disclosed is a catalyst on a substrate comprising: a substrate; an anchor layer comprising a soluble washcoat salt species, a polar organic solvent, and an insoluble particulate material; and a second layer comprises an oxide or an oxide-supported catalyst. The catalyst on a substrate can be in either green or fired form.

Abstract: An exhaust gas purifying catalyst (1) of the present invention includes anchor/promoter simultaneous enclosure particles (5) including catalyst units (13) which contain: noble metal particles (8); and anchor particles (9) as an anchor material of the noble metal particles (8) supporting the noble metal particles (8); promoter units (14) which are provided not in contact with the noble metal particles (8) and contain first promoter particles (11) having an oxygen storage and release capacity; and an enclosure material (12) which encloses both the catalyst units (13) and the promoter units (14), and separates the noble metal particles (8) and the anchor particles (9) in the catalyst units (13) from the first promoter particles (11) in the promoter units (14). The exhaust gas purifying catalyst (1) further includes second promoter particles (6) which have the oxygen storage and release capacity, and are not enclosed in the anchor/promoter simultaneous enclosure particles (5) by the enclosure material (12).

Abstract: A bulk metal oxide catalyst composition of the general formula (X)b(M)c(Z)d(O)e??(I) wherein X represents at least one non-noble Group VIII metal; M represents at least one non-noble Group VIb metal; Z represents one or more elements selected from aluminum, silicon, magnesium, titanium, zirconium, boron, and zinc; one of b and c is the integer 1; and d and e and the other of b and c each are a number greater than 0 such that the molar ratio of b:c is in the range of from 0.5:1 to 5:1, the molar ratio of d:c is in the range of from 0.2:1 to 50:1, and the molar ratio of e:c is in the range of from 3.7:1 to 108:1; is prepared by controlled (co)precipitation of component metal compounds, refractory oxide material, and alkali compound in protic liquid. Resulting compositions find use in hydrotreatment processes involving particularly hydrodesulphurization and hydrodenitrification.

Abstract: A mesoporous oxide-catalyst complex including: a mesoporous metal oxide; and a catalyst metal supported on the mesoporous metal oxide, wherein the catalyst on the mesoporous metal oxide has a degree of dispersion of about 30 to about 90 percent.

Abstract: An exhaust gas purifying catalyst is constituted by: noble metal particles (1); first compounds (2) which support the noble metal particles (1); second compounds (3) different in type from the first compounds (2); and oxides (4) which surround the noble metal particles (1), the first compounds (2) and the second compounds (3). A median diameter of the first compounds (2) and a median diameter of the second compounds (3) satisfy a relationship of a following inequality: median diameter of first compounds<median diameter of second compounds.

Abstract: A series of binary and ternary Pt-alloys, that promote the important reactions for catalysis at an alloy surface; oxygen reduction, hydrogen oxidation, and hydrogen and oxygen evolution. The first two of these reactions are essential when applying the alloy for use in a PEMFC.

Abstract: According to various embodiments, a catalyst composition includes a catalytic metal secured to a porous substrate. The substrate has pores that are templated. The substrate is a product of adding a substrate precursor to a water-in-oil microemulsion including a catalytic metal salt, a solvent, a templating agent, and water.

Abstract: There is provided a method for production of a conjugated diene from a monoolefin having four or more carbon atoms by a fluidized bed reaction. The method for production of a conjugated diolefin includes bringing a catalyst in which an oxide is supported on a carrier into contact with a monoolefin having four or more carbon atoms in a fluidized bed reactor in which the catalyst and oxygen are present, wherein the method satisfies the following (1) to (3): (1) the catalyst contains Mo, Bi, and Fe; (2) a reaction temperature is in the range of 300 to 420° C.; and (3) an oxygen concentration in a reactor outlet gas is in the range of 0.05 to 3.0% by volume.

Abstract: The present invention relates to a catalyst-containing nanofiber composition, comprising a ceramic nanofiber having a plurality of metal catalysts wherein the metal catalysts exist as dispersed particles partially embedded in the nanofiber and cover from about 1% to about 90% of the surface area of the ceramic nanofiber.

Abstract: A method of producing a catalyst material with nano-scale structure, the method comprising: introducing a starting powder into a nano-powder production reactor, the starting powder comprising a catalyst material; the nano-powder production reactor nano-sizing the starting powder, thereby producing a nano-powder from the starting powder, the nano-powder comprising a plurality of nano-particles, each nano-particle comprising the catalyst material; and forming a catalyst precursor material from the nano-powder, wherein the catalyst precursor material is a densified bulk porous structure comprising the catalyst material, the catalyst material having a nano-scale structure.

Abstract: Provided are improved regenerable SOx trap formulations for on-board vehicle applications. The regenerable sulfur trap formulations reduce the rate of sulfur poisoning of a downstream nitrogen storage reduction (NSR) catalyst trap in exhaust gas cleaning systems for combustion engines by adsorbing SOx as metal sulfate under lean exhaust conditions and desorbing the accumulated SOx under rich exhaust conditions. The regenerable sulfur oxides trap catalyst compositions include a metal (M) oxide, wherein M is selected from Cu, Fe, Mn, Ag, Co and combinations thereof and a metal (M)-La—Zr oxide, wherein M is selected from Cu, Fe, Mn, Ag, Co and combinations thereof. In addition, provided are improved exhaust gas cleaning systems and methods for treating exhaust gas from a combustion source that include a hydrogen generation system, a regenerable sulfur oxides trap, and a regenerable nitrogen storage reduction (NSR) catalyst trap.

Abstract: A process is described for producing a powder batch comprises a plurality of particles, wherein the particles include (a) a first catalytically active component comprising at least one transition metal or a compound thereof; (b) a second component different from said first component and capable of removing oxygen from, or releasing oxygen to, an exhaust gas stream; and (c) a third component different from said first and second components and comprising a refractory support. The process comprises providing a precursor medium comprising a liquid vehicle and a precursor to al least one of said components (a) to (c) and heating droplets of said precursor medium carried in a gas stream to remove at least part of the liquid vehicle and chemically convert said precursor to said at least one component.

Abstract: A nanocomposite particle, its use as a catalyst, and a method of making it are disclosed. The nanocomposite particle comprises titanium dioxide nanoparticles, metal oxide nanoparticles, and a surface stabilizer. The metal oxide nanoparticles are formed hydrothermally in the presence of the titanium dioxide nanoparticles. The nanocomposite particle is an effective catalyst support, particularly for DeNOx catalyst applications.

Abstract: An exhaust gas purifying catalyst (1) according to the present invention includes noble metal particles (6), a first compound (7) supporting the noble metal particles (6), and a second compound (9) disposed not in contact with the noble metal particles (6) and having an oxygen storage capacity. An average distance between the first compound (7) and the second compound (9) is between 5 nm and 300 nm.

Abstract: Methods and systems for contacting of a crude feed with one or more catalysts to produce a total product that includes a crude product are described. The crude product is a liquid mixture at 25° C. and 0.101 MPa. The crude product has an MCR content of at most 90% of the MCR content of the crude feed. One or more other properties of the crude product may be changed by at least 10% relative to the respective properties of the crude feed.

Abstract: A composite material includes an aggregate which contains a first metal particle constituting a core and second metal oxide particulates surrounding the first metal particle and having an average primary particle diameter ranging from 1 to 100 nm.

Abstract: An exhaust gas purifying catalyst includes a monolithic substrate (2), and a transition metal oxide layer (3) formed in the monolithic substrate (2). The transition metal oxide layer (3) contains transition metal oxide powder including: transition metal oxide particles (10); a first compound (20) on which the transition metal oxide particles (10) are supported; and a second compound (30) that surrounds a single body or an aggregate of the transition metal oxide particles (10) and the first compound (20).

Abstract: A process for producing a catalyst, the process comprising the steps of: impregnating a first metal from a first metal precursor on a support to form a first impregnated support; calcining the first impregnated support; impregnating a second metal from a second metal precursor on the first impregnated support to form a second impregnated support; calcining the second impregnated support to form the catalyst, wherein the catalyst has a total metal loading of at least 2 wt. % based on the total weight of the catalyst. A method for hydrogenating alkanoic acids in the presence of the catalyst is also disclosed.

Abstract: The present invention is directed to a granulate having photocatalytic activity, comprising particles of an inorganic particulate material coated with a photocatalytically active compound for introducing photocatalytic activity into or on building materials. The invention is further related to the manufacture of such a granulate and its use into or on building materials such as cement, concrete, gypsum and/or limestone and water-based coatings or paints for reducing an accumulation and growth of microorganisms and environmental polluting substances on these materials and thus reducing the tendency of fouling, while the brilliance of the color is maintained and the quality of the air is improved.

Abstract: A method of preparing a catalyst support is described comprising washing a precipitated metal oxide material with water and/or an aqueous solution of acid and/or base such that contaminant levels in said precipitated metal oxide are reduced. The method may be applied to precipitated alumina materials to reduce contaminants selected from sulphur, chlorine, Group 1A and Group 2A metals. The catalyst supports may be used to prepare catalysts for the Fischer-Tropsch synthesis of hydrocarbons.

Abstract: A catalyst composition comprising a vanadate represented by the formula XVO4/S, wherein XVO4 stands for a Bi-, Sb-, Ga- and/or Al-vanadate optionally in mixture with one or more rare earth metal-vanadates, or in mixture with one or more transition metal-vanadates, or in mixture with one or more transition metal-vanadates and one or more rare earth met-al-vanadates, and S is a support comprising TiO2, optionally in combination with a dopant and a process for the preparation of such catalyst composi-tions.