A multicomponent photocatalyst includes a reactive component optically, electronically, or thermally coupled to a plasmonic material. A method of performing a catalytic reaction includes loading a multicomponent photocatalyst including a reactive component optically, electronically, or thermally coupled to a plasmonic material into a reaction chamber; introducing molecular reactants into the reaction chamber; and illuminating the reaction chamber with a light source.

The present invention discloses a rare-earth-manganese/cerium-zirconium-based composite compound, a method for preparing the same, and a use thereof. The composite compound is of a core-shell structure with a general formula expressed as: A RE.sub.cB.sub.aO.sub.b-(1-A)Ce.sub.xZr.sub.(1-x-y)M.sub.yO.sub.2-z, wherein 0.1?A?0.3, preferably 0.1?A?0.2; a shell layer has a main component of rare-earth manganese oxide with a general formula of RE.sub.cMn.sub.aO.sub.b, wherein RE is a rare-earth element or a combination of more than one rare-earth elements, and B is Mn or a combination of Mn and a transition metal element, 1?a?8, 2?b?18, and 0.25?c?4; and a core has a main component of cerium-zirconium composite oxide with a general formula of Ce.sub.xZr.sub.(1-x-y)M.sub.yO.sub.2-z, wherein M is one or more non-cerium rare-earth elements, 0.1?x?0.9, 0?y?0.3, and 0.01?z?0.3. The composite compound enhances an oxygen storage capacity of a cerium-zirconium material through an interface effect, thereby increasing a conversion rate of a nitrogen oxide.

A process for producing a catalyst, comprising the steps of modifying a carrier by a first impregnation with at least one alkaline earth metal in a first metal precursor solution, the first metal precursor being decomposed to form at least one metal oxide or metal hydroxide, thereby obtaining a modified carrier. A second impregnation is carried out by incipient wetness by a second precursor solution comprising at least one metal Me in a second solution. Finally, the second precursor is decomposed, thereby obtaining a catalyst body having an enrichment of the at least one metal Me in the outer shell of the catalyst body, the metal being present in a concentration having either as an egg-shell profile or a hammock profile.

A method for making a supported tantalum oxide catalyst precursor or catalyst with controlled Ta distribution and the resulting supported Ta catalyst. In an embodiment, the method comprises selecting a Ta-precursor with appropriate reactivity with the surface hydroxyls of the solid oxide support material to give a desired Ta distribution in the catalyst precursor or catalyst. In an embodiment the method comprises controlling the number of surface hydroxyls available on the support material to react with the Ta-precursor by thermal methods, such as calcination, to achieve the desired Ta distribution.

A process for preparing a catalyst material, includes the steps of: (a) providing a support material having surface hydroxyl (OH) groups, wherein the support material is ceria (CeO.sub.2), zirconia (ZrO.sub.2) or a combination of thereof; (b) reacting the support material having surface hydroxyl (OH) groups of step (a) with a precursor containing two transition metal atoms, each chosen independently from the group consisting of: W, Mo, Cr, Ta, Nb, V, Mn; (c) calcining the product obtained in step (b) in order to provide a catalyst material showing dual site surface species containing pairs of transition metal atoms derived from the precursor that are present in oxide form on the support material. Additionally, a catalyst material is obtained by the process set out above, and the catalyst material is used as an ammonia selective catalytic reduction (NH.sub.3-SCR) catalyst for nitrogen oxides (NOx) reduction.

Catalyst comprising a nickel-based active phase and an alumina support, characterized in that: the nickel is distributed both on a crust at the periphery of the support, and in the core of the support, the thickness of said crust being between 2% and 15% of the diameter of the catalyst; the nickel density ratio between the crust and the core is strictly greater than 3; said crust comprises between 40% and 80% by weight of nickel element relative to the total weight of nickel contained in the catalyst; the size of the nickel particles in the catalyst is less than 7 nm.

Nickel and copper catalyst, and an alumina support: nickel distributed both in the core of and on a crust at the periphery of the support, crust thickness being 2% to 15% of catalyst diameter; nickel density ratio between the crust and the core greater than 3; crust contains more than 25% by weight of nickel element relative to total weight of nickel in the catalyst; mole ratio between nickel and copper is 0.5 to 5, at least one portion of nickel and copper is a nickel-copper alloy; nickel content in the nickel-copper alloy is 0.5% to 15% by weight of nickel element relative to total weight of the catalyst; size of the nickel particles in the catalyst is less than 7 nm.

A method is described for preparing a catalyst comprising the steps of (i) preparing a calcined shaped calcium aluminate catalyst support, (ii) treating the calcined shaped calcium aluminate support with water, and then drying the support, (iii) impregnating the dried support with a solution containing one or more metal compounds and drying the impregnated support, (iv) calcining the dried impregnated support, to form metal oxide on the surface of the support and (v) optionally repeating steps (ii), (iii) and (iv) on the metal oxide coated support. The method provides an eggshell catalyst in which the metal oxide is concentrated in an outer layer on the support.

A method is described for preparing a catalyst comprising the steps of (i) preparing a calcined shaped calcium aluminate catalyst support, (ii) treating the calcined shaped calcium aluminate support with water, and then drying the support, (iii) impregnating the dried support with a solution containing one or more metal compounds and drying the impregnated support, (iv) calcining the dried impregnated support, to form metal oxide on the surface of the support and (v) optionally repeating steps (ii), (iii) and (iv) on the metal oxide coated support. The method provides an eggshell catalyst in which the metal oxide is concentrated in an outer layer on the support.

A method is described for preparing a catalyst including the steps of: (i) impregnating a calcined support comprising a metal aluminate with a solution of nickel acetate at a temperature 40 C. and drying the impregnated support, (ii) calcining the dried impregnated support, to form nickel oxide on the surface of the support and (iii) optionally repeating steps (i) and (ii) on the nickel oxide coated support. The method provides an eggshell catalyst in which the metal oxide is concentrated in an outer layer on the support.