The present invention relates to systems and methods for catalytic removal of oxidized contaminants (for example, nitrite, chromate, chlorate, trichloroethene, CFC-11, 4-nonylphenol, RDX, and perfluorooctanoate) from water and wastewater. In some aspects, the catalytic method of removing oxidized contaminants comprises using precious metal nanoparticles as catalysts to reduce the oxidized contaminants.

The present invention relates to systems and methods for catalytic removal of oxidized contaminants (for example, nitrite, chromate, chlorate, trichloroethene, CFC-11, 4-nonylphenol, RDX, and perfluorooctanoate) from water and wastewater. In some aspects, the catalytic method of removing oxidized contaminants comprises using precious metal nanoparticles as catalysts to reduce the oxidized contaminants.

There is provided a catalyst composition including a hydrogen oxidation catalyst and an oxygen reduction catalyst and a process for applying the catalyst composition to a substrate. Heat exchange reactors including the catalyst composition and methods for heating a heat exchange medium are also provided. Catalytic combustors including a catalytic surface including the catalyst composition are further provided. The catalyst is adapted for low temperature activation of a hydrogen combustion reaction.

There is provided a catalyst composition including a hydrogen oxidation catalyst and an oxygen reduction catalyst and a process for applying the catalyst composition to a substrate. Heat exchange reactors including the catalyst composition and methods for heating a heat exchange medium are also provided. Catalytic combustors including a catalytic surface including the catalyst composition are further provided. The catalyst is adapted for low temperature activation of a hydrogen combustion reaction.

The problem to be solved by the present invention is to provide an oxygen storage and release material comprising a ceria-zirconia-based complex oxide improved in ability to remove HC and NOx and a three-way catalyst able to reduce an amount of NOx emission. Further, to solve this problem, an oxygen storage and release material comprising a ceria-zirconia-based complex oxide containing Gd.sub.2O.sub.3 in 0.1 mol % or more and less than 20 mol % and having an ion conductivity of 2×10.sup.−5 S/cm or more at 400° C. is provided. Further, in addition to the above, an oxygen storage and release material having a molar ratio of cerium and zirconium of 0.2 or more and 0.6 or less by cerium/(cerium+zirconium) and an speed of oxygen storage and release “Δt.sub.50” of 20.0 seconds or more or amount of oxygen storage and release of 300 μmol-O.sub.2/g or more etc. was obtained. Further, by applying the oxygen storage and release material to the catalyst, it is possible to assist the purification of exhaust gas as it changes every instant in accordance with the driving conditions and possible to obtain a catalyst with a higher ability to remove harmful components of catalytic precious metals than before. In particular, it is possible to obtain an automotive exhaust gas purification system excellent in ability to remove CO, NOx, and HC.

The problem to be solved by the present invention is to provide an oxygen storage and release material comprising a ceria-zirconia-based complex oxide improved in ability to remove HC and NOx and a three-way catalyst able to reduce an amount of NOx emission. Further, to solve this problem, an oxygen storage and release material comprising a ceria-zirconia-based complex oxide containing Gd.sub.2O.sub.3 in 0.1 mol % or more and less than 20 mol % and having an ion conductivity of 2×10.sup.−5 S/cm or more at 400° C. is provided. Further, in addition to the above, an oxygen storage and release material having a molar ratio of cerium and zirconium of 0.2 or more and 0.6 or less by cerium/(cerium+zirconium) and an speed of oxygen storage and release “Δt.sub.50” of 20.0 seconds or more or amount of oxygen storage and release of 300 μmol-O.sub.2/g or more etc. was obtained. Further, by applying the oxygen storage and release material to the catalyst, it is possible to assist the purification of exhaust gas as it changes every instant in accordance with the driving conditions and possible to obtain a catalyst with a higher ability to remove harmful components of catalytic precious metals than before. In particular, it is possible to obtain an automotive exhaust gas purification system excellent in ability to remove CO, NOx, and HC.

Provided are a method for producing a fluoroethane, which is the desired product, with high selectivity; and a method for producing a fluoroolefin. The production method according to the present disclosure comprises obtaining a product comprising a fluoroethane represented by CX.sup.1X.sup.2FCX.sup.3X.sup.4X.sup.5 (wherein X.sup.1, X.sup.2, X.sup.3, X.sup.4, and X.sup.5 are the same or different and each represents a hydrogen atom, a fluorine atom, or a chlorine atom; and at least one of X.sup.1, X.sup.2, X.sup.3, X.sup.4, and X.sup.5 represents a hydrogen atom) from a fluoroethylene by a reaction in the presence of at least one catalyst in at least one reactor. The reaction is performed by introducing a starting material gas comprising the fluoroethylene into the reactor, and the water content in the starting material gas is 150 ppm by mass or less based on the total mass of the starting material gas.

Provided are a method for producing a fluoroethane, which is the desired product, with high selectivity; and a method for producing a fluoroolefin. The production method according to the present disclosure comprises obtaining a product comprising a fluoroethane represented by CX.sup.1X.sup.2FCX.sup.3X.sup.4X.sup.5 (wherein X.sup.1, X.sup.2, X.sup.3, X.sup.4, and X.sup.5 are the same or different and each represents a hydrogen atom, a fluorine atom, or a chlorine atom; and at least one of X.sup.1, X.sup.2, X.sup.3, X.sup.4, and X.sup.5 represents a hydrogen atom) from a fluoroethylene by a reaction in the presence of at least one catalyst in at least one reactor. The reaction is performed by introducing a starting material gas comprising the fluoroethylene into the reactor, and the water content in the starting material gas is 150 ppm by mass or less based on the total mass of the starting material gas.

A hydrogenation process is disclosed. The process involves reacting a fluoroolefin with H.sub.2 in a reaction zone in the presence of a palladium catalyst to produce a hydrofluoroalkane product, wherein the palladium catalyst comprises palladium supported on a carrier wherein the palladium concentration is from about 0.001 wt % to about 0.2 wt % based on the total weight of the palladium and the carrier. Also disclosed is a palladium catalyst composition consisting essentially of palladium supported on α-Al.sub.2O.sub.3 wherein the palladium concentration is from about 0.001 wt % to about 0.2 wt % based on the total weight of the palladium and the α-Al.sub.2O.sub.3. Also disclosed is a hydrogenation process comprising (a) passing a mixture comprising fluoroolefin and H.sub.2 through a bed of palladium catalyst in a reaction zone wherein the palladium catalyst comprises palladium supported on a carrier; and (b) producing a hydrofluoroalkane product; characterized by: the palladium catalyst in the front of the bed having lower palladium concentration than the palladium catalyst in the back of the bed.

A hydrogenation process is disclosed. The process involves reacting a fluoroolefin with H.sub.2 in a reaction zone in the presence of a palladium catalyst to produce a hydrofluoroalkane product, wherein the palladium catalyst comprises palladium supported on a carrier wherein the palladium concentration is from about 0.001 wt % to about 0.2 wt % based on the total weight of the palladium and the carrier. Also disclosed is a palladium catalyst composition consisting essentially of palladium supported on α-Al.sub.2O.sub.3 wherein the palladium concentration is from about 0.001 wt % to about 0.2 wt % based on the total weight of the palladium and the α-Al.sub.2O.sub.3. Also disclosed is a hydrogenation process comprising (a) passing a mixture comprising fluoroolefin and H.sub.2 through a bed of palladium catalyst in a reaction zone wherein the palladium catalyst comprises palladium supported on a carrier; and (b) producing a hydrofluoroalkane product; characterized by: the palladium catalyst in the front of the bed having lower palladium concentration than the palladium catalyst in the back of the bed.