A process for producing polymer-supported metal nanoparticles involves confinement of metal nanoparticles in polymeric nanotubes or nanosheets in an aqueous environment using hydrophobic reactants. Metal nanoparticles supported in the polymeric nanotubes or nanosheets are substantially monodisperse and have an average particle size of 4 nm or less. The polymer-supported metal nanoparticles are useful in fuel cells, sensors, bioanalysis, biological labeling or semi-conductors, especially as catalysts.

A process for producing polymer-supported metal nanoparticles involves confinement of metal nanoparticles in polymeric nanotubes or nanosheets in an aqueous environment using hydrophobic reactants. Metal nanoparticles supported in the polymeric nanotubes or nanosheets are substantially monodisperse and have an average particle size of 4 nm or less. The polymer-supported metal nanoparticles are useful in fuel cells, sensors, bioanalysis, biological labeling or semi-conductors, especially as catalysts.

The exhaust gas-purifying catalyst of the invention contains oxide particles having interdispersed therein A crystallites that are loaded with a noble metal and B crystallites that are not loaded with a noble metal. The A crystallites loaded with a noble metal are composed of an oxide containing at least one of zirconium (Zr) and cerium (Ce). The B crystallites not loaded with a noble metal are composed of a cerium (Ce)-containing oxide which has a higher Ce content (mol %) than the oxide making up the A crystallites. The oxide particles have a specific surface area after 5 hours of heat treatment at 1,150° C. in open air of 30 m.sup.2/g or more.

The exhaust gas-purifying catalyst of the invention contains oxide particles having interdispersed therein A crystallites that are loaded with a noble metal and B crystallites that are not loaded with a noble metal. The A crystallites loaded with a noble metal are composed of an oxide containing at least one of zirconium (Zr) and cerium (Ce). The B crystallites not loaded with a noble metal are composed of a cerium (Ce)-containing oxide which has a higher Ce content (mol %) than the oxide making up the A crystallites. The oxide particles have a specific surface area after 5 hours of heat treatment at 1,150° C. in open air of 30 m.sup.2/g or more.

A method for producing ketones includes a) providing a feedstock of biological origin having fatty acids and/or fatty acid derivatives having an average chain length of 24 C-atoms or less; b) subjecting the feedstock to a catalytic ketonization reaction in the presence of aK.sub.2O/TiO.sub.2-catalyst; and c) obtaining from the ketonization reaction a product stream having ketones, which ketones have a longer average hydrocarbon chain length than the average hydrocarbon chain length in the feedstock, wherein step b) is carried out directly on the feedstock and in the presence of the K.sub.2O/TiO.sub.2-catalyst as the sole catalyst applied in the ketonization reaction.

A method of carrying out the dehydrogenation of lower alkanes in a fixed-bed reactor containing a catalyst bed, the catalyst bed comprising (i) catalyst particles supporting a catalyst effective to promote said dehydrogenation and (ii) engineered inert diluent particles, where the method comprises passing the lower alkane in gaseous form through the catalyst bed, wherein the engineered inert diluent particles have a cross-sectional shape having two opposing convex edges joined by and intersecting two opposing concave edges, and a plurality of holes between said edges penetrating through the particle.

A nitrous oxide (N.sub.2O) removal catalyst composite is provided, comprising a N.sub.2O removal catalytic material on a substrate, the catalytic material comprising a rhodium (Rh) component supported on a ceria-based support, wherein the catalyst composite has a H.sub.2-consumption peak of about 100° C. or less as measured by hydrogen temperature-programmed reduction (H.sub.2-TPR). Methods of making and using the same are also provided.

A nitrous oxide (N.sub.2O) removal catalyst composite is provided, comprising a N.sub.2O removal catalytic material on a substrate, the catalytic material comprising a rhodium (Rh) component supported on a ceria-based support, wherein the catalyst composite has a H.sub.2-consumption peak of about 100° C. or less as measured by hydrogen temperature-programmed reduction (H.sub.2-TPR). Methods of making and using the same are also provided.

Provided are an LNT layered catalyst for a lean burn gasoline engine having an enhanced NOx storage rate and capable of developing a higher NOx purification rate, and an exhaust gas purification apparatus using the same, the LNT layered catalyst including a substrate, a first catalyst layer including ceria-alumina particles carrying Pt, Pd, and BaO, and a second catalyst layer including ceria-alumina particles carrying Pt and Rh, in which a content of Pt in the first catalyst layer is 0.45 to 0.85 mass %; among Pt included in the first catalyst layer, a content proportion in a first depth region is 88 to 90 mass %, and a content proportion in a second depth region is 10 to 12 mass %; a content of Ba in the first catalyst layer is 4 to 11 mass %; and the second catalyst layer is substantially free from Ba.

Provided are an LNT layered catalyst for a lean burn gasoline engine having an enhanced NOx storage rate and capable of developing a higher NOx purification rate, and an exhaust gas purification apparatus using the same, the LNT layered catalyst including a substrate, a first catalyst layer including ceria-alumina particles carrying Pt, Pd, and BaO, and a second catalyst layer including ceria-alumina particles carrying Pt and Rh, in which a content of Pt in the first catalyst layer is 0.45 to 0.85 mass %; among Pt included in the first catalyst layer, a content proportion in a first depth region is 88 to 90 mass %, and a content proportion in a second depth region is 10 to 12 mass %; a content of Ba in the first catalyst layer is 4 to 11 mass %; and the second catalyst layer is substantially free from Ba.