Abstract: The present invention relates to a methane combustion catalyst including platinum and iridium supported on a tin oxide carrier for combusting methane in a combustion exhaust gas containing sulfur oxide. In this methane combustion catalyst, in line analysis by electron probe microanalysis performed on an arbitrary cross-section thereof from a deepest catalyst portion toward a catalyst surface, a first region where all of platinum, iridium and tin are detected and a second region where tin is essentially detected but platinum is not detected are both observable. In a specific form, the catalyst includes a base catalyst layer where platinum and iridium are supported on a tin oxide carrier, and an overcoat layer including tin oxide formed on the base catalyst layer. The methane combustion catalyst of the present invention is excellent in initial activity, and is improved in durability.

Abstract: The present invention relates to a methane combustion catalyst including platinum and iridium supported on a tin oxide carrier for combusting methane in a combustion exhaust gas containing sulfur oxide. In the methane combustion catalyst, a ratio RTO of platinum oxides to metal platinum is 8.00 or more, wherein the ratio RTO is based on existence percentages of the metal platinum (Pt) and the platinum oxides (PtO and PtO2) obtained from a platinum 4f spectrum analyzed and measured by X-ray photoelectron spectroscopy (XPS) and calculated in accordance with the following expression. In the following expression, RPt is an existence percentage of the metal platinum (Pt), RPto is an existence percentage of PtO, and RPto2 is an existence percentage of PtO2.

Abstract: The present invention provides a catalyst for combustion treatment of suspended particulate matter in diesel exhaust gases, and a combustion catalyst for treating diesel exhaust gases in which a precious metal or an oxide thereof as the catalytic component is loaded on a carrier composed of oxide ceramic particles comprising ceria-zirconia or ceria-praseodymium oxide. In the present invention, depending on the carried precious metal, the carrier is preferably composed of oxide ceramic particles further comprising yttria or lanthanum oxide. The present invention provides a sufficient activity to combust suspended particulate matter in exhaust gases, and can cause combustion at a low temperature of about 300° C. It operates stably for a long period, and can burn suspended particulate matter, especially carbon microparticles.

Abstract: The present invention relates to an exhaust gas cleaning catalyst, and aiming at providing a catalyst which has a higher catalytic activity than that of conventional catalysts and, in particular, a strong ability to oxidize nitrogen monoxide. The present invention relates to an exhaust gas cleaning catalyst whose catalytic component is supported on a carrier, characterized in that the catalytic component is platinum colloid which has an average particle size of 80 nm to 120 nm, a particle size D20, a 20% cumulative particle size distribution from smaller particle size side, of 50 nm or more, and a particle size D90, a 90% cumulative particle size distribution from smaller particle size side, of 200 nm or less. The exhaust gas cleaning catalyst of the present invention has a high catalytic activity for cleaning exhaust gases and, in particular, a strong ability to oxidize nitrogen monoxide.

Abstract: The present invention relates to an exhaust gas cleaning catalyst, and aiming at providing a catalyst which has a higher catalytic activity than that of conventional catalysts and, in particular, a strong ability to oxidize nitrogen monoxide. The present invention relates to an exhaust gas cleaning catalyst whose catalytic component is supported on a carrier, characterized in that the catalytic component is platinum colloid which has an average particle size of 80 nm to 120 nm, a particle size D20, a 20% cumulative particle size distribution from smaller particle size side, of 50 nm or more, and a particle size D90, a 90% cumulative particle size distribution from smaller particle size side, of 200 nm or less. The exhaust gas cleaning catalyst of the present invention has a high catalytic activity for cleaning exhaust gases and, in particular, a strong ability to oxidize nitrogen monoxide.

Abstract: The present invention provides a catalyst for combustion treatment of suspended particulate matter in diesel exhaust gases, and a combustion catalyst for treating diesel exhaust gases in which a precious metal or an oxide thereof as the catalytic component is loaded on a carrier composed of oxide ceramic particles comprising ceria-zirconia or ceria-praseodymium oxide. In the present invention, depending on the carried precious metal, the carrier is preferably composed of oxide ceramic particles further comprising yttria or lanthanum oxide. The present invention provides a sufficient activity to combust suspended particulate matter in exhaust gases, and can cause combustion at a low temperature of about 300° C. It operates stably for a long period, and can burn suspended particulate matter, especially carbon microparticles.