Methane combustion catalyst and method for producing same, and method for purifying combustion exhaust gas

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.