Abstract: Solid supported catalysts for catalytic reduction of nitrogen oxide in waste gases utilizing ammonia as the reducing agent, the catalyst comprising at least one metallic oxide, sulfate or phosphate of a first transition metal supported on an alumina or silica-alumina carrier; the carrier containing from 0.03 to 20% by weight sulfur, based on the weight of the carrier, calculated as a sulfate or sulfite radical.

Abstract: A process for the removal of nitrogen oxides from a waste gas containing said nitrogen oxides in conjunction with sulfur oxides is disclosed, which process comprises allowing said waste gas to come into contact with ammonia as the reducing agent at temperature in the range of from 250.degree. to 550.degree. C in the presence of a catalyst wherein an active component containing iron or copper as the active metal is supported on a silica-alumina type carrier containing not less than 60% by weight of silica and the pore volume occupied by the pores measuring 150 A or over in diameter exceeds 0.15 cc/g, for thereby causing selective catalytic reduction of said nitrogen oxides.