Abstract: The present invention relates to a catalyst for purifying exhaust and waste gases which is capable of simultaneously removing nitrogen oxide, carbon monoxide and hydrocarbons from the exhaust gases, comprising supporting phosphorus, barium, rhodium and at least one member selected from the group consisting of palladium and platinum, and optionally nickel on a carrier, and a method for preparation thereof.

Abstract: A catalyst for purifying exhaust and waste gases comprisingA. a support substrate comprising 2 to 100% by weight of an oxide complex of titanium and phosphorus containing titanium and phosphrus in such a proportion that the molar ratio of TiO.sub.2 to P.sub.2 O.sub.5 is from 5.0 to 0.5 and 98 to 0% by weight of aluminum oxide, andB. supported on said substrate as a catalytic substance, 2 to 300 parts by weight, calculated as metal oxide per 100 parts by weight of the support substrate (A), of at least one heavy metal selected from the group consisting of Ni, Cu, Cr, Fe, Co, Mn, Bi, V, W, Mo, Sn, Zn, Zr, Pb, Sb, Ti, Ta, Cd and Nb, or 0.01 to 1.0 part by weight, calculated as metal per 100 parts by weight of the support substrate (A), of at least one noble metal selected from the group consisting of Pt, Pd, Rh, Ir, Os and Ru.

Abstract: A catalyst for removing nitrogen oxides, carbon monoxide, and hydrocarbons in exhaust gases, said catalyst being prepared by supporting copper and nickel on a carrier and then further supporting at least two components selected from the group consisting of iridium, rhodium and ruthenium, the atomic weight ratio of copper to nickel being 0.2 to 5, the atomic weight ratio of the sum of copper and nickel to the sum of at least two components selected from the group consisting of iridium, rhodium and ruthenium being 10 to 100,000, and the total weight of copper and nickel being 10 to 200 g per liter of the catalyst.