Catalytic properties of novel La–Sr–Cu–O–S perovskites for automotive C 3H 6/CO oxidation in the presence of SO x

Abstract

A La–Sr–Cu–O–S system with K 2NiF 4 perovskite-type structure has been studied as a novel SO x -resistant combustion catalyst. The XRD result implied that sulfur is incorporated into the structure as non-sulfate-type cations. An introduction of sulfur with highly positive valence (S 6+ or S 4+) into the lattice requires the charge compensation by decreasing the oxidation number of Cu. This is accompanied by the creation of more reducible Cu species, which would achieve the light-off of catalytic C 3H 6 oxidation at lower temperatures. More important feature of sulfur-containing compounds is that the catalytic C 3H 6 oxidation was significantly accelerated by addition of SO 2 to the gas feed. The catalytic performance for the oxidation of C 3H 6 and CO and the reduction of NO was finally evaluated in a simulated automotive exhaust in the presence of SO 2.