HYDROGEN PRODUCING CATALYST, EXHAUST GAS CLEANING CATALYST AND EXHAUST GAS CLEANING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a hydrogen producing catalyst suppressed not only in the particle growth of a noble metal but also in the poisoning due to sulfur. SOLUTION: A hydrogen producing catalyst consists of a carrier, wherein zirconia and yttria are contained in an atomic ratio of Zr:Y=80:20-20:80 and at least a part of zirconia and yttria forms a solid solution, and a noble metal supported on the carrier. Since Zr and Y are alloyed with the noble metal to form a solid solution and the recrystallization temperature of the noble metal becomes high, particle growth is considered to be suppressed and the particle growth of the noble metal is suppressed. The sulfur oxide adsorbed on the solid solution of zirconia and yttria forms composite sulfate of a kind and this composite sulfate is easily decomposed because unstable as compared with independent sulfate of zirconia or yttria.