Catalyst

Patent Pending PROBLEM TO BE SOLVED: To provide a high performance catalyst using composite oxide for a steam reforming reaction of methanol, and a method for the preparation thereof. ; SOLUTION: A composite oxide catalyst for a steam reforming reaction of methanol which is characterized in that it is prepared by a reduction treatment of a spinel type compound comprising a ternary or higher component composite oxide having a composition represented by A<SB>x</SB>B<SB>y</SB>O<SB>z</SB>, wherein A-O bonding force is <B-O bonding force, and by forming nanoparticles of A metal inside pores of porous B-O oxide.