Composite oxide for hydrocarbon reforming catalyst, process for producing the same, and process for producing syngas using the same

A composite oxide for a hydrocarbon reforming catalyst, having a composition represented by the following formula (I),

• aM.bCo.cNi.dMg.eCa.fO (I)
• wherein a, b, c, d, e and f are molar fractions,
• a+b+c+d+e=1,
• 0.0001<a≦0.20,
• 0<b≦0.20,
• 0≦c≦0.20,
• 0.001<(b+c)≦0.20,
• 0.60≦(d+e)≦0.9989,
• 0<d<0.9989,
• 0<e<0.9989, and
• f is the number necessary for elements to maintain charge balance with oxygen;
• and
• M is at least one element among the elements of Group 3B and the elements of Group 6A of the Periodic Table,
• the composite oxide is obtained by a process which comprises:
• preparing a mixed solution for impregnation containing a catalytic active component of Co element, or Co and Ni elements, one or more oxidation resistance enhancing components selected from the group consisting of the elements of Group 3B and the elements of Group 6A of the Periodic Table, and one or more additive metal components selected from the group consisting of Ca and Mg;
• impregnating a carrier formed from a porous molded body selected from magnesia or a composite of magnesia and calcia, with the mixed solution for impregnation;
• drying the carrier impregnated with the mixed solution for impregnation;
• and
• calcining the dried carrier in an oxidizing atmosphere.