Abstract: The drive of direct-heat-supply type reforming of hydrocarbon at ordinary temperature is necessary in order to realize a self-sustaining, on-site reforming type fuel cell system which does not necessitate the supply of energy from the outside. According to the invention, an oxide, CeO2 or Pr6O11, or a Ce/Zr or Ce/Zr/Y double oxide is used as the oxide containing a rare earth element capable of changing the oxidation number with an active metal and oxygen defects are introduced into the oxide or double oxide by activating the oxide or double oxide with a reducing gas at high temperature. When a reaction gas containing hydrocarbon and oxygen is passed though the catalyst at low temperature, the oxygen defects react with oxygen and thereby return to the original oxide.

Abstract: A hydrocarbon-reforming catalyst comprising a composite oxide having a composition represented by the following formula (I) in which Co, Ni and M are dispersed in the composite oxide and a process for producing a synthesis gas by using the catalyst are provided. 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, f=the number necessary for element to keep charge equilibrium with oxygen. And M is at least one element among Group 3B elements and Group 6A elements in the Periodic Table. The reforming catalyst is able to maintain a high catalytic activity over a long period in reforming hydrocarbons.

Abstract: The drive of direct-heat-supply type reforming of hydrocarbon at ordinary temperature is necessary in order to realize a self-sustaining, on-site reforming type fuel cell system which does not necessitate the supply of energy from the outside. According to the invention, an oxide, CeO2 or Pr6O11, or a Ce/Zr or Ce/Zr/Y double oxide is used as the oxide containing a rare earth element capable of changing the oxidation number with an active metal and oxygen defects are introduced into the oxide or double oxide by activating the oxide or double oxide with a reducing gas at high temperature. When a reaction gas containing hydrocarbon and oxygen is passed though the catalyst at low temperature, the oxygen defects react with oxygen and thereby return to the original oxide.

Abstract: The hydrocarbon-reforming catalyst comprising a composite oxide having a composition represented by the following formula (I) in which Co, Ni and M are dispersed in the composite oxide and a process for producing a synthesis gas by using the catalyst are provided. 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, f=the number necessary for element to keep charge equilibrium with oxygen. And M is at least one element among Group 3B elements and Group 6A elements in the Periodic Table. The reforming catalyst is able to maintain a high catalytic activity over a long period in reforming hydrocarbons.