Pyrochlore-type catalysts for the reforming of hydrocarbon fuels

A method of catalytically reforming a reactant gas mixture, comprising:

• providing a reactant gas mixture comprising hydrocarbons and an oxidant;
• providing a pyrochlore material catalyst comprised of one or more pyrochlores having the composition A2-w-xA′wA″xB2-y-zB′yB″zO7-Δ wherein:
• A is a trivalent ion of an element selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Er, Tm, Yb, Lu, Bi, Sc, Y, In, and Tl,
• A′ is a trivalent ion of an element selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Er, Tm, Yb, Lu, Bi, Sc, Y, In, and Tl, wherein A′ is an element different from A, and wherein 0≦w≦1,
• A″ is a divalent ion selected from the group consisting of Mg, Ca, Sr, and Ba, and wherein 0<x<1,
• B is a tetravalent ion of an element selected from the group consisting of Ti, Cr, Mn, Zr, Mo, Tc, Rh, Pd, Hf, Os, Ir, Pt, Si, Ge, Sn, and Pb,
• B′ is a trivalent ion or a tetravalent ion of an element selected from the group consisting of Mo, Fe, Os, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Re and V, wherein B′ is an element different from B, and wherein 0<y≦1,
• B″ is a divalent ion, a trivalent ion, or a tetravalent ion of an element selected from the group consisting of Mg, Ca, Sr, Ba, Y, Ce, Re, Cr, Ti, Zr, Hf, Ni, Co, V, and Mo, wherein 0≦z<1 and y+z≦1, and where Δ is a number that renders the composition charge neutral,
• where an average ionic radius ratio of ions in A, A′ and A″-site holding 8-fold coordination with oxygen to ions in B, B′ and B″-site holding 6-fold coordination with oxygen is between 1.46 and 1.80;
• contacting the reactant gas mixture with the pyrochlore material catalyst;
• and
• maintaining the reactant gas mixture and the pyrochlore material catalyst at conditions of temperature, pressure and gas flow rate during the contacting to promote a catalytic reforming process and produce a gaseous mixture comprised of at least hydrogen and carbon monoxide.