Self-assembling solid oxide fuel cell materials: Mesoporous yttria-zirconia and metal-yttria-zirconia solid solutions

A new class of mesoporous (nickel/platinum)-yttria-zirconia materials, denoted meso-(Ni/Pt)YZ, which may have utility as electrode material in solid oxide fuel cells (SOFCs), have been synthesized by aqueous co-assembly of glycometalates and metal complexes with a surfactant template. These materials form as solid solutions with compositions that can be tuned over the range 12-56 atom % yttrium and 10-30 atom % nickel or 1-10 wt % platinum. The microstructure of the channel wall is nanocrystalline yttria-zirconia (YZ) and nickel/platinum is incorporated as metal oxide/metal clusters with diameters comparable to the size of the pores depending on the degree of loading of the metal precursor. Calcination in air of as-synthesized meso-(Ni/Pt)YZ materials causes the channel walls to crystallize and thicken as the imbibed organics are lost. It is the relatively thick, YZ nanocrystalline walls which are believed to be responsible for the impressive 800 degrees C thermal stability of meso-(Ni/Pt)YZ. This new class of binary and ternary mesoporous materials display the highest recorded surface area of any known form of (metal)-yttria-stabilized-zirconia. A narrow mesopore size distribution, nanocrystalline channel walls, and high thermal stability may lead to significant improvements in fuel/oxidant mass transport, oxide ion mobility, electronic conductivity, and charge transfer at the triple-phase-boundary region of SOFC electrodes. It may also enable a reduction in the operating temperature of the SOFC.