Thermochemical compatibility of doped-cerium oxide with various potential substrates in the fuel-reforming environment

X ray diffraction was used to determine the presence of reactions between Sm doped CeO2 (CSO) with a variety of candidate materials in a fuel reforming environment. Those materials exhibiting stability with CSO were then subjected to further testing in air using X ray diffraction and in the fuel reforming environment using thin film electrical measurement techniques. Reaction rates for the reduced set of candidate materials with CSO were determined from thin film resistivity measurements at temperatures equal to and above the expected field conditions. The X ray data suggested that YSZ and MgO may be good substrate materials; however, electrical measurements indicate that MgO is unstable in environments containing water vapor at high temperatures. Further X ray studies on YSZ have shown the formation of a solid solution at temperatures as low as 800°C, but below this temperature the effect is not thermodynamically favorable. Recently published and collected data suggests several possible enhancements of the activity and stability of the catalyst/support system. A novel composite microstructure is proposed that may reduce coking and enhance catalytic activity --Abstract, page iii