Combined Theoretical and Experimental Studies of H2 and CO Oxidation over YSZ Surface

The mechanism of H2 and CO adsorption and oxidation on yttriastabilized zirconia, frequently used as electrolyte in solid oxide fuel cell composite anodes, was investigated employing temperature-programmed spectroscopy (TPS) and density functional theory (DFT). In agreement with theory, the experimental results show that interaction of gaseous H2O with YSZ results in dissociative adsorption leading to strongly bound OH surface species. In the interaction of gaseous H2 with an oxygen-enriched YSZ surface (YSZ+O), similar OH surface species are formed as reaction intermediates in the H2 oxidation. In contrast, the interaction of CO with an oxygen-enriched YSZ leads to direct formation of gaseous CO2 via an Eley-Rideal type reaction that was also confirmed by TPS measurements.