Study of the Hydrogen Spillover Effect in Au/Ce0.62Zr0.38O2 Catalyst

S.E. COLLINS, J.M. CÍES, E. DEL RÍO, J.M. PINTADO, S. BERNAL

Turku / Åbo, Finlandia

Congreso; Europacat 8; 2007

At room temperature, under 40 Torr of H2, a 3 wt%Au/Ce0.62Zr0.38O2 catalysts chemisorbs large amounts of hydrogen. The determined (H/Au) ratio, as high as 8.0, and hydrogen surface density, 11.7 H/nm2, show the occurrence of a strong spillover effect. The process is very fast. The appearance of a FTIR band at 2133 cm-1, due to Ce3+,clearly indicates the simultaneous reduction of the ceria-zirconia support. Moreover, as suggested by the observation of H2O, band at 1630 cm-1, part of the hydrogen chemisorbed on the support is consumed in the creation of oxygen vacancies. The H spillover is strongly inhibited by either co-adsorption of CO or a reducing pre-treatment with 5%H2/Ar, at 673 K. These deactivation effects may be reverted by a very mild re-oxidation treatment at room temperature.