Au@TiO2 Yolk-Shell Catalysts for Low-Temperature Oxidation and H2 Photoproduction from Water

F. Zaera
University of California, Riverside, US

Keywords: catalysis

Summary:

One of the major challenges in heterogeneous catalysis is the preparation of highly selective and robust catalysts. The goal is to be able to synthesize solids with stable surfaces containing a large number of specific surface sites designed for the promotion of a particular reaction. New synergies between surface-science studies and novel nanosynthesis methodology promise to afford new ways to design such highly selective catalysts in a controlled way. Here we provide a progress report on a project ongoing in our laboratory based on this approach. New metal@TiO2 yolk-shell nanomaterials have been conceived for both regular and photo-induced catalytic applications. These catalysts can promote CO oxidation at cryogenic temperatures, and suggest that in photocatalysis the role of the metal may not be to scavenge the excited electrons produced in the semiconductor upon absorption of light, as commonly believed, but rather to promote the recombination of the adsorbed atomic hydrogen initially produced by reduction of H+ on the surface of that semiconductor.