Stable Pt Single Atoms and Nanoclusters on Ultrathin CuO Film and Their Performances in CO Oxidation

A series of model catalysts consisting of Pt single atoms and nanoclusters supported by monolayered CuO film grown at Cu(110) were successfully prepared, which could be stabilized well above room temperature and which exhibited a high performance in CO oxidation at temperatures as low as ∼360 K. Combined scanning tunneling microscopy and temperature-programmed desorption measurements directly evidenced that at the initial CO oxidation stage, oxygen vacancy in the CuO lattice was generated at the nearest neighbor of the Pt nanoclusters. The experimental measurements showed that the oxidation activity was inversely proportional to the Pt nanocluster size. In contrast, the Pt single atoms possessed no surface reactivity for the CO oxidation because of the early and complete desorption of CO before its oxidation on the model catalysts commenced.