Preferential growth of Pt on rutile TiO2 -: art. no. 041403

The characterization of a Pt/TiO2 (Degussa P25) catalyst system using atomic resolution Z-contrast images and electron energy loss spectroscopy has recently revealed that Pt particles have a strong tendency to nucleate on the rutile phase of TiO2 rather than on anatase. Comparative ab initio pseudopotential calculations for Pt and Pt-2 on the stoichiometric and reduced TiO2 surfaces and for oxygen vacancy (V-O) formation energies are performed to address the microscopic origin of this finding. The results, which show that Pt binds more strongly to anatase surfaces, indicate that the selective growth of Pt on rutile must be controlled by the lower formation energy of V-O on rutile and possibly by the stronger tendency of larger Pt particles to nucleate at the V-O sites of rutile compared to anatase.