Shape effect of Pt/CeO2 catalysts on the catalytic oxidation of toluene

The present work elucidated the shape effect of Pt/CeO2 catalysts toward catalytic oxidation of toluene. CeO2 nanorods, nanoparticles, and nanocubes, dominantly exposed {1 1 0}, {1 1 1}, and {1 0 0} facet, respectively, were employed to immobilize Pt nanoparticles with tunable size by the adsorption method. The catalytic oxidation of toluene was evaluated. Their catalytic performance shows significantly support-shape-dependent behaviour, and the Pt/CeO2-r sample exhibits the best catalytic activity due to the best reducibility and highest concentration of surface oxygen vacancies. Furthermore, two types of TOFs based on the Pt dispersion and the concentration of surface oxygen vacancies were calculated, and the results suggest the oxygen vacancies on ceria surface control the reaction rate. In addition, in-situ UV Raman spectroscopy demonstrates that the supply of active oxygen controls the reaction rate and the surface oxygen vacancies play the role to replenish active oxygen species from gaseous phase and accelerate oxygen cycle for the toluene oxidation.