A DFT Study on Heterogeneous Pt/CeO₂(110) Single Atom Catalysts for CO Oxidation

Understanding strong metal-support interactions is crucially important for developing atom-efficient transition metal heterogeneous catalysts. Herein, we performed a density functional theory study of highly dispersed Pt on CeO₂(110). Various surface models are compared in terms of thermodynamic stability, electronic properties and energy diagrams for CO oxidation. Pt prefers square-planar oxygen coordination in all models with a +2 state. The structures with a single Pt atom exhibit a low CO oxidation activity. A higher activity is predicted by replacement of a surface Ce by two Pt atoms. The high activity of this highly stable structure stems from the coordinative unsaturation of one of the Pt atoms and the presence of a neighboring two-fold O atom. The CO oxidation occurs via a Mars-van Krevelen mechanism. A compared to single-atom catalysts based on Pt in interaction with CeO₂(111) emphasizes the strong dependence of catalytic activity on the ceria surface termination.