Methane Chemisorption on Oxide-Supported Pt Single Atom.

Methane chemisorption has been recently demonstrated on the rutile IrO2 (110) surface. However, it remains unclear how the general requirements are for methane chemisorption or complexation with a single atom on an oxide surface. By exploring methane adsorption on Pt1 substitutionally doped on many rutile-type oxides using hybrid density functional theory, we show that the occupancy of the Pt dz 2 orbital is the key to methane chemisorption. Pt single atom on the semiconducting or wide-gap oxides such as TiO2 and GeO2 strongly chemisorbs methane, because the empty Pt dz 2 orbital is located in the gap and can effectively accept σ-electron donation from the methane C-H bond. In contrast, Pt single atom on metallic oxides such as IrO2 and RuO2 does not chemisorb methane, because the Pt dz 2 orbital strongly mixes with the support-oxide electronic states and become more occupied, losing its ability to chemisorb methane. This study sheds further light on the impact of the interaction between a Pt single atom and the oxide support on methane adsorption.