Dual Activation of Molecular Oxygen and Surface Lattice Oxygen in Single Atom Cu₁/TiO₂ Catalyst for CO Oxidation

Abstract

The in-depth mechanism on the simultaneous activation of O₂ and surface lattice O^2- on one active metallic site has not been elucidated yet. Herein, we report a strategy for the construction of abundant oxygen activation sites by rational design of Cu₁ /TiO₂ single atom catalysts (SACs). The charge transfer between isolated Cu and TiO₂ support generates abundant Cu^I and 2-coordinated O_lat sites in Cu₁ -O-Ti hybridization structure, which facilitates the chemisorption and activation of O₂ molecules. Simultaneously, the Cu₁ -O-Ti induced TiO₂ lattice distortion activate the adjacent surface lattice O^2- , achieving the dual activation of O₂ and surface lattice O^2- . The Cu₁ -O-Ti active site switches the CO oxidation mechanism from Eley-Rideal (80 °C) to Mars-van Krevelen route (200 °C) with the increase of reaction temperature. The dual activation of O₂ and surface lattice O^2- can by modulating the electron properties of SACs can boost the heterogeneous catalytic oxidation activity.