Engineering Unsaturated Cu₁-O₃ Coordination to Boost Oxygen Species Activation for Low-Temperature Catalysis in CO Oxidation

The activation of lattice oxygen at low temperatures is essential for heterogeneous catalytic oxidation, but exactly how this is achieved by adjusting the coordination structure of atomic sites is still elusive. Herein, the Cu₁O₃-CeO₂ catalyst with highly dispersed unsaturated Cu₁-O₃ coordination was creatively engineered, which remarkably enhanced the low-temperature oxidation of CO (a typical model reaction) from 12% to 90% at 66 °C compared to conventional CuCeO_x catalyst. The preservation of atomic coordination-deficient Cu sites enables the transfer of electron cloud density from Cu atoms to O atoms, hence, facilitating the activation of lattice oxygen. Further electron transfer from O atom to Cu species results in charge back-donation to form sufficient Cu⁺ and metal per-oxy species, contributing to weaken O-O bonds. We determined that the increasing number of electron donors induced by unsaturated atomic Cu₁-O₃ coordination is an efficient strategy to develop highly active and stable catalysts for lattice oxygen activation. The catalyst synthesis strategies and oxygen activation mechanism demonstrated in this work provide a generalizable platform for the future design of well-defined functional catalysts for low-temperature oxidation reactions.