Au3+ Species-Induced Interfacial Activation Enhances Metal-Support Interactions for Boosting Electrocatalytic CO2 Reduction to CO

The interfacial interactions between the metal and support play a crucial role in electrocatalytic CO2 reduction reaction (CO2 RR). In order to promote the strong metal-support interactions (SMSIs) of the interface, herein, we developed a novel synthetic strategy that utilized deposited Au3+ species to induce Au-CeO2 interface activation by electrochemical pretreatment. This unique configuration made Au nano-particles partially be encapsulated by CeO2 and generate a fraction of surface Au species with positive charges. The obtained catalyst exhibited significantly enhanced selectivity and activity in CO2 RR to CO with a high Faradaic efficiency of about 95% under a wide potential range from -0.7 to -1.0 V. This superior performance was attributed to the activated Au-CeO2 interface, over which abundant Au delta+ species and oxygen vacancies generated by SMSIs could promote CO2 activation and then accelerate the formation of the *COOH intermediate in CO2RR The synthetic strategy was extended to other supports including carbon and ZrO2. The existence of abundant Au delta+ species by strengthened metal-support interactions (MSIs) made the CO Faradic efficiency obviously higher than the catalysts prepared by the traditional NaBH4 reduction method and thus gave new catalytic insights for developing robust supported gold nanocatalysts in CO-related important heterogeneous reactions.