Au 3+ Species-Induced Interfacial Activation Enhances Metal–Support Interactions for Boosting Electrocatalytic CO 2 Reduction to CO

The interfacial interactions between the metal and support play a crucial role in electrocatalytic CO 2 reduction reaction (CO 2 RR). In order to promote the strong metal–support interactions (SMSIs) of the interface, herein, we developed a novel synthetic strategy that utilized deposited Au 3+ species to induce Au–CeO 2 interface activation by electrochemical pretreatment. This unique configuration made Au nanoparticles partially be encapsulated by CeO 2 and generate a fraction of surface Au species with positive charges. The obtained catalyst exhibited significantly enhanced selectivity and activity in CO 2 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–CeO 2 interface, over which abundant Au δ+ species and oxygen vacancies generated by SMSIs could promote CO 2 activation and then accelerate the formation of the *COOH intermediate in CO 2 RR. The synthetic strategy was extended to other supports including carbon and ZrO 2 . The existence of abundant Au δ+ species by strengthened metal–support interactions (MSIs) made the CO Faradic efficiency obviously higher than the catalysts prepared by the traditional NaBH 4 reduction method and thus gave new catalytic insights for developing robust supported gold nanocatalysts in CO-related important heterogeneous reactions.