Atomic bismuth induced ensemble sites with indium towards highly efficient and stable electrocatalytic reduction of carbon dioxide.

Structural reconstruction is commonly observed during electrocatalytic CO reduction (CORR) process. However, the proper modulation of interface and defect sites remains challenging with the mechanism understanding to realize the favorable electrocatalysis. Herein, the atomic bridging of bismuth with indium atoms is elaborately designed for improving electrocatalysis of CORR via electrochemical reduction and in situ anchoring strategy. As revealed by in situ structure analysis and theoretical studies, the ensemble sites supported on carbon matrix enable the charge density gradient to significantly promote the adsorption of OCHO intermediate by the regulation of σ bonding and π back-donation. Consequently, such unique electrocatalyst achieves the high formate faradaic efficiency of 95.1% over the entire potential range tested and the long-lived stability for 9 d. With coupling of CORR, the solar-driven full cell demonstrates the spontaneous production of formate and 2,5-furandicarboxylic acid via the efficient oxidation of 5-hydroxymethylfurfural with an outstanding yield of 88.2%, highlighting the impressive solar-to-fuel conversion selectivity. Monitoring and understanding the intrinsic active sites of biatomic bridge are crucial to elucidate the synergic electrocatalysis for rationally designing high-performance electrocatalysts.