Interfacial electron transfer induced dual-site synergetic effects boosting formamide synthesis on CuO/In2O3 hollow cubes

Electrochemical C-N coupling reaction, transforming CO 2 and its derivatives (e.g., CH 3 OH, HCOOH) into highly-value-added organic nitrogenous compounds under ambient conditions, is considered as a promising way to reduce the current reliance of chemical production on fossil fuels. Herein, we synthesized CuO/In 2 O 3 hollow cubes for electrochemical synthesis of formamide from CH 3 OH and aqueous ammonia, achieving a Faradaic efficiency (FE) of formamide of as high as 49.05 % (43.06 ± 5.94 % on average), and a yield rate up to 8.43 ± 1.54 g h −1 mg cat −1 at a current density of 120 mA cm −2 , significantly higher than those of the reported catalysts. In-situ Raman spectra and theoretical calculations disclose that *CHO and *NH 2 intermediates are preferentially adsorbed on Cu and In sites, respectively. Electrons transfer between In and Cu via an In-O-Cu bridge, and the synergistic effects between In and Cu promotes the spontaneous coupling between *CHO and *NH 2 intermediates, thus facilitating the formation of C-N bond, and resulting in enhanced activity and selectivity in formamide synthesis. Using ethanol and propanol as C sources, acetamide and propionamide were obtained, respectively, demonstrating the generality of the as-synthesized catalyst. This work provides an effective strategy of constructing synergetic dual active sites to elevate the catalyst performance on amides electrosynthesis.