Zhongnan Ling, Yaoyu Yin, Weihai Ni, Sangseok Yu, Jiankang Liu, Shuming Zhou, Mingxin Gao, Zhongjun Chen, Guang Mo, Xuehui Wu, Rongjuan Feng, Zhonghua Wu, Xueqing Xing, Xinchen Kang, Buxing Han
Abstract Efficient CO 2 electroreduction to HCOOH in acidic electrolytes remains a great challenge, especially under high current density conditions. In this study, by introducing In 2 O 3 onto the SnO 2 supported on graphene surface, an In 2 O 3 /SnO 2 @rGO‐2 catalyst is constructed that achieves exceptional selectivity (≈98.3% Faradaic efficiency) for converting CO 2 into HCOOH, at a current density 700 mA cm −2 in 0.5 m K 2 SO 4 (pH 1, adjusted with H 2 SO 4 ) with a high CO 2 single‐pass conversion efficiency of 74.1%. In situ spectroscopic evidence combined with theoretical calculations demonstrates that the In 2 O 3 /SnO 2 @rGO‐2 catalyst can modulate the reaction microenvironment to regulate the initial protonation step of the CO 2 RR, thereby promoting the production of HCOOH. Furthermore, the study demonstrates continuous production of pure HCOOH for over 600 hours at 300 mA cm −2 using a solid‐electrolyte reactor with the In 2 O 3 /SnO 2 @rGO‐2 catalyst, achieving an energy conversion efficiency of 31.8%.