Anion-Mediated In Situ Reconstruction of the Bi 2 MoO 6 Precatalyst for Enhanced Electrochemical CO 2 Reduction over a Wide Potential Window.

Electrochemical CO reduction reaction (eCORR) is a viable approach to achieve carbon neutrality. Bismuth-based electrocatalysts demonstrate exceptional selectivity in CO-to-formate conversion, but their reconstruction mechanisms during the eCORR remain elusive. Herein, the reconstruction processes of bismuth molybdate (BiMoO) nanoplates are elucidated during the eCORR. and measurements reveal the partial reduction of BiMoO to Bi metal, forming Bi@BiMoO at negative potentials. Meanwhile, CO ions in the electrolyte spontaneously exchange with MoO in BiMoO. The obtained Bi@BiMoO/BiOCO delivers a formate Faradaic efficiency (FE) of 95.2% at -1.0 V. Notably, high formate FEs (>90%) are maintained within a wide 500 mV window. Although computational calculations indicate a higher energy barrier for *OCHO formation on BiOCO, the prevention of excessive reduction to metal Bi significantly enhances long-term stability. Furthermore, the CO ion exchange process occurs in various 2D Bi-containing precatalysts, which should be emphasized in further studies.