| Abstract Scope |
Electrochemical CO₂ reduction (ECO2RR) offers a promising route to utilize CO₂ emissions from the iron&steel industry. While high product selectivity for CO (>99%) and formate (>95%) has been achieved, direct CO₂ gas reduction suffers from low utilization efficiency. Bicarbonate reduction was proposed to address this limitation, but its selectivity remains significantly low. We developed a series of catalysts that dramatically enhance bicarbonate reduction efficiency. Specifically, in an H-cell configuration, our catalysts achieve >50% FE, surpassing the state-of-the-art Sn catalyst performance of ~10%. Using operando spectroscopy, we tracked the phase and chemical composition evolution of Sn- and Bi-based catalysts during electrolysis, comparing it with the electrochemical process. Although the terminal evolution state is primarily thermodynamically determined, we observed the persistence of metal-oxygen bonds even at highly negative potentials. Based on these insights into the CO₂ reduction mechanism, we propose an optimized catalyst composition. |