Galvanic Replacement Derived Bi-Based Catalysts for Formate Coproduction via Coupled CO2RR and Methanol Oxidation.

Coupling CO2 reduction with thermodynamically favorable anodic oxidation offers a promising route for lowering the energy demand of paired electrosynthesis. Herein, we report a bismuth-based paired electrosynthesis system (Bi NSs/CF || Bi/NF-20) for the simultaneous coproduction of high value formate at both electrodes via cathodic CO2 reduction (CO2RR) and anodic methanol oxidation (MOR). Crucially, these self-supported electrodes are rationally constructed through a spontaneous galvanic replacement strategy, offering a sustainable alternative to conventional energy intensive fabrication. Consequently, the integrated two-electrode electrolyzer operates stably at 3 V for 50 h, yielding a combined FE exceeding 185% and impressive production capacities of more than 400 g kWh-1. Combined in situ Raman spectroscopy and theoretical calculations reveal that the intrinsic electronic properties of the Bi NSs/CF facilitate the rate-determining step by lowering the *OCHO formation barrier, and elucidate the dynamic evolution of active sites during the MOR. This study offers a compelling strategy for designing integrated electrolyzers toward CO2 valorization with high atom economy.