Methanol‐Facilitated Surface Reconstruction Catalysts for Near 200% Faradaic Efficiency in a Coupled System

Abstract The coupling of the carbon dioxide reduction reaction (CO 2 RR) and methanol oxidation reaction (MOR) holds great promise for the energy‐efficient production of HCOO − . However, anode catalysts' limited selectivity (<80%) and stability (<15 h) have impeded electron utilization and HCOO − production rates. To overcome it, copper‐copper(I) oxide‐copper(II) oxide nanowires (Cu─CuO─Cu 2 O NWs) catalysts have been developed, which exhibit exceptional performance in promoting the MOR with a faradic efficiency of nearly 100% at commercially viable current densities, and long stability over 100 h at 100 mA cm −2 . Interestingly, the unique structure of the catalysts, when exposed to methanol, facilitates a transition from Cu/CuO to Cu 2 O. This phenomenon promotes the MOR while inhibiting the competitive oxygen evolution reaction (OER). By coupling the anodic reaction with cathodic CO 2 reduction, the system demonstrates exceptional performance in HCOO − production, achieving an overall faradic efficiency of nearly 200% at 100 mA cm −2 with a low cell voltage of 2.382 V. Techno‐economic analysis indicates that the production costs of HCOOH are ≈US$0.37 and 0.35 kg −1 at 100 and 150 mA cm −2 , respectively, significantly lower than those associated with traditional electrochemical methods.