Selective HCOOH Production over Wide Potential Range via Defective Oxide‐Derived Bismuth

Abstract Electrochemical reduction of CO₂ toward value‐added liquid fuel is a promising route to achieve the carbon neutrality. Especially for CO₂ electroreduction to formic acid production, despite the favorable activity and selectivity can be achieved, unstable Faradaic efficiency (FE) in wide potential range and poor energy efficiency remain the bottlenecks. Herein, this study reports a metallic Bi catalyst (B‐ArH₂‐2) derived from defective Bi₂O₃, which achieves nearly 100% FE for HCOOH production over a broad potential range (−0.7 to −1.1 V) with an outstanding cathodic energy efficiency of 71%. Additionally, B‐ArH₂‐2 displays a high partial current density of HCOOH (j_HCOOH, 27.5 mA cm⁻²) and production rate (475 µmol h⁻¹ cm⁻²) with favorable long‐term stability (20 h).