Synergistic Effects of Doping and Strain in Bismuth Catalysts for CO₂ Electroreduction

Doping is a recognized method for enhancing catalytic performance. The introduction of strains is a common consequence of doping, although it is often overlooked. Differentiating the impact of doping and strain on catalytic performance poses a significant challenge. In this study, Cu-doped Bi catalysts with substantial tensile strain are synthesized. The synergistic effects of doping and strain in bismuth result in a remarkable CO₂RR performance. Under optimized conditions, Cu_1/6-Bi demonstrates exceptional formate Faradaic efficiency (>95%) and maintains over 90% across a wide potential window of 900 mV. Furthermore, it delivers an industrial-relevant partial current density of -317 mA cm^-2 at -1.2 V_RHE in a flow cell, while maintaining its selectivity. Additionally, it exhibits exceptional long-term stability, surpassing 120 h at -200 mA cm^-2. Through experimental and theoretical mechanistic investigations, it has been determined that the introduction of tensile strain facilitates the adsorption of *CO₂, thereby enhancing the reaction kinetics. Moreover, the presence of Cu dopants and tensile strain further diminishes the energy barrier for the formation of *OCHO intermediate. This study not only offers valuable insights for the development of effective catalysts for CO₂RR through doping, but also establishes correlations between doping, lattice strains, and catalytic properties of bismuth catalysts.