Unveiling phase-selective α- and β-Bi2O3-derived electrocatalysts for CO2 electroreduction

Summary

Phase engineering to modulate the physicochemical properties of nanostructured metal oxides has shown great potential in electrocatalysis but has rarely been studied for the electrochemical CO₂ reduction reaction (CO₂RR). Herein, we have prepared α-Bi₂O₃ and β-Bi₂O₃ through a facile method with controllable phase transition. Compared to α-Bi₂O₃, the phase-difference-induced physicochemical property change of β-Bi₂O₃ makes it have better CO₂ chemisorption capacity and water dissociation ability than α-Bi₂O₃. This favors fast reaction kinetics for formate formation and leads to better CO₂RR performance of β-Bi₂O₃ than α-Bi₂O₃, achieving a maximum Faradaic efficiency of 98.1% at −1.1 V and good stability of 36 h. Computational results further unravel the exothermic processes of the key intermediate ∗OCHO formation and water dissociation on β-Bi₂O₃. This work underscores the effectiveness of phase engineering of metal oxides in the CO₂RR and provides more opportunities for the intellectual design of highly efficient catalysts to achieve environmental sustainability.