Perovskite-Derived Bismuth with I- and Cs+ Dual Modification for High-Efficiency CO2 -to-Formate Electrosynthesis and Al-CO2 Batteries.

Abstract

Bi-based materials are one of the most promising candidates for electrochemical CO2 reduction reaction (CO2 RR) to formate; however, the majority of them still suffer from low current density and stability that essentially constrain their potential applications at the industrial scale. Surface modification represents an effective approach to modulate the electrode microenvironment and the relative binding strength of key intermediates. Herein, it isdemonstrated that the surface comodification with halides and alkali metal ions from the conversion of Bi-based halide perovskite nanocrystals is a viable strategy to boost the CO2 RR performance of Bi for formate electrosynthesis. Cs3 Bi2 I9 nanocrystals are prepared by a hot-injection method. The as-prepared products feature well-defined hexagonal shape and uniform size distribution. When used as the precatalyst, Cs3 Bi2 I9 nanocrystals are converted to Cs+ and I- comodified Bi. The resultant catalyst exhibits high formate Faradaic efficiency close to 100%, and remarkable partial current density up to 44mA cm-2 in an H-cell and up to 276 mA cm-2 in a flow cell. Moreover, Cs3 Bi2 I9 is used as the cathode catalyst and paired with an Al anode in an Al-CO2 battery for simultaneous CO2 valorization and power generation.