In-Situ Hydrogen-Bond Tailoring To Construct Ultrathin Bi2O2O/Bi2O2(OH)(NO3) Nanosheets: Interactive CO2RR Promotion and Bismuth-Oxygen Moiety Preservation

Bismuth-oxygen moieties are beneficial for high-efficiency electrochemical CO2 reduction (CO2RR) to produce formate; however, preserving bismuth-oxygen moieties while applying a cathodic potential is challenging. This work reports the preparation of ultrathin Bi2O2O/Bi2O2(OH)(NO3) nanosheets (BiON-uts) by in-situ tailoring of hydrogen bonds in a Bi2O2(OH)(NO3) precursor. The BiON-uts exhibits a formate faradaic efficiency of 98 % with higher partial current density than that of most reported bismuth-based catalysts. Mechanistic studies demonstrate that the ultrathin nanosheet morphology facilitates ion-exchange between BiON-uts and the electrolyte to produce Bi2O2CO3 as intermediate, and adsorption of CO2 with surface Bi2O2O. DFT calculations reveal that the rate-limiting first electron transfer is effectively improved by the high electron affinity of Bi2O2CO3. More importantly, high-efficiency CO2RR in turn protects the bismuth-oxygen moieties from being reduced and thus helps to maintain the excellent CO2RR activity. This work offers an interactive mechanism of CO2RR promotion and bismuth-oxygen moiety preservation, opening up new opportunities for developing high-performance catalysts.

Automated summary

This study demonstrates the preparation of ultrathin Bi2O2O/Bi2O2(OH)(NO3) nanosheets with in-situ tailored hydrogen bonds, which exhibit high-efficiency formate production in electrochemical CO2 reduction. The preservation of bismuth-oxygen moieties contributes to the excellent CO2RR activity.