Bi₂O₃ Nanosheets Grown on Multi‐Channel Carbon Matrix to Catalyze Efficient CO₂ Electroreduction to HCOOH

Abstract

Bi₂ O₃ nanosheets were grown on a conductive multiple channel carbon matrix (MCCM) for CO₂ RR. The obtained electrocatalyst shows a desirable partial current density of ca. 17.7 mA cm^-2 at a moderate overpotential, and it is highly selective towards HCOOH formation with Faradaic efficiency approaching 90 % in a wide potential window and its maximum value of 93.8 % at -1.256 V. It also exhibits a maximum energy efficiency of 55.3 % at an overpotential of 0.846 V and long-term stability of 12 h with negligible degradation. The superior performance is attributed to the synergistic contribution of the interwoven MCCM and the hierarchical Bi₂ O₃ nanosheets, where the MCCM provides an accelerated electron transfer, increased CO₂ adsorption, and a high ratio of pyrrolic-N and pyridinic-N, while ultrathin Bi₂ O₃ nanosheets offer abundant active sites, lowered contact resistance and work function as well as a shortened diffusion pathway for electrolyte.