Bi 2 O 3 Nanosheets Grown on Multi‐Channel Carbon Matrix to Catalyze Efficient CO 2 Electroreduction to HCOOH

Bi 2 O 3 nanosheets were grown on a conductive multiple channel carbon matrix (MCCM) for CO 2 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 Bi 2 O 3 nanosheets, where the MCCM provides an accelerated electron transfer, increased CO 2 adsorption, and a high ratio of pyrrolic‐N and pyridinic‐N, while ultrathin Bi 2 O 3 nanosheets offer abundant active sites, lowered contact resistance and work function as well as a shortened diffusion pathway for electrolyte.