electrocatalytic activity

reduction reaction

faradaic efficiency

density ma

activity selectivity

Applied catalysis. B, Environmental

Pulse electrodeposition is a facile technique to control the shape of deposition. With syngergy of 2D Bismuth nanosheets from pulse electrodeposition and hollow fiber gas flow-through, advance electrodes for aqueous CO 2 reduction are preapared. A thermal treatment to to maximize active sites and improves surface wettability of nanosheets resulted in highest formate current density in bicarbonate electrolyte was achieved. • Uniform Bi nanosheets were electrodeposited on hollow fiber gas diffusion electrode. • Bi nanosheets showed significantly enhanced electrocatalytic active surface area. • Low-temperature thermal treatment boosted wettability/roughness of Bi nanosheets. • The highest current density of formate formation in bicarbonate media was obtained. Gas-phase CO 2 electrochemical reduction reaction (CO 2 RR) requires advanced gas diffusion electrodes (GDEs) for efficient mass transport. Meantime, engineering catalyst nanostructure and tuning surface wettability are decisive to enhance three-phase interfaces formation. Herein, Bi-based nanosheets are uniformly grown on flow-through Cu hollow fiber GDE (HFGDE) to benefit from the unique shape of HFGDEs, and abundant active surface area of nanosheets. Pulse electrodeposition is used to replenish Bi 3+ ions in the vicinity of HFGDEs for uniform growth of Bi nanosheets. Further, thermal oxidation of nanosheets not only maximized the active sites and improved surface wettability but also induced Bi/Bi 2 O 3 junctions in nanosheets, enhancing formate production via switching the rate-limiting step from the initial electron transfer to hydrogenation. Consequently, a current density of 141 mA cm −2 at -1 V vs. RHE with formate faradaic efficiency of 85 % and over six times greater catalyst mass activity compared to bulk particle shaped Bi, were achieved, outperforming other reported Bi-based GDEs used for formate production in bicarbonate electrolytes. This comes from less charge-transfer resistance, higher surface roughness, and improved wettability of Bi nanoshee...

Shape-tuned electrodeposition of bismuth-based nanosheets on flow-through hollow fiber gas diffusion electrode for high-efficiency CO2 reduction to formate