Three-dimensional porous copper-decorated bismuth-based nanofoam for boosting the electrochemical reduction of CO2 to formate

Bismuth (Bi)-based nanomaterials are considered as promising electrocatalysts for the electrocatalytic CO2 reduction reaction (CO2RR), but it is still challenging to achieve high current density and selectivity in a wide potential window. Herein, Cu-decorated Bi/Bi2O3 nanofoam (P–Cu–BiNF) with a 3D porous network structure was prepared for the first time via a simple fast-reduction method. Characterizations indicate that the introduction of Cu can significantly regulate the microstructure and electronic states of Bi/Bi2O3. Consequently, the as-prepared P–Cu–BiNF exhibits excellent electrocatalytic performance toward the CO2RR. Remarkably, the faradaic efficiency of formate production can exceed 90% in a wide potential range from −0.78 to −1.08 V. Meanwhile, it can also deliver a high formate partial current density of up to 62.7 mA cm−2 at −1.18 V and long-term stability. This work provides a simple but effective way to synthesize advanced Bi-based materials with significantly improved electrocatalytic CO2RR performance.