Facile synthesis of a bismuth nanostructure with enhanced selectivity for electrochemical conversion of CO₂ to formate

Electrochemically converting carbon dioxide (CO₂) to formate offers a promising approach for energy conversion and storage. Bismuth is believed to be one of the promising candidates for CO₂ electroreduction, but the poor selectivity and complexity of synthesis limit its real application on a large scale. In this work, a facile one-step-reduction method was developed to prepare a bismuth nanostructure in aqueous solution. Owing to its enhanced reactive sites and exposed crystal plane, the prepared Bi nanostructure exhibits excellent performance for CO₂ electroreduction, which reaches the maximum faradaic efficiency for formate as high as 92% at a potential of -0.9 V versus a reversible hydrogen electrode. Additionally, the large current density and remarkable durability also reveal its high intrinsic CO₂ electroreduction activity. The density functional theory calculation confirms that the formation of intermediate ∗OCHO that finally converts to formate is thermodynamically favorable on Bi high-index planes. We anticipate that such a facile synthesis strategy and excellent electrocatalytic performance of the Bi nanostructure will be easy to scale up, realizing its industrialization applications in CO₂ electrochemical conversion.