Plasma-assisted synthesis of porous bismuth nanosheets for electrocatalytic CO₂-to-formate reduction

The electrochemical carbon dioxide reduction (eCO₂RR) to formate, driven by clean energy, is a promising approach for producing renewable chemicals and high-value fuels. Despite its potential, further development faces challenges due to limitations in electrocatalytic activity and durability, especially for non-noble metal-based catalysts. Here, naturally abundant bismuth-based nanosheets that can effectively drive CO₂-to-formate electrocatalytic reduction are prepared using the plasma-activated Bi₂Se₃ followed by a reduction process. Thus-obtained plasma-activated Bi nanosheets (P-BiNS) feature ultrathin structures and high surface areas. Such nanostructures ensure the P-BiNS with outstanding eCO₂RR catalytic performance, highlighted by the current density of over 80 mA cm⁻² and a formate Faradic efficiency of >90%. Furthermore, P-BiNS catalysts demonstrate excellent durability and stability without deactivation following over 50 h of operation. The selectivity for formate production is also studied by density functional theory (DFT) calculations, validating the importance and efficacy of the stabilization of intermediates (*OCHO) on the P-BiNS surfaces. This study provides a facile plasma-assisted approach for developing high-performance and low-cost electrocatalysts.