Large-scale synthesis of zinc oxide-supported indium single-atom catalysts for efficient electrocatalytic CO ₂ reduction reaction

Electrocatalytic CO₂ reduction reaction (eCO₂RR) represents a pivotal technology for converting CO₂ into fuels and chemicals using renewable electricity, with formic acid being a highly valued product. This work reports the large-scale synthesis of zinc oxide-supported indium single-atom catalysts (ZnO@In-SACs) by a modified micro-impinging stream synthesis method and investigates its performance for eCO₂RR. We demonstrate that the reconstructed ZnO nanosheet support optimally tunes the electronic configuration of In single-atom sites during electrolysis, leading to a remarkable enhancement in catalytic activity. Optimized ZnO@In-SACs exhibit exceptional selectivity toward formate and outstanding stability in an alkaline flow electrolyzer for eCO₂RR, with a high faradaic efficiency of 85% and a decent durability of 40 hours at a current density of 100 mA cm⁻², surpassing most reported single-atom catalysts. This work provides an efficient large-scale strategy for fabricating catalysts to be utilized in different electrochemical reactions.