In Situ Transformation of Tin Microparticles to Nanoparticles on Nanotextured Carbon Support Boosts the Efficiency of the Electrochemical CO2 Reduction

Abstract

Developing sustainable, efficient catalysts for the electrocatalytic reduction of CO2 to valuable products remains a crucial challenge. Our research demonstrates that combining tin with nanostructured carbon support leads to a dynamic interface promoting the transformation of microparticles to nanoparticles directly during the reaction, significantly increasing the formate production up to 5.0 mol h-1 g-1, while maintaining nearly 100% selectivity. Correlative electrochemistry-electron microscopy analysis revealed that the catalyst undergoes an in situ self-optimization during CO2 electroreduction. It has been found that changes in the catalyst are caused by the breakdown of Sn particles driven by electrochemical reactions. The process of pulverization typically results in a decrease in the catalytic activity. However, when Sn particles are pulverized and reach approximately 3 nm in size on the surface of the nanotextured carbon support, the efficiency of the catalyst is maximized. This enhancement occurs because the in situ-formed Sn nanoparticles exhibit better compatibility with the nanotextured support. As a result, the number of electrocatalytically active sites significantly increases, leading to a reduction in charge transfer resistance by more than 2-fold and an improvement in reaction kinetics, which is evidenced by changes in the rate-determining step. Collectively, these factors contribute to a 3.6-fold increase in the catalyst’s activity while maintaining its selectivity for formate production.