Rise of nano effects in electrode during electrocatalytic CO₂ conversion

The electrocatalytic conversion of CO₂ into value-added fuels has received increasing attention as a promising way to mitigate the atmospheric CO₂ concentration and close the broken carbon-cycle. Early studies, focused on polycrystalline metal electrodes, outlined in detail the overall trends in the catalytic activity and product selectivity of pure metals; however, several inherent limitations were found, such as low current density and high overpotential, which hindered electrocatalytic CO₂ reduction from practical application. Fortunately, the recent development of precisely synthesized nanocatalysts has led to several breakthroughs in catalytic CO₂ conversion. By carefully controlling the thermodynamic adsorption energies and flow dynamics of reaction intermediates, nanosized electrocatalysts afford more versatile and energetically efficient routes to convert CO₂ into desired chemicals. In this article, we review the state-of-the-art nanocatalysts applied for CO₂ conversion and discuss newly found phenomena at the local environment near the catalyst surface. The mechanistic understanding of these findings can provide insight into the future design of catalysts for the efficient and selective reduction of CO₂.