Specific Metal Nanostructures toward Electrochemical CO₂ Reduction: Recent Advances and Perspectives

Electrochemically converting CO2 (CO2 reduction reaction(CO2RR)) to value-added fuels is an advanced technology to effectively alleviate global warming and the energy crisis. However, thermodynamically high energy barriers, sluggish reaction kinetics, and inadequate CO2 conversion rate as well as poor selectivity of target products and rapid materials degradation severely limit its further large-scale application, which highlights the importance of high-performance electrocatalysts. Metal nanomaterials, due to their intrinsically high but still insufficient reactivity, selectivity, and stability, have been brought to the forefront and have lead to many reviews from various points of view. However, reviews which comprehensively unravel the importance and excellence of specific metal nanostructures and their associated properties for CO2RR are quite limited. To bridge this gap, various specific monometal and bimetal nanostructures are summarized, with an emphasis on the deep understanding of crystal orientation, surface structure, surface crystallography, surface modification, and many associated effects benefiting from the constructed specific metal nanostructures as well as the intrinsic relationships of specific metal nanostructure-property-CO2RR activities. Finally, the challenges and the perspectives to advance CO2RR are proposed to pay particularly more attention to architecture evolution during CO2RR with in situ/operando techniques, high-throughput theoretical computations, and facile synthetic strategies with high yield and production for scale-up applications.