Crystal facet-dependent electrocatalytic performance of metallic Cu in CO_(2)reduction reactions

Developing high-performance electrocatalysts for CO_(2) reduction reaction(CO_(2)RR)is crucial since it is beneficial for environmental protection and the resulting value-add chemical products can act as an alternative to fossil feedstocks.Nonetheless,the direct reduction of CO_(2) into long-chain hydrocarbons and oxygenated hydrocarbons with high selectivity remains challenging.Copper(Cu)shows a distinctive advantage that it is the only pure metal catalyst for reducing CO_(2) into multi-carbon(C_(2+))products and the certain facets(e.g.,(100),(111),(111))of Cu nanocrystals exhibit relatively low energy barriers for the formation of specific products(e.g.,CO,HCOOH,CH_(4),C_(2)H_(4),C_(2)H_(5)OH,and other C_(2+) products).Therefore,extensive studies have been carried out to explore the relationship between the facets of Cu nanocrystals and corresponding catalytic products.In this review,we will discuss the crystal facet-dependent electrocatalytic CO_(2)RR performance in metallic Cu catalysts,meanwhile,the detailed reaction mechanisms will be systematically summarized.In addition,we will provide a personal perspective for the future research directions in this emerging field.We believe this review is helpful to guide the design of high-selectivity Cu-based electrocatalysts for CO_(2)RR.