A Review on Single Site Catalysts for Electrochemical CO 2 Reduction

Abstract Single site catalysts (SSCs), characterized by high atomic utilization and well‐defined active sites, exhibit significant potential in the field of CO 2 electroreduction (CO 2 RR). Typically, SSCs tend to exhibit a 2‐electron transfer reaction in CO 2 RR, and there remain significant challenges in achieving efficient conversion above 2‐electrons (methane (CH 4 ) and multicarbon products(C 2+ ). Therefore, a systematic review is crucial to summarize the recent advancements in single site CO 2 electrocatalysts and their structure‐activity relationship. The discussion begins with the state‐of‐the‐art characterization techniques of SSCs. Then the influence of central atoms, coordination environments, support and metal‐support interactions on catalytic performance of SSCs is discussed in detail. Subsequently, the regulation strategies to improve the activity and selectivity of CH 4 and C 2+ products are discussed. Furthermore, the dynamic evolution of metal active sites and the true nature of active sites during CO 2 RR are also addressed. Finally, the challenges associated with the utilization of SSCs in CO 2 RR for CH 4 and C 2+ product formation are analyzed.