Cation effects on electrochemical CO2 reduction reaction

Electrochemical CO2 reduction (eCO2RR) to high-value chemicals and fuels, especially oxygenates and long-chain hydrocarbons, are of great interest for industrial applications, as well as offering a feasible strategy to reach the global goal of net-zero carbon emissions. Over the past few decades, research efforts have been focused on the development of both the rational design of electrocatalysts and electrolyzer systems, along with understanding the underlying mechanisms behind the electrolyte environment (e.g., cations, anions, and pH effects) on eCO2RR. In this review, we summarize recent progress on investigating the intriguing cation effect which steer the challenging eCO2RR toward the desirable directions. Although several hypotheses have been proposed but no consensus has been reached on the underlying mechanism of cation effects toward the eCO2RR. We overview the complex nature of cation effect to modify the electrode and electrolyte interface for converting CO2 efficiently to the target products based both on the latest experimental and computational findings, and provide our viewpoint of future directions and possible strategies in this topic for further improving the eCO2RR performance.