Cation effects in electrocatalytic reduction reactions: Recent advances

Electrocatalytic reduction reactions, powered by clean energy sources such as solar energy and wind, offer a sustainable method for converting inexpensive feedstocks (e.g., CO 2 , N 2 /NO x , organics, and O 2 ) into high-value-added chemicals or fuels. The design and modification of electrocatalysts have been widely implemented to improve their performance in these reactions. However, bottlenecks are encountered, making it challenging to further improve performance through catalyst development alone. Recently, cations in the electrolyte have emerged as critical factors for tuning both the activity and product selectivity of reduction reactions. This review summarizes recent advances in understanding the role of cation effects in electrocatalytic reduction reactions. First, we introduce the mechanisms underlying cation effects. We then provide a comprehensive overview of their application in electroreduction reactions. Characterization techniques and theoretical calculation methods for studying cation effects are also discussed. Finally, we address remaining challenges and future perspectives in this field. We hope that this review offers fundamental insights and design guidance for utilizing cation effects, thereby advancing their development. This review summarizes and discusses the mechanisms of cation effects, their applications, characterization techniques, and theoretical calculation methods in cation effects, while also offering future perspectives in this research area.