Heterogeneous molecular catalysts for Multi-Electron electrochemical CO2 reduction

Electrocatalytic multi-electron reduction of CO 2 to high-value hydrocarbons represents a promising pathway toward a sustainable energy economy. Molecular catalysts have demonstrated unique advantages in modulating the electronic structure and microenvironment of active sites, providing an ideal platform for mechanistic studies due to their well-defined structures and tunable properties. While researchers have achieved efficient CO 2 reduction to two-electron products such as carbon monoxide and formic acid, research on multi-electron deep reduction C 1 and C 2+ products remains in its early stages. This minireview summarizes recent progress in heterogeneous molecular catalysts for deep reduction of CO 2 to high-value products. Beyond conventional two-electron products, we categorize and compare recent breakthroughs in multi-electron CO 2 reduction, focusing on highly reduced C 1 species (e.g., CH 4 , CH 3 OH) and multi-carbon (C 2+ ) products. The corresponding reaction mechanisms, including key intermediates and rate-determining steps, are systematically discussed. Finally, we outline the major challenges in achieving efficient and selective deep CO 2 electroreduction, such as catalyst stability, selectivity control, and mechanistic complexity. Future research directions, including the design of advanced molecular catalysts, in situ and operando characterization techniques, and reactor optimization, are proposed to advance this critical field toward practical applications.