Controlled synthesis of copper sulfide-based catalysts for electrochemical reduction of CO2 to formic acid and beyond: a review

Converting carbon dioxide (CO2) into value-added chemicals is considered as a promising strategy to mitigate climate change. Among the various CO2 reduction techniques, electrochemical CO2 reduction (ECO2R) using renewable energy sources holds significant potential. Consequently, the design and development of electrocatalysts capable of offering both high performance and cost-effectiveness hold the potential to expedite reaction kinetics and facilitate widespread industrial adoption. In recent years, abundant copper sulfide (Cu/S)-based nanomaterials among various metal-chalcogenides have attracted extensive research interest due to their semiconductivity and low toxicity, enabling them to be used in a wide range of applications in the ECO2R field. This review highlights the progress in engineered Cu/S-based nanomaterials for ECO2R reactions and elaborates on the correlations between engineering strategies, catalytic activity, and reaction pathways. This paper also summarises the controllable synthesis methods for fabricating various state-of-the-art Cu/S-based structures and outlines their possible implementation as electrocatalysts for CO2 reduction. Finally, challenges and prospects are presented for the future development and practical applications of Cu/S-based catalysts for ECO2R to value-added chemicals.