Driving high-efficiency carbon utilization: Acidic CO2 electroreduction

Electrocatalytic carbon dioxide reduction (ECO₂RR) converts the greenhouse gas CO₂ into high-value fuels and chemicals, offering a crucial pathway for achieving a sustainable carbon cycle. Compared to traditional alkaline/neutral systems plagued by severe carbonate deposition leading to low energy efficiency, acidic ECO₂RR fundamentally suppresses carbonate formation, thereby enabling efficient carbon cycling and energy utilization. However, the core challenges of this system lie in the intense competition from the hydrogen evolution reaction (HER), mass transport limitations, and insufficient system stability. Addressing these challenges hinges on modulation across three key aspects: catalysts, electrodes, and electrolytes. This includes suppressing HER and enhancing reaction kinetics through catalyst microenvironment engineering and active site design; optimizing electrode structures and modifying interfaces to improve mass transport and corrosion resistance; and regulating electrolyte composition to stabilize the reaction interface while exploring metal-free cation strategies. Currently, comprehensive reviews detailing strategies across catalysts, electrodes, and electrolytes to promote acidic ECO₂RR remain scarce. Therefore, this review focuses on the acidic ECO₂RR system, systematically summarizing its fundamental principles, key challenges, targeted solutions, performance evaluation metrics, and current development status. It also provides future perspectives aimed at offering fresh insights to advance the development of acidic ECO₂RR.