Electrocatalytic CO₂ reduction in acidic medium

Electrocatalytic carbon dioxide (CO₂) reduction has been considered as a promising pathway to achieve carbon neutrality. In alkaline or near-neutral medium, considerable catalytic activity has been reached. However, the inevitable reaction of CO₂ molecules with hydroxide ions forms carbonates, leading to low energy efficiency and carbon utilization. CO₂ electrolysis in acidic medium provides a viable alternative to reduce carbonate production and achieve low energy consumption for CO₂ conversion due to the high carbon utilization and low overpotential for anodic oxygen evolution reaction. Herein, we discuss the progress for efficient electroreduction of CO₂ in acidic medium, wherein theory-guided discovery of cations’ actions, rational design of electrode/catalysts, and local pH effect together accelerate the achievement of acidic CO₂ electroreduction. An outlook is provided about the future development of efficient acidic CO₂ electrolysis, which concerns the catalyst/electrode design and catalytic microenvironment optimization for boosting the selectivity of C-C coupling.