Optimizing CO₂ electroreduction: theoretical insights for enhancing efficiency across elementary steps

The electrochemical CO₂ reduction reaction (CO₂RR) can convert CO₂ emissions into valuable fuels and chemicals, offering a promising pathway to close the carbon cycle. However, existing CO₂RR systems face challenges in holistically optimizing interdependent elementary processes, such as adsorption, electron-proton transfer, and mass transport, resulting in unavoidable trade-offs between selectivity, activity, and stability. To address these limitations, a thorough analysis of these elementary steps is essential, supported by theoretical frameworks to guide the design of electrocatalytic systems. By systematically optimizing each process, CO₂RR performance can be significantly enhanced. This review provides a comprehensive overview of the theories and applications governing elementary steps in CO₂RR systems for fine-tuning both catalysts and their near-catalyst environments. The deactivation mechanisms of electrocatalysts are discussed, along with strategies to enhance their stability. Furthermore, alternative anodic reactions that enhance the energy efficiency of the associated system are outlined, along with experimental methodologies for investigating CO₂RR mechanisms. Finally, the review critically assesses the challenges and future prospects in CO₂RR research. Through this in-depth analysis, the review advances the understanding of key theoretical principles and their practical applications in CO₂RR, offering valuable insights for the design and industrial implementation of electrocatalytic CO₂RR systems.