Electrochemical Reduction of CO2 to Multicarbon Products: A Review on Catalysts and System Optimization toward Industrialization

The electrochemical reduction of carbon dioxide (CO2RR) offers a viable pathway for achieving a sustainable carbon cycle, enabling the storage of renewable energy in the form of fuels or chemicals. On the path to commercializing this technology, achieving high current density, high selectivity, and long-term operational stability are core requirements, which remain challenges to overcome. This Review summarizes the state-of-the-art efficient CO2RR catalysts for multicarbon products, including modified copper catalysts, copper-based tandem catalysts, hybrid carbon-copper materials, and copper-based alloy catalysts. It critically reviews advanced regulation strategies such as oxidation state and structure regulation, surface modification, and multiphase composites. Furthermore, the architecture optimization of gas diffusion electrodes is summarized to achieve an efficient three-phase interface, focusing on increasing catalytic active sites, improving hydrophobicity, and regulating the flow direction and concentration of intermediates. In addition to catalyst and electrode optimization, this Review also discusses the latest developments in reactor, mainly focus on the improvements for flow reactors and membrane electrode assemblies, aiming to enable better mass and charge transport and concentration control, thereby enhancing the overall reaction efficiency. The underlying mechanisms linking design strategies to CO2RR performance are highlighted, providing direction for the future design of advanced CO2RR systems.