Electrocatalytic CO2 Reduction into Value-Added Chemicals: Selectivity Tuning, Efficiency Improvement, and Scalability Challenge.

The electrocatalytic CO2 reduction reaction (CO2RR) offers a sustainable pathway to convert CO2 into value-added chemicals. However, a systematic categorization of the resulting chemical products, along with comprehensive strategies toward high efficiency and selectivity of CO2RR has yet to be fully established. Herein, this review systematically summarizes recent advances in CO2RR, covering products from C1 compounds to C2+ chemicals generated via C-C coupling. Subsequently, special emphasis is placed on steering post-coupling pathways to selectively produce ethylene or ethanol, as well as mechanisms for carbon-chain extension toward C3 products like n-propanol. Moreover, multifactor strategies to enhance CO2RR efficiency, including suppressing hydrogen evolution, rational catalyst design, electrolyte microenvironment modulation, and flow cell reactor integration are dissected. Finally, key scientific challenges and techno-economic barriers of this carbon-neutral technology are highlighted.