Architectural Design for Enhanced C₂ Product Selectivity in Electrochemical CO₂ Reduction Using Cu-Based Catalysts: A Review

Electrochemical CO2 reduction to value-added chemicals and fuels is a promising approach to mitigate the greenhouse effect arising from anthropogenic CO2 emission and energy shortage caused by the depletion of nonrenewable fossil fuels. The generation of multicarbon (C2+) products, especially hydrocarbons and oxygenates, is of great interest for industrial applications. To date, Cu is the only metal known to catalyze the C–C coupling in the electrochemical CO2 reduction reaction (eCO2RR) with appreciable efficiency and kinetic viability to produce a wide range of C2 products in aqueous solutions. Nonetheless, poor product selectivity associated with Cu is the main technical problem for the application of the eCO2RR technology on a global scale. Based on extensive research efforts, a delicate and rational design of electrocatalyst architecture using the principles of nanotechnology is likely to significantly affect the adsorption energetics of some key intermediates and hence the inherent reaction pathways. In this review, we summarize recent progress that has been achieved by tailoring the electrocatalyst architecture for efficient electrochemical CO2 conversion to the target C2 products. By considering the experimental and computational results, we further analyze the underlying correlations between the architecture of a catalyst and its selectivity toward C2 products. Finally, the major challenges are outlined, and directions for future development are suggested.