Integrated Cu electrodes with controllable mesopores for CO2-to-C2H4 electrosynthesis

Electrochemical CO 2 reduction (ECR) to produce chemicals and fuel is a promising technique to build a net-zero carbon circular economy. The performance of ECR has largely advanced in the past decade along with the application of gas diffusion electrodes (GDEs). However, the gas-liquid balance in GDEs is highly fragile due to inefficient CO 2 mass transfer in catalyst layers, which is prone to cause the decay of catalytic performance. In this study, integrated Cu electrodes with controllable mesopores are designed and prepared by copolymer mediated electroless deposition. The optimized Cu electrode shows a selectivity of 81 % (including 65 % for C 2 H 4 ) towards C 2+ products, with a maximum C 2+ partial current density of 232 mA∙cm −2 . Further characterization and simulations reveal that the interconnected mesoporous channels stacked by in-situ reduced Cu nanoparticles leads to an improved CO 2 supply near catalytic sites. In addition, a micro-environment boosting the retention, protonation of *CO intermediates and a unique *CO-CHO coupling step is formed. Our findings provide valuable guidance for enhancing mass transfer and C-C coupling in ECR by creating and controlling intrinsic mesoporous structures in catalyst layers.