Cu Site Engineering in Mesoporous N-Doped Carbon Nanoflakes for Enhanced Electrocatalytic Reduction of CO₂

The electrochemical reduction of CO2 (ECO2RR) to value-added chemicals represents a promising strategy for advancing carbon neutrality; yet, the design of highly efficient catalysts remains a central challenge in this field. Herein, we synthesized a mesoporous N-doped carbon nanoflakes loaded with Cu sites using low-cost coal pitch as the carbon precursor, mediated by 2,2′-bipyridine coordination. The material features a three-dimensional hierarchical porous architecture with interconnected channels that enhances the CO2 mass transport and product diffusion kinetics. Crucially, the synergistic interplay between carbon matrix confinement and Cu–N coordination effectively suppresses Cu species migration and aggregation, ensuring exceptional catalytic performance. Density functional theory calculations (DFT) and temperature-programmed desorption (TPD) analysis revealed that high-density Cu–N sites boost C–C coupling for C2 products. When tested in a flow electrolysis cell, the optimized catalyst achieved over 90% total ECO2RR selectivity (51% toward C2 products, including ethylene and ethanol) at 150 mA·cm–2.