Cu nanoparticles embedded in fluorinated mesoporous carbon for enhanced CO₂ electroreduction to C₂ products

Abstract

The utilization of renewable electricity to drive the electrochemical CO2 reduction reaction (CO2RR) presents an attractive avenue for achieving carbon neutrality, as it facilitates the conversion of CO2 into valuable chemicals and fuels. However, producing high-energy-density multi-carbon hydrocarbon products (C2+) still suffers from low selectivity, and the process proves highly sensitive to both catalyst structure and electrolyte conditions. Here, we report the synthesis of fluorinated mesoporous carbon-confined copper nanoparticles (Cu@F-MC) via a bottom-up molecular self-assembly and carbonization strategy. The Cu@F-MC catalyst established a two-dimensional (2D) mesoporous structure with well-dispersed 6.5 nm-wide mesopores and a high surface area. The confinement effect of mesoporous carbon enabled the small size and well dispersion of Cu nanoparticles (~ 10 nm). The fluorine-doped structure not only effectively inhibited the side hydrogen evolution reaction, but also modulated the local electronic structures of Cu nanoparticles toward multi-carbon product generation. Thus, the Cu@F-MC exhibited a high current density of 500 mA·cm−2 with an ethanol Faradaic efficiency (FE) of 40% for CO2 reduction in a flow cell, and a prolonged stability with over 50% selectivity for FEC2+ during a 70h continuous electrolysis in the membrane electrode assembly test. This strategy offers a promising approach to concurrently improve the selectivity and stability of copper-based catalysts in CO2RR.