Functional Group Engineering of Single-Walled Carbon Nanotubes for Anchoring Copper Nanoparticles Toward Selective CO Electroreduction to C Products.

Electroreduction of carbon dioxide (CO) is a key strategy for achieving net-zero carbon emissions. Copper (Cu)-based electrocatalysts have shown promise for CO conversion into valuable chemicals but are hindered by limited C product selectivity due to competing hydrogen evolution and ineffective dimerization of adsorbed CO intermediate (CO). Here, a functional-group-directed strategy is reported to enhance selectivity using single-walled carbon nanotubes (SWCNTs) as supports. The catalytic performance of Cu nanoparticles is strongly influenced by the type and density of functional groups on the SWCNTs. Optimized Cu/amine-functionalized SWCNTs achieved a Faradaic efficiency of 66.2% and a partial current density of -270 mA cm for C products within a flow cell, outperforming Cu/SWCNTs and Cu/cyano-functionalized SWCNTs. Density functional theory calculations revealed that the electron-donating amine groups can facilitate electron transfer from the graphite sheet to Cu atoms, thereby shifting the d-band center of Cu upward. This shift enhances CO and its hydrogenation derivative adsorption and promotes water splitting, leading to an increased tendency for the generation of C products. In situ infrared and Raman spectroscopy confirm the enhancement of key CHO intermediate coverage, facilitating C─C coupling. This work provides a molecular framework for exploring interactions between functional groups and active metals in CO electrolysis, offering insights for designing catalysts for a broad range of electrocatalytic processes.