Atomic-Level Copper Sites for Selective CO2 Electroreduction to Hydrocarbon

In the aqueous electroreduction of CO2, the competing hydrogen evolution reaction (HER) results in poor product selectivity of the catalyst. To suppress HER, herein, the atomic-level copper sites of Cu-1 and Cu-4 were prepared and stabilized in hydrophobic cyclohexene. The stabilized sites anchored on multiwall carbon nanotubes through chemical interaction, presenting high selectivity of hydrocarbon production in CO2 electroreduction. A large mass activity of CH4 production around 100 000 A.cm(-2).gCu(-1) at -1.8 V vs reverse hydrogen electrode (RHE) was achieved on the catalyst containing Cu-1, exhibiting around 200 times more activity than the direct use of copper salt. With increasing Cu addition in the preparation, the Cu-4 nanoclusters were in situ formed and C-2 hydrocarbon was generated favorably with a mass activity of C2H4 around 10 000 A.cm(-2).gCu(-1) at -1.4 V vs RHE, much higher than the copper bulk with Cu(111) facets. Density functional theory (DFT) calculations disclosed that the dimerization of adsorbed CO intermediates for C-2 generation was accelerated by the Cu-4 nanoclusters.

Automated summary

In the study, high selectivity of product generation in CO2 electroreduction was achieved by stabilizing copper sites on carbon nanotubes. The catalyst containing Cu-1 exhibited high mass activity for CH4 production, while Cu-4 catalyst favored the generation of C-2 hydrocarbons.