Atomic-Level Copper Sites for Selective CO<sub>2</sub> Electroreduction to Hydrocarbon
Anxiang Guan, Chao Yang, Qihao Wang, Linping Qian, Jinyuan Cao, Lijuan Zhang, Limin Wu, Gengfeng Zheng
Abstract
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 Cu1 and Cu4 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 Cu1, exhibiting around 200 times more activity than the direct use of copper salt. With increasing Cu addition in the preparation, the Cu4 nanoclusters were in situ formed and C2 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 C2 generation was accelerated by the Cu4 nanoclusters.