Coupling Ni-Cu atomic pair to promote CO2 electroreduction with near-unity CO selectivity.

Abstract

The electrocatalytic reduction of CO2 towards CO is one of the most desirable routines to reduce atmospheric CO2 concentration and maintain a global carbon balance. In this work, a novel porous NiCu-embedded ZIF-derived N-doped carbon nanoparticle (NiCu@NCNPs) catalyst has been identified as an active, highly selective, stable, and cost-effective catalyst in CO2 reduction. A CO selectivity as high as 100% has been achieved on NiCu@NCNPs which is the highest reported to date. The particle current density of CO on NiCu@NCNPs is around 15mAcm-2 under the optimized potential at -0.9V vs. RHE. The NiCu@NCNPs electrode also exhibits excellent stability during the five sequential CO2 electroreduction experiments. The superior catalytic performance of NiCu@NCNPs in CO2RR can be related to its microstructure with high electrochemical surface area and low electron transfer resistance. Furthermore, a kinetic analysis has shown the formation of intermediate *COOH is the rate-determining step in CO2RR towards CO. According to the results of density functional theory (DFT) calculations, a low Gibbs-free energy change (∆G) for the rate-determining step leads to the enhanced catalytic performance of CO2RR on NiCu@NCNPs.