Nitrogen-doped graphene supported copper nanoparticles for electrochemical reduction of CO2

Abstract

Increasing CO2 concentration in the atmosphere causes a negative impact on the global climate. Utilization of CO2 into value-added chemical products by electrochemical reduction method has attracted great attention to reduce the CO2 emissions and achieve net-zero carbon footprints. Herein, we report a nanostructured electrocatalyst consisting of N-doped graphene (NGN) supported Cu nanoparticles (Cu NPs) with high catalytic activity for electrochemical CO2 reduction (ECR). The electrocatalyst was optimized for loading of Cu NPs on NGN. The physico-chemical properties of electrocatalysts were studied by SEM, TEM, Raman spectroscopy, XPS, etc. Characterization results show that the high loading of Cu (30 wt. %) increases the size of Cu NPs due to agglomeration of particles. ECR experiments were carried out in a two-compartment electrochemical cell. High performance liquid chromatography (HPLC) was employed to analyze the liquid products. Amongst all tested electrocatalysts, Cu20/NGN shows the highest activity for ECR in the entire potential range studied. It gives a total 54 % Faradaic efficiency at -1.0 V (vs. RHE) for the liquid products. The study also demonstrates that the electronic and structural properties of the electrode were improved by the addition of Cu NPs on NGN surface, which in turn enhanced the performance of the catalyst as confirmed by potential-controlled electrocatalysis.