Electrocatalytic reduction of CO2 to useful chemicals on copper nanoparticles

[Display omitted] •High surface area (630 m2.g−1) metallic copper nanoparticles synthesized for electrochemical reduction of CO2.•Total ̴ 58% Faradaic efficiency has been achieved for liquid products.•Faradaic efficiency maintained around 40 ± 5% when reused number of times at −0.8 V (vs. RHE). One of the best options to utilize CO2 is to convert it to useful chemicals, which may lead to economic and environmental benefits. In the present work, highly stable metallic copper nanoparticles (Cu NPs) have been synthesized and characterized by different physio-chemical characterization techniques like X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), Brunauer-Emmet-Teller (BET), etc. The prepared Cu NPs exhibit porous morphology in pure metallic state with high surface area of 630 m2.g−1. From electrochemical experiments, total Faradaic efficiency (FE) for the liquid products reached to ~58% at −0.8 V (vs. RHE) using prepared Cu NPs as an electrocatalyst. The Cu NPs majorly produced formic acid (2.3 mM) with small quantities of acetic acid (13 µM), ethanol (51 µM), and n-propanol (32 µM) under studied conditions. In addition, FE for formic acid remained constant around ~40% at −0.8 V vs. RHE) when reusing the same electrode number of times. The good performance of Cu NPs might be due to the presence of lots of micropores on the surface, which increases CO2 adsorption for its conversion to chemicals.