Highly selective electrochemical CO 2 reduction to formate using Sn@Cu electrocatalyst

The strategy of obtaining value-added products from electrochemical reduction of CO 2 is promising and advantageous over other conventional methods. The present work uses an electrodeposition method to prepare electro-decorated Sn on Cu foam. The physicochemical and morphology analyses were studied using XRD, XPS, and FESEM. The electrocatalytic reduction of CO 2 of the prepared electrocatalyst was successfully demonstrated in 0.5-M KHCO 3 electrolyte in two different cell designs—a conventional H-type cell and an improved cell design by the two parallel-connected electrodes. The formate product formed during CO 2 reduction was identified using NMR, and the faradaic efficiency at different potentials was calculated. The prepared electro-decorated Sn@Cu foam electrode displayed exceptional stability under CO 2 reduction conditions over a period of 20-h duration in a conventional method. We extended our work for continuous CO 2 electroreduction with parallel-connected electrodes to obtain formate at ambient temperature and pressure. The parallel mode was adopted to maximize the active sites so as to achieve maximum product concentration. The formate concentration of 6.12 g L −1 was achieved with electro-decorated Sn@Cu foam electrode on continuous CO 2 reduction in a batch mode setup. The proposed approach of producing formate via batch mode CO 2 reactor at a larger scale would open vistas for the industrialization (scale-up) of the process. Graphical abstract The present work is focused on the preparation of electro-decorated Sn@Cu foam using electrodeposition methods. Electroreduction of CO 2 was carried out using the tin on Cu electrocatalyst. We observed the selective formation of formate. With the improved cell design, we can achieve the formate concentration of 6.12 g L −1 on 20 h of continuous CO 2 electrolysis.