Electrochemical Reduction of CO2 to Formate on Nanoparticulated Bi−Sn−Sb Electrodes

Abstract Human activities during the last century have increased the concentration of greenhouse gases in Earth's atmosphere, mainly carbon dioxide (CO 2 ), and the impacts of climate change around the world are becoming more damaging. Therefore, scientific research is needed to mitigate the consequences of atmospheric CO 2 , and, among others, the electrochemical CO 2 conversion to useful chemicals is one of the most interesting alternatives. Herein, different Bi, Sn and Sb systems were synthesised as nanoparticles, supported on carbon (Vulcan XC‐72R) and finally used to manufacture electrodes. The Bi−Sn−Sb nanoparticulated systems and their corresponding electrodes were characterised by TEM, XPS, ICP‐OES and SEM. Electrochemical reduction of CO 2 to formate was performed in an electrochemical H‐type cell in a CO 2 ‐saturated KHCO 3 and KCl solution. The Bi−Sn−Sb electrodes exhibited good activity and selectivity for the CO 2 reduction towards formate. Particularly, Bi 95 Sb 05 /C and Bi 80 Sn 10 Sb 10 /C electrodes showed improved stability compared to previous works, keeping values of formate efficiency over 50 % after 24 h.