Electrocatalytic activity of CO2 reduction to CO on cadmium sulfide enhanced by chloride anion doping

Abstract

AbstractThe electrocatalytic CO2 reduction (ECR) to produce valuable fuel is a promising process for addressing atmospheric CO2 emissions and energy shortages. In this study, Cl‐anion doped cadmium sulfide structures were directly fabricated on a nickel foam surface (Cl/CdS‐NF) using an in situ hydrothermal method. The Cl‐anion doping could significantly improve ECR activity for CO production in ionic liquid and acetonitrile mixed solution, compared to pristine CdS. The highest Faradaic efficiency of CO is 98.1 % on a Cl/CdS‐NF‐2 cathode with an excellent current density of 137.0 mA cm−2 at −2.25 V versus ferrocene/ferrocenium (Fc/Fc+, all potentials are versus Fc/Fc+ in this study). In particular, CO Faradaic efficiencies remained above 80 % in a wide potential range of −2.05 V to −2.45 V and a maximum partial current density (192.6 mA cm−2) was achieved at −2.35 V. The Cl/CdS‐NF‐2, with appropriate Cl anions, displayed abundant active sites and a suitable electronic structure, resulting in outstanding ECR activity. Density functional theory calculations further demonstrated that Cl/CdS is beneficial for increasing the adsorption capacities of *COOH and *H, which can enhance the activity of the ECR toward CO and suppress the hydrogen evolution reaction.