Nickel incorporated Co9S8 nanosheet arrays on carbon cloth boosting overall urea electrolysis

Abstract

Hydrogen production via water electrolysis is deemed to be a viable strategy to exploit renewable energy and relieve the crisis of energy and environment. Compared with water electrolysis, the introduction of urea not only improves the energy conversion efficiency of urea electrolysis but also makes this process apply in the treatment of sewage treatment. Herein, we highlight a novel bifunctional electrocatalyst of Co9S8 nanosheet arrays grown on carbon cloth with optimal nickel incorporation. Benefited from the incorporation of Ni, the electronic structure of Co9S8 is optimized, resulting in the enhanced electrical conductivity and charge transfer efficiency. The structure of nanosheets endows the 2D charge transfer pathway and exposes more active sites to achieve the robust electrocatalytic activity for overall urea electrolysis simultaneously. The optimal nickel incorporated Co9S8/carbon cloth catalysts display remarkable catalytic activity. It delivers the current density of 10 mA cm−2 with the potential of 1.28 V vs. RHE for urea oxidation reaction (UOR), almost rivalling the state-of-the-art UOR catalysts. Overall urea splitting based on Ni–Co9S8/carbon cloth as bifunctional catalyst is also carried out and only a potential of 1.52 V is required to achieve 10 mA cm−2.