Oxygen-Vacancy-Induced CeO2/Co4N Heterostructures toward Enhanced pH-Universal Hydrogen Evolution Reactions

Abstract Developing noble-metal-free electrocatalysts toward pH-universal hydrogen evolution reaction (HER) with high-performance is highly desirable for the practical application of electrochemical water splitting. Currently, the major challenge lies in establishing new design concepts to enhance the sluggish alkaline HER kinetics. Herein, we reported the synthesis of oxygen vacancy-rich CeO2 nanoparticles supported on Co4N nanorod arrays (CeO2/Co4N), and its remarkable HER performances and long-term stability. Density functional theory (DFT) and experiment results indicate that the promoted water adsorption/dissociation ability derived from the abundance of oxygen vacancies in CeO2, together with the optimized hydrogen adsorption free energy (ΔG*H) derived from electron transfer between CeO2 and Co4N, contribute to the outstanding HER activity with an overpotential of 30 mV at 10 mA cm-2 under 1.0 M KOH. We believe the present work could provide new insight for rational design of other efficient non-noble metal based HER electrocatalysts and beyond.