Interface Engineering of VO x /Ni/Ni 3 N Heterostructures for Electrochemical Urea-Assisted Hydrogen Production.

Electrocatalytic hydrogen generation driven by renewable energy sources is severely limited by the slow oxygen evolution reaction (OER). Urea-assisted alkaline hydrogen production offers a perspective approach. However, the construction of efficient and robust anode catalysts is still challenging. Herein, an amorphous/crystalline VO x /Ni/Ni 3 N-heterostructured catalyst grown on carbon cloth was synthesized and used as a bifunctional electrocatalyst for the hydrogen evolution reaction (HER) and urea electrooxidation reaction (UOR). Benefiting from the electronic modification of intercomponents and abundant active sites, VO x /Ni/Ni 3 N exhibits an excellent electrochemical performance toward the HER and UOR. Theoretical calculations confirmed that the crystalline/amorphous VO x /Ni/Ni 3 N heterostructure has a suitable water dissociation energy and H* adsorption energy, thereby promoting the HER process. When the UOR and HER are integrated into an electrolytic device, VO x /Ni/Ni 3 N requires a potential of 1.40 V to achieve a current density of 10 mA cm -2 .