Novel Bifunctional VO Nanosheets Coupled with N-Doped-Carbon Encapsulated Ni Heterostructure for Enhanced Electrocatalytic Oxidation of Urea-Rich Wastewater.

Developing high performance bifunctional transition metal catalysts would be significantly beneficial for electrocatalytic oxidation of urea-rich wastewater. Herein, we synthesize a VO nanosheet anchored N-doped-carbon encapsulated Ni heterostructure (Ni@C-VO/NF) for the reactions of urea oxidation (UOR) and hydrogen evolution (HER). Electrochemical results indicate that it exhibits small potentials of 1.32, 1.39, and 1.43 V for UOR and low overpotentials of 36, 254, and 355 mV for HER at ±10, ± 500 and ±1000 mA cm, respectively. It can work at 100 mA cm for over 72 h as cathode and anode electrode without obvious attenuation, suggesting an outstanding durability. The reason for this behavior could be ascribed to the N-doped-carbon coating structure, the synergetic effects between Ni and VO, and the nano/micro nanosheets architecture self-supported on nickel foam. This work could provide a promising, inexpensive, and green method for the degradation of urea-rich wastewater and hydrogen production.