Ni3S2/Ni Heterostructure Nanobelt Arrays as Bifunctional Catalysts for Urea-Rich Wastewater Degradation

Urea electrolysis is a cost-effective method for urea-rich wastewater degradation to achieve a pollution-free environment. In this work, the Ni3S2/Ni heterostructure nanobelt arrays supported on nickel foam (Ni3S2/Ni/NF) are synthesized for accelerating the urea oxidation reaction (UOR) and hydrogen evolution reaction (HER). It only needs ultralow potentials of 1.30 V and -54 mV to achieve the current density of +/- 10 mA cm(-2) for UOR and HER, respectively. Meanwhile, the overall urea oxidation driven by Ni3S2/Ni/NF only needs 1.36 V to achieve 10 mA cm(-2), and it can remain at 100 mA cm(-2) for 60 h without obvious activity attenuation. The superior performance could be attributed to the heterostructure between Ni3S2 and Ni, which can promote electron transfer and form electron-poor Ni species to optimize urea decomposition and hydrogen production. Moreover, the nanobelt self-supported structure could expose abundant active sites. This work thus provides a feasible and cost-effective strategy for urea-rich wastewater degradation and hydrogen production.

Automated summary

In this study, Ni3S2/Ni heterostructure nanobelt arrays supported on nickel foam were synthesized for accelerating urea oxidation reaction and hydrogen evolution reaction. The heterostructure between Ni3S2 and Ni was found to optimize urea decomposition and hydrogen production, providing a feasible and cost-effective strategy for urea-rich wastewater degradation and hydrogen production.