Anchoring Ni3S2/Cr(OH)3 hybrid nanospheres on Ti3C2@NF dual substrates for efficient urea electrolysis by ion exchange

Abstract

Urea-assisted hydrogen production is an energy-saving protocol, so it is particularly important to develop high-performance non-noble metal urea oxidation reaction (UOR) catalysts in simple ways. Herein, exploiting the surface electronegativity of Ti3C2, the electrode covering Ti3C2 nanosheets and Ni3S2/Cr(OH)3 nanospheres were synthesized on a nickel foam substrate by electrostatic adsorption and ion exchange for the first time, and both steps were completed within 2 hours at room temperature. The required overpotential are 130 mV and 169 mV at 10 mA·cm− 2 for UOR and hydrogen evolution reaction(HER), respectively. It delivers current density of 10 mA·cm− 2 at 1.52 V in a two-electrode system, and shows excellent stability. The superior performance of electrodes is mainly attributed to the synergy between the Ni3S2 crystals and the Cr(OH)3 amorphous structure, as well as the large adsorption surface and excellent electrical conductivity provided by the double substrate formed by the uniform coverage of Ti3C2 on NF. The mild preparation process contributes excellent electrode stability to the protection of nickel foam structure. The ingenious structural design of Ni3S2/Cr(OH)3-Ti3C2@NF and the facile preparation method provide ideas for the development of low-cost and efficient electrodes with industrial application prospects.