Interfacial Engineering and Electrocatalytic Hydrogen Evolution Performance of Ni/TiO2-VO Nanowires Self-supporting Thin Films

In this paper, a self-supporting titanate nanowire thin film was synthesized by a hydrothermal method. After an ion exchange reaction and a high-temperature H-2/Ar(5%) mixture reduction, the Ni nanoparticles modified oxygen-rich vacancy TiO2 nanowire self-supporting films (Ni/TiO2-V-O NFFs) were obtained. During the high-temperature reduction in H-2/Ar atmosphere, abundant oxygen vacancies and low-coordinated Ti3+ sits were generated on the surface of TiO2 nanowires, which lead to the improvement of the electrical conductivity of TiO2 film. In addition, the strong interaction between Ni nanoparticles and TiO2 optimized the electronic structure and promoted the electrocatalytic hydrogen evolution reaction (HER) activity. density functional theory (DFT) calculations revealed that Ni/TiO2-V-O NFFs had optimal Gibbs free energy of hydrogen adsorption (Delta G(H*)). As a result, Ni/TiO2-V-O NFFs exhibited an overpotential of 67 mV at 10 mA/cm(2) in 1 mol/L KOH solution and displayed excellent stability, showing great potential in the field of electrocatalytic HER.