Mo-doped Ni/NiO as a highly efficient and stable electrocatalyst for the hydrogen evolution reaction

Ni/NiO is regarded as an ideal candidate material to replace noble metal catalysts due to its good corrosion resistance and excellent hydrogen evolution activity. However, the poor stability of Ni/NiO catalyst in the process of long-term water electrolysis limits its large-scale application. In this study, a facile hydrothermal method was used to successfully synthesize highly active and stable nanoparticulate Mo–Ni/NiO catalysts. Density functional theory (DFT) shows that Mo doping can optimize the charge transfer of Ni/NiO, reduce the d-band center and accelerate the H* dissociation from the catalyst surface. COMSOL numerical simulation further confirmed that the granular structure can enhance the ion concentration and promote H 2 generation. Electrochemical tests showed that the overpotential of Mo–Ni/NiO was only 45 mV when the current density was 10 mA cm −2 in 1 M KOH solution, which was much lower than 158 mV of Ni/NiO. Furthermore, Mo–Ni/NiO exhibited superior stability when operated at a current density of 10 mA cm −2 for 150 h with a reduction of overpotential of only 2 mV. This work provides a simple method for improving the HER activity of catalysts with Mo doping, which provides a new idea for designing catalysts with high activity, excellent stability and low cost. • Mo doping not only enhances electron transfer but also reduces d-band center. • The influence of different shaped catalysts on surface ion concentration has been revealed. • The overpotential of Mo-Ni/NiO was only attenuated by 2 mV after running for 150 h at a current density of 10 mA cm -2 .