Electronic tailoring of Ni–NbB2 nanorods via molten salt synthesis for high-efficiency alkaline hydrogen evolution

Abstract

The design of efficient and durable electrocatalysts for enhancing the kinetics of the hydrogen evolution reaction (HER) in alkaline water electrolysis is a significant challenge. Borides have attracted extensive attention due to their excellent corrosion resistance and unique structures. In this study, NbB₂ was synthesized by the molten salt method, and then a metal nickel source was incorporated into the synthesized NbB₂ to prepare a nickel-doped NbB₂ electrocatalyst (Ni–NbB₂) with a nanorod structure. Notably, Ni–NbB₂ exhibited an overpotential of only 239 mV at a current density of 10 mA cm⁻², significantly lower than that of pure NbB₂ (562 mV), and also demonstrated long-term stability. The doping of metal nickel regulated the electronic structure of the metal Nb on the catalyst surface, accelerating the kinetics of the HER reaction. Moreover, the doping of Ni increased the number of catalytic active sites, promoting the full contact between the electrolyte and the catalytic reaction sites and accelerating the charge transfer rate. These findings open up new possibilities for enhancing the HER catalytic activity of metal borides through the strategy of heterometal doping.