Ultrahigh activity of molybdenum/vanadium-doped Ni-Co phosphides nanoneedles based on ion-exchange for hydrogen evolution at large current density

[Display omitted] •NiCo nanoneedle precursor can provide the abundant active sites exposure and better conductivity.•Mo doping can be achieved through ion-exchange (IE) strategy.•Mo-NiCoP/NF has the higher activity than that of Pt/C at high current density (>99 mA cm−2).•The local electron density and hydrogen adsorption energy of Mo/V-NiCoP/NF can adjusted. Heteroatom doping is a promising strategy to optimize the electronic structure of transition metal phosphides so enhancing the hydrogen evolution reaction (HER). However, complex and harsh experimental design is often required to achieve homogeneous doping of corresponding elements while achieving the best regulating effect. Herein, a facile ion-exchange (IE) strategy is applied to dope Mo/V species evenly into Ni-Co phosphides under mild conditions while maintaining the nanoneedle morphology. The electrochemical characterization verifies Mo dopants have a better electronic regulation effect on NiCoP crystal than V dopants, corresponding to the better hydrogen evolution performance of Mo-NiCoP/NF. Notably, due to the highly dispersed nanoneedle morphology, the synergistic effect of Ni-Co phosphides, and the optimized electronic structure, Mo-NiCoP/NF demonstrates a higher activity than that of the noble metal Pt/C at the high current density (>99 mA cm−2). The present work is supposed to open new sights for the development of high-performance catalysts by ion-exchange strategy.