Self-supported system of MoO2@Ni2P heterostructures as an efficient electrocatalyst for hydrogen evolution reactions in alkaline media

Efficient, stable and low-cost catalysts are essential for improving the efficiency of hydrogen evolution reactions. Herein, the MoO2@Ni2P heterostructure electrocatalyst was synthesized in a self-supported system on a carbon paper (CP) by two-step deposition and phosphorization at low temperature. The self-supported nanoarray structure makes the catalyst to effectively and efficiently transfer electrons and exposes more of its active sites. Moreover, the strong interaction between Ni2P and MoO2 helps to effectively optimize the electronic structure. The density of states calculations demonstrate that there is an increase in the density of electronic states near the MoO2/Ni2P Fermi level. This shows that MoO2/Ni2P has fast charge transfer kinetics. MoO2 modulates the d-band center of nickel, resulting in moderate adsorption/desorption of hydrogen. The above results show that MoO2@Ni2P has good hydrogen evolution activity. The experimental results show that the overpotential (η10) of MoO2@Ni2P/CP in the alkaline environment is only 57 mV with a Tafel slope of 61 mV dec-1. It is similar to the commercial noble-metal catalysts and outperforms most reported catalysts.