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

[Display omitted] Efficient, stable and low-cost catalysts are essential for improving the efficiency of hydrogen evolution reactions. Herein, the MoO 2 @Ni 2 P 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 Ni 2 P and MoO 2 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 MoO 2 /Ni 2 P Fermi level. This shows that MoO 2 /Ni 2 P has fast charge transfer kinetics. MoO 2 modulates the d-band center of nickel, resulting in moderate adsorption/desorption of hydrogen. The above results show that MoO 2 @Ni 2 P has good hydrogen evolution activity. The experimental results show that the overpotential (η 10) of MoO 2 @Ni 2 P/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. [ABSTRACT FROM AUTHOR]