Accelerated hydrogen evolution reaction in Ni3P/MoP2/MoO2 tri-phase composites with rich crystalline interfaces and oxygen vacancies achieved by plasma assisted phosphorization

Abstract

A plasma assisted phosphorization method has been developed for preparation of multi-phase materials with rich crystalline interfaces and oxygen vacancies. Specifically, P-NiMoP nanorods (NRs) comprising tri-phases of MoP₂, Ni₃P and MoO₂ have been synthesized by plasma-assisted phosphorization of NiMoO₄ NRs. The specific features of the plasma technique provide P-NiMoP NRs with rich crystalline interfaces and oxygen vacancies in MoO₂. P-NiMoP NRs are demonstrated to be a stable and efficient catalyst for the hydrogen evolution reaction (HER). They only need overpotentials of 3 and 162 mV to drive current densities of 10 and 150 mA cm⁻², both of which are lower than those of Pt/C. The DFT calculations indicate that the tri-phase structure with rich crystalline interfaces and oxygen vacancies plays an important role in the high catalytic activity of P-NiMoP NRs. It promotes a strong electronic coupling between MoP₂, Ni₃P and MoO₂, which facilitates H₂O adsorption and dissociation and reduces the |ΔG_H*| value.