A versatile heterostructure junction of NiO–C-MoOx (X= 2 & 3) composite electrocatalysts for hydrogen evolution reaction

Abstract

Developing high-density crystal heterostructure interfaces is highly desirable for the hydrogen evolution reaction (HER). For the first time, NiO-modified MoOx heterogeneous structures are created on carbon matrix materials using a solid-state reaction of the precursor. The solid-state reaction method uses a novel concept called “solid solvent” instead of many solvents and is simple, scalable, and less harmful to the environment. The NiO–C–MoO2 catalyst has an active surface of 40.1 m2 g−1. The NiO–C–MoO2 compound showed superior hydrogen evolution reaction (HER) performance compared to NiO–C–MoO3, with a low overpotential of only 170 mV and Tafel slope of 81.1 mV dec−1 vs. reverse hydrogen electrode (RHE). The d-band structure and modulated charge close to the Fermi level are responsible for the enhanced conductivity, increased availability of active sites, and advantageous H+ adsorption sites. This underscores the significance of optimizing the electronic structure of bifunctional electrocatalysts based on transition metals for optimal HER catalytic activity.