MoS₂ Nanosheets on MoNi₄/MoO₂ Nanorods for Hydrogen Evolution

Abstract

Active electrocatalytic electrodes have been long searched as potential alternatives to platinum-free electrodes for the hydrogen evolution reaction (HER). Here, we report the development of a hybrid nanostructure of two-dimensional (2D) MoS2 nanosheets grown on MoNi4/MoO2 nanorods as a synergistic nanostructure for the hydrogen evolution reaction. The nanostructure is unique as it is composed of vertically grown few-layer atomically thin MoS2 nanosheets supported on MoNi4/MoO2 nanorods with an extraordinarily high surface area. Structural and morphological characterizations illustrate that the 2D MoS2 nanosheets were uniformly coated on the MoNi4/MoO2 nanorods via a facile hydrothermal process. The distinct phase formation, surface compositions, and bonding states confirm the structural integrity and compositional homogeneity between MoS2 and MoNi4/MoO2 nanorods in the synergistic nanostructures. Electrochemical characterizations showed that the MoS2:MoNi4/MoO2 electrodes exhibited a narrower Tafel slope (67 mV dec–1) and a lower overpotential (η10 = 155.6 mV) compared to the pristine MoS2, thereby accelerating hydrogen evolution reactions in an alkaline medium. Also, the synergistic nanostructure-based electrode showed faster charge transport for the HER compared to pristine 2D MoS2 while exhibiting a higher number of the catalytically active sites for the accelerated charge transfer process. The synergistic MoS2:MoNi4/MoO2 nanostructure electrode shows more than 8 h stability with enhanced HER performance.