Synthesis and electrochemical hydrogen evolution reaction properties of MoS2/Ru heterostructures

Abstract

Two-dimensional layered MoS2 is considered to be a promising electrocatalyst alternative to Pt for water splitting. However, low electronic conductivity and high energy barrier of water adsorption/dissociation of MoS2 during alkaline hydrogen evolution reaction (HER) limit its application in water splitting. In this work, the smoothly anchored of MoS2 nanosheet on carbon cloth (CC) was prepared by one-pot hydrothermal method. The CC can significantly improve the electronic conductivity. Subsequently, the MoS2 nanosheet supported ultra-small Ru nanoparticles were controllably prepared by solvothermal reaction through immersing CC@MoS2 in an ethanol solution containing RuCl3 and finally formed CC@MoS2/Ru heterostructure. Ru can promote water adsorption/dissociation, and then synergistically catalyze HER with MoS2. The CC@MoS2/Ru is characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and transmission electron microscope (TEM), etc. The results show that the MoS2 nanosheets crossedly aligned on the CC, and the ultra-small Ru nanoparticles (average grain diameter of 2.5 nm) are dispersed homogeneously on the MoS2 nanosheets. The CC@MoS2/Ru is working electrode, the graphite rod and Hg/HgO are counter and reference electrodes, respectively. The alkaline HER are tested and the overpotential is only 71.3 mV to achieve the current density of -10 mA·cm-2, the Tafel slope of CC@MoS2/Ru is 104.8 mV·dec-1. The chronopotentiometry is performed at -10 mA·cm-2 to evaluate the stability of CC@MoS2/Ru. After the 35 h, the neglectable potential attenuation can be observed.

Keywords

• mos2/ru heterostructure
• electrocatalysis
• alkaline hydrogen evolution reaction
• synergistic effect