Effects of Platinum Group Metals on MoS₂Nanosheets for a High-Performance Hydrogen Evolution Reaction Catalyst

Recently, transition-metal dichalcogenides such as MoS2 have been considered for application in hydrogen evolution catalysis. However, its use in the form of a single MoS2 material is limited owing to its low charge-transfer rate. In this study, a MoS2-Pd-Pt catalyst was fabricated on carbon paper using a simple two-step synthesis method. MoS2 and MoS2-Pd were synthesized via a simple hydrothermal method, and a small amount of Pt was electrodeposited on the prepared sample using a three-electrode system. The nanostructure of MoS2-Pd has more defects than the structure of MoS2, and the exposure of active sites is high, which is advantageous for the Pt deposition process. In the Pt electrodeposition process, MoS2-Pd exhibited a higher deposition efficiency and stability than MoS2 in an acidic medium. Although an exceedingly small amount of Pt was deposited, the hydrogen evolution reaction (HER) properties of MoS2-Pd-Pt significantly improved compared to those of MoS2-Pd. Moreover, MoS2-Pd-Pt exhibited an excellent catalytic activity with a lower overpotential (-64 mV at 10 mA/cm2) compared to those of MoS2 (-253 mV) and MoS2-Pd (-204 mV), thereby proving it to be a promising electrocatalyst for the HER as an alternative to Pt.