Preparation of metal dichalcogenide based nanomaterials for hydrogen evolution reactions

Abstract

Molybdenum disulfide (MoS2) nanosheets of 10 ± 2 nm in thickness loaded on reduced graphene oxide (rGO) paper were fabricated using a one-step solvothermal method. Differing concentration of tri-octylphosphine (TOP) were used during the fabrication process to determine the effects on the resultant MoS2/rGO system. Scanning electron microscopy (SEM) reveals an abundance of MoS2 self-assembled edges on the rGO paper. Energy-dispersive X-ray spectroscopy (EDX) also confirmed the presence of MoS2 nanosheets on the rGO paper. X-ray diffraction (XRD) patterns also showed that the MoS2 exists in an amorphous or nanosheet form. The resultant MoS2/rGO papers were tested for hydrogen evolution reaction (HER) and an average Tafel slope of 54 mV/decade at an overpotential of -0.15V was achieved for all samples. After conducting a stability test on all samples, the results showed that adding more than 2μl of TOP in 20ml of solution, TOP stabilizes the MoS2 adhesion to the rGO paper and exhibits good stability with negligible current losses. This method showed itself to be an easily reproducible method where highly efficient MoS2 based HER catalysts could be developed.