Search

Layered transition-metal dichalcogenides (TMDs) have recently attracted intense scientific and engineering interest because of their unique semiconducting and opto-electronic properties. We investigated the pressure-induced structural phase transition of layered semiconductor molybdenum disulfide (MoS2) using Raman spectroscopy and studied its metallization using infrared (IR) spectroscopy under both non-hydrostatic and quasi-hydrostatic conditions. Under quasi-hydrostatic and non-hydrostatic conditions, we found that the structural phase transition from 2 Hc stacking to 2 Ha stacking starts at approximately 16 and 21 GPa, respectively, and finishes at ∼35 and ∼41 GPa, respectively. Furthermore, the structural phase transition was followed by a semiconductor-to-metal (S-M) electronic transition. The pressure point of metallization under quasi-hydrostatic conditions is ∼5 GPa lower than that under non-hydrostatic conditions. [ABSTRACT FROM AUTHOR]

MoS 2 /RGO hybrids was successfully synthesized via hydrothermal method. The MoS 2 nanoflakes grown on the surface of the graphene were uniform and compact from the TEM images. Through the HRTEM images, we conclude the layer number of MoS 2 nanoflakes is in the range of 2–6. Photocatalytic experiments have been performed to verify the excellent photocatic performance of MoS 2 /RGO hybrids. The methylene blue (MB) was completely decomposition by MoS 2 /RGO hybrids within 55 and 75 min under the UV and VIS irradiation, respectively. It is much better than the photocatalytic performance of P25 (nano TiO 2 powder, the current commercial photocatalyst), especially under the VIS irradiation. Good photocatalytic stability of MoS 2 /RGO hybrids was proved through the secondary loop test, which further indicates its promising practical applications. We suggest that the excellent photocatalytic capability of MoS 2 /RGO hybrids can be attributed to their enhanced adsorptivity and conductivity because of the synergistic effect between the few layer MoS 2 and the graphene. [ABSTRACT FROM AUTHOR]