XPS and Raman study of the active-sites on molybdenum disulfide nanopetals for photocatalytic removal of rhodamine B and doxycycline hydrochlride.

Molybdenum disulfide (MoS) nanopetals were successfully synthesized by hydrothermal method (sample without sintering) and then sintered at different temperature (sintered samples). The products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen (N) adsorption analyses for Brunauer-Emmett-Teller (BET) specific surface area measurements, X-ray photoelectron spectrum (XPS) and Raman spectrum. XRD pattern indicated that the samples can be indexed to hexagonal phase 2H-MoS. SEM and TEM images showed that the sintered MoS nanopetals had sizes ranging from 150 to 300 nm with almost the same morphology. The pore structure and surface area were nearly the same for the three sintered MoS nanopetals. Interestingly, XPS and Raman spectra implied that there was a few 1T-phase in the MoS nanopetals which enhanced the photocatalytic performance greatly when sintered at low temperature.