Facile Synthesis of TiO 2 /MoS 2 Composites with Co-Exposed High-Energy Facets for Enhanced Photocatalytic Performance.

In this work, with the the H 2 TiO 3 colloidal suspension and MoS 2 as the precursors, TiO 2 /MoS 2 composites composed of anatase TiO 2 nanocrystals with co-exposed {101} and [111]-facets (nanorod and nanocuboid), {101} and {010} facets (nanospindle), and MoS 2 microspheres constructed by layer-by-layer self-assembly of nanosheets were hydrothermally synthesized under different pH conditions. The characterization has been performed by combining X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectra, and UV-visible absorption spectrum analyses. The photocatalytic degradation of rhodamine B (RhB) in an aqueous suspension was employed to evaluate the photocatalytic activity of the as-prepared pH x -TiO 2 /MoS 2 composites. The photocatalytic degradation efficiency of pH3.5-TiO 2 /MoS 2 composite was the highest (99.70%), which was 11.24, 2.98, 1.48, 1.21, 1.09, 1.03, 1.10, and 1.14 times that of Blank, MoS 2 , CM-TiO 2 , pH1.5-TiO 2 /MoS 2 , pH5.5-TiO 2 /MoS 2 , pH7.5-TiO 2 /MoS 2 , pH9.5-TiO 2 /MoS 2 , pH11.5-TiO 2 /MoS 2 , respectively. The pH3.5-TiO 2 /MoS 2 composite exhibited the highest photocatalytic degradation rate, which may be attributed to the synergistic effects of its large specific surface area, suitable heterojunction structure, and favorable photogenerated charge-separation efficiency. This work is expect to provide primary insights into the photocatalytic effect of TiO 2 /MoS 2 composite with co-exposed high-energy facets, and make a contribution to designing more efficient and stable photocatalysts.