Facile Synthesis of TiO2/MoS2 Composites with Co-Exposed High-Energy Facets for Enhanced Photocatalytic Performance

Abstract

In this work, with the the H2TiO3 colloidal suspension and MoS2 as the precursors, TiO2/MoS2 composites composed of anatase TiO2 nanocrystals with co-exposed {101} and [111]-facets (nanorod and nanocuboid), {101} and {010} facets (nanospindle), and MoS2 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 pHx-TiO2/MoS2 composites. The photocatalytic degradation efficiency of pH3.5-TiO2/MoS2 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, MoS2, CM-TiO2, pH1.5-TiO2/MoS2, pH5.5-TiO2/MoS2, pH7.5-TiO2/MoS2, pH9.5-TiO2/MoS2, pH11.5-TiO2/MoS2, respectively. The pH3.5-TiO2/MoS2 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 TiO2/MoS2 composite with co-exposed high-energy facets, and make a contribution to designing more efficient and stable photocatalysts.