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In this study, transition metal dichalcogenide (TMD) material WS2 and Au nanoparticles were combined with TiO2 to enhance the photocatalytic performance under visible light. The WS2 nanosheets were synthesized from bulk WS2 via ultrasonic process, and the Au nanoparticles were prepared through the reduction reaction from HAuCl4. The composite photocatalysts of WS2/TiO2/Au, TiO2/Au, and WS2/TiO2 were synthesized by a one-step hydrothermal process. The light absorption property of the composites was determined by ultraviolet-visible (UV-vis) photospectroscopy. Surface analysis of WS2 nanosheet, TiO2 nanoparticles, and Au nanoparticles was performed by scanning electron microscopy (SEM). The chemical structure of composites and thickness of WS2 nanosheets were analyzed by Raman spectra. The photocatalytic activity was measured by methylene blue degradation reaction under visible light. These results revealed the photocatalytic behavior of WS2/TiO2/Au, TiO2/Au, and WS2/TiO2 composites, as well as WS2 nanosheets. The WS2/TiO2/Au composite showed improved photocatalytic behavior among all samples. It is believed that the WS2 nanosheet and Au nanoparticle extend the light absorption range from UV region to the visible region, as well as the WS2/TiO2/Au composite reduces the recombination of electrons. This study shows that the enhanced photocatalytic behavior of WS2/TiO2/Au composite can be used as photocatalytic applications in the future. [ABSTRACT FROM AUTHOR]

In this study, the preparation of ternary photocatalyst using a simple hydrothermal method is shown with high performance. A ternary composite consisting of tungsten sulfide (WS 2) nanosheets, titanium oxide (TiO 2) and gold (Au) nanoparticles is used to the extend the visible-light absorption region of TiO2. The morphological and spectroscopic natures of the prepared sample were analyzed using scanning electron microscopy (SEM), Raman spectroscopy and ultraviolet–visible (UV–vis) photospectroscopy. The photocatalysis measurement for photodegradation of methylene blue dye was performed under the visible light. The photocatalytic studies suggest that in the ternary composite, consisting of three materials with different energy levels, the electrons excited form a cycle to lower the probability for the recombination of electron–hole pairs enhancing the property of photocatalytic activity of TiO2. [ABSTRACT FROM AUTHOR]