Construction of sandwich structured photocatalyst using monolayer WS2 embedded g-C3N4 for highly efficient H-2 production

摘要

The construction of sandwich structured binary composite can enlarge its specific surface and strengthen the contact of binary interface. This can enhance H-2 generation efficiency of the photocatalyst. In this study, two-step strategy for the preparation of novel sandwich-structured g-C3N4/WS2 is proposed. Step one is hydrothermal process producing the layered WO3, which is used as the precursor for monolayer WS2. While step two involves one-pot calcination process that generates sandwich structured g-C3N4/WS2. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectrometry (ICP-OES), Brunauer Emmett Teller method (BET), and transmission electron microscopy (TEM) are employed to characterize the composition, structure and morphology of g-C3N4/WS2. Photocatalytic H-2 generation tests show that the optimal H(2 )generation rate of g-C3N4/WS2 is 599.7 mu mol h(-1) g(-1) (20 mg of photocatalyst), which is about 25 times higher than that of bare g-C3N4. Moreover, UV-vis diffuse reflectance spectroscopy (UV-vis DRS), photoluminescence (PL) and electrochemical tests are employ to establish possible mechanism of photocatalytic H-2 evolution in sandwich-structured g-C3N4/WS2.