Construction of sandwich structured photocatalyst using monolayer WS2 embedded g-C3N4 for highly efficient H2 production

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-C 3 N 4 /WS 2 is proposed. Step one is hydrothermal process producing the layered WO 3 , which is used as the precursor for monolayer WS 2 . While step two involves one-pot calcination process that generates sandwich structured g-C 3 N 4 /WS 2 . 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-C 3 N 4 /WS 2 . Photocatalytic H 2 generation tests show that the optimal H 2 generation rate of g-C 3 N 4 /WS 2 is 599.7 μmol h -1  g -1 (20 mg of photocatalyst), which is about 25 times higher than that of bare g-C 3 N 4 . 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-C 3 N 4 /WS 2 .