g-C3N4/MoS2 Heterojunction for Photocatalytic Removal of Phenol and Cr(VI)

Abstract

In this study, molybdenum disulfide (MoS2) decorated on graphitic carbon nitride (g-C3N4) heterostructure catalysts at various weight ratios (0.5%, 1%, 3%, 10%, w/w) were successfully prepared via a two-step hydrothermal synthesis preparation method. The properties of the synthesized materials were studied by X-ray diffraction (XRD), attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FT-IR), UV–Vis diffuse reflection spectroscopy (DRS), scanning electron microscopy (SEM) and N2 porosimetry. MoS2 was successfully loaded on the g-C3N4 forming heterojunction composite materials. N2 porosimetry results showed mesoporous materials, with surface areas up to 93.7 m2g−1, while determined band gaps ranging between 1.31 and 2.66 eV showed absorption over a wide band of solar light. The photocatalytic performance was evaluated towards phenol oxidation and of Cr(VI) reduction in single and binary systems under simulated sunlight irradiation. The optimum mass loading ratio of MoS2 in g-C3N4 was 1%, showing higher photocatalytic activity under simulated solar light in comparison with bare g-C3N4 and MoS2 for both oxidation and reduction processes. Based on scavenging experiments a type-II photocatalytic mechanism is proposed. Finally, the catalysts presented satisfactory stability (7.8% loss) within three catalytic cycles. Such composite materials can receive further applications as well as energy conversion.