Two-dimensional z-type MoS2/g-C3N4 semiconductor heterojunction nanocomposites for industrial methylene blue dye degradation under daylight

Abstract

The photocatalytic degradation of textile dyes by graphitic carbon nitrides (g-C3N4) under sunlight has received increased attention. Nevertheless, the photocatalytic application of g-C3N4 is still limited by its faster charge carrier recombination. To overcome this obstacle, this research has used an impregnation approach to deposit thin-layered molybdenum disulfide (MoS2) on g-C3N4. The crystallinity, morphology, chemical composition, and structural defects of the resulting two-dimensional (2D) z-type MoS2/g-C3N4 semiconductor heterojunction nanocomposite were investigated by XRD, SEM, EDAX, HRTEM, XPS, Raman, and FT-IR techniques. The microscopic images clearly show that (i) g-C3N4 is densely covered by MoS2, and (ii) the g-C3N4 and MoS2 interface. Using industrial dye, Methylene Blue (MB), the photocatalytic degradation competency of 5% MoS2/g-C3N4 and 10% MoS2/g-C3N4 nanocomposites was examined under natural sunlight. The homogeneous distribution of the MoS2 layer on the g-C3N4 surface helps significantly to reduce the charge carrier recombination during the photocatalytic process. The Mott-Schottky and impedance measurements demonstrate a more active site for photogenerated electron-hole pair and efficient charge separation for enhanced photocatalytic process, which is consistent with the optical property results. Based on the findings, we confirm that the as-prepared MoS2/g-C3N4 nanocomposites outperformed bare MoS2 and g-C3N4 in terms of MB degradation (100%).