Synthesis of few-layer g-C3N4 nanosheets-coated MoS2/TiO2 heterojunction photocatalysts for photo-degradation of methyl orange (MO) and 4-nitrophenol (4-NP) pollutants

Abstract

A rational design of g-C3N4 incorporated MoS2/TiO2 heterojunction nanocomposites were successfully synthesized by combination of facile hydrothermal approach and solid state reaction method. The XRD results indicated that the heterojunction catalyst shows mixed phase of tetragonal anatase TiO2 and hexagonal MoS2. SEM and TEM results demonstrates that well defined individual spherical shaped morphology with sizes in the range of 20–25 nm was found in the MoS2/TiO2 heterostruture, which is uniformly decorated on the surface of the g-C3N4 nanosheets. The optimum mass ratio of g-C3N4 in TiO2-MoS2 was 5.0 wt% (denoted as CMT5). The prepared catalysts were used to photocatalytic degradation of methyl orange (MO) and 4-nitrophenol (4-NP), and the experiment results show that g-C3N4 assisted MoS2/TiO2 heterojunction composite (CMT5) displayed excellent photocatalytic activity towards MO dye such as outstanding removal efficiency (98%), high apparent constant (0.0612 min−1) and long-term stability. The enhanced photocatalytic activities of g-C3N4@MoS2/TiO2 photocatalysts are attributed to positive synergetic effect of heterostructure between g-C3N4 and MoS2/TiO2 hybrid structure, which not only enlarged spectral response and also enhanced the utilization rate of photons.