A novel α-Fe₂O₃@MoS₂QDs heterostructure for enhanced visible-light photocatalytic performance using ultrasonication approach

Constructing excellent heterojunction to improve the photocatalytic performance of materials is critically important. Herein, we report an effective simple, easy preparation method for α-Fe₂O₃@MoS₂QDs nanocomposite via two two-step process, including hydrothermal and ultrasonication approaches. The as-prepared materials were characterized using X-ray diffraction (XRD), Transmission electron microscope (TEM), TGA, X-ray fluorescence (XRF) and photoluminescence spectra (PL). The refined PXRD patterns of α-Fe₂O₃ photocatalyst confirm the formation of a single trigonal phase of Fe₂O₃ without another phase impurities. When the MoS₂ QDs were coupled with α-Fe₂O₃, the phase was changed to a single monoclinic phase with C 2/C space group and no peaks observed for MoS₂ QDs. Morphological analyses reveal the successful formation of Fe₂O₃@MoS₂QDs nanocomposites with uniform distribution of MoS₂ QDs on the Fe₂O₃ surface. The XRF analysis confirmed the presence of Mo, S, and Fe elements indicating the nanocomposite formation. The Uv–vis results revealed the enhancement of absorption capability of the α-Fe₂O₃@MoS₂QDs material, particularly in the white light region. Very noticeably, the as-prepared α-Fe₂O₃@MoS₂QDs exhibit high photocatalytic activity performance (84%) toward methylene blue (MB) in 1 min under visible light irradiation. The superior photocatalytic performance of the prepared material can be attributed to the enhancement of the light absorption and the high separation efficiency of photogenerated electron-hole pair in Fe₂O₃@MoS₂QDs structure, which confirmed by PL analysis. The mechanism of photocatalytic degradation of MB over Fe₂O₃@MoS₂QDs nanocomposite was suggested. This work provides a new, low-cost and straightforward idea for enhancement of the degradation performance of organic pollutants in water.