Mahdizadeh Rana, Sangpour Parvaneh, Emrooz Hosein Banna Motejadded
Department of Nanotechnology, School of Advanced Technologies, Iran University of Science and Technology, Tehran, Iran.
Department of Nanotechnology and Advanced Materials, Materials and Energy Research Center, Karaj, Iran.
Sci Rep. 2025 Aug 18;15(1):30272. doi: 10.1038/s41598-025-16326-5.
Employing three porous semiconductor particles, the impact of the surface area on dynamic photocatalytic degradation of methylene blue has been investigated under an LED light source. At first, porous ZnS with a relatively high surface area was synthesized via an innovative method in ethanol, which is insoluble for Sulphur precursor (NaS). This semiconductor was used for the synthesis of porous ZnO and ZnS-ZnO nanocomposites through a simple oxidation treatment in the air atmosphere. The characterization of the synthesized compounds was conducted through different techniques including X-ray diffraction, physisorption of nitrogen, simultaneous thermal analysis, field emission scanning and high-resolution transmission electron microscopy, photoluminescence spectroscopy, FT-IR spectroscopy, Mott-Schottky technique, and visible-ultraviolet spectroscopy. Based on the results, the specific surface areas were reported as 165 m g, 35 m g, and 10 m g for ZnS, ZnS-ZnO, and ZnO, respectively. Despite ZnS having a higher bandgap (3.3 eV) and lower charge carrier density (9.21⋅10 cm) than ZnS-ZnO, it exhibits better photocatalytic efficiency which emphasizes on the pronounced impact of surface area on the photocatalytic degradation of the selected dye. The efficiency of ZnS in removing organic pollutants is 88%, while ZnO achieves only 43% removal, and the ZnS-ZnO composite exhibits a removal efficiency of 55%. This superior efficiency of ZnS is further supported by its higher surface area, reduced PL intensity and visible-range emissions due to defect states, along with Mott-Schottky analysis confirming trap states that enhance charge separation under LED light. The degradation followed a dynamic process driven by efficient charge transfer and surface interactions.
采用三种多孔半导体颗粒，研究了在LED光源下比表面积对亚甲基蓝动态光催化降解的影响。首先，通过一种创新方法在乙醇中合成了具有相对较高比表面积的多孔ZnS，乙醇对硫前驱体（NaS）不溶。通过在空气气氛中进行简单的氧化处理，将这种半导体用于合成多孔ZnO和ZnS-ZnO纳米复合材料。通过不同技术对合成的化合物进行表征，包括X射线衍射、氮气物理吸附、同步热分析、场发射扫描和高分辨率透射电子显微镜、光致发光光谱、傅里叶变换红外光谱、莫特-肖特基技术以及可见-紫外光谱。结果表明，ZnS、ZnS-ZnO和ZnO的比表面积分别为165 m²/g、35 m²/g和10 m²/g。尽管ZnS的带隙（3.3 eV）比ZnS-ZnO高，电荷载流子密度（9.21⋅10¹⁵ cm⁻³）比ZnS-ZnO低，但它表现出更好的光催化效率，这突出了比表面积对所选染料光催化降解的显著影响。ZnS去除有机污染物的效率为88%，而ZnO仅实现43%的去除率，ZnS-ZnO复合材料的去除效率为55%。ZnS的这种卓越效率还得到其更高的比表面积、由于缺陷态导致的光致发光强度降低和可见光谱发射的进一步支持，同时莫特-肖特基分析证实了陷阱态，这些陷阱态在LED光下增强了电荷分离。降解遵循由高效电荷转移和表面相互作用驱动的动态过程。
