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<p>Semiconductors are widely used as photocatalysts due to their versatility in degrading both organic and inorganic molecules upon exposure to light. However, intrinsic phenomena such as charge carrier recombination as well as inadequate bandgap pose challenges to their widespread application. In this study, ZnO-SrCO<sub>3</sub> nanocomposites were fabricated by implementing the microwave-heated assisted polyol process using a water-ethylene glycol mixture as a solvent and then microwaved for only 6&#xa0;min. The composite was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis with differential scanning calorimetry (TGA/DSC). The XRD results revealed the simultaneous co-existence of ZnO and SrCO<sub>3</sub> phases, indicating the formation of a composite. In addition, the XRD analysis indicated crystallite sizes of 12&#xa0;nm for ZnO and 17&#xa0;nm for SrCO<sub>3</sub> with hexagonal and orthorhombic crystal structures, respectively. FESEM results showed that ZnO forms clusters, while SrCO<sub>3</sub> appears as three-dimensional nanorods. The FTIR observations confirm the existence of CO<sub>3</sub><sup>2−</sup> species, which support the successful obtention of the SrCO<sub>3</sub> phase. Photodegradation test indicated that the developed photocatalysts exhibit activity for methylene blue (MB) under both visible and ultraviolet (UV) simulated light. The degradation tests showed an efficiency of 87.5% under visible light in 120&#xa0;min, while UV light achieved a higher efficiency of 93.2% in just 90&#xa0;min for a 15 ppm MB solution. The photocatalytic rate constant for the pseudo-first-order kinetic model was 0.018&#xa0;min<sup>−1</sup> for visible light and 0.034&#xa0;min<sup>−1</sup> for UV light. Moreover, the reusability test revealed that the composite retains excellent performance, exhibiting just a 15.3% decline in efficiency after four reuse cycles under a high methylene MB concentration of 30 ppm. Thus, the findings indicate that the adopted synthesis method may be pivotal in developing ZnO-SrCO<sub>3</sub> semiconductor-based composites with tailored crystal structures that are effective for dye degradation.</p>

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Ultrafast microwave preparation of ZnO-SrCO3 nanocomposites for the methylene blue dye degradation under ultraviolet and visible light

  • 期刊论文

  • 发表日期：

    2025年7月16日

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  • G. E. Hernández-Villegas,
  • W. J. Pech-Rodríguez,
  • G. G. Suarez-Velázquez,
  • C. A. Calles-Arriaga

摘要

Semiconductors are widely used as photocatalysts due to their versatility in degrading both organic and inorganic molecules upon exposure to light. However, intrinsic phenomena such as charge carrier recombination as well as inadequate bandgap pose challenges to their widespread application. In this study, ZnO-SrCO3 nanocomposites were fabricated by implementing the microwave-heated assisted polyol process using a water-ethylene glycol mixture as a solvent and then microwaved for only 6 min. The composite was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis with differential scanning calorimetry (TGA/DSC). The XRD results revealed the simultaneous co-existence of ZnO and SrCO3 phases, indicating the formation of a composite. In addition, the XRD analysis indicated crystallite sizes of 12 nm for ZnO and 17 nm for SrCO3 with hexagonal and orthorhombic crystal structures, respectively. FESEM results showed that ZnO forms clusters, while SrCO3 appears as three-dimensional nanorods. The FTIR observations confirm the existence of CO32− species, which support the successful obtention of the SrCO3 phase. Photodegradation test indicated that the developed photocatalysts exhibit activity for methylene blue (MB) under both visible and ultraviolet (UV) simulated light. The degradation tests showed an efficiency of 87.5% under visible light in 120 min, while UV light achieved a higher efficiency of 93.2% in just 90 min for a 15 ppm MB solution. The photocatalytic rate constant for the pseudo-first-order kinetic model was 0.018 min−1 for visible light and 0.034 min−1 for UV light. Moreover, the reusability test revealed that the composite retains excellent performance, exhibiting just a 15.3% decline in efficiency after four reuse cycles under a high methylene MB concentration of 30 ppm. Thus, the findings indicate that the adopted synthesis method may be pivotal in developing ZnO-SrCO3 semiconductor-based composites with tailored crystal structures that are effective for dye degradation.