Microwave-Assisted Synthesis of CdS-MOF MIL-101 (Fe) Composite: Characterization and Photocatalytic Performance

The present study outlines the synthesis of cadmium sulfide-metal–organic framework (CdS-MOF) MIL-101 (Fe) heterojunctions achieved via fast microwave-assisted reactions. Thus, different CdS-MOF MIL-101 (Fe) ratios were prepared to study their effectiveness as photocatalysts. These compounds were employed in the photocatalytic degradation of methylene blue (MB) under UV and visible irradiation. Structural, morphological, textural, compositional, and optical properties of the synthesized compounds determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV–vis spectroscopy, Raman spectroscopy, and Fourier transform infrared (FTIR) spectroscopy were utilized to characterize the structural, morphological, textural, compositional, and optical properties. Electrochemical impedance spectroscopy (EIS) was also employed to determine photovoltage and photocurrent densities. The resulting valence band offset (V_fb) and band gap energy values were utilized to construct an energy band scheme. Our research revealed that the CdS-MOF MIL-101 (Fe) heterojunction enhances the efficiency of electron–hole pair separation, thereby mitigating charge carrier recombination effects. Moreover, the type I electronic band structure established an efficient reaction mechanism, effectively suppressing the recombination of photogenerated electron–hole pairs. The photocatalytic system demonstrated exceptional behavior, achieving complete MB removal within 30 min of reaction time and exhibiting outstanding stability and reusability after four reaction cycles. These findings highlight the potential of the synthesized compounds in the field of wastewater treatment for organic pollutants, offering a promising alternative to current environmental issues.