Jiajie Xu,Shengye Wang,Changyu Yan,Hafiz Mohammad Adeel Sharif,Bo Yang
Advanced oxidation processes based on sulfate radicals are considered as a promising approach for environmental remediation. In this study, TiO 2 @MIL-101(Fe) is successfully fabricated by a facile impregnation method and is used for sodium persulfate (SPS) activation. TiO 2 @MIL-101@SPS combines the advantages of photocatalysis and SPS activation, which shows high removal efficiency for nitrobenzene and methyl orange. In addition, the effect of multiple factors, including light source, SPS amount and catalyst amount, on nitrobenzene degradation have been investigated. Results show that the nitrobenzene degradation efficiency is up to 66.53 % while that of TOC removal is 32.21 % under 4-h visible light irradiation with 30 mg catalyst and 1.6 mM SPS. Moreover, LC-MS have been carried out to study the route of nitrobenzene degradation. Besides, ESR analysis reveals that both ● SO 4 − and ● OH radicals are generated sustainably under visible light irradiation, and more ● OH radicals can be detected owing to the synergic effect of photocatalysis and SPS activation. Interfacial charge transfer effect provides photoinduced electrons for the Fe 3+ /Fe 2+ cycle in MIL-101(Fe), which boosts the SPS activation process, resulting in high photocatalytic activity.
Developing efficient catalysts for visible light reactions is vital in the field of photocatalysis. This study focuses on the synthesis of novel ternary composites (α-DMACoPc/TiO 2 /MIL-101 (Fe)) by leveraging the excellent adsorption properties of MIL-101 (Fe), the photosensitizing capabilities of phthalocyanine, and the photocatalytic potential of TiO 2 . The nanocomposites’ structural and optical attributes were thoroughly analyzed. X-ray powder diffraction (XRD) was utilized to showcase the crystalline nature of the composites. Furthermore, Fourier transform infrared (FT-IR) studies confirmed the formation of ternary nanocomposites. Optical absorption investigations demonstrated the tuning of the optical band gap from the UV to the visible range. The results indicated that nearly 94% of the organic material was decomposed after 150 min of exposure to simulated sunlight from a xenon lamp. This high efficiency can be attributed to the synergistic interaction among the composites, enhancing light absorption. The composite’s robust stability was evidenced through cyclic tests. Valuable information was provided to advance the design and synthesis of photocatalysts consisting of metal–organic frameworks synergized with semiconductors. Exploring the possibility of mesoporous materials was based on MOFs for photodegradation of organic pollutants. The photocatalytic degradation of organic pollutants by MOFs mesoporous materials was also investigated. The potential of composite materials in the field of dye degradation of industrial waste is confirmed. The good recycling photocatalytic reusability indicates the promising application of this photocatalyst. Graphical Abstract
Construct TiO 2 @MIL-101-Fe S-scheme via impregnation in situ hydrolysis. • Hierarchically distributed TiO 2 maximizes interfacial contact. • Achieves 13.91% cyclohexane conversion and retains high activity after five cycles. • Interfacial fields drive spatial charge separation and preserve redox potentials. • Hierarchical confinement and pore-mouth anchoring enable selective C H activation. The selective photocatalytic oxidation of cyclohexane is a sustainable and environmentally friendly route for KA-oil production, yet it remains limited by low conversion, moderate selectivity, and inefficient charge utilization. This study employed an in-situ TBOT hydrolysis strategy to synthesize a TiO 2 @MIL-101-Fe S-scheme heterojunction with hierarchically distributed TiO 2 nanodomains within the MOF pores, at pore mouths, and on the external surface. This spatially engineered heterostructure enhances photogenerated carrier separation, stabilizes the interface, and improves cyclohexane oxidation efficiency and KA-oil selectivity. The optimized 50 wt% composite material achieved a cyclohexane conversion rate of 14.3%, which was 2.17 times that of the original MIL-101-Fe material. Meanwhile, it still maintained a cyclohexane conversion rate of up to 13.9% and excellent catalytic activity after five cycles. Steady-state and time-resolved photoluminescence, electrochemical impedance, and transient photocurrent measurements reveal accelerated charge separation and prolonged carrier lifetime, enabled by an S-scheme heterojunction with a built-in interfacial electric field. Radical trapping and ESR studies indicate that photogenerated holes and electrons dominate C H activation, with reactive oxygen species contributing synergistically. DFT calculations confirm directional electron transfer and preserved high redox potentials. This work highlights spatially confined S-scheme heterojunctions as a general strategy to enhance photocatalytic efficiency, selectivity, and stability, offering a promising avenue for solar-driven hydrocarbon oxidation. Graphical abstract Download: Download high-res image (215KB) Download: Download full-size image
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