Ag3 PO4 -MIL-53(Fe) Composites with Visible-Light-Enhanced Photocatalytic Activities for Rhodamine B Degradation

Fabrication of MIL-53(Fe)/Ag3PO4 cooperated Photoreduction of Ag0 Particles with outstanding Efficiency on photo-driven H2 Evolution and Pollutant Degradation

The novel heterostructure photocatalyst includes photoreduction of Ag0 loaded MIL-53(Fe)/Ag3PO4 (MFAAx) composites were designed and successfully synthesized via hydrothermal with deposition and photoreduction method. Then the physicochemical and optical properties...

CdS/Ag2S/g-C3N4 ternary composites with superior photocatalytic performance for hydrogen evolution under visible light irradiation

CdS/Ag2S/g-C3N4 ternary composites as photocatalysts with different amounts of Ag2S were successfully synthesized through a simple chemical deposition method. These photocatalysts were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) mapping and X-ray photoelectron spectroscopy (XPS) to obtain the information of the structure and composition. Compared with the pure samples and binary composites, CdS/Ag2S/g-C3N4 ternary composites showed enhanced hydrogen production activities, and the maximum hydrogen production rate of CdS/Ag2S(2%)/CN is about 1020.54 μmol g-1 h-1 in Na2S-Na2SO3 solution. Based on the photoluminescence and electrochemical results, the improved photocatalytic activity could be attributed not only to the synergic effect of ternary components in the composite, but also to the introduction of Ag2S that provided abundant active sites for H2 production. A possible mechanism was investigated in detail.

Synthesis of Metal Organic Frameworks by Ball-Milling

Metal-organic frameworks (MOFs) have been used in adsorption, separation, catalysis, sensing, photo/electro/magnetics, and biomedical fields because of their unique periodic pore structure and excellent properties and have become a hot research topic in recent years. Ball milling is a method of small pollution, short time-consumption, and large-scale synthesis of MOFs. In recent years, many important advances have been made. In this paper, the influencing factors of MOFs synthesized by grinding were reviewed systematically from four aspects: auxiliary additives, metal sources, organic linkers, and reaction specific conditions (such as frequency, reaction time, and mass ratio of ball and raw materials). The prospect for the future development of the synthesis of MOFs by grinding was proposed.

Polyaniline modified MIL-100(Fe) for enhanced photocatalytic Cr(VI) reduction and tetracycline degradation under white light

The Z-scheme MIL-100(Fe)/PANI composite photocatalysts were facilely prepared from MIL-100(Fe) and polyaniline (PANI) by ball-milling, and were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), UV-visible diffuse-reflectance spectrometry (UV-vis DRS), X-ray photoelectron spectroscopy (XPS) and photoluminescence emission spectrometry (PL). The photocatalytic activities of MIL-100(Fe)/PANI composites were investigated via tetracycline degradation and hexavalent chromium reduction in aqueous solution under the irradiation of white light. The results revealed that the MIL-100(Fe)/PANI composite photocatalysts exhibited outstanding photocatalytic activities toward Cr(VI) reduction and tetracycline decomposition. The effects of pH and coexisting ions on the photocatalytic Cr(VI) reduction were investigated. As well, the primary active species were identified via electron spin resonance (ESR) determination. A possible Z-scheme photocatalyst mechanism was proposed and verified. Finally, MIL-100(Fe)/PANI composites demonstrated good reusability and stability in water solution, implying potentially practical applications for real wastewater treatment.

A "bottle-around-ship" like method synthesized yolk-shell Ag3PO4@MIL-53(Fe) Z-scheme photocatalysts for enhanced tetracycline removal

A novel yolk-shell Ag₃PO₄@MIL-53(Fe) Z-scheme photocatalyst was fabricated via a "bottle-around-ship" like method. Experiments on the treatment of tetracycline upon visible light irradiation showed that the as-prepared photocatalyst possessed excellent photocatalytic performance. Experimental results showed that tetracycline removal efficiency of the yolk-shell Ag₃PO₄@MIL-53(Fe) Z-scheme photocatalyst was almost 3 times higher than that of MIL-53(Fe). The enhanced photocatalytic performance of Ag₃PO₄@MIL-53(Fe) nanocomposite could be contributed to its higher surface area, better absorption capability, and greater charge separation efficiency. In addition, the H₂O₂ concentration detection results for Ag₃PO₄ (154 μmol/L) and Ag₃PO₄@MIL-53(Fe) (52 μmol/L) indicated that a big part of generated H₂O₂ on the Ag₃PO₄ core would be quickly decomposed by the MIL-53(Fe) shell and generated more reactive species through the photo-Fenton-like reaction, which is beneficial for the improvement of photocatalytic performance. This is a promising approach to fabricate yolk-shell structure photocatalyst and a different aspect to design multiple semiconductor composites heterojunction for environmental remediation.

Tetrahedral UMOFNs/Ag3PO4 Core-Shell Photocatalysts for Enhanced Photocatalytic Activity under Visible Light

A new visible-light-responsive tetrahedral ultrathin metal-organic framework nanosheet (UMOFNs)/Ag₃PO₄ composite photocatalyst with a core-shell structure was readily synthesized by sonication in an organic solvent. Characterization methods for the photocatalyst included X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, and UV-vis diffuse reflectance spectroscopy. The XRD patterns of the composite photocatalyst before and after visible-light irradiation demonstrated that trace amounts of Ag ions in the composite photocatalyst easily transformed into Ag nanoparticles, which play a role in promoting charge separation at the interface of a heterojunction. The UMOFNs/Ag₃PO₄ composite photocatalyst showed higher photocatalytic activity for the photodegradation of 2-chlorophenol (2-CP) under visible-light irradiation (>420 nm) than Ag₃PO₄. The complete degradation of 2-CP was achieved in 7 min using the tetrahedral UMOFNs/Ag₃PO₄ core-shell photocatalyst, and the apparent reaction rate was approximately 26 times higher than that of pure Ag₃PO₄. Further, a scavenger experiment showed h⁺ and O₂ ^•- were the major reactive species involved in the photocatalytic reaction system. This enhanced photocatalytic activity results from the efficient separation of photoinduced electron-hole pairs and the increase of interface area between Ag₃PO₄, UMOFNs, and the Ag nanoparticles.

A Review on the Synthesis and Characterization of Metal Organic Frameworks for Photocatalytic Water Purification

This review analyzes the preparation and characterization of metal organic frameworks (MOFs) and their application as photocatalysts for water purification. The study begins by highlighting the problem of water scarcity and the different solutions for purification, including photocatalysis with semiconductors, such as MOFs. It also describes the different methodologies that can be used for the synthesis of MOFs, paying attention to the purification and activation steps. The characterization of MOFs and the different approaches that can be followed to learn the photocatalytic processes are also detailed. Finally, the work reviews literature focused on the degradation of contaminants from water using MOF-based photocatalysts under light irradiation.