Rational design of three bifunctional MOFs for photocatalysis degradation and selective adsorption of wastewater organic dyes removal

Controlled solvothermal synthesis of self-assembled SrTiO3 microstructures for expeditious solar-driven photocatalysis dye effluents degradation

In this work, the self-assembled SrTiO3 (STO) microstructures were synthesized via a facile one-step solvothermal method. As the solvothermal temperature increased from 140 °C to 200 °C, the STO changed from a flower-like architecture to finally an irregularly aggregated flake-like morphology. The photocatalytic performance of as-synthesized samples was assessed through the degradation of rhodamine B (RhB) and malachite green (MG) under simulated solar irradiation. The results indicated that the photocatalytic performance of STO samples depended on their morphology, in which the hierarchical flower-like STO synthesized at 160 °C demonstrated the highest photoactivities. The photocatalytic enhancement of STO-160 was benefited from its large surface area and mesoporous configuration, hence facilitating the presence of more reactive species and accelerating the charge separation. Moreover, the real-world practicality of STO-160 photocatalysis was examined via the real printed ink wastewater-containing RhB and MG treatment. The phytotoxicity analyses demonstrated that the photocatalytically treated wastewater increased the germination of mung bean seeds, and the good reusability of synthesized STO-160 in photodegradation reaction also promoted its application in practical scenarios. This work highlights the promising potential of tailored STO microstructures for effective environmental remediation applications.

Synthesis, crystal structure and photocatalytic properties of a three-dimensional copper(II) metal–organic framework based on 1,3,5-tris(2-methylimidazol-1-yl)benzene

A three-dimensional metal–organic framework, namely, poly[[bis(μ3-benzene-1,3,5-tricarboxylato)bis[μ3-1,3,5-tris(2-methylimidazol-1-yl)benzene]tricopper(II)] hexahydrate], {[Cu3(C9H3O6)2(C18H18N6)2]·6H2O} n or {[Cu(BTC)2/3(TMIB)2/3]·2H2O} n , (I) [TMIB is 1,3,5-tris(2-methylimidazol-1-yl)benzene and H3BTC is benzene-1,3,5-tricarboxylic acid], has been synthesized under solvothermal conditions and structurally characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction and thermogravimetric analysis (TGA). Compound (I) features an unusual three-dimensional (3,4)-connected 2-nodal net with {83}4{86}3 topology. Photocatalytic investigations indicate that (I) affords good photocatalytic capabilities in the degradation of methylene blue (MB). Furthermore, the possible photocatalytic mechanism is discussed.

A RGO aerogel/TiO2/MoS2 composite photocatalyst for the removal of organic dyes by the cooperative action of adsorption and photocatalysis

A composite consisting of reduced graphene oxide aerogel/titanium dioxide/molybdenum disulfide (abbreviated as RGO aerogel/TiO₂/MoS₂) was developed for the removal of organic dyes from solution cooperatively by adsorption and photocatalytic degradation mechanisms. The composite was successfully synthesized by stepwise layered assembly integration, including sol-gel and physical vapor deposition (PVD) methods. The resulting multi-component composite material featured a high specific surface area (255.441 m²/g) containing a myriad of negatively charged carboxylate functional groups on the surface of the composite, which enabled the composite material to demonstrate a high removal efficiency of cationic dyes, such as rhodamine B, from solution. In addition, the composite featured optimal optical and photocatalytic properties for facilitating efficient photodegradation of the dye molecules, including a large absorbance in the visible light region and a fast transfer of photogenerated electron-hole pairs. Moreover, electron paramagnetic resonance (EPR) analysis and reactive oxygen species scavenging experiments confirmed that superoxide radicals (O₂^•-), holes (h⁺), and hydroxyl radicals (^•OH) were involved in photocatalytic degradation of the organic dyes.