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Insights on the photocatalytic degradation processes supported by TiO2/WO3 systems. The case of ethanol and tetracycline
摘要： TiO2/WO3 composites are widely in the literature as engineered systems for photocatalytic and (photo)electrochemical applications, since the presence of WO3 can promote both visible light absorption and electron transfer phenomena of TiO2. The preparation of these system, depending on the preparation method, can also affect the surface feature with respect to TiO2, modifying adsorption and performance, as well as the reaction mechanisms. Here, TiO2/WO3 composites were prepared by precipitation of WO3 onto the TiO2 surface and characterized in terms of their structural, morphological, optical and surface properties. Raman and IR spectroscopy as well as a marked shift in the isoelectric point support the preferential surface location of WO3. Samples were photocatalytically tested towards the degradation of ethanol and of tetracycline and the adsorption and degradation behaviour were studied, suggesting, in both cases, significant variations of the reaction paths by the addition of WO3.
关键词： Surface properties,Photocatalytic oxidation,Tungsten oxide,Intermediates,Reaction mechanism
更新于2025-09-10 09:29:36
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Furfural-Mediated Synthesis of Mesoporous Ti <sub/>0.5</sub> Sn <sub/>0.5</sub> O <sub/>2</sub> Solid Solution Microspheres for Effective Photocatalytic Removal of As(III)
摘要： The development of highly efficient photocatalyst for oxidizing and further removing toxic As(III) from water environment remains a big challenge. Herein, mesoporous Ti0.5Sn0.5O2 (TSO-0.5) solid solution microspheres are synthesized by a facile solvothermal method and followed by annealing. The mesoporous TSO-0.5 microspheres are systematically characterized in terms of the crystalline phases, morphological, optical, photoelectric and photocatalytic properties using X-ray diffraction, scanning electron microscopy, N2 sorption-desorption, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy, and electrochemical analysis. The characterizations show the TSO-0.5 are of well crystallinity, hierarchical mesoporosity, broad-light responsive capacity, large surface area, and excellent photoelectric features. Under irradiation, the mesoporous TSO-0.5 microspheres exhibit ultrahigh photocatalytic activity for methyl orange degradation (0.537 min-1?m-2, ~8 times that of TiO2) and As(III) removal (up to 98.4%). The photogenerated holes are determined to be the primary active species in the photocatalysis process of MO-degradation and As(III)-oxidation. Based the results, a possible mechanism of photo-induced charge transfer and subsequent reaction processes over the TSO-0.5 is proposed.
关键词： photocatalytic oxidation,As(III) removal,solid solution,mesoporous Ti0.5Sn0.5O2,photocatalyst
更新于2025-09-09 09:28:46
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TiO2-SiO2-PMMA Terpolymer Floating Device for the Photocatalytic Remediation of Water and Gas Phase Pollutants
摘要： Floating photocatalytic devices are highly sought-after as they represent good candidates for practical application in pollutant remediation of large water basins. Here, we present a multilayer floating device for the photocatalytic remediation of contaminants present in water as well as of volatile species close to the water surface. The device was prepared on a novel tailored ter-polymer substrate based on methylmethacrylate, α-methylstyrene and perfluoroctyl methacrylate. The ad hoc synthesized support presents optimal characteristics in terms of buoyancy, transparency, gas permeability, mechanical, UV and thermal stability. The adhesion of the TiO2 top layer was favoured by the adopted casting procedure, followed by a corona pre-treatment and by the deposition of an intermediate SiO2 layer, the latter aimed also at protecting the polymer support from photocatalytic oxidation. The device was characterized by contact angle measurement, UV-vis transmittance and scanning electron microscopy. The final device was tested for the photocatalytic degradation of an emerging water pollutant as well as of vapors of a model volatile organic compound. Relevant activity was observed also under simulated solar irradiation and the device showed good stability and recyclability, prospecting its use for the photocatalytic degradation of pollutants in large water basins.
关键词： titanium dioxide,tetracycline,ethanol,composite,photocatalytic oxidation,polymethylmethacrylate
更新于2025-09-09 09:28:46
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Doping effects on mixed-phase crystalline perovskite AxSr1?xFeO3?δ (A?=?Pr, Sm; 0?≤?x??≤?0.8) nanoparticles and their application for photodegradation of rhodamine B
摘要： A series of doped perovskite AxSr1?xFeO3?δ (A = Pr, Sm; 0 ≤ x ≤ 0.8) nanoparticles were synthesized using a solution combustion method. By doping lanthanide elements, the crystal phase of the perovskite SrFeO3?δ (SFO) changed from cubic to orthorhombic system. Phase transitions and mixed-phase components of prepared catalysts can be successfully controlled only by varying the mole ratio of A-site doping at 800 °C for 5 h. Compared with pure SFO, the Pr/Sm-doped SFO samples exhibited enhanced absorption capability especially in the visible light region. The band gap of Pr/Sm-doped SFO samples was gradually decreased and the BET surface area increased with the increase of the Pr and Sm dopant content. The perovskite AxSr1?xFeO3?δ (A = Pr, Sm; x = 0.6, 0.8) included mixed phases of cubic and orthorhombic crystallinity and exhibited better photocatalytic degradation of rhodamine B (RhB) than single cubic phase. The photodegradation efficiency of RhB was increased with an increasing amount of A-site doping.
关键词： Phase transition,Perovskite,Photocatalytic oxidation,Photodegradation,Mixed phases
更新于2025-09-09 09:28:46
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Acquisition of O2 adsorption isotherms as thorough characterization of nanocrystalline titanium dioxide photocatalysts
摘要： Oxygen plays a crucial role in photocatalytic oxidation as an electron acceptor. Quantification of its adsorption appears to be a useful, although underestimated supplement in characterization of photocatalytic materials. Oxygen adsorption on TiO2 nanopowders was experimentally measured within the pressure interval from 10 to 760 mm Hg using standard equipment. The method of accurate measurement of adsorption capacity of photocatalyst powders was developed in the study. The apparent desorption effect of UV-irradiation on oxygen observed under ambient conditions was attributed to the sample free space measurement error caused by the thermal effect.
关键词： Oxygen adsorption capacity,P25,UV100,Photocatalytic oxidation
更新于2025-09-04 15:30:14