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Structural and photocatalytic properties of co-doped hybrid ZrO2–TiO2 photocatalysts
摘要： In this study, pure TiO2, ZrO2, and hybrid ZrO2–TiO2 photocatalysts were synthesized through solgel process and calcined at three different temperatures. The synthesized photocatalysts were characterized using powder X-ray diffraction (PXRD), field-emission scanning electron microscopy (FESEM), Brunauer–Emmet–Teller (BET), ultraviolet–visible (UV–Vis) spectrometer, and photoluminescence (PL) spectrometer. The PXRD patterns show that the rutile phase of TiO2 was suppressed through co-doping with ZrO2 and produced small crystallite size. The hybrid photocatalysts with small crystallite size recorded the highest surface area of 114.7 m2/g compared to pure TiO2 and ZrO2 photocatalysts as confirmed by BET analysis. Irregular size and shape was observed in the hybrid photocatalysts compared to spherical shape and size in TiO2 and flaky shape in ZrO2 as shown by the FESEM images. The optical properties of the photocatalysts investigated using UV–Vis spectroscopy showed a decrease in band gap energy of pure TiO2 through linear extrapolation from the Tauc’s plot despite the slightly higher band gap energy of the hybrid photocatalysts. However, PL analysis showed that doping of ZrO2 into TiO2 increased the separation efficiency of the electron–hole pairs and enhanced the photocatalytic activity. The phenol degradation of the hybrid ZrO2–TiO2 photocatalysts was higher compared to those of the pure TiO2 and ZrO2.
关键词： Hybrid TiO2–ZrO2 photocatalysts,Solgel,Phenol degradation
更新于2025-11-14 15:25:21
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Acid-treated Fe-doped TiO2 as a high performance photocatalyst used for degradation of phenol under visible light irradiation
摘要： The photocatalytic activity of Fe-doped TiO2 nanoparticles is significantly increased by an acid-treatment process. The photocatalyst nanoparticles were prepared using sol–gel method with 0.5 mol% ratio of Fe:Ti in acidic pH of 3. The nanoparticles were structurally characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy (DRS). It was observed that the photocatalytic activity suffered from an iron oxide contaminating layer deposited on the surface of the nanoparticles. This contamination layer was removed using an HCl acid-treatment process. The photocatalytic activity using 500 mg/L of Fe0.5-TiO2 in a 10 mg/L of phenol solution increased significantly from 33% to 57% (about 73% increase in the performance), within 90 min of reaction time under visible light irradiation. This significant improvement was achieved by removing the iron oxide contamination layer from the surface of the nanoparticles and adjusting pH to mild acidic and basic pHs.
关键词： Kinetics,Iron doping,Phenol degradation,Visible light,Photocatalyst
更新于2025-11-14 15:25:21
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Functionalization of silicon nanowires by iron oxide and copper for degradation of phenol
摘要： Iron oxide (Fe3O4) and copper-functionalized silicon nanowires (SiNWs) from silicon powder mesh < 500 with a spherical structure have been successfully synthesized as a heterogeneous catalyst for the degradation of phenol. This synthesized catalyst was prepared by nanosilicon wire powders. SiNWs have attracted much attention due their potential application in nanoscale devices such as field effect transistors, chemical or biological sensors, battery electrodes and photovoltaics. The SiNW properties were reinforced by functionalization. The synthesis of this catalyst was done by an in situ method for the decoration of SiNWs. Magnetic metal oxide compounds have been chosen not only to accelerate the catalyst recovery but also to improve the time duration of pollution elimination. Also, Cu nanoparticles were added in order to evaluate the catalytic property. In this work, the maximum amount of phenol degradation was obtained near 99.99%. Hybrid surface morphologies were characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, the Brunauer–Emmette–Teller model and high-performance liquid chromatography.
关键词： Mesoporous,Fe3O4–Cu-SiNWs catalyst,Phenol degradation,Sphere
更新于2025-09-23 15:23:52
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Photonic Titanium dioxide film obtained from hard template with chiral nematic structure for environmental application
摘要： In the present work, mesoporous TiO2 with a photonic structure was elaborated using cellulose nanocrystals (CNCs) as a biotemplate by two-step hard template methods. This strategy enables to replicate the chiral nematic (CN) structure of the photonic films (biotemplate) in TiO2 films. A series of iridescent CNCs films with different weight ratios of silica/CNCs composite photonic films were prepared via evaporation induced self-assembly (EISA) method. The films showed iridescent color and tuneable Bragg reflection wavelengths by solely changing the ratio between the silica and the CNCs biotemplate. Polarized optical microscopy (POM) performed on hydride SiO2/CNCs films showed a birefringence and typical fingerprint of chiral nematic structure. This birefringence was also observed for TiO2 films obtained using SiO2 films as a hard template, which suggested the transfer of the chiral nematic structure in TiO2 materials. Afterwards, their optical, morphological and electronic properties were studied by scanning electron microscope (SEM), POM, energy-dispersive X-ray spectroscope (EDX) and time resolved microwave conductivity (TRMC). The photocatalytic activities were evaluated by following the phenol degradation using high performance liquid chromatography (HPLC). The results showed that the structuration of the TiO2 film using a chiral nematic SiO2 film as hard template enhances the photocatalytic performance compared to non-structured mesoporous TiO2.
关键词： hard template,cellulose nanocrystals,iridescent film,evaporation induced self-assembly,light harvesting,phenol degradation,chiral nematic structure
更新于2025-09-23 15:22:29
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Photocatalytic degradation of phenol wastewater over Z-scheme g-C3N4/CNT/BiVO4 heterostructure photocatalyst under solar light irradiation
摘要： A series of carbon nanotubes (CNT) modified g-C3N4/BiVO4 photocatalysts were synthesized via wet-impregnation method and evaluated via degradation of phenol under solar light irradiation. The physicochemical properties of the as-developed photocatalyst were characterized using FTIR, XRD, FESEM, XPS, SAP and DR-UV Vis. The formation of g-C3N4/CNT/BiVO4 photocatalysts resulted in remarkable enhancement in the performance in which almost six times higher degradation rate in comparison to the pristine g-C3N4 and obeyed the pseudo-first-order kinetics and Temkin adsorption model. Congruously, the synergistic interaction between 2 wt. % of CNT and 5 vol. % of H2O2 as an oxidizing agent was capable of removing 80.6 % of phenol within 120 minutes. The profound photodegradation performance monitored was attributed to the better crystallinity structure obtained as shown in XRD and XPS analysis. Furthermore, the intimate contact between the CNT, g-C3N4 and BiVO4 in the heterostructure sample as shown in FESEM micrograph images does help in allowing a smooth electron-hole pair separation and migration, resulting in more available ?OH and ?O2ˉ radicals for photocatalytic degradation activities. The possible Z-scheme reaction mechanism has been proposed and active species trapping experiments have been carried out to find the role of active radical species responsible for the phenol degradation. Additionally, the g-C3N4/CNT/BiVO4 photocatalysts retained excellent stability even after several cycles. Congruently, a mathematical representation for understanding the interaction between CNT loading and H2O2 for photodegradation of phenol using response surface methodology (RSM) was successfully generated.
关键词： phenol degradation,bismuth vanadate,carbon nanotube,wastewater,graphitic carbon nitride,photocatalyst
更新于2025-09-23 15:21:01
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Synergistic effect of surface oxygen vacancies and interfacial charge transfer on Fe(III)/Bi2MoO6 for efficient photocatalysis
摘要： Novel Fe(III) clusters grafted Bi2MoO6 nanosheets with surface oxygen vacancies (denoted as F/BMO-SOVs) heterostructured composite have been firstly fabricated via a reliable calcination process combined with impregnation approach. The surface oxygen vacancies (SOVs) in Bi2MoO6 were formed due to controlled calcination process. The presence of Fe (III) clusters was confirmed by HRTEM, XPS, and UV-Vis DRS. Under visible light irradiation, the optimum molar ratio of 15% F/BMO-SOVs achieved 93.4% degradation efficiency of phenol within 180 min, representing nearly 80 times higher activity than the pure Bi2MoO6, confirmed by both absorption spectrum and TOC measurement. The dramatically enhanced photocatalytic activity is attributed to the synergistic effect between the SOVs, Fe(III) clusters and Bi2MoO6, which not only narrows the band gap, improving the visible light response ability, but also facilitates the direct interfacial charge transfer (IFCT) from the SOVs to the surface Fe(III) clusters, greatly promoting the efficient separation of photogenerated electron-hole pairs. According to the trapping experiments and ESR measurements results, ·O2-, ·OH-, and h+ all participated in the phenol photodegradation process over F/BMO-SOVs. Thus, this work not only provides a synergistic effect between SOVs, Fe(III) clusters and Bi2MoO6 involving an IFCT process, but also proposes an efficient approach to fabricating highly active photocatalysts in environmental remediation and solar fuel synthesis.
关键词： Surface oxygen vacancy,Phenol degradation,Synergistic effect,Interfacial charge transfer,Heterostructured Fe(III)/Bi2MoO6
更新于2025-09-19 17:15:36
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Photocatalytic decontamination of phenol and petrochemical wastewater through ZnO/TiO <sub/>2</sub> decorated on reduced graphene oxide nanocomposite: influential operating factors, mechanism, and electrical energy consumption
摘要： ZnO/TiO2 anchored on a reduced graphene oxide (rGO) ternary nanocomposite heterojunction was synthesized via the multi-step method including hydrothermal, solvothermal and sol–gel methods. XRD, Raman, FESEM, EDX, Dot Mapping EDS, BET, FTIR, UV-VIS, TGA, and EIS techniques were utilized for characterizing as-synthesized catalysts. The XRD and Raman data proved the formation of anatase phase TiO2 and wurtzite phase ZnO in the prepared samples. Further, the UV-Vis spectrum confirmed that the band gap value of ZnO/TiO2 diminished on introduction of graphene oxide. Photocatalytic performance of the fabricated catalysts was investigated by decontamination of phenol in aqueous solutions. The effect of different operational factors such as pH, catalyst dosage, phenol concentration, and light illumination was investigated to find the optimum decontamination conditions. According to the results, complete degradation of phenol was achieved at pH = 4, catalyst dosage of 0.6 g L?1, light intensity of 150 W, and phenol initial concentration of 60 ppm at 160 min under visible light illumination. With the addition of graphene oxide to the composite, a significant increase was detected in the photocatalytic performance due to the higher available surface area and lower electron/hole recombination rate. In addition, the scavenging experiments revealed that the ?OH is responsible for the degradation of phenol during the reaction. The degradation mechanism, economic performance, mineralization, and recyclability were also investigated. Kinetic studies confirmed that photocatalytic degradation process followed the pseudo-first-order kinetic model. A case of real wastewater treatment was used to examine the performance of the catalyst for real case studies.
关键词： Phenol degradation,Nanocomposite,Wastewater treatment,Photocatalysis,ZnO/TiO2,Reduced graphene oxide
更新于2025-09-19 17:15:36
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Efficient Wastewater Remediation Enabled by Self-Assembled Perovskite Oxide Heterostructures with Multiple Reaction Pathways
摘要： Advanced oxidation processes (AOPs) are promising for the removal of retardant organic pollutants in water. However, traditional free-radicals-dominated AOPs are often limited by poor tolerance to water characteristics. Recently, creating nonradical processes has been considered as an effective strategy to overcome this limitation, while the function and mechanism of nonradical processes are still unclear in the important oxides catalytic systems. Herein, the nonradical-dominated peroxymonosulfate (PMS)-based AOPs are triggered on a heterostructural perovskite nanocomposite catalyst (La0.4Sr1.05MnO4?δ), which is constructed from single and Ruddlesden?Popper perovskite phases by a facile self-assembled synthesis method. Noticeably, the phenol degradation rate of the heterostructural nanocomposite oxide is ～2 times that of its individual components. This activity enhancement can be attributed to the abundant active oxygen vacancies, strong affinity to the reactants, and high-electron-transfer efficiency in the unique heterointerface of the nanocomposite. Furthermore, a ternary mechanism is unveiled: contaminants are oxidized not only by the function of radicals and singlet oxygen evoked from the active sites of perovskites but also by the transfer of their electrons to PMS via the beneficial surface of a heterostructral catalyst. This study provides new insights into nonradical-based AOPs derived from hybrid metal oxides in a PMS system.
关键词： Nonradical-based AOPs,Peroxymonosulfate activation,Phenol degradation,Electron-transfer pathways,Perovskite nanocomposites
更新于2025-09-19 17:13:59
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Enhanced photocatalytic activity and stability of AgBr/BiOBr/graphene heterojunction for phenol degradation under visible light
摘要： In this work, we have reported synthesis of AgBr/BiOBr photocatalyst supported on graphene (Gr) using facile precipitation method. AgBr/BiOBr/Gr was characterized using various spectral techniques like FESEM, TEM, XRD, FTIR, XPS, Raman and PL analyses. AgBr/BiOBr/Gr had improved visible light absorption. PL studies indicated the reduction in recombination of photogenerated electron hole pair of AGBr/BiOBr/Gr. AFM analysis con?rmed the thickness of AGBr/BiOBr/Gr was less than 8.0 nm. The higher dispersibility of photocatalyst was ascertained by Tyndall effect. AgBr/BiOBr/Gr photocatalyst was effectively used for the photodegradation of phenol from simulated water. The phenol degradation process was remarkably in?uenced by adsorption process. The concurrent adsorption and photocatalytic was effective for degradation of phenol. The phenol was completely mineralized into CO2 and H2O in 6 h. The degradation process followed pseudo ?rst order kinetics. The results con?rmed that integration of AgBr/BiOBr with graphene caused an increase in photocatalytic activity due to reduced recombination of photogenerated electron hole pair and electron sink behavior of graphene for photogenerated electrons of BiOBr. AgBr/BiOBr/Gr photocatalyst displayed signi?cant stability and recyclability for ten catalytic cycles.
关键词： Enhanced photocatalytic activity,Recyclability,Phenol degradation,Graphene,AgBr/BiOBr,Heterojunction formation
更新于2025-09-11 14:15:04
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STUDY OF AN ANNULAR PHOTOREACTOR WITH TANGENTIAL INLET AND OUTLET.II. THE UV/H <sub/>2</sub> O <sub/>2</sub> REACTIVE FLOW
摘要： The concentration profiles of species involved in the degradation of phenol by an advanced oxidation processes (AOP) are modeled using a CFD tool, in an annular reactor whose fluid dynamics was the object of a previous study. The reactive flow was fully described together with the kinetic model, which encompasses large kinetic constants, such as 101 0 L mol-1 s-1, and the radiation field. Phenol degradation can be simulated b y using relaxation factors of 1012 kg m-3 s-1 at least. The hydroxyl radical concentration profile, depends on the radiation field, performed by the discrete ordinate (DO) and the discrete transfer (DT) methods. Phenol can be completely degraded along the reactor. A centrifugal effect was observed, with higher concentration of degradation products along the inner wall at the reactor outlet.
关键词： Fluence rate,Advanced oxidation process,Computational fluid dynamics,Phenol degradation,Degradation kinetics,Parameter estimation,Modeling
更新于2025-09-10 09:29:36