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Photocatalytic degradation of sulfur black dye over Ce-TiO2 under UV irradiation: removal efficiency and identification of degraded species
摘要： TiO2 and Ce-TiO2 photocatalysts have been synthesized via sol–gel method and characterized by various techniques. Cerium incorporation maintains anatase phase formation, reduces the band gap energy, and inhibits the electron–hole recombination leading to a better photocatalytic response. Photocatalytic activities are explored on the degradation of sulfur black dye under UV light in the presence of H2O2. Photocatalytic reaction parameters have been assessed. Indeed, sulfur black dye color removal reached 92% at the optimal conditions in presence of 1% Ce-TiO2 catalyst. Identification of degradation products of sulfur black dye was achieved by LC/MS.
关键词： Ce-doped TiO2,Photodegradation,LC/MS analysis,Sulfur black dye
更新于2025-09-23 15:22:29
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Loading of alkaline hydroxide nanoparticles on the surface of Fe2O3 for the promotion of photocatalytic activity
摘要： This study focused on surface modification of iron oxide (Fe2O3) by loading alkaline oxide nanoparticles to investigate the effect of surface interactions on photocatalytic activity of this material. Fe2O3 was loaded by NaOH, KOH, and CsOH, with 0.05, 0.1, 0.4, and 1 wt% by impregnation method. The photocatalytic evaluation was carried out in a gas phase for degradation of Iso-Propyl alcohol (IPA) to acetone. The prepared samples were characterized by X-ray diffraction, UV-Visible diffuse reflectance spectroscopy, and scanning electron microscopy SEM. The photocatalytic evaluation resulted the photoactivity of Fe2O3 increases to an optimum extent by loading of alkaline hydroxides on the surface. The enhancement of photoactivity of Fe2O3 after loading can be attributed to the surface chemical reactions and transfer of photogenerated electrons from the conduction band of Fe2O3 to alkaline nanoparticles. Also, multi-electron oxygen reduction is another way supposed to facilitate the photocatalytic reaction.
关键词： CsOH,Photocatalysis,NaOH,Photodegradation,Impregnation,KOH,Fe2O3
更新于2025-09-23 15:22:29
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Preparation of La doped ZnO ceramic nanostructures by electrospinning–calcination method: Effect of La3+ doping on optical and photocatalytic properties
摘要： Ceramic nanostructures of ZnO doped with La3+ ions (0.02%, 1%, 2% and 4%) were prepared by electrospinning-calcination method. Polyvinylpyrrolidone (PVP) was used as an additional polymer to promote the electrospinning. And, the intermediate electrospun products were processed thermically at 700 °C for 3 h. The produced materials were characterized morphologically and structurally by using scanning/transmission electron microscopy (SEM/TEM) and X-ray diffraction (XRD). The XRD patterns showed the successful incorporation of La ions in the hexagonal wurtzite structure of ZnO. Optical band gaps of these ceramic nanostructures were estimated from reflectance data using Kubelka-Munk theory and were found to vary from 2.589 to 2.889 eV, depending on La3+ doping concentration. Photoluminescence spectra of undoped/doped ZnO with different contents of La3+ ion were investigated. The decay curves for the La3+ ion doped ZnO nanostructures were measured and the average lifetime was found to increase from 2.69 to 2.80 ns when La3+ content increased from 0 to 4%. The photocatalytic activity of doped products (ZnO:La) was investigated by using Congo-Red dye as a probe molecule for degradation under UV-light. Maximal color removal efficiency (97.63%) was observed experimentally for ZnO doped with 2% La3+ in dosage of 0.283 g/L. Finally, the recovered catalyst was thermally activated at 700 °C (1 h) and then successfully reused for the dye photodegradation.
关键词： La-doped ZnO nanostructures,Photodegradation kinetics,Photocatalyst,Optical properties,Electrospinning
更新于2025-09-23 15:22:29
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Sono-solvothermal fabrication of ball-flowerlike Bi2O7Sn2-Bi7O9I3 nanophotocatalyst with efficient solar-light-driven activity for degradation of antibiotic tetracycline
摘要： A novel Bi2O7Sn2-Bi7O9I3 nano-heterostructure photocatalyst with the different weighted percentages and as I-type heterojunction, which acts as pseudo-type II heterojunction, were successfully synthesized using sono-solvothermal manner for the first time. The coupled nanophotocatalysts with various weighted contents of Bi2O7Sn2 and Bi7O9I3 were characterized with XRD, FESEM, EDX, DRS, BET-BJH and pHpzc analyses. Meanwhile, the photocatalytic activity of various nanocomposites was evaluated in the remediation of the antibiotic tetracycline after 90 min irradiation. Results depicted that the ball-flowerlike Bi2O7Sn2(60)-Bi7O9I3(40) nanophotocatalyst, as a mesoporous structure and the type I-heterostructure which appears as an efficient solar-light-driven pseudo-type II heterojunction, represented the best photocatalytic efficiency. This is addressed by the suitable absorption of light range, high separation of charge carriers and its large surface area which provide more active sites for absorption of tetracycline molecules. Furthermore, to elucidate the how the influence of various parameters on the photodegradation efficiency, the different experiments were conducted over Bi2O7Sn2(60)-Bi7O9I3(40). The high activity was obtained in the medium with pH = 6, catalyst loading = 1 g/L and tetracycline concentration = 35 mg/L. Moreover, the capable of reusability and reaction mechanism of improved photodegradation on mentioned photocatalyst were investigated.
关键词： Sono-solvothermal,Water treatment,Antibiotic tetracycline,Photodegradation,Bi2O7Sn2-Bi7O9I3 nanophotocatalyst
更新于2025-09-23 15:22:29
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Effect of Transition Metal Oxide Doping (Cr, Co, V) in the Photocatalytic Activity of TiO2 for Congo Red Degradation under Visible Light
摘要： Comparative study of Cr, Co or V-doped TiO2 was carried out. The photocatalysts were synthesized via sol-gel method. The results indicated that the dopants of Cr, Co, and V induced anatase to rutile phase transition of TiO2 at different dopant amounts of 1, 4, 2 mol%, respectively. Besides that, the existence of dopant extended the absorption wavelength of TiO2 to visible light region, thus making it a visible-driven photocatalyst. The doped transition metal exhibited different oxidation states on the TiO2 surface. The prepared photocatalysts were tested over photodegradation of Congo Red. Amongst all, Cr-doped TiO2 (3 mol%) was the best photocatalyst attributed to the presence of 45% rutile phase, reduced band gap energy of 2.30 eV and formation of Cr6+, which acted as an electron scavenger to delay the hole-electron recombination.
关键词： photodegradation,congo red,transition metal oxide,Titania
更新于2025-09-23 15:22:29
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In-situ ion exchange synthesis of Ag2S/AgVO3 graphene aerogels for enhancing photocatalytic antifouling efficiency
摘要： Efficient charge separation and cycle stability are critical for water purification by semiconductor photocatalyst. Herein, novel Ag2S/AgVO3 graphene aerogels (Ag2S/AgVO3@GAs) were synthesized via an in-situ ion exchange method. The series of characterization results verified that the Ag2S/AgVO3@GAs synergistically integrate the excellent properties of the Ag2S and AgVO3 into the macroscopic porous graphene aerogel. Furthermore, owing to the chelation of chitosan (CS) for AgVO3 and the ion exchange between well-dispersed AgVO3 and Na2S, the Ag2S can in situ grow on AgVO3, which prevents Ag2S and AgVO3 agglomeration/shedding in the photocatalytic reaction and contributes to the enhanced photocatalytic activity and cyclic stability. Benefiting from the unique structure, the Ag2S/AgVO3@GAs with excellent stability displayed the outstanding photodegradation efficiency for methyl orange (97% removal rate in 40 min) and disinfection activity for Escherichia coli (100% antibacterial efficiency in 36 min).
关键词： Photodegradation,Disinfection,Charge transfer,Three-dimensional graphene aerogel,Heterojunction
更新于2025-09-23 15:22:29
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A critical review on visible-light-response CeO2-based photocatalysts with enhanced photooxidation of organic pollutants
摘要： Organic pollutants’ treatment in wastewater has attracted extensive attention due to its degradation-resistance and potentially hazardous to human health. Some organic matters such as persistent organic pollutants (POPs) could exist in environment and resist to decomposition, which may cause chronic intoxication or even cancers. Because photocatalytic technique is efficient, nontoxic, and cost-effective to degrade organic pollutants, some semiconductors including TiO2 and ZnO as photocatalysts have aroused wide public concern. CeO2 has been reported as an efficient photocatalyst in contrast to TiO2 owing to its high oxygen storage, eco-friendly properties and photostability. But inefficient utilization of solar energy due to its intrinsic wide bandgap restrains its further application in real environmental pollutant treatment. In order to improve photocatalytic performances of CeO2, some modifications have been developed such as doping ions, coupling with semiconductor and construction of CeO2-based solid-solution. The purpose of this review is to introduce these techniques, reveals its fundamental mechanisms and the recent researches about photodegradation of organic pollutants in wastewater over CeO2-based photocatalysts. Besides, this review will evaluate the photocatalytic performance for organic pollutants and outlook the challenges and prospects in the future.
关键词： Modification,CeO2,Visible-light-response,Photodegradation,Organic pollutants
更新于2025-09-23 15:21:21
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Plasmon-Enhanced Photodegradation of Ionic Liquids with Ag Nanocubes/ZnO Microsphere Composites
摘要： Ionic liquids (ILs) have been a hot topic in the past decades because of their unique properties and promising applications in various areas. However, the toxicity of ILs and their possible risk to the environment and aquatic organisms have also been confirmed. Therefore, it is imperative to seek an efficient way to remove or degrade ILs in the polluted aqueous system. In this work, Ag nanocubes/ZnO microspheres composites have been designed, prepared, and used for the photocatalytic degradation of eight commonly used imidazolium-based ILs in aqueous solution. It is found that ZnO semiconductor photocatalyst with an Ag content of 1.12 at. % can degrade 90% of all these ILs within 7 h. The structural characterization, photoluminescence analysis, and discrete dipole approximation calculations showed that the loading of Ag nanocubes onto ZnO microspheres significantly improves the performance of ZnO for the IL degradation through hot electron transfer and electrical field enhancement. In addition, the formed intermediates in the degradation process of [C4 mim]Cl have been detected by gas chromatography?mass spectroscopy. A possible degradation mechanism is proposed and compared with those previously reported in the chemical degradation.
关键词： Photodegradation,Ionic liquids,Plasmon-enhanced,ZnO microspheres,Ag nanocubes
更新于2025-09-23 15:21:21
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Effect of metal doped and co-doped TiO2 photocatalysts oriented to degrade indoor/outdoor pollutants for air quality improvement. A kinetic and product study using acetaldehyde as probe molecule
摘要： This study demonstrates the photocatalytic decomposition of an indoor air pollutant, acetaldehyde (CH3CHO), over 0.04 mol% metal-doped TiO2 (Mn-, Co- and Mn/Co-) nanoparticles activated by ultraviolet and visible irradiation. The photocatalytic activity, the photodegradation kinetics, and the ?nal product analysis were examined using a Static Photochemical Reactor coupled with a FTIR spectrophotometer. CH3CHO undergoes ef?cient decomposition over all photocatalysts under UV irradiation in the presence of one atmosphere N2 or synthetic air (SA). Metal doping causes substantial in?uence to photocatalysis by altering the amount of electron/hole pairs generated and/or the electron/hole recombination rates. Simulating the experimental results with pseudo-?rst order kinetics the corresponding degradation rate coe?cients were determined for each photocatalyst under UV irradiation and SA environment: kd UV(Mn-TiO2) = (1.9 ± 0.2)×10 ?1 h ?1, kd UV(Co-TiO2) = (2.8 ± 0.3)×10 ?1 h ?1, and kd UV(Mn/Co-TiO2) = (6.0 ± 0.7)×10 ?1 h ?1. These degradation kinetics under UV light irradiation are signi?cantly faster than undoped TiO2 revealing that the transition metal doping of TiO2 nanomaterials boosts the photocatalytic degradation of organic pollutants. Substantial decomposition of CH3CHO was achieved under visible light in the presence of oxygen over Mn-TiO2 with kd Vis(SA) = (0.44 ± 0.04)×10 ?1 h ?1 while for other samples no visible light photocatalysis was observed. CO2, CO, and H2O were the main oxidation products, with CO2 yields almost 100% under UV excitation, and CO yields up to 20% under UV and < 1% under visible excitation. Our experimental results suggest that Mn-TiO2 (0.04 mol%) nanoparticles may be considered as a potentially safe photocatalyst to remove acetaldehyde particularly from indoor atmospheric environments under visible irradiation, without yielding signi?cant toxic by-products. Other possible atmospheric implications are also discussed in the paper.
关键词： Metal-doped TiO2,Visible-ultraviolet photocatalysis,Photodegradation kinetics,Acetaldehyde,Indoor air pollution
更新于2025-09-23 15:21:21
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Spectroscopy for contemporary art: Discovering the effect of synthetic organic pigments on UVB degradation of acrylic binder
摘要： The influence of Synthetic Organic Pigments in the degradation of Acrylem AC 33, a waterborne acrylic binder, after UVB-artificial exposure was furtherly investigated, extending the study to other pigments classes (anthraquinones, phthalocyanines, diketo-pyrrolo-pyrroles) in addition to previously studied azo-pigments. Together with Fourier Transform Infrared, both in Attenuated Reflectance and Transmission mode, and Nuclear Magnetic Resonance spectroscopies, Raman spectroscopy was also used to observe ageing processes that pigments are subjected to. Specific effects, relative to the presence of different pigments, have been observed also in this study; moreover, Raman spectroscopy highlighted photoinduced effects on some pigments, which could result useful in Cultural Heritage diagnostics, especially for street artworks.
关键词： diketo-pyrrolo-pyrrole,photodegradation,phthalocyanine,acrylic,anthraquinone
更新于2025-09-23 15:21:21