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Effects of Pt-loading on Formation and Visible Light-Induced Photocatalytic Activity of Bismuth Titanate
摘要： Pt/TiO2-Bi2O3 test catalysts were prepared by impregnating Pt on the sol-gel derived TiO2-Bi2O3 to give these testpieces high photocatalytic activity under visible light irradiation. The optimum Pt support content and TiO2 content were observed in the ranges 0.05-0.3 wt% and 17-28 wt%, respectively in the photocatalytic activity for Methylene Blue (MB) degradation on Pt/TiO2-Bi2O3. Specifically, those 0.1Pt/17TiO2-83Bi2O3, 0.2Pt/23TiO2-77Bi2O3 and 0.3Pt/28TiO2-72Bi2O3 samples showed relatively higher photocatalytic activity for the MB degradation. The results were closely related to (1) the restriction of recombination of the photo-induced electron and hole pairs by Pt, and (2) the presence of bismuth titanate with such high Ti content as built up by Pt.
关键词： Bismuth titanate,Pt-loading,Methylene Blue degradation,Photocatalytic activity,Nucleating agent
更新于2025-09-10 09:29:36
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Applying facilely synthesized CuO/CeO <sub/>2</sub> photocatalyst to accelerate methylene blue degradation in hypersaline wastewater
摘要： Textile and dye effluents have strong color, unstable pH and COD, a lot of inorganic salt, and high biotoxicity. It is difficult and inefficient to remove dyes from high‐saline wastewater by traditional methods. In this study, a simple synthetic CuO/CeO2 photocatalyst is used to achieve high efficiency photodegradation of methylene blue in high salt wastewater. The p‐type CuO/n‐type CeO2 heterojunction photocatalyst is synthesized by a modified hydrothermal‐calcination method. The XRD and XPS reveal the successful synthesis of CuO/CeO2 composite. The SEM and TEM images show that the sample consists of large amounts of well‐dispersed CuO nanosphere loading on the CeO2 layers. DRS exhibits the absorption band (about 510 nm) and the band gap energy (2.43 eV) of the CuO/CeO2 composite. Compared with pure CuO, CeO2, and TiO2 (P25), the prepared CuO/CeO2 can increase the mineralization rate of MB by 18.19%~33.74%. More than 80% of MB can be effectively removed in the wastewater containing 5~80 g/L NaCl with a wide pH value range of 2.11~9.02, and the degradation processes follow the pseudofirst‐order reaction kinetics. Active species trapping experiments confirm that the degradation of methylene blue is mainly attributed to hydroxyl radical; besides, O2?? and hole (h+) also play important roles. Chlorine ions have dual effects in photocatalytic reactions. This work could provide a new approach to construct new heterojunction photocatalysts and a deeper insight for the treatment of hypersaline dye wastewater.
关键词： methylene blue,dye wastewater,hypersaline,UV/H2O2,CuO/CeO2,photocatalysis
更新于2025-09-10 09:29:36
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Synthesis of novel ZnO/carbon xerogel composites: Effect of carbon content and calcination temperature on their structural and photocatalytic properties
摘要： This paper reports the development of new ZnO/carbon xerogel composites (XZn w) for photocatalytic applications. The use of black wattle tannin as a precursor to the carbon xerogel aimed at reducing costs and environmental impacts. The composites were characterized by di?use re?ectance spectroscopy (DRS), BET surface area, scanning electron microscopy (FEG-SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), infrared spectroscopy (IR), and X-ray di?raction (XRD). The photocatalytic performance of the materials was evaluated in the decomposition process of methylene blue, a known toxic pollutant. The impacts of the catalyst dosage and calcination temperature on the photocatalytic process were also examined systematically. The X-ray pro?les of the XZn w evidenced the existence of the hexagonal structure of the zinc oxide (wurtzite) in the composites. The XPS and XRD analyses con?rmed the incorporation of carbon in the zinc oxide crystalline structure. The higher carbon content resulted in a larger surface area. All composites presented the ability to absorb radiation in less energetic wavelengths, contrary to pure zinc oxide that only absorbs radiation of wavelengths below 420 nm. The optimal dosage and calcination temperature were found to be 0.2 g L?1 and 300 °C. All the developed composites displayed signi?cant photocatalytic activities in the decomposition of methylene blue under both visible and solar light. The composites had superior photocatalytic e?ciency under visible light when compared to pure zinc oxide. The XZn 0.5 presented the best degradation e?ciency under visible radiation. All materials presented similar photocatalytic responses under solar light, evidencing the synergy between the carbon xerogel and the zinc oxide. The photocatalytic mechanism was evaluated by trapping experiments to be mainly controlled by the electron vacancies that are generated during the photoexcitation of the composites.
关键词： Zinc oxide,Methylene blue,Carbon xerogel,Tannin,Photocatalysis
更新于2025-09-10 09:29:36
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Synthesis and characterization of Al-Fe-Cu tri-doped TiO <sub/>2</sub> by in-situ hydrothermal for degradation of methylene blue dyes
摘要： Pure TiO2 and a series of Al-Fe-Cu tri-doped TiO2 were synthesized by using in-situ hydrothermal method. The synthesized materials were characterized using X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) and Scanning Electron Microscope (SEM). The photocatalytic activity of the samples was evaluated for degradation of methylene blue (5mgL-1) in aqueous solution under uv-visible light (λ= <420 nm). The XRD pattern showed that all samples exhibited anatase phase after calcined at temperature 500°C with crystallite size in the range of 10.00-13.23 nm. The FTIR spectra showed three important vibrational modes for vOH, δOH and vTiO that were assigned at range 3411.75-3399.27 cm-1, 1626.91-1630.53 cm-1 and 503.30- 530.93 cm-1, respectively. The degradation rate of Al(1mmol)-Fe-Cu tri-doped TiO2 showed the highest photocatalytic degradation with 93% compared to pure TiO2, Al(2 mmol)-Fe-Cu tri-doped TiO2 and Al(3mmol)-Fe-Cu tri-doped TiO2 were calculated as 76%, 85% and 80%, respectively. Hence, it can be seen that, the amount of Al ion-doping have influence on the photocatalytic degradation.
关键词： Al-Fe-Cu tri-doped TiO2,methylene blue,photocatalytic degradation,in-situ hydrothermal
更新于2025-09-10 09:29:36
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Green synthesis of Ag-Mo/CuO nanoparticles using Azadirachta indica leaf extracts to study its solar photocatalytic and antimicrobial activities
摘要： Biogenic synthesis of nanoparticles using natural herb extracts has fascinate huge application owing to its cost effective, non-toxic, eco-friendly and as a flipside path to different physical and chemical actions. CuO (CO), Azadirachta indica extract modified CuO (AzI-CO), silver doped Azadirachta indica extract modified CuO (AzI-ACO), molybdenum doped Azadirachta indica extract modified CuO (AzI-MCO) and silver, molybdenum with Azadirachta indica extract doped CuO (AzI-MACO) nanoparticles have been successfully prepared by simple biosynthesis routes using Azadirachta indica leaf extracts as a green surfactant. The synthesized nanoparticles were characterized by UV–Vis–DRS, XRD, FT-IR, SEM, EDX and TEM techniques. The particle sizes are found to be 25 nm, 19.8 nm, 17.20 nm, 14.57 nm and 11.23 nm for CO, AzI-CO, AzI-ACO, AzI-MCO and AzI-MACO nanoparticles respectively. The solar photocatalytic action of nanoparticles was enumerate by adopting Methylene blue (MB) dye under solar light irradiation. Effects of parameters such as catalyst dosage and initial dye concentration on the degradation of MB dye were investigated. It was observed that the photocatalytic activity in the presence of AzI-MACO (99%) was higher than that of CO (39%), AzI-CO (52%), AzI-ACO (74%), AzI-MCO (88%) nanoparticles, and it follows pseudo first-order kinetics.
关键词： AzI-MACO,Photocatalysis,Azadirachta indica,Antimicrobial studies,Methylene blue
更新于2025-09-10 09:29:36
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Synthesis and Characterization of BaAl2O4 Catalyst and its Photocatalytic Activity Towards Degradation of Methylene Blue Dye
摘要： Hexagonal BaAl2O4 catalyst has been prepared using a gamma-ray irradiation assisted polyacrylamide gel method. The catalysts synthesized at different calcining temperatures were analyzed to insight into their effects on the structural, crystalline, surface morphology, color, optical, fluorescence and photocatalytic properties of the hexagonal BaAl2O4 catalyst. Increasing the calcining temperature has obvious influences on the crystallinity, color, optical properties and the formation of the hexagonal BaAl2O4 catalyst. The optical energy gap (Eg) value of the hexagonal BaAl2O4 catalyst increases with the increasing of calcining temperature. TEM image of the pure hexagonal BaAl2O4 catalyst shows a morphology of flake structure and aggregation. Raman spectroscopy of the pure hexagonal BaAl2O4 catalyst exhibits four luminescent background peaks at 400, 415, 428 and 445 nm mainly due to the oxygen vacancies (VO), Ba vacancies (VBa) and some color centers exists in the BaAl2O4 sample. A comparison of photocatalytic activity among samples for degradation of methylene blue (MB) dye indicates that the pure hexagonal BaAl2O4 catalyst exhibits highest photocatalytic activity under the irradiation of both visible and ultraviolet light. Based on the fluorescence experiment, electrochemical and active species tests, the high photocatalytic activity of the pure hexagonal BaAl2O4 catalyst to be related to hole (h+) and hydroxyl radical (·OH) and also to the defects in the sample.
关键词： BaAl2O4,photocatalytic activity,methylene blue,polyacrylamide gel method,calcining temperature,optical energy gap
更新于2025-09-10 09:29:36
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Synthesis and characterizations of rutile-TiO2 nanoparticles derived from chitin for potential photocatalytic applications
摘要： Single phase rutile Titanium II Oxide (TiO2) nanoparticles were successfully synthesized by wet chemical method using Chitin and TiCl3 as precursor; and the precipitates obtained, dried at 80oC for 10 minutes. The as-synthesized rutile phase TiO2 was characterized by x-ray diffraction, scanning electron microscopy, UV-Vis diffuse reflectance spectroscopy and Fourier transform infrared spectroscopy. The photocatalytic degradation of methylene blue (MB) dye was studied under UV light irradiation using the TiO2 derived from chitin for different load catalyst. The SEM image and Scherrer calculation using FWHM of the XRD peaks confirmed that the as-synthesized TiO2 is spherical, highly crystallinity and nanostructured.
关键词： TiO2 nanoparticles,Chitin,Photocatalysis,wet chemical method,Methylene blue
更新于2025-09-10 09:29:36
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AIP Conference Proceedings [Author(s) Proceedings of the 17th International Conference on Ion Sources - Geneva, Switzerland (15–20 September 2017)] - The photocatalytic degradation of methylene blue using graphene oxide (GO)/ZnO nanodrums
摘要： The nanocomposites of GO/ZnO nanodrums were successfully synthesized and applied for photocatalytic degradation of methylene blue. GO was synthesized by Hummer method and ZnO nanodrums was synthesized by hydrothermal method. Characterization of GO and ZnO nanodrums was performed using XRD (X-Ray Diffraction), SEM (Scanning Electron Microscopy), UV-Vis spectrophotometer, and FTIR (Fourier Transform Infra-Red). GO/ZnO nanodrums was mixed of GO and ZnO with various composition. The variation of GO/ZnO nanodrums was 1: 0; 1: 1, and 1: 2 (w/w) in distilled water. This composite was then carried out in photocatalyst degradation process of Methylene Blue. XRD of GO showed that graphene oxide has been formed with good crystallinity. The obtained morphology showed that regular arranged sheets/layer has been formed. The peak of GO showed in UV region and from the FTIR data indicated absorption at 3500 cm-1 which is O-H uptake. In graphene oxide, OH groups act in photocatalytic activity. ZnO nanodrums showed 3 dominant peak in the 2θ= 30-40°. This showed that ZnO had high crystallinity with crystallite size was 43.46 nm. The morphology of ZnO was nanodrums and it had peak UV at 369 nm. The result of the composite GO/ZnO nanodrums was applied in the photocatalytic of methylene blue with several variations. Photodegradation of methylene blue showed the increasing photocatalytic degradation by GO addition. GO/ZnO nanodrums could degrade methylene blue reach 94.05% during 1 hours contact time and under 254 nm of UV radiation.
关键词： ZnO nanodrums,Graphene Oxide,methylene blue,photocatalytic degradation
更新于2025-09-10 09:29:36
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Photocatalytic activity of Ag<sub>3</sub>PO<sub>4</sub> prepared using a mist-solution precipitation method
摘要： Ag3PO4 was synthesized using a mist-solution precipitation method. The Ag+ mist generated by ultrasonic piezoelectric disk transferred in a flow of air to react with a solution of Na2HPO4. When the reaction temperature was increased from 30 °C to 85 °C, the particle size and crystallinity of the obtained Ag3PO4 also increased. The Ag3PO4 prepared at 70 °C showed the best degradation rate of 0.117 min-1 under light emitting diode irradiation. The photocatalytic degradation of methylene blue was studied as a function of the photocatalyst loading, the initial MB concentration, the light intensity, and the initial pH. The results of the recycling test showed that the Ag3PO4 prepared at high reaction temperature had relatively better resistance to photocorrosion than the Ag3PO4 prepared at low reaction temperature.
关键词： photocatalytic degradation,mist-solution precipitation,methylene blue,Ag3PO4
更新于2025-09-09 09:28:46
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Transmission electron microscopy revealing the mechanism of action of photodynamic therapy on Trichomonas vaginalis
摘要： Trichomonas vaginalis is an amitochondrial parasite that causes human trichomoniasis. Despite metronidazole effectiveness, resistant cases are becoming more frequent. This scenario reveals the need to develop new therapeutic options. Photodynamic Therapy (PDT) is an experimental treatment that involves the activation of photosensitive substances and the generation of cytotoxic oxygen species and free radicals to promote the selective destruction of target tissues. In previous work, we identified an excellent in vitro PDT activity using methylene blue and light emitting diode against metronidazole sensitive and resistant strains of T. vaginalis. Here, we evaluated the efficacy of PDT in vivo and its high trichomonicidal activity was assessed through transmission electron microscopy. Female Balb/c mice were infected intravaginally with T. vaginalis trophozoites. On the third day of infection, methylene blue was introduced into the vaginal canal, which then received 68.1 J / cm2 of radiation for 35.6 sec. Twenty-four hours after treatment the vaginal canal of the animals was scraped and the samples processed by the immunocytochemistry technique. Besides that, in vitro photodynamic treatment was performed and T. vaginalis trophozoites were processed by transmission electron microscopy. PDT significantly reduced infection in animals treated, compared to control groups, being as efficient as metronidazole. Morphological changes observed have suggested that PDT activity on T. vaginalis was due to necrosis. These results, added to the high trichomonicidal activity of PDT confirm its feasibility for trichomoniasis treatment.
关键词： Methylene Blue,Transmission Electron Microscopy,Trichomonas vaginalis,Photodynamic Therapy,Treatment
更新于2025-09-09 09:28:46