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Preparation and Photocatalytic Performance of Bamboo-Charcoal-Supported Nano-ZnO Composites
摘要： Nano-ZnO/bamboo charcoal composites were prepared by precipitation with bamboo charcoal as support. Nano-ZnO/bamboo charcoal composites were characterized by XRD, SEM and EDS. Photocatalytic degradation processes of methyl orange were studied. The results indicate that the structure of nano-ZnO is of the wurtzite type and the grain size is about 19 – 54 nm. The best preparation temperature for these composites is 500 ℃. The composites have better photocatalytic degradation ability than pure ZnO under UV irradiation. Photocatalytic degradation of methyl orange with the composites obeys first-order kinetics, and the composites can be recycled.
关键词： methyl orange,precipitation,photocatalytic degradation,charcoal,Nano-ZnO
更新于2025-09-10 09:29:36
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Synthesis and characterization of ZnSe and ZnSe:Mn nanosheets and microflowers with high photoactive properties by microwave-assisted method
摘要： Zinc selenide (ZnSe) and manganese-doped zinc selenide (ZnSe:Mn) nanosheet and microflower morphologies were successfully fabricated in only 15-25 minutes in solvothermal reactions under microwave irradiation. In order to compare the effect of microwave heating on the properties of obtained ZnSe nanocrystals, the synthesis under conventional heating was conducted additionally in similar conditions. The obtained nanocrystals were systematically characterized in terms of structural and optical properties using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance UV-Vis spectroscopy (DR UV-Vis), Fourier-transform infrared spectroscopy (FT-IR), photoluminescence spectroscopy (PL), X-ray photoelectron spectroscopy (XPS), Atomic Absorption spectroscopy (AAS) and Brunauer-Emmett-Teller (BET) surface area analysis. ZnSe and ZnSe:Mn nanosheets were synthesized with the length of 300-600 nm, width of 150-400 nm, and thickness about 10-30 nm. The photocatalytic activity of ZnSe and ZnSe:Mn nanocrystals with different morphologies was evaluated by the degradation of methyl orange (MO). The results show that all samples had high coefficient of degradation of MO under ultraviolet irradiation (UV). Manganese-doped ZnSe nanocrystals exhibited superior photocatalytic activity and can offer many wide opportunities and perspectives in the field of photocatalysis and solar energy conversion.
关键词： photoactivity,microflowers,nanosheets,methyl orange,microwave,ZnSe:Mn,ZnSe
更新于2025-09-10 09:29:36
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Synthesis of In2S3/UiO-66 hybrid with enhanced photocatalytic activity towards methyl orange and tetracycline hydrochloride degradation under visible-light irradiation
摘要： In this study, a series of In2S3/UiO-66 (ISU) hybrids have been fabricated through the growth of In2S3 nanoparticles onto the surface of UiO-66 via a facile hydrothermal process. The as-obtained samples have been characterized by PXRD, SEM, TEM, XPS, UV–Vis DRS, PC, PL and BET. The photocatalytic performance is evaluated by methyl orange (MO) and tetracycline hydrochloride (TCH) degradation under visible light irradiation. The results show that the In2S3/UiO-66 hybrids exhibit a higher photocatalytic activity than that of the pure In2S3 and UiO-66. Interestingly, the ISU-40% possesses the highest photodegradation e?ciency towards MO and TCH, which can be attributed to the strong visible light absorption, high speci?c surface area as well as e?ective separation of photo-generated electrons and holes. In addition, the photocatalysis mechanism in MO degradation process is also explored.
关键词： Hybrids,Visible light,In2S3/UiO-66,Methyl orange,Photocatalysis mechanism,Tetracycline hydrochloride
更新于2025-09-10 09:29:36
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ZnO nanospheres based simple hydrothermal route for photocatalytic degradation of azo dye
摘要： This novel work presents a promising application to use Zinc oxide nanospheres as nanocatalysts in photocatalytic degradation of methyl orange dye. The hydrothermal route was utilized in the synthesis process of ZnO nanospheres. The size of the synthesized ZnO nanoparticles is around 200-250 nm diameter. The synthesized nano-oxides were characterized utilizing several instruments such as X-ray diffraction, Brunauer, Emmett, and Teller (BET), and scanning electron microscope (SEM). The resulting nanoparticles are utilized as an efficient tool for degradation of methyl orange (MO) dye under UV radiation. Essential parameters were studied on degradation process involving the initial concentration of MO, pH, stirring the solution, dose of the ZnO nanospheres, the oxygen content of the solution, calcination of the nanomaterials. All activity experiments under UV radiation provide excellent results for the degradation process of MO. Also, the recovery of ZnO nanomaterials was investigated based on the photocatalytic process efficiency. The results show the high possibility of reuse ZnO nanospheres for several photocatalytic processes. Also, the nanocatalysts were applied for a real environmental sample with providing high photocatalytic performance.
关键词： methyl orange,ZnO nanospheres,photocatalytic degradation,hydrothermal method,azo dyes
更新于2025-09-10 09:29:36
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Characterisation and photocatalytic assessment of TiO2 nano-polymorphs: Influence of crystallite size and influence of thermal treatment on paint coatings and dye fading kinetics
摘要： A study on the thermal effects on TiO2 rutile and anatase nano-powders was undertaken and displayed some unusual photoactivity and crystal structure properties. Rutile nano-particles with different crystallite sizes were characterised and the possible effect on activity were investigated. One of the rutile samples appeared to have trace amounts of anatase and was annealed at high temperatures at 1172 K and 1272 K to highlight the thermodynamic stability phenomenon of titania. Parallel to this study, anatase nano-particles were investigated before and after being annealed up to 1022 K. For all the samples used in this work, characterisation was undertaken using micro-Raman microscopy/XRD and Scanning Electron Microscopy (SEM) while photoactivity assessment was made by measuring and monitoring the photodegradation of a mixture of dye methyl-orange (MeO) and nano-powders under UV-light for 3h30 minutes in suspension. The study revealed that rutile nano-powder samples were thermodynamically stable even at very high temperatures and poorly active but with an unusual photoactive feature. Concerning the anatase samples; SEM investigation revealed a questioning size growth as the samples showed a different particle size depending on the temperature of thermal treatment. It revealed that annealing at 672 K seemed to be a key temperature as the particles change from a polyhedral structure to a two-dimensional structure showing a platelet like shape. The photocatalytic studies of the anatase nano-particles showed a very high activity especially before annealing. This highlighted the fact that the anatase phase can subsist at high temperatures such as 1022 K and exhibit a persistence in photoactivity even though it has decreased significantly after 672 K. SEM analysis was in accordance with the photoactivity investigation. Nevertheless, the most interesting feature of the results emanates from the reaction order study and rate constant analysis taken from the kinetic shape of the graph of the degradation of MeO as a function of the irradiation time for the different particle sized rutile nanoparticles. Here a zero-order reaction was determined and as a consequence raised questions about the theory of the mechanism of the activities of titania in terms of surface chemistry, surface area dependence and photoactivity. For example, for the nano-rutiles the sample with a 25 nm crystallite size was the most active and the sample with the smallest crystallite size (15nm) was the least active and yet was found to contain trace levels of nano-anatase. This effect was also substantiated by UV absorption and weathering studies on doped isocyanate-acrylic paint films. UV analysis clearly shows that the absorptivity of the nanoparticles plays a role and correlates with the photoactivity. The 15nm particles have decreased absorptivity in the near UV and hence decreased activity.
关键词： nano-particles,titanium dioxide,crystal size,temperature treatment,anatase,isocyanate-acrylic paint,methyl orange,rutile,photocatalysis
更新于2025-09-09 09:28:46
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How To Correctly Determine the Band Gap Energy of Modified Semiconductor Photocatalysts Based on UV–Vis Spectra
摘要： A misuse of the Tauc plot to determine the band gap energy of semiconductors may lead to erroneous estimates. Particularly large errors can be associated with characterization of modified semiconductors showing a significant absorption of sub-band gap energy photons. Taking the model methyl orange/titanium dioxide system, we address the problem and discuss how to apply the Tauc method correctly.
关键词： band gap energy,UV?Vis spectra,Tauc plot,methyl orange,modified semiconductors,titanium dioxide
更新于2025-09-09 09:28:46
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T?ng h?p v?t li?u CeO2 kích th??c nanomet trên n?n SiO2 và nghiên c?u kh? n?ng quang xúc tác c?a chúng
摘要： The nanomaterials CeO2 with average size of 50 nm on the SiO2 base which performed very high photocatalytic properties were successfully synthesized by the sol-gel combustion method. Starting with freshly precursor, the prepared sample was studied the morphology and characterized by X-ray diffraction, field-emission scanning electron microscopy and Brunauer-Emmetl-Teller method at 77 K. The nanocomposite material contained only 10 % and 20 % of CeO2, but it still presented a significant efficiency on methyl orange degradation under visible light. The CeSi20 which includes 20 % of CeO2 nanoparticles revealed that the photocatalytic capacity with over 97 % of methyl orange was removed after 60 min of the irradiation.
关键词： CeO2,Nanomaterials,photocatalytic,methyl orange degradation
更新于2025-09-09 09:28:46
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Structural, Morphological and Photocatalytic Activity of YMnO <sub/>3</sub> Nanorods
摘要： In this work rod-like YMnO3 were successfully prepared by hydrothermal method. The crystal structure and morphology of prepared samples were characterized by X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The structural information was confirmed from Raman spectrum and the functional group of the sample was studied from FT-IR spectrum. X-ray photoelectron spectroscopy studies confirm the formation and oxidation states of YMnO3. The optical properties of the prepared samples were investigated using UV-vis spectroscopy. The photocatalytic activity of YMnO3 nanorods was evaluated by degradation of methyl orange (MO) under both ultraviolet and visible-light irradiation. The result shows that the YMnO3 nanorods exhibit maximum photocatalytic activity in the degradation of MO.
关键词： YMnO3 Nanorods,Hydrothermal,Methyl Orange,Photocatalytic
更新于2025-09-04 15:30:14
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Iron Oxide Nanoparticles as Potential Scaffold for Photocatalytic and Sensing Applications
摘要： Herein, we report photocatalytic and ?uorescence sensing applications of iron oxide (α-Fe2O3) nanoparticles synthesized by facile low-temperature simple solution process. The synthesized nanoparticles were characterized by several techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) attached with energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), UV-visible spectroscopy and ?uorescence spectroscopy. The detailed analysis revealed that the synthesized nanoparticles were well-crystalline, grown in very high density and possessing rhombohedral α-Fe2O3 crystal structure. The prepared nanoparticles were used as ef?cient scaffold for photocatalytic and sensing applications. The detailed photocatalysis results revealed that in presence of an appropriate amount of α-Fe2O3 nanoparticles as photocatalyst, a signi?cant dye degradation of methyl orange (MO) was observed in 140 min. In addition, the fabricated ?orescence sensor based on α-Fe2O3 nanoparticles exhibited a low detection limit of ～3.33 μM/L towards picric acid. The observed results clearly con?rmed that the synthesized α-Fe2O3 nanoparticles are potential scaffold for photocatalysis and sensing applications.
关键词： Picric Acid,Photocatalysis,Methyl Orange,α-Fe2O3 Nanoparticles
更新于2025-09-04 15:30:14
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Ethiopian natural zeolites for photocatalysis
摘要： The combination of zeolites and photochemistry has recently shown excellent results due to the special structure of the zeolites that helps a better use of the solar energy improving the selectivity of the chemical reactions carried out. There are several reports on the preparation of TiO2 confined nanoparticles in synthetic zeolites. However, very few reports are found on the use of natural zeolites. Zeolites are a vast natural resource in Ethiopia that remains unexploited. Their microporous structure can accommodate a wide variety of cations such as sodium, potassium and magnesium among others. The main objective of our work was to test the potential use of the naturally occurring zeolites, with high content in titanium, as photocatalysts. The samples have been characterized by X-ray diffraction (XRD), chemical analysis (ICP-OES), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (UV-Vis) and photocatalytic activities of the samples were tested in photocatalytic degradation of methyl orange (MO).
关键词： Natural zeolite,Photocatalysis,Methyl orange,Band gap energy,TiO2 loading
更新于2025-09-04 15:30:14