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Thermal evolution of morphological, structural, optical and photocatalytic properties of CuO thin films
摘要： Nanostructured CuO thin films were synthesized by thermal evaporation and annealing. Structural, optical and morphological changes in the CuO film upon annealing and their overall impact on its photocatalytic activity were investigated employing X-ray diffraction, UV–Vis absorption spectroscopy, atomic force microscopy and field emission scanning electron microscopy. Significant modifications in the morphological, optical, structural and photocatalytic behavior of nanostructured CuO thin film were observed upon thermal annealing. Thermal annealing led to the growth of CuO nanoparticles and the average size of CuO nanoparticles increased from 23 nm to 293 nm as the annealing temperature was increased to 600oC. CuO thin film sample annealed at 400 ? C exhibited superior photocatalytic activities over other samples for the degradation of malachite green and methylene blue dyes in 120 and 160 min, respectively. The improved photocatalytic behavior of CuO thin film annealed at 400 ? C is attributed to its narrower band gap, improved utilization of sunlight and enhanced adsorption of dye due to increased surface area arising from formation of CuO nanoparticles and their aggregates at the surface.
关键词： Methylene blue,CuO,Thin film,Photocatalysis,Malachite green
更新于2025-09-23 15:23:52
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Effect of operational parameters on the photocatalytic degradation of Methylene blue dye solution using manganese doped ZnO nanoparticles
摘要： Photocatalytic degradation of aqueous solution of methylene blue dye under UV light illumination was studied by using manganese doped ZnO (Zn1-xMnxO, where x = 0.00, x = 0.02 and x = 0.05) nanoparticles as a photocatalyst. The nanophotocatalysts were synthesized by wet chemical co-precipitation method. The structural, morphological, and optical properties of the photocatalysts were done by X-ray diffraction (XRD), Scanning Electron microscope (SEM), Energy Dispersive X-Ray (EDX), photoluminescence (PL), Fourier Transform Infrared Ray (FTIR) and UV- visible spectroscopic techniques. An improved photocatalytic efficiency of ZnO was observed upon doping with Mn and 2% Mn-doped ZnO exhibited the highest photocatalytic activity among the doped samples. The effect of operating parameters such as amount of catalyst, the initial dye concentration, and initial pH on the rate of dye degradation using 2% Mn-doped ZnO was studied. Under the optimum operation conditions, approximately 99% of dye removal was achieved after 120 min of irradiation.
关键词： Manganese doped ZnO,Photocatalytic activity,Methylene blue dye
更新于2025-09-23 15:23:52
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Ag/Ag2O/BiNbO4 structure for simultaneous photocatalytic degradation of mixed cationic and anionic dyes
摘要： In principle, n-type and p-type semiconductors are respectively responsible for photo-catalytic degradation of cationic dyes (e.g., methylene blue) and anionic dyes (e.g., acid red 1), governed by photoelectrons in the former and photo-holes in the later system. Hence, we present a new strategy: design and fabrication of photocatalytic structures to match the redox potentials of mixed basic/acidic dyes as well as the reactive oxygen species (ROS). For the ?rst time Ag/Ag2O/BiNbO4 structure is (1) designed to match the redox potentials of basic/acidic dyes as well as ROS, (2) fabricated using photoreduction to control the Ag/Ag2O/BiNbO4 interfaces, and (3) able to simultaneously degrade 84% methylene blue dye (MB) in 240 min and 88% acid red 1 (AR) in 25 min under LED light irradiation, corresponding to 7 wt% Ag loading. To the best of our knowledge, this is the ?rst photocatalytic degradation study on mixed basic and acidic dyes using a single catalyst. We also tested the new redox potential matching strategy in mixed basic dyes (MB and rhodamine B (RhB)). As expected our experimental results reproduced well our model predictions: in particular, results support our proposed hydroxyl radical (?OH) mechanism, which is initiated by photo-holes. Therefore, this new design strategy, which consists of matching band structures of the photocatalyst with redox potentials of dyes and ROS, has immediate implications to general photocatalytic applications beyond dye degradation and water-splitting.
关键词： Methylene blue,Nanostructures,Rhodamine B,Photocatalysis,Dye degradation,Acid red,Mixed dyes
更新于2025-09-23 15:23:52
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A triple alkoxo bridged dinuclear cobalt(III) complex mimicking phosphatase and showing ability to degrade organic dye contaminants by photocatalysis
摘要： A dinuclear cobalt(III) complex, [(N3)L1CoIIIL2CoIIIL1] (1), has been synthesized and characterized {H2L1 = 2-((1-hydroxybutan-2-ylimino)methyl)-4-bromophenol and HL2 = 2-amino-1-butanol}. Single crystal X-ray diffraction analysis confirmed its structure. Extended supra-molecular architectures were generated in the complex through weak noncovalent interactions. The energetic features of significant supramolecular interactions have been investigated using DFT calculation and further corroborated with NCI plot index computational tool. The complex has been found to mimic the role of phosphatase enzyme efficiently by transforming 4-nitrophenylphosphate to 4-nitrophenolate at room temperature. The reaction follows Michaelis–Menten enzymatic reaction kinetics with turnover numbers of ~1.4 s-1 in aqueous DMF (98% DMF, v/v) medium. The complex also acts as an efficient photocatalyst for degradation of organic pollutants. Methylene blue (MB), a widely used dye in various industries, was selected as a model pollutant in aqueous media to evaluate the photocatalytic effectiveness of the complex.
关键词： DFT calculation,phosphatase mimicking activity,Photocatalytic degradation of methylene blue (MB),Cobalt(III),Crystal structure
更新于2025-09-23 15:23:52
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Methylene-Blue-Encapsulated Liposomes as Photodynamic Therapy Nano Agents for Breast Cancer Cells
摘要： Methylene blue (MB) is a widely used dye and photodynamic therapy (PDT) agent that can produce reactive oxygen species (ROS) after light exposure, triggering apoptosis. However, it is hard for the dye to penetrate through the cell membrane, leading to poor cellular uptake; thus, drug carriers, which could enhance the cellular uptake, are a suitable solution. In addition, the defective vessels resulting from fast vessel outgrowth leads to an enhanced permeability and retention (EPR) effect, which gives nanoscale drug carriers a promising potential. In this study, we applied poly(12-(methacryloyloxy)dodecyl phosphorylcholine), a zwitterionic polymer-lipid, to self-assemble into liposomes and encapsulate MB (MB-liposome). Its properties of high stability and fast intracellular uptake were confirmed, and the higher in vitro ROS generation ability of MB-liposomes than that of free MB was also verified. For in vivo tests, we examined the toxicity in mice via tail vein injection. With the features found, MB-liposome has the potential of being an effective PDT nano agent for cancer therapy.
关键词： methylene blue,zwitterion,liposome,photodynamic therapy,breast cancer cell
更新于2025-09-23 15:23:52
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Photocatalytic and antibacterial activities of <i>Paeonia emodi</i> mediated silver oxide nanoparticles
摘要： Green synthesis of nanomaterials and its verity of applications have linked chemistry, biotechnology and environmental chemistry. Green process get more attention due to its easy handling and inertness to ecosystem. The selection of green synthesis and silver oxide nanoparticles (Ag2O NPs) are purely based on its nontoxic behavior and promising activates. Eco-friendly process was applied for the synthesis of silver oxide nanoparticles (Ag2O NPs) using Paeonia emodi (P. emodi) fresh leaves extract as reducing agent. The average crystallite size was found to be 38.29 nm, calculated from the FWHM of the diffraction bands of X-rays diffractometer (XRD). The morphological study was made by performing transmission electron microscopy (TEM) and scanning electron microscope (SEM) and the particles size estimated from the micrographs of both techniques are 38.29 and 86.4 nm respectively. The energy dispersive X-ray (EDX) was used to study the purity and percent composition of the Ag2O NPs. The band gap energy (4.02 eV) and surface functional groups was studied by diffuse reflectance spectroscopy (DRS) and fourier transform infrared spectroscopy (FTIR) respectively. The 97.78% methylene blue (MB) was degraded in the presence of Ag2O NPs and UV-Visible light source in 180 min. The antibacterial activity of the Ag2O NPs were tested against Gram-positive (Bacillus subtilis (B. subtilis) and Staphylococcus aureus (S. aureus)) and Gram-negative (Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) bacteria. It was found that the Ag2O NPs have strong growth inhibiting activity against Gram-negative bacteria than Gram-positive bacteria.
关键词： Photocatalytic degradation,Methylene blue,Eco-friendly,Antibacterial Activity,Silver oxide,Leaves extract
更新于2025-09-23 15:23:52
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Microwave Hydrothermal Synthesis of In <sub/>2</sub> O <sub/>3</sub> -ZnO Nanocomposites and Their Enhanced Photoelectrochemical Properties
摘要： Indium oxide (In2O3) doped zinc oxide (ZnO) nanocomposites were successfully synthesized through a facile microwave hydrothermal method. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N2 adsorption–desorption isotherms (BET) and UV-Vis diffuse reflectance spectroscopy. The morphology of In2O3-ZnO composites was observed to be like flowers, and the diameter of particles constituting the porous petal was about 30 nm. The photoelectrocatalytic test results showed that the photoelectrocatalytic methylene blue (MB) degradation efficiency using In2O3-ZnO nanocomposites as photocatalysts under visible light irradiation and a certain voltage could reached above 95.3% after 60 min, much higher than that of In2O3 particles and ZnO particles. The enhanced photoelectrocatalytic activity was attributed to the doping of In2O3 and applied voltage, which beneficially reduced the recombination of electrons and holes in the photoelectrocatalytic process, therefore, it promoted the production of active species (?OH and ?O2-).
关键词： photoelectrochemical properties,visible light irradiation,methylene blue degradation,In2O3-ZnO nanocomposites,microwave hydrothermal synthesis
更新于2025-09-23 15:22:29
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Influence of surfactant on the synthesis of BiOCl/WO3 microcomposites for enhanced adsorption in aqueous solutions
摘要： BiOCl/WO3 microcomposites were synthesized using a one-step hydrothermal route in the presence of a variety of surfactants: polyvinylpyrrolidone (PVP), triethylene glycol (TEG), and Triton X-100 (TX-100). The as-synthesized microcomposites were exploited as efficient adsorbents for removing organic dyes (rhodamine B and methylene blue). Prior to adsorption studies, the structural, functional, and morphological characteristics of these adsorbents were studied using analytical techniques, including XRD, FE-SEM, TEM, and UV-DRS, which revealed the presence of large surface areas. The experimental results show that the PVP-synthesized BiOCl/WO3 microcomposite was significantly more effective as an adsorbent than the microcomposites synthesized using TEG or TX-100. This enhanced adsorption performance is attributable to the larger surface area associated with the developed microstructure of the PVP-stabilized BiOCl/WO3 microcomposite. The BiOCl/WO3 microcomposite synthesized from PVP was subjected to parametric studies involving catalyst dosage, pH, and initial dye concentration. The experimental data were fitted to isotherm models, and the mechanism of adsorption was investigated.
关键词： Rhodamine B,Methylene Blue,BiOCl/WO3 Composite,Adsorption,Surfactant
更新于2025-09-23 15:22:29
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Synthesis of a novel visible light responsive <i>γ</i> -Fe2O3/SiO2/C-TiO2 magnetic nanocomposite for water treatment
摘要： This work investigates the preparation of a magnetically recoverable photocatalytic nanocomposite of maghemite nanoparticles coated with silica and carbon doped titanium dioxide. The novel nanocomposite boasts the advantages of efficient photocatalytic degradation of organic pollutants in water and ease of recovery of the fine particles after water treatment. The photocatalytic nanocomposite was successfully synthesized through a stepwise approach via co-precipitation and sol-gel methods. Characterisation by FTIR, XRD, TEM and EDS substantiated the existence of the intended structure of the nanocomposite and the particles were found to be in the size range of 15–22 nm with a quasi-spherical shape. BET surface area analysis revealed an average surface area of 55.20 m2/g which is higher than that of commercial TiO2 (Degussa P25, 50.00 m2/g) and an average pore diameter of 8.36 nm. A 5 ppm methylene blue solution was degraded with an efficiency of 96.8% after 3 h of solar irradiation, which was 19.7% greater than using the same photo-catalyst under strict UV light irradiation. Photo-catalysis using these nanoparticles was observed to be very effective. The prepared novel visible light active nanocomposite has great potential for incorporation into water treatment systems because it exhibits good stability and magnetism as well as high photocatalytic efficiency.
关键词： methylene blue,titanium dioxide,water treatment,maghemite,photo-catalysis,magnetic nanocomposite
更新于2025-09-23 15:22:29
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Influence of pyrolytic temperature on optoelectronic properties and the energy harvesting applications of high pressure TiO2 thin films
摘要： The present work deals with the development of a novel photocatalyst to decompose most of the organic pollutants. This work provides a strategy for reproducible high-pressure phases of TiO2 at ambient conditions through nebulizer spray pyrolysis (NSP) technique by varying the substrate temperatures of 200–500 °C using titanium (IV) isopropoxide as a titanium precursor. The structural, morphological, optical and electrical properties of the deposited TiO2 thin films were investigated by using X-ray diffraction, field emission scanning electron microscopy, UV–Visible spectroscopy, Hall effect and temperature dependent resistivity measurements, respectively. The structural analysis confirms that the films deposited at higher substrate temperature are crystallized in TiO2–II phase having polycrystalline nature with good crystalline quality and also pressure induced amorphous phases were also observed for the films deposited at lower substrate temperatures. Deposited films have the uniform surface with homogeneity and porous nature which is suitable for enhanced photocatalytic applications. Electrical measurements show that the films are having n-type behavior with appreciable carrier mobility and concentration. The use of high-pressure TiO2-II phase for higher photocatalytic efficiency was demonstrated.
关键词： Photocatalytic,Methylene blue,TiO2-II phase,Spray pyrolysis
更新于2025-09-23 15:22:29