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Hydration accelerator and photocatalyst of nanotitanium dioxide synthesized via surfactant-assisted method in cement mortar
摘要： To develop TiO2-based cement materials, the effect of TiO2 on the cement hydration and photocatalytic reaction should be investigated. The phase, size and shape of TiO2 are important factors for better understanding its application in cement. TiO2 nanoparticles were synthesized by a surfactant-assisted, reverse micelle method to control phase, size and shape by three selected surfactants namely: sodium dodecyl sulfate (SDS), cetyl trimethylammonium bromide (CTAB) and TritonX-100. The synthesized TiO2 nanoparticles were characterized by XRD, SEM and TEM for observation of phase, size and shape. The modified micro structures of admixed cements with the different synthesized TiO2 nanoparticles incorporated were also examined by SEM. Particularly, the hydration process and photocatalytic reaction of the cement mixture were evaluated by heat flow calorimetry and methylene blue (MB) degradation, respectively. Results showed that anatase-rich and smaller size TiO2 nanoparticles provided accelerated cement hydration and the ability to degrade MB photocatalytically at the surface of admixed-TiO2 cement.
关键词： Surfactant-assisted method,Photocatalytic activity,Hydration,Cement,Titanium dioxide nanoparticle
更新于2025-09-23 15:22:29
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Cu(OH)2 Nanostructures for Dynamic Photodegradation of Methyl Orange under Visible Light
摘要： A new material of Cu(OH)2 nanostructures was prepared using cupric nitrate and sodium hydroxide as raw materials by the chemical precipitation method. The Cu(OH)2 nanostructures were characterized by scanning electron microscope, transmission electron microscopy, infrared spectrometer, and X-ray diffractometer. The results showed that the Cu(OH)2 nanostructures exhibited excellent uniform and dispersion at 40°C. A series of factors was investigated to effect the photocatalytic efficiency of methyl orange (MO), such as the concentration of Cu(OH)2 nanostructures, the reaction time of the Cu(OH)2 nanostructures, the initial concentration of MO, and so on. As a result, the Cu(OH)2 nanostructures exhibited excellent photocatalytic efficiency with the concentration of 20 mg L–1 Cu(OH)2 nanostructures, the initial concentration of MO was 15 mg L–1 and the stirring time was 70 min.
关键词： photocatalytic efficiency,chemical precipitation method,Cu(OH)2 nanostructures
更新于2025-09-23 15:22:29
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The microstructure and optical property of Na-doped ZnO system by sol-gel method
摘要： Pure and Na-doped ZnO (2 at.%, 5 at.% and 10 at.%) films are synthesized by sol-gel method and annealed at 500 °C for 4 h. The as-synthesized nanoparticles are characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) with energy dispersive X-ray spectroscopy (EDS). The samples exhibited hexagonal ZnO lattice structure and another Na2O2 phase was detected in the 5 at.% Na-doped ZnO sample. The calculated average crystalline size increases from 42.0 nm to 43.5 nm when Na content increased from 0 to 10 at.%. FESEM and TEM analysis identifies that the average size of the Na-doped ZnO nanoparticles lies in between 50 nm and they appear in spheroid-like or rod-like shape. The transmittance of the sample was above 80% and the results of photocatalytic activity show that Na-doped ZnO nanoparticles exhibit higher photodegradation activity (about 91%) than pure ZnO nanoparticles under UV irradiation.
关键词： microstructure,Na-doped,photocatalytic activity.,transparent property,ZnO
更新于2025-09-23 15:22:29
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Synthesis and Characterization of ZnO-ZrO <sub/>2</sub> Nanocomposites for Photocatalytic Degradation and Mineralization of Phenol
摘要： ZnO-ZrO2 nanocomposites using zinc (II) acetylacetonate and different ZnO contents (13, 25, 50, and 75% mol) were synthesized through sol-gel method. The synthesis process was strongly related to nanocomposite properties especially on their structural composition. The obtained ZnO-ZrO2 nanomaterials presented tetragonal crystalline structure for zirconia whereas hexagonal one was formed in ZnO. Raman spectroscopy and XRD patterns confirmed the formation of tetragonal zirconia whereas inhibition of monoclinic structure was observed. Addition of ZnO affected the pore size distribution of the composite, and the measured specific surface areas were from 10 m2/g (for pure ZnO) to 46 m2/g (pristine ZrO2). Eg values of ZrO2 were modified by ZnO addition, since calculated values using Kubelka-Munk's function varied from 4.73 to 3.76 eV. The morphology and size of the nanomaterials investigated by electron microscopy showed formation of nanorods for ZnO with sizes ranging from 50 nm to 300 nm while zirconia was formed by smaller particles (less than 50 nm). The main advantage of using the nanocomposite for photocatalytic degradation of phenol was the mineralization degree, since 75ZnO-ZrO2 nanocomposite surpassed mineralization reached by pure ZnO and also inhibited formation of undesirable intermediates.
关键词： sol-gel method,UV-A irradiation,phenol mineralization,photocatalytic degradation,ZnO-ZrO2 nanocomposites
更新于2025-09-23 15:22:29
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Data on the convenient fabrication of carbon doped WO3? ultrathin nanosheets for photocatalytic aerobic oxidation of amines at room temperature
摘要： The oxidation of amines to imines is an important chemical transformation. In this article, we report original data on the synthesis of carbon doped WO3 (cid:1) x ultrathin nanosheets via an acid-assisted one-pot process, which exhibit excellent photocatalytic activity in the aerobic oxidation of amines to corresponding imines under visible light irradiation at room temperature. The composition, microstructure, morphology, photocatalytic activity of the corresponding samples and possible mechanism are included here.
关键词： Ultrathin nano-sheet,Photocatalytic activity,Aerobic oxidation
更新于2025-09-23 15:22:29
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A unique (4,4,5)-connected 3D zinc (II) metal-organic framework for highly efficient photodegradation of Rhodamine B under UV light
摘要： A new zinc (II) metal-organic framework, [Zn3(L)2(nbta)2]n (1) (L = 1,4-bis(benzimidazol-1-yl)-2-butene, H3nbta = 5-nitro-1,2,3-benzenetricarboxylic acid) was hydrothermally synthesized and structural characterized. 1 possesses a unique 3D (4,4,5)-connected network with a Schl?fla symbol of {42.63.8}2{44.62}{47.63}2. Furthermore, the photocatalytic property of 1 for degradation of the Rhodamine B (RhB) was examined under UV irradiation.
关键词： Semi-rigid bis(benzimidazole),Hydrothermal synthesis,Crystal structure,Metal-organic framework,Zinc (II),Photocatalytic degradation
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
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Dispersion of Ag–AgBr particles in activated carbon as a recyclable photocatalyst for adsorption and degradation of pollutants
摘要： The photocatalyst, with high photocatalytic performance and cycling stability in visible light, as well as superior adsorption capability, was highly desired for degradation of organic pollutants in wastewater. In this contribution, the uniform and well-dispersed morphology with cubic Ag–AgBr particles were homogeneously decorated on the porous activated carbon (AC), by a simple solvothermal-photoreduction method, so as to obtain a hybrid photocatalyst with optimized nanostructure. The materials were systematically characterized and further evaluated for degradation of Rhodamine B (RhB) under visible light irradiation. The results indicated that the composite had a high adsorption capacity and photocatalytic properties for the removal of organic compounds, which is attributable to the formation of heterojunctions between Ag0, AgBr and AC. Furthermore, the possible photodegradation mechanism was postulated based on the photoactive radicals test. This study provides new insights into the design and fabrication of advanced visible light photocatalytic materials as well as the potential application in organic pollution cleanup.
关键词： adsorption,photocatalytic properties,Ag–AgBr-AC,photoactive radicals
更新于2025-09-23 15:22:29
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Effect of pH on the Properties of BiVO<sub>4</sub> by Hydrothermal Synthesis Method
摘要： Bismuth vanadate (BiVO4 ) powders were synthesized using Bi(NO3)3.5H2O and NH4VO3 as raw materials, NaOH and HNO3 for pH adjustment. The samples were characterized by X-ray diffraction ( XRD ), scanning electron microscopy (SEM ) and UV-vis diffuse reflectance spectra techniques. The results show that the pH of precursor solution has great effect on the composition and morphology of products. Synthetic product was BiVO4 with two kinds of crystal shape ( monoclinic and tetragonal ) with pH of 3; synthetic product was pure monoclinic phase BiVO4 when the pH is between 5-9. Whereas, V2O5 and Bi2O3 appeared when the pH was 11; synthetic product was a mixture of V2O5 and Bi2O3 with pH of 13, and BiVO4 didn’t exist. The photocatalytic activity was evaluated by the degradation of methylene blue solution. It is shown that the synthetic sample has the best photocatalytic ability with pH of 5. The degradation of methylene blue reaches 84.7% when irradiated for 240 min by high pressure mercury lamp, and the sample synthesized at 13 for pH has strong adsorption capacity and poor photocatalytic ability.
关键词： Bismuth vanadate,Photocatalytic activity,pH value,Hydrothermal synthesis
更新于2025-09-23 15:22:29
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The Effects of the Content of NiO on the Microstructure and Photocatalytic Activity of the NiO/TiO2 Composite Film
摘要： The NiO/TiO2 composite films with the NiO content of 3 %, 5 %, 10 %, 13 %, 15 % and 20 % were prepared by mechanical coating technology and subsequent oxidation process. The composition and microstructure of the films were analyzed by X-ray Diffraction (XRD), scanning electron microscope (SEM), and energy dispersive spectroscopy (EDS). The photocatalytic activity was evaluated and the effects of the content of NiO on microstructure and photocatalytic activity of the films were studied. The results show that NiO particles are dispersed in the Ti coatings, and the NiO concentration in the inner layer of the coatings is higher than in the outer layer. With the addition of NiO in the NiO/Ti coating, the ductility is deteriorated and the thickness is reduced of the NiO/Ti coatings. The films with NiO/TiO2/Ti composite microstructure are obtained by the oxidation of NiO/Ti coatings. Photocatalytic efficiency of the films is obviously enhanced with the help of the p-n junction heterostructure in the NiO/TiO2 films. The optimum content of NiO is about 13 %, and the degradation rate of methyl orange solution reaches the maximum value of 88.44 %.
关键词： mechanical coating technology,NiO content,photocatalytic activity,NiO/TiO2 composite films
更新于2025-09-23 15:22:29