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Preparation of TiO <sub/>2</sub> nanoparticles by hydrolysis of TiCl <sub/>4</sub> using water and glycerol solvent system
摘要： The anatase phase TiO2 nanoparticles (NPs) were synthesized by precipitation method using TCl4 as a precursor in a new reaction medium containing water and glycerol. The as-synthesized photocatalysts were characterized by Raman spectroscopy, Fourier Transform Infra-red Spectroscopy (FT-IR), UV-Visible spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). The Raman spectra indicate the formation of crystalline anatase phase TiO2 NPs after calcination at 300 and 4000C. TiO2 NPs formation was confirmed by observing the major characteristic, FT-IR vibration bands of Ti-O network. The band gap calculated from UV-Vis DRS spectra ranged from 3.02-3.28 eV. FESEM images exhibit spherical shape TiO2 NPs in the form of nano-clusters with crystallite sizes ranged from 9.50-26.14 nm. FESEM images show that as the calcination temperature increases, the sizes of the TiO2 NPs also increase. The inclusion of glycerol promotes the formation of smaller particles and lowers the band gap of TiO2 NPs.
关键词： precipitation method,TiO2 nanoparticles,hydrolysis,anatase phase,Raman spectroscopy,FESEM,UV-Visible spectroscopy,water and glycerol solvent system,FT-IR,TiCl4
更新于2025-09-09 09:28:46
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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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An efficient fabrication of ZnO–carbon nanocomposites with enhanced photocatalytic activity and superior photostability
摘要： Synthesis of carbon nanoparticles (CNPs) and their composite with ZnO has proposed for the first time by combustion of camphor and chemical precipitation method. TEM image shows the surface of ZnO covered by tiny CNPs and acts as structure directing agent that transforms ZnO nanorods to uniform spherical ZnO. CNPs play a vital role to improve the photocatalytic activity and photostability of ZnO up to five runs due to impeding the photo-corrosion of ZnO. Enhance in the photocatalytic activity of ZnO–carbon nanocomposite could be attributed to the excellent dye adsorption capacity, direct photooxidation of dye and suppression of photoinduced electron–hole recombination. The presence of CNPs in nanocomposite served as the main role in accepting the photogenerated electrons due to electronic interaction between ZnO and CNPs. The cytotoxicity studies of meristematic root tip cells of Allium cepa reveals that photocatalytically degraded products were less toxic.
关键词： Photostability,ZnO–carbon nanocomposites,Photocatalytic activity,Chemical precipitation method,Camphor combustion
更新于2025-09-09 09:28:46
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Photo-electrochemical properties of p-type AgCoO2 prepared by low temperature method
摘要： AgCoO2 prepared by co-precipitation at low temperature (~ 80 °C) is characterized by physical and photo-electrochemical techniques. The X-ray diffraction shows broad peaks with a particle size of ~ 20 nm and a specific surface area of ～ 28 m2 g?1. The forbidden band (1.33 eV) is due to Ag+: d → d transition, further transition at 4.50 eV is assigned to the charge transfer. The transport properties, measured up to 650 K, indicate intrinsic conductivity: σ = σo exp{? 0.24 eV/kT (Ω-cm)?1}, supporting a phonon assisted conduction mechanism. An exchange current density of 1.27 mA cm?2 in Na2SO4 (0.1 M) solution is consistent with the electrochemical stability up to 0.8 VSCE. The capacitance measurement (C?2 - E) indicates p type conduction, with a flat band potential (Efb) of 0.26 VSCE and a holes density (NA) of 7.38 × 1019 cm?3 due to the oxygen insertion in the layered lattice. The electrochemical impedance spectroscopy (EIS) data, recorded in the range (1 mHz - Hz), reveals a predominant bulk contribution with a low depletion angle of 3° and a pseudo capacitive behavior. As application, AgCoO2 is tested for the hydrogen production upon visible illumination owing to the potential of its conduction band (?0.83 VSCE), less cathodic than that of H2O/H2 (~ ?0.5 VSCE). H2 evolution rate of 79 μmol g?1 min?1 is determined at neutral pH with a quantum yield of 1.92% in presence of NO2? as hole scavenger; no Ag deposition was observed after photocatalysis.
关键词： Delafossite AgCoO2,Co-precipitation,Nano sized,Hydrogen,Photo electrochemistry
更新于2025-09-09 09:28:46
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Co-precipitation synthesis, structural characterization and fluorescent analysis of Nd3+ doped Y3Al5O12 and Yb3Al5O12 nanocrystallines
摘要： Nd3+, as one of the most important rare-earth (RE) ion, has been playing a significant role in pumping the infrared (IR) light. Depending on different synthesis strategies, doping content, and crystal lattice, however, Nd3+ always shows different IR intensity. In this work, we have fabricated two series of Nd3+ doped nanocrystallines that share with the same crystal structure, i.e., Nd3+ doped Y3Al5O12 (YAG) and Yb3Al5O12 (YbAG), through using the co-precipitation synthesis method while the ammonium bicarbonate as the precipitant agent. To reveal the influence of the synthesis conditions (e.g., synthetic temperature and pH value) on structural and florescent properties of Nd3+ doped YAG and YbAG nanocrystallines, several techniques have been performed in this work, including the X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric-differential scanning calorimeter (TG-DSC), Fourier transform infrared (FT-IR) spectroscopy, Raman and florescent spectroscopy spectra. Our results reveal that the optimal synthesis conditions are 1000?°C and pH 8 for YAG:Nd3+ and 900?°C and pH 9 for YbAG:Nd3+. Moreover, we also find the optimal Nd3+ doping contents of the YAG:Nd3+ and YbAG:Nd3+ nanocrystallines are 3% and 1.5%, which correspond to the strongest fluorescent intensity upon excitation at 808?nm and 980?nm, respectively. Typically, we reveal that substitution of Y with Yb ions could allow to enhancing the Nd3+ fluorescent intensity upon excitation at 808?nm. This work provides new insights into designing excellent crystal materials that can allow us to realize the laser transparent ceramics.
关键词： Nd3+ doped YbAG,fluorescent analysis,Nd3+ doped YAG,co-precipitation synthesis,structural characterization
更新于2025-09-09 09:28:46
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VO <i> <sub/>n</sub></i> Complexes in RTA Treated Czochralski Silicon Wafers Investigated by FTIR Spectroscopy
摘要： Oxygen-vacancy complexes formed after rapid thermal annealing in silicon wafers were investigated by FTIR spectroscopy at 6 K. It was found that VO4 is the only detectable complex. The concentration of VO4 complexes increases with increasing temperature of RTA treatment in the temperature range between 1250?C and 1400?C. The concentration at maximal temperature is equal to 4.5 × 1013 cm?3. The experimental results were compared with concentrations of VOn complexes in silicon wafers obtained using ab-initio calculations combined with rate equation modelling. The simulated concentration of VO4 corresponds well to the measured concentration. The bulk microdefect density increases with increasing VO4 concentration. The vacancies stored in VOn complexes after RTA are slowly released during further annealing and enhance oxide precipitation.
关键词： VO4 complexes,silicon wafers,Rapid thermal annealing,FTIR spectroscopy,oxygen precipitation
更新于2025-09-09 09:28:46
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Particle size effect on the dielectric properties of ZnO nanoparticles
摘要： Zinc oxide (ZnO) nanoparticles with di?erent particle sizes were synthesized by thermal annealing T A of zinc hydroxide at various temperatures. X-ray di?raction measurements show that all nanoparticles possess a typical wurtzite structure and no other impurity phases are observed. The average particle size (d ) increases from 22 to 98 nm as T A increases from 100 to 850?C. The dielectric properties of nanocrystalline ZnO with various particle sizes were studied in the frequency range of 20 Hz to 1 MHz between 80 K and 320 K. Dielectric measurement indicates that the particle size of samples has great in?uence on the dielectric behavior of ZnO nanoparticles. The M ” curves show strong grain peaks in all ZnO nanoparticles, whereas only 22 nm and 98 nm particles show weak grain boundary peaks. In addition, the ac conductivity (σac) follows Jonscher,s power law for all ZnO nanoparticles, but two types of conduction mechanisms were observed. It is concluded that the σac behavior of 22-nm particles is well accounted by the correlated-barrier-hopping model (CBH), whereas the d >22-nm particles behavior is probably due to Quantum Tunneling Mechanism (QMT). The di?erent σac behavior can be attributed to the various defects in grain boundary and formation of inhomogeneous dielectric structures.
关键词： A. Oxide materials,C. Grain boundaries,B. Precipitation,D. X-ray di?raction,C. Dielectric response,A. Semiconductors
更新于2025-09-09 09:28:46
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Solvent Assisted Synthesis of Tin-Zinc Oxide Nanoparticles: Structural Characterization and Antimicrobial Activity
摘要： Tin oxide doped zinc oxide nanoparticles (SnO2/ZnO) were prepared via deposition precipitation method with different molar ratios of tin oxide and effect of variation of concentrations of dopant (SnO2) was observed for physical and chemical properties of these nanoparticle. The structural properties of nanoparticles were characterized by thermogravimetric analysis, fourier transform infrared spectrometry, powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Their crystallite and structural properties deduced a clear decrement in crystallite size from 9.95 to 2.54 nm. Doping of tin significantly enhanced the photoluminescence and antibacterial properties of SnO2/ZnO nanoparticles. The photoluminescence studies exhibited a strong emission of green-yellow band at 470 nm. The antibacterial activities of these nanoparticles were investigated against Pasteurellamultocida and Escherichia coli by using disc diffusion method.
关键词： Deposition precipitation,SnO2/ZnO,Antimicrobial activity,Photoluminescence
更新于2025-09-09 09:28:46
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Optimization of the liquid–liquid interfacial precipitation method for the synthesis of $$\hbox {C}_{60}$$C60 nanotubes
摘要： Tubular fullerene nanowhiskers called ‘fullerene nanotubes’ are composed of C60 fullerene molecules (C60 NTs) are synthesized at room temperature using the liquid–liquid interfacial precipitation method in the pyridine and isopropyl alcohol (IPA) system. The growth control of fullerene nanotubes is important for their chemical and physical properties as well as for their future applications. In the present study, we investigated the effect of light, water, solvent ratio and temperature on the synthesis of C60 nanotubes. A marked development in the yield of C60 NTs was achieved using dehydrated solvents, a solution with a volume ratio of 1:9 for pyridine: IPA, a growth temperature equal to 5?C and by illuminating the C60-pyridine solution with ultraviolet light (wavelength 302 nm) for 102 h. The synthesized fullerene nanotubes were characterized by different analytical techniques including Raman and Fourier transform infrared spectroscopy, optical microscopy, focussed ion beam scanning electron microscopy and transmission electron microscopy.
关键词： solution growth,liquid–liquid interfacial precipitation method,light,temperature,solvent,Fullerene nanotubes
更新于2025-09-09 09:28:46
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Synthesis and Pholuminescence studies of polymer capped SnO2 nanoparticles synthesized by chemical co-precipitation method
摘要： In recent years many research works have been focused on the electrical and optical properties of metal oxides. In this present paper SnO2 nanoparticles have been synthesized by chemical co-precipitation method using different capping agents like EDTA (ethylene diamine tetra acetic acid), PVP (polyvinylpyrrolidone), PVA (polyvinyl alcohol) and studied the influence of capping agent on various properties of SnO2 nanoparticles. Structural, surface morphology, chemical analysis and luminescence properties of prepared SnO2 nanoparticles were studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) attached with energy dispersive analysis of X-rays (EDAX) and photoluminescence studies (PL). X-ray diffraction study reveals the nano-size particle distribution of the prepared samples with tetragonal rutile structure in the range of 3 to 9 nm. FTIR spectra show the structural confirmation of SnO2 nanoparticles. Various PL signals were observed in the visible region around 375 nm to 600 nm due to oxygen vacancies and interfacial Sn vacancies present in the prepared nanosamples.
关键词： X-ray diffraction,scanning electron microscopy,Nano-size distribution,Chemical co-precipitation,Photoluminescence
更新于2025-09-04 15:30:14