- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Synthesis and characterization of TiO2/ZnCr2O4 core-shell structure and its photocatalytic and antibacterial activity
摘要： A shell of ZnCr2O4 spinel was facilely covered on the surface of TiO2 nanoparticles to synthesize TiO2/ZnCr2O4 core-shell structure using TiO2 seed particles and heterogeneous precipitation. The as-prepared nanocomposite was characterized in terms of crystal structure, morphology and surface area, light absorption and band gap. After coupling TiO2 with ZnCr2O4, a heterojunction formed between the two semiconductor materials. UV–vis absorption spectra showed a red shift of the absorption edges and lower band gap of 3.0 eV for the composite system compared to the single phase TiO2 (3.4 eV) due to the formation of new energy level at the core-shell interface. Photocatalytic activity of the nanocomposites was evaluated by degradation of methylen blue under UV-light irradiation, revealing that the core-shell nanocomosite exhibits superior photocatalytic activity (99% yield) compared to the single phase TiO2 (40% yield) even after 4 consecutive reaction runs. In fact, this enhancement was attributed to the efficient separation and migration of the photogenerated electron–hole pairs at the core-shell interface due to the formation of energy bands heterojunction at the interface. Also, it was found that the synthesized core-shell structure is a highly effective antibacterial material against E. coli bacteria.
关键词： Heterogeneous precipitation,TiO2,ZnCr2O4,Antibacterial,Photocatalyst
更新于2025-09-10 09:29:36
-
Low-temperature elemental mercury removal over TiO2 nanorods-supported MnOx-FeOx-CrOx
摘要： TiO2 nanorods-supported MnOx, FeOx, CrOx, and MnOx-FeOx-CrOx catalysts have been prepared by a deposition-precipitation method, with the aim of investigating the combination of ternary metal oxides effect on elemental mercury (Hg0) removal. The TiO2 nanorods-supported MnOx-FeOx-CrOx catalyst manifested the superior Hg0 removal efficiency (~80-83%) at low temperatures (100-200°C) in the presence of O2. The addition of NO promoted the Hg0 removal efficiency under the same reaction conditions. Further, SEM, HRTEM, XRD, BET surface area, and XPS characterization were carried out to explore the physicochemical properties of the catalysts. It was found that the integration of three active metal oxides contributed to the enrichment of active sites and the surface adsorbed oxygen species, which facilitated to enhance the catalytic activity. Additionally, both the large surface area and high crystallization of the obtained TiO2 nanorods resulted in uniform dispersion of the manganese-iron-chromium mixed metal oxide nanoparticles and a high activity. Further, XPS data of spent MnOx-FeOx-CrOx/TiO2 catalyst indicated that the presence of Mn4+, Cr6+, and Fe3+ could promote Hg0 oxidation due to the strong synergistic interaction between the TiO2 nanorods-incorporated MnOx, FeOx, and CrOx nanoparticles.
关键词： Deposition-precipitation,MnOx-FeOx-CrOx,Synergistic interaction,TiO2 nanorods,Flue gas,Hg0 removal
更新于2025-09-10 09:29:36
-
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
-
The effects of gadolinium doping on the structural, morphological, optical, and photoluminescence properties of zinc oxide nanoparticles prepared by co-precipitation method
摘要： Pure and gadolinium (Gd)-doped zinc oxide (ZnO) nanoparticles were prepared by co-precipitation method. The EDS analysis confirmed the presence of Gd3+ ions in ZnO lattice. The X-ray diffraction measurement indicated the formation of hexagonal wurtzite structure for both pure and Gd-doped ZnO nanoparticles. The structural parameters of nanoparticles such as lattice constant, crystallite size, dislocation density, micro strain and other lattice parameters were calculated from XRD data. FESEM images of nanoparticles showed that the grain morphology of nanoparticles tends to hexagonal form by introducing Gd3+ ions into the ZnO lattice. The presence of functional groups and chemical bonding attributed to ZnO was confirmed by FT-IR measurement. The optical properties of nanoparticles were investigated by UV–Vis spectroscopy. The UV–Vis absorbance spectra, for Gd-doped samples, illustrated a blue shift by increasing Gd concentration. Also, the band gap of nanoparticles increased by increasing Gd concentration. The photoluminescence spectra of Gd-doped nanoparticles showed that the intensity of green luminescence increases by substitution of Gd3+ ions into the ZnO lattice attributed to the oxygen vacancies.
关键词： structural properties,morphological properties,co-precipitation method,gadolinium doping,zinc oxide nanoparticles,optical properties,photoluminescence properties
更新于2025-09-10 09:29:36
-
Functional properties of LaxCe1?xO2?δ nanocrystals and their bulk ceramics
摘要： Structure–property correlations were investigated for LaxCe1?xO2?δ (x = 0.05, 0.15) system (for both nanoparticles and ceramic). The nanoparticles were synthesized by the co-precipitation route and characterized for their structural, catalytic and visible light driven photocatalytic properties. Synthesised LaxCe1?xO2?δ nanopowders depicted phase purity with excellent compositional control as confirmed by various structural characterisation tools. The 15% La3+-doped ceria nanoparticles portrayed superior photocatalytic properties; complete degradation (99%) of the methylene blue dye was observed within 60 min of visible light irradiation under an alkaline medium. High density (> 96%) of the ceramics (sintered at 1580 °C for 2 h) confirmed promising sinterability of the synthesised powders. The ionic conductivities of the LaxCe1?xO2?δ ceramics increased with temperature and frequency owing to enhanced oxygen vacancies in the ceria matrix as a result of doping (of La3+-ions); a maximum conductivity of ~ 8.4 × 10?2 S cm?1 was obtained at 900 °C for the 15% La3+-doped ceria ceramics at 1 MHz frequency.
关键词： LaxCe1?xO2?δ,nanocrystals,photocatalytic properties,co-precipitation,ionic conductivity,bulk ceramics
更新于2025-09-10 09:29:36
-
Color-tunable particles through affinity interactions between water-insoluble protein and soluble dyes
摘要： This research is focused on the delivery of color using zein particles as a carrier and contributes to understanding the interactions between colorants and zein. Co-precipitation of purified zein protein with anionic dyes such as sulfonate group containing azo-dyes (patent blue sodium salt, azorubine, and fast green FCF) are used to prepare red, green, and blue colored nanoparticles. These dyes had electrostatic interactions with zein and they remained bound in the zein particles even after dialysis. This was not the case for purpurin, for with hydrogen bonding was expected as interaction. Upon increasing dye concentration, the particle sizes increased as a result of a change in the kinetics of precipitation, which was affected by the association between zein and the dye. However, the encapsulation efficiency continued to be very high and no plateau was reached for the used concentrations. The post-addition of dye on undyed zein particles was used to confirm that there is indeed a high affinity between the dye and the protein. The amount of free dye was determined and the affinity was again found to be high (dye adsorption ?95%). The amount of dye incorporated into the particles and the resulting color were similar using both techniques. These results show that there is a high affinity between the zein protein and the dye, and may be exploited to produce bio-based and optically-functionalized nanoparticles using zein as a carrier.
关键词： Zein,dye,color determination,interaction,co-precipitation
更新于2025-09-10 09:29:36
-
Calcium to phosphate ratio measurements in calcium phosphates using LIBS
摘要： In this study, we report the measurement of Ca/P ratio of hydroxyapatite using LIBS. Hydroxyapatite was prepared by wet chemical precipitation method with different stoichiometric ratios of Ca and P (1.5, 1.6, 1.67, 1.70, 1.80). Samples were then pelletized using KBr as a binder under a hydraulic press. Samples were irradiated with a laser beam and corresponding spectra were recorded. Spectra were further analyzed to calculate the Ca/P ratio which was then compared with the EDX for validation. LIBS results showed promise with a deviation of < 5% with the Stoichiometric ratios and EDX results.
关键词： EDX,Ca/P ratio,LIBS,hydroxyapatite,wet chemical precipitation
更新于2025-09-10 09:29:36
-
Eu:Lu2O3 transparent ceramics fabricated by vacuum sintering of co-precipitated nanopowders
摘要： Europium doped lutetium oxide (Eu:Lu2O3) nanopowders were synthesized by a co-precipitation method using hydrogen carbonate (AHC) as a precipitant. Influence of the terminal pH value on properties of the Eu:Lu2O3 precursors and calcined powders was investigated. It is found that the terminal pH value has little influence on compositions of the precursors, and all the powders calcined at 1100 °C show good crystallinity. However, the terminal pH value has significant influence on morphology and agglomeration degree of both the precursors and the calcined powders. The powders are found to have the optimal dispersity with the average particle size of 68 nm when the terminal pH is 6.57. Using the nanopowders as starting materials, Eu:Lu2O3 transparent ceramics were fabricated by vacuum sintering at 1700 °C for 30 h. The ceramics prepared from the powders whose terminal pH is 6.57 were found to have the best transparency and the in-line transmittance reaches 68% at 611 nm. The influence of vacuum sintering temperatures on the microstructure and transmittance of the Eu:Lu2O3 transparent ceramics was also investigated. The Eu:Lu2O3 ceramics sintered at 1825 °C for 30 h show the highest in-line transmittance of 72% at 611 nm. The average grain size of the prepared Eu:Lu2O3 ceramics is about 454 μm and the light output of the sample is about 10 times higher than that of commercial BGO single crystal.
关键词： Vacuum sintering,Eu:Lu2O3 transparent ceramics,Terminal pH value,Co-precipitation method,Light yield,Microstructure
更新于2025-09-10 09:29:36
-
Large-scale synthesis of size-controllable Ag nanoparticles by reducing silver halide colloids with different sizes
摘要： In present study, double-jet precipitation method was employed to prepare the uniform AgX (X: Cl, Br, I) colloids, and then ascorbic acid/sodium borohydride was respectively used to reduce AgX into the silver nanoparticles (Ag NPs). The main experimental parameters about above two processes were investigated. It was found that under the same synthesis conditions the size of obtained Ag NPS was strongly dependent on the AgX size，and the silver particles obtained by reduction of AgCl, AgBr and AgI had the monotonously diminishing size order. SEM, TEM, XRD, and UV spectrometry were employed to characterize the obtained AgX and Ag NPs respectively, and they gave the size variation clearly and the mechanism was discussed.
关键词： Silver halide,Controllable,Double-jet precipitation,Reduction,Ag nanoparticles
更新于2025-09-10 09:29:36
-
Structural, optical and magnetic properties of nanophase NiWO4 for potential applications
摘要： Nanocrystalline NiWO4 powder samples were synthesized by direct-chemical precipitation method. Thermal stability of the sample was studied by thermo gravimetric and differential thermal analysis. Structural characterization of NiWO4 nanoparticles was done with X-ray diffraction and field emission scanning electron microscopy. Elemental analysis of the samples were done with energy dispersive X-ray spectroscopy. Vibration modes of as prepared samples were analysed using Fourier transform infrared spectroscopy and Raman spectroscopy. Optical properties of the samples were explored using UV-vis spectroscopy and photoluminescence (PL) spectroscopy. Magnetic properties of NiWO4 nanoparticles were analysed using vibrating sample magnetometer (VSM). Effect of calcination temperature on structural, vibrational, optical and magnetic properties of the NiWO4 samples were also investigated. The results obtained from various characterization techniques found that NiWO4 nanoparticle have the potential use in light emitting diodes (LEDs), biomedical and sensing applications.
关键词： NiWO4,thermal stability,optical properties,nanoparticles,magnetic properties,direct-chemical precipitation,structural characterization
更新于2025-09-09 09:28:46