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1.
ZrO 2 nanoparticles were synthesized through arc discharge of zirconium electrodes in deionized (DI) water. X-ray diffraction (XRD) analysis of the as prepared nanoparticles indicates formation a mixture of nanocrystalline ZrO 2 monoclinic and tetragonal phase structures. Transmission electron microscopy (TEM) images illustrate spherical ZrO 2 nanoparticles with 7–30 nm diameter range, which were formed during the discharge process with 10 A arc current. The average particle size was found to increase with the increasing arc current. X-ray photoelectron spectroscopy (XPS) analysis confirms formation of ZrO 2 at the surface of the nanoparticles. Surface area of the sample prepared at 10 A arc current, measured by BET analysis, was 44 m 2/g. Photodegradation of Rhodamine B (Rh. B) shows that the prepared samples at lower currents have a higher photocatalytic activity due to larger surface area and smaller particle size. 相似文献
2.
In this letter, we present a facile route to produce metastable tetragonal zirconia (ZrO 2) nanoparticles via pH-controlled precipitation of dilute zirconyl nitrate dihydrate [ZrO(NO 3) 2·2H 2O] solution in liquid NH 3 under ambient conditions and calcination at 500 °C for 2 h. The phase pure tetragonal ZrO 2 nanoparticles are obtained at pH 9. The effect of pH on metastable phase stabilization in precipitated ZrO 2 nanoparticles is demonstrated with the help of XRD, SEM/EDX, and X-ray photoelectron spectroscopy techniques. The stability of tetragonal ZrO 2 phase is attributed to the smaller crystallite size and greater oxygen deficiency in phase-pure tetragonal ZrO 2. 相似文献
3.
On the basis of w/o microemulsion and surfactant template‐assembly technology, tube‐like ZrO 2/NaCl was prepared using sodium bicarbonate as precipitant. The w/o microemulsion consisted of a nonionic surfactant OP emulsifier, cosurfactant pentanol and oil hexamethylene alkyl. The morphology, structure, and optical properties of the tube‐like ZrO 2/NaCl have been studied by SEM, XRD, FTIR, UV‐vis, and PL techniques. 相似文献
4.
In this paper, Bi 2O 3 and rare earth (La, Ce)‐doped Bi 2O 3 visible‐light‐driven photocatalysts were prepared in a Triton X‐100/ n‐hexanol/cyclohexane/water reverse microemulsion. The resulting materials were characterized by X‐ray powder diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface area, photoluminescence spectra (PLS) and UV–Vis diffuse reflectance spectroscopy. The XRD patterns of the as‐prepared catalysts calcined at 500°C exhibited only the characteristic peaks of monoclinic α‐Bi 2O 3. PLS analysis implied that the separation efficiency for electron‐hole has been enhanced when Bi 2O 3 was doped with rare earth. UV–Vis diffuse reflectance spectroscopy measurements presented an extension of light absorption into the visible region. The photocatalytic activity of the samples was evaluated by degradation of methyl orange (MO) and 2,4‐dichlorophenol (2,4‐DCP). The results displayed that the photocatalytic activity of rare earth‐doped Bi 2O 3 was higher than that of dopant‐free Bi 2O 3. The optimal dopant amount of La or Ce was 1.0 mol%. And the mechanisms of influence on the photocatalytic activity of the catalysts were discussed. 相似文献
5.
Highly crystallized mesoporous ZrO 2 nanomaterials were synthesized by solvent evaporation induced self‐assembly approach. Ordered mesoporous ZrO 2 nanomaterials were characterized by TEM, SEM, BET, XRD and UV‐Vis spectroscopy. The obtained nanomaterials exhibit the close‐packing mesopores with average pore size of 7 nm and a highly crystallized framework with tetragonal phase. A non‐enzyme electrochemical sensor based on ordered mesoporous ZrO 2 is established for selective detection of methyl parathion (MP). The online extraction of MP is firstly achieved by ZrO 2 modified electrode at open‐circuit potential for 5 min., and the sensitive detection of MP is performed by differential pulse voltammetry (DPV) method. By comparison, DPV responses of mesoporous ZrO 2 are 40 times and 25 times larger than that of mesoporous silica and mesoporous carbon with the similar pore structure, implying the specific affinity advantage of zirconia to phosphoric group. The quantitative analysis result shows that the voltammetric currents are linear with concentrations of MP ranging from 1 ng/ml to 2 μg/ml with a detection limit of 0.53 ng/ml. The sensor also exhibits good stability and high selectivity against interfering species. The excellent analytical performances are owed to the accessible and uniform mesoporous structures, highly crystallized frameworks of ZrO 2 and its specific affinity to phosphate groups. 相似文献
6.
Crystalline ZrO 2 nanoparticles were prepared from zirconium isopropoxide by slow hydrolysis and subsequent hydrothermal treatment of solutions containing various amounts of sodium hydroxide at 180 °C. Whereas moderately basic solutions lead to the formation of nanoparticles of monoclinic ZrO 2 with plate-like morphology, and nanoparticles of the cubic ZrO 2 high-temperature polymorph with diameters of approx. 5 nm were obtained from strongly basic solutions. The morphology, structure and properties of as-synthesized nanoparticles were characterized using HRTEM, XRD, Raman spectroscopy, UV–vis, PL spectroscopy and BET measurements. The formation of both, the monoclinic and the cubic polymorph, was confirmed by electron microscopy and Raman spectroscopy. The crystallinity and morphology of the resulting ZrO 2 nanoparticles can be adjusted by the choice of the reaction conditions. The cubic ZrO 2 nanoparticles have a high surface area (300 m 2/g) and exhibit a strong photoluminescence in the UV region. 相似文献
7.
A common ionic liquid (IL), 1‐butyl‐3‐methylimidazolium tetrafluoroborate (bmimBF 4), is used as polar solvent to induce the formation of a reverse bmimBF 4‐in‐toluene IL microemulsion with the aid of the nonionic surfactant Triton X‐100. The swelling process of the microemulsion droplets by increasing bmimBF 4 content is detected by dynamic light scattering (DLS), conductivity, UV/Vis spectroscopy, and freeze‐fracture transmission electron microscopy (FF–TEM). The results show that the microemulsion droplets initially formed are enlarged by the addition of bmimBF 4. However, successive addition of bmimBF 4 lead to the appearance of large‐sized microemulsion droplet clusters (200–400 nm). NMR spectroscopic analysis reveal that the special structures and properties of bmimBF 4 and Triton X‐100 together with the polar nature of toluene contribute to the formation of such self‐assemblies. These unique self‐assembled structures of IL‐based microemulsion droplet clusters may have some unusual and unique properties with a number of interesting possibilities for potential applications. 相似文献
8.
Composite photocatalyst films have been fabricated by depositing BiVO 4 upon TiO 2 via a sequential ionic layer adsorption reaction (SILAR) method. The photocatalytic materials were investigated by XRD, TEM, UV/Vis diffuse reflectance, inductively coupled plasma optical emission spectrometry (ICP‐OES), XPS, photoluminescence and Mott–Schottky analyses. SILAR processing was found to deposit monoclinic‐scheelite BiVO 4 nanoparticles onto the surface, giving successive improvements in the films′ visible light harvesting. Electrochemical and valence band XPS studies revealed that the prepared heterojunctions have a type II band structure, with the BiVO 4 conduction band and valence band lying cathodically shifted from those of TiO 2. The photocatalytic activity of the films was measured by the decolourisation of the dye rhodamine 6G using λ>400 nm visible light. It was found that five SILAR cycles was optimal, with a pseudo‐first‐order rate constant of 0.004 min ?1. As a reference material, the same SILAR modification has been made to an inactive wide‐band‐gap ZrO 2 film, where the mismatch of conduction and valence band energies disallows charge separation. The photocatalytic activity of the BiVO 4–ZrO 2 system was found to be significantly reduced, highlighting the importance of charge separation across the interface. The mechanism of action of the photocatalysts has also been investigated, in particular the effect of self‐sensitisation by the model organic dye and the ability of the dye to inject electrons into the photocatalyst′s conduction band. 相似文献
9.
Cellulose-ZnO composite was achieved by microwave assisted dissolution of cellulose in ionic liquid 1-butyl-3-methylimidazolium chloride ([C 4mim]Cl) followed by addition of premixed ground of Zn(CH 3COO) 2·2H 2O and NaOH. Surface characterization, optical property and thermal stability of nanocomposite were determined by X-ray diffraction, scanning electron microscopy (SEM), UV–Vis spectroscopy and thermo gravimetric analysis. XRD patterns showed the ZnO in polymer matrix has the wurtzite structure. Presence of zinc oxide nanoparticles and cellulose fibers in the composites were observed by SEM. Band-edge transition of zinc oxide in the nanocomposite occurs in lower wavelength than bulk zinc oxide. Thermal stability of nanocomposite was lower than regenerated cellulose due to catalyst behavior of zinc oxide nanoparticles in cellulose matrix. 相似文献
10.
通过离子交换法将Ag纳米颗粒负载于玻璃微珠的表面及浅表层,并以钛酸四丁酯的乙醇溶液为前驱体,将TiO 2负载于包含银的玻璃微珠表面,制得一种玻璃微珠/Ag/TiO 2复合光催化剂。由于纳米银的表面等离子体吸收效应,该复合光催化剂具有一定的可见光响应特性。利用XRD、SEM对样品进行表征,可发现玻璃微珠表面形成一层均匀多孔的锐钛矿TiO 2,其粒径均在50 nm左右。由漫反射光谱可得出该催化剂具有较强的可见光吸收,并在降解甲基橙溶液的试验中表现出较好的可见光催化活性。 相似文献
11.
Cerium trifluoride have great potential in material applications for luminescent materials, composite materials or ionic conductors especially in the form of nanoparticles and nanoobjects. In this work, nanoparticles of CeF 3 were prepared by simple one pot reaction of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF 6) with CeO 2 and by reaction of CeO 2 with KPF 6 in ionic liquid 1-butyl-3-methylimidazolium chloride (bmimCl). Prepared nanoparticles were analyzed by XRD and SEM analysis. Average diameter of prepared nanoparticles resulting from Sherrer formula is 12 nm. Nanoparticles did not form ordered agglomerates and could be used in the form of separate nanoparticles which are desired in some applications. 相似文献
12.
New polypyrrole (PPy)-derived polymer/ZrO2 nanocomposite materials are prepared by single-step oxidative polymerization of pyrrole (Py) and/or N-methylpyrrole (mPy) in the presence of HCl-functionalized ZrO2 nanoparticles and ammonium persulfate. The physicochemical features of the PPy–ZrO2, poly(Py-co-mPy)–ZrO2 and PmPy–ZrO2 hybrids were analyzed by XPS, FTIR, XRD and UV–Vis techniques. To explore the advantages of these nanocomposites for potential applications, their thermal, conductive and electrochemical properties were investigated. The characterization reveals that a chemical bonding, based on electrostatic interactions, is established between the polymers and the ZrO2 nanoparticles. Interestingly, it is found that the growth of polymer on the surface of Cl-functionalized ZrO2 becomes more significant as the Py moiety (–NH– species) content in the polymer increases. The thermal stability and conductivity of the polymers increase by hybridization with the ZrO2 nanoparticles. This is assigned to the affective interaction of the polymers with the ZrO2 nanoparticles. Particularly, the resulting nanocomposites keep high conductivities, ranging between 0.323 and 0.929 S cm−1. Finally, voltammetric characterization shows that the PPy–ZrO2 and poly(Py-co-mPy)–ZrO2 nanocomposites are electroactive, thus demonstrating their capability for electrochemical applications. These results highlight the great influence of the nanoparticle interface and the nature of monomer on the nanocomposite formation and properties. 相似文献
13.
Co-doped ZnAl2O4 nanoparticles were prepared by hydrothermal method. The samples were characterized by XRD, HRTEM, EDX, FT-IR, XPS, PL, and UV–Vis, and the effects of cobalt doping on the microstructure and optical property of the samples were studied. The experimental results showed that Co-doped ZnAl2O4 nanoparticles synthesized by this method are single phase with cubic crystal structure, no other impurity phases were observed. Furthermore, with increasing the Co2+ concentration, the average crystallite size of the Co-doped samples became smaller. The absorption bands in FT-IR spectra are broadened in the low frequency region, the PL spectra had the red-shift and the UV–Vis peaks intensity gradually enhanced. 相似文献
14.
自行设计合成了新颖的苄胺型双链表面活性剂3,4-双十二烷氧基苄胺(DDOBA). 利用DDOBA/正丁醇/正庚烷/甲酸/HAuCl 4·4H 2O自发形成的水/油(W/O)型微乳液作为微反应器, 通过微波辐射下的甲酸还原法成功制备了DDOBA保护的憎水性金纳米粒子, 并通过紫外-可见(UV-Vis)光谱、透射电镜(TEM)、高分辨透射电镜(HR-TEM)和X射线衍射(XRD)等方法进行了表征和分析. 结果显示, DDOBA既可参与形成稳定的W/O型(油包水型)微乳液, 又可作为金纳米粒子的良好保护剂. 在合适的微乳液体系组成范围内, 用本实验方法可以获得高单分散性的憎水性金纳米粒子, 并能在空气/水界面上自动形成大面积短程有序的纳米金二维自组装膜. 相似文献
15.
The Ni 2P@Cd 0.5Zn 0.5S nanoparticles photocatalyzed self‐coupling of p‐xylene was reported here, and the corresponding coupling product 1,2‐di‐ p‐tolylethane was obtained. The reaction could be extended to toluene derivatives with electron‐donating and electron‐withdrawing substituents. Ni 2P@Cd 0.5Zn 0.5S nanoparticles had already been characterized by XRD, ICP‐AES, SEM, TEM, UV/Vis, FL, XPS. The Mott–Schottky curves of Ni 2P@Cd 0.5Zn 0.5S were made through electrochemical methods. An active carbon free‐radical was captured through ESR measurement under irradiation. The research demonstrated this photocatalytic system feasible for the self‐coupling reaction of toluene derivatives. 相似文献
16.
This study was focused on the photocatalytic activity of polyaniline (Pani)/iron doped titanium dioxide (Fe–TiO 2) composites for the degradation of methylene blue as a model dye. TiO 2 nanoparticles were doped with iron ions (Fe) using the wet impregnation method and the doped nanoparticles were further combined with Pani via an in situ polymerization method. For comparison purposes, Pani composites were also synthesized in the presence undoped TiO 2. The photocatalyst and the composites were characterized by standard analytical techniques such as FTIR, XRD, SEM, EDX and UV–Vis spectroscopies. Fe–TiO 2 and its composites exhibited enhanced photocatalytic activity under ultraviolet light irradiation. Improved photocatalytic activity of Fe–TiO 2 was attributed to the dopant Fe ions hindering the recombination of the photoinduced charge carriers. Pani/Fe–TiO 2 composite with 30?wt.% of TiO 2 nanoparticles achieved 28% dye removal and the discoloration rate of methylene blue for the sample was 0.0025?min ?1. FTIR, XRD, SEM, EDX and UV–Vis spectroscopies supported the idea that Fe ions integrated into TiO 2 crystal structure and Pani composites were successfully synthesized in the presence of the photocatalyst nanoparticles. The novelty of this study was to investigate the photocatalytic activity of Pani composites, containing iron doped TiO 2 and to compare their results with that of Pani/TiO 2. 相似文献
17.
The effects of penicillin potassium salt (PenK) on the solubility, Krafft temperature TK, critical micelle concentration CMC of SDS micelle and the phase behavior of SDS/n-C5H11OH/H2O system were studied. The partial phase diagrams of SDS/PenK/H2O system at different temperatures were determined. The release amounts of PenK in SDS/n-C5H11OH/H2O system and the distribution coefficient of PenK between micelle and water were measured by UV-Vis spectroscopy. The results show that in the presence of PenK, the CMC of SDS was decreased while the TK of SDS was increased and the solubility of SDS in both water and SDS/n-C5H11OH/H2O oil in water (O/W) microemulsion was decreased, but increased in water in oil (W/O) microemulsion. SDS micelles and SDS/n- C5H11OH/H20 O/W microemulsion could accelerate the release rate of PenK. The addition of SDS and water could both increase the release rate of PenK, whereas the presence of n-C5H11OH reduced the release rate of PenK. The above results were related to the electrostatic repulsion between PenK and SDS. 相似文献
18.
Zirconia based nanocomposites have attracted much research attention in recent years due to their exceptional biomedicinal activities. Rhizome extracts of Corallocarpus epigaeus based ZrO 2/CuO–ZnO nanocomposite were green synthesized in a facile synthesis strategy. The nanocomposites were examined with XRD technique for their structural information and FT-IR technique for surface functional group analysis. Electron microscopic images aided to elucidate the CuO and ZnO nanoparticles decorated ZrO 2 nanostructures. UV–vis absorption spectroscopic studies of the nanocomposite revealed the characteristic UV absorption of ZrO 2 and enhanced visible region absorption for the incorporated nanoparticles. Antibacterial and antifungal studies indicated enhanced activity of nanocomposites over the pristine zirconia nanoparticles. ZrO 2/CuO–ZnO nanocomposite had exhibited about 75% of α-amylase inhibition activity, whereas pristine ZrO 2 nanoparticles had exhibited only 57% suggesting the worthwhile application in the antidiabetic activity of the nanocomposite. 相似文献
19.
This paper describes a simple approach to determine gold nanoparticles in liver and river water samples. The method of purification of nanoparticles from the matrix is based on the stabilization of gold nanoparticles with a cationic surfactant followed by a microliquid-liquid extraction in ionic liquid. Finally, the extracted nanoparticles can be analysed by UV/Vis detection or Raman spectroscopy. The precision of the proposed method for the analysis of liver tissue and river water samples was 9.7% and 18% respectively for UV/Vis analysis. The sensitivity was 1.17 × 10(-12) M for the analysis of 3 mL of liver homogenate or river water sample. 相似文献
20.
Abstract The hydrolysis of cephanone in water, cetyl trimethyl ammonium bromide (CTAB) micelle, and CTAB/ n‐C 5H 11OH/H 2O O/W microemulsion was studied through UV‐VIS absorption spectroscopy. The mechanism of the hydrolysis and the effects of both the acidity of the media and the composition of O/W microemulsion on the hydrolysis were studied. The results show that the hydrolysis rate of cephanone increases with the acidity. Compared with water, CTAB micelle and CTAB/ n‐C 5H 11OH/H 2O O/W microemulsion suppress this hydrolysis. The inhibition of the hydrolysis of cephanone by CTAB micelle and CTAB/ n‐C 5H 11OH/H 2O O/W microemulsion is related to the location of cephanone in the interphases of CTAB micelles and CTAB/ n‐C 5H 11OH/H 2O O/W microemulsion droplets. 相似文献
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