共查询到20条相似文献,搜索用时 15 毫秒
1.
Naif Ahmed Alshehri Aled R. Lewis Cameron Pleydell-Pearce Thierry G.G. Maffeis 《Journal of Saudi Chemical Society》2018,22(5):538-545
Zinc oxide nano-wires (ZnO NWs) are synthesized reproducibly with high yield via a low temperature hydrothermal technique. The influence of the growth duration time, growth temperature, zinc precursor and base concentration of Na2CO3 on the morphology of NWs is investigated. The growth products are characterised using scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL). SEM analysis shows that the optimum growth temperature is 140 °C and finds that length and diameter of ZnO NWs have a relationship with growth duration time and base concentrations of Na2CO3. In addition, it is reported that a high (~90%) yield of ZnO NWs can be synthesised via using any of three different precursors: zinc chloride, zinc acetate and zinc nitrate. TEM and XRD results indicate the high purity and the single crystalline nature of the ZnO NWs. XPS confirms the absence of sodium contaminants on the surface and indicates a near flat band surface condition. PL shows a large visible band in the yellow part of the spectrum, and a small exciton emission peak, indicating a large defect concentration, which is reduced after annealing in air. 相似文献
2.
Co3S4 nanocrystals were synthesized via a hydrothermal technique by adding thioglycolic acid and Co(CH3COO)2·4H2O as the precursors. The effect of some parameters, such as the reaction time and temperature and concentration of reactants, on the growth and morphology of the nano-structures has been studied. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) spectroscopy and Fourier transform infrared (FT-IR) spectra. 相似文献
3.
Mohammad Hossein Habibi Amir Hossein Habibi 《Journal of Thermal Analysis and Calorimetry》2013,113(2):843-847
Zinc ferrite nanocomposite was synthesized via thermal decomposition of zinc acetate and iron nitrate at three different temperatures (350, 450, and 550 °C). The influence of the thermal decomposition of precursors on the formation zinc ferrites was studied by differential thermal gravimetry and thermogravimetry (TG). The TG curve shows two steps for the thermal decomposition with mass loss of 17.3 % at 78 °C and 63.3 % at 315 °C. The prepared zinc ferrites nanocomposite was characterized by X-ray diffraction and scanning electron microscopy. The X-ray diffractograms of ZnFe2O4 shows that a crystalline phase, spinel system is formed. SEM micrograph of the zinc ferrite nanocomposite indicates the formation of uniformly spherical 48-nm nanograins. The properties of the zinc ferrite phase were strongly dependent on their calcinations temperature and molar ratio of precursors. 相似文献
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Co3O4 crystallites with particle, plate-, tube-, rod- and sheet-like morphologies were successfully prepared by the calcination
of the corresponding precursors synthesized via a precipitation or hydrothermal procedure. The morphologies of the precursors
and Co3O4 nano-tubes were detected by field emission scanning electron microscopy (FE-SEM). The as-obtained Co3O4 samples were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis
(TGA) and special surface area measurement (BET). The electrocatalytic activity of p-nitrophenol reduction with the Co3O4 products decorated on a glassy carbon electrode (GCE) was tested, respectively, using cyclic voltammetry (CV) in a basic
solution. The results indicated that p-nitrophenol was reduced with higher current density but almost at a constant potential on the Co3O4/GCE in contrast with that on a bare GCE at the same conditions. The highly catalytic activity of the as-prepared Co3O4 in a basic solution suggested their wide applications in environmental treatment or organic synthesis. 相似文献
6.
Malavika A. Bhide Joe A. Manzi Caroline E. Knapp Claire J. Carmalt 《Molecules (Basel, Switzerland)》2021,26(11)
A set of heteroleptic ethyl zinc β-amidoenoates (1, 2) and β-ketoiminates (3) of the form [LZnEt]2 with varying steric bulk have been synthesised via the reaction of diethylzinc with β-aminoenoate ligands HL1 and HL2 and β-ketoimine HL3. These complexes have been characterised via 1H and 13C NMR, mass spectrometry and single-crystal X-ray diffraction, which unambiguously determined all three structures as dimeric species in the solid state. We observe the unusual dimerisation of 1 and 2 through coordination of the central zinc atom to the methine carbon of the second monomer, which gives these complexes high reactivity. The thermal properties of complex 3 are explored via thermal gravimetric analysis (TGA), to investigate their potential as single-source precursors to zinc oxide, which shows that 3 has a significantly lower decomposition temperature as compared to its bis-ligated counterpart [Zn(L3)2], which gives 3 promise as a single-source precursor to zinc oxide. 相似文献
7.
Abbas-Ali Malek Barmi Mustafa Aghazadeh Hamid Mohammad Shiri Farzaneh Ghorab 《Russian Journal of Electrochemistry》2013,49(6):583-593
Particle, plate and flaky-like nanostructures of Y(OH)3 and Y2O3 were prepared via cathodic electrodeposition from nitrate bath by applying different current densities. In the first step, yttrium hydroxide precursors were cathodically grown on the cathode surface at the current densities of 2, 1, 0.5, 0.25 and 0.1 mA cm?2. The obtained hydroxide powders were heat-treated at 600°C for 3 h. The products were characterized by means of carbon, hydrogen and nitrogen (CHN), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and FT-IR spectroscopy. From the CHN, XRD and TG results, the mechanism of base electro generation at the applied conditions and the intercalation of nitrate ions in the deposit structure were proposed and confirmed. The results showed that the structural and morphological properties of the products are directly determined by the applied current density and it can be recognized as a main factor affecting in the cathodic electrodeposition of Y2O3. 相似文献
8.
Mustafa Aghazadeh Abbas-Ali Malek Barmi Hamid Mohammad Shiri 《Russian Journal of Electrochemistry》2013,49(4):344-353
Nanoparticles, nanospheres and nanorods of Y(OH)3 and Y2O3 were prepared via cathodic electrodeposition from chloride bath through applying different current densities. First, yttrium hydroxide precursors were cathodically grown on the cathode surface at the current densities of 2, 1, 0.5, 0.25 and 0.1 mA cm?2. Then hydroxide powders were heat-treated at 600°C for 3 h. The composition, crystal structure and morphology of the prepared oxide and hydroxide products were investigated by means of differential scanning calorimetery (DSC), X-ray diffraction (XRD), scanning and transmission electron microscopes (SEM and TEM) and FT-IR spectroscopy. Mechanism of base electrogeneration at the applied conditions, and intercalation of chloride ions in the deposit structure during the electrodeposition were proposed and confirmed by the XRD and TG analyses. The results showed that the structural and morphological properties of the products are directly dictated by the applied current density and it can be recognized as the main factor affecting on the cathodic electrodeposition of Y2O3. 相似文献
9.
以氯化亚铜,硝酸锌,氯化锡和硫脲作为反应前驱体,聚乙二醇作为模板,利用溶剂热方法合成Cu2ZnSnS4中空球。其中,聚乙二醇对于产物的最终形成起到关键作用。文章讨论了Cu2ZnSnS4中空球的生长机制,并通过X射线衍射(XRD)、拉曼光谱、场发射电子显微镜(FESEM)、透射电子显微镜(TEM)、X射线能量色散谱(EDX)、X射线光电子谱(XPS)、选区电子衍射谱(SAED)和紫外-可见光分光光度计(UV-Vis)等技术对样品的微结构以及光学性质进行了表征和分析。结果显示Cu2ZnSnS4中空球为四方晶体,尺寸为600 nm。其禁带宽度为1.52 eV,适用于制作光伏器件。 相似文献
10.
以氯化亚铜,硝酸锌,氯化锡和硫脲作为反应前驱体,聚乙二醇作为模板,利用溶剂热方法合成Cu2ZnSnS4中空球。其中,聚乙二醇对于产物的最终形成起到关键作用。文章讨论了Cu2ZnSnS4中空球的生长机制,并通过X射线衍射(XRD)、拉曼光谱、场发射电子显微镜(FESEM)、透射电子显微镜(TEM)、X射线能量色散谱(EDX)、X射线光电子谱(XPS)、选区电子衍射谱(SAED)和紫外-可见光分光光度计(UV-Vis)等技术对样品的微结构以及光学性质进行了表征和分析。结果显示Cu2ZnSnS4中空球为四方晶体,尺寸为600 nm。其禁带宽度为1.52 eV,适用于制作光伏器件。 相似文献
11.
Wei-Guo Tian Pan-Pan Wang Ling Ren Gen-Ban Sun Ling-Na Sun Kai Yang Bing-Qing Wei Chang-Wen Hu 《Journal of solid state chemistry》2007,180(12):3551-3559
A controllable synthesis of NiC2O4·2H2O nanorods precursor was obtained via the microemulsion-mediated solvothermal method and a further synthesis of β-Ni(OH)2 nanorods, nickel oxide (NiO) sub-microtubes, Ni nanospheres and flower-like nickel complexes nanostructures by using the precursor. The morphologies and crystalline structures were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and the X-ray powder diffraction (XRD). The morphologies and sizes of the precursors can be readily tuned by adjusting experimental parameters of the reverse microemulsion system. The synthesized β-Ni(OH)2 nanorods composed of fine nanosheets shown excellent electrochemical performance as an electrode material in rechargeable battery systems. 相似文献
12.
Dirk Steinborn Mario Rausch Ute Baumeister Ivan Poto
k Duan Miklo Michal Dunaj-Jur
o 《无机化学与普通化学杂志》1996,622(11):1941-1945
2-(1-Methyliminoethyl)phenol ( 1 a ) reacts with diethyl zinc to give bis[2-(1-methyliminoethyl)phenolato]zinc ( 3 ) via [2-(1-methyliminoethyl)phenolato]ethylzinc ( 2 ) as an intermediate. The complex 3 is also formed in the reaction of bis(trimethylsilyl)amide zinc with 1 a . The compounds were characterized by microanalysis, NMR (1H, 13C) and IR spectroscopy. X-ray structure analysis of the compounds 2 and 3 revealed that both compounds form in the solid state dimeric species where the monomeric units are bridged via two oxygen atoms forming a planar Zn2O2 ring with tetrahedral [ZnO2NC] and trigonal-bipyramidal [ZnO3N2] coordination of the zinc atom, respectively. 相似文献
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甲基芳烃气相氨氧化反应制备对应的芳香腈被认为是丙烯氨氧化制备丙烯腈之后化工领域又一重大进展,芳香腈是重要的精细化学品,广泛应用于医药、农药、颜料、染料、橡胶、光电材料等领域.其中2,6-二氯甲苯氨氧化反应制备2,6-二氯苯腈是特别重要的反应,2,6-二氯苯腈工业上可用于制备高效除草剂、杀菌剂及各种特种工程塑料;然而相较于其它的甲基芳烃,2,6-二氯甲苯由于甲基邻位有两个较大位阻且较强吸电子的氯原子影响,甲基活性较低,较难发生氨氧化反应,原料转化率和产品收率均较低.本课题组一直致力于发展高活性和选择性的氨氧化催化剂以及有效的策略实现甲基芳烃高效转化为芳香腈,我们曾以硅胶负载的钒磷氧化物(VPO/SiO_2)和钒铬氧化物(VCrO/SiO_2)为催化剂,成功实现了2,6-二氯甲苯氨氧化反应制备2,6-二氯苯腈.钒铬复合氧化物(VCrO)具有广泛的应用,可用于多相催化、气体传感、能量储存等领域.VCrO通常通过高温固相反应制备,然而一般得到的是混合相,产品形态和颗粒大小也不能很好控制;当用于氧化或氨氧化反应时,需要较高的反应温度,原料也容易发生过度氧化,导致积碳及活性降低.我们以V_2O_5和CrO_3为原料,在醇或者醇水溶液中于180℃进行溶剂热反应制备了无定形的VCrO前驱体,然后将前驱体在不同温度下氮气气氛中煅烧,产品通过粉末X射线衍射、透射电镜和X射线光电子能谱等进行表征.当以甲醇或甲醇水溶液为溶剂热反应介质,并且前驱体700℃进行煅烧后,产品为纯的正交晶系CrVO4纳米晶相;当以甲醇为溶剂时,CrVO_4晶相的尺寸大约为500 nm;而改为甲醇水溶液为溶剂时,产品尺寸急剧减小到50 nm以下,而且通过改变甲醇和水的体积比分别为10:1,5:1,1:1和1:5时,CrVO_4纳米晶相的尺寸从50 nm逐渐减小到30,20和10 nm,能够进行有效调控.据我们所知,这是首次合成纯的CrVO_4纳米晶相.我们以该纳米CrVO4为催化剂催化2,6-二氯甲苯氨氧化反应制备2,6-二氯苯腈,在335℃的相对较低温度下反应,原料转化率为84%,产品收率为75%;进一步升高温度到390℃,原料转化率为99%,产品收率可达81%.在所有已报道的二元复合氧化物催化剂中,纳米CrVO_4显示了最高的催化活性,主要归功于它较小的粒子尺寸、较大的表面积和更多暴露的活性中心 相似文献
15.
Much effort has been devoted to the synthesis of novel nanostructured materials because of their unique properties and potential applications. Bismuth subcarbonate ((BiO)2CO3) is one of commonly used antibacterial agents against Helicobacter pylori (H. pylori). Different (BiO)2CO3 nanostructures such as cube-like nanoparticles, nanobars and nanoplates, were fabricated from bismuth nitrate via a simple solvothermal method. The nanostructures were characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). It was found that the solvents and precursors have an influence on the morphologies of (BiO)2CO3 nanostructures. The possible formation mechanism of different (BiO)2CO3 nanostructures fabricated under different conditions was also discussed. 相似文献
16.
The nanometric precursors of neodymium oxide of various morphologies were prepared via a hydrothermal reaction route. The precursors and their thermal evolution to neodymium oxide phase were characterised by means of X-ray diffraction (XRD), transmission electron microscopy (TEM, HRTEM), thermal analysis (TG, DTA, EGA-MS), FTIR and atomic force microscopy (AFM). It was found that the reaction conditions (temperature, pressure) played a key role for the product formation of desired morphology and structure. At mild conditions (140 °C) precursor with unusual fibrous morphology and Nd(OH)2.45(Ac)0.550.45H2O stoichiometry was obtained. Upon heating this phase transformed, via intermediate cubic oxide, into trigonal Nd2O3 at 800 °C. Nd(OH)3 hydroxide obtained at severe conditions (180 °C) transformed upon heating into cubic Nd2O3 phase at about 500 °C and this phase was stabilised even at 800 °C. The fibrous precursors appeared to be a convenient material for preparation of homogeneous thin coatings on planar substrates is shown. 相似文献
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CdCO3 nanostructures were synthesized via simple hydrothermal method by Cd(NO3)2, ethylenediamine and hydrazine as reagents. The products were characterized with X-ray diffraction scanning electron microscopy, energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. Different parameter’s effect on product size and morphology were investigated. 相似文献
18.
Mohammad Hossein Habibi Elham Askari 《Journal of Thermal Analysis and Calorimetry》2013,111(2):1345-1349
Nanocrystalline manganese-doped zinc oxide was synthesized by thermal decomposition of a zinc oxide sol with two new dinuclear manganese(III) complexes as precursor. Thermal analysis results indicated that the decomposition of manganese precursors occurred at 269 and 314 °C. X-ray structural analysis shows the presence of dimanganese core in the complexes and the binding of the ligands to the manganese(III) is through N2O2. The manganese-doped zinc oxide composite was characterized by means of X-ray diffraction, scanning electron microscopy, and UV–Vis spectroscopy. Structural properties of the composites elucidated that the manganese ions have substituted the zinc ions without changing the wurtzite structure of zinc oxide. 相似文献
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This paper reports on a novel processing route for producing ZnO nanoparticles by solid-state thermal decomposition of zinc(II) acetate nanostructures obtained by the sublimation of zinc(II) acetate powder. The sublimation process of the Zn(OAc)2 powder was carried out in the temperature 150 °C for 2 h. In addition, nanoparticles of ZnO were obtained by solid-state thermal decomposition of the synthesized Zn(OAc)2 nanostructures. The synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, photoluminescence spectroscopy, and energy dispersive X-ray spectroscopy. The sublimation process of the Zn(OAc)2 powder was carried out within the range of 150–180 °C. The XRD studies indicated the production of pure hexagonal ZnO nanoparticles after thermal decomposition. 相似文献
20.
Mehdi Ranjbar Mohammad Ali Taher S. Mostafa Hosseinpour-Mashkani 《Journal of Cluster Science》2013,24(4):959-967
In the present study, Nano-sized magnesium aluminate powders were successfully synthesized via microwave process based on the reaction between Mg (NO3)2·6H2O and Al (NO3)3·9H2O in distilled water, at various conditions. The products were characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy, photoluminescence (PL) spectroscopy, and EDAX analysis. The effects of different parameters such as reaction time and microwave power on the morphology, particle size, and PL properties of the product were studied by SEM images and the PL. 相似文献