钇复合氧化物颜料的制备与表征

通过尿素分解法,把三价铬离子掺入到钇铝石榴石Y₃Al₅O₁₂中,采用共沉淀法制备出绿色颜料。扫描电镜测试表明产物颗粒直径在200 nm左右,用XRD测试复合氧化物的结晶相行为,确定主相是钇铝石榴石相,用紫外可见漫反射光谱测试掺杂离子的配位状态和电子跃迁行为,用色度学测试氧化物颜色特征。将复合氧化物颜料颗粒与高分子聚丙烯共混,熔体纺丝,并通过北京同步辐射X射线CT对制得的纤维加以测试,结果表明复合氧化物颜料在高分子基质中得到良好的分散。这种颜料性能稳定,对环境友好,为实现无水印染技术奠定基础,减少纺织印染工业中所排放的污水。     

基于钛酸盐的黄色复合氧化物颜料的制备和光谱表征

我们利用乙酰丙酮制备钛、镍配合物前驱体,通过热处理,成功制备出黄色颜料。我们通过红外光谱,FT-Raman、XPS和XRD等多种表征手段对产物进行了表征研究。     

纳米复合氧化物LaMnO3的制备及表征

采用溶胶-凝胶法、共沉淀法、非晶态配位法三种不同的方法制备了纳米级的钙钛矿型复合氧化物LaMnO3,并通过XRD、FT-IR、ICP实验技术对所制备的系列纳米催化剂进行了表征。结果表明:3种不同的方法所制备的复合氧化物均形成了ABO3型钙钛矿型结构,都属于纳米颗粒,初步考察了制备条件对复合氧化微粒的形成结构的影响,非晶态配位法制备的LaMnO3平均粒度最小,溶胶-凝胶法制备的样品浓度最高。     

钙钛矿型纳米复合氧化物SrCoO_3的制备与表征

采用硬脂酸燃烧合成法制备了钙钛矿型纳米复合氧化物钴酸锶(SrCoO3),通过X射线衍射测试(XRD),红外光谱测试(IR)手段对所制备的系列纳米催化剂进行了表征。结果表明:所制目标产物钴酸锶为钙钛矿型,颗粒分布均匀,粒径在27纳米级。     

直接沉淀法制备纳米ZnO及表征

以硫酸锌和碳酸铵为原料,采用直接沉淀法制备了纳米ZnO,并探讨了浓度、温度、时间、洗涤液及操作方式等因素对样品的影响;采用GT-DTA、FT-IR、XRD、BET等对前驱物和纳米ZnO粉体结构和形貌进行了表征,结果表明:前驱物是[Zn5(OH)6(Co3)2],前驱物在300C培烧2h得到的纳米ZnO的粒径为15-22nm左右,分布较均匀、纯度高,并发现纳米晶须形状ZnO.     

Mo-Fe-Bi复合氧化物的制备和光谱研究

本文采用溶胶方法和沉淀方法制备Ｍｏ－Ｆｅ－Ｂｉ复合氧化物,用ＦＴＩＲ、ＮＩＲ ＦＴ－Ｒａｍａｎ和ＸＲＤ对其进行研究。     

LiFePO4纳米管的制备与表征

采用溶胶凝胶法在氧化铝模板中成功的制备了LiFePO4一维纳米管阵列．扫描电子显微镜和透射电子显微镜表征结果表明所制备的LiFePO4纳米管具有单分散性,互相平行,高度有序。综合选区电子衍射、X射线衍射以及X光线能谱表征结果,所制备的LiFePO4纳米管为单一的橄榄石型结构．这种在室温和温和条件下合成的一维LiFePO4纳米管,可以做为新型的锂离子电池正极材料．     

纳米钙钛矿La_xSr_(1-x)CoO_3复合氧化物的制备和表征

采用微乳液法和自燃烧法制备Sr掺杂的LaCoO3钙钛矿氧化物的陶瓷粉末,并对该钙钛矿氧化物结构进行了XRD,IR,及ICP-AES表征,从而将微乳液法与自燃烧法进行了对比,并研究了起始原料配比对产物粒径的影响。实验结果表明：在反应温度、反应时间、煅烧条件等一定的条件下采用适宜的原料配比,可制得平均粒径为12—20nm且粒径分布较均匀的LaxSr1-xCoO3。     

四氧化三钴粉末的沉淀法制备及表征

以硝酸钴为钴源,碳酸铵为沉淀剂,采用沉淀法制备四氧化三钴粉体。采用TG、XRD、IR、激光粒度分析仪等对前驱体碱式碳酸钴和产物四氧化三钴进行了表征及分析。研究了焙烧温度、反应物浓度和反应时间等因素对产物的影响。     

Synthesis and characterization of mixed vanadium oxide cathode materials for lithium-ion batteries

A family of mixed vanadium oxides LiCo_yNi_(1−y)VO₄ (x=0.2, 0.5 and 0.8) of potential use as high voltage cathode materials in lithium batteries, has been synthesized and characterized. In general the x-ray diffraction analysis showed that these compounds have an inverse spinel structure where about 85 % of the Ni²⁺ and Co²⁺ ions occupies octahedral sites and the rest tetrahedral sites along with the V⁵⁺ ions. Moreover, the annealing temperature plays a key role in determining the particle size, as demonstrated by scanning electron microscope analysis. Cycling voltammetry tests showed that the lithium insertion-extraction process in the LiCo_yNi_(1−y)VO₄ electrode materials occurs reversibly at around 4.3–4.4 V vs. Li and these results are confirmed by cycling tests. The cycling capacity is modest; however the trend of the cycling curves leads to foresee that an increase in capacity may be obtained by extending the charging process beyond 4.6 V vs. Li, once a stable electrolyte will be available. Paper presented at the 6th Euroconference on Solid State Ionics, Cetraro, Calabria, Italy, Sept. 12–19, 1999.     

Synthesis,characterization, and effect of concentration variation on metal oxide nanostructures

Zinc oxide (ZnO) has been successfully synthesized by an anodization method, and it has been fabricated through anodization method with different concentration of zinc nitrate. The element composition, surface inspection, structural, and morphological features of the products are depend on the concentration of zinc nitrate. At lower concentration (0.01M), SEM image shows ZnO nanowires with average width of about 30 and 50 nm. With increase in the concentration of zinc nitrate from 0.01 to 0.05 M, the nanowires change into the nanosheets with average width of about 0.5 and 1.5 μm. For samples (0.1 M) exhibits nanodots, morphology was composed of hundreds of nanosheets with thickness is about 90 nm on average. When the concentration increases to 0.2 M, the nanodots trench became bigger with diameter about 1.2–2.0 μm. When the concentration of zinc nitrate is 0.3 M, the average diameter of nanodots is about 2–2.5 μm. The trench of nanosheets becomes thinner and shorter, but the number of nanosheets increases with diameter 20–50 nm. The formation of nanowires, nanodots, and nanosheets nanostructures is also believed to result from actions on concentration of zinc nitrate as an aquas medium. The EDX result shows the atomic percentage (at.%) of the oxygen increased when the concentration of zinc nitrate increased. The pattern of EDX indicates that the ZnO nanostructures are composed of Zn, O, and Al. They represent Al composition in the sample because the anode using the aluminum rod during experiment.     

Colour and art: A brief history of pigments

Human beings have had an inherent urge to leave their mark in the form of works of art since prehistoric times. This has driven the quest for new and better pigments with which to make paints. This paper describes the origins and composition of earliest earth pigments used by primitive man to decorate the walls of caves through to the synthetic pigments developed in more recent times. Despite modern technology, the artist's palette remains a mixture of the pigments used by cave artists, natural pigments used in the middle ages, and modern organic compounds.     

Synthesis and characterization of nanostructure hydrous iron–titanium binary mixed oxide for arsenic sorption

Synthesis of nanostructure hydrous iron–titanium binary mixed oxide (NHITBMO) had been reported by a simple method, and characterized by the X-ray diffraction (XRD), thermal analysis, transmission electron microscope (TEM), Föurier Transform Infrared (FTIR), surface area, and zero surface charge pH (pHzpc). The synthetic oxide was hydrated and microcrystalline with 77.8 m² g^?1 BET surface area. The particle size (nm) calculated using XRD peak table and TEM image was ~10–13 and 6–8, respectively. The pH_zpc value was 6.0 (±0.05) for the oxide. The NHITBMO showed pH dependent good sorption affinity for arsenic from the aqueous solution and, the Langmuir monolayer capacity (mg g^?1) was 80.0 and 14.6, respectively, for the As(III) and As(V). The pseudo-second order equation described the room temperature arsenic sorption kinetic data well. The minimum dose required was 1.6 g NHITBMO per L of water (As_total = 0.24 mg L^?1) to reduce the arsenic level below 0.01 mg L^?1 in batch treatment process.     

Synthesis and structural characterization of mixed aluminum-gallium-offretites

A new synthesis procedure is reported for the preparation of mixed Al,Ga-offretites over the entire solid solution range 0 ≤ Ga/(Ga + Al) ≤ 1. The resulting materials are characterized by X-ray powder diffraction, adsorption microcalorimetry and multinuclear solid state NMR. The ²⁹Si MAS-NMR data are consistent with statistical occupancy of the T₁ and T₂ sites by aluminum and gallium, and also show no positive evidence for preferential siting effects between both framework metals. Isotropic chemical shifts and nuclear electric quadrupolar coupling constants for ²⁷Al and ⁷¹Ga have been obtained from a field-dependent analysis of the center of gravity in the MAS-NMR spectra. H-Al, Ga-offretites produced by ammonium exchange and subsequent calcination reveal evidence of partial demetallation of the framework with formation of extra-lattice metal species.     

Structural characterization of mixed Ta–Re oxide films

Thin films of mixed Ta and Re oxides have been produced by reactive dc magnetron co-sputtering of pure Ta and Re metal targets in Ar–O₂ atmosphere. The structural evolution of these films has been studied as a function of the composition, starting from a pure tantalum oxide film up to about 82% rhenium content. The composition and the structure of the films have been investigated by using X-ray diffraction and micro-Raman spectroscopy. For low Re content (20%), islands of a well crystallized phase, based on ReO₄ groups, appear in the films still composed by pure amorphous tantalum oxide, while a mixed disordered solid phase is found for the highest Re concentration (82%).     

Synthesis and electrical characterization of tungsten oxide nanowires

Tungsten oxide nanowires of diameters ranging from 7 to 200~nm are prepared on a tungsten rod substrate by using the chemical vapour deposition (CVD) method with vapour--solid (VS) mechanism. Tin powders are used to control oxygen concentration in the furnace, thereby assisting the growth of the tungsten oxide nanowires. The grown tungsten oxide nanowires are determined to be of crystalline W₁₈O₄₉. I--V curves are measured by an \textit{in situ} transmission electron microscope (TEM) to investigate the electrical properties of the nanowires. All of the I--V curves observed are symmetric, which reveals that the tungsten oxide nanowires are semiconducting. Quantitative analyses of the experimental I--V curves by using a metal--semiconductor--metal (MSM) model give some intrinsic parameters of the tungsten oxide nanowires, such as the carrier concentration, the carrier mobility and the conductivity.     

Characterization of pigments used in painting by means of laser-induced plasma and attenuated total reflectance FTIR spectroscopy

The study of pigments which are found in the works of art is one of the most important tasks in the examination of historic, artistic and archaeological materials since it can provide information about their source, the pictorial technique used or the presence of restoration works.In some studies, the historical, artistic and technical characterization of the artefact is not the final goal but its restoration. In those cases, the knowledge about the chemical composition inferred from the analysis of the artwork is crucial for conservators and restorers in order to ensure that the same pigments that were used in the original work are employed for the restoration.In this work, the analytical characterization of a range of different pigments commonly used in art has been carried out using laser-induced plasma (LIBS) and attenuated total reflectance (ATR)-FTIR spectroscopy. The main purpose of this study is to provide a preliminary database of LIBS and ATR-FTIR spectra in order to supply both elemental and molecular information, respectively.     

草酸铕颗粒微米层状颗粒的合成及其光学性能

在室温条件下, 以柠檬酸钠为辅助剂, 通过简单沉淀法合成了草酸铕Eu₂(C₂O₄)₃·10H₂O微米层状颗粒. 应用X射线衍射、X射线电子能谱、场发射扫描电子显微镜、光致发光光谱对Eu₂(C₂O₄)₃·10H₂O结构与性能进行了表征. 讨论了草酸铕微米层状颗粒可能的形成机理.