片层结构纳米CuO的强碱水热合成与表征

以浓度为2～10 mol/L的NaOH溶液为溶剂,采用水热方法合成了片层结构的纳米CuO材料。XRD测试结果证明了在五个NaOH溶液浓度下制备的纳米CuO材料的晶型均呈现单斜晶相;TEM和SEM结果显示片层结构的纳米CuO材料厚度约为42 nm,长轴长在150～200 nm之间,短轴长在90～120 nm之间,形状随着NaOH浓度升高由不规则状向椭圆形转变;FT-IR谱中纳米CuO材料特征吸收峰位置发生了范围较大的红移或蓝移;UV-DRS谱中纳米CuO材料呈现出代表不同电子跃迁引起的四个吸收谱带区。     

乙醇/水混合溶剂热法制备不同形貌的CuO晶体

以Cu(NO3)2·3H2O为原料,加入NaOH或NaOH+Na2CO3水溶液沉淀剂,生成Cu(OH)2或Cu2(OH)2CO3沉淀作前驱物,采用乙醇/水混合溶剂热法制备CuO.用FT-IR、XRD、SEM等方法对产物进行了表征.研究了溶剂的组成、前驱物的种类等因素对产物形貌及生成速率的影响.实验结果显示:以Cu2(OH)2CO3作前驱物,溶剂组成为V(C2H5OH):V(H2O)=1:2、150 ℃处理12 h可得形状规整的片状CuO;而以Cu(OH)2作前驱物,在相同条件下处理所得产物形貌为纺锤形.     

工艺因素对α-Al2O3微滤膜纳米ZnO改性涂层显微结构的影响

以硝酸锌和尿素为原料,采用共沉淀法在α-Al2O3微滤膜孔内表面制备了纳米ZnO涂层.实验考察了反应物浓度、反应温度和反应时间对纳米ZnO涂层显微结构的影响规律,同时结合TEM对该涂层的显微结构进行观察分析.结果表明:当硝酸锌浓度为0.3 mol/L、尿素浓度为0.6 mol/L、反应温度为95 ℃、反应时间为4 h时,ZnO涂层的晶粒细小均匀、结构致密且表面具有良好的平整度.采用该ZnO涂层改性后的α-Al2O3微滤膜,其过滤效率得到了明显提高,水通量最大增幅达到45.6;.     

水热法合成碲化铋粉体及其热稳定特性

通过改变实验条件,在130 ～200℃、NaOH溶液浓度为2～8mol/L的较宽水热条件下合成出单相Bi2Te3粉体.利用X射线衍射(XRD),透射电镜(TEM),高分辨透射电镜(HRTEM),能谱色散仪(EDAX),热分析系统(TG-DTA)对产物的物相组成,形貌特征和晶体结构,热稳定性进行了研究.结果表明当不添加表面活性剂时,在一定反应温度下,NaOH溶液浓度不仅是合成纯Bi2Te3粉体的重要因素,而且影响所得Bi2Te3粉体的晶体形貌和晶粒尺寸.当NaOH溶液浓度较低、反应温度较高时,以原子结合方式生成Bi2Te3,反之,以离子结合方式生成Bi2Te3.一般形成机理的提出对今后采用水热法或溶剂热法合成碲化物有一定帮助,而热稳定性的研究对实验结果提出新的要求.     

均匀沉淀水热法微/纳米Sm2O3的合成与表征

以尿素为沉淀剂,采用均匀沉淀水热法,合成了微/纳米Sm2 O3及其前驱体.利用XRD、TG-DTA和扫描电子显微镜(SEM)等表征手段对产物进行测试与分析,确定前驱体的焙烧温度为800℃.考察了反应温度和硝酸钐浓度对微/纳米Sm2O3形貌、尺寸的影响,探讨了Sm2O3及其前驱体的形成过程,提出了不同形貌微/纳米Sm2O3可能的形成机理.结果表明,当反应温度分别为100℃、140℃和170℃时,微/纳米Sm2O3的形貌依次由球状变为树枝状再变为双扇状;当硝酸钐的浓度分别为0.4 mol/L、0.6 mol/L和0.8 mol/L时,球状微/纳米Sm2O3的尺寸依次为1.49 ～3.18 μm、1.32～2.59 μm和0.69～1.41 μm,且随硝酸钐的浓度的增大而减小.     

原位反应合成Ag/CuO复合材料中生成立方氧化铜的研究

本文通过对原位反应合成Ag/CuO复合材料中生成立方氧化铜的可能性进行了研究,对CuO和Ag/CuO分别进行热重-差热分析实验以及反应烧结实验.结果表明:原位反应合成法制备Ag/CuO复合材料中,生成立方氧化铜有三种方式:(1)Cu与O2直接反应合成立方CuO可能性小,或者不发生;(2)以Cu与O2反应合成单斜的CuO后,在后期烧结时发生相转变生成立方CuO为立方CuO的主要形成方式.实验也说明了1048 K(即775℃)左右的温度即是单斜CuO与立方CuO转变的温度;(3)通过实验与理论分析还发现,Ag的存在对形成立方CuO的相变以及形成量有一定的影响.     

水热条件下黄磷炉渣废料制备碳酸钙晶须

本文采用黄磷炉渣制备白炭黑后的残留废液为原料,尿素作为沉淀剂制备碳酸钙晶须,系统研究了晶型控制剂(MgCl2)的浓度、反应温度、反应时间、尿素和残留废液的体积比等因素对碳酸钙晶须形貌和物相组成的影响,所得产品通过X射线衍射、扫描电镜进行了分析与表征.研究结果表明,反应温度140℃,反应时间3 h,(NH2)2CO:CaCl2体积比为1:3,晶型控制剂为0.3 mol/L的条件之下,可获得平均长度在50 p.m,长径比为10左右的碳酸钙晶须.     

g-C3N4和CuO复合材料的制备、表征及光催化研究

高温煅烧三聚氰胺制备类石墨结构氮化碳(g-C3N4),然后以硝酸铜Cu(NO3)2和g-C3N4为原料,去离子水和无水乙醇作溶剂,在加入适量氨水的反应条件下通过水热法反应制备g-C3N4/CuO纳米复合材料.采用场发射扫描电子显微镜(FE-SEM)、光电子能谱仪(XPS)、紫外可见漫反射(UV-Vis-DRS)和荧光光谱(PL)等测试对复合材料进行表征.通过XRD、SEM和XPS测试结果可知微米球形CuO和g-C3N4紧密的结合起来,而由UV和PL谱图表明CuO和g-C3N4的复合扩展了材料对可见光的吸收范围和减慢了材料的光生电子和空穴的复合率.通过在可见光下降解甲基橙(MO)来检测复合材料的光催化活性,结果表明,在没有过氧化氢(H2O2)的体系下,经过4 h的光反应后,70-g-C3N4/CuO对MO的降解率达到了85;;但是在H2O2的体系下,经过1 h光反应后,70-g-C3N4/CuO对MO的降解率达到了96;.通过自由基的捕获实验说明羟基自由基、超氧自由基、空穴在降解MO过程中起到重要的作用.复合材料在经过四次的循环实验后,对MO的降解率基本能达到90;.因此,g-C3N4和CuO的复合抑制了电子-空穴的复合和扩展了吸收光波长范围,这样就使g-C3N4/CuO材料有了好的光催化性和稳定性.     

微波辅助法制备氧化铜非酶葡萄糖传感器

采用微波辅助法制备了氧化铜(CuO)材料,其结晶度好,没有杂质,呈现片层堆叠而成的块状结构.以CuO材料修饰玻碳电极作为工作电极(CuO/GCE),饱和甘汞电极作为参比电极,铂丝电极作为对电极,在碱性条件下对葡萄糖溶液进行电化学性能检测.该传感器对520 nM到2.0 mM浓度范围内的葡萄糖溶液实现了优良的检测性能,灵敏度为2491.362μA·cm-2·mM-1,检测限为216 nM(S/N=3),在2 s内就可以完成反应.丙烯酸等物质对传感器的影响可以忽略,具有良好的抗干扰性.     

原位反应合成Ag/CuO复合材料中生成立方氧化铜的研究（英文）

本文通过对原位反应合成Ag/CuO复合材料中生成立方氧化铜的可能性进行了研究,对CuO和Ag/CuO分别进行热重-差热分析实验以及反应烧结实验。结果表明:原位反应合成法制备Ag/CuO复合材料中,生成立方氧化铜有三种方式:(1)Cu与O_2直接反应合成立方CuO可能性小,或者不发生;(2)以Cu与O_2反应合成单斜的CuO后,在后期烧结时发生相转变生成立方CuO为立方CuO的主要形成方式。实验也说明了1048 K(即775℃)左右的温度即是单斜CuO与立方CuO转变的温度;(3)通过实验与理论分析还发现,Ag的存在对形成立方CuO的相变以及形成量有一定的影响。     

Synthesis and self‐assembled mechanism of CuO peony‐flowers by a composite hydroxide‐mediated approach at low temperature

A composite‐hydroxide mediated (CHM) method was utilized for the synthesis of CuO peony‐flower nanostructures under temperatures ranging between 25 and 160 °C. The CHM mechanism was confirmed through X‐ray Powder Diffraction (XRD) and a Thermo‐Gravimetric Differential Scanning Calorimeter (TG‐DSC). Cu(NO₃)₂ was shown to transform into Cu(OH)₂ in the mixed alkalis (NaOH/KOH); the reaction was facilitated by the solvent properties of the mixed alkalis. Cu(OH)₂ subsequently consumed H₂O in the adsorption of the mixed alkalis at 25∼65 °C. At higher reaction temperatures (>65 °C), the Cu(OH)₂ was seen to decompose at an accelerated rate. Therefore, crystalline CuO could be obtained not only above 65 °C but also at 25 °C. The crystal morphology and structure of CuO were examined through Filed Emission Scanning Electron Microscopy (FE‐SEM) and Transmission Electron Microscopy (TEM). It was determined that the CuO peony‐flower had a polycrystalline structure composed of single crystalline CuO petals. Using the Selected Area Electron Diffraction (SAED) results, the rings were indexed as (002), (111), (112), (202) and (−113), which was in agreement with the XRD results. With increasing temperature, the CuO flower petals self‐assembled through random aggregation and gathered CuO nanorod parts, which led to incomplete CuO flower petals through orientated aggregation. Prolonged reaction time led to the growth of CuO flower petals in the direction of [001]. An ideal CuO flower structure was observed through TEM observation.     

Facile synthesis and characterization of hierarchical CuO nanoarchitectures by a simple solution route

The controlled synthesis of hierarchical CuO nanomaterials in a solution phase has been realized with high yield at low temperature using copper acetate hydrate and NaOH as starting materials with the assistance of surfactant under hydrothermal conditions. X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ultraviolet‐visible spectroscopy (UV‐Vis) were used to characterize the products. It was shown that the hierarchical CuO nanoarchitectures were formed through aggregation of tiny single‐crystal CuO nanorods. Experiments demonstrated that the morphology of CuO products was significantly influenced by hydrothermal temperature and reaction time. A rational growth mechanism based on oriented attachment was proposed for the selective formation of the hierarchical CuO nanoarchitectures. Our work demonstrated the growth of hierarchical CuO nanoarchitectures built from one‐dimentional nanorods through a one‐step solution‐phase chemical route under controlled conditions. In addition, The UV‐Vis spectrum of the hierarchical CuO nanoarchitectures showed large blue shift because of the quantum size effect. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Precipitation of calcium carbonate particles by gas–liquid reaction: Morphology and size distribution of particles in Couette-Taylor and stirred tank reactors

The morphology and size of CaCO₃ precipitated by CO₂–Ca(OH)₂ reaction in stirred tank and Couette-Taylor reactors were experimentally investigated. The Taylor vortex in CT reactor encouraged more homogeneous mixing conditions, resulting in the production of smaller particles with a uniform shape throughout the reactor. However, in the stirred tank reactor, the local non-homogeneity of the mixing intensity led to the simultaneous production of cube-like and spindle-like particles at a high reactant concentration. The agglomeration of CaCO₃ resulted in a bimodal size distribution. However, the morphology and size of a single particle were predominantly changed by the excess species in the solution. The largest mean size and cube-like particles were observed under stoichiometric reaction conditions. As the excess species concentration increased, the morphology was transformed to a spindle-like shape and the mean size decreased due to selective adsorption of the excess species on the crystal faces.     

Fabrication and photocatalytic property of CuO nanosheets via a facile solution route

Two‐dimensional (2D) CuO nanosheets were fabricated on Cu foils using a solution method. The method was novel, easy and can be completed at room temperature in the absence of any surfactant. The obtained materials were characterized by X‐ray diffraction (XRD), X‐ray Photoelectron Spectroscopy (XPS), scanning electron microscopy (SEM) and ultraviolet‐visible (UV‐Vis) spectroscopy. The effects of reaction time and temperature on the morphology and formation of CuO nanosheets were investigated, and a possible mechanism for the formation of CuO nanosheets was proposed. Experiments demonstrated that the formation of CuO nanosheets were significantly influenced by the growth time, and the reaction temperature was a key factor in determining the size of CuO nanosheets. Photocatalytic performance of CuO nanosheets was evaluated by measuring the decomposition rate of methyl orange solution. About 93% of the methyl orange was degraded after 150 min, which was much more efficient than that of CuO nanoparticles.     

Preparation of CuO mesocrystals via antlerite intermediate for photocatalytic applications

CuO mesocrystals were synthesized by thermal decomposition of antlerite (Cu₃(OH)₄SO₄) formed as an intermediate by the reaction between CuSO₄.5H₂O and urea under specific experimental conditions. Antlerite possessing spindles of sea urchin‐like morphology was obtained via controlled hydrolysis process using ethylene glycol as a co‐solvent. Antlerite and CuO mesocrystals were characterized by X‐ray diffraction (XRD), fourier transform‐infrared spectrum (FT‐IR), thermo gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDS). A probable mechanism for formation of such morphologies has been proposed. The photocatalytic and optical properties of CuO mesocrystals were also evaluated.     

Leaf‐like copper oxide nanocrystals synthesized by a gas‐liquid diffusion method at room temperature

The leaf‐like copper oxide (CuO) nanocrystals have been synthesized by a gas‐liquid diffusion method in pure aqueous solution at room temperature. The structure, morphologies and related properties of the as‐prepared crystals were characterized with X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), selected area electron diffraction (SAED) and thermogravimetric analysis (TG). The influence of copper concentration was investigated, which plays an important role in the formation of nanostructured CuO crystals. Only when the copper concentration was low enough (0.005 M) that the leaf‐like CuO could be obtained directly. Additionally, a growth mechanism of CuO was also proposed based on the observed results.     

溶胶-凝胶法制备La2CuO4纳米晶生长动力学研究

以硝酸镧和硝酸铜为起始原料,柠檬酸为络合剂,乙二醇为交联剂,采用溶胶-凝胶法制备了La2CuO4纳米晶.通过XRD和FESEM对La2CuO4粉体进行了测试和表征,研究了不同柠檬酸配比对La2CuO4相组成、显微结构以及晶体生长活化能的影响.结果表明:当柠檬酸与金属阳离子总和(La3++Cu2+)的物质的量比为1∶1,600℃煅烧保温2h后,可获得单一正交晶型的La2CuO4,颗粒形貌为球状结构,平均尺寸为65 nm;在制备过程中提高柠檬酸的加入量,能够降低La2CuO4晶体的生长活化能,当物质的量比由0.5∶1增加至1∶1时,生长活化能由67.3 kJ/mol降低到50.5 kJ/mol.     

微波固相反应前驱体热分解法制备纳米氧化铜粉体

将固体CuSO4·5H2O和Na2CO3混合均匀后溶于适量乙醇中,然后进行微波辐照,立即反应生成泥浆状固体,将该泥浆状固体洗涤后干燥即可得到粉状前驱体.然后在600 ℃加热1 h分解该前驱体,即可制得纳米氧化铜粉体.在加热速率为10 ℃/min的条件下,对该前驱体进行表征,发现其热分解和晶体化温度约为550 ℃.对制得的纳米氧化铜粉体进行XRD、SEM、TEM和IR分析,结果表明制得的产物为纳米氧化铜粉体,其粉体粒径在30～50 nm,平均粒径约为40 nm.     

Facile solvothermal synthesis,growth mechanism and thermoelectric property of flower‐like Bi2Te3

Hierarchical flower‐like Bi₂Te₃ was synthesized through a facile solvothermal method. The crystal structure and morphology of the as‐prepared samples were characterized by X‐ray diffraction (XRD), filed emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and high resolution TEM. The reaction parameters such as reaction time, the amount of glucose, concentration of NaOH and the reaction temperature were systematically investigated. Based on the FESEM observations, a possible mechanism defined as a self‐assembly process accompanied by anisotropic growth mechanism was proposed. Moreover, the thermoelectric properties were measured at the temperature range of 300–600 K. The hierarchical flower‐like Bi₂Te₃ presented good thermoelectrical properties. The maximum ZT value reached up to 0.6 at 600 K, which was higher than that of Bi₂Te₃ nanoparticles.