铝热反应法制备双股类螺旋Zn2SnO4单晶纳米带

This paper reports the preparation in large quantity of bifilar helix-like nanobelts of single crystal ine Zn2SnO4, a face-centered cubic spinel and transparent semiconductor that possesses wide applications in photovoltaic devices and sensors for humidity and combustible gases, by using a unique approach that combines chemical vapor deposition, aluminothermal reaction, vapor-liquid-solid growth, mergence of polar planes, and kinetic control by steady-state turbulent flow. The bifilar helix-like nanobelt was formed by the twisting and merging of two independent Zn2SnO4 nanobelts, as analyzed by scanning electron microscopy, transmission electron microscopy, electron diffraction, X-ray diffraction, Raman spectroscopy, and photoluminescence. It had a periodicity along the axial direction and hence, is actual y a super-lattice material. The photoluminescence measurements showed a strong light emission at 326.1 nm from the as-prepared sample with a line width of about 1.5 nm. The combined approach used in this study, in particular its aluminothermal reaction and steady-state turbulent gas flow perturbation steps, may be helpful in preparing other similar materials.     

SnO2纳米粒子的制备与表面改性

以SnCl4·5H2O和氨水为原料,用水热法制备了粒度均匀的SnO2纳米粒子,并用γ-氨丙基三乙氧基硅烷(KH-550)对其进行了表面改性. 用X射线衍射(XRD)、透射电子显微镜(TEM)、纳米粒度/Zeta电位测定和元素分析测试技术对粒子进行了表征. 研究结果表明,所制得的SnO2纳米粒子为四方晶系金红石型结构,改性后的纳米粒子均一性进一步提高,粒径分布在8～20 nm,能形成稳定的分散体系.     

水热法制备SnO2/α-Fe2O3纳米复合材料

用α-Fe2O3纳米粒子作为前驱物,以SnC l4和NaOH作为反应试剂,通过简单的水热法制备了SnO2/α-Fe2O3纳米复合材料。SnO2/α-Fe2O3纳米复合材料具有有趣的形貌:直径约为20nm的SnO2纳米棒以α-Fe2O3纳米粒子为中心向四周辐射生长。利用X-ray粉末衍射(XRD),透射电镜(TEM)和扫描电镜(SEM)等测试手段对样品的成份、结构、形貌和尺寸进行了表征,初步探讨了SnO2/α-Fe2O3纳米复合材料的形成机理。     

微波水热合成Zn2GeO4纳米带及其光催化活性

采用微波水热法快速合成Zn₂GeO₄纳米带, 研究反应温度、模板剂、原料用量等因素对晶体生长的影响, 并优化其合成条件. 用场发射扫描电镜(FE-SEM)、X射线衍射(XRD)光谱和紫外-可见漫反射吸收光谱(UV-Vis RDS)等手段分析产物的形貌、结构和组成, 考察合成的Zn₂GeO₄在甲基橙光催化降解反应中的性能. 研究结果表明: 微波水热条件下, 以摩尔比为2:1的乙酸锌和氧化锗为原料, 在160℃反应20 min可合成分散均匀的Zn₂GeO₄纳米带, 宽约100 nm, 长为几十微米. 与常规水热法相比,微波水热法合成的Zn₂GeO₄纳米带的本征缺陷减少, 光致发光(PL) 光谱降低,比表面积增大50.7%,光催化活性提高54.7%.     

不同形态SnO2纳米晶的制备

In this paper, we report our research on morphologically selective synthesis of nanocrystalline SnO2 by the combination of hydrothermal preparation and calcinated process. We firstly prepared SnO2 nanocrystals by the hydrothermal method at 140 ℃ for 3 h, using SnCI4 as the reactant. With the initial pH of 1.8 or 1.34, we prepared uniform and well-dispersed SnO2(tetragonal) nanocrystals, with similar size of about 3 nm, as determined by TEM. However, after being calcinated at 500 ℃ for 2 h, specimen 1 prepared at pH＝1.8 showed the rod-like shape with an average size of 5 nm×20 nm, while the other one(specimen 2)prepaed at pH＝1.34 showed a granular shape with an average size of 10 nm. XRD experiments showed that specimen 1 had a new diffraction peak after calcination, which was contributed by the (023) face of orthorhombic SnO2. The experiment results indicated that the morpholgy of SnO2 nanocrystals after calcination was closely related to the initial acidity of the reaction solution, possibly due to the difference in surface properties, e.g. the difference in crystalline faces exposed to the surface of particals, under different hydrothermal conditions.     

在乙二醇溶液中原位法制备纳米SnO2

乙二醇;锡配合物;溶胶 凝胶;纳米SnO2     

Zn_2SnO_4纳米材料制备及光致发光特性

以ZnO、SnO2和活性炭的混合物为原料,通过碳热还原热蒸发法无催化剂成功制备出Zn2SnO4纳米材料.借助X射线衍射仪(XRD)、拉曼光谱和扫描电子显微镜(SEM)对样品物相和形貌进行了表征,结果显示样品为面心立方结构的Zn2SnO4纳米链状棒,同时含有少量的ZnO物相.利用X射线光电子能谱(XPS)对Zn2SnO4样品表面各元素的化学状态及相互作用方式进行了测试,结果表明:样品中Zn和Sn分别是以+2价和+4价氧化态形式存在,其中Zn2p3/2电子有两个结合能,分别来自ZnO和Zn2SnO4,Zn2SnO4中Sn4+占据不同的格点位置.室温下光致发光谱(PL)结果显示,样品在紫外区域(320-450nm)和可见区域存在很强的发光带,其中紫外区域的宽发光带,经过高斯拟合可分为358和385nm两个发光峰,与同条件下制备得到的纯ZnO纳米材料发光谱比较,确认358nm发光峰是来自于Zn2SnO4的近带边复合发光.     

均匀沉淀法制备纳米氧化锡粒子

以 CO(NH2 ) 2 、Sn Cl4· 5 H2 O为原料 ,采用均匀沉淀法制备了纳米 Sn O2 粒子。以 TG-DTA、XRD、TEM等测试手段 ,对纳米 Sn O2 的粒子结构和形貌进行了研究。结果表明 ,在 6 0 0℃下热处理得到的粒子结晶性能良好。改变反应条件 ,制备出了粒径分布窄、分散性良好的纳米 Sn O2 粒子 ,其平均粒径为 15 nm。同时对均匀沉淀法形成纳米 Sn O2 粒子的机理进行了初步探讨     

纳米SnO2@TiO2的制备及其光催化性能

以SnCl4和Ti(OBu)4为原料,采用活性层包覆法制备了SnO2@TiO2包覆型复合光催化剂,并用XPS、IR、XRD、TEM和BET等手段进行了表征,以二甲基二氯乙烯基磷酸酯（简称DDVP）稀释液为模拟废水,考察了SnO2@TiO2的光催化活性及降解液初始浓度对反应动力学的影响.结果表明：包覆粒子由锐钛矿型TiO2和金红石型SnO2组成;与纯SnO2、TiO2相比,SnO2@TiO2包覆粒子的光催化活性明显提高,DDVP稀释液被光催化降解属于零级反应,但反应表观速率常数与降解液初始浓度成正比.     

SnO2纳米薄膜的制备、显微结构及气敏性能

SnO2纳米薄膜的制备、显微结构及气敏性能;SnO2薄膜;溶胶-凝胶法     

Hydrothermal synthesis, characterization, and photocatalytic properties of Zn2SnO4

Nanosized Zn₂SnO₄ (ZTO) particles were successfully synthesized by a simple hydrothermal process in water/ethylene glycol mixed solution using amines (ethylamine, n-butylamine, n-hexylamine, and n-octylamine) as mineralizer. The products were characterized by X-ray diffractions (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N₂ adsorption. The results indicated that the hydrothermal conditions, such as alkaline concentration (n-butylamine), reaction temperature, solvent composition, and the kind of amines, had an important influence on the composition, crystallinity, and morphology of the product. The as-synthesized ZTO samples exhibited high activities and durabilities for photodegradation of methyl orange and the activities were mainly affected by the crystallinities of the samples. A hexagonal-shaped ZTO (H-ZTO) sample was prepared in 0.53 M of n-butylamine solution at 180 °C for 20 h and its optical properties were characterized by UV-Vis diffuse reflectance and Photoluminescence (PL) spectra. Furthermore, the photocatalytic H₂ evolution reaction from ethanol aqueous solution over H-ZTO was also investigated.     

纳米片组装的Zn_2SnO_4空心八面体分级结构的制备与发光性能(英文)

以乙酸锌、四氯化锡、氢氧化钠为原料,在200℃用L-赖氨酸辅助合成纳米片组装的锡酸锌(Zn2SnO4)空心八面体分级结构。采用XRD、FESEM、TEM、HRTEM等对样品进行了表征,结果表明产物为立方相的Zn2SnO4,单个八面体的棱长在1～2μm,并且表面以及棱上长有许多尺寸在200～400nm的纳米片。此外,结果还表明,氢氧化钠和L-赖氨酸的加入量对八面体形状的形成起到了决定性的作用。产物的室温光致发光谱图说明所制备的产物在500～600nm有很强的发光性能。     

MnO_2/NiCo_2O_4的静电自组装合成及其电化学性能

通过带负电荷的MnO2纳米片与带正电荷的Co-Ni层状双氢氧化物(LDHs)纳米片的静电自组装外加后续热处理合成了异质层状结构的MnO2/NiCo2O4复合物.采用X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱、拉曼光谱、原子吸收光谱(AAS)、场发射扫描电镜(FESEM)和透射电子显微镜(TEM)对其结构和形貌进行了表征.用循环伏安(CV)、恒流充放电和电化学交流阻抗技术对其电化学性能进行了测试.研究结果表明,该方法制得的异质复合物具有多孔层状堆垛结构,这种特殊的结构不仅增大了电解液离子的接触面积,而且还为其嵌入-脱出提供了有效途径.该复合物在1 A·g-1电流密度时,-0.6-0.45 V电位窗口内的比电容达482 F·g-1,优于纯组分MnO2和NiCo2O4的电容性能.     

Al(2Pu)+H2(X1Σ+g)的分子反应动力学

基于多体展式方法所导出的ＡｌＨ２（Ｘ＾２Ａ１）分析势能函数,用准经典的Ｍｏｎｔｅ－Ｃａｒｌｏ轨迹法对Ａｌ（＾２Ｐｕ）＋Ｈ２（Ｘ＾１∑＾＋ｇ,ｕ＝ｊ＝０）的分子反应动力学过程进行了计算。结果表明,此反应的主产物为交换反应Ａｌ（＾２Ｐｕ）＋Ｈ２（Ｘ＾１∑＾＋ｇ,ｖ＝ｊ＝０）→ＡｌＨ（Ｘ＾１∑＾＋,Ｖ’,ｊ’）＋Ｈ（＾２Ｓｇ）的ＡｌＨ（Ｘ＾１∑＾＋,ｖ’,ｊ’）没有发现ＡｌＨ２（Ｘ＾２Ａ１）的络合物。而     

利用H2与金属氧化物的选择性反应从CO中除H2

研究了一些氧化物的H2－TPR及CO－TPR行为,结果发现,Co3O4／Al2O3,NiO／SiO2,NiO和Pd／NiO的H2－TPR温度要低于它们的CO－TPR温度,特别是Pd／NiO样品,它的H2－TPR温度为598K,而其CO－TPR温度高达949K,差别为351K,因此有可能利用Pd／NiO在一定温度下选择性地与CO中的H2反应而将其除去. 实验结果表明,Pd／NiO可在603K及4000h-1的条件下从H2（0.34％）,CO（50％）和N2（余）的混合气中选择性地除去90％以上的H2,吸氢容量为每克样品55mL标准态H2.     

C2H3自由基与O2反应的红外发射光谱及反应通道

The reaction of vinyl radicals with oxygen was investigated by Time-Resolved Fourier Transform infrared emission spectroscopy. The radicals were produced by the pulsed laser photolysis of C_2H_3Br at 248 nm. Vibrationally excited products of H_2CO(v1), HCO(v3), CO_2(v3, v), CH_3(v3), C_2H_2(v3), HO_2(v1), C_2H_2O_2(v3+v11), CO(v) formed in the C2H3+O_2 reaction have been observed. Four elementary reaction channels have been verified.     

Ni/NiCo2O4电极的制备及其析氧反应性能

采用溶胶-凝胶法制备NiCo₂O₄尖晶石粉体, 然后以多孔Ni 为基体, 通过复合溶胶涂覆结合烧结制备Ni/NiCo₂O₄ 涂层电极. 运用扫描电子显微镜(SEM)、能量色散谱(EDS)和X 射线衍射(XRD)表征粉体以及Ni/NiCo₂O₄涂层电极的组成和结构. 采用循环伏安(CV), 稳态极化(LSV), 电化学阻抗谱(EIS), 恒电位阶跃以及恒电位长时间电解研究涂层电极在5 mol·L^-1 KOH溶液中的电催化析氧反应(OER). 结果表明: Ni/NiCo₂O₄涂层电极与多孔Ni 电极对比, 具有低的析氧过电位、高的比表面积和高的稳定性能; 其中比表面积增大了28.69倍,表观活化能在不同过电位分别降低了166.78和162.15 kJ·mol^-1.     

ABO2型复合氧化物上CO-NO的反应性能

以柠檬酸络合法制备了CuCrO2、CuAlO2和CuFeO2等具有铜铁矿结构的ABO2型复合氧化物,并考察了它们在氧化和还原气氛中对CO NO反应的影响. CuAlO2和CuCrO2具有好的催化活性, CuCrO2更具有相当的稳定性,经过氧化和还原条件下的CO NO反应后,体相组成仍然保持不变. CuAlO2在还原条件下,部分被还原生成了零价铜. CuFeO2的催化活性和稳定性较差,在还原气氛中催化CO NO反应过程中,样品被还原,完全转化成了Cu0和CuFe2O4.     

TiO2/SnO2复合光催化剂的耦合效应

采用改进的sol gel技术制备TiO2/SnO2耦合型半导体光催化剂,利用XRD、气相色谱 仪、粒度仪和表面光电压装置等研究了耦合型半导体光催化机理和光催化效率的影响因素, 并通过降解甲醛探讨其在空气污染治理中的作用.实验结果表明,添加20 ％(mol) SnO2的复 合半导体光催化剂,其光催化效率比纯TiO2高一倍以上.据实验结果和粒子紧密堆积原理,提 出强耦合效应和弱耦合效应的光催化反应模型,并用此模型较好地解释了TiO2/SnO2复合型半 导体光催化剂的光催化效率随SnO2含量变化规律.