L-半胱氨酸自组装膜诱导草酸钙结晶研究

在CaCl2.H2O和Na2C2O4配制的过饱和溶液中,利用L-半胱氨酸(L-Cys)在金片上形成的自组装膜为模板,研究了草酸钙(CaOxa)在自组装膜上的结晶行为,并探讨了溶液pH对CaOxa晶体组成、晶型及其形貌的影响。采用X射线衍射(XRD)和扫描电子显微镜(SEM)等技术对CaOxa晶体的结构和形貌进行了表征。实验结果表明:当溶液pH=3.0时,溶液中可以形成一水草酸钙(CaC2O4.H2O,COM)和二水草酸钙(CaC2O4.2H2O,COD)晶体,而在同样pH条件下,在L-Cys自组装膜上只形成COD晶体,表明自组装单层对CaOxa晶体的成核和生长有重要影响。通过改变溶液的pH,在自组装单层上可以得到不同晶型和不同形状的CaOxa晶体。当pH=3.0时得到四方块状的COD晶体,而pH=5.0和pH=7.0时分别得到六边形和拉长六边形的COM晶体。     

EDTA辅助水热法合成硫化铋晶体

以Bi(NO3)3·5H2O和Na2S2O3·5H2O为原料,用乙二胺四乙酸(EDTA)辅助水热法合成了纳米或微米级的Bi2S3晶体(1),其结构、形貌和光谱性能经XRD,FE-SEM和UV-Vis表征。结果表明:溶液的pH对1的形貌有显著的影响,随着pH的增大,1由纳米棒组成的微米球逐渐转变为微米级片状结构;1出现蓝移。     

S/Cd物质的量比对微波水热制备CdS微晶的形貌影响及光学性能研究

采用微波水热法,以CdCl2·H2O和Na2S2O3·5H2O为镉源和硫源,在不同的S/Cd物质的量比条件下合成了CdS微晶。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、场发射扫描电子显微镜(FE-SEM)、EDS、透射电子显微镜(TEM)等对样品的物相、形貌和元素组分进行了分析。结果表明:随着S/Cd物质的量比的增大,产物CdS的形貌发生规律性变化,由四面体结构逐渐转变为准球形结构;准球形结构具有分级结构,是由更小的纳米晶组装而成;光致发光性质研究结果表明,所得的CdS微晶具有较好的蓝光发射性能。     

液-液界面法制备的Cu2O/GO复合材料及其光催化性能研究

采用液-液界面反应法制备了氧化亚铜/氧化石墨烯复合材料(Cu_2O/GO),采用X射线衍射分析仪、扫描电子显微镜对材料的物相和形貌进行表征,研究了其对亚甲基蓝(MB)的光催化降解效果。结果表明,利用液-液界面法制备的Cu_2O/GO材料中的Cu_2O呈多面体晶型结构,且均匀地分布在薄层氧化石墨烯两侧。在室温条件下,MB初始浓度为40mg·L~(-1),催化剂投加量为0.03g,降解时间为50min,溶液pH=7时,MB的降解率可达95%。     

凹心立方状Ca[Sn(OH)_6]微晶水热法制备与表征

采用Sn Cl4·5H2O、Ca Cl2·2H2O、Na OH为原料,表面活性剂PVP作为软模板,通过一个简单的水热过程合成出具有凹心立方形貌的Ca[Sn(OH)6]微晶。样品的XRD和TEM表征结果表明水热温度、水热时间、不同的碱源和表面活性剂对产物的形貌和尺度有一定的影响。初步讨论了凹心立方形貌的Ca[Sn(OH)6]微晶可能的形成机理。     

基于[P_2W_(15)O_(56)]~(12-)构筑块的四核铜夹心型化合物的合成、结构表征及其热稳定性

以三缺位型Dawson结构的钨磷酸盐前驱体Na12[α-P2W15O56]·24H2O与CuCl2·6H2O和Na3PO4为原料、水为溶剂,经溶液合成法合成了四核夹心型多金属氧酸盐化合物Na3H13[Cu4(H2O)2(P2W15O56)2]·72H2O(1);利用X射线单晶衍射仪、红外光谱仪、紫外光谱仪、X射线粉末衍射仪等分析了合成产物的结构,采用变温红外光谱测定了其热性质.结果表明,该化合物为三斜晶系,P-1空间群;其晶胞参数为:a=1.318 1(2)nm,b=1.345 1(2)nm,c=2.497 3(4)nm,α=78.149(3)°,β=88.242(3)°,γ=62.087(2)°.该化合物的骨架结构由两个三缺位的Dawson结构单元{P2W15O56}通过一个{Cu4O16}簇连接而成;其在350℃以下表现出一定的热稳定性.     

水热-热解法制备具有一维结构的Co3O4多晶

采用温和的水热-热解法, 在一定温度下, 通过调节Na2CO3溶液和可溶性钴盐的摩尔比控制产物的形貌, 得到具有一维结构的水热产物. 以该产物为前驱体制备了具有一维结构的Co3O4多晶. 以六次甲基四胺、尿素等代替Na2CO3溶液作为沉淀剂, 均得到了一维纳米结构的Co3O4, 表明CO2-3在水镁石CoO2层间的嵌入是得到一维结构水热产物的关键.     

pH值对溶剂热合成FeS2粉体的影响

采用FeSO₄与NH₂CSNH₂为反应前驱物, 通过溶剂热反应合成了高纯度的FeS₂ (pyrite)粉体. 实验表明,在聚乙烯吡咯烷酮（PVP）作保护剂的乙醇水溶液中, 200 ℃下反应36 h, 适当调节溶液的pH值, 即可在酸性环境(pH=5)和碱性环境(pH=10)下制得单一相的黄铁矿型FeS₂粉体. 讨论了溶液pH值对溶剂热合成FeS₂粉体物相组成、晶粒度及光学性质的影响.     

A型分子筛的合成及其对镉离子的吸附性能

以廉价的低品位铝矾土为原料,以偏铝酸钠为补充铝源,以碳酸钠为活化剂,采用碱熔融-水热法合成了A型分子筛,考察了水热条件对所制分子筛的影响,发现SiO2/Al2O3,Na2O/SiO2和H2O/Na2O摩尔比及反应时间是影响产物晶型的主要因素,其最佳合成工艺条件是:反应物配比为1.5Na2O:0.5Al2O3:1SiO2:128H2O,于90oC晶化12h.另外,研究了水溶液中Cd2+离子在该分子筛上的吸附行为,考察了吸附时间、Cd2+离子浓度、溶液初始pH值以及分子筛用量对吸附行为的影响.结果表明,A型分子筛对水中Cd2+离子吸附90min时达平衡,吸附过程符合准二级动力学速率方程;溶液初始pH=6时,Cd2+离子的去除率最高,吸附等温线可以用Langmuir和Freundlich模型来描述,最大吸附容量可达161.3mg/g,最佳吸附剂用量为1.00g/L.     

改良拜耳法制备超细片状α-Al2O3

为对冶金级氧化铝生产工艺进行优化,采用改良拜耳法生产利润更高的片状α-Al2O3。讨论分析了铝酸钠溶液除杂、球形晶种强化碳分聚附、水热深度脱钠及在添加AlF3晶种条件下煅烧对制备片状α-Al2O3的影响。通过XRF、XRD和SEM对产物的成分、物相及形貌进行了分析,结果表明:除杂过程中工业氢氧化铝、氧化钙、草酸钠添加量分别为45、10、10g/L时杂质铁、硅、镁、锌、钙的含量分别降至15、50、18、15、5.2 ppm;强化碳分聚附中添加少量的球形晶种,溶液的分解率达到92%以上,产物粒度降低且分布均匀;水热深度脱钠中降低pH促进三水铝石向一水软铝石转化的过程更加彻底,且在pH=1时Na2O含量低至0.0163%;在850℃下对洗涤后的水热产物煅烧4h,当AlF3晶种添加量为2%,可得纯度大于99.96%,形貌规则的超细片状α-Al2O3。     

Formation of α-Fe2O3/FeOOH nanostructures with various morphologies by a hydrothermal route and their photocatalytic properties

A series of α-Fe₂O₃/FeOOH nanostructures with different morphologies have successfully been synthesized based on K₄[Fe(CN)₆] at 140 °C by a novel hydrothermal method. The morphology and phase of α-Fe₂O₃/FeOOH can be controlled by adjusting the reaction time. UV–vis absorption spectrum, X-ray powder diffraction, and transmission electron microscopy analyses were used to characterize the resulting products. A detailed, rational mechanism is proposed for the formation of α-Fe₂O₃/FeOOH nanostructures. The potential applications of the as-synthesized α-Fe₂O₃/FeOOH nanoparticles with different morphologies on photocatalytic decomposition of salicylic acid were also investigated.     

前处理时间对Co3O4形貌及光催化性能的影响

以CoCl₂、Na₂CO₃为原料, 以油酸钠(SOA)为表面活性剂, 采用水热-热分解法合成了纯相尖晶石结构的Co₃O₄粉体。利用TG-DTA, XRD和SEM等手段跟踪反应过程, 研究了不同水热时间对产物形貌和结构的影响, 并根据实验结果分析了可能的反应机理及结构对光催化性能的影响。实验结果表明:制备前驱体的水热时间是影响产物形貌的关键因素, 并且终产物的结构形貌很大程度上决定了其光催化性能。     

前处理时间对Co_3O_4形貌及光催化性能的影响

以Co Cl2、Na2CO3为原料,以油酸钠(SOA)为表面活性剂,采用水热-热分解法合成了纯相尖晶石结构的Co3O4粉体。利用TG-DTA、XRD和SEM等手段跟踪反应过程,研究了不同水热时间对产物形貌和结构的影响,并根据实验结果分析了可能的反应机理及结构对光催化性能的影响。实验结果表明:制备前驱体的水热时间是影响产物形貌的关键因素,并且终产物的结构形貌很大程度上决定了其光催化性能。     

草酸沉淀法合成自组装纳米Co_3O_4及性质

<正>一维纳米材料具有高比表面积,表现出很多奇特的物理和化学性能,因此一维纳米材料的合成和性质引起了人们的广泛关注。目前,合成一维纳米氧化物的方法很多,如模板法合成一维纳米铁氧体、水热法合成γ-MnOOH纳米棒、静电纺丝法合     

Fabrication of Mesoporous CoS2 Nanotube Arrays as the Counter Electrodes of Dye‐Sensitized Solar Cells

Mesoporous cobalt sulfide nanotube arrays on FTO‐coated glass were synthesized by combining three simple technologies: the selective etching of ZnO sacrificial templates, mesoporous Co₃O₄ formation from cobalt‐chelated chitosan, and ion‐exchange reaction (IER). The mesoporous Co₃O₄ nanotubes composed of the Co₃O₄ nanoparticles possess a high surface area and are taken advantage for further removal of templates and IER. The morphologies and crystal structures of the CoS₂ nanotube arrays were characterized by SEM, TEM, and XRD analyses. Their electrocatalytic properties were determined by electrochemical analyses including cyclic voltammetry measurements and Tafel polarization. The DSSCs assembled with a CoS₂ counter electrode achieved a power conversion efficiency of 6.13 %, which was comparable to that of the DSSC with the Pt counter electrode (6.04 %). This indicates that the mesoporous CoS₂ nanotube array can be a low‐cost and efficient alternative for the reduction of electrolytes in DSSCs.     

Micro-sized Sb2O3 octahedra fabricated via a PEG-1000 polymer-assisted hydrothermal route

The micro-sized Sb₂O₃ octahedra can be synthesized on a large scale via a simple PEG-1000 polymer-assisted hydrothermal route (PAHR) in the temperature range of 160-180 °C for 10-14 h. The structures, compositions, and morphologies of the as-synthesized products are derived from X-ray power diffraction pattern, X-ray photoelectron spectra, and field emission scanning electronic microscope. Meanwhile, the optical properties of the micro-sized Sb₂O₃ octahedra are studied by their photoluminescene spectroscopy and Raman spectrum. Furthermore, the possible growth mechanism of the micro-metered Sb₂O₃ octahedra is discussed on the basis of a series of supplementary experiments. And it has been found that PEG-1000, sodium tartrate, the reaction temperature, and the reaction time have considerable effects on the final morphology of Sb₂O₃, while the pH value has an influence on the formation of the Sb₂O₃ crystals.     

沉淀法制备不同形貌和结构的纳米BiVO4

采用液相沉淀法，通过选择不同起始原料并控制反应温度和pH值，制备得到不同形貌和结构的纳米BiVO₄。采用X-射线衍射(XRD)、透射电子显微镜(TEM)和紫外-可见吸收光谱(UV-Vis)技术对产物进行分析表征。结果表明，采用NH₄VO₃作V源，室温下可直接制备得到结晶好的四方晶系硅酸锆型BiVO₄球形纳米颗粒，提高反应液pH值或升高温度，可得到单斜晶系白钨矿型BiVO₄，采用NaVO₃作为V源，室温下可直接得到单斜晶系白钨矿型片状BiVO₄。加入不同类型表面活性剂则得到不同形貌的BiVO₄。     

Synthesis and characterization of cobalt sulfide nanocrystals in the presence of thioglycolic acid via a simple hydrothermal method

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.     

Effects of PAA additive and temperature on morphology of calcium carbonate particles

Calcium carbonate particles with various shapes were prepared by the reaction of sodium carbonate with calcium chloride in the absence and presence of a polyacrylic acid (PAA) at 25°C and 80°C, respectively. The as-prepared products were characterized with scanning electron microscopy and X-ray diffraction. The effects of pH, temperatures, aging time and concentration of PAA and CaCO₃ on the crystal form and morphologies of the as-prepared CaCO₃ were investigated. The results show that pH, temperatures, concentration of PAA and CaCO₃ are important parameters for the control of morphologies of CaCO₃. Various crystal morphologies of calcite, such as, plates, rhombohedras, rectangles, ellipsoids, cubes, etc. can be obtained depending on the experimental conditions. Especially, the monodispersed cubic calcite particles can be produced by PAA addition at 80°C. Moreover, higher temperature is beneficial to the formation of monodispersed cubic or rectangular calcite particles. This research may provide new insight into the control of morphologies of calcium carbonate and the biomimetic synthesis of novel inorganic materials.     

2,4-二羟基苯甲酸辅助合成不同形貌二氧化铈及其在NH3-SCR中的应用

使用2,4-二羟基苯甲酸（DHBA）辅助控制合成出具有不同形貌（棒状与片状）的碱式碳酸铈。在水热阶段,碱式碳酸铈的形貌可以通过DHBA的量进行调控。当DHBA为3.5 mmol时,得到棒状碱式碳酸铈,然而增加DHBA的量至5.0 mmol时,可形成片状碱式碳酸铈。棒状与片状fcc-CeO₂（面心立方二氧化铈）可成功地通过相应的焙烧处理获得。所得二氧化铈均有较大的比表面积（>60 m²·g^-1）,然而与片状二氧化铈相比,棒状二氧化铈有更高的氧化还原能力与更多的酸量。棒状二氧化铈用于NH₃-SCR时有着更好的催化活性。