水热法制备二氧化铈纳米空心球及其吸附性能研究

用六水硝酸铈(Ce(NO_3)_3·6H_2O)作为铈源,以聚乙烯吡咯烷酮(PVP)为表面活性剂,在乙二醇的水溶液中通过水热法制备了单分散、粒径较均一的CeO_2纳米空心球。利用傅立叶转换红外分析(FT-IR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)、X射线能谱(XPS)、N_2等温吸附-解吸及紫外-可见光谱(UV-Vis)来表征CeO_2纳米空心球并研究其吸附性能。结果表明,水热法制备的CeO_2空心球是由立方萤石结构的纳米颗粒组装成的介孔中空材料,孔径分布窄,尺寸约为3~5 nm,空心球的直径约为400 nm,壁厚30 nm左右,空心球的BET比表面积为76.86 m2·g-1。讨论了CeO_2空心球的制备机理,所制备的CeO_2空心球对重铬酸钾溶液的吸附率可达到70%,约为CeO_2粉末的3倍。     

CeO_2纳米空心球的制备与光催化性能研究

采用乳液聚合法制备了聚苯乙烯-丙烯酸微球(P(St-AA))为模板,通过无机物前驱体颗粒的自组装制备出CeO2/P(St-AA)复合微球,煅烧去除聚合物模板后,得到CeO2纳米空心球。通过扫描电子显微镜、透射电子显微镜、傅里叶红外光谱、X射线光电子能谱、X射线衍射和热重分析仪等测试手段对复合微球和CeO2纳米空心球的表面形貌和结构进行了表征。实验结果表明,CeO2空心球由面心立方相颗粒构成,内空心直径约为250nm,壳厚度约为20nm。CeO2纳米空心球对甲基蓝模拟染料废水具有良好的脱色能力,经4h处理后脱色率达到95%以上。     

非水溶剂溶胶-凝胶法制备纳米SnO2

以乙二醇为溶剂、SnCl4·5H2O为原料用溶胶凝胶法制备了SnO2粉体材料.用X射线衍射和透射电子显微镜对材料进行了检测和表征,所得SnO2粉末具有良好的分散性,最小晶粒粒径为9.5nm.探讨了初始反应物浓度和聚合温度对晶粒粒径的影响.     

氧化还原法制备SnO2纳米棒的研究

在聚氧乙烯五醚(NP5)、聚氧乙烯九醚(NP9)和环己烷组成的微乳体系中用氧化还原法制备SnO2前驱物,然后在熔盐中再经800℃、860℃焙烧2.5h,成功地制备了金红石结构的SnO2纳米棒,并用透射电子显微镜,X射线衍射对SnO2纳米棒的结构进行了表征.     

四氧化三铁亚微空心球的制备及表征

采用水热法制备出亚微尺寸Fe_3O_4空心球.用X射线衍射谱(XRD)和傅里叶红外光谱(FT-IR)表征了样品的相结构,用透射电子显微镜(TEM)和场发射扫描电子显微镜(FESEM)照片表征样品的形貌,表明在一定反应条件(反应温度、反应时间、反应试剂)下,反应产物可形成不同的形貌:针叶状的纳米颗粒、亚微尺寸的疏松球、实心球和空心球等.用振动样品磁强计(VSM)测量了样品的室温磁性,表明Fe_3O_4亚微空心球样品表现为铁磁性.     

以三聚氰胺-甲醛微球为模板制备均一氧化钆空心球

以三聚氰胺和甲醛在水溶液中缩聚交联生成的单分散三聚氰胺-甲醛(MF)微球为模板,以尿素为沉淀剂,用均相沉淀法制备出核壳结构前驱体MF/Gd(OH)CO_3复合微球,煅烧除去模板后得到单分散氧化钆(Gd_2O_3)空心球。使用傅立叶红外光谱(FT-IR)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)、X射线衍射分析(XRD)、X射线能谱仪(XPS)、热重分析(TG)和差示扫描量热分析(DSC)等手段表征了Gd_2O_3空心球的形貌和结构组成。结果表明,将前驱体煅烧去除了MF模板,非晶态的Gd(OH)CO_3发生热分解反应生成了纯立方晶相的Gd_2O_3空心球,其粒径约为2.4μm,壳层的厚度为120 nm。     

交流电沉积制备SnO2纳米线及其电沉积条件研究

采用阳极氧化的方法制备了孔径为30～50nm多孔阳极氧化铝(AAO)模板,用交流(AC)电沉积法在氧化铝模板孔洞内沉积金属锡,然后在空气中750℃加热含锡的模板10h,热氧化制备了直径在30～50nm SnO2纳米线．用扫描电子显微镜,透射电子显微镜,X射线衍射仪对所制备的SnO2纳米线进行了表征,表明所制备的纳米线为多晶结构．并通过改变交流电沉积过程中的电压,频率和热氧化时间来考察不同沉积条件对沉积结果的影响,发现采用交流沉积制备金属纳米线的过程中,频率和电压是影响沉积结果的关键因素．     

SnO/Sn_3O_4异质结构的制备及其光催化性能

采用简单的一步水热法合成了SnO/Sn_3O_4异质结构花状微球。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)、表面积分析仪和紫外-可见吸收光谱(UV-Vis)等测试手段对其形貌、结构、比表面积和光学性质进行了分析,并以罗丹明B(RhB)为模型污染物研究了样品的光催化性能。结果表明,花状微球由大量SnO/Sn_3O_4异质结构组成,比表面积为52.6 m2/g;样品中SnO和Sn_3O_4的禁带宽度分别为2.90和2.51eV,同时对罗丹明B有较好的光催化降解特性。     

硫掺杂TiO_2空心球制备及光催化性能研究

以聚苯乙烯-丙烯酸羟乙酯共聚(P(StHEA))微球为模板、钛酸四丁酯和硫脲为主要原料,制备了硫掺杂二氧化钛(S-TiO2)空心球,采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)和X光电子能谱(XPS)表征产物的形貌、晶型以及硫元素的掺杂状态,并以甲醛溶液模拟废水,研究了S-TiO2空心球的紫外光催化性能。结果表明,煅烧去除了P(St-HEA)微球模板,成功得到TiO2空心球,硫元素掺杂对TiO2空心球的粒径和形貌影响不大。STiO2空心球锐钛矿型晶粒的尺寸缩小,晶型由纯的锐钛矿型转化为锐钛矿/金红石型混合晶型。硫脲引入的硫离子,以S4+状态取代TiO2晶粒中的Ti4+离子,形成Ti1-xSxO2固溶体。S-TiO2空心球光催化性能优于TiO2空心球,且空心球的光催化性能优于粉体P25。STiO2空心球在紫外光下照射2 h,降解甲醛的催化效率为60%。     

SiO2空心球的制备与表面形貌调控

以聚苯乙烯(PS)微球为模板,通过水解正硅酸乙酯来包裹PS微球,制备了PS/SiO_2核壳结构微球,然后通过高温煅烧得到SiO_2空心球。利用纳米粒度仪、扫描电子显微镜、透射电子显微镜分析SiO_2空心球的粒径和表面形貌。采用控制变量法分别研究了PS微球表面电荷、pH、水和正硅酸乙酯的用量对SiO_2空心球表面形貌的影响。实验证明,以表面带正电荷的PS微球为模板,反应体系pH=11.0,正硅酸乙酯注入速度为100μL/min时,制备的SiO_2空心球表面最光滑。     

SnO2/Fe2O3双层薄膜的界面结构及其对气敏特性的影响

本文给出用等离子化学气相沉积 (PCVD)技术制备的SnO2 /Fe2 O3 双层薄膜结构的俄歇谱 (AES)剖面分析、透射电镜 (TEM)断面形貌和扫描电镜 (SEM)表面形貌的实验研究结果。AES剖面分析和TEM断面形貌图显示在SnO2 与Fe2 O3 界面区有一个约 35nm厚的过渡层存在 ,其质地松散。实验还发现这个界面过渡层的存在缓解了层间应力 ,增强了SnO2 薄膜的附着力 ,对该双层膜的气敏特性有明显的控制作用 ;但当SnO2 层厚大于 2 70nm时 ,其控制作用几乎完全消失     

Preparation of SnO2 nanoparticles by hard template method for high selectivity gas sensors

In this paper, SnO2 nanoparticles were synthesized by the impregnation method with SnCl2 x 2H2O as the inorganic precursor and mesoporous silica MCM-41 as the hard template. The physical and chemical properties of the products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The SnO2 nanoparticles grew into the ordered channels of MCM-41. After removing the silica template, the products exhibited good rutile structure. The gas sensing properties of the SnO2 nanoparticles were also studied. The results indicated that these SnO2 nanoparticle sensors showed high selectivity towards ethanol.     

焙烧室温条件固相反应制备前驱物合成SnO2纳米棒的研究

室温条件下通过固相反应合成了SnO2纳米颗粒前驱物.在600～780℃对前驱物进行焙烧,在NaCl、KCl和KCl＋NaCl的熔盐介质中SnO2前驱物纳米颗粒自组装生长形成SnO2 纳米棒.利用TEM、XRD和XPS对SnO2纳米棒结构、形貌和成分进行了研究.结果表明SnO2纳米棒直径为20～80nm,长度从几百纳米到十几微米.分析了SnO2 纳米颗粒前驱体熔盐介质中的生长,利用固相转变生长可以解释SnO2纳米棒在熔盐介质中的生长机制.     

Rutile structured SnO2 nanowires synthesized with metal catalyst by thermal evaporation method

One-dimensional (1-D) nanostructures such as tubes, rods, wires, and belts have attracted considerable research activities owing to their strong application potential as components for nanosize electronic or optoelectronic devices utilizing superior optical and electrical properties. Characterizing the mechanical properties of nanostructure is of great importance for their applications in electronics, optoelectronics, sensors, actuators. Wide-bandgap SnO2 semiconducting material (Eg = 3.6 eV at room temperature) is one of the attractive candidates for optoelectronic devices operating at room temperature, gas sensors, and transparent conducting electrodes. The synthesis and gas sensing properties of semiconducting SnO2 nanomaterials have became one of important research issues since the first synthesis of SnO2 nanobelts. Considering the important application of SnO2 in sensors, these structures are not only ideal systems for fundamental understanding at the nanoscale level, but they also have potential applications as nanoscale sensors, resonator, and transducers. The structured SnO2 nanorods have been grown on silicon substrates with Au catalytic layer by thermal evporation process over 800 degrees C. The resulting sample is characterized and analyzed by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and energy-dispersive X-ray spectroscopy (EDS). The morphology and structural properties of SnO2 nanowires were measured by scanning electron microscopy and high-resolution transmission electron microscopy. The mean diameter of the SnO2 nanorods grown on Au coated silicon (100) substrate is approximately 80 nm. In addition, X-ray diffraction measurements show that SnO2 nanorods have a rutile structure. The formation of SnO2 nanowires has been attributed to the vapor-liquid-solid (VLS) growth mechanisms depending on the processing conditions. We investigated the growth behavior of the SnO2 nanowires by variation of the growth conditions such as gas partial pressure and temperature.     

SnO2纳米棒的制备及表征

在聚氧乙烯五醚（NP5），聚氧乙烯九醚（NP9），乳化剂（OP）和环己烷组成的微乳体系中制备二氧化锡前驱物。然后再经800－820℃熔烧2.5h，成功地制备了直径为30－90nm，长5－10μm的金红石结构的二氧化锡纳米棒，并用透射电子显微镜，电子衍射，X射线衍射对二氧化锡纳米棒的结构进行了表征。用熔盐合成机理对其形成进行了讨论，初步认为是成核、长大过程形成了二氧化锡纳米棒。     

Growth of tin dioxide nanobelts via Au-catalytic VLS process

Ultra-long (several millimeters) tin dioxide SnO2 nanobelts were prepared by chemical vapor deposition at 850 degrees C. The X-ray powder diffraction (XRD) indicated that the as-prepared sample is tetragonal phase SnO2; field emission scanning electron microscopy (FESEM) reveals the as-prepared SnO2 is uniform nanobelts; transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) studies show the nanobelts is monocrystalline with width of hundreds of nanometers and growth along [101] crystal direction; X-ray energy-dispersive spectrometer (EDS) and photoluminescence (PL) spectrum were used to detail its composition and optical properties. The possible formation mechanism of these ultra-long nanobelts was also proposed on the basis of experiments.     

Graphene-SnO(2) composites for highly efficient photocatalytic degradation of methylene blue under sunlight

Graphene sheets decorated with SnO(2) nanoparticles (RGO-SnO(2)) were prepared via a redox reaction between graphene oxide (GO) and SnCl(2). Graphene oxide (GO) was reduced to graphene (RGO) and Sn(2+) was oxidized to SnO(2) during the redox reaction, leading to a homogeneous distribution of SnO(2) nanoparticles on RGO sheets. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images show uniform distribution of the nanoparticles on the RGO surface and high-resolution transmission electron microscopy (HRTEM) shows an average particle size of 3-5?nm. The RGO-SnO(2) composite showed an enhanced photocatalytic degradation activity for the organic dye methylene blue under sunlight compared to bare SnO(2) nanoparticles. This result leads us to believe that the RGO-SnO(2) composite could be used in catalytic photodegradation of other organic dyes.     

Shape-controlled synthesis and properties of dandelion-like manganese sulfide hollow spheres

Dandelion-like gamma-manganese (II) sulfide (MnS) hollow spheres assembled with nanorods have been prepared via a hydrothermal process in the presence of l-cysteine and polyvinylpyrrolidone (PVP). l-cysteine was employed as not only sulfur source, but also coordinating reagent for the synthesis of dandelion-like MnS hollow spheres. The morphology, structure and properties of as-prepared products have been investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HRTEM) and photoluminescence spectra (PL). The probable formation mechanism of as-prepared MnS hollow spheres was discussed on the basis of the experimental results. This strategy may provide an effective method for the fabrication of other metal sulfides hollow spheres.     

空心柱状CuS的制备及其降解染料性能

以硝酸铜、硫代硫酸钠为原料,采用沉淀法制备空心柱状CuS。通过扫描电子显微镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)和傅里叶红外光谱测定仪(FT-IR)对所制备的空心柱状CuS的形貌及物相进行表征。同时,以甲基橙染料(MO)为目标污染物,研究空心柱状CuS的降解性能。结果表明:所制备的空心柱状CuS由CuS纳米片组装而成,其直径在400nm,长度为2.0μm左右。空心柱状CuS与H_2O_2组成的类芬顿体系对染料具有优异的降解能力,110min后甲基橙的降解率可高达86.6%,远优于实心结构CuS对染料的降解能力。     

一锅溶剂热法合成SnO2纳米球和纳米颗粒

用SnCl4·5H2O和乙二醇作为前驱体，采用一锅溶剂热法合成单分散SnO2纳米球和纳米颗粒，用X射线粉末衍射（XRD）、扫描电镜（SEM）、透射电镜（TEM）、傅立叶红外吸收光谱（VT—IR）和紫外吸收光谱等手段对产物的结构、形貌进行表征，考察了反应时间对SnO2的形貌特征的影响，XRD的结果表明，合成得到的SnO2为金红相的结构SnO2；SEM和TEM观察结果显示，SnO2的形貌随反应时间的改变而改变，随着反应时间的增加，SnO2最终从单分散纳米球变成纳米颗粒；在红外吸收光谱分析的基础上对溶剂热反应机理进行了讨论；紫外吸收光谱的谱图表明合成得到的SnO2有较好的光电性能。