仿生分级结构NiO纳米线/纳米纤维的可控制备及光催化性能

采用静电纺丝技术和"自下而上"的溶液相自组装技术, 制备了具有仿生主次分级结构的三维NiO纳米线/纳米纤维. 采用扫描电子显微镜(SEM)、 X射线衍射仪(XRD)和比表面积分析仪分别对其形貌、 晶型和孔结构进行了表征. 以水体中的有色染料亚甲基蓝为模型污染物, 研究了分级结构NiO纳米线/纳米纤维的光催化性能. 结果表明, 在180 min内, 以分级结构NiO为催化剂时, 亚甲基蓝的降解率达到了97%, 分别是以纳米纤维和纳米粒子为催化剂时的1.24倍和2.16倍.     

A facile synthesis of hierarchical flower-like TiO2 with enhanced photocatalytic activity

The hierarchical flower-like TiO₂ has been achieved by using a simple solvothermal process without any surfactants or colloidal crystals as a template. The structures of the products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption–desorption analysis. The relationship between hierarchical structure and photocatalytic performance has been presented based on detailed characterizations. It was found that the hierarchical flower-like structure was a benefit for light absorption and significantly enhanced the photocatalytic activity.     

Fabrication of NiO coated SiO2 and SiO2 coated NiO for the removal of Pb2＋ ions

We have prepared silica,SiO2coated NiO and NiO coated SiO2by sol-gel method.The physicochemical properties of the desired materials were investigated by surface charge properties,scanning electron microscopy（SEM）,energy dispersive X-ray（EDX） spectroscopy,surface area measurements and X-ray diffraction（XRD） analyses.The point of zero charge（PZC） of the solid was determined by the salt addition method.In coated materials,two PZC values were noted representing the surface charge of their counterparts.The SEM image of SiO2coated NiO displays a uniform coating of silica on the surface of NiO whereas in case of NiO coated SiO2,a honeycomb like appearance was observed with highly porous structures.In the diffractograms of NiO,the characteristic peaks were suppressed in NiO coated silica however,no diffraction peak could be seen in SiO2coated NiO.Batch adsorption technique was applied for the removal of Pb2＋ions from aqueous solution.The sorption trend for Pb2＋ions was observed in the order of NiO coated SiO2〉 SiO2coated NiO 〉 NiO 〉 SiO2.This trend confirms that the coated materials have more sorption capacities than their parent counterparts.     

Rapid synthesis of novel flowerlike K0.46Mn2O4(H2O)1.4 hierarchical architectures and their catalytic degradation of formaldehyde in aqueous solution

Novel flower-like birnessite type manganese oxide hierarchical architectures were hydrothermally synthesized from KMnO₄ solution using sodium fluorite as a reductant in sulfuric acid medium at low temperature. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and X-ray photoelectron (XPS) spectroscopes confirm that the composition of the as-fabricated product. Field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), selected area electron diffraction (SA-ED), high resolution transmission electron microscopy (HR-TEM) and N₂ adsorption–desorption isotherm reveal that the as-synthesized sample exhibits a microsized flower-like crystal with dense nanoleaves standing on their surfaces, polycrystalline, monoclinic phase structure and high BET surface area. On the basis of time-dependent experimental results, a possible mechanism for the formation of flowerlike structures is speculated. Their capability of catalytic degradation of formaldehyde solution with oxygen air bubbles were studied by using an acetylacetone calorimetric spectra, total organic carbon (TOC) method and turnover number (TON). In addition, the birnessite nanoflower is stable during the reaction and can be used repeatedly.     

物理混合法制备分级混晶TiO2微纳米材料及其光催化性能

通过物理混合法可控合成了分级混晶TiO₂微纳米材料, 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)、 X射线光电子能谱仪(XPS)和固体紫外-可见分光光度计(UV-Vis)等对该微纳米材料进行了表征, 并评价了不同混晶比材料的光催化性能. 结果表明, 所得材料是由均匀负载金红石纳米颗粒的锐钛矿纳米片组装的三维分级结构. 其具有很高的光催化活性, 分级结构和混晶异相结的同时引入是提高材料光催化活性的关键.     

Room temperature solution-phase synthesis of flower-like nanostructures of [Ni3(BTC)2·12H2O] and their conversion to porous NiO

Hierarchical flower-like architectures of[Ni₃（BTC）₂·12H₂O]（BTC³=benzene-1,3,5-tricarboxylate） were successfully prepared by a simple solution-phase method under mild conditions without any template or surfactant.Phase-pure porous NiO nanocrystals were obtained by annealing the Ni-BTC complex without significant alteration in morphology.The product was characterized by X-ray diffraction techniques,field-emission scanning electron microscopy（FESEM）.transmission electron microscopy（TEM） and high-resolution TEM（HRTEM）.The catalytic effect of the NiO product was investigated on the thermal decomposition of ammonium perchlorate（AP） and it was found that the annealed NiO product has higher catalytic activity than the commercial NiO.     

Controllable synthesis of NiC2O4·2H2O nanorods precursor and applications in the synthesis of nickel-based nanostructures

A controllable synthesis of NiC₂O₄·2H₂O nanorods precursor was obtained via the microemulsion-mediated solvothermal method and a further synthesis of β-Ni(OH)₂ nanorods, nickel oxide (NiO) sub-microtubes, Ni nanospheres and flower-like nickel complexes nanostructures by using the precursor. The morphologies and crystalline structures were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and the X-ray powder diffraction (XRD). The morphologies and sizes of the precursors can be readily tuned by adjusting experimental parameters of the reverse microemulsion system. The synthesized β-Ni(OH)₂ nanorods composed of fine nanosheets shown excellent electrochemical performance as an electrode material in rechargeable battery systems.     

LiFeO_2包覆MCFC氧化镍阴极的制备及性能研究

以硝酸锂和硝酸铁为原料 ,柠檬酸作燃料 ,采用燃烧合成法制备了铁酸锂包覆的多孔氧化镍阴极 .X_射线衍射技术 (XRD)、X_射线能量散射谱 (EDAX)和电子显微镜 (TEM和SEM )分析表明 ,在氧化镍颗粒表面的包覆层是由直径小于 10 0nm的铁酸锂微粒所构成 ,并与氧化镍颗粒紧密烧结在一起 ,有效地减少了氧化镍与熔融碳酸盐的接触面积 ,从而降低了氧化镍的溶解度 .同时 ,本文还研究了该阴极在熔融碳酸盐燃料电池中的电性能 ,并与未包覆的NiO阴极进行比较     

Fabrication of hollow spheres and thin films of nickel hydroxide and nickel oxide with hierarchical structures

Hollow spheres and thin films of Ni(OH)(2) and NiO with unusual form and hierarchical structures have been synthesized by a simple solution chemistry method. First, in situ formed Ni(OH)(2) nanoflakelets organized on the surface of styrene-acrylic acid copolymer (PSA) latex particles to form core/shell structures. Ni(OH)(2) hollow shells built up with nanoflakelets were obtained after subsequent removal of the core latex particles by dissolving PSA latex in toluene; the removal of the cores by calcinations would result in NiO hollow shells, also with hierarchical structures. BET calculation showed the surface area of the NiO hollow spheres was 156 m(2)/g. The nanoflakelets could also organize themselves into thin films with hierarchical structures. It is anticipated that these novel structures will have some unique applications in Ni-based batteries and other potentials.     

Flower-like porous hematite nanoarchitectures achieved by complexation-mediated oxidation-hydrolysis reaction

Flower-like porous hematite (α-Fe(2)O(3)) nanoarchitectures composed of ultra-thin nanoflakes were prepared by annealing the iron oxide precursor formed via the oxidation-hydrolysis reaction between Fe(II) ions and Tris(hydroxymethyl)aminomethane (abbreviated as Tris). The microstructure of the prepared FeOOH and hematite samples were fully characterized by field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, Fourier-transforming infrared spectra, thermogravimetric analysis, and nitrogen adsorption-desorption isotherm. Based on the influences of reactant concentrations, reaction time and reaction temperature on the morphologies of the resultant samples, a formation mechanism of etching was proposed, Fe(II)-Tris complexes were self-assembled via hydrogen bonds into brick-like building blocks, which then aggregated into rudimentary nanoparticles, and the synergistic effect between the crystallization of FeOOH and dissociation of Fe(II)-Tris complexes make the rudimentary nanoparticles evolve into the flower-like products. The as-prepared flower-like α-Fe(2)O(3) nanostructures possessed a Brunauer-Emmett-Teller specific surface area of 191.63 m(2)g(-1), hierarchical pore distribution ranging from micropores to macropores, and good crystallinity, and excellent visible photocatalysis in terms of removing chemical oxygen demand of dimethyl sulfoxide industrial wastewater. The current work provides a reliable approach for building functional hierarchical nanoarchitectures and the prepared iron oxide nanomaterials demonstrate an excellent ability to remove toxic pollutants in industrial wastewater.     

Chiral hierarchical molecular nanostructures on two-dimensional surface by controllable trinary self-assembly

The bottom-up fabrication of surface hierarchical nanostructures is of great importance for the development of molecular nanostructures for chiral molecular recognition and enantioselective catalysis. Herein, we report the construction of a series of 2D chiral hierarchical structures by trinary molecular self-assembly with copper phthalocyanine (CuPc), 2,3,7,8,12,13-hexahexyloxy-truxenone (TrO23), and 1,3,5-tris(10-carboxydecyloxy) benzene (TCDB). A series of flower-like chiral hierarchical molecular architectures with increased generations are formed, and the details of these structures are investigated by high resolution scanning tunneling microscopy (STM). The flower-like hierarchical molecular architectures could be described by a unified configuration in which the lobe of each architecture is composed of a different number of triangular shape building units (TBUs). The off-axis edge-to-edge packing of TBUs confers the organizational chirality of the hierarchical assemblies. On the other hand, the TBUs can tile the surface in a vertex-sharing configuration, resulting in the expansion of chiral unit cells, which thereby further modulate the periodicity of chiral voids in the multilevel hierarchical assemblies. The formation of desired hierarchical structures could be controlled through tuning the molar ratio of each component in liquid phase. The results are significant for the design and fabrication of multicomponent chiral hierarchical molecular nanostructures.     

放射孔二氧化硅及其核壳结构的制备与表征

室温下以十六烷基三甲基溴化铵(CTAB)为模板剂, 正硅酸乙酯(TEOS)为硅源, 氨水(质量分数25%)为催化剂, 在水-乙醇-乙醚作共溶剂的体系中以氨基化的实心二氧化硅(NH₂-sSiO₂)为添加剂, 制备了放射孔二氧化硅及其核壳结构(sSiO₂@rSiO₂). 通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、小角X射线衍射(XRD)、氮气吸附-脱附实验和孔径分布测定对其进行了表征和分析. 结果表明, 合成的产物为0.4~1 μm的球形粒子, 球上存在多级放射状孔道结构, 孔径从3 nm到几十纳米的多级孔径并存, 样品的Brunauer-Emmett-Teller(BET)比表面积为996 m²/g. 最后对放射孔二氧化硅的形成机理及核壳结构的影响因素进行了初步探讨.     

溶剂热法合成花朵状钴磁性粉体及表征

采用一种简单的溶剂热法成功的合成了花朵状的钴磁性粉体。通过X射线粉末衍射(XRD),扫描电子显微镜(SEM)等对样品进行物相与形貌的表征。结果表明样品为六排堆积(hcp)和面心立方结构(fcc)混合结构的钴单质,形貌为由很多个厚度约为50～150 nm的菱形花瓣构成的花朵状结构,每个花朵的尺寸约为2μm左右。采用振动样品磁强计(VSM)测试了样品的磁性能,测试表明样品在室温下表现出铁磁性,饱和磁化强度(Ms)为140 emu.g-1,剩磁(Mr)为9.4 emu.g-1,矫顽力(Hc)为280 Oe。     

Preparation of Superhydrophobic ZnO Films on Zinc Substrate by Chemical Solution Method

Superhydrophobic surface was prepared on the zinc substrate by chemical solution method via immersing clean pure zinc substrate into a water solution of zinc nitrate hexahydrate[Zn(NO₃)₂·6H₂O] and hexamethylenetetraamine( C₆H₁₂N₄) at 95 ℃ in water bath for 1.5 h, then modified with 18 alkanethiol. The best resulting surface shows superhydrophobic properties with a water contact angle of about 158° and a low water roll-off angle of around 3°. The prepared samples were characterized by powder X-ray diffraction(XRD), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy(EDX), transmission electron microscopy(TEM), and scanning electron microscopy(SEM). SEM images of the films show that the resulting surface exhibits flower-shaped micro- and nano-structure. The surfaces of the prepared films were composed of ZnO nanorods which were wurtzite structure. The special flower-like micro- and nano-structure along with the low surface energy leads to the surface superhydrophobicity.     

分级多孔结构ZnO微球的制备及其光电性能

采用简单的低温化学溶液沉积方法制备了分级多孔ZnO微球。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电镜(TEM)、N2吸附脱附以及紫外-可见分光光度计(UV-Vis)等对样品进行了表征。结果显示产物为分级多孔结构的ZnO微球,由直径约10~20 nm ZnO颗粒组装而成,比表面积为40 m2.g-1。把多孔ZnO微球用作染料敏化太阳能电池(DSCs)光阳极,结果表明,该光阳极在增强对入射光的散射作用的同时,为染料分子的吸附提供了较大比表面积,从而提高了DSCs的光伏性能。     

不同形貌ZnO纳米结构的电子显微分析

控制实验合成条件,利用溶胶-凝胶法和化学溶液生长法制备出不同形貌的ZnO纳米结构。采用X射线衍射仪(XRD)、扫描电子显微镜( SEM) 以及透射电子显微镜(TEM)等多种测试手段对ZnO纳米结构的微观形态及晶相进行了分析。结果表明:3种ZnO纳米结构形貌虽不同,但均具有Z nO六方纤锌矿晶相结构。ZnO纳米棒和花状ZnO纳米结构为单晶,生长方向均沿(0001)方向。ZnO纳米球则为多晶。     

In2O3/CdO复合材料的制备及气敏特性

采用水热合成方法制备了花状In2O3纳米材料.利用X射线衍射(XRD)、扫描电镜(SEM)、能量色散X射线光谱(EDX)及透射电镜(TEM)对材料的结晶学特性及微结构进行了表征.制备的In2O3材料呈现花状,是由粒径约20nm的椭球状小颗粒构成的分级结构材料.将制备的In2O3与纳米CdO以摩尔比1:1混合后,发现制成的In2O3/CdO复合材料经热处理后呈现葡萄状多孔结构.测试In2O3/CdO复合材料制作的气敏元件处于最佳工作温度(410°C)时,对0.05×10-6(体积分数,φ)的甲醛气体表现出较高的灵敏度.对比测试发现,In2O3/CdO复合材料制作的气敏元件对不同浓度甲醛的灵敏度明显优于纯花状In2O3纳米材料.同时In2O3/CdO复合材料制作的气敏元件在乙醇、甲苯、丙酮、甲醇以及氨气等干扰气体中具有对甲醛良好的选择性.讨论了In2O3/CdO复合材料气敏元件的敏感机理.     

TiO2@MWNTs纳米复合材料的制备及其储锂性能

以TiOSO4为钛源,多壁碳纳米管(MWNTs)为载体,溶剂热法制备了多壁碳纳米管/二氧化钛纳米复合材料(TiO2@MWNTs),并利用XRD,SEM,TEM,N2吸附-脱附和TG-DSC等测试手段对合成产物的结构和形貌进行表征,用恒流充放电测试研究TiO2@MWNTs纳米复合材料的储锂性能.N2吸附-脱附曲线和孔径分布曲线证实TiO2@MWNTs存在多级孔道结构以及较大的比表面积.电化学测试结果表明,与纯TiO2颗粒相比,TiO2@MWNTs纳米复合材料具有更好的容量保持率和倍率性能.在1 C倍率下,复合材料的可逆容量为200 mAh?g-1,循环100圈后容量仍达182 mAh?g-1,即使在10 C大倍率下,容量约为100 mAh?g-1左右.     

NiO亚微米球的制备及其光催化性质

在混合溶剂体系中,通过简单的二步方法成功合成了NiO亚微米球。第一步,以Ni(CH3COO)2和精氨酸为主要反应物,160℃溶剂热反应8 h制备出前驱体;第二步,煅烧前驱体成功合成了NiO产物。利用X射线粉末衍射(XRD),扫描电子显微镜(SEM),透射电子显微镜(TEM),热重分析(TGA)等手段对产物进行了表征。在紫外光照射下,研究不同光催化剂对甲基橙溶液降解效果。结果表明,NiO亚微米球在紫外光照射条件下对甲基橙溶液有光降解作用。     

多级结构Ni@CuS复合物的合成及在提高催化还原4-硝基苯酚性能方面的应用

三种多级结构花状硫化铜通过水热法,利用纳米薄片自组装形成.加入有机分子聚乙烯吡咯烷酮或1, 3, 5-均苯三甲酸调控其片层密度.产物作为基板生长镍纳米颗粒.通过环境扫描电子显微镜(SEM), X射线衍射(XRD),透射电子显微镜(TEM)等对这种复合物的结构进行表征.利用紫外-可见吸收光谱,研究了产物作为催化剂催化还原4-硝基苯酚的性能.结果表明,长在具有最稀疏片层的样品(Ni@SUB2)上的镍纳米颗粒(NiNPs,直径5 nm左右)具有超低负载量,为0.469% (w). Ni@SUB2在三种Ni@SUB复合物中具有最好的催化性能.还原4-硝基苯酚的反应中, 4-硝基酚初始浓度为0.2 mmol·L^-1时Ni@SUB2在4 min中内转化率可以实现100%,而等量的纯Ni纳米颗粒转化率只有43%.增强的催化性能可以归结为镍纳米颗粒在硫化铜基板上得到良好分散,可以提供更多催化位点.同时硫化铜基板不溶于水,可以通过离心的方式回收催化剂,有利于环境保护.