中空氧化锌微球的制备及应用研究进展

中空ZnO微球具有密度低、比表面积大、渗透性好、光电性能优异等特点,受到科研工作者的广泛关注。综述了中空ZnO微球的制备方法及其应用领域,首先,主要阐述了硬模板法、软模板法、自模板法和无模板法4大类制备方法的研究进展,其次,介绍了中空ZnO微球在光催化、太阳能电池、气体传感器及生物医药等领域的应用进展,最后,对中空ZnO结构材料的发展前景进行了展望。     

硬模法制备无机空心球的研究进展

结构与组成可控、性能可调的微米-亚微米尺度的无机空心球具有极大的应用潜力.系统评述了胶粒模法和胶囊模法等无机空心球的硬模制备方法,阐述了硬模法在均相母液和非均相母液中的不同成壳机制,综述了硬模法制备无机空心球的相关应用及最新进展.     

氧化锌空心球的制备及光致发光特征

采用水热和硬模板辅助技术,成功制备得到ZnO空心球结构.以葡萄糖和锌盐为原料,首先通过催化葡萄糖聚合-原位离子吸附一步进行(一步法)或葡萄糖聚合成球-离子吸附分步进行(二步法)制备锌/炭复合微球,然后经空气低温氧化制得ZnO空心球.用XRD、SEM、TEM研究产物的组成和结构及形貌,用光致发光光谱(PL)测试产物的室温光致发光性能.研究发现,两种方法得到的空心球壳均属多孔结构,由ZnO纳米粒子构成;与聚合-吸附分步法相比,聚合-原位离子吸附一步法更加简单快捷;制得的ZnO空心球结构材料具有良好的近紫外发光性能.对ZnO空心球结构的形成过程和可能的机制进行了分析和讨论.     

不同形貌ZnO的制备及其光催化性能研究

以柠檬酸钠为辅助剂,通过改变其加入量采用水热法制备不同形貌的ZnO。分别运用X射线衍射、扫描电子显微镜、透射电子显微镜和比表面积等手段对样品进行分析,并对生长机理进行了研究。另外,采用氙灯模拟太阳光,来探讨不同形貌ZnO对有机染料亚甲基蓝溶液的降解效果。结果表明:水热法合成的最终产物均为结晶性良好的六方纤锌矿,随着柠檬酸钠量的增加,ZnO的形貌由棒状花型到中空微球再转变为核壳结构微球。当柠檬酸钠用量为0.02g时,得到2~4μm的中空微球ZnO具有较高的催化活性,主要归功于其具有较大的比表面积(22.53m2/g)和特殊的内部空穴结构。     

纳米氧化锌中空柱的制备及其光催化性能的研究

以醋酸锌和氨水为原料,超声法制备出氧化锌中空柱,采用扫描电镜(SEM)、X射线衍射(XRD)、Uv-vis漫反射对纳米ZnO的形貌、结构进行了表征,以有机染料亚甲基蓝溶液为光催化反应模型降解物,考察纳米ZnO的光催化性能。结果表明:制备出的纳米氧化锌呈中空的柱形,长约2～3μm,直径约300nm,壁厚约40nm,结晶良好。当加入纳米ZnO为0.4g/L,光降解时间为75min,对亚甲基蓝溶液的降解率可达到99.08%。     

中空ZnO微球的制备及其光催化性能

以葡萄糖和醋酸锌为原料,采用模板法制备中空ZnO微球。并对所制样品进行表征,讨论了碳微球与醋酸锌物料比、煅烧温度、煅烧时间对ZnO催化剂光催化活性的影响。结果表明:在碳微球与醋酸锌物料比为1∶2、煅烧温度500℃、煅烧时间2h条件下,所制备的中空ZnO微球直径约为3~5μm,六方晶系结构,具有较好的光催化活性。     

二氧化锡纳米中空球制备研究进展

综述了近年来纳米二氧化锡中空球的制备方法,包括硬模板法、软模板法、溶胶-凝胶法、水热法、奥斯特瓦尔德熟化法、一步烧结法、超声喷雾热解法等。对纳米二氧化锡中空球材料的发展前景和制备方法进行了展望。     

TiO2-ZnO复合中空微球的制备及光催化性能

以Ti（SO₄）₂和Zn（NO₃）₂为原料,采用水热法制备TiO₂-ZnO复合中空微球光催化剂。通过FTIR、XRD、SEM、紫外可见漫反射光谱（UV-Vis DRS）、XPS及N₂吸附-脱附等方法对TiO₂-ZnO复合光催化剂的结构和性能进行表征,并以亚甲基蓝（MB）为目标降解物,评价TiO₂-ZnO复合中空微球光催化活性。结果表明,TiO₂-ZnO光催化剂具有中空微球结构,粒径为1~2 μm,比表面积为30.46 m2/g。TiO₂的加入可提高ZnO对光的吸收,有效降低电子空穴复合率。在高压Hg灯照射下,TiO₂-ZnO复合中空微球的光催化性能均高于纯ZnO,其中Zn（NO₃）₂与Ti（SO₄）₂摩尔比为1:0.7条件下制备的TiO₂-ZnO复合中空微球样品表现出较好的光催化活性,光照60 min,对MB的降解率可达95.8%,其光催化降解速率是纯ZnO的4.3倍。      

液相法制备氧化锌纳米粉体的研究进展

液相法是制备性能良好的氧化锌粉体的有效方法,因其制备形式的多样性、工艺简单、产物组成易控等特点而得到广泛应用.概述了液相法合成纳米ZnO粉体的研究进展,重点介绍了几种基本的液相合成法,如沉淀法、溶胶-凝胶法、水热法、微乳液法、超重力法,比较其优缺点,并对进一步的研究方向和发展趋势提出了见解.     

聚合物中空微球材料研究进展

聚合物中空微球材料因其具有特殊的空心结构和独特的性能,被广泛应用于诸多领域,并具有广阔的应用前景,已成为近年来的研究热点。文中主要介绍了近年来聚合物中空微球材料的制备方法,包括模板法,层层组装法,微封装法,乳液聚合/冷冻干燥法,胶束自组装法,溶胀法等,并对各种方法的优缺点以及近期的研究进展进行了总结,阐述了聚合物中空微球材料在生物医药、涂料及自修复材料领域的应用,最后对聚合物中空微球材料的发展进行了总结和展望。     

Hollow flower-like ZnO: Synthesis,growth mechanism and application in polyacrylate

Hollow flower-like ZnO (HF-ZnO) was fabricated via an ultrasonic-assisted hydrothermal method. The effect of pretreatment way and hydrothermal time on the morphology of ZnO was investigated to elucidate the growth mechanism of HF-ZnO. Subsequently, HF-ZnO was introduced into polyacrylate to form the composite film, and the properties especially water vapor permeability and water resistance of which were measured. The results showed that HF-ZnO was assembled by 1D-cones as petals, on which had massive cavities. The method and sequence of pretreatment both played a vital role in the growth of HF-ZnO. The generation of HF-ZnO must be carried out under the simultaneous existence of mechanical stirring and ultrasonic bathing. The flower-like structure of HF-ZnO was created in the step of pretreatment and hollow structure of HF-ZnO was produced in the step of hydrothermal. Compared with flower-like ZnO and hollow ZnO spheres, HF-ZnO was largely beneficial to the improvement of hygienic property of polyacrylate film. Moreover, the introduction of HF-ZnO enhanced the water resistance, tensile strength, UV resistance and anti-yellowing of polyacrylate film.     

水热碳化法制备碳纳米材料

形态可控的碳纳米材料由于独特的结构和性能而受到研究者的普遍关注,常见的制备方法有化学气相沉积法(CVD)、乳液法和水热碳化法等。水热碳化法是一种重要的碳纳米材料制备方法,具有成本低、反应条件温和、产物粒径均匀且形态可控等特点。综述了近年来以糖类及淀粉等有机物为原料,采用水热碳化法制备各种形态可控碳纳米材料的研究现状,重点介绍了水热碳化工艺条件对合成碳微球、空心碳微球、核壳结构碳复合材料显微形貌的影响,并提出了水热碳化法制备碳纳米材料研究中存在的问题和今后可能的发展方向。     

Rapid microwave-assisted synthesis of hierarchical ZnO hollow spheres and their application in Cr(VI) removal

A rapid one-pot synthesis of hierarchical ZnO hollow spheres consisting of nanoparticles was realized by a facile microwave-assisted solvothermal method using ethanol as the solvent. According to the time-dependent observation of the formation process, a tentative mechanism based on ethyl acetate bubble-templating self-assembly of ZnO nanoparticles was proposed for the formation of the ZnO hollow spheres. Compared with the conventional heating, the microwave irradiation resulted in a significantly shortened reaction time (within 30?min) and considerably improved quality of the ZnO hollow spheres, such as narrower size distribution and more regular morphology, owing to the high heating rate and thus the accelerated reaction rate. It was shown that the microwave-assisted synthesis of ZnO nanostructures with tunable morphologies can be realized by judicious selection of appropriate solvents. The obtained ZnO hollow spheres exhibited an excellent adsorption capacity towards Cr(VI) ions in water because of their high surface area for adsorption and a good ability to preserve the accessible surface.     

A simple one-step solvothermal synthesis of hierarchically structured ZnO hollow spheres for enhanced selective ethanol sensing properties

A simple one-step solvothermal method, using ethanolamine as solvent without any additives except zinc source, has been employed to synthesize hierarchically structured ZnO hollow spheres consisting of numerous orderly and radical nanorods with diameter of several tens nanometers and length of 2–3 μm. The ethanolamine and the solvothermal process play the critical role in the synthesis of the ZnO hollow spheres by the primary formation of ZnO crystal nucleus and subsequent transformation into nanorods, which self-assemble into hollow spheres. The morphology and structure of the spheres have been characterized by transmission electron microscopy, field emission scanning electron microscopy, X-ray powder diffraction, high-resolution transmission electron microscopy, and Brunauer–Emmett–Teller N₂ adsorption–desorption analyses. The results also indicate that the sensor based on the prepared ZnO hollow spheres exhibit good ethanol sensing performance, which can be attributed to its structural defects and high surface-to-volume ratio that significantly facilitate the absorption of oxygen species and diffusion of target gas. Besides, the sensor shows high selectivity to ethanol because ZnO as a basic oxide is favored for dehydrogenation of ethanol.     

水热法一步合成纳米/微米级ZnO球

采用水热法在较低的温度(160℃)下一步合成了高纯的六方相ZnO纳米/微米球,它们是由纳米颗粒聚合而成的.讨论其生长机制发现,在这个合成体系中,H2O起到了非常关键的作用.X射线衍射(XRD)谱中各衍射峰清晰且尖锐,说明ZnO结晶性能良好.扫描电子显微镜(SEM)、场发射扫描电子显微镜(FESEM)和透射电子显微镜(TEM)照片表明,在其他条件固定的情况下,可以通过调节三乙醇胺和水的体积比有效地控制ZnO球的尺寸和形状.紫外可见吸收光谱的吸收峰随着ZnO球直径的增加出现红移现象.     

水热法合成α-氧化铝空心微球

以葡萄糖和硝酸铝为原料,采用水热法合成大小及壁厚可控的α-氧化铝空心微球。通过扫描电子显微镜(SEM)、傅立叶红外光谱分析仪(FT-IR)、X射线衍射(XRD)、热分析(TG-DSC)等手段对合成产品进行表征。结果表明:得到的氧化铝空心微球分散性较好,可通过调节加入的葡萄糖浓度及硝酸铝量,得到大小及壁厚不同的氧化铝空心球,烧结温度对微球粒径大小影响不大,当烧结温度上升900℃时,壳层结构由不定形态变为γ-Al2O3,当烧结温度上升到1 100℃时,可得到α-Al2O3氧化铝空心微球。     

A novel synthesis of micrometer silica hollow sphere

Silica microcapsules (hollow spheres) were synthesized successfully by a novel CTAB-stabilized water/oil emulsion system mediated hydrothermal method. The addition of urea to a solution of aqueous phase was an essential step of the simple synthetic procedure of silica hollow spheres, which leads to the formation of silica hollow spheres with smooth shell during hydrothermal process. The intact hollow spheres were obtained by washing the as-synthesized solid products with distilled water to remove the organic components. A large amount of silanol groups were retained in the hollow spheres by this facile route without calcination. The morphologies and optical properties of the product were characterized by transmission electron microscopy, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy. Furthermore, on the basis of a series of SEM observations, phenomenological elucidation of a mechanism for the growth of the silica hollow spheres has been presented.     

Preparation and photocatalytic activity of hollow ZnO and ZnO-CuO composite spheres

ZnO and ZnO-CuO composite hollow spheres were fabricated by using colloidal carbon spheres as templates. The morphology, structure and chemical composition of the as-prepared samples were investigated using field emission scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The photocatalytic activity of the hollow spherical products was evaluated by photocatalytic degradation of methylene blue (MB) aqueous solution at ambient temperature. The results indicated that the ZnO-CuO composite hollow spheres display higher photocatalytic efficiency than pure hollow ZnO products. The related photocatalytic mechanism was discussed based on the microstructure and properties of the ZnO and ZnO-CuO composite hollow spheres. The facile strategy for the preparation of ZnO-CuO hollow nanostructures can be applicable to the synthesis of other composite hollow spheres.     

Bi_2MoO_6空心球的水热沉淀法制备及其光催化性能

以葡萄糖为前躯体,采用水热法制备胶体碳球,以其为模板通过水热沉淀法制备C/Bi2MoO6核壳结构,然后在350℃空气中煅烧,获得了具有良好光催化性能的Bi2MoO6空心球.通过SEM、XRD、FT-IR和BET等测试方法对该催化剂进行了表征;并对其形成机理及反应过程进行了初步探讨,以亚甲基蓝作为被降解物质,研究了其光催化活性。结果表明,Bi2MoO6空心球是由纳米晶粒组成的,壁厚约为30～50nm,平均直径约为0.6～0.8μm,采用胶体碳球作模板时制得的Bi2MoO6空心球比表面积为11.315m2/g,而直接合成的粉体比表面积为3.378m2/g。在黑管灯照射下,2.5h亚甲基蓝的降解率达到了91.95%。