ZnO/AgBr复合纳米棒的制备及其光催化性能研究

以ZnNO3·6H2O、AgNO3、十六烷基三甲基溴化铵和氨水为原料,通过水热法制备了ZnO/AgBr复合纳米棒.利用SEM、XRD分别对产品的形貌和结构进行表征.以ZnO/AgBr复合纳米棒为光催化剂,通过降解有机污染物甲基橙进行了光催化活性测试,结果表明,在可见光照射150 min后,对甲基橙的降解率接近完全.     

TiO_2/ZnO双层电子传输层的制备及光电化学性能

首先在氟掺杂的氧化锡导电玻璃(FTO)上水热生长一层TiO_2纳米棒阵列薄膜,然后通过旋涂法旋涂ZnO籽晶层后水热法生长ZnO纳米棒得到TiO_2/ZnO纳米棒阵列薄膜。通过XRD、SEM、PL、UV-Vis和电化学工作站等对单层TiO_2纳米棒和TiO_2/ZnO纳米棒的结构、表面形貌、荧光性能、光吸收强度以及光电化学性质进行表征。结果表明,随着水热生长ZnO时间的增长,ZnO纳米棒密度增加; ZnO纳米棒的生长时间不同使其荧光强度不同,TiO_2/Zn O纳米棒的荧光强度与单层TiO_2纳米棒相比有着微小的减弱,没有明显的衍射峰; TiO_2/ZnO纳米棒复合材料比单层TiO_2的光吸收强度高,提高其光学性能,但是吸光区域都在紫外光区域;在标准模拟太阳光照射下,TiO_2/Zn O纳米棒的光电流为0. 002 m A,单层TiO_2纳米棒的光电流为0. 006 m A,复合薄膜的电流有着明显的变化。     

花状ZnO的水热合成与表征

以金属锌为原料,引入偶联表面活性剂作为晶体生长控制剂,在温和的水热条件(150℃)下一步合成了花状纳米结构的ZnO.使用XRD,TEM,SEM,SAED等测试手段,对产物的化学组成和形貌特征进行了分析和表征.结果表明,花状ZnO纳米结构由ZnO纳米棒组成,该ZnO纳米棒为六方晶系且表现为单晶性质.ZnO纳米棒纯度高、粒径较小、长直、光滑而且大多一端聚集而另一端向四周放射性分布,呈较完美的花状结构.初步探讨了ZnO单晶纳米棒和花状ZnO纳米结构的形成机理.分析表明,ZnO纳米棒及其花状结构的形成与偶联表面括性剂特殊的性质及分子结构有关.     

ZnO纳米棒的制备和气敏性质

以二水合醋酸锌为原料,以十二烷基苯磺酸钠为表面修饰剂,利用微乳液法合成了结晶良好的ZnO纳米棒.利用X射线衍射仪、扫描电子显微镜和高分辨透射电子显微镜对所得产物的晶体结构和形貌进行了表征.结果表明:所得的ZnO纳米棒具有六方纤锌矿结构,且尺寸分布均匀,直径为20～30 nm,长度为1.0 μm.利用所得ZnO纳米棒制备...     

ZnO纳米棒的制备及其光催化活性研究

以Zn(Ac)2·2H2O、NaI和N2H4·H2O为原料,在未使用任何表面活性剂的简单水热反应体系中制得了ZnO纳米棒.采用X射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)对产物的晶体结构、形貌进行了表征分析,并对其光催化活性进行了探讨,以ZnO纳米棒为光催化剂对有机染料污染物甲基橙进行了光催化降解实验.实验结果表明,氧化锌纳米棒对甲基橙的光催化降解具有很好的催化作用,在紫外光照射120min后,对甲基橙的降解率接近完全.     

ZnO/ZnS异质结构纳米棒的制备及性能研究

本文利用低温二步水热法在ITO玻璃衬底上制备了ZnO/ZnS异质结构纳米棒,研究和比较了Zn O纳米棒和ZnO/ZnS异质结构纳米棒的形貌,结构和光学等特性。结果表明:未掺杂的ZnO纳米棒具有明显的六角结构表面,良好的晶体结构和c轴生长取向;ZnO/ZnS异质结构纳米棒的形貌和光学性质都发生了变化,纳米棒直径变化范围大,六角结构表面六边形不规则,且引入了较多的深能级缺陷。     

氧化锌纳米棒的制备与表征

本论文探索一种良好制备ZnO纳米棒的方法。通过高分子络合软模板法在硅衬底和聚丙烯酰胺膜中间生长出顶面平滑具有六棱柱形结构的ZnO纳米棒。用扫描电子显微镜、X射线衍射仪对ZnO米棒微观形貌和结构进行分析:SEM观察到纳米氧化锌呈棒状,分布均匀且排列整齐;XRD图谱分析显示ZnO纳米棒为六方晶系的红锌矿型ZnO,且具有良好的晶体结构。     

La-Gd共掺ZnO纳米棒的性能及其应用研究

利用KH560交联剂来提高La-Gd/ZnO纳米棒阵列在棉织物上的牢度。以硝酸锌和六亚甲基四胺为原料,聚乙二醇2000为形貌控制剂,KH560为交联剂,采用低温水浴法制备在棉织物表面原位生长的La-Gd/ZnO纳米棒阵列。同时利用X射线衍射仪、扫描电子显微镜和紫外-可见光漫反射等方法对制备的样品进行表征和性能分析。结果表明:3%La-3%Gd/ZnO纳米棒具有良好的光催化性能,在紫外光下照射150 min,对亚甲基蓝溶液(MB)的降解率为92.15%;太阳光下照射8 h,对亚甲基蓝溶液(MB)的降解率为87.59%。且经过整理后的棉织物的抗紫外线指数UPF值由10.06提升至420.21。经水洗10次,其光催化性能仅下降1.3%,抗紫外线指数基本没有变化。     

不同醇溶剂中氧化锌纳米晶的可控制备

采用液相直接沉淀法,以醋酸锌和氢氧化钠为原料,在醇溶剂体系中成功制备出不同形貌的ZnO纳米晶,使用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和紫外-可见分光光度计(UV-vis)等检测方法对样品进行表征.结果表明,制备的ZnO均为六方纤锌矿结构,形貌受到溶剂种类、反应温度和反应时间等因素影响;在乙醇溶剂中,通过反应温度和反应时间控制可得到分散均匀、形貌均一纳米颗粒或纳米棒,并对不同形貌ZnO的生长机理进行了初步讨论.     

棒状纳米ZnO的制备及其光催化性能研究

采用溶胶-凝胶法,以醋酸锌、草酸为主要原料,乙二胺为添加剂制得棒状结构的纳米ZnO,通过XRD和TEM对产物的结构和形貌进行了表征,并以有机染料亚甲基蓝溶液为光催化反应模型降解物,考察了样品的光催化活性。结果表明,ZnO纳米棒为纤锌矿结构的六方相ZnO,对亚甲基蓝溶液具有良好的光催化活性,且乙二胺的添加量对产物的形貌和光催化活性具有显著影响。     

Preparation of ZnO nanorod by solvothermal reaction of zinc acetate in various alcohols

Solvothermal reaction of zinc acetate in various alcohols resulted in the formation of zinc oxide (ZnO) nanorods. The effects of reaction conditions on the product morphology as well as crystallization mechanism were investigated by using X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM) techniques. It was found that average diameter and length of the nanorods increased with an increase in reaction temperature or the initial concentration of zinc acetate. On the contrary, the aspect ratio of the product depended upon type of alcohol used as the reaction medium. The aspect ratio of ZnO nanorods increased from 1.7 to 5.6 when the alcohol was changed from 1-butanol to 1-decanol. An investigation of the reaction mechanism suggested that the formation of ZnO nanorods was initiated from the esterification reaction between zinc acetate precursor and alcohol to form ZnO seeds.     

Sonochemical synthesis of ZnO‐ZnS core‐shell nanorods for enhanced photoelectrochemical water oxidation

The ultrasonic‐assisted synthesis method provides a fast, simple, and large‐scale route for synthesizing desired materials under ambient conditions. In this work, we report on the facile preparation of ZnO‐ZnS core‐shell nanorods on a fluorine‐doped tin oxide (FTO) substrate. The core‐shell nanorods were synthesized by sequential nanoscale reactions involving the preparation of ZnO nanorods and conversion of the ZnO surface into a ZnS shell on the FTO substrate, using an in situ sonochemical method. The ZnO‐ZnS core‐shell nanorods showed improved photocurrents compared with ZnO nanorods for the water oxidation reaction. During the water oxidation reaction, the ZnS shell passivates the surface‐defects of the ZnO, which results in enhanced charge separation in the ZnO nanorods and higher performance.     

Influence of nanocrystalline diamond powder on the growth and photoluminescence of open-ended ZnO nanorods

This paper reports the influence of introducing nanocrystalline diamond powder on the growth and photoluminescence of ZnO nanorods fabricated by hydrothermal technique. The majority of ZnO nanorods show an open-ended feature due to the addition of nano-diamond powder in the reaction solution. It is speculated that the diamond nanocrystallines dropped on the top of the growing ZnO nanorods would suppress the further growth at the localized positions to form the open-ended nanorods. The photoluminescence spectra of the ZnO products show the band-edge-related UV emission of ZnO nanorods at ~ 380 nm, in addition to a broad visible band centered at about 650 nm, which may originate from the emissions related to defects in the open-ended ZnO nanorods. The open-ended ZnO nanorods and/or combined with diamond nanocrystallines would be favorable for potential applications including UV sensors, electron field emitter, and various photoelectric nanodevices.     

微波均相沉淀法制备纳米ZnO及其光催化性能

以硫酸锌和尿素为原料,采用微波均相沉淀法制备出了纳米ZnO. 探讨了反应物配比、反应物浓度、反应时间、反应温度等条件对产物的影响. 并用TEM, IR, TGA, XRD, UV-Vis等测试手段对其进行了表征. 利用紫外-可见分光光度计测试了光吸收特性,发现纳米ZnO对200~380 nm波长范围的光有很强的吸收性,在可见光范围内也有较强的吸收. 研究了纳米ZnO光催化降解甲基橙的动力学行为,在紫外光直接照射下,光催化降解甲基橙,以分光光度法测量甲基橙的即时浓度,从而得出了不同条件下甲基橙降解的脱色速率,以比较不同的降解效果.     

Role of OH− in the low temperature hydrothermal synthesis of ZnO nanorods

BACKGROUND: ZnO nanorods, which have a wide range of applications, were grown on a Si substrate by low temperature hydrothermal synthesis. An understanding of the reaction mechanism of ZnO nanorods is crucial to control their growth kinetics. Therefore, the effect of OH^? concentration in a zinc sulfate solution on the growth of ZnO nanorods was investigated in order to better understand the growth mechanism of ZnO nanorods. RESULTS: The growth rate and diameter of ZnO nanorods were increased by increasing the pH of the zinc sulfate solution from 10.4 to 10.6, and the highest growth rate, 850 nm h^?1, was observed when the nanorods were grown in a solution with a pH of 10.6. However, further increase in the pH of the solution decreased the growth rate, due to the simultaneous dissolution of ZnO nanorods by OH^?. The amount of OH^? consumed by the dissolution of ZnO and other subreactions was minimized in a solution with a pH of 10.6. The intensity of c‐axis (0001) orientation was the highest in the solution with a pH of 10.6. CONCLUSION: It is concluded that the concentration of OH^? plays a critical role in the hydrothermal synthesis of ZnO nanorods, and that the suppression of OH^? subreactions increases the growth rate of ZnO nanorods. From the changes in the length and diameter of ZnO nanorods with synthesis time, it is suggested that the nucleation of ZnO nanocrystals occurs in the first 30 min, from which the growth of nanorods then proceeds. Copyright © 2007 Society of Chemical Industry     

ZnO/碳纳米管复合光催化材料对抗生素的光催化降解

采用溶胶法合成了ZnO/碳纳米管复合光催化材料,采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射吸收光谱(UV-Vis)等手段对复合催化剂进行了表征。以氙灯(250～800 nm)为光源,盐酸四环素为降解对象,评价样品的光催化活性。比较ZnO/CNTs复合材料和纯ZnO对抗生素的降解能力,并考察光催化剂的重复利用能力。结果表明,通过溶胶法得到了在碳纳米管表面均匀、致密包覆ZnO颗粒的复合材料。由于ZnO/CNTs材料良好的吸附性能,其光催化活性高于纯ZnO,在300 W氙灯光源下反应2 h,对盐酸四环素的降解率达82.38%,同时复合材料显示了抑制ZnO光蚀的能力。     

溶剂热合成多级ZnO微球及其光催化降解苯酚

以乙二醇为溶剂,KAc为助剂,采用溶剂热法合成多级ZnO微球。通过改变反应温度来调控ZnO微球形貌,并对合成的ZnO微球进行XRD、SEM、PL和UV-Vis DRS等表征分析。结果表明,合成的ZnO为六方纤锌矿晶体结构,由短纳米棒自组装成多级微球。在紫外-可见光照射下,ZnO表现出优异的光催化降解苯酚活性,180℃合成的ZnO样品光催化活性明显优于其他温度合成的样品。用0.1 g的ZnO降解100 mL浓度为5 mg·L^(-1)的苯酚溶液,光照150 min降解率达94.5%。多级ZnO微球光催化性能的提高可推测为较窄的禁带宽度(3.08 eV)有利于吸收光子,较小的晶粒尺寸(25.38 nm)、粗糙的表面以及中空结构有利于反应液与催化剂表面的充分接触。此外,由捕获实验证实光催化降解苯酚的机理是羟基(·OH)为主要的活性自由基,在苯酚降解过程中起主要作用。     

Hydrothermal Growth of Vertical ZnO Nanorods

Vertically aligned, single crystalline ZnO nanorods with a high packing density and diameter of ∼60 nm have been successfully synthesized via a low-temperature hydrothermal route on glass substrates pre-deposited with a ZnO seeding layer. The seeding layer exhibits an epitaxial effect on the growth and alignment of the ZnO nanorods. This epitaxial effect can arise from two considerations, namely the crystalline orientation and surface roughness of the seeding layer, which can be controlled by the curing temperature. The ZnO seeding layer that was cured at 350°C exhibited a preferred (0002) crystalline orientation of wurtzite hexagonal structure and a low surface roughness. It was demonstrated to promote the vertical growth of ZnO nanorods. The ZnO nanorods grew in an almost linear relationship with hydrothermal time up to 8 h, but thereafter started to dissolve as the reaction time extended beyond 8 h, due to competition from the homogeneous nucleation of ZnO microparticles in the solution.     

La掺杂ZnO的制备及其光催化降解孔雀石绿

采用溶胶?凝胶法制备了不同La掺杂量的La/ZnO催化剂,分析了其组成和性质,以孔雀石绿溶液为染料模型,研究了催化剂的光催化降解性能. 结果表明,ZnO为六角纤锌矿结构,La3+以小La2O3簇的形式均匀分布在ZnO纳米颗粒上. 摩尔比La:Zn=0.05时La/ZnO具有良好的催化活性,用300 W汞灯照射2 h,孔雀石绿的降解率可达98.8%,300 W氙灯照射2 h降解率达90.4%,比ZnO的降解率提高了51.2%.     

纳米ZnO/膨润土光催化降解亚甲基蓝研究

以Zn(NO3)2和膨润土为原料,采用沉淀法制备纳米ZnO-膨润土复合光催化材料,用FT-IR、XRD和SEM对其结构和形貌进行了表征。以高压汞灯为光源,光催化降解活性亚甲基蓝模拟染料废水,研究了ZnO/有机膨润土光催化降解性能,讨论了影响亚甲基蓝降解率主要因素。结果表明,在光照射下1.5 h,ZnO/膨润土光催化降解亚甲基蓝达96%,其重复使用降解效果保持稳定,利用该复合光催化材料降解有机染料废水是一种可行的方法。