纳米氧化锌的制备及在水处理方面的应用

纳米氧化锌作为一种功能材料,有着许多优异的性能和广泛的应用。通过对纳米ZnO各种制备方法及其特点进行了对比,指出了各制备方法的特点、存在的问题,并介绍了纳米ZnO在光催化污水处理方面的应用及作用机理,最后对未来的应用研究提出了一些看法。     

木质素碳/氧化锌复合材料的制备及其光催化性能

以来源于造纸黑液的碱木质素和草酸锌为前驱体采用原位碳化法制备了不同碳含量的木质素碳/氧化锌(LC/ZnO)纳米复合材料。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、紫外分光光度计(UV-Vis)、荧光光谱仪(PL)等对所制备的LC/ZnO的微观结构和光学性质进行了表征。结果表明所制备的LC/ZnO复合材料是由高度分散的ZnO纳米颗粒和木质素碳纳米片构成,表现出优异的紫外和可见光吸收性能。以常见的有机污染物罗丹明B为降解对象,在模拟太阳光的照射下对所制备的LC/ZnO复合材料的光催化性能进行了研究。结果表明,LC/ZnO复合材料的光催化性能明显优于纯的ZnO纳米颗粒和氧化石墨烯/ZnO复合材料,且在550℃炭化温度下所制备的LC/ZnO-550复合材料具有最佳的光催化性能。     

掺杂对纳米氧化锌光催化性能的影响

以纳米氧化锌为载体,采用离子掺杂的方法制得了银掺杂纳米氧化锌(Ag/ZnO)及稀土铈掺杂纳米氧化锌(Ce/ZnO)光催化剂。实验结果表明:制备的Ag/ZnO粒径在18nm左右,Ce/ZnO粒径在20nm左右,离子掺杂有效提高了纳米氧化锌的光催化性能,并且Ag/ZnO试样的效果要好于Ce/ZnO试样。     

回归模型下的纳米ZnO材料制备及性能分析

纳米材料是将处于纳米级别的颗粒物作为基本单元而制备的材料,在纳米技术不断更新过程中,纳米材料被应用在航空和国防以及生物制药等诸多领域。为提高纳米ZnO材料的性能,研究回归模型下的纳米ZnO材料制备及性能,通过回归模型来确定最佳的纳米ZnO材料制备工艺条件,以达提高性能的目的。选定测试原料与设备,设定纳米ZnO材料制备工艺,确定纳米ZnO材料性能测试。之后建立回归模型确定纳米ZnO材料最佳制备工艺条件,并对该模型进行检验,最后将所制备纳米ZnO材料与市售纳米ZnO材料进行紫外-可见漫反射光谱（DRS）、XRD图谱以及光催化降解性能比较。实验结果表明,所制备纳米ZnO材料结晶度达到75.8%,吸收波长为620nm,有较好的吸收,且50min后降解率达98.95%,活性较高。     

两种形貌纳米ZnO的制备及其光催化性能测试

在超声辅助下,以醋酸锌、柠檬酸、乙醇和氢氧化钠为原料利用水热合成法成功一步合成纳米氧化锌,通过控制乙醇和柠檬酸的用量来控制纳米ZnO的形貌,得到了球形和花状两种纳米ZnO材料。表征发现:材料具有很好的形貌,XRD图谱分析认为,材料均具有极好的结晶度;并同时从机理方面探讨了不同形貌形成的原因;最后,利用酸性品红在高压汞灯的照射下测试了不同材料的光催化性能。结果表明:该法制备的材料性能稳定,质地均匀,拥有良好的光催化能力。球状的纳米ZnO材料略优于花状纳米ZnO材料的光催化性能,对20mg/L酸性品红溶液的降解率可达93.9%。     

纳米氧化锌的制备及光催化性能研究进展

纳米氧化锌作为一种具有优良光催化性能的半导体材料,其制备方法及光催化性能研究受到广泛关注。对近几年来纳米氧化锌的合成工艺、光催化降解有机污染物方面的应用研究做一综述,并展望其未来发展。     

聚丙烯酸酯-ZnO杂化材料的光催化性能研究

为了提高纳米ZnO的光催化性能,采用溶液共混法制备了聚丙烯酸酯- ZnO杂化材料,对其光催化性能进行了研究,采用FT - IR、TG -DTG对杂化材料进行了测试.结果表明:杂化材料的光催化性能优于纳米ZnO,降解率可达92.31％,随着ZnO含量增加,杂化材料的光催化性能先增加而后下降.杂化材料具有良好的重复使用性能.FI - IR分析表明在杂化材料中聚丙烯酸酯通过羧酸盐键与纳米ZnO发生杂化.UV - Vis分析表明甲基橙降解较完全.TG - DTG分析表明,杂化材料具有优良的热稳定性,杂化材料的热分解温度可达408℃.     

ZnO/石墨烯复合材料的制备及性能研究

本文将采用溶胶-凝胶法制备纳米ZnO和通过Hummers法制备的石墨烯进行简单的一步超声复合,得到ZnO/石墨烯复合材料。利用XRD、TEM以及紫外可见分光光度计对所制备的ZnO和石墨烯样品进行测试表征,并以亚甲基蓝的降解效率来评价ZnO/石墨烯复合材料的光催化活性能。研究表明:ZnO/石墨烯的光催活性较纯氧化锌提高了4倍有余,当石墨烯质量比为15%时,ZnO/石墨烯的光催化活性最强。     

纳米氧化锌光催化剂的制备及应用

综述了纳米金属氧化锌材料半导体光催化剂的化学结构和应用性能的一些相关技术研究进展,包括影响纳米氧化锌半导体材料光催化化学结构和应用性能的一系列重要因素,如氧化锌的形貌、尺寸大小、离子掺杂、半导体复合等以及纳米氧化锌与纳米氧化锌和氧化锌复合材料的制备与应用。氧化锌作为一种宽禁频射带的新型半导体材料,具有良好的电学、光学和电子催化性能,是一种具有广阔发展空间的新型光催化材料。     

静电纺丝法制备Y掺杂ZnO纳米材料及其光催化性能

通过调节前驱液组分,使用电纺丝法和焙烧工艺,制备Y掺杂ZnO纳米颗粒,采用透射电子显微镜、X射线衍射、光致发光光谱、N_2吸附-脱附和XPS等进行表征。结果表明,Y掺杂ZnO材料具有明显的球形结构,与纯ZnO相比,纳米粒径更小,结构更疏松,具有较大的比表面积,晶体材料的禁带宽度相应变窄。光催化污染物降解实验表明,Y掺杂ZnO能够提高ZnO材料的光催化性能,Y掺杂物质的量分数为0.25%时,光催化降解性能最好,表明Y掺杂是一种有效提高ZnO材料光催化性能的改性手段。     

掺杂ZnO光催化剂研究进展

ZnO作为半导体光催化剂,具有无毒性、高效性和低成本等优点得到广泛研究。但是ZnO禁带宽度较宽,为3.37 eV,仅能吸收紫外光,而且光生电子和空穴较容易复合,在太阳光照射下,表现出较低的光催化活性,不能满足工业应用要求。对ZnO进行改性能够提高ZnO对可见光的利用率及光催化活性。其中,对ZnO进行掺杂能够有效改变光催化剂的比表面积、颗粒大小和光催化活性等性质,适当引入一些金属或非金属离子有可能使催化剂对光的吸收范围扩展到可见光区。金属掺杂能使ZnO形成更多的晶格缺陷,降低电子和空穴的复合几率;而非金属掺杂能够在ZnO晶格中引入氧空位以及引起ZnO晶格膨胀,使ZnO禁带变窄,进而能吸收可见光;同时,掺杂两种非金属有可能比掺杂单一非金属更能改善ZnO对可见光的吸收。结合金属掺杂与非金属掺杂的优点,金属与非金属共同掺杂到ZnO中,使ZnO的各种缺点得到全面改善。此外,利用金属氧化物对ZnO进行掺杂,可改变ZnO晶格结构以及表面电子状态,提高ZnO光催化活性。需加强对掺杂理论的研究,掺杂虽能使ZnO能够吸收可见光,但是对可见光吸收不强,对太阳能利用率不高,需要对ZnO改性方法进行更深入研究,同时,光催化要进一步在工业上进行应用,应加强对光催化降解多组分废水及真实废水进行研究,其稳定性、固载化及其回收利用方面也应该得到更多关注。     

Highly visible light active Ag@ZnO nanocomposites synthesized by gel-combustion route

Highly visible light active 1% and 3% Ag@ZnO nanocomposites were synthesized via a gel combustion route using citric acid as a fuel. The formation of the nanocomposites with enhanced properties was confirmed using a range of characterization techniques, photocatalysis and photoelectrochemical studies. Compared to the pristine ZnO nanoparticles, the Ag@ZnO nanocomposites exhibited enhanced visible light photocatalytic activity for the degradation of methylene blue and photoelectrochemical response. A mechanism was proposed to account for the photocatalytic activities of the Ag@ZnO nanocomposite that showed the surface plasmon resonance (SPR) of Ag is an effective way of enhancing the visible light photocatalytic activities.     

硬脂酸修饰纳米氧化锌的制备及可见光光催化性能研究

以硫酸锌和氢氧化钠为原料,硬脂酸为修饰剂,采用一步沉淀法制备出硬脂酸修饰的纳米ZnO,并对可见光光催化性能进行了研究。借助XRD、TEM、FTIR、UV-vis等测试手段对硬脂酸修饰的纳米ZnO进行表征。结果表明,硬脂酸修饰的纳米ZnO分散比较均匀,硬脂酸与纳米氧化锌之间形成了化学键,而且硬脂酸修饰后,纳米ZnO更易被可见光激发,当甲基橙初始浓度为5 mg/L,硬脂酸修饰的纳米ZnO投加量为10 mg/L,光照时间70 min,硬脂酸修饰的纳米ZnO对甲基橙的降解率达到82.3%。     

Structural,optical and photocatalytic properties of hafnium doped zinc oxide nanophotocatalyst

A series of novel hafnium (Hf) doped ZnO nanophotocatalyst were synthesized using a simple sol–gel method with a doping content of up to 6 mol%. The structure, morphology and optical characteristics of the photocatalysts were characterized by XRD, SEM, TEM, FTIR, XPS, DRS and PL spectroscopy. The successful synthesis and chemical composition of pure and doped ZnO photocatalysts were confirmed by XRD and XPS. DRS confirmed that the spectral responses of the photocatalysts were shifted towards the visible light region and showed a reduction in band gap energy from 3.26 to 3.17 eV. Fluorescence emission spectra indicated that doped ZnO samples possess better charge separation capability than pure ZnO. The photocatalytic activity of Hf-doped ZnO was evaluated by the methylene blue (MB) degradation in aqueous solution under sunlight irradiation. Parameters such as irradiation time and doping content were found effective on the photoactivity of pure ZnO and Hf-doped ZnO. The photocatalysis experiments demonstrated that 2 mol% Hf-ZnO exhibited higher photocatalytic activity as compared to ZnO, ZnO commercial and other hafnium doped ZnO photocatalysts and also revealed that MB was effectively degraded by more than 85% within 120 min. The enhanced photoactivity might be attributed to effective charge separation and enhanced visible light absorption. It was concluded that the presence of hafnium within ZnO lattice could enhance the photocatalytic oxidation over pure ZnO.     

Supported Electrospun Ultrafine Fibrous Poly(tetrafluoroethylene)/ZnO Porous Membranes and their Photocatalytic Applications

Supported photocatalytic poly(tetrafluoroethylene) (PTFE)/ZnO porous membranes were prepared by sintering electrospun PTFE/poly(vinylalcohol)/zinc acetate dehydrate composite membranes. Electrospun PTFE membranes were utilized as supports with excellent chemical stability and high specific surface area, while the photocatalyst‐ZnO particles derived from the thermal decomposition of zinc acetate dehydrate were homogeneously immobilized on the surface of ultrafine PTFE fibers. The PTFE/ZnO membranes could be easily recovered and reused after water treatment. PTFE/ZnO membranes are expected to have a wide range of potential applications in photocatalysis and photocatalysis‐membrane reactors, playing the role of a catalyst as well as a selective barrier against contaminants of interest.     

CaF_2/ZnO的制备及光催化性能研究

ZnO因其费用低、活性高、无毒等特点,在光催化领域有着广泛的应用前景。通过向ZnO中掺入其它物质制备复合材料,可以达到调控ZnO的光催化性能的目的,扩大ZnO的具体应用范畴。以ZnO为主体研究材料,向ZnO中加入不同质量比的CaF_2,通过沉淀法制备CaF_2/ZnO复合材料。利用x-射线衍射分析(XRD)、扫描电镜(SEM)等手段对此复合材料的晶相、组份及微观结构进行表征。通过紫外-可见吸收光谱研究该复合材料在可见光、紫外光下降解亚甲基蓝的效率,发现与纯ZnO相比,可见光下CaF_2/ZnO复合材料对亚甲基蓝的降解效率随着掺入CaF_2的质量比的提高,呈现先下降后升高的趋势;而紫外光下CaF_2/ZnO复合材料对亚甲基蓝的降解效率都要比纯ZnO要高。     

阴极共电沉积制备ZnO/α-FeOOH复合膜及其光催化活性(英文)

利用阴极共电沉积法,在铟锡氧化物涂层玻璃基体上成功制备了ZnO/α-FeOOH复合膜。用X射线衍射和X射线能量散射谱分别对其晶相和化学组成进行了表征,以Cr(VI)的光催化还原作为探针反应评价了其光催化活性。结果表明:与单一的ZnO膜相比,不论是在紫外光还是紫外-可见光照射下,ZnO/α-FeOOH复合膜均呈现出更高的光催化活性。紫外光照射下,ZnO/α-FeOOH复合膜催化活性的提高主要应归因于异质结界面上光生电荷的有效分离,而掺杂到ZnO中的Fe(III)的电子捕获效应在紫外-可见光条件下也发挥着重要作用。     

Attachment of ZnO nanoparticles onto layered double hydroxides microspheres for high performance photocatalysis

In this study, ZnO nanoparticles were successfully deposited on the surface of ZnMgAl–CO₃–LDHs microspheres to form ZnO/ZnMgAl–CO₃–LDHs heterojunction photocatalysts by coprecipitation process. The samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV–vis diffuse reflectance spectroscopy. The results show that ZnO nanoparticles with diameters about 10–80 nm are tightly grown on the nanosheets of the ZnMgAl–CO₃–LDHs microspheres. Compared with the pristine ZnMgAl–CO₃–LDHs microspheres and pure ZnO, the photocatalytic activity of the heterojunction ZnO/ZnMgAl–CO₃–LDHs photocatalyst is significantly enhanced towards the degradation of phenol under UV light irradiation. The enhancement of the photocatalytic activity of the heterojunction catalysts can be ascribed to their improved light absorption property and the lower recombination rate of the photoexcited electrons and holes during the photocatalytic reaction. The optimal molar ratio of ZnO/ZnMgAl–CO₃–LDHs for the photocatalysis is 3. The heterojunction photocatalyst ZnO/ZnMgAl–CO₃–LDHs may be a promising photocatalyst for future application in water treatment due to its excellent performance in degradation of phenol.     

An eco-friendly highly stable and efficient Ni-C-S codoped wurtzite ZnO nanoplate: a smart photocatalyst for the quick removal of food dye under solar light irradiation

In recent years, semiconductor photocatalysis has become more and more attractive and important since it has great potential to contribute to such environmental problems. This work investigates the photodegradation of tatrazine using Ni, C and S codoped ZnO (Ni-C-S/ZnO) nanoplates synthesized by the co-precipitation method. The synthesized photocatalyst was characterized by UV–visible-diffuse reflectance spectroscopy (UV–vis-DRS), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. Ni-C-S/ZnO were found to be more photoactive than ZnO, Ni-ZnO and C-S/ZnO for the degradation of tatrazine under solar light irradiation. Ni, C and S, with a moderate amount (0.5:0.5:0.5:1) doped on ZnO, can act as electron traps and suppress the photogenerated electron–hole pair recombination and result in the improvement of photocatalytic performance samples. The optimum condition for 94% degradation was found to be 300 mL of 10 µM of dye solution along with 0.1 g/L of Ni-C-S/ZnO under solar light irradiation within 90 min. From this, the Ni-C-S/ZnO sample exhibited maximum photocatalytic efficiency for the degradation of tatrazine under solar light irradiation.     

Zr–Al共掺对ZnO光催化剂结构和催化性能的影响

利用水热处理结合焙烧的方法分别制备了Zr、Al掺杂及Zr–Al共掺的ZnO光催化剂。研究了制备的光催化剂样品的相结构和光谱性能;以紫外光(λ=254nm)为光源,酸性橙Ⅱ为降解对象,进行光催化活性测试;考察了Zr、Al掺杂对ZnO光催化剂反应活性的影响。研究表明,制备的产物均为六方晶系纤锌矿结构的ZnO;Zr、Al掺杂及Zr–Al共掺的ZnO样品的光催化活性相对于纯ZnO均有较大程度的提高,而且Zr–Al共掺的ZnO的光催化性能明显优于单一掺杂的。Zr–Al共掺可以明显改善ZnO表面状态,使ZnO具有更丰富的表面羟基,同时可以抑制光生电子–空穴对的复合,从而有利于光催化活性和稳定性的提高。