CTAB辅助合成纳米复合材料Ag/ZnO-TiO2及其紫外光催化性能

在模板剂溴化十六烷基三甲基胺(CTAB)的辅助作用下,按nAg∶nZn∶nTi=0.1∶2∶1的物质的量的比,采用溶胶-凝胶再结合程序升温溶剂热法制备了一系列纳米复合材料Ag/ZnO-TiO2(CTAB),并经X射线衍射(XRD)、紫外-可见漫反射吸收光谱(UV-Vis/DRS)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)、扫描电子显微镜配合X射线能量色散谱仪(SEM-EDS)和N2吸附-脱附测定等测试手段对不同温度(500、600、700℃)和不同时间(5、7 h)下煅烧得到各产物的组成、结构及形貌等进行了表征。结果表明,该系列复合材料不仅含有ZnO纤锌矿和TiO2锐钛矿结构,同时有部分Zn2TiO4生成,其Ag还以单质形式存在。在CTAB作用下改变煅烧温度和时间可使各产物分别呈现纳米线、纳米球等多种形态,且颗粒分布较均匀。上述各复合材料在紫外光作用下对罗丹明B(RB)的光催化降解结果显示,样品煅烧温度和煅烧时间不同,其活性会发生明显的变化。     

圆形片状纳米复合材料Ag/ZnO-ZrO2微波辅助合成与多模式光催化罗丹明B

采用微波辅助结合沉淀法制备了以Zn O为主体的纳米复合材料Ag/Zn O-Zr O_2。通过X射线粉末衍射(XRD)、紫外-可见漫反射吸收光谱(UV-Vis/DRS)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和N2吸附-脱附等表征手段研究了微波辐射对Ag/Zn O-Zr O_2晶型结构、形貌及表面物理化学性质的影响。结果表明,在200 W微波辐射作用下,该样品晶型结构未发生明显变化,但Ag的衍射峰明显增强,同时,其晶粒尺寸、光吸收性质和表面物理化学性质等方面则发生改变,尤其是样品Ag/Zn O-Zr O_2的形貌呈现了圆形片状结构。分别在紫外和微波辅助条件下对纳米复合材料的光催化性能进行了一系列考察,同时为了进一步评价所合成样品在太阳光作用下的实用价值,又考察了Ag/Zn O-Zr O_2在模拟日光条件下的光催化性能。结果显示,紫外光作用下,纳米复合材料Ag/Zn O-Zr O_2的光催化活性高于市售P25以及未经微波处理的样品,且在微波辅助光催化条件下,其活性有较大程度提高。200 W微波功率下所合成样品Ag/Zn O-Zr O_2在模拟日光作用下显现出较高活性。另外,根据紫外光条件下对光催化活性物种的捕获实验提出了Ag/Zn O-Zr O_2可能的光催化机理。     

圆形片状纳米复合材料Ag/ZnO-ZrO2微波辅助合成与多模式光催化罗丹明B

采用微波辅助结合沉淀法制备了以ZnO为主体的纳米复合材料Ag/ZnO-ZrO₂。通过X射线粉末衍射(XRD)、紫外-可见漫反射吸收光谱(UV-Vis/DRS)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和N2吸附-脱附等表征手段研究了微波辐射对Ag/ZnO-ZrO₂晶型结构、形貌及表面物理化学性质的影响。结果表明, 在200 W微波辐射作用下, 该样品晶型结构未发生明显变化, 但Ag的衍射峰明显增强, 同时, 其晶粒尺寸、光吸收性质和表面物理化学性质等方面则发生改变, 尤其是样品Ag/ZnO-ZrO₂的形貌呈现了圆形片状结构。分别在紫外和微波辅助条件下对纳米复合材料的光催化性能进行了一系列考察, 同时为了进一步评价所合成样品在太阳光作用下的实用价值, 又考察了Ag/ZnO-ZrO₂在模拟日光条件下的光催化性能。结果显示, 紫外光作用下, 纳米复合材料Ag/ZnO-ZrO₂的光催化活性高于市售P25以及未经微波处理的样品, 且在微波辅助光催化条件下, 其活性有较大程度提高。200 W微波功率下所合成样品Ag/ZnO-ZrO₂在模拟日光作用下显现出较高活性。另外, 根据紫外光条件下对光催化活性物种的捕获实验提出了Ag/ZnO-ZrO₂可能的光催化机理。     

纳米复合材料Ag/TiO_2-ZrO_2的制备及其微波增强光催化降解甲基橙

采用EO20PO70EO20(P123)作模板剂,通过溶胶-凝胶-程序升温溶剂热一步法,并经萃取处理制备了具有光催化活性的纳米复合材料Ag/TiO2-ZrO2.用X射线衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)、N2吸附-脱附测定和扫描电子显微镜配合X射线能量色谱仪(SEM-EDS)等测试手段对其组成、结构及形貌等进行了表征.结果表明,复合材料Ag/TiO2-ZrO2中Ag以单质形式存在,材料具有双孔结构,颗粒分布较均匀,结构也较规整,平均孔径约为3.6和9.0nm.通过微波增强光催化降解染料甲基橙的实验,对复合材料Ag/TiO2-ZrO2的光催化活性进行了探究.实验结果表明,微波辅助光催化效果优于紫外辐射,并且萃取后的合成产物Ag/TiO2-ZrO2在90min内对甲基橙的降解率可达81.5%,其活性高于市售P25以及TiO2-ZrO2.     

CTAB作用下纳米复合材料ZnO-TiO2制备与多模式光催化降解罗丹明B

在模板剂十六烷基三甲基溴化铵作用下,通过溶胶-凝胶与程序升温溶剂热法制备了纳米复合材料ZnOTiO2(CTAB).经X-射线衍射(XRD)、紫外-可见漫反射吸收光谱(UV-Vis/DRS)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和N2吸附-脱附测试等手段对其组成、结构和形貌等进行了表征.结果显示,合成产物ZnO-TiO2(CTAB)主要晶型为ZnO纤锌矿,并部分生成ZnTiO3.同时,该合成产物经CTAB作用后,其对光的吸收发生明显红移,且平均孔径明显变小,BET值增大.在紫外光、可见光、模拟日光和微波辅助等不同模式光催化降解罗丹明B的实验研究中,与未经CTAB作用的样品ZnO-TiO2相比,ZnO-TiO2(CTAB)具有更高的光催化性能.同时,该复合材料在紫外光条件下,对甲基橙、罗丹明B、结晶紫、亚甲基蓝和龙胆紫5种不同结构染料的光催化中均表现出良好的降解效果.     

核壳结构纳米Cu_2O/Ag的制备、表征和应用研究

通过溶胶-凝胶法制备了单分散性的球形纳米Cu_2O,采用取代反应法在上面负载一层纳米Ag,制备了核壳结构的Cu_2O/Ag纳米复合材料。利用透射电镜(TEM)分析了纳米Cu_2O/Ag的形貌,并用X射线衍射测(XRD)X射线光电子能谱(XPS)分析了其物相组成,利用紫外-可见光谱(UV-Vis)和光致发光光谱(PL)研究了其光谱特征,以罗丹明B(Rh B)为模型污染物,在紫外光照射下评价了纳米Cu_2O/Ag的光催化活性。结果表明:Cu_2O平均直径为150nm,表面纳米银直径为7nm,形成核壳结构;光催化结果显示,银沉积显著提高了Cu_2O的光催化活性。     

纳米复合材料Ag/ZnO的制备与微波增强光催化二甲酚橙

采用溶胶凝胶再结合程序升温溶剂热法制备了纳米复合材料Ag/ZnO,通过X射线衍射(XRD)、N2吸附-脱附、透射电子显微镜(TEM)以及扫描电子显微镜配合X射线能量色散谱仪(SEM-EDS)等测试手段对其结构、形貌等进行了表征.结果表明,复合材料中Ag以单质形式存在且掺杂于ZnO表面,产物具有六方晶系纤锌矿结构,其颗粒...     

溶剂热法制备Ag/TiO_2纳米材料及其光催化性能

以乙醇为溶剂,钛酸四丁酯为前驱体,用溶剂热法制备了Ag表面修饰的负载型纳米二氧化钛光催化剂.利用X射线衍射(XRD)、N2吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、紫外-可见(UV-Vis)光谱等技术对其进行了系统的表征,以亚甲基蓝(MB)溶液的脱色降解为模型反应,考察了不同Ag含量样品的光催化性能.结果表明:用溶剂热法制备的样品中TiO2皆为锐钛矿相,金属Ag颗粒沉积在TiO2表面,粒径为2nm左右,比表面积较溶胶凝胶法制备的样品大大增加,最高可达151.44m2·g-1;UV-Vis光谱和光催化实验表明:Ag修饰使TiO2对光的吸收能力大大增强,吸收带边红移至可见光区,亚甲基蓝在该复合材料上的光催化降解反应遵循一级反应动力学模型;溶剂热法制备样品的光催化性能明显好于溶胶凝胶法制备的样品,在紫外光和可见光下,Ag摩尔分数为5%的样品表现出最佳的光催化活性.     

ZnO/Ag微米球的合成与光催化性能

用微波辅助多元醇法对预先制备的ZnO微米球进行修饰,合成了载银氧化锌微米球（ZnO/Ag）. 利用X射线衍射仪、场发射扫描电子显微镜、透射电子显微镜、X射线光电子能谱仪、紫外-可见双光束分光光度计和光致发光光谱仪等对样品的结构、形貌和光学性能进行了表征. 在紫外光照射下,通过亚甲基蓝的降解反应研究了样品的光催化活性. 结果表明,所制备的ZnO/Ag微米球是由面心立方的Ag纳米颗粒附着在纤锌矿结构的ZnO球表面形成;与ZnO相比,ZnO/Ag的紫外-可见光吸收光谱发生明显红移,在紫外和可见光范围均有较强的吸收;随着Ag含量的增加,ZnO/Ag荧光光谱强度先减弱后增强;与ZnO相比,ZnO/Ag的光催化活性明显提高,AgNO₃ 浓度为0.05 mol/L时制得的ZnO/Ag光催化活性最高.     

Ag/ZnO/ZnSe三元异质结的合成及其可见光光催化性能

以Ag纳米线为模板,通过两步水浴法合成了Ag/ZnO/ZnSe三元异质结光催化材料。利用场发射扫描电子显微镜(FESEM)、X射线能谱仪(EDS)、X射线衍射仪(XRD)以及透射电子显微镜(FETEM)对样品的形貌和结构进行了表征。结果显示,Ag/ZnO/ZnSe三元异质结为蠕虫状的Ag/ZnO二元异质结外镶嵌着ZnSe小颗粒。在可见光下,对比纯Ag纳米线、纯ZnO纳米球、Ag/ZnO异质结对罗丹明B的可见光降解效率,结果发现Ag/ZnO/ZnSe异质结表现出了更高的光催化效率。其光催化性能的提高主要是由于Ag/ZnO/ZnSe异质结的作用促使电子空穴对的分离,降低了电子空穴对的复合机率,从而提高了材料的光催化效率。     

微波辅助合成纳米复合材料Ag/ZnO-ZnS及其光催化降解若丹明B初步研究

采用微波辅助合成方法制备了具有高光催化活性的纳米复合材料Ag/ZnO-ZnS,经X-射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜配合X-射线能量色散谱仪(SEM-EDS)以及氮气吸附-脱附测定等对合成材料的结构、形貌和表面物理化学性质进行了表征。结果表明,经微波处理后的纳米复合材料Ag/ZnO-ZnS中Ag以单质形式存在,具有纤锌矿晶型结构,属介孔材料,平均孔径约为4.1nm,比表面积更大,颗粒分布更加均匀。通过模型分子若丹明B分别考察了紫外和微波辐射下Ag/ZnO-ZnS的光催化活性,结果显示,微波辅助合成的Ag/ZnO-ZnS具有更高的光催化活性,其在微波增强光催化条件下,40min内对若丹明B脱色率达99%以上,明显高于市售P25等其他体系。     

Microwave‐Hydrothermal Preparation and Visible‐Light Photoactivity of Plasmonic Photocatalyst Ag‐TiO2 Nanocomposite Hollow Spheres

Visible‐light‐driven plasmonic photocatalyst Ag‐TiO₂ nanocomposite hollow spheres are prepared by a template‐free chemically‐induced self‐transformation strategy under microwave‐hydrothermal conditions, followed by a photochemical reduction process under xenon lamp irradiation. The prepared samples are characterized by using scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, N₂ adsorption‐desorption isotherms, X‐ray photoelectron spectroscopy, UV/Vis and Raman spectroscopy. Production of ?OH radicals on the surface of visible‐light illuminated TiO₂ was detected by using a photoluminescence method with terephthalic acid as the probe molecule. The photocatalytic activity of as‐prepared samples was evaluated by photocatalytic decolorization of Rhodamine B (RhB) aqueous solution at ambient temperature under visible‐light irradiation. The results show that the surface plasmon absorption band of the silver nanoparticles supported on the TiO₂ hollow spheres was red shifted, and a strong surface enhanced Raman scattering effect for the Ag‐TiO₂ nanocomposite sample was observed. The prepared nanocomposite hollow spheres exhibits a highly visible‐light photocatalytic activity for photocatalytic degradation of RhB in water, and their photocatalytic activity is higher than that of pure TiO₂ and commercial Degussa P25 (P25) powders. Especially, the as‐prepared Ag‐TiO₂ nanocomposite hollow spheres at the nominal atomic ratio of silver to titanium ( R ) of 2 showed the highest photocatalytic activity, which exceeds that of P25 by a factor of more than 2.     

Zn3(OH)2V2O7·2H2O纳米片的水热制备

采用硝酸锌、五氧化二钒和氢氧化钠作为反应物,通过一个简单的CTAB辅助的水热方法制备了Zn3(OH)2V2O7·2H2O纳米片.运用XRD,ICP-AES,FTIR,HRTEM,EDS,FE-SEM对产物的晶相和形貌进行了表征.结果表明CTAB在控制产物的形貌、尺寸分布和自组装过程中起着关键作用.同时我们研究了产物的晶体生长行为和自组装过程.     

BiOBr的可控制备及对废水中卡马西平的有效降解

以Bi(NO₃)₃·5H₂O为原料, 乙醇为介质, KBr和/或十六烷基三甲基溴化铵(CTAB)为溴源, 采用溶剂热法合成了不同结构和性能的BiOBr微纳米材料, 通过 X射线衍射仪(XRD)、 扫描电子显微镜(SEM)、 红外光谱仪(FTIR)、 紫外-可见漫反射光谱(UV-Vis DRS)及比表面积和孔隙度分析仪对产物进行了表征. 结果表明, 溴源(KBr, CTAB)对BiOBr的结晶特性和形貌有重要影响, 其中采用双溴源且KBr与CTAB摩尔比为3∶7时制得的BiOBr(K∶C=3∶7)光催化剂在模拟太阳光下具有最优的光催化性能, 光照20 min后对废水中卡马西平的降解速率常数是以KBr为溴源制备的BiOBr(K)的4.10倍和以CTAB为溴源制备的BiOBr(C)的2.14倍. BiOBr(K∶C=3∶7)优异的光催化活性可归因于其高暴露的(110)晶面、 表面羟基、 疏松的片层状形貌及较大的比表面积和孔体积. 活性物种淬灭实验结果表明, BiOBr(K∶C=3∶7)的光催化活性主要源于光生空穴、 羟基自由基和电子.     

Photocatalytic degradation of acid blue 74 in water using Ag–Ag2O–Zno nanostuctures anchored on graphene oxide

Water pollution due to industrial effluents from industries which utilize dyes in the manufacturing of their products has serious implications on aquatic lives and the general environment. Thus, there is need for the removal of dyes from wastewater before being discharged into the environment. In this study, a nanocomposite consisting of silver, silver oxide (Ag₂O), zinc oxide (ZnO) and graphene oxide (GO) was synthesized, characterized and photocatalytically applied in the degradation (and possibly mineralization) of organic pollutants in water treatment process. The Ag–Ag₂O–ZnO nanostructure was synthesized by a co-precipitation method and calcined at 400 °C. It was functionalized using 3-aminopropyl triethoxysilane and further anchored on carboxylated graphene oxide via the formation of an amide bond to give the Ag–Ag₂O–ZnO/GO nanocomposite. The prepared nanocomposite was characterized by UV–Vis diffuse reflectance spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electronic microscopy (SEM), energy dispersive X-ray spectrometry (EDX), Fourier transformed infrared spectroscopy (FTIR), and Raman spectroscopy. The applicability of Ag–Ag₂O–ZnO/GO nanocomposite as a photocatalyst was investigated in the photocatalytic degradation of acid blue 74 dye under visible light irradiation in synthetic wastewater containing the dye. The results indicated that Ag–Ag₂O–ZnO/GO nanocomposite has a higher photocatalytic activity (90% removal) compared to Ag–Ag₂O–ZnO (85% removal) and ZnO (75% removal) respectively and thus lends itself to application in water treatment, where the removal of organics is very important.     

Effects of Ag Doping Content and Dispersion on the Photocatalytic and Antibacterial Properties in ZnO Nanoparticles

ZnO nanoparticles(NPs)with different contents of Ag dopants were obtained by one-step solvothermal method.The crystalline structures of the prepared composites were characterized by means of X-ray diffraction(XRD).The morphology and composition of the samples were studied by means of scanning transmission electron microscopy(TEM)5 X-ray photoelectron spectroscopy(XPS)and electron microscopy(SEM).Photoluminescence(PL)spectra have been used to investigate pure ZnO,Ag-ZnO and Ag-ZnO-PVP NPs to determine the effect of composition on PL properties.It was found that the Ag-ZnO samples showed stronger emissions than pure ZnO.The catalytic activity of samples was measured by the degradation rate of R6G,which exhibited that Ag-ZnO nanocomposite demonstrated enhanced photocatalytic activity compared to the pure ZnO NPs.The possible influence factors to the photocatalytic and antibacterial activities of the sample were explored,including Ag contents and dispersion.It was presented that the photocatalytic activity of Ag-ZnO-PVP was better than that of Ag-ZnO and it showed the highest photocatalytic activity with 7%of Ag content.The Ag-ZnO-PVP can kill the Escherichia coli(E.coli)cells.     

Magnetic retrievable Ag/AgBr/ZnFe2O4 photocatalyst for efficient removal of organic pollutant under visible light

In the present work, a visible-light-driven Ag/AgBr/ZnFe₂O₄ photocatalyst has been successfully synthesized via a deposition–precipitation and photoreduction method. The crystal structure, chemical composition, morphology and optical properties of the as-prepared nanocomposites were characterized by X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscope, UV–vis diffuse reflectance spectroscopy and photoluminescence. The photocatalytic activities of the Ag/AgBr/ZnFe₂O₄ nanocomposites were evaluated through the photodegradation of gaseous toluene and methyl orange (MO) under visible light. The results revealed that the as-prepared Ag/AgBr/ZnFe₂O₄ nanocomposite exhibited excellent photocatalytic activity. The degrading efficiency of MO could still reach 90% after four cycles, and the Ag/AgBr/ZnFe₂O₄ nanocomposite could be recycled easily by a magnet. Additionally, the enhanced photocatalytic mechanism was discussed according to the trapping experiments, which indicated that the photo-generated holes (h⁺) and •O₂⁻ played important roles in photodegradation process. At last, a possible photocatalytic oxidation pathways of toluene was proposed based on the results of GC–MS. The Ag/AgBr/ZnFe₂O₄ composites showed potential application for efficient removal of organic pollutant.     

Preparation,characterization and photocatalytic properties of BiOBr/ZnO composites

BiOBr/ZnO composite photocatalysts were prepared by a simple hydrothermal method. The as-prepared samples were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), high-resolution transmission electron microscopy(HRTEM), UV–Vis diffusion reflectance spectroscopy(DRS) and photoluminescence(PL) spectroscopy, respectively. The photocatalytic activities were evaluated by the degradation of methyl blue(MB) under the simulated sunlight irradiation. Among all the samples, the BiOBr/ZnO composite with a mole ratio of 3:1(Bi:Zn) exhibited the best photocatalytic activity. The improvement of photocatalytic activity was mainly attributed to the low recombination ratio of photo-induced electron-hole pairs. The possible photocatalytic mechanism was discussed on the basis of the band structures of BiOBr and ZnO.