纳米氧化锌光催化降解有机染料性能的研究

用自制的纳米ZnO在室外阴天、太阳光照射、室内紫外灯照射等条件下对不同有机染料的降解性能作了系统的研究。结果表明纳米ZnO在太阳光照射条件下对弱碱性有机染料溶液的降解效果较好。本文还比较了自制纳米ZnO与纳米TiO2对有机染料的降解性能，结果表明ZnO的降解效果优于TiO2。     

均相沉淀法合成纳米ZnO及其光催化性能研究

以ZnSO_4、尿素为原料，采用均相沉淀法在90 ℃合成出了纳米ZnO，并就反应 温度、反应时间、反应物浓度及物料配比等条件对产物的影响进行了探讨。XRD物 相分析，产物为六方晶系；TEM形貌观察，粒子基本为球形，平均粒径20 nm；并用 IR，TG-DTA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 性能，发现纳米氧化锌对200～380 nm波长范围的光有很强吸收性，在可见光范围 内，也有较强的吸收。利用纳米氧化锌作为光催化剂对有机染料溶液进行了降解实 验，发现在日光照射60 min后，对酸性大红4BE的降解率可达100%。     

均相沉淀法合成纳米ZnO及其光催化性能研究

以ZnSO_4、尿素为原料，采用均相沉淀法在90 ℃合成出了纳米ZnO，并就反应 温度、反应时间、反应物浓度及物料配比等条件对产物的影响进行了探讨。XRD物 相分析，产物为六方晶系；TEM形貌观察，粒子基本为球形，平均粒径20 nm；并用 IR，TG-DTA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 性能，发现纳米氧化锌对200～380 nm波长范围的光有很强吸收性，在可见光范围 内，也有较强的吸收。利用纳米氧化锌作为光催化剂对有机染料溶液进行了降解实 验，发现在日光照射60 min后，对酸性大红4BE的降解率可达100%。     

放射性洗涤废水的SDBS光催化降解研究

光催化氧化是处理含表面活性剂放射性洗涤废水的新途径。本文采用臭氧/纳米二氧化钛光催化的方法,对十二烷基苯磺酸钠(SDBS)进行降解研究,考察了SDBS溶液初始浓度、溶液pH、光照时间、臭氧通入量、反应温度等因素对其降解效果的影响。并添加裂片核素~(90)Sr~(2+)和~(137)Cs~+,评价本方法对含SDBS的放射性洗涤废水的降解效果。结果表明,采用臭氧/纳米二氧化钛光催化系统对于300mg·L~(-1)的SDBS溶液进行降解,30分钟SDBS的去除率可达99. 95%,且放射性核素~(90)Sr~(2+)、~(137)Cs~+的同时存在对O_3/纳米TiO_2光催化降解SDBS的性能几乎不影响; FT-IR测试结果表明不同浓度的SDBS的去除率,皆与反应时间正相关关系。     

基于纳米ZnO/聚氯乙烯的复合材料光催化性能研究

本文采用纳米氧化锌与聚氯乙烯溶液共混制备了复合材料前驱体，运用TG-DTA联机分析得到了其分解温度及相关热分解数据；经适当温度煅烧后得到复合材料光催化剂，并用TEM、XRD、FTIR、UV-Vis、ESR对复合材料进行分析表征。在室内普通照明用荧光灯作用下，以甲基橙溶液为催化对象，对复合材料的光催化性能进行了检测，并在相同条件下，与纳米氧化锌、纳米氧化钛及聚氯乙烯直接煅烧产物的光催化性能进行了比对分析；同时研究了pH值对复合材料光催化性能的影响。研究结果表明，复合材料对甲基橙催化降解8 min后，甲基橙溶     

Fe3O4@Cu2O纳米粒子的制备及其催化性能研究

利用室温液相还原、晶种生长的方法,成功的制备了大小形貌均一、性能稳定且具有磁性的Fe3O4@Cu2O复合纳米粒子,并且对制备的Fe3O4@Cu2O纳米粒子进行了光催化性能的研究.在以紫外光为光源的照射下,合成的Fe3O4@Cu2O纳米粒子对有机染料甲基蓝溶液起到很好的降解作用.更重要的是,在外加磁场的作用下,Fe3O4@Cu2O纳米粒子容易回收,具有良好的可循环利用性能.     

基于纳米ZnO/聚苯乙烯的复合材料光催化性能研究

通过将聚苯乙烯与纳米氧化锌前驱体共混制备了复合材料前驱体,运用TG-DTA联机分析得到了其分解温度及相关热分解数据;前驱体经适当温度煅烧后得复合材料光催化剂,运用TEM、XRD、FT-IR、UV-Vis、ESR等测试手段进行了表征。在荧光灯作用下对复合材料光催化性能进行了检测,并与相同条件下纳米氧化锌的光催化性能进行了比对分析。结果表明,该复合材料在荧光作用下对甲基橙催化降解11h后,甲基橙的降解率为35%,与纳米氧化锌催化降解甲基橙5%的降解率相比有较大程度的提高。     

氧化锌包覆超细二氧化钛的制备及其紫外屏蔽性能

采用分步－均一沉淀法，以尿素为沉淀制备粒径为４０ｎｍ的锐钛矿型二氧化钛超细粒子，并在其表面包覆晶体粒径为１０．２ｎｍ的氧化锌，研究了不同含量的氧化锌对包覆效果及紫外吸收性能的影响。结果表明，合成的氧化锌包覆超细说钛矿型ＴｉＯ２的紫外吸收性能明显高于锐钛矿型超细二氧化钛、金红石型二氧化钛及市场氧化锌。     

低温水热法制备高活性纳米金红石相二氧化钛

采用低温水热法由TiC l3溶液直接制备了纳米二氧化钛,并研究了TiC l3溶液浓度、反应温度以及陈化时间对产物晶相、晶化程度、形貌以及尺寸的影响。结果表明:TiC l3溶液浓度对晶相有较大影响,高浓度下易获得混晶,低浓度下得到纯金红石相。反应温度和陈化时间主要影响产物的晶化程度和晶体的形貌、尺寸,对生成的晶相也有一些影响。在给定的反应条件下,获得了形状规整、尺寸约为15×80nm、晶化程度高的金红石相二氧化钛纳米棒。对甲基橙的光催化降解实验表明,这种金红石纳米颗粒的催化活性与市售纳米锐钛矿相二氧化钛相近。     

氧缺陷型SnO2纳米颗粒可见光催化性能的研究

由简单的水热法合成了一种可高效降解有机染料的氧缺陷型Sn O2纳米颗粒新型光催化剂,用X射线衍射、透射电镜、高分辨透射电镜和紫外-可见分光光度计等手段对其结构及性能进行了表征。结果表明,所制备的催化剂的禁带宽度最小可达2.90e V,可实现对可见光的有效吸收利用,对甲基橙的降解反应具有很高的光催化活性。将该催化剂(1g/L)分散在10mg/L的甲基橙溶液中,可见光照射下,40min内甲基橙的降解率达99%以上。由于该催化剂具有合成方法简单、高效、成本低和反应条件温和等特点,为有效解决有机染料对环境的污染问题提供了一条新的途径。     

纳米TiO_2-ZnO二元负载木材的制备及性质

采用两步法将TiO_2/ZnO纳米材料与杨木试样复合,制备了纳米二元负载木材.通过X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)和扫描电子显微镜(SEM)对样品的结构和形貌进行了表征,并探讨了不同处理条件下得到的纳米氧化物负载木材及非纳米氧化物负载木材的抗菌性和耐候性.结果表明,氧化锌和二氧化钛二元协同负载木材的抗菌性和耐候性均优于单一纳米晶处理的木材;在溶剂热反应中以正己烷作为溶剂所制备样品的性能优于以水和无水乙醇为溶剂制备的样品;并且纳米结构负载木材的抗菌性和耐候性优于非纳米结构负载的木材.     

Large-scale synthesis of ZnO balls made of fluffy thin nanosheets by simple solution process: structural, optical and photocatalytic properties

This paper reports a large-scale synthesis of ZnO balls made of fluffy thin ZnO nanosheets by simple solution process at low-temperature of 65±2°C. The synthesized ZnO structures were characterized in detail in terms of their morphological, structural, optical and photocatalytic properties. The detailed morphological characterizations, done by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), confirmed that the synthesized products are ZnO balls which are made by accumulation of hundreds of thin ZnO nanosheets. Interestingly, it is seen that the nanosheets are arranged in such a special fashion that they made ball-like morphologies. Detailed structural examinations revealed that of as-synthesized ZnO products are well-crystalline and possessing wurtzite hexagonal phase. The optical property, measured by UV-Visible spectroscopy, substantiated good optical properties for as-synthesized ZnO balls. The as-synthesized ZnO balls were utilized as an efficient photocatalysts for the photocatalytic degradation of methylene blue (MB) dye. Almost complete degradation of MB was observed in presence of ZnO balls composed of nanosheets within 70 min under UV-light irradiation. By comparing the photocatalytic performance with commercially available TiO(2)-UV-100, it was observed that the synthesized ZnO balls exhibited superior photocatalytic performance as compared to TiO(2)-UV-100 photocatalyst.     

Influence of operational parameters on photocatalytic degradation of a genotoxic azo dye Acid Violet 7 in aqueous ZnO suspensions

The photocatalytic degradation of a genotoxic azo dye Acid Violet 7 (AV 7) using ZnO as a photocatalyst in aqueous solution has been investigated under UV irradiation. The degradation is higher with UV/ZnO process than with UV/TiO(2)-P25 process at pH 9. The effects of different parameters such as pH of the solution, amount of catalyst, initial dye concentration and the influence of cations, anions and oxidants on photodegradation of AV 7 were analyzed. Addition of oxidants except H(2)O(2) has no significant effect on degradation. The degradation of AV 7 follows pseudo-first order kinetics according to the Langmuir-Hinshelwood model. The degradation of AV 7 has also been confirmed by COD and CV measurements.     

Fabrication of urchin‐like Ag/ZnO hierarchical nano/microstructures based on galvanic replacement mechanism and their enhanced photocatalytic properties

Urchin‐like Ag/ZnO hierarchical nano/microstructures have been synthesized through a facile low‐temperature hydrothermal growth method based on galvanic replacement mechanism. The experimental results show that the urchin‐like Ag/ZnO heterostructures are formed through the epitaxial growth of ZnO nanorods on the {111} facets of Ag nanoparticles along their own c‐axis. The photocatalytic properties of the products were evaluated by the degradation of RhB dye solution under ultraviolet irradiation, and the results show that the products exhibit significantly enhanced photocatalytic properties comparing with pure ZnO nanorods. The products with a Ag content of 35.64 atom % prepared with a Ag⁺ concentration in solution of 5 mM exhibit surprisingly high degradation rate (99.5%) for RhB dye solution (4 mg/L) after photocatalytic reaction for only 14 min under ultraviolet irradiation. The Schottky barrier formed at the metal‐semiconductor interfaces improves the segregation of charges and prevents the charge recombination, and thus significantly enhances the photocatalytic activities of the products. On the other hand, the high stability of the urchin‐like Ag/ZnO hierarchical nano/microstructures can effectively prevent the aggregation of nanostructures with simultaneously preserving high photocatalytic properties due to the existence of nanosized unites. Copyright © 2016 John Wiley & Sons, Ltd.     

Efficient photoinduced conversion of an azo dye on hexachloroplatinate(IV)-modified TiO2 surfaces under visible light irradiation-A photosensitization pathway

The titanium dioxide photocatalyst is employed to examine the influence of chemisorbed hexachloroplatinate(IV) anions (PtCl(6) (2-)) on the surface of P-25 TiO(2) particles on the photoinduced conversion of the azo dye Ethyl Orange (EO) in visible light-illuminated Pt(IV)/TiO(2) dispersions. Spin-trap electron spin resonance (ESR) spectral results, measurement of quantities of organoperoxides formed, total organic carbon (TOC) and chemical oxygen demand (COD(Cr)) assays, together with XPS evidence show that the self-sensitized transformation dynamics of the EO dye mediated by Pt(IV)/TiO(2) are much faster than those occurring on naked TiO(2) under otherwise identical conditions of visible light irradiation. X-ray photoelectron spectral data also show that under the experimental conditions used, no Pt(0) formed on the titania particles during visible light irradiation. We propose a reaction mechanism in which the more rapid conversion of EO in the presence of PtCl(6) (2-) is caused principally by photoexcitation of the dye and not by localized excitation of the tetrachloroplatinate(IV)/TiO(2) particles.     

染料在纳米TiO2薄膜表面吸附性能的研究

采用溶胶－凝胶法制备纳米TiO2薄膜，并通过吸附染料形成染料／TiO2复合薄膜。分析了染料与TiO2薄膜的相互关系，利用紫外可见、比表面等技术研究染料在纳米TiO2薄膜表面的吸附性能，并计算出TiO2薄膜对染料的最大吸附率。研究表明，染料溶液浓度、温度以及TiO2薄膜浸泡时间对染料吸附量有着显著的影响，染料的吸附性能直接影响着太阳能电池的光电转换效率。     

SiO2负载的TiO2光催化剂可见光催化降解染料污染物

 采用酸催化溶胶-凝胶法制备了SiO2负载的TiO2光催化剂,考察了制备条件对负载型TiO2光催化剂的晶相、结构、比表面积和可见光催化活性的影响. 结果表明,采用SiO2为载体时,TiO2以纳米颗粒的形态分散在载体表面,负载型TiO2/SiO2催化剂的比表面积大、等电点低而且热稳定性能良好. 偶氮染料酸性橙7的可见光催化降解实验结果表明,染料污染物在催化剂表面的吸附是影响催化剂可见光催化活性的重要因素. 与试剂TiO2样品相比,负载型TiO2/SiO2光催化剂具有更好的光催化活性和沉降性能.     

纳米TiO2-免疫-电生孔复合技术光催化氧化杀伤LoVo肠癌细胞的机理

纳米TiO2光催化氧化-免疫-电生孔复合技术能够在低的纳米TiO2浓度条件下(3.12 μg·mL-1)高效选择性地杀伤LoVo肠癌细胞. 在光强为4 mW·cm-2的紫外光(波长253.7 nm)照射下, 30 min内可全部杀死癌细胞. 利用共聚焦荧光显微镜、透射电镜(TEM)和单细胞凝胶电泳的方法研究了其作用过程. 结果表明, 经抗体修饰的纳米TiO2微粒能自动吸附在癌细胞的细胞膜上, 在电脉冲作用下纳米TiO2可进入细胞内部, 并主要集中在细胞核区域. 在紫外光的照射下, 基于纳米TiO2的光催化氧化作用, 造成细胞内一些细胞器、核膜和核中DNA的损伤, 使细胞坏死. 由于是在细胞内部产生光催化氧化作用, 显著提高了杀伤LoVo肠癌细胞的能力.     

Hybrid junctions of zinc(II) and magnesium(II) phthalocyanine with wide-band-gap semiconductor nano-oxides: spectroscopic and photoelectrochemical characterization

The optical properties of zinc phthalocyanine (ZnIIPc) and magnesium phthalocyanine (MgIIPc) in DMSO and DMF solutions have been extensively investigated, and the photoelectrochemical behaviors of layer-by-layer hybrid junctions formed of the two metallo(II) phthalocyanines (MIIPcs) and wide-band-gap colloidal semiconductors, namely, ZnO and TiO2 nanocrystals (NCs), have been probed. Different experimental conditions, such as the Pc center metal ion, dye concentration, and solvent identity, were investigated in order to elucidate their effects on the photoelectrochemical performances of the prepared heterojunctions. Finally, thermal treatment of either dye and NC films and control of the NC shape and surface chemistry were also studied and, interestingly, were found to be critical in affecting the performance of photochemical sensitization processes, occurring at the dye/oxide and oxide/solution interfaces.     

Use of titanium dioxide photocatalysis on the remediation of model textile wastewaters containing azo dyes

The photocatalytic degradation of two commercial textile azo dyes, namely C.I Reactive Black 5 and C.I Reactive Red 239, has been studied. TiO(2) P25 Degussa was used as catalyst and photodegradation was carried out in aqueous solution under artificial irradiation with a 125 W mercury vapor lamp. The effects of the amount of TiO(2) used, UV-light irradiation time, pH of the solution under treatment, initial concentration of the azo dye and addition of different concentrations of hydrogen peroxide were investigated. The effect of the simultaneous photodegradation of the two azo dyes was also investigated and we observed that the degradation rates achieved in mono and bi-component systems were identical. The repeatability of photocatalytic activity of the photocatalyst was also tested. After five cycles of TiO(2) reuse the rate of colour lost was still 77% of the initial rate. The degradation was followed monitoring the change of azo dye concentration by UV-Vis spectroscopy. Results show that the use of an efficient photocatalyst and the adequate selection of optimal operational parameters may easily lead to a complete decolorization of the aqueous solutions of both azo dyes.