水溶性银纳米颗粒的制备及抗菌性能

采用液相还原法, 以单宁酸为还原剂, 聚乙烯吡咯烷酮(PVP)为修饰剂制备出了水溶性的表面修饰Ag纳米颗粒. 通过X 射线粉末衍射仪(XRD)、透射电子显微镜(TEM)、紫外-可见吸收分光光度计(UV-Vis)、傅里叶变换红外(FTIR)光谱仪等对所得样品的形貌和结构进行了表征. 采用肉汤稀释法测试了样品的抗菌性能, 考察了样品在水相中的分散稳定性, 提出了PVP修饰Ag纳米颗粒的形成机理. 结果表明所制备的样品具有Ag的面心立方晶体结构, 平均粒径为15-17 nm. 样品在水相中能长时间稳定分散; 对埃希氏大肠杆菌(E. coli)、金黄色葡萄球菌(S. aureus)具有明显的抗菌作用. 操作简便、条件温和的制备方法易于在工业规模上放大; 试剂无毒, 使得所制备的PVP修饰Ag纳米颗粒作为抗菌剂具有良好的应用前景.     

Efficient photodegradation of methyl orange and bactericidal activity of Ag doped ZnO nanoparticles

In the present work, silver-doped ZnO (Ag–ZnO NPs) with different concentrations of silver ions (0.3, 0.5, 1.0 and 1.5 mol %) were synthesized by using a simple co-precipitation method. The Ag–ZnO NPs were primarily characterized by XRD, FT-IR, SEM, EDS, TEM, UV–Vis. DRS, PL and BET surface area. The XRD analysis of Ag–ZnO NPs shows a wurtzite structure and optimized Ag–ZnO NPs (1.0 mol %) exhibit a lower crystallite size of 15.96 nm than that of bare ZnO (19.07 nm). Optical study shows a decrease in band gap from 3.13 to 2.97 eV as the concentration of Ag ions increases from 0.3 to 1.5 mol%. TEM images reveal the spherical shape particle with sizes ranging between 10 and 15 nm. From the multipoint BET plot, the surface area of Ag–ZnO NPs found 38.06 m²/gwhich is higher than the ZnO NPs (34.48 m²/g). The photocatalytic study demonstrated that the Ag–ZnO NPs (1.0 mol %) has an excellent photodegradation efficiency of Methyl Orange (96.74%)with a 26% increment as compared to bare ZnO (70.47%). Furthermore, the bactericidal activity of Ag–ZnO NPs (1.0 mol %) was investigated against four different bacterial strains. The results explored that the Gram-negative bacteria (E. coli and P. vulgaris) are more sensitive than Gram-positive (S. aureus and B. cereus) to Ag–ZnO NPs. Overall, the anticipated material is economical and reusable for photodegradation and antibacterial activity.     

纳米TiO_(2)光催化抗菌应用的研究进展北大核心CSCD

光催化纳米TiO_(2)以其出色的光催化、化学稳定性以及广谱抗菌性受到科研人员的青睐。然而,其存在的一些问题,如宽带隙、高过电位和光生载流子快速复合等限制了其光催化性能。本文综述了近年来TiO_(2)光催化在抗菌方面的研究进展。对纳米TiO_(2)光催化抗菌作用机理进行了探讨,并讨论了提高TiO_(2)光催化抗菌活性的几种策略,包括进行纳米TiO_(2)结构设计、光的调控、掺杂金属离子、掺杂非金属离子、贵金属修饰和偶联其他材料。改性TiO_(2)光催化剂显著抑制了细菌细胞的生长,在生物医学工程领域具有独特的应用前景。     

稀土Ce掺杂对ZnO结构和光催化性能的影响

采用共沉淀-焙烧法合成了一系列不同含量的稀土Ce掺杂的ZnO光催化剂. 利用傅里叶变换红外(FT-IR)光谱、粉末X射线衍射(XRD)、扫描电镜(SEM)、紫外-可见(UV-Vis)光谱、光致发光(PL)谱等技术对所制备的光催化剂进行了系列表征. 以酸性橙II脱色降解为模型反应, 考察了掺杂不同含量的铈及不同焙烧温度对ZnO的物理结构和光催化脱色性能的影响. 结果表明: 掺入质量分数(w)为2%的铈可以明显改善氧化锌表面状态, 有利于产生更多的表面羟基; 同时可以抑制光生电子与光生空穴(e^-/h⁺)的复合, 显著提高光催化脱色活性和光催化稳定性; 焙烧温度对光催化剂的晶体结构、表面性能和光催化活性产生较大影响, 500 °C的焙烧处理使样品的结晶度较高, 同时催化剂颗粒粒径较细, 表面具有丰富的羟基. 但过高的焙烧温度(600-800 °C)将导致催化剂的物理结构发生恶化, 降低光催化性能.     

稀土Ce掺杂对ZnO结构和光催化性能的影响

采用共沉淀-焙烧法合成了一系列不同含量的稀土Ce掺杂的ZnO光催化剂. 利用傅里叶变换红外(FT-IR)光谱、粉末X射线衍射(XRD)、扫描电镜(SEM)、紫外-可见(UV-Vis)光谱、光致发光(PL)谱等技术对所制备的光催化剂进行了系列表征. 以酸性橙II脱色降解为模型反应, 考察了掺杂不同含量的铈及不同焙烧温度对ZnO的物理结构和光催化脱色性能的影响. 结果表明: 掺入质量分数(w)为2%的铈可以明显改善氧化锌表面状态, 有利于产生更多的表面羟基; 同时可以抑制光生电子与光生空穴(e^-/h⁺)的复合, 显著提高光催化脱色活性和光催化稳定性; 焙烧温度对光催化剂的晶体结构、表面性能和光催化活性产生较大影响, 500 °C的焙烧处理使样品的结晶度较高, 同时催化剂颗粒粒径较细, 表面具有丰富的羟基. 但过高的焙烧温度(600-800 °C)将导致催化剂的物理结构发生恶化, 降低光催化性能.     

Effects of Co Doping on the Growth and Photocatalytic Properties of ZnO Particles

The present work reports on the synthesis of ZnO photocatalysts with different Co-doping levels via a facile one-step solution route. The structural and optical properties were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and UV-Vis diffuse reflectance spectra. The morphology of Co-doped ZnO depends on the reaction temperature and the amount of Co and counter-ions in the solution. Changes with the c-axis lattice constant and room temperature redshift show the replacement of Zn with Co ions without changing the wurtzite structure. Photocatalytic activities of Co-doped ZnO on the evolution of H₂ and the degradation of methylene blue (MB) reduce with the doping of Co ions. As the close ionic radii of Co and Zn, the reducing photocatalytic activity is not due to the physical defects but the formation of deep bandgap energy levels. Photocurrent response experiments further prove the formation of the recombination centers. Mechanistic insights into Co-ZnO formation and performance regulation are essential for their structural adaptation for application in catalysis, energy storage, etc.     

活性炭负载Cu离子掺杂纳米TiO2颗粒的制备及光催化性能

采用溶胶-凝胶法在活性炭(AC)表面负载掺杂Cu离子的TiO2纳米颗粒, 制备负载型掺杂Cu2+-TiO2/AC复合光催化剂, 采用XRD, ESR, FS, UV-Vis和BET等手段对其进行了表征, 通过罗丹明B的光催化降解试验, 分析活性炭载体的比表面积和Cu离子掺杂量对负载型掺杂催化剂光催化活性的影响. 结果表明, Cu以+2价存在, Ti以少量的+3价存在; TiO2纳米颗粒具有量子尺寸效应, 吸光阈值显著蓝移, 并使光谱相应范围向可见光区拓展; 另外, 适量Cu离子的掺杂降低了负载型TiO2/AC的荧光强度. 负载和高温处理没有改变活性炭载体的微观结构. 以AC3为载体和质量分数为3%的Cu离子掺杂所制备的3%Cu2+-TiO2/AC3催化剂的活性最高, 并且该催化剂便于回收, 在重复使用中也表现出很高的光催化活性.     

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.     

TiO2纳米粒子的光催化活性与光伏响应特性研究

TiO2纳米粒子由于其具有良好的化学稳定性、耐光腐蚀性、宽带隙能和大的比表面积等特点而被广泛地应用到光催化降解有机污染物^[1,2]和光催化储能等方面。由于研究手段和研究方法的限制,详细了解催化剂表面光生电荷行为、光谱谱带与催化活性的关系比较困难,而这些关系将为制备高催化活性的光催化剂提供理论基础,由于光催化活性的高低与催化剂的表面性质直接相关,表面光电压谱（SPS）是研究固体材料表面物性和界面间电荷转移过程的有利手段^[3],其为控制光催化机理提供了新的手段。本文利用表面光电压谱方法对系纳米TiO2光催化剂进行了光伏响应测试,发现TiO2的晶型、粒径及表面吸附物对其光催化活性有很大影响。不同性质的表面吸附物可使催化剂表面呈现不同的导电特性,而使其光催化活性不同。利用能带理论和场效应原理对此进行了 合理的解释。     

Antibacterial and Photocatalytic Properties of ZnO Nanoparticles Obtained from Chemical versus Saponaria officinalis Extract-Mediated Synthesis

In the present work, the properties of ZnO nanoparticles obtained using an eco-friendly synthesis (biomediated methods in microwave irradiation) were studied. Saponaria officinalis extracts were used as both reducing and capping agents in the green nanochemistry synthesis of ZnO. Inorganic zinc oxide nanopowders were successfully prepared by a modified hydrothermal method and plant extract-mediated method. The influence of microwave irradiation was studied in both cases. The size, composition, crystallinity and morphology of inorganic nanoparticles (NPs) were investigated using dynamic light scattering (DLS), powder X-ray diffraction (XRD), SEM-EDX microscopy. Tunings of the nanochemistry reaction conditions (Zn precursor, structuring agent), ZnO NPs with various shapes were obtained, from quasi-spherical to flower-like. The optical properties and photocatalytic activity (degradation of methylene blue as model compound) were also investigated. ZnO nanopowders’ antibacterial activity was tested against Gram-positive and Gram-negative bacterial strains to evidence the influence of the vegetal extract-mediated synthesis on the biological activity.     

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纳米颗粒的生物合成法及其抗菌功能

ZnO纳米颗粒（nanoparticles,NPs）的生物合成法具有高效、简易、环境相容性良好等特点,备受研究者的广泛关注。总结了近些年ZnO NPs的生物合成法及其抗菌活性方面的研究进展。     

微波辐射对纳米ZnO材料物理性质与光催化活性的影响

在采用沉淀法制备ZnO的过程中, 用不同功率(100, 150, 200, 250和300 W)的微波辐射ZnO前驱体, 获得了一系列纳米ZnO材料, 并对合成材料的晶型结构、 形貌及表面物理化学性质进行了表征. 结果表明, 与普通沉淀法制备的ZnO相比, 使用微波辐射后ZnO半导体材料的晶型仍为六方纤锌矿结构, 但吸收光谱发生了蓝移或红移, 且比表面积均有不同程度的增加. 同时, 微波辐射功率不同, ZnO形貌差异明显, 并随着微波功率变化分别呈现纳米颗粒、 椭圆形纳米团簇、 纳米片和球状纳米簇等多样化形态. 以罗丹明B为模型分子, 分别在紫外及微波辅助光催化条件下考察了所合成纳米ZnO材料的光催化性能. 结果显示, 经不同功率微波辐射作用后, ZnO的光催化活性均得到了不同程度的提高, 并且明显高于市售P25和未经微波辐射作用的ZnO.     

N-TiO_2/ZnO复合纳米管阵列的掺杂机理及其光催化活性

以ZnO纳米柱阵列为模板,采用溶胶-凝胶法制备出TiO2/ZnO和N掺杂TiO2/ZnO的复合纳米管阵列.扫描电镜(SEM)、X射线光电子能谱(XPS)和紫外-可见漫反射吸收光谱(UV-Vis)的结果表明:两种阵列的纳米管均为六角形结构,直径约为100nm,壁厚约为20nm;在N-TiO2/ZnO复合纳米管阵列中,掺入的N离子主要是以N-Ox、N-C和N-N的形式化学吸附在纳米管表面,仅有少量的N离子以取代式掺杂的方式占据TiO2晶格O的位置;表面N物种形成的表面态能级和取代式掺杂导致带隙的窄化,增强了纳米管阵列的光吸收效率,促进了光生载流子的分离.光催化实验结果表明,N离子的掺杂有利于N-TiO2/ZnO复合纳米管阵列光催化活性的提高.     

Photocatalytic decolouration,degradation and disinfection capability of Ag2CO3/ZnO in natural sunlight

In this study, a series of hybrid Ag₂CO₃/ZnO composites were synthesised via a simple precipitation route and investigated for discolouration-degradation of Methylene Blue and disinfection of Escherichia coli in natural sunlight. It was observed that the photonic efficiency of discolouration was more than 6 times that of the conventionally popular TiO₂, under experimental conditions; 100% Total Organic Carbon reduction was observed in 30 ?min and 32% disinfection in an hour. This upswing in the performance is attributed to favourable modulation of the dynamics of charge transfer. The photocatalysts were characterized by X-Ray Diffraction, Scanning Electron Microscopy, Transmission Electron Microscopy, Brunauer, Emmett and Teller and Ultraviolet–Visible-Near-InfraRed Spectroscopy. An equitable photocatalyst functional mechanism has also been proposed on the basis of Tauc plot and scavenging experiments. The effect of influencing parameters has also been investigated and reported in terms of photonic efficiency. Since the entire study is carried out in direct sunlight, it inherently supports realizable solar energy applications in wastewater treatment.     

Antibacterial cotton fabric with in situ generated silver nanoparticles by one-step hydrothermal method

The cotton fabrics were immersed in 1–5?mM aqueous silver nitrate solutions maintained at 80°C for 24?h to in situ generate silver nanoparticles. The presence of silver nanoparticles in the nanocomposite films was proved by microscopic observation. Fourier transform infrared spectra indicated the role of hydroxyl and carboxyl groups of cotton fabric in reducing the silver salt to nanosilver. The nanocomposite cotton fabrics showed good antibacterial activity against Gram-negative and Gram-positive bacteria. The antibacterial cotton fabrics can be considered for medical applications such as surgical aprons, wound cleaning, and dressing.     

铕掺杂对纳米TiO2的光催化活性的影响

用溶胶-凝胶法制备了掺杂Eu3+的纳米TiO2,用XRD和TG-DTA对其进行了表征,并以正庚烷为气相有机污染物的实例研究了样品的光催化活性,发现Eu3+进入TiO2晶格中引起了TiO2晶格膨胀,导致晶格畸变增大,抑制了TiO2晶相的转变和粒径的增长.结果表明,Eu3+掺杂可提高TiO2的光催化活性,并且当掺杂摩尔分数为0.3%时,光催化活性最好.随着焙烧温度的升高,光催化活性下降,而利用较高的水解酸度则有利于得到光催化活性较高的样品.     

氧化铁在ZnO上分散的结构状态及其表征

采用（ＮＨ_４）_３［Ｆｅ（Ｃ_２Ｏ_４）_３］·ｘＨ_２Ｏ的水溶液含浸，Ｆｅ（ＮＯ_３）_３．９Ｈ_２Ｏ水溶液饱和浸渍（含浸）以及Ｆｅ（ＡｃＡｃ）_３的甲苯溶液热吸附三种方法制备了在ＺｎＯ上分散的氧化铁体系。用多种物理化学手段对用不同方法制备的分散体系进行了细致的表征，氧化铁在ＺｎＯ上形成单层分散是困难的。Ｆｅ~（３＋）一般进入到ＺｎＯ载体的表层，结构环境类似于ＺｎＦｅ_２Ｏ_４微晶中的Ｆｅ~（３＋），分散的Ｆｅ~（３＋）通常处于高自旋态，配位对称性并不是正交畸变。在ＺｎＯ上形成尖晶石的趋势最强。在亚单层铁含量范围内，通常形成表面ＺｎｘＦｅ_ｙＯ_ｚ。当铁含量超过单层阈值时，既生成ＺｎＦｅ_２Ｏ_４簇也有ＦｅＯ_ｘ簇存在。无论是ＦｅＯ_ｘ或ＺｎＦｅ_２Ｏ４簇还是表面的Ｚｎ_ｘＦｅ_ｙＯｚ，其Ｆｅ_（３＋）在实验温度范围内，很难被还原为零价铁，ＦｅＯ_ｘ较之Ｚｎ_ｘＦｅ_ｙＯ_ｚ物种难以还原且比体相ａ－Ｆｅ_２Ｏ_３中Ｆｅ~（３＋）要难还原得多。由热吸附法制得的ＦｅＯ_ｘ和ＺｎＦｅ_２Ｏ_４簇具有很低的催化活性，而由含浸法制得的表面Ｚｎ_ｘＦｅ_ｙＯｚ的反应性能有明显的改善。ＺｎＯ载体上不同含铁物种的反应性由Ｆｅ~（３＋）的还原性及是否存在活泼     

凝胶网格控制合成纳米ZnO及其光催化活性

以明胶为反应介质,采用凝胶网格控制合成法制备了单分散球形纳米ZnO光催化剂.利用TG-DTA、XRD、TEM、BET、UV-Vis、HPLC等测试手段对制备过程、样品的结构和性能进行了研究,探讨了明胶浓度、煅烧温度对产物粒径和光催化活性的影响.结果表明:利用凝胶网格控制合成法不仅能够控制纳米微粒的形状和大小,而且可防止沉淀物相互聚集和团聚.以染料罗丹明B溶液为目标降解物,1 h的降解率为99.9%,最佳光催化剂的合成条件:13%明胶浓度、350℃煅烧2 h.     

Pd/ZnO和Ag/ZnO复合纳米粒子的制备、表征及光催化活性

 用焙烧前驱物碱式碳酸锌的方法制备了ZnO纳米粒子，采用光还原沉积贵金属的方法制备了Pd／ZnO和Ag／ZnO复合纳米粒子，并利用ICP，XRD，TEM和XPS等测试技术对样品进行了表征，初步探讨了贵金属在ZnO纳米粒子表面形成原子簇的原因．以光催化氧化气相正庚烷为模型反应，考察了样品的光催化活性以及贵金属沉积量对催化剂活性的影响．结果表明：沉积适量的贵金属，ZnO纳米粒子光催化剂的活性大幅度提高．同时，深入探讨了表面沉积贵金属的ZnO纳米粒子光催化剂活性有所提高的内在原因．