工业钛液制备二氧化钛前驱体及影响因素研究

以工业钛液为原料水热合成出Ti O2前驱体。用XRD、粒度分布、FT-IR对样品进行了表征,并以亚甲基蓝光催化降解体系评价了其光催化活性。研究结果表明,随着工业钛液浓度的增大,前驱体的晶粒尺寸无明显变化,粒度总体上呈减小的趋势。衍射结果表明前驱体已经具有锐钛型结构,这使得其具有一定光催化活性,由于未经热处理,结晶度较低,光催化活性较低。     

煅烧温度对工业钛液制备多孔二氧化钛的影响

以工业硫酸钛液为前驱体,采用水热法制备多孔二氧化钛,考察了煅烧温度对多孔二氧化钛结构和性能的影响。采用XRD、SEM、BET对样品进行表征,并以亚甲基蓝光催化降解体系评价其光催化活性。随着煅烧温度的延长多孔二氧化钛的比表面积逐渐降低,晶粒尺寸逐渐增大,光催化活性先增加后降低,其中以450℃煅烧1h所得样品催化活性最佳,1h对亚甲基蓝的降解率为80．19％,其比表面积93．3m2／g,晶粒尺寸16．48nm。     

大理石废料水热法制备高白度碳酸钙粉体及其晶形控制

以大理石废料为原料,采用碱溶液中水热处理工艺,制备高白度碳酸钙粉体.利用X射线粉末衍射、透射电镜和粉体白度测试仪,分析碳酸钙粉体晶体结构、晶粒形貌以及粉体白度,研究晶形控制剂对碳酸钙粉体白度、晶粒形状和尺寸的影响.结果 表明,添加CaF2时碳酸钙粉体为球形和片状晶粒,添加Na2 SO4时粉体主要为棒状晶粒,添加ZnSO4时粉体为片状和板状晶粒.碳酸钙粉体白度随CaF2含量增加以及水热温度升高,呈现先增大后减小趋势.180℃水热条件下添加3％ CaF2时,碳酸钙粉体白度达到最大值96.7％.随着水热温度升高,碳酸钙粉体晶粒尺寸先减小后增大,160℃时平均粒径达到最小值143 nm.     

Zr掺杂对BaTiO3陶瓷微观形貌及性能的影响

采用溶胶-凝胶法制备了锆掺杂的钛酸钡陶瓷,通过XRD、SEM等分析检测手段对所得锆钛酸钡陶瓷样品进行了表征。系统地研究了Zr掺杂对BaTiO_3基陶瓷相组成、微观形貌和介电性能的影响。结果表明,锆钛酸钡陶瓷样品均为单一的立方相钙钛矿结构,晶粒大小均匀,随着Zr掺杂量的增加,陶瓷晶粒尺寸先增大后减小,孔隙逐渐增多,介电常数先增大后减小,介电损耗先减小后增大。     

溶胶-凝胶自燃烧法制备纳米CoYxFe2-xO4铁氧体的特性

采用溶胶-凝胶自燃烧法制备了CoYxFe2-xO4(x=0.0,0.1,0.2,0.3)铁氧体纳米粉末,并在不同温度下对样品进行了热处理.利用热重/差热综合分析仪及Fourier变换红外光谱仪研究样品的热反应过程.利用X射线衍射仪和振动样品磁强计对样品的结构、晶粒尺寸和磁性进行了测量和分析.结果表明:经自燃烧和不同温度热处理后粉末样品都具有尖晶石结构,晶粒尺寸为10～22 nm之间,存在亚铁磁性.随着稀土钇掺杂量的增加,晶格常数呈现变小趋势,晶粒尺寸减小,矫顽力增大,比饱和磁化强度减小,样品形成单相尖晶石结构能力变弱.经过热处理后,样品的晶格常数、晶粒尺寸、比饱和磁化强度增加,而矫顽力先增后减.     

SAS对镍铝水滑石材料超级电容性能的影响

减小电极活性物质晶粒和颗粒尺寸对提高电化学性能具有重要作用.采用共沉淀法通过控制十二烷基磺酸钠(SAS)的添加量合成镍铝水滑石(NiAl-LDHs)电极材料,通过X射线衍射仪、扫描电镜表征电极材料的晶粒尺寸和颗粒尺寸形态,通过电化学工作站测试电化学性能,研究发现:随着SAS添加量增大,镍铝水滑石晶粒尺寸逐渐减小,SAS添加8 mmol时最小,达到2.2 nm;颗粒随着SAS增加更为疏松,尺寸逐渐减小,团聚趋势减小.比电容随着SAS加入量增大逐渐增大.添加SAS 8 mmol的样品在电流密度1 A/g时具有最大比电容953 F/g,在5 A/g电流密度下循环1000圈后比电容仍保持初始值的45.8％,表现出较好的电化学性能.     

占空比对Ni-WC纳米复合镀层耐蚀性及硬度的影响

采用脉冲电沉积法在304不锈钢基体上制备出Ni-WC纳米复合镀层,并研究了占空比对Ni-WC纳米复合镀层耐蚀性及硬度的影响。结果表明:随着占空比的增大,Ni-WC纳米复合镀层的平均晶粒尺寸先减小后增大,硬度先增大后减小;当占空比为50%时,Ni-WC纳米复合镀层的平均晶粒尺寸最小,耐蚀性最好,硬度最大。     

稀土掺杂混晶TiO2薄膜的制备和性能

利用溶胶-凝胶法在瓷片表面制备了纯的和少量Eu3 掺杂的TiO2薄膜,并用X-射线衍射技术对样品进行了表征。研究了少量Eu3 掺杂对样品相结构、晶粒尺寸和光催化降解亚甲基蓝活性的影响。利用相结构与TiO2薄膜光催化活性关系,探讨了少量Eu3 掺杂对TiO2薄膜的光催化活性的影响。结果表明,与纯TiO2薄膜相比,适量掺杂Eu3 可以显著提高其光催化活性。当Eu3 的质量分数为0.02%,TiO2薄膜的光催化活性最佳,降解率为62%,金红石相质量分数为17.2%,平均晶粒粒径为20 nm;Eu3 掺杂强烈地抑制TiO2由锐钛矿相向金红石相的转变并减小了晶粒尺寸,有利于提高光催化活性。     

预涂镧盐的二氧化钛薄膜制备和性能

在玻璃表面预涂一层硝酸镧掺杂的TiO2薄膜.研究了镧盐掺杂对样品相结构、晶粒尺寸和光催化降解亚甲基蓝活性的影响.利用相结构与TiO2薄膜光催化活性关系,探讨了镧盐掺杂对TiO2薄膜的光催化活性的影响.结果表明,与纯TiO2薄膜相比,适量掺杂镧盐可以显著提高其光催化活性.当预涂w(硝酸镧)为0.3%溶液时,TiO2薄膜的光催化活性最佳,降解率为94.56%,镧盐强烈地抑制TiO2由锐钛矿相向金红石相的转变,减小晶粒尺寸,这两方面均有利于提高光催化活性.     

几种类型纳米TiO2的制备及光催化活性研究

通过水解-沉淀法制备出一系列I和Fe掺杂纳米TiO2粉体。掺杂TiO2的物理性质通过XRD、UV-vis漫反射表征,光催化活性通过对MB的光催化降解来表征。讨论了不同掺杂元素对TiO2的晶型、晶粒尺寸、光响应程度及光催化活性的影响。结果表明掺杂可以减小晶粒尺寸,增加TiO2的紫外光和可见光响应程度和提高TiO2光催化活性。     

Cu掺杂BiVO4光催化剂的水热合成及其光催化性能研究

以硝酸铋、偏钒酸铵、硝酸铜、氢氧化钠、硝酸等为主要原料,采用水热法合成Cu掺杂BiVO₄光催化剂。主要研究了Cu的掺杂量对合成BiVO₄光催化剂性能的影响。采用XRD、SEM、BET、紫外-可见分光光度计等检测仪器对合成试样的物相组成、微观形貌、比表面积及光催化性能进行了表征。结果表明:Cu掺杂改变了合成产物的物相组成,产物中出现Bi₂O₃、V₂O₅等杂质,并且产物的形貌发生了较大变化。光催化降解亚甲蓝结果表明,随着Cu掺杂量的增加,合成光催化剂的光催化性能呈现先增加后减小趋势,当Cu掺杂量为5 wt%时,合成产物的光催化性能达到最佳,在高压汞灯照射240 min时,对亚甲蓝(10 mg/L)的降解率达87.8%,比同条件下纯BiVO4的光催化效率提高16.4%。     

利用Sol-Gel法与水热合成法制备纳米TiO2及其光催化活性研究

以Sol-Gel法及水热合成方法制备了纳米TiO2,利用XRD进行了表征,以太阳光为光源,通过对亚甲基蓝溶液的降解反应,考察了两种方法所得样品的光催化活性。结果表明,利用水热合成法制备的锐钛矿型TiO2具有更小的粒径,而通过溶胶-凝胶制得的样品为混晶型TiO2,对亚甲基蓝降解具有较高的光催化活性。     

La3+掺杂对BiPO4光催化活性的影响

采用一步水热合成法制备La3+掺杂BiPO4纳米粉末,利用XRD、EDS、SEM、BET、UV-Vis、XPS等手段对La3+-BiPO4的形貌、结构、光谱特征、表面化学组成等做了表征和分析。以亚甲基蓝为目标污染物,考察了La3+-BiPO4的催化活性,并探讨了La掺杂提高BiPO4光催化性能的机理。结果表明：La掺杂使纳米BiPO4的晶粒生长受到抑制,比表面积增加,带隙变宽,出现氧空位,光生电子-空穴对复合几率降低。La3+-BiPO4光催化活性明显高于未掺杂的BiPO4,紫外光照射下,90 min 内,2% La3+-BiPO4对亚甲基蓝的降解率可达95%,光催化反应速率是BiPO4的3.7倍。     

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。     

Enhanced photocatalytic activity of Au-buffered TiO2 thin films prepared by radio frequency magnetron sputtering

Au-buffered TiO₂ thin films have been prepared by radio frequency magnetron sputtering method. The structural and morphological properties of the thin films were characterized by X-ray diffraction, scanning electron microscopy, and atomic force microscopy. The photocatalytic activity of the samples was evaluated by the photodecomposition of methylene blue. The Au-buffer thin layer placed between the TiO₂ thin films significantly enhanced photocatalytic activity by 50%. Annealing the Au-buffered TiO₂ thin film at 600 °C decreased the film roughness, but it increased the surface area and anatase crystalline size, enhancing the photocatalytic activity.     

半纤维素/TiO2复合凝胶的光催化降解性能

以半纤维素和TiO₂纳米粒子为原料制得半纤维素/TiO₂复合凝胶。分别用红外光谱分析和扫描电镜对复合水凝胶进行了表征,分析表明半纤维素上成功接枝聚丙烯酸,凝胶呈现多孔结构,且随着TiO₂含量的增加凝胶孔径减小。考察了半纤维素/TiO₂复合凝胶的溶胀性能以及对亚甲基蓝的光催化降解性能,研究表明半纤维素/TiO₂复合凝胶的溶胀率随着TiO₂粒子含量的增加而减小,随着pH的增大先增大后减小;对亚甲基蓝染料的降解率随着TiO₂含量的增加先增大后减小,随着pH的增大先增大后减小,随着亚甲基蓝初始浓度的增大而增大。     

Ag-doped nickel ferrites and their composite with rGO: Synthesis,characterization, and solar light induced degradation of coloured and colourless effluents

Nickel ferrites (NF), silver doped nickel ferrites (AgNF), and a composite of silver doped nickel ferrites with reduced graphene oxide (AgNF@rGO) were prepared through the co-precipitation method. The X-ray diffraction analysis was carried out to confirm the structure of prepared materials, and the crystallite size of prepared ferrites was less than 10 nm. FT-IR spectroscopy was performed for the confirmation of functional groups present in the synthesized materials. The surface morphology of prepared samples was investigated via scanning electron microscopy. Optical analysis was carried out with the help of UV–Visible spectroscopy. Thermogravimetric analysis was performed to check the thermal stability. The photocatalytic degradation of methylene blue under solar light irradiation was studied. The AgNF@rGO composite showed 76% degradation of coloured compound (methylene blue) and 50% degradation of colourless compound (benzimidazole). The enhanced photocatalytic degradation efficacy of AgNF@rGO was ascribed to the reduced graphene oxide sheets, which provided a large surface area and the ability to trap electrons from the conduction band. As a result, the decreased recombination rate of electrons and holes enhanced the degradation ability of the composite based photocatalyst. A scavenging experiment was also performed to determine the most photoactive species taking part in the degradation process. In comparison among all prepared samples, AgNF@rGO showed the maximum photocatalytic activity. It was because of the large surface area of the AgNF@rGO. It was investigated that AgNF@rGO is the most effective catalyst for the degradation of coloured and colourless organic pollutants.     

Development of photocatalytic efficient Ti-based nanotubes and nanoribbons by conventional and microwave assisted synthesis strategies

Titanate nanotubes were prepared via a hydrothermal treatment of TiO₂ powders (Riedel De Haen) in a basic solution. Morphology and structure of the prepared samples were characterized by high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), XRD, FT-Raman spectroscopy, nitrogen sorption and DSC. The photocatalytic activity was evaluated by photocatalytic oxidation of rhodamine 6G. Trititanate nanotubes (TTNT) with inner pore diameters between 4 and 4.2 nm and surface areas up till 360 m²/g could be synthesized. The synthesis route was modified by introduction of a calcination step, by applying a lower hydrothermal temperature and microwave irradiation in order to increase the photocatalytic activity of the porous photoactive nanotubular materials. Calcination and a softer hydrothermal treatment led to the formation of anatase without affecting the surface area and nanotubular shape of the samples. In this way, the photocatalytic activity of the original trititanate nanotubes could be significantly increased. By making use of microwave assisted synthesis, the photocatalytic activity can also be increased due to the presence of anatase. However, by applying microwave synthesis, a different structure was obtained, nanoribbons (NR) instead of nanotubes, resulting in a decrease in surface area and porosity.     

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。