固相反应法制备纳米氧化铜及其光催化性能研究

以硫酸铜为原料,采用固相反应法制备纳米级氧化铜,讨论了反应物配比、分散时间及表面活性剂对产物粒径大小的影响,在太阳光照射下,研究纳米CuO对有机染料的降解.结果表明,最佳反应条件为:n(CuSO4):n(NaOH)为1:3.5,超声波分散时间为8 min,表面活性剂聚二乙醇600的用量为0.5％.产物为纤维状纳米CuO...     

固相反应法制备纳米氧化铜及其光催化性能研究

以硫酸铜为原料,采用固相反应法制备纳米级氧化铜,讨论了反应物配比、分散时间及表面活性剂对产物粒径大小的影响,在太阳光照射下,研究纳米CuO对有机染料的降解。结果表明,最佳反应条件为:n(CuSO_4)∶n(NaOH)为1∶3.5,超声波分散时间为8 min,表面活性剂聚二乙醇600的用量为0.5%。产物为纤维状纳米CuO,具有较好的光催化活性,对50 mL浓度10 mg/L有机染料甲基紫,加入0.025 g纳米CuO,在太阳光照射下5 h,甲基紫降解率70%。     

沉淀转化法制备纳米氧化铜及其光催化性能研究

以CuSO_4为原料,采用沉淀转化法制备纳米级氧化铜,讨论了反应条件对产物粒径大小的影响,得出最佳的反应工艺条件;利用X射线衍射(XRD)和透射电镜(TEM)对产物的组成及大小进行表征;以制备的纳米CuO产品作为光催化剂,在太阳光照射下研究其对有机染料的降解实验。结果表明,沉淀转化法的最佳反应条件为:反应温度为80℃,反应终点的pH值为13,CuSO_4溶液的浓度为0.1 mol/L,NaOH水溶液的浓度为2 mol/L;制备的纳米CuO有较好的光催化活性,对有机染料甲基紫的降解率约为70%。     

氧化铜纳米粉体的制备工艺研究

以三水硝酸铜为反应物,氨水为络合剂,氢氧化钠为沉淀剂,乙醇水混合溶液为反应溶剂,聚乙二醇为分散剂,采用络合沉淀法,成功制备出平均粒径约20nm的氧化铜单晶纳米粉体。通过单因素实验和正交实验考察了硝酸铜溶液初始浓度、反应温度及氢氧化钠与硝酸铜物质的量比等因素对产物粒径大小的影响,利用x射线衍射（XRD）、透射电镜（TEM）和红外光谱仪（FT-IR）等对产物进行表征分析。研究结果表明,影响其粒径大小主要因素的主次顺序依次是：反应温度,硝酸铜溶液初始浓度及氢氧化钠与硝酸铜的物质的量比;优化制备工艺条件为：反应温度70℃,硝酸铜溶液初始浓度0．3mol／L,氢氧化钠与硝酸铜的物质的量比3：1,氨与硝酸铜的物质的量比5：1;氧化铜纳米粉体的红外吸收峰出现了红移和蓝移同时并存的反常现象。     

二氧化钛的沉积-沉淀水热制备及其光催化性能

以硫酸钛为原料,采用沉积-沉淀水热法制得了TiO2粉体光催化剂。以光催化降解活性艳红X-3B作为模型反应,考察了所制得的TiO2粉体的光催化性能。发现140℃沉积-沉淀水热反应20 h、600℃焙烧制得的TiO2粉体光催化活性明显高于Degussa P25 TiO2,并且该TiO2粉体光催化剂沉降性好,易分离。     

棒状纳米ZnO的制备及其光催化性能研究

采用溶胶-凝胶法,以醋酸锌、草酸为主要原料,乙二胺为添加剂制得棒状结构的纳米ZnO,通过XRD和TEM对产物的结构和形貌进行了表征,并以有机染料亚甲基蓝溶液为光催化反应模型降解物,考察了样品的光催化活性。结果表明,ZnO纳米棒为纤锌矿结构的六方相ZnO,对亚甲基蓝溶液具有良好的光催化活性,且乙二胺的添加量对产物的形貌和光催化活性具有显著影响。     

沉淀转化法制备不同粒径的纳米氧化镁

以氧化镁和碳酸铵为原料,采用沉淀转化法研究了不同粒径纳米氧化镁的制备,讨论了加料方式、反应物配比、反应温度、煅烧温度等条件对其粒径的影响。实验结果表明:用沉淀转化法制备出不同粒径的纳米氧化镁颗粒;加料方式对纳米氧化镁的平均粒径有影响,滴加加料法比一次加料法制备的氧化镁粒径大;反应条件对粒径也有显著影响,反应物配比越大,纳米氧化镁粒径越大;反应温度越高,其粒径越小;煅烧温度越高,其粒径越大。     

共沉淀法制备Bi12TiO20纳米粉体及其光催化性能研究

以五水硝酸铋（Bi（NO3）3.5H2O）和钛酸四丁酯（C4H9O）4Ti）为反应物,利用共沉淀法制备Bi12TiO20前驱体,通过一定的热处理获得Bi12TiO20纳米粉体。采用XRD和TEM对其结构和形貌进行了表征,以紫外及可见光为光源、甲基橙为目标降解物,评价了Bi12TiO20粉体的光催化性能。结果表明：在热处理温度为550℃时合成的Bi12TiO20粉体,紫外-可见漫反射光谱测试显示吸收带发生了红移,当光照时间为4h时,其在紫外光和可见光下对甲基橙的降解率分别为93%和54%。     

氮掺杂纳米二氧化钛的制备及其光催化性能

以三乙醇胺为氮源采用水热法制备了氮掺杂纳米TiO2光催化剂,采用XRD、TEM和UV—vis／DRS分析、表征氮掺杂对TiO2微晶尺寸、晶体结构、表面组成与光学性能的影响,并通过降解甲基橙溶液研究其光催化活性。结果表明：制得的氮掺杂二氧化钛均为锐钛矿型,粒径约为10nm,a掺杂引起光催化剂的吸收波长向可见光区红移。当pH=11．0,300℃焙烧3h时制得的氮掺杂TiO2光催化活性最强,甲基橙50min的降解率达98％。     

沉淀转化法制备NiO催化剂及其催化性能研究

采用沉淀转化法制备NiO催化剂,研究了沉淀条件、焙烧温度、焙烧时间等对催化剂活性的影响。结果表明,以醇-水溶液为溶剂,沉淀温度60℃,600℃下焙烧6 h所制得的NiO催化剂,对低浓度甲酸溶液的催化分解率为71%;中频率(45 kHz)、中功率(150 W)超声场的协同作用可使NiO对低浓度甲酸溶液的催化分解率提高至75%。XRD和TEM表征结果显示,超声作用使NiO催化剂的平均晶粒从32 nm减小至20 nm,所制备的NiO纯度高,且结构为标准立方相晶体。     

纳米Cu2O的特殊液相沉淀法制备及其光催化活性

采用高强度机械混合的特殊液相沉淀法制备了纳米Cu2O粉体,通过TEM和XRD对其进行表征。用它做催化剂在日光作用下对酸性品红溶液进行了光催化降解实验,研究了葡萄糖添加浓度、酸性品红溶液的初始浓度和催化剂的重复使用对光催化性能的影响。结果表明分散剂葡萄糖浓度为7g/L时制得的纳米Cu2O光催化活性最佳,当酸性品红溶液的初始浓度为6 mg/L时,2.5 h降解率高达99.1%,重复使用6次后其降解率仍可达到75%。     

Enhanced photoluminescence and photocatalytic activity of ZnO-ZnWO4 nanocomposites synthesized by a precipitation method

Zinc oxide (ZnO)-zinc tungstate (ZnWO₄) nanocomposites ((ZnO)_1−x(ZnWO₄)_x, x=0, 0.1, 0.2, 0.3, 0.5, 0.7, 0.9, 1) were prepared using a convenient precipitation method. The structural, morphological and optical properties of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), Ultraviolet-visible (UV–vis) absorbance measurements and photoluminescence (PL) spectroscopy. The photocatalytic performance of the samples was evaluated utilizing methyl orange (MO) under UV light irradiation. The SEM and HR-TEM analyses revealed that an intimate contact was possibly formed at the ZnO-ZnWO₄ interface. The PL spectra of the composites of ZnO and ZnWO₄ exhibited a stronger blue-green emission band in the range of 400–540 nm under 272 nm radiations compared with that of single phase ZnWO₄. And their photocatalytic performances were also elevated significantly when the value of the x was 0.1, 0.2, 0.3 and 0.5, almost twice as much to that of ZnO. The superior fluorescent and photocatalytic performances might be ascribed to the suitable energy levels related to the intimate contact between two different semiconductors, which are beneficial to the interfacial charge transfer between the conduction and valence bands.     

不同体系光催化制备纳米Ag/TiO_2光催化剂活性比较

以控制中和水解法制备的锐钛矿型纳米TiO2为原料.在不同体系中,通过控制反应初始n(Ag):n(Ti),用直接光催化反应的方法制备了蚋米Ag/TiO2复合先催化剂,并且对产品进行了表征和分析.结果表明,Ag的改性能显著提高光催化效率,乙醇有机溶剂体系和水体系中制得的Ag/TiO2复合光催化剂的光催化活性相差不大,最佳n(Ag),n(Ti)为0.1%.同时与UV光相比在室内自然先作用下得到的Ag/TiO2复合光催化剂表现出更好的活性,40 min甲基橙先催化降解率比蚋米TiO2高约44%.     

Optical and photocatalytic properties of La-doped ZnO nanoparticles prepared via precipitation and mechanical milling method

The synthetic method used for preparing ZnO nanoparticles strongly influenced the products obtained. The ZnO powders incorporated more La when prepared by the mechanical milling method whereas the La₂O₃/ZnO composite nanoparticles were formed better using the precipitation method. The phase formations were detected by the X-ray diffraction technique and the morphology of the samples was followed by scanning electron microscopy. The La contents affected the crystallite size. This was explained by the formation of LaOZn on the surface of the samples and by the Zener pinning effect. The band gap energy of the samples was influenced by repulsion between the valence and conduction bands and the presence of a secondary phase. The photocatalytic degradation of a methylene blue solution by the samples depended upon the number of oxygen vacancies.     

微乳液法制备纳米SiO2/TiO2及其光催化性能

以无机物聚合硅酸为硅源、硫酸钛为钛源,采用微乳液法制备了SiO2/TiO2复合光催化剂,考察了制备条件对SiO2/TiO2光催化活性的影响,并利用SEM、FTIR、XRD和BET等技术手段对光催化剂进行了表征。结果证明,SiO2和TiO2颗粒之间存在着强的相互作用,形成了Ti-O-Si键,从而抑制了TiO2粒径的增大,延缓了TiO2由锐钛矿相向金红石相的转变。对甲基橙等染料的光催化降解实验结果表明,SiO2/TiO2的光催化活性并非随着TiO2的含量增加而提高,当硅与钛物质的量比为1∶1并在160℃的温度下水热合成2.5 h时,SiO2/TiO2光催化剂在紫外光照15 min后对甲基橙的脱色率为85.5%,与同等条件下制备的TiO2相比具有更好的光催化活性和更大的比表面积。     

Effect of calcination temperature on the photocatalytic activity of CaSb2O6 nanoparticles prepared by co-precipitation method

CaSb₂O₆ precursors were obtained via co-precipitation technique and subsequently they underwent calcination at different temperatures. The effect of calcination temperature on the crystallite size, specific surface area, crystallinity and defect structure of CaSb₂O₆ has been studied in detail. It is found that the photocatalytic activity of the as-prepared CaSb₂O₆ samples for methyl orange (MO) degradation under UV light is strongly dependent on the calcination temperature. The results demonstrated that the CaSb₂O₆ nanoparticles calcined at 900 °C possess the best photocatalytic activity and excellent photocatalytic stability. A possible mechanism of the photocatalysis over CaSb₂O₆ was also presented.     

反溶剂沉淀法合成Fe3+掺杂ZnO纳米结构及其可见光催化性能

以氯化胆碱-草酸低共熔溶剂(ChCl-OA DES)为溶剂，ZnO和Fe₂O₃为原料，通过简单的反溶剂沉淀法制备出不同掺杂浓度的Fe³⁺掺杂ZnO(Fe-ZnO)纳米结构。采用SEM、XRD、拉曼光谱、XPS等手段对所制Fe-ZnO结构与形貌进行了表征。结果表明，Fe-ZnO是由直径为20～30 nm纳米晶组装而成的微米棒。不同掺杂浓度的Fe-ZnO纳米晶均为六方铅锌矿结构，Fe³⁺很好地进入ZnO晶格。同时考察了所制Fe-ZnO的光吸收特性和光催化活性，发现Fe³⁺掺杂使其吸收峰红移至可见光范围，有效增强了可见光区域的催化活性。当Fe掺杂量为1.0%(atom)时，样品的光催化活性最好，比ZnO增大了约102倍。这说明Fe³⁺掺杂可改善ZnO对可见光光子的捕获能力。     

水热法制备的Ce-ZnO结构表征及其光催化性能研究

采用水热法制备不同摩尔比的稀土元素Ce掺杂Zn O光催化纳米材料Ce-Zn O,用红外(FTIR)光谱、X射线衍射(XRD)、紫外-可见光谱(UV-Vis)、光致发光(PL)等对其进行表征;研究了不同Ce掺杂量的Ce-Zn O对亚甲基蓝溶液(MB)光催化性能的影响。结果表明,Ce掺杂量2%时,Zn O的表面状态得到明显改善,生成更多的羟基自由基;同时增加光生电子空穴对的浓度,显著提高Zn O的光催化性能;经过2 h紫外汞灯照射,其降解率达到93.68%;且经过5次循环使用后,2%Ce-Zn O的降解率依旧能达到85%以上,具有良好的光催化性能和循环稳定性。     

Photocatalytic water splitting over ZrO2 prepared by precipitation method

ZrO₂ prepared by the precipitation method of zirconium oxychloride with various hydrolyzing agents was studied for photocatalytic water splitting reaction under UV light irradiation. The crystal structure as well surface properties were varied with the hydrolyzing agent of KOH, NH₄OH, and NH₂CONH₂. Especially, the surface area of the prepared ZrO₂ calcined at the same temperature of 750 °C for 6 h was dependent highly on the hydrolyzing agent, and thus the highest photocatalytic activity was obtained for ZrO₂ with the highest surface area when KOH was used as a hydrolyzing agent, In the presence of Na₂CO₃, the photocatalytic activity of ZrO₂ increased by 2–3 fold, which was ascribed to the physically adsorbed carbonate species on the ZrO₂ surface. This paper is dedicated to Professor Hyun-Ku Rhee on the occasion of his retirement from Seoul National University.