Preparation and gaseous photocatalytic activity of smooth potassium dititanate film

A new smooth potassium dititanate film was prepared by sol-gel method and characterized by thermogravimetry (TG) and differential scanning calorimetry (DSC), X-ray diffraction (XRD), atomic force microscopy (AFM), UV-Visible diffuse reflectance and Raman spectroscopy. The gaseous photocatalytic activity of smooth K₂Ti₂O₅ films was studied using contact angle analysis from the photocatalytic decomposition of octadecyltrichlorosilane (OTS) based self-assembled monolayers (SAMs) formed on K₂Ti₂O₅ films. The photocurrent response of the film was determined by an electrochemical method. It was shown that the films were smooth, compact, and transparent when formed on glass. Compared with TiO₂ film, the K₂Ti₂O₅ film showed wide absorption in the ultraviolet and visible region. It was found that the monolayers on K₂Ti₂O₅ decomposed much faster than those on TiO₂ under UV irradiation of 254 nm in air. The film also exhibited a stronger photoresponse and a more stable anodic photocurrent. The K₂Ti₂O₅ film efficiently decomposes the alkylsiloxane monolayers under UVirradiation in air and it was found to be a good photocatalyst for gaseous organic pollutant treatment. __________ Translated from Journal of functional materials, 2007, 38(7): 1067–1070, 1073 [译自: 功能材料]     

光催化剂膜的制备及活性评价

采用溶胶-凝胶法在玻璃纤维布上成功制备了锐钛矿型TiO2薄膜。并以腐殖酸为处理对象,对TiO2膜的光催化氧化活性进行评价。结果表明,该固定TiO2膜光催化体系对降解腐殖酸有良好的效果,反应3 h,腐殖酸的降解率达52.9%。显示了光催化氧化法在水处理中的良好应用前景。     

TiO2光催化膜的制备及其性能研究

采用溶胶-凝胶法制备了Ti O₂粉体,并以聚乙烯醇和聚多巴胺为载体,采用浇铸法制备出Ti O₂光催化薄膜。对膜的耐水性和光催化降解性能进行了测试。结果表明,光照30min甲基橙的降解率为89.33%,光照60min甲基橙的降解率为93%。随着薄膜内Ti O₂添加量的增加,膜的光催化性能逐渐增强,在水中的吸水率逐渐降低。     

ZnO薄膜的制备及光催化性能研究

采用溶胶 凝胶法在石英玻璃基底上制备出性能优良的ZnO薄膜。并通过XRD、AFM和UV VIS吸收光谱对薄膜的结构及形貌进行表征,研究了降解温度、苯酚溶液的初始浓度和空气流量对ZnO薄膜光催化性能的影响,ZnO薄膜光催化降解苯酚的最佳条件：降解温度25～45 ℃,空气流量40 mL·min^－1。起始浓度越低,降解效果越显著,同时实现了ZnO薄膜催化剂的固载,催化效果显著。同时研究了ZnO薄膜催化剂的固载。固载后的ZnO薄膜催化剂催化效果显著,且便于回收利用。     

Fe~(3+)改性TiO_2薄膜的制备、表征及光催化性能研究

采用溶胶-凝胶法,制备了纳米Fe3+/TiO2薄膜,利用XRD、TEM等测试手段进行了样品的表征分析,以降解含阿奇霉素废水为反应模型,研究了纳米Fe3+/TiO2薄膜的紫外光照射催化活性及薄膜的重复使用效果。结果表明,纳米Fe3+/TiO2薄膜不易失活,其催化活性寿命较粉体纳米Fe3+/TiO2的强,且再生性能好,薄膜重复使用4次,仍有明显的降解效果。     

Preparation and photocatalytic activity of Keggin-ion tungstate and TiO2 hybrid layer-by-layer film composites

Keggin ions (PW₁₂O₄₀³⁻ (PW₁₂), SiW₁₂O₄₀⁴⁻ (SiW₁₂), H₂W₁₂O₄₀⁶⁻ (H₂W₁₂)) and TiO₂ hybrid thin films were prepared using the layer-by-layer method. Their photocatalytic activities were investigated using gaseous 2-propanol decomposition. All films were transparent in the visible wavelength range. For 2-propanol decomposition, H₂W₁₂ was the most effective for the combination with TiO₂ despite having the smallest TiO₂ deposition amount. The photocatalytic activity of the PW₁₂–TiO₂ hybrid film was increased 2.3 times by visible light with UV illumination. This increase was less remarkable for hybrid films of other Keggin ions, suggesting that the visible light excitation of reduced PW₁₂ plays an important role in the enhancement of 2-propanol decomposition.     

La掺杂铌酸钾的水热合成及其光催化性能研究

以氢氧化钾、氧化铌和硝酸镧为原料,采用水热法合成了结晶度高、掺杂不同含量的稀土La的K4Nb6O17纳米片状材料。借助XRD、SEM-EDX和Raman等技术手段对催化剂进行了表征。研究结果表明,La的掺杂并未改变催化剂材料的晶体结构,La/Nb摩尔比为0.5%的铌酸钾具有最佳的光催化活性,对以有机染料罗丹明为目标降解物的反应具有高效的光催化降解性能。在36 W紫外灯作用下,30 mg催化剂可以在80 min内实现对100 mL的罗丹明溶液(20 mg/L)的快速降解。     

N掺杂纳米TiO2的制备及其光催化性能

以钛酸四丁酯和乙醇为原料,尿素为氮源,室温下采用溶胶-凝胶法制备了氮掺杂的纳米TiO2粉末。采用XRD、TEM、UV-Vis DRS对样品进行了表征。结果表明：N掺杂使纳米TiO2的光谱响应范围拓展到可见光区。较佳制备条件是：n(钛酸四丁酯)∶n(尿素)为1∶3,400 ℃下煅烧3.5 h,所得样品为锐钛矿晶型,平均粒径为13 nm。光降解甲基橙实验中,溶液pH值为4.0时,降解率最大,反应3 h降解率可达70.5%。     

纳米TiO2陶瓷珠膜的制备及其光催化性能研究

以钛酸四丁酯为前驱体，采用溶胶-凝胶法，在低温或常温下通过溶液中发生水解、聚合等化学反应，生成溶胶，进而生成具有一定空间结构的凝胶，经过干燥、减压和热处理，制备出纳米TiO₂并在陶瓷珠载体上附着。研究了陶瓷珠负载TiO2对阳离子蓝的光催化降解性能。     

纳米线和纳米碗的合成及其光催化性能

采用简单的水热法合成ZnO纳米线和纳米碗,应用XRD和SEM对其结构和形貌进行表征,并以罗丹明B为模型污染物比较两种样品的光催化活性.结果表明,具有特定形貌的小尺寸纳米线具有较高的催化活性.     

Preparation of TiO2 ultrafine nanopowder with large surface area and its photocatalytic activity for gaseous nitrogen oxides

TiO₂ nanopowder with a large surface area and high crystallinity was synthesized by a thermal decomposition process. The physicochemical properties of the prepared powders were examined by X-ray diffraction, transmission electron microscopy and nitrogen adsorption-desorption isotherms. The nanocrystallites of the prepared powers were considerably smaller than those of the commercial photocatalyst (Degussa, P25), and the particles had a dense polyhedral structure. In addition, the particles had a mainly disordered mesoporous structure with a pore volume that varied according to the pore size in the range of 2-20 nm. The photocatalytic activity of the prepared photocatalyst was obviously higher than that of P25 on the photodegradation of gaseous nitrogen oxides under UV_{254 + 185 nm} lamp irradiation. Above 40% relative humidity, the NO_x removal efficiency of the prepared photocatalyst was 10% higher than that of P25. Furthermore, a suitable relative humidity and longer residence time were found to enhance the photocatalytic oxidation of gaseous nitrogen oxides by UV_{254 + 185 nm} lamp irradiation and TiO₂ nanoparticles.     

氨基修饰片状氮化碳的制备及光催化性能

石墨相氮化碳是一种低成本易获得的可见光响应光催化剂,但由于比表面积小、光生载流子易复合等缺点限制了其应用。为克服传统氮化碳的缺陷,本实验以尿素和三聚氰胺为原料,通过水热预处理改性前体,再用高温煅烧法成功制备出氨基修饰片状氮化碳光催化材料。并通过X射线衍射（XRD）、扫描电子显微镜（SEM）和X射线光电子能谱仪（XPS）等手段对样品的晶格结构和形貌特征等进行表征。结果表明,成功引入氨基基团的片状氮化碳,比表面积增加且光生载流子复合率显著降低。以罗丹明B和壬基酚溶液的光降解考察材料光催化性能,发现氨基修饰片状氮化碳对其去除率分别为80.69%和50.7%,分别是传统块状氮化碳的2.45倍和2.19倍,是未修饰片状氮化碳的1.26倍和1.21倍。且氨基修饰片状氮化碳材料重复使用5次后仍具有较高光催化活性,光催化性能显著提高。     

金属酞菁光复合催化剂的制备及光催化性能研究

采用固相熔融法制备了不同中心金属的酞菁配合物MPc(M=Mn2+、Co2+、Ni2+)光复合催化剂,研究MPc对亚甲基蓝的催化降解效果。结果表明,可见光照射下,MPc对亚甲基蓝的降解效率Ni Pc> MnPc> Co Pc,最佳反应条件为:空气通入量120 m L/min,催化剂Ni Pc的加入量1. 0 g/L,反应150 min时,10 mg/L亚甲基蓝的降解率达97. 5%。降解反应符合一级动力学议程。     

纳米SiO_2的表面改性

分别用吐温-80、油酸、十二烷基苯磺酸钠、硅烷偶联3-氨丙基三乙氧基硅烷(KH550)和硅烷偶联剂γ-(甲基丙烯酰氧)丙基三甲氧基硅烷(KH570)处理纳米二氧化硅,用沉降体积和亲油化度来对比改性效果,结果表明KH570改性效果最好,其最佳工艺条件为:KH570用量为8%,反应温度为70℃,反应时间为2 h,反应pH为5.5。对KH570改性前后的纳米粉体进行了红外光谱分析、热重分析、紫外-可见光谱分析、扫描电镜分析等表征。结果表明,硅烷偶联剂与纳米二氧化硅之间形成了化学结合,改性后的纳米SiO_2分散性提高,从而更好地应用于聚合物材料中。     

球形BiVO4光催化剂的制备及光催化性能

以Bi(NO_3)_2·5H_2O和NH_4VO_3为原料,采用微乳液法制备球型BiVO_4光催化剂。用亚甲基蓝溶液模拟有机废水,在紫外光照下,研究亚甲基蓝的光催化降解过程。利用X射线衍射和扫描电子显微镜等测试技术,对球型BiVO_4光催化剂进行表征。结果表明,乳液法制备的球型BiVO_4光催化剂具有良好的光催化性能,对亚甲基蓝的光降解率几乎可达100%。     

氧化钨空心球制备及其光催化性能

在较低温度下制备出氧化钨空心球,一方面可以提高催化剂对光源的利用率,另一方面能够降低催化剂成本。以氯化钨为钨源,将其在70 ℃下醇解和水解,于磺化聚苯乙烯微球表面形成氧化钨前驱体纳米颗粒,通过煅烧制备了氧化钨空心球。利用场发射扫描电镜（FE-SEM）、X射线衍射（XRD）、傅里叶变换红外光谱（FT-IR）和综合热分析（TG-DTG）对所制备的产物进行表征。通过光催化降解罗丹明B溶液来测试氧化钨空心球的催化性能,结果表明光照60 min后催化剂对罗丹明B溶液的光催化降解率可达86.61%。     

钴掺杂二氧化钛光催化剂制备及光催化活性

采用溶胶-凝胶法制备了纯二氧化钛和不同钴掺杂量的二氧化钛复合纳米粒子。并用XRD、UV-Vis对样品组织结构进行了表征。以甲基橙（OM）的光催化降解为探针反应,评价了可见光催化活性,研究了不同热处理温度、不同钴掺杂量对二氧化钛光催化性能的影响。确定了最佳钴掺杂量和热处理温度分别为1%（物质的量分数）和600  ℃。在此条件下,钴的掺杂对二氧化钛的相变有很大的抑制作用,并使其光谱响应范围向可见光区拓展。与未掺杂的二氧化钛相比较,经钴掺杂的二氧化钛具有更高的催化性能。     

Evaluating the photocatalytic activity of Pt/TNT film catalyst

TiO₂ nanotubes (TNT) were prepared by a hydrothermal method from the commercially available TiO₂-P25. Five types of TNT were produced at different temperatures (120 °C, 130 °C, and 150 °C) and by using different reaction times (12 h, 24 h, and 30 h). The photocatalytic reactor that was used is a film catalytic reactor, in which the height of the catalyst is 1.0 mm. The BET and FESEM analysis results showed that TNT130-24 (130 °C, 24 h) and TNT150-12 (150 °C, 12 h) possessed well-formed tubular structures with a high specific surface area (282.9–316.7 m² g⁻¹) and large pore volumes (0.62–0.70 cm³ g⁻¹). However, TNT120-30 (120 °C, 30 h) presented the best photocatalytic activity upon CO removal due to the synergistic effect of TiO₂ nanotubes and TiO₂ particles. After the TNT catalysts were modified with Pt particles, the removal efficiency was in the order of Pt/TNT120-30>Pt/TNT130-24>Pt/P25. Pt/TNT120-30 showed 99% removal efficiency in a continuous photoreactor with a high space velocity of 1.79×10⁴ h⁻¹. The results of the TEM and DRS analyses confirmed that the Pt particles enhanced the photocatalytic reaction, which was attributed to the well-dispersed nature of the 1 nm nanoscaled Pt particles on the surfaces of the TNT catalysts, and narrowed the band gap from 3.22 eV to 3.01 eV.     

氮铈共掺杂纳米TiO2的制备和光催化活性研究

采用水解沉淀法分别制备了未掺杂、氮掺杂和不同Ce^4＋浓度的氮、铈共掺杂纳米二氧化钛粉体,并利用XRD、TEM、XPS、UV-vis对其进行表征,以甲基橙的光催化降解为模型反应,考察其在太阳光下的光催化活性。结果表明,450℃下煅烧3h制备的纳米TiO2粉体均为锐态矿型,铈的掺入使衍射峰宽化;氮、铈共掺杂能抑制锐钛矿晶粒的生长,减少团聚,使晶粒细化。N取代了TiO2晶格中的部分氧原子形成N2p掺杂能级,而铈以Ce^4＋、Ce^4＋两种价态存在于TiO2中。氮、铈的协同作用不仅使TiO2的光吸收带边红移,也能明显提高TiO2在紫外光区的吸收强度。光催化降解甲基橙实验结果表明：当掺杂量为0．6％时,Ce-N-TiO2的光催化效率最高,约为纯二氧化钛的2倍。