锐钛型纳米TiO_2光催化性能的研究

以TiCl4为原料,采用沸腾回流强迫水解法制备纳米TiO2,用XRD、TEM对粉体进行表征。采用甲基橙溶液进行光催化降解试验,研究了TiO2的煅烧温度、添加量以及溶液的初始pH值对光催化性能的影响。实验结果表明,当溶液pH=2,TiO2煅烧温度为600℃,添加量为0.8 g/L,光催化75 min甲基橙的脱色率为90.87%。     

掺Fe~(3+)的A-TiO_2的水热法制备及其可见光光催化性能

以硫酸钛为原料,用水热法制备了掺Fe3+的TiO2粉末,并对其晶相结构进行了分析,考察了自制掺Fe3+的TiO2对甲基蓝溶液的光催化性能。结果表明:所制备的TiO2为锐钛矿型TiO2(A-TiO2)。可见光照下,用自制掺Fe3+的A-TiO2降解甲基蓝溶液的最佳条件是:于ρ(甲基蓝)为8mg/L的溶液中加入0.0203g掺Fe3+为5%(摩尔分数)的A-TiO2粉末,并加入φ(H2O2)为4%,室温反应4h,最高降解率达到约88%。     

纳米BiVO_4的微波合成及其光催化性质

以五水硝酸铋和五氧化二钒为原料,通过微波合成法制备了纳米BiVO4,采用X-射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)表征了样品的形貌、结构和特性。XRD表明所制备的样品是纯的单斜晶型BiVO4;SEM显示样品的形貌呈层状结构;TEM进一步指出这些片层结构是由小粒子聚集而成的多孔结构。以催化降解甲基橙来考察其光催化性能。在100mL的10mg/L甲基橙溶液中加入0.12g经673K恒温热处理2h后的BiVO4及0.2mL H2O2,调节pH值为3.0,在可见光下照射90min后,降解率达到94.70%,催化性能良好。     

锐钛型掺铁TiO_2可见光催化降解苯胺的研究

为了研究掺铁TiO2对苯胺的光催化降解效果,以硫酸钛为原料采用水热法制备了锐钛型掺铁TiO2粉末,确定了它在可见光照射下对苯胺溶液的催化降解工艺条件。结果表明,在如下最佳条件下:苯胺初始质量浓度(0)为50 mg/L,溶液pH=7,掺铁0.2%(摩尔分数)的锐钛型TiO2的质量浓度为1.0 g/L,室温(17℃)下可见光照射反应1 h,苯胺的降解率达到71.46%。     

铁掺杂TiO_2纳米粉体的制备、表征及光催化性能研究

采用水热法制备了铁掺杂的TiO_2纳米粉体,通过X射线衍射(XRD)和傅立叶交换红外光谱(FT-IR)对样品进行表征。以甲基红模拟废水的降解率考察自制的铁掺杂TiO_2纳米粉体的光催化活性。XRD结果说明,产物为锐钛型TiO_2,在其三种晶型中光催化性能最好;FT-IR结果表明:所制的TiO_2结构中存在大量的—OH,预计它有较高的光催化活性;光催化性能实验结果显示:铁掺杂显著提高纳米TiO_2光催化活性,当Fe的掺杂量为摩尔分数1.4%时,其光催化活性最好,与纯TiO_2相比,光照2 h后甲基红的光催化降解率提高了33.66%;在最佳条件下(甲基红初始浓度为2 mg/L、p H值为6、掺Fe~(3+)量为摩尔分数1.4%、催化剂用量为0.8 g/L,可见光源为95 W白炽灯、光照为2 h),它对甲基红的降解率达到76.38%。     

电场辅助TiO2薄膜光催化降解甲基橙的影响

将电场引入到TiO2光催化降解甲基橙反应中,实验讨论了电场对TiO2光催化活性的影响及电场对薄膜最佳光催化活性层数的影响.结果表明:外加电场对光催化反应的影响明显,在外加电压30V时,TiO2光催化降解甲基橙的降解率提高了50%;此外,电场对催化剂TiO的最佳光催化活性层数有一定的影响,最佳光催化活性层数从无电场时的6层变为7层.     

铁、镧共掺杂纳米TiO2可见光催化性能研究

通过溶胶-凝胶(Sol-Gel)法制备了铁、镧共掺杂纳米TiO2,采用X线衍射仪(XRD)、X线光电子能谱(XPS)、紫外-可见分光光度计(UV-Vis)和荧光分光光度计(FL)等测试手段对样品进行表征。结果表明,500℃煅烧后的掺杂TiO2均呈锐钛矿型,平均粒径为6.1nm,掺杂抑制了TiO2粒径的长大,掺杂的Fe3+、La3+能有效进入TiO2晶格。掺杂使TiO2的吸收带边红移且在可见光区的光吸收增强,样品的荧光强度越小,催化效果越好。可见光光催化降解甲基橙实验结果表明,可见光照射5h,最佳共掺杂的0.01%Fe/0.6%La-TiO2对甲基橙的降解率达40.7%。     

大孔TiO_2-ZnO复合纳米材料的制备及其性能

采用溶胶-凝胶法和胶态晶体模板法,制备了大孔TiO2-ZnO复合纳米材料。其晶相结构和形貌特征采用X射线粉末衍射(XRD)、透视电子显微镜(TEM)进行了表征,并以甲基橙为降解对象,对其光催化活性进行了研究。结果表明,采用无皂乳液聚合法得到的聚苯乙烯(PS)微球粒径均匀,为900nm。以紧密堆积的PS胶态晶体为模板,制得的TiO2-ZnO复合纳米材料的大孔孔径约为900nm,孔壁厚度约为20nm。XRD结果显示,材料中的TiO2为锐钛矿型。光催化降解结果表明,大孔TiO2-ZnO复合纳米材料对甲基橙降解1.5h后降解率可达91.3%,与普通的TiO2-ZnO纳米粉体材料相比提高了11.2%.     

不同形貌TiO2微晶光催化降解甲基橙的研究

分别以钛酸正丁酯和四氯化钛为前驱体,以十二烷基苯磺酸钠(DBS)、十二烷基磺酸钠(SDS)、羟丙基甲基纤维素(HPMCS)为形状控制剂,利用溶胶-凝胶法制备不同形貌的TiO2微晶,并以甲基橙为模型化合物考察其光催化活性.XRD分析结果表明焙烧温度为500℃时所得TiO2均为锐钛型晶相.UV-vis分析表明加表面活性剂时所制备TiO2微晶吸收发生红移,带隙能下降.加SDS时所得立方形TiO2微晶的光催化活性高于其他样品.焙烧温度为600℃时TiO2微晶光催化活性最强,对甲基橙的降解速率最快.     

超声法制备TiO2纳米棒及其光催化性质的研究

研究了TiO2纳米棒的制备和形成机理及其在光催化降解活性艳红中的应用。采用超声法,以TiCl4为原料,制备了纳米TiO2。SEM结果显示所制备的TiO2为棒状结构,直径30 nm左右,长约200 nm。比表面积为60.500 7 m2/g。XRD显示其为金红石型晶体,700℃烧结后结晶程度增强,形貌保持不变,比表面积降到37.963 2 m2/g。超声法制备的TiO2纳米棒700℃烧结后应用于光催化降解活性艳红时,降解率高达98.94%,表现出优于P25的催化活性。     

Solvothermal synthesis of Bi2O3/BiVO4 heterojunction with enhanced visible-light photocatalytic performances

Novel, three-dimensional, flower-like Bi2O3/BiVO4 heterojunction photocatalysts have been prepared by the combination of homogeneous precipitation and two-step solvothermal method followed by thermal solution of NaOH etching process. The as-obtained samples were fully characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, Brunauer-Emmett-Teller surface area, and UV-vis diffusereflectance spectroscopy in detail. The crystallinity, microstructure, specific surface area, optical property and photocatalytic activity of samples greatly changed depending on solvothermal reaction time. The photocatalytic activities of samples were evaluated on the degradation of methyl orange (MO) under visible-light irradiation. The Bi2O3/BiVO4 exhibited much higher photocatalytic activities than pure BiVO4 and conventional TiO2 (P25). The result revealed that the three-dimensional heterojunction played a critical role in the separation of the electron and hole pairs and enhancement of the interfacial charge transfer efficiency, which was responsible for the enhanced photocatalytic activity.     

Preparation of erbium ion-doped TiO2 films and the study of their photocatalytic activity under simulated solar light

A series of erbium ion-doped TiO₂ (Er³⁺-TiO₂) films were prepared by a sol-gel dip/spin coating method, and the effect of the dosage of erbium ion (0-2.0 mol%), the films coating layers (1-5 layers), and calcination temperature (400-700℃) on the film structure and photocatalytic activity were investigated in detail. The films were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal analysis (TG-DTG) and UV-Vis diffusive reflectance spectra (DRS). The results showed that the films were composed of anatase, and no other TiO₂ phases (rutile and brookite). With the increase of the erbium ion dosage, the crystal size decreased. Erbium ion doping could enhance the thermal stability of TiO₂ and inhibit the increase of the crystallite size. Meanwhile doping of erbium ions gave rise to three typical absorption peaks within the range of visible light (400-700 nm), locating at 490, 523, and 654 nm, attributed to the transition of 4f electrons. The higher calcination temperature led to higher crystallinity and bigger crystal grains. The photocatalytic performance of the films was evaluated by degradation of methyl orange solution under simulated solar light. The highest quality film we prepared was with 4 layers, 1.0 mol% dosage of erbium ion, and the calcination temperature of 500℃. With this film, the degradation percentage of 7.8 mg/L methyl orange solution was up to 53.3% under simulated solar light after 6 h photoreaction.     

Ag/TiO2/WO3 nanoparticles with efficient visible light photocatalytic activity

A simple strategy for synthesizing Ag decorated TiO2/WO3 composite nanoparticles by sol-gel method used as recyclable photocatalyst is introduced. The photocatalytic efficiency to the degradation of methyl blue (MB) by Ag/TiO2/WO3 nanoparticles is studied under ultraviolet-visible (UV-Vis) light irradiation. It shows that the photocatalytic efficiency of Ag/TiO2/WO3 photocatalyst achieves 96% in 20 min, which is 16 times higher than that of pristine TiO2 at the same conditions. The Ag/TiO2/WO3 photocatalyst can still reach the degradation rate of 90% in the fifth degradation experiment, indicating a good stability and photocatalytic activity.     

N掺杂纳米TiO_2的制备及光催化性能研究

以盐酸羟胺为N源,按r(盐酸羟胺:钛酸四丁酯)分别为1:2,1:1,3:2,2:1和3:1掺杂,采用sol-gel法一步制备N掺杂纳米TiO2。研究了焙烧温度和N掺杂量对样品晶相结构及其在紫外光和紫外–可见光下对罗丹明B光催化活性的影响。结果表明,增大N掺杂量可抑制样品由锐钛矿相向金红石相转变。r(盐酸羟胺:钛酸四丁酯)为2:1时,样品经500℃焙烧后对罗丹明B的紫外光催化降解率1h内达54.81%,样品经600℃焙烧后对罗丹明B的紫外–可见光催化降解率2h内可达99.13%。     

锐钛矿TiO_2的水热法制备以及紫外光降解甲醛

用硫酸钛水热法制备了纳米TiO2光催化剂,研究了纳米TiO2的形态结构特征及其光催化性能,并探讨了甲醛溶液的初始pH值和初始浓度、TiO2用量、降解温度和时间对光催化降解反应的影响。结果表明,制备的锐钛矿TiO2产物平整而密实,它由八面体结构的TiO2纳米晶大面积自组装而成。在35℃降解温度下采用254nm紫外光源照射1h后,锐钛矿TiO2对甲醛的降解率达到51.10%,2h后达68.42%。