Preparation and performances of mesoporous TiO2 film photocatalyst supported on stainless steel

Mesoporous TiO₂ film photocatalysts supported on stainless steel substrates were prepared using the sol–gel method with Ti(OC₄H₉)₄ as a precursor and poly ethylene glycol (PEG) as a structure-directing agent. Mesoporous TiO₂ film with a pore diameter of about 15 nm was obtained with the addition of PEG (molecular WEIGHT =400). The pore diameter of TiO₂film was varied with molecular weight of PEG additive. The structure-directing process was also discussed. Mesoscopically ordered inorganic/polymer composites were believed to form during the process. Compared to conventional TiO₂ film photocatalyst, the mesoporous TiO₂ film showed a good performance for the photo degradation of rhodamine B (RB) solution irradiated with UV light of 365 nm. The photo degradation constant of rhodamine B for mesoporous TiO₂ film photocatalyst can arrive at 22 times of that for conventional TiO₂ film photocatalyst. Also an excellent performance for the degradation of gaseous formaldehyde with mesoporous film photocatalyst was obtained. The photo degradation rate of gaseous formaldehyde for mesoporous TiO₂ film photocatalyst can arrive at six times of that for conventional TiO₂ film photocatalyst.     

Preparation and characterization of a novel activated carbon‐supported N‐doped visible light response photocatalyst (TiO2−xNy/AC)

A photocatalyst, TiO_2?xN_y/AC (activated carbon (AC) supported N‐doped TiO₂), highly active in both the Vis and UV range, was prepared by calcination of the TiO₂ precursor prepared by acid‐catalyzed hydrolysis in an ammonia atmosphere. The powders were characterized by diffuse reflectance spectroscopy, scanning electron microscopy, X‐ray diffraction, N₂ adsorption, Fourier transform infrared spectroscopy and phenol degradation. The doped N in the TiO₂ crystal lattice creates an electron‐occupied intra‐band gap allowing electron‐hole pair generation under Vis irradiation (500–560 nm). The TiO_2?xN_y/AC exhibited high levels of activity and the same activity trends for phenol degradation under both Vis and UV irradiation: TiO_2?xN_y/AC calcined at 500 °C for 4 h exhibited the highest activity. The band‐gap level newly formed by doped N can act as a center for the photo‐generated holes and is beneficial for the UV activity enhancement. The performance of the prepared TiO_2?xN_y/AC photocatalyst revealed its practical potential in the field of solar photocatalytic degradation of aqueous contaminants. Copyright © 2007 Society of Chemical Industry     

Ag nanoparticles loaded TiO2/MWCNT ternary nanocomposite: A visible-light-driven photocatalyst with enhanced photocatalytic performance and stability

A visible light active photocatalyst, Ag/TiO₂/MWCNT was synthesized by loading of Ag nanoparticles onto TiO₂/MWCNT nanocomposite. The photocatalytic activity of Ag/TiO₂/MWCNT ternary nanocomposite was evaluated for the degradation of methylene blue dye under UV and visible light irradiation. Ag/TiO₂/MWCNT ternary nanocomposite exhibits (~9 times) higher photocatalytic activity than TiO₂/MWCNT and (~2 times) higher than Ag/TiO₂ binary nanocomposites under visible light irradiation. The enhancement in the photocatalytic activity is attributed to the synergistic effect between Ag nanoparticles and MWCNT, which enhance the charge separation efficiency by Schottky barrier formation at Ag/TiO₂ interface and role of MWCNT as an electron reservoir. Effect of different scavengers on the degradation of methylene blue dye in the presence of catalyst has been investigated to find the role of photogenerated electrons and holes. Simultaneously, the Ag/TiO₂/MWCNT shows excellent photocatalytic stability. This work highlights the importance of Ag/TiO₂/MWCNT ternary nanocomposite as highly efficient and stable visible-light-driven photocatalyst for the degradation of organic dyes.     

纳米光催化剂TiO_2/Fe_3O_4的制备及表征

采用两步法制备磁性负载纳米光催化剂TiO2/Fe3O4。首先用液相共沉淀法制备磁性纳米Fe3O4颗粒;然后用溶胶-凝胶法,以钛酸四正丁酯为先驱体,通过水解缩聚在Fe3O4纳米颗粒表面包覆TiO2层,得到易于磁分离回收的复合纳米光催化剂TiO2/Fe3O4,粒径大约为30 nm。利用TEM、XRD、FT-IR、VSM对Fe3O4和TiO2/Fe3O4的结构和性能进行了表征,结果表明,制备的Fe3O4为面心立方晶体(FCC)结构,具有超顺磁性;TiO2为锐钛矿相,包覆在Fe3O4的表面,形成了核-壳式结构的TiO2/Fe3O4复合光催化剂。     

以稻壳-TiO_2为原料化学活化制备TiO_2/SiO_2/AC光催化剂

以钛酸四丁酯[Ti(OBu)4]为钛源,采用溶胶-凝胶法将TiO2前驱体负载于稻壳表面,进一步以该复合物为原料,经炭化和KOH化学活化制得具有可见光激发活性的活性炭负载TiO2/SiO2光催化剂。以对亚甲基蓝的脱色率为依据探讨了钛酸四丁酯的用量及煅烧温度对催化剂光催化性能的影响。利用傅立叶变换红外光谱、扫描电镜及X射线衍射等测试手段对光催化剂的结构、表面形态及晶相结构进行了表征。结果表明,TiO2晶型为锐钛矿相结构,并且与SiO2作用形成了Ti—O—Si键。     

TiO2薄膜和多孔薄膜的溶胶-凝胶法制备与表征

本文以钛酸丁酯[Ti（OC4H9）4]、去离子水、盐酸和聚乙二醇（PEG）1000为原料,采用溶胶-凝胶法和旋转涂膜工艺,在玻璃基底上制备纳米TiO2薄膜和TiO2多孔薄膜.利用原子力显微镜（AFM）、X射线衍射仪（XRD）和紫外-可见光谱仪（UV-Vis）对薄膜进行分析表征.结果表明,实验制备的TiO2粉体为锐钛矿晶型,纳米TiO2薄膜的平均粗糙度为17.2nm,TiO2多孔薄膜平均粗糙度为1.55 nm.TiO2多孔薄膜有较高的透射性和光催化活性,可直接用于光催化降解有机物等领域.     

新型三元复合可见光催化剂Au/Bi_2WO_6/RGO的制备及其性能

采用溶剂热法制备钨酸铋/石墨烯(Bi_2WO_6/RGO)光催化剂,然后利用光还原法将Au纳米颗粒沉积于该二元光催化剂表面,制备出Au/Bi_2WO_6/RGO三元复合可见光催化剂。运用X射线衍射(XRD)、紫外可见漫反射吸收光谱(UV-Vis DRS)和透射电镜(TEM)对催化剂的晶体结构、光吸收性能、形貌性能进行了分析表征。以罗丹明B (Rh B)为模拟污染物,评价了该催化剂的可见光催化性能。结果表明,RGO和Au纳米颗粒的引入,增强了Bi_2WO_6可见光吸收,同时抑制了光生载流子的复合,从而提高Bi_2WO_6可见光催化降解RhB的性能。     

溶胶-凝胶法制备TiO2/PMMA纳米复合材料的研究

通过溶胶-凝胶法制备了TiO2溶胶,与聚甲基丙烯酸甲酯(PMMA)进行杂化处理制得了TiO2/PMMA纳米复合材料.并将不同量的溶胶与几种不同摩尔质量的PMMA进行复合,得到多种样品.通过透射电镜(TEM)、红外光谱(FTIR)、紫外-可见光谱(UV-Vis)、热失重(TGA)分析研究了TiO2/PMMA纳米复合材料的结构和性能,从而由溶胶含量、PMMA摩尔质量等不同因素对复合材料性质产生的影响作出了解释.结果表明当溶胶含量为1％、PMMA的摩尔质量较低(37.3万g/mol)时,TiO2微粒在聚合物中的分散性较好,粒径较均一,TiO2的加入使得材料的抗紫外线性和热稳定性都有所提高.     

微波水热法制备稀土元素铒掺杂TiO_2光催化剂及光催化活性

采用微波水热法和溶胶-凝胶法制备稀土元素Er掺杂TiO_2光催化剂TiO_2-Er,以甲基橙溶液为模拟污染物,在微波辐射-紫外光照(MW-UV)和太阳光照条件下,考察TiO_2-Er光催化剂的光催化降解活性。分别用N_2吸附-脱附、ICP-AES和PL光谱分析对TiO_2-Er光催化剂进行结构测试和表征。结果表明,Er掺杂能显著提高TiO_2光催化剂光催化活性,微波水热法制备的TiO_2-Er光催化剂具有较高的光催化活性;微波水热法和溶胶-凝胶法制备的TiO_2-Er光催化剂微波辐射-紫外光照50 min,甲基橙降解率分别为100%和98.5%,太阳光照4 h,甲基橙降解率分别为99.0%和97.5%。微波水热法具有晶化时间短和元素掺杂均匀的优点,制备的TiO_2-Er光催化剂具有形貌均匀、孔径较大、孔分布均匀和比表面积较大等特点,且Er掺杂能抑制光生e~-/h~+复合,使光生e~-/h~+的分离效率得到提高,有利于光催化活性的提高。     

TiO2/BiVO4复合光催化剂的微波辅助水热法合成及催化性能研究

以硝酸铋和偏钒酸铵为原料,采用微波-辅助水热法合成了BiVO4和TiO2/BiVO4复合光催化剂,借助XRD、UV-Vis和FE-SEM等测试手段对样品进行表征。XRD分析表明,所得BiVO4粉体为单斜晶系,且与TiO2复合后,特征衍射峰宽化,强度降低;FE-SEM显示,所得样品为具有多级结构的球状纳米结构体系;UV-Vis吸收光谱表明,BiVO4粉体和TiO2/BiVO4在400～600 nm的可见光区域对光响应。根据光吸收特性,选择罗丹明B为模型污染物,考察了样品可见光催化活性。结果表明,TiO2/BiVO4相比BiVO4,具有更高的可见光催化活性。     

Tb掺杂介孔TiO_2/聚噻吩复合材料的制备及其可见光光催化性能研究

采用原位聚合法制备了一系列不同质量比m(Th)/m(Tb掺杂介孔TiO2)的复合光催化剂(其中Th为噻吩),采用XRD、FTIR、荧光光谱(PL)、场发射透射电镜(FETEM)和X射线光电子能谱(XPS)对复合光催化剂进行了表征。结果表明,复合粒子上的聚噻吩骨架中S原子与TiO2粒子间存在相互作用。以罗丹明B为模型降解物,研究了不同比例复合光催化剂在可见光下的光催化性能,其中m(Th)/m(Tb掺杂介孔TiO2)=1/10复合光催化剂光催化性能最好。在可见光照射下4 h,脱色率达到82.4%。这是由于Tb掺杂介孔TiO2与PTh(聚噻吩)之间的协同作用,拓宽了TiO2纳米粒子的光响应范围,提高了光生电子和空穴的分离效率,从而有效提高了其光催化性能。     

Preparation, characterization and photocatalytic activity of Si-doped and rare earth-doped TiO2 from mesoporous precursors

Si-doped and rare earth-doped TiO₂ with large specific surface area were prepared by the hydrothermal method and sol–gel route, respectively, using C₁₈H₃₇NH₂ as template. The samples were characterized by XRD, FT-IR, low-temperature N₂ adsorption–desorption measurement, XPS and solid state UV–vis diffuse reflectance spectroscopy. The pore size for Si-doped TiO₂ exhibits both mesoporous and microporous distribution, and that for rare earth-doped TiO₂ exhibits a sharp and narrow distribution in microporous range. The photocatalytic activities were investigated with the degradation of phenol as probe reaction. Compared with pure TiO₂, the conversion of phenol and selectivity to CO₂ increases when adding rare earth elements, and the substitution of Si for Ti in an appropriate range also increases the conversion of phenol.     

Ag/TiO2光催化降解茜素红

以钛酸四丁酯为前驱体,冰醋酸为水解抑制剂,用溶胶-凝胶法制备了纳米Ag/TiO₂复合催化剂,测定了催化剂对茜素红溶液的光降解活性。结果表明,Ag/TiO₂催化剂具有较高的光催化活性。     

钛硅复合氧化物介孔材料在光催化降解罗丹明B中的应用

采用溶胶凝胶法以硫酸氧钛和水玻璃为前驱体制备二氧化钛-二氧化硅复合氧化物，利用XRD、SEM、TEM、BET、激光粒度仪、紫外-可见光谱等测试方法对二氧化钛-二氧化硅复合氧化物材料进行了测试分析，考察了制备条件对二氧化钛-二氧化硅复合氧化物材料的晶相、形貌、孔结构、粒度等物理性质的影响规律，并对其在紫外光区降解罗丹明B（RhB）溶液的性能进行了研究。结果表明：二氧化钛-二氧化硅复合氧化物具有优良的催化活性，其光催化活性明显优于市售的P25二氧化钛，焙烧温度对催化剂性能影响最大。     

Simple microwave synthesis of TiO2/NiS2 nanocomposite and TiO2/NiS2/Cu nanocomposite as an efficient visible driven photocatalyst

Approximately 47% of solar-terrestrial radiation is visible. It is a great achievement to produce a highly efficient visible driven photocatalyst. Here TiO₂/NiS₂/Cu nanocomposite was prepared as a highly active visible driven photocatalyst. TiO₂/NiS₂/Cu nanocomposite was prepared by microwave method. It degrades 92%, 86%, 87%, and 88% of Rhodamine B (RhB), Methyl orange (MO), Acid Black 1 (AB1), and Acid Brown 214 (AB214), respectively. Adding NiS₂ and Cu to TiO₂ dramatically increased the degradation efficiency from 17% for bare TiO₂ to 92% for TiO₂/NiS₂/Cu nanocomposite under visible light. As-prepared TiO₂/NiS₂/Cu nanocomposite was characterized by SEM, TEM, XRD, DRS, BET, and EDX.     

超细TiO_2粒子的溶胶凝胶法制备研究

用溶胶凝胶法制备了不同性状的超细TiO2粒子,研究了影响产物性能的主要因素。结果表明,通过对体系pH值、酯醇比、烧结温度等因素的控制,可制得所需要的TiO2超细粒子。     

Sol-gel法制备悬浮型TiO2纳米微粒

采用Sol-gel法制备了悬浮型TiO2纳米微粒。用GC研究了不同烧结温度及不同Sol-gel制备参数条件下制备的TiO2对苯系物降解效率的影响，并用XRD和FEM对制备的纳米TiO2微粒进行了表征。研究结果表明，制备的悬浮型TiO2具有对有机污染物降解效率高等优点，是一种具有晶粒尺寸小的纳米微粒。     

微波辐射法研制复合半导体光催化材料TiO2/ZnO

采用微波辐射法制备了复合型半导体光催化材料TiO2/ZnO,利用X射线衍射(XRD)测试技术对TiO2/ZnO复合型半导体光催化材料进行了表征。用甲基红模拟有机废水,在高压汞灯模拟日光光照的条件下,研究了复合型半导体光催化材料TiO2/ZnO光催化降解有机废水的过程,并在相同的条件下,与机械研磨法制备的复合型半导体光催化材料TiO2/ZnO的光催化性能进行了对比实验。研究结果表明,微波辐射法制备的复合型半导体光催化材料TiO2/ZnO具有很好的光催化性能,TiO2/ZnO投加量为0.5g.L-1时,其具有良好的光催化脱色性能,经1h光照,对甲基红的光降解效率可以达到100%。随着溶液初始浓度增加,甲基红的降解率增大。     

Mesoporous Ag2O/ZrO2 heterostructures as efficient photocatalyst for acceleration photocatalytic oxidative desulfurization of thiophene

The production of fuels with a low sulfur content has been paid significant attention in the manufacturing of petroleum refining due to the progressively severe environmental legislations obliged by governments worldwide. In this paper, for the first time, two dimensional mesoporous Ag₂O/ZrO₂ heterostructures were synthesized by a facile approach for thiophene photocatalytic oxidative desulfurization under visible-light exposure at room temperature. The Ag₂O/ZrO₂ heterostructures significantly enhanced the photocatalytic desulfurization of thiophene obeyed the pseudo-first-order model compared to pristine ZrO₂ NPs. In particular, 1.5%Ag₂O/ZrO₂ photocatalyst exhibited better photocatalytic performance and the correspondent rate constant of 0.0235 min^?1, which was promoted 5.35 times than that of pristine ZrO₂ NPs (0.0044 min^?1). The desulfurization rate of thiophene over 1.5% Ag₂O/ZrO₂ heterostructure was enhanced 3.7 times larger than that of pristine ZrO₂ NPs. The thiophene was photocatalytically oxidized to CO₂ and SO₃. The photocatalytic performance of Ag₂O/ZrO₂ could be enhanced because of its synergetic effects, the intense visible-light harvest, rapid mobility of the thiophene to the active sites, a lower light scattering effect, and a large ^?OH radical contents formed. Moreover, the Ag₂O/ZrO₂ heterostructures revealed excellent stability toward the photocatalytic oxidative desulfurization of thiophene. A possible charge separation mechanism over mesoporous Ag₂O/ZrO₂ heterostructures was proposed.