采用硅酸钠和正硅酸乙酯 (TEOS)两种硅源作为前驱体,钛酸丁酯 (TBOT)为钛源,氢氟酸 (HF)为催化剂,在低温下合成了SiO2/F-TiO2光催化剂。通过场发射扫描电子显微镜,X射线衍射,光致发光光谱、氮吸附-脱附量和孔径分布、紫外-可见漫反射光谱等测试,分析了合成的催化剂的微观结构、晶形变化、光吸收阈值和禁带宽度、比表面积和孔径分布、电子-空穴对的重组情况等特性。通过模拟太阳光下罗丹明B的降解评价了所制备催化剂的光催化活性,通过添加不同的捕获剂对其光催化机理进行了探讨。结果表明:SiO2的引入改变了F-TiO2的微观结构和晶形,使其禁带宽度从2.82eV降至2.73eV,比表面积从86.316m2/g增加到115.638m2/g。0.03g Ti∶Si=4∶1的SiO2/F-TiO2在2h内对10mg/L罗丹明B的降解率可达98.3%。超氧自由基 (O2·-)在光催化过程中起主要作用。
Sodium silicate and tetraethyl orthosilicate (TEOS) were used as Si precursors,butyl titanate (TBOT) as titanium source,and hydrofluoric acid (HF) as catalyst to synthesize SiO2/F-TiO2 photocatalysts at low temperature.The microstructure,crystal shape change,absorption threshold and forbidden band width,specific surface area and pore size distribution,recombination of electron-hole pairs of the as-prepared catalysts were measured by field emission scanning electron microscopy,X-ray diffraction,photoluminescence spectroscopy,nitrogen adsorption-desorption amount and pore size distribution,UV-visible diffuse reflectance spectroscopy characterization tests.The photocatalytic activity of the catalyst was evaluated by photocatalytic degradation of rhodamine B under simulated sunlight.The photocatalytic mechanism was investigated by adding different capture agents.The results shown that the surface fluorination and the introduction of SiO2 changed the microstructure and crystal form of F-TiO2.The addition of SiO2 reduced the forbidden band width of the photocatalyst from 2.82eV to 2.73eV,and the specific surface area increased from 86.316m2/g to 115.638m2/g.The degradation of 10mg/L rhodamine B for 0.03g Ti∶Si=4∶1 SiO2/F-TiO2 catalyst can be as high as 98.3% in 2h.The superoxide radical (O2·-) played a major role in photocatalytic activity.
[1] Nunes D,Pimentel A,Santos L,et al.Photocatalytic TiO2 nanorod spheres and arrays compatible with flexible applications[J].Catalysts,2017,7 (2):60.
[2] Zhang Ying,Chen Juanrong,Tang Hua,et al.Hierarchically-structured SiO2-Ag@TiO2 hollow spheres with excellent photocatalytic activity and recyclability[J].Journal of Hazardous Materials,2018,354:17-26.
[3] Wan Hengcheng,Yao Weitang,Zhu Wenkun,et al.Fe-N co-doped SiO2@TiO2 yolk-shell hollow nanospheres with enhanced visible light photocatalytic degradation[J].Applied Surface Science,2018,444:355-363.
[4] Xie Chong,Yang Shenghui,Shi Jianwen,et al.Highly crystallized C-doped mesoporous anatase TiO2 with visible light photocatalytic activity[J].Catalysts,2016,6:117.
[5] Zhang Ying,Zhao Zhiyuan,Chen Juanrong,et al.C-doped hollow TiO2 spheres:in situ synthesis,controlled shell thickness,and superior visible-light photocatalytic activity[J].Applied Catalysis B:Environmental,2015,165:715-722.
[6] Zhang Ying,Chen Juanrong,Li Hua,et al.High photocatalytic activity of hierarchical SiO2@C-doped TiO2 hollow spheres in UV and visible light towards degradation of rhodamine B[J].Journal of Hazardous Materials,2017,340:309-318.
[7] Minero C,Catozzo F,Pelizzetti E.Role of adsorption in photocatalyzed reactions of organic molecules in aqueous titania suspensions[J].Langmuir,1992,8 (2):481-486.
[8] Cheng S,Tsai S,Lee Y.Photocatalytic decomposition of phenol over titanium oxide of various structures[J].Catalysis Today,1995,26 (1):87-96.
[9] Pal A,Jana T,Chatterjee K.Silica supported TiO2 nanostructures for highly efficient photocatalytic application under visible light irradiation[J].Materials Research Bulletin,2016,76:353-357.
[10] Bera S,Rawal S,Kim H,et al.Novel coupled structures of FeWO4/TiO2 and FeWO4/TiO2/CdS designed for highly efficient visible-light photocatalysis[J].ACS Appl Mater Interfaces,2014,6 (12):9654-9663.
[11] Kocí K,Relia M,Edelmannová M,et al.Photocatalytic hydrogen production from methanol over Nd/TiO2[J].Journal of Photochemistry and Photobiology A:Chemistry,2018,366:55-64.
[12] Stets S,Amaral B,Schneider J S,et al.Antituberculosis drugs degradation by UV-based advanced oxidation processes[J].Journal of Photochemistry and Photobiology A:Chemistry,2018,353:26-33.
[13] 陈秀琴,张兴旺,雷乐成.F掺杂TiO2纳米管阵列可见光催化活性和电子结构[J].无机材料学报,2011,26 (4):369-374.
[14] Police A,Basavaraju S,Valluri D,et al.CaFe2O4 sensitized hierarchical TiO2 photo composite for hydrogen production under solar light irradiation[J].Chemical Engineering Journal,2014,247:152-160.
[15] Sun Hongqi,Zhou Guanliang,Liu Shizhen,et al.Visible light responsive titania photocatalysts codoped by nitrogen and metal (Fe,Ni,Ag,or Pt) for remediation of aqueous pollutants[J].Chemical Engineering Journal,2013,231:18-25.
[16] Hou Chentao,Liu Wenli.OH-TiO2/TiOF2 nanohybrids and their enhanced solar light photocatalytic performance[J].Royal Society Open Science,2018,5 (6):172005.
[17] Wang Huan,Yi Guobin,Tan Miao,et al.Initial reactant controlled synthesis of double layered TiO2 nanostructures and characterization of its spectra of absorption and photoluminescence[J].Materials Letters,2015,148:5-8.
[18] Li F,Li X.Photocatalytic properties of gold/gold ion-modified titanium dioxide for wastewater treatment[J].Applied Catalysis A:General,2002,228:15-27.
[19] Pinho L,Mosquera M.Photocatalytic activity of TiO2-SiO2 nanocomposites applied to buildings:influence of particle size and loading[J].Applied Catalysis B:Environmental,2013,134-135:205-221.
[20] 葛金龙,秦英月,邰燕芳,等.SiO2/TiO2复合材料的制备、表征及光催化罗丹明B的研究[J].化工新型材料,2017,45 (11):106-108,111.
[21] Chen C,Xu W,Charpentier P.SiO2 encapsulated TiO2 nanotubes and nanofibers for self-cleaning polyurethane coatings[J].Journal of Photochemistry and Photobiology A:Chemistry,2017,348:226-237.
[22] 刘潘.郭晓宁,南昊,等炉渣制光催化剂催化降解罗丹明B的机理[J].化工进展,2010,29 (6):1075-1079.
[23] Wu T,Lu G,Zhao J.Photoassisted degradation of dye pollutants.V.self-photosensitized oxidative transformation of rhodamineB under visible light irradiation in aqueous TiO2 dispersions[J].Phys Chem B,1998,102 (15):5845-5851.
[24] 李博,仙鸽,向延涛,等.低温制备二氧化钛纳米晶及其光催化性能研究[J].化学与黏合,2015,37 (6):436-436,457.
[25] Rodríguez E,Márquez G,Tena M,et al.Determination of main species involved in the first steps of TiO2 photocatalytic degradation of organics with the use of scavengers:the case of ofloxacin[J].Applied Catalysis B:Environmental,2015,178:44-53.
基金资助
陕西省工业攻关项目(2014GY2-07);陕西省教育厅项目(15JK1460)
PDF
(2697KB)
