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Microwave-assisted sol-gel synthesis of TiO2 in the presence of halogenhydric acids. Characterization and photocatalytic activity
Journal of Photochemistry and Photobiology A: Chemistry ( IF 4.1 ) Pub Date : 2020-02-28 , DOI: 10.1016/j.jphotochem.2020.112457
F. Puga , J.A. Navío , C. Jaramillo-Páez , P. Sánchez-Cid , M.C. Hidalgo

The synthesis of mesoporous TiO2 nanosheets is reported using Ti(IV) Isopropoxide as Ti(IV) precursor. A sol-gel process combined with microwave activation is used. Three different halogenhydric acids (HX), were used to peptise the sol: HF(ac), HCl (ac) and HBr (ac). The three obtained TiO2-I(HX) samples were characterized by XRD, XRF, N2-adsorption, SEM, TEM, DRS and XPS. The three synthesized samples have high values of specific surfaces (between 100 m2/g and 200 m2/g) and similar band gap values (3.2–3.3 eV). The analysis of the surface composition by XPS confirms the presence of the halogenated species (F, Cl or Br) on the surface of each ones of the samples. The nanometric size (ca 5 nm) of the particles for each of the three samples was confirmed by XRD and by TEM. On the other hand, the nature of the halogenated acid used plays a role in the composition of the phases. While the TiO2-I (HF) sample was 100 % anatase, the other samples turned out to be biphasic, showing anatase/rutile in the TiO2-I(HCl) sample and anatase/brookite in the TiO2-I(HBr) sample. The samples were tested under two illumination conditions (UV and visible light) using rhodamine B and caffeine. The indirect role of the halide agent on the photocatalytic activities thereof is discussed.



中文翻译:

在卤代酸存在下微波辅助溶胶-凝胶法合成TiO 2。表征和光催化活性

报道了使用异丙醇钛(IV)作为钛(IV)前体的介孔TiO 2纳米片的合成。使用结合了微波活化的溶胶-凝胶工艺。三种不同的卤代氢酸(HX)用于胶溶该溶胶:HF(ac),HCl(ac)和HBr(ac)。通过XRD,XRF,N 2吸附,SEM,TEM,DRS和XPS对得到的三个TiO 2 -I(HX)样品进行了表征。这三个合成样品具有较高的比表面积值(介于100 m 2 / g和200 m 2 / g之间)和相似的带隙值(3.2–3.3 eV)。通过XPS对表面成分的分析证实了每个样品表面上都存在卤化物质(F,Cl或Br)。该纳米尺寸(CA通过XRD和TEM确认了三个样品中每个样品的5 nm)颗粒。另一方面,所使用的卤代酸的性质在相的组成中起作用。TiO 2 -I(HF)样品为100%锐钛矿,其他样品证明是双相的,在TiO 2 -I(HCl)样品中显示为锐钛矿/金红石,在TiO 2 -I(HBr )中显示为锐钛矿/板钛矿)样本。使用若丹明B和咖啡因在两种照明条件(紫外线和可见光)下测试了样品。讨论了卤化物对其光催化活性的间接作用。

更新日期:2020-02-28
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