Effect of the electronic state of Ti on M-doped TiO₂ nanoparticles (M=Zn, Ga or Ge) with high photocatalytic activities: A experimental and DFT molecular study

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• 作者：M. Salazar-Villanueva^a ; A. Cruz-Ló ; pez^b ; A.A. Zaldí ; var-Cadena^b ; A. Tovar-Corona^c ; M.L. Guevara-Romero^d ; O. Vazquez-Cuchillo^e ; ^{odilon_vazquez_c@hotmail.com}
• 关键词：X-ray photoelectron spectroscopy ; 2 ; 4-Dichlorophenoxyacetic acid ; Doping (Ga ; Ge ; Zn) ; TiO2 ; Density Functional Theory ; Quantum mechanics
• 刊名：Materials Science in Semiconductor Processing
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：58
• 期：Complete
• 页码：8-14
• 全文大小：1116 K
• 卷排序：58

文摘

In the pursuit of environmental sustainability, nanomaterials with specific characteristics that can improve the environment by various methods have been developed. In this work, M-doped TiO2 microspheres have been synthesized by a colloidal route and doped with 1% in wt. of M (M=Zn, Ga and Ge). The materials were calcined at 400 °C and they were characterized by means X-ray diffraction (XRD) analysis, UV–vis spectroscopy coupled with diffuse reflectance spectroscopy (DRS), N2 physisorption, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The catalytic activity of the materials was studied by evaluating the photocatalytic degradation of 2,4-dichlorophenoxyacetic acid in an aqueous solution. Moreover the photocatalytic activity of the doped materials were enhanced compared to pristine material, according the next trend:Ge:TiO2 >Ga:TiO2 >Zn:TiO2>TiO2. The presence of atoms of Zn, Ga or Ge in the structure of TiO2 was shown by XPS analysis, indeed these results reveal a diminution of the energy levels of the 2p3/2 and 2p1/2 electrons from doped materials compared with pristine material, which is evidence for a strong relationship between the doped cation valence of the TiO2 and the degradation of the 2,4-dichlorophenoxyacetic acid. Theoretical calculations within DFT framework were performed on two models of nanoparticles like-anatase in order to interpret the photocatalytic activity obtained experimentally by means the frontier orbitals (HOMO and LUMO), the morphology and electronic distribution.