Effects of vanadium doping on microstructures and optical properties of TiO₂

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• 作者：Tong Wang ; Tao Xu ; ^{seuxt@163.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Titanium dioxide ; Vanadium doping ; Optical properties ; Photocatalytic activity
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：43
• 期：1
• 页码：1558-1564
• 全文大小：819 K

文摘

To improve the photocatalytic activity of titanium dioxide (TiO₂), the vanadium (V) was selected to modify TiO₂. Pure and V-doped TiO₂ samples were first synthesized, then effects of the V doping on microstructures and optical properties of TiO₂ were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and high resolution TEM (HRTEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible light diffuse reflectance spectra (UV–vis DRS). Results indicated that the prepared TiO₂ samples only contained anatase phase. The V dopant was uniformly dispersed in TiO₂ lattices, not affecting the crystal phase structures of TiO₂. The crystallite sizes of TiO₂ were decreased first and then increased with the increase in V dopant content within the diameter range from 12 to 16 nm. The V dopant inhibited the increase in TiO₂ crystallite size. Also, the dispersity of TiO₂ nanoparticles was improved with the increase in V dopant content. The V doping brought more defects in TiO₂ lattices to capture charge carriers, and to decrease the recombination of electron–hole pairs. Additionally, the prepared TiO₂ included such elements as Ti, V and oxygen (O). V consisted of two chemical states of V⁴⁺ and V⁵⁺, which were served as trapping centers of photo-generated electrons to promote the photocatalytic oxidation process. Ti existed in the form of Ti⁴⁺, and O presented in the form of such chemical bonds as Ti-O, Ti-OH and Ti-O-V in V-doped TiO₂. Finally, the optical absorption edges of V-doped TiO₂ show obvious red shift. The optimal V dopant content is 1.0% for pure TiO₂ sample. The V dopant could introduce the doping energy level and narrow the band gap of TiO₂, extending the absorption spectral range of TiO₂. The V doping was an effective method to improve optical absorption properties of TiO₂ in visible light region.