Synergetic effects of lanthanum, nitrogen and phosphorus tri-doping on visible-light photoactivity of TiO₂ fabricated by microwave-hydrothermal process

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• 作者：Hongquan JIANG (姜洪泉) ; ^{h.q.jiang1119@163.com" class="auth_mail" title="E-mail the corresponding author} ; Yanduo LIU (刘彦铎) ; Jingshen LI (李井申) ; Haiyan WANG (王海燕)
• 关键词：TiO2 ; tri-doping ; microwave-hydrothermal ; visible-light photoactivity ; synergetic effect ; rare earths
• 刊名：Journal of Rare Earths
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：34
• 期：6
• 页码：604-613
• 全文大小：1874 K

文摘

Effects of La, N, and P doping on the structural, electronic and optical properties of TiO₂ synthesized from TiCl₄ hydrolysis via a microwave-hydrothermal process were investigated by X-ray diffraction, transmission electron microscopy, N₂ adsorption-desorption isotherm, X-ray photoelectron spectroscopy, electron paramagnetic resonance, UV-vis absorbance spectroscopy, photoelectrochemical measurements, and photoluminescence spectroscopy. The results showed that the presence of La in the tri-doped TiO₂ played a predominant role in inhibiting the recombination of the photogenerated electrons and holes. The existence of the substitutional N, interstitial N, and oxygen vacancies in TiO₂ lattices led to the band gap narrowing. It was P-doping rather than La or N doping that played a key role in inhibiting both anatase-to-rutile phase transformation and crystal growth, in stabilizing the mesoporous textural properties, and in increasing the content of surface bridging hydroxyl. Moreover, the tri-doping significantly enhanced the surface Ti⁴⁺–O^2––Ti⁴⁺–O^−• species. All above-mentioned factors cooperated to result in the enhanced photoactivity of the tri-doped TiO₂. As a result, it exhibited the highest photoactivity towards the degradation of 4-chlorophenol (4-CP) under visible-light irradiation among all samples, which was much superior to commercial P25 TiO₂.