The nature of defects in fluorine-doped TiO2
The nature of defects in fluorine-doped TiO2
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DOI：
10.1021/jp8004184
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发表时间：
2008-06-19
影响因子：
3.7
通讯作者：
Pacchioni, G.
中科院分区：
文献类型：
--
作者：
Czoska, A. M.;Livraghi, S.;Pacchioni, G.
采用溶胶-凝胶法制备了氟掺杂二氧化钛粉体。在晶格中的氟的存在下诱导形成的还原Ti（3+）的中心，本地化的额外的电子需要的电荷补偿，并观察到电子顺磁共振。用杂化泛函的密度泛函理论计算与这种描述完全一致。额外的电子高度定位在钛的3d轨道中，位于导带底部以下十分之几个电子伏。通过使用氟化物水溶液的溶胶-凝胶合成的制备也导致表面F（-）离子的形成，其取代表面羟基（OH（-））而不产生还原中心。
Fluorine-doped titanium dioxide was prepared via sol-gel synthesis and subsequent calcination in air. The presence of fluorine in the lattice induces the formation of reduced Ti(3+) centers that localize the extra electron needed for charge compensation and are observed by electron paramagnetic resonance. Density functional theory calculations using hybrid functionals are in full agreement with such description. The extra electron is highly localized in a 3d orbital of titanium and lies a few tenths of an electron volt below the bottom of the conduction band. The preparation via sol-gel synthesis using aqueous solutions of fluorides also causes the formation of surface F(-) ions that substitute surface hydroxyl groups (OH(-)) without generating reduced centers.