悬空债券
光催化
X射线光电子能谱
电子
带隙
导带
工作职能
极化(电化学)
材料科学
Atom(片上系统)
化学
化学物理
纳米技术
光电子学
物理化学
核磁共振
物理
硅
催化作用
嵌入式系统
量子力学
生物化学
计算机科学
图层(电子)
作者
Lei Li,Hongwei Tian,Fanling Meng,Xiaoying Hu,Weitao Zheng,Chang Q. Sun
标识
DOI:10.1016/j.apsusc.2014.08.078
摘要
Defect generation forms an important means modulating the photocatalytic ability of TiO2 with mechanisms that remain yet unclear. Here we show that a spectral distillation clarifies the impact of defect on modulating the band gap, electroaffinity, and work function of the substance. Firstly, by analyzing XPS measurements, we calibrated the 2p3/2 level of 451.47 eV for an isolated Ti atom and its shifts by 2.14 and 6.94 eV, respectively, upon Ti and TiO2 bulk formation. Spectral difference between the defected and the un-defected TiO2 skin revealed then that the 2p3/2 level shifts further from 6.94 to 9.67 eV due to the defect-induced quantum entrapment. This entrapment is associated with an elevation of the upper edges of both the 2p3/2 and the conduction band by polarization. The shortening and strengthening of bonds between undercoordinated atoms densify and entrap the core electrons, which in turn polarize the dangling bond electrons of defect atoms. The entrapment and polarization mediate thus the band gap, the electroaffinity, the work function, and the photocatalytic ability of TiO2.
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