Photocatalytic Dissociation of Ethanol on TiO2(110) by Near-Band-Gap Excitation

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• 作者：Zhibo Ma ; Qing Guo ; Xinchun Mao ; Zefeng Ren ; Xu Wang ; Chenbiao Xu ; Wenshao Yang ; Dongxu Dai ; Chuanyao Zhou ; Hongjun Fan ; Xueming Yang
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：May 23, 2013
• 年：2013
• 卷：117
• 期：20
• 页码：10336-10344
• 全文大小：440K
• 年卷期：v.117,no.20(May 23, 2013)
• ISSN：1932-7455

文摘

Ethanol on TiO₂(110) has been studied using the temperature-programmed desorption (TPD), femtosecond two-photon photoemission spectroscopy (2PPE), and density functional theory (DFT) calculations. The first layer of ethanol (binds to Ti_5c) whose molecular state has been predicted to be more stable by DFT desorbs at 295 K. A photoinduced excited state that is associated with bridging hydroxyls has been detected at 2.4 eV above the Fermi level on ethanol/TiO₂(110) interface using 2PPE. Detailed TPD studies show that ethanol on Ti_5c can be photocatalytically converted to acetaldehyde by near-band-gap excitation with the hydrogen atoms transfer to bridging-bonded oxygen sites, which is consistent with the 2PPE results. TPD results also show a low-temperature water TPD peak that seems to bind to the Ti_5c sites in addition to the ethylene TPD product. These results suggest that the Ti_5c sites on TiO₂(110) are the primary active sites for photocatalysis of ethanol on TiO₂(110), while bridging-bonded oxygen sites also play an important role, as in the case of methanol. The kinetics of photocatalyzed ethanol dissociation on TiO₂(110) has also been measured using the 2PPE technique, which is of heterogeneous nature.