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Excitation Wavelength Dependence of Photocatalyzed Oxidation of Methanol on TiO2(110)
Zhi-qiang Wang,Qun-qing Hao,Chuan-yao Zhou*,Dong-xu Dai,Xue-ming Yang*
Author NameAffiliationE-mail
Zhi-qiang Wang State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China  
Qun-qing Hao State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China  
Chuan-yao Zhou* State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China chuanyaozhou@dicp.ac.cn 
Dong-xu Dai State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China  
Xue-ming Yang* State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China xmyang@dicp.ac.cn 
Abstract:
Post-irradiation temperature-programmed desorption (TPD) has been used to study the photocatalyzed oxidation of methanol on TiO2(110) surface under the irradiation of 360, 380 and 400 nm light. The photocatalytic process initiated by ultraviolet light of different wavelength are similar. Methanol has been photocatalytically converted into formaldehyde, and the released hydrogen atoms transfer to the neighboring twofold coordinated oxygen to form bridging hydroxyls. The reaction rate, however, is strongly wavelength dependent. The reaction rate under 360 nm light irradiation is 4.8 times of that in the case of 400 nm exposure, consistent with a previous femtosecond time-resolved absorption measurement on TiO2 which shows the faster charge carrier recombination in the near-band-gap than the over-band-gap excitation. So far, the underlying factors which govern the excitation wavelength dependence of photocatalytic activity of TiO2 and other photocatalysts remain unclear, and future studies are needed to address this important issue.
Key words:  Titanium dioxide, Photocatalysis, Excitation wavelength dependence, Temperature-programmed desorption
FundProject:
甲醇在TiO2(110)表面光催化氧化的波长相关性
王志强,郝群庆,周传耀*,戴东旭,杨学明*
摘要:
用程序升温脱附谱的方法研究了甲醇在TiO2(110)表面光催化氧化的波长相关性.对于不同波长的激发光,甲醇光催化解离的产物相似,都是在光照的过程中通过O-H键和C-H键的断裂形成甲醛,解离出的氢原子转移到相邻的两配位的桥氧原子(Ob)上形成ObH.但是反应速率与激发光波长强烈相关.在360 nm光照下,甲醇的反应速率是400 nm光照时的4.8倍.这与以前使用时间分辨的飞秒激光吸收光谱测量的结果是一致的,他们认为近带隙激发和过带隙激发产生的电荷相比,前者的复合速率要远快于后者.
关键词:  二氧化钛,光催化,波长相关性,程序升温脱附谱
DOI:10.1063/1674-0068/28/cjcp1507147
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