Electron- and Hole-Capture Reactions on Pt/TiO2 Photocatalyst Exposed to Methanol Vapor Studied with Time-Resolved Infrared Absorption Spectroscopy
Electron- and Hole-Capture Reactions on Pt/TiO2 Photocatalyst Exposed to Methanol Vapor Studied with Time-Resolved Infrared Absorption Spectroscopy
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DOI：
10.1021/jp025993x
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发表时间：
2002-08
影响因子：
3.3
通讯作者：
Akira Yamakata;A. Ishibashi;H. Onishi
中科院分区：
文献类型：
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作者：
Akira Yamakata;A. Ishibashi;H. Onishi
用时间分辨红外吸收光谱（TR-IR）研究了Pt/TiO_2催化剂中光生电子的衰减动力学。暴露在甲醇蒸气中会极大地影响电子衰减，并阻止电子空穴对复合。有一部分电子保持在1 s以上，并从0.1 −9 s开始缓慢衰减。被阻止的重组被解释为空穴的有效捕获。空穴俘获的程度对甲醇蒸气的压力不敏感。通过对不同压力下甲醇蒸气作用下催化剂的稳态红外光谱分析，提出了不可逆吸附的甲氧基捕获空穴的机理。然而，电子的缓慢衰减表现出正阶响应的甲醇压力。未解离的甲醇的物理吸附和平衡的气相，这是确定在稳态光谱，应在电子捕获过程中发挥关键作用。可能的机制或…
The decay kinetics of photogenerated electrons in a Pt/TiO2 catalyst has been studied by time-resolved infrared absorption (TR-IR) spectroscopy. The electron decay was drastically affected by exposure to methanol vapor, and the electron−hole pair recombination was prevented. A certain fraction of the electrons remained beyond 1 s and slowly decayed from ∼1−9 s. The prevented recombination was interpreted with the effective capture of the holes. The extent of the hole capture was insensitive to the pressure of methanol vapor. An irreversibly adsorbed methoxy groups was proposed to capture the holes on the basis of the steady-state FT-IR spectra of the catalyst exposed to methanol vapor of different pressures. However, the slow decay of the electrons exhibited a positive-order response to the methanol pressure. Undissociated methanol physisorbed and equilibrated with the gas phase, which was identified in the steady-state spectra, should play a key role in the electron capture process. Possible mechanisms o...