Role of Water in Methanol Photochemistry on Rutile TiO2(110)
Role of Water in Methanol Photochemistry on Rutile TiO2(110)
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DOI：
10.1021/jp3046774
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发表时间：
2012-08
影响因子：
3.7
通讯作者：
Mingmin Shen;M. A. Henderson
中科院分区：
文献类型：
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作者：
Mingmin Shen;M. A. Henderson
用程序升温脱附(TPD)技术研究了甲醇在真空热处理的金红石型二氧化钛(110)表面上的分子吸附和解离吸附的光化学行为。甲氧基，而不是甲醇，被确认为吸附在该表面上的甲醇的光化学活性形式。在紫外光照射下，甲氧基覆盖的二氧化钛(110)表面甲氧基被耗尽，并形成甲醛和表面羟基。共吸附水对分子甲醇光化学和甲醇热分解为甲氧基均无促进作用。然而，通过水原子和氧原子的共吸附制备的末端羟基(OHT)在120K时将吸附在分子上的甲醇热转化为甲氧基，从而实现了光活性。化学吸附的水分子对甲氧基光化学没有影响，第二层中的水分子与氧(OBR)桥位的氢键抑制了甲氧基光分解为甲醛。从这个开始，我们..。
Photochemistry of the molecularly and dissociatively adsorbed forms of methanol on the vacuum-annealed rutile TiO2(110) surface was explored using temperature-programmed desorption (TPD) both with and without coadsorbed water. Methoxy, and not methanol, was confirmed as the photochemically active form of adsorbed methanol on this surface. UV irradiation of methoxy-covered TiO2(110) led to depletion of the methoxy coverage and to formation of formaldehyde and a surface OH group. Coadsorbed water did not promote either molecular methanol photochemistry or thermal decomposition of methanol to methoxy. However, terminal OH groups (OHt), prepared by coadsorption of water and oxygen atoms, thermally converted molecularly adsorbed methanol to methoxy at 120 K thus enabling photoactivity. While chemisorbed water molecules had no influence on methoxy photochemistry, water molecules hydrogen-bonded in the second layer to bridging oxygen (Obr) sites inhibited methoxy photodecomposition to formaldehyde. From this, we...