Kinetics and Mechanism of Methanol Conversion over Anatase Titania Nanoshapes
Kinetics and Mechanism of Methanol Conversion over Anatase Titania Nanoshapes
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DOI：
10.1021/acscatal.7b01456
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发表时间：
2017-07
期刊：
影响因子：
12.9
通讯作者：
Guo Shiou Foo;Guoxiang Hu;Zachary D. Hood;M. Li;D. Jiang;Zili Wu
中科院分区：
文献类型：
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作者：
Guo Shiou Foo;Guoxiang Hu;Zachary D. Hood;M. Li;D. Jiang;Zili Wu
为了了解TiO2的表面结构效应，研究了在300°C、稀氧条件下，锐钛矿型TiO2纳米板和截尖双锥体纳米晶体上甲醇脱水、氧化还原和氧化偶联的动力学和机理。两种TiO2纳米形状均显示（001）和（101）面，其中（001）面暴露在纳米板上的比例较高，而截形双锥体纳米晶体则以（101）面为主。用氨原位滴定法进行的动力学研究表明，与氧化还原和氧化偶联相比，甲醇脱水的活性位点是酸性的和不等效的。原位FTIR光谱分析表明，吸附的甲氧基是所有反应的主要表面物质，而观察到的甲醇二聚体通过甲醇同位素交换被发现是一个旁观者物质，支持了甲醇通过表面甲氧基在TiO2表面脱水的解离机制。密度泛函理论计算表明……
The kinetics and mechanism of methanol dehydration, redox, and oxidative coupling were investigated at 300 °C under dilute oxygen concentration over anatase TiO2 nanoplates and truncated-bipyramidal nanocrystals in order to understand the surface structure effect of TiO2. The two TiO2 nanoshapes displayed both (001) and (101) facets, with a higher fraction of the (001) facet exposed on the nanoplates, while truncated-bipyramidal nanocrystals were dominated by the (101) facet. A kinetic study using in situ titration with ammonia shows that the active sites for methanol dehydration are acidic and nonequivalent in comparison to redox and oxidative coupling. In situ FTIR spectroscopy reveals that adsorbed methoxy is the dominant surface species for all reactions, while the observed methanol dimer is found to be a spectator species through isotopic methanol exchange, supporting the dissociative mechanism for methanol dehydration via surface methoxy over TiO2 surfaces. Density functional theory calculations sho...