Simple Photocatalysis Model for Photoefficiency Enhancement via Controlled, Periodic Illumination
Simple Photocatalysis Model for Photoefficiency Enhancement via Controlled, Periodic Illumination
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通过受控周期性照明提高光效率的简单光催化模型
DOI：
10.1021/jp962649p
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发表时间：
1997
影响因子：
3.3
通讯作者：
D. Ollis
中科院分区：
文献类型：
--
作者：
Santosh Upadhya and;D. Ollis
在稳定照明下，使用二氧化钛的水相光催化氧化反应特征性地表现出低量子产率，即，在该过程中入射光的使用效率很低。Sczechowski、Koval和Noble 1报告了在流动系统中使用受控的周期性照明而不是连续照明时，TiO 2的光效率（定义为反应速率除以入射光子速率）显著更高。我们提出了一个瞬态动力学模型，该模型表明，光生空穴（或其氧化产物OH自由基等）对预吸附反应物的快速消耗。解释了在周期性照射下如此高的光效率，并且额外的氧的特征性缓慢吸附和/或电子转移到氧是在稳定照射下观察到的低量子产率的原因。一个模型模拟提供的光效率的变化趋势与类似的观察到的光暗周期的长度。
Under steady illumination, aqueous phase photocatalytic oxidation reactions using titanium dioxide characteristically exhibit low quantum yields, i.e., the incident light is used inefficiently in the process. Sczechowski, Koval, and Noble1 reported substantially higher photoefficiencies (defined as reaction rate divided by incident photon rate) for TiO2 while using controlled, periodic illumination instead of continuous illumination in a flow system. We propose a transient kinetic model which suggests that rapid consumption of preadsorbed reactant inventory by photoproduced holes (or by their oxidation product, OH radical, etc.) accounts for such high photoefficiencies with periodic illumination and that the characteristically slow adsorption of additional oxygen and/or electron transfer to oxygen is responsible for low quantum yields observed under steady illumination. A model simulation provides trends of photoefficiency with variation of the length of light and dark periods which resemble the observed ...