Comprehensive Kinetic and Mechanistic Analysis of TiO2 Photocatalytic Reactions According to the Direct-Indirect Model: (I) Theoretical Approach
Comprehensive Kinetic and Mechanistic Analysis of TiO2 Photocatalytic Reactions According to the Direct-Indirect Model: (I) Theoretical Approach
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DOI：
10.1021/jp4121645
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发表时间：
2014-07-03
影响因子：
3.7
通讯作者：
Salvador, Pedro
中科院分区：
文献类型：
--
作者：
Montoya, Juan Felipe;Peral, Jose;Salvador, Pedro
半导体气相和液相悬浮液中有机物的光催化氧化动力学，强烈依赖于基质物质与半导体表面的电子相互作用强度。根据直接-间接（D-I）模型，该模型作为Langmuir-Hinshelwood（L-H）模型的替代方案而开发（萨尔瓦多，P.等Catalysis Today 2007，129，247），当溶解的底物物质的化学吸附不受欢迎并且物理吸附是唯一存在的吸附机制时，界面空穴转移通过间接转移（IT）机制发生，光氧化速率指数地取决于入射光子通量（V-ox = V-ox（IT）与rho（n）成比例），其中在足够高的光子通量（标准实验条件）下n = 1/2，无论溶解的底物浓度如何[（RH 2）（liq）]。相比之下，在同时物理吸附和化学吸附基质物质的情况下，空穴捕获经由间接转移（IT）和直接转移（DT）机制的组合（V-ox = V-ox（IT）+ V-ox（DT））发生，其中对于足够低的p值，V-ox（DT）与rho（n）成比例，并且n = 1，只要吸附-解吸平衡
The photocatalytic oxidation kinetics of organic species in semiconductor (sc) gas phase and liquid semiconductor suspensions, strongly depends on the electronic interaction strength of substrate species with the sc surface. According to the Direct-Indirect (D-I) model, developed as an alternative to the Langmuir-Hinshelwood (L-H) model (Salvador, P. et al. Catalysis Today 2007, 129, 247), when chemisorption of dissolved substrate species is not favored and physisorption is the only existing adsorption mechanism, interfacial hole transfer takes place via an indirect transfer (IT) mechanism, the photooxidation rate exponentially depending on the incident photon flux (V-ox = V-ox(IT) proportional to rho(n)), with n = 1/2 under high enough photon flux (standard experimental conditions), whatever the dissolved substrate concentration, [(RH2)(liq)]. In contrast, under simultaneous physisorption and chemisorption of substrate species, hole capture takes place via a combination of an indirect transfer (IT) and a direct transfer (DT) mechanism (V-ox = V-ox(IT) + V-ox(DT)) with V-ox(DT) proportional to rho(n) and n = 1 for low enough p values, as long as adsorption-desorption equilibrium