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首页> 外文期刊>The journal of physical chemistry, B. Condensed matter, materials, surfaces, interfaces & biophysical >Spectral Dependencies of the Quantum Yield of Photochemical Processes on the Surface of Nano/Micro-Particulates of Wide-Band-Gap Metal Oxides. IV. Theoretical Modeling of the Activity and Selectivity of Semiconductor Photocatalysts with Inclusion of
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Spectral Dependencies of the Quantum Yield of Photochemical Processes on the Surface of Nano/Micro-Particulates of Wide-Band-Gap Metal Oxides. IV. Theoretical Modeling of the Activity and Selectivity of Semiconductor Photocatalysts with Inclusion of

机译：宽带隙金属氧化物的纳米/微粒表面上光化学过程的量子产率的光谱依赖性。 IV。包含ZnO的半导体光催化剂活性和选择性的理论模型。

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In an earlier study (Emeline, A. V.; Ryabchuk, V. K.; Serpone, N. J. Phys. Chem. B 1999, 103, 1316) we reported the solution to the continuity equation in which we neglected electric field effects and obtained expressions for the concentrations of the charge carriers at the surface (n_s), for the quantum yield (Φ) of a photochemical surface redox reaction, together with an expression for the selectivity of the photocatalyst. Various considerations led us to infer and predict wavelength-dependent phenomena (quantum yields and selectivity), which were later confirmed by experimental results (Emeline, A. V.; Serpone, N. J. Phys. Chem. B 2002, 106, 12221). In this article we revisit the continuity equation but include a subsurface electric field (E) in the space charge region of the semiconductor (or dielectric) photocatalyst to assess the effect that the electric field has on the activity and selectivity of the photocatalyst. The solution to the continuity equation yields very complex expressions for n_s and for Φ. Nonetheless, several cases are considered which simplify the expressions. Taking E = 0, the expression for the quantum yield transforms into the identical equation obtained earlier. Some of the predictions from the expressions obtained herein also find experimental verification from considerations, for example, of the quantum yields of photoadsorption of dioxygen and dihydrogen on TiO_2 particles. The agreement between the predicted spectral behavior of the ratio γ = [e_s]/[h_s] against wavelength with the spectral dependence of Φ_(O_2)/Φ_(H_2) is remarkable. Another no less significant conclusion from the theoretical modeling results is that a mismatch between the experimental spectral dependence of the quantum yield and the corresponding absorption band may be an indicator of the existence of a space charge region in the solid photocatalyst.
机译：在较早的研究中（Emeline，AV; Ryabchuk，VK; Serpone，NJ Phys。Chem。B 1999，103，1316），我们报告了连续方程的解，其中我们忽略了电场效应，并获得了有关浓度的表达式。用于光化学表面氧化还原反应的量子产率（Φ）的表面电荷（n_s）的电荷载流子，以及光催化剂选择性的表达式。各种考虑导致我们推断和预测波长依赖性现象（量子产率和选择性），随后由实验结果证实（Emeline，A.V。; Serpone，N.J.Phys.Chem.B 2002，106，12221）。在本文中，我们将回顾连续性方程，但在半导体（或电介质）光催化剂的空间电荷区域中包含一个亚表面电场（E），以评估电场对光催化剂的活性和选择性的影响。连续性方程的解对于n_s和Φ产生非常复杂的表达式。尽管如此，仍考虑了几种简化表达式的情况。假设E = 0，则量子产率的表达式将转化为先前获得的方程。从本文获得的表达式进行的一些预测还从例如考虑到TiO 2颗粒上双氧和双氢的光吸附的量子产率的考虑中找到实验验证。相对于波长的比率γ= [e_s] / [h_s]的预测光谱行为与Φ_（O_2）/Φ_（H_2）的光谱依赖性之间具有显着的一致性。从理论建模结果得出的另一个同样重要的结论是，量子产率的实验光谱依赖性与相应的吸收带之间的不匹配可能是固体光催化剂中存在空间电荷区域的指示。

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