On the True Photoreactivity Order of {001}, {010}, and {101} Facets of Anatase TiO2 Crystals
On the True Photoreactivity Order of {001}, {010}, and {101} Facets of Anatase TiO2 Crystals
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关于锐钛矿型 TiO2 晶体 {001}、{010} 和 {101} 面的真实光反应顺序
DOI：
10.1002/anie.201006057
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发表时间：
2011-01-01
影响因子：
16.6
通讯作者：
Cheng, Hui-Ming
中科院分区：
文献类型：
--
作者：
Pan, Jian;Liu, Gang;Cheng, Hui-Ming
晶面的设计和形态控制是优化从贵金属到半导体的各种晶体催化剂的性能的常用策略。[1-8]这种策略的基础是，表面原子的配置和协调，这内在地决定了它们的异质反应性，可以通过形态控制进行微调。[3]对晶体表面原子结构的传统理解是，具有较高比例的配位不足原子的小面通常在非均相反应中更具反应性。例如，作为最重要的光催化剂之一的TiO 2的{001}晶面[9-17]被认为比{101}晶面更具反应性。通过研究一组具有主要{001}、{101}或{010}晶面的单晶，我们发现，与传统理解相反，干净的{001}在产生OH自由基的光氧化反应和析氢的光还原反应中表现出比{101}低的反应性。此外，{010}面显示出最高的光反应性。然而，当用氟部分封端时，这三个面具有相似的光反应性。我们的结论是，表面原子结构（欠配位Ti原子的密度）和表面电子结构（光激发载流子的功率）的合作机制是光反应性的决定因素。这项工作的发现开辟了新的机会，通过光催化剂的形态控制，最大限度地提高光反应性。
Design and morphological control of crystal facets is a commonly employed strategy to optimize the performance of various crystalline catalysts from noble metals to semiconductors.[1–8] The basis of this strategy is that surface atomic configuration and coordination, which inherently determine their heterogeneous reactivity, can be finely tuned by morphological control.[3] The conventional understanding of the surface atomic structure of a crystal is that facets with a higher percentage of undercoordinated atoms are usually more reactive in heterogeneous reactions. For instance,{001} facets of anatase TiO2, which is one of the most important photocatalysts,[9–17] are considered to be more reactive than {101}. We have now discovered, by investigating a set of anatase crystals with predominant {001},{101}, or {010} facets, that, contrary to conventional understanding, clean {001} exhibits lower reactivity than {101} in photooxidation reactions for OH radical generation and photoreduction reactions for hydrogen evolution. Furthermore, the {010} facets showed the highest photoreactivity. However, these three facets had similar photoreactivity when partially terminated with fluorine. We concluded that a cooperative mechanism of surface atomic structure (the density of undercoordinated Ti atoms) and surface electronic structure (the power of photoexcited charge carriers) is the determining factor for photoreactivity. The findings of this work open up new opportunities for maximizing photoreactivity through morphological control of photocatalysts.