Morphology-function relationship of ZnO: Polar planes, oxygen vacancies, and activity
Morphology-function relationship of ZnO: Polar planes, oxygen vacancies, and activity
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DOI：
10.1021/jp8038626
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发表时间：
2008-08-07
影响因子：
3.7
通讯作者：
Zhu, H. Y.
中科院分区：
文献类型：
--
作者：
Li, G. R.;Hu, T.;Zhu, H. Y.
通过对ZnO的极性面、氧空位和催化剂活性的研究，揭示了ZnO的形貌与功能之间的关系。通过简单的水热反应可控地合成了各种形貌的ZnO。扫描电子显微镜图像显示出各种各样的六方氧化锌：棒，盘，环，螺旋帽作为ZnO形态家族的新成员。每种形貌在ZnO晶体外表面的（0001）和（0001）极性面的比例上与其它形貌显著不同。光致发光谱分析表明，在极性面较大的样品中存在较多的氧空位。合成的样品被用作催化剂的苯胺的N-取代，并显示出一个形态依赖的活性：ZnO与大极性平面是更催化活性的N-取代反应。这是由于极性面容易产生氧空位，而氧空位被认为是催化N-取代反应的有利位点。结果表明，极性面，氧空位，和催化活性之间的正相关性为N-取代。
The relationship between morphology and function of ZnO is demonstrated by investigating its polar planes, oxygen vacancies, and catalytic activity for N-formylation. ZnO with various morphologies is controllably synthesized via simple hydrothermal reactions. Scanning electron microcopy images exhibit a variety of the as-prepared hexagonal zinc oxides: rods, disks, rings, and screw caps as a new member of ZnO morphology family. Each of the morphologies is remarkably different from the others in the proportion of the (0001) and (0001) polar planes in the outside surfaces of ZnO crystals. The analysis of photoluminescence spectra shows that there exist more oxygen vacancies in the samples with large polar planes. The synthesized samples are used as a catalyst for the N-formylation of aniline and show a morphology-dependent activity: ZnO with large polar planes is more catalytically active for the N-formylation reaction. This is attributed to the fact that the polar planes generate easily oxygen vacancies, which are considered as the favored sites for catalyzing the N-formylation reaction. The results suggest a positive relationship among polar planes, oxygen vacancies, and catalytic activity for N-formylation.