Facile Synthesis under Near-Atmospheric Conditions and Physicochemical Properties of Hairy CeO2 Nanocrystallines
Facile Synthesis under Near-Atmospheric Conditions and Physicochemical Properties of Hairy CeO2 Nanocrystallines
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DOI：
10.1021/jp809703h
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发表时间：
2009-01
影响因子：
3.7
通讯作者：
Xiaodong Li;Ji-guang Li;D. Huo;Z. Xiu;Xudong Sun
中科院分区：
文献类型：
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作者：
Xiaodong Li;Ji-guang Li;D. Huo;Z. Xiu;Xudong Sun
在常温下用过氧化氢(H_2O_2)处理新鲜制备的氢氧化铈，为将纳米CeO_2(∼22 nm，37m~2/g)转化为直径细小(最小可达∼5 nm)、比表面积高(∼为184m~2/g)的纳米线提供了一种简便有效的方法。用X射线衍射仪、比表面积法、傅立叶变换红外光谱、热重、高分辨透射电子显微镜、拉曼光谱和UV-−-Vis吸收光谱对CeO2纳米材料进行了表征。结果表明，纳米线为单晶，纯度高，缺陷(氧空位)浓度低，且垂直于{220}晶面生长。CeO2纳米线的间接带隙和直接带隙分别为∼2.37 eV和2.91 eV，分别比纳米粒子形式的带隙(∼22 nm)低0.15 eV。以不稳定的Ce(OH)3O·OH过氧化中间体为模板，通过溶解−再沉淀机制生长了CeO2纳米线。
Treating freshly prepared cerous hydroxide with hydrogen peroxide (H2O2) under ambient conditions provides a facile and efficient way for converting CeO2 nanoparticles (∼22 nm, 37 m2/g) into nanowires of fine diameters (down to ∼5 nm) and outstanding specific surface areas (∼184 m2/g). The CeO2 nanomaterials were examined by XRD, BET, FT-IR, TG, HR-TEM, Raman scattering, and UV−vis absorption spectroscopy. The results show that the nanowires are single crystalline and of high purity and low defect (oxygen vacancy) concentration and are growing perpendicular to {220} planes. The CeO2 nanowires show indirect and direct band gaps of ∼2.37 and 2.91 eV, respectively, which are both ∼0.15 eV lower than those observed from the nanoparticle form (∼22 nm) for the respective interband transitions. The CeO2 nanowires were proposed to grow via a dissolution−reprecipitation mechanism, with an unstable Ce(OH)3O·OH hyperoxide intermediate as the template.