Unique phase transformation behavior and visible light photocatalytic activity of titanium oxide hybridized with copper oxide
Unique phase transformation behavior and visible light photocatalytic activity of titanium oxide hybridized with copper oxide
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DOI：
10.1039/b922510b
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发表时间：
2010-01-01
影响因子：
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通讯作者：
Hwang, Seong-Ju
中科院分区：
文献类型：
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作者：
Kim, Tae Woo;Ha, Hyung-Wook;Hwang, Seong-Ju
通过氧化钛与氧化铜的纳米级杂化来控制氧化钛的相变行为，开发出一种在可见光下具有活性的新型光催化剂。通过X射线衍射、电子显微镜和氮气吸附-脱附等温线测量孔径分布的分析表明，氧化铜和氧化钛之间的插层杂化产生了介孔层间异质结构，其重复距离约为24.2埃，平均孔径约为52埃。 Cu K-和Ti K-边缘的X射线吸收光谱清楚地表明二价铜氧化物与纤铁矿型氧化钛间层化。由于能带结构的改变，所得纳米杂化物在可见光照射下对有机染料分子的光诱导降解表现出高活性。在 500 摄氏度下对纳米杂化物进行热处理，生成了锐钛矿型 TiO2，但牺牲了在较低温度区域（300-400 摄氏度）形成的中间金红石型 TiO2。这表明从金红石型 TiO2 到锐钛矿型 TiO2 的相变。这种现象与杂化氧化铜的氧化还原过程和共存的缺钛氧化钛的相变引起的二氧化钛表面能的变化有关。
The nanoscale hybridization of titanium oxide with copper oxide was carried out to control the phase transformation behavior of titanium oxide and develop a new photocatalyst active in visble light. Analysis by X-ray diffraction, electron microscopy, and nitrogen adsorption-desorption isotherm to gauge pore size distribution showed that intercalative hybridization between copper oxide and titanium oxide produced a mesoporous layer-by-layer interstratified heterostructure with a repeating distance of similar to 24.2 angstrom and an average pore size of similar to 52 angstrom. X-ray absorption spectroscopy at Cu K- and Ti K-edges clearly demonstrated that divalent copper oxides were interstratified with lepidocrocite-type titanium oxide. As a result of the modification of band structure, the resulting nanohybrids showed high activity for photoinduced degradation of organic dye molecules under visible light illumination. Heat-treatment of the nanohybrids at 500 degrees C produced anatase TiO2 at the expense of intermediate rutile TiO2 formed in the lower temperature region (300-400 degrees C). This suggests a phase transition from rutile TiO2 to anatase TiO2. This phenomenon is related to the variation in the surface energy of titania caused by the redox process of hybridized copper oxide and by the phase transition of co-existing Ti-deficient titanium oxide.