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利用 X射线光电子能谱 (XPS)、X射线衍射 (XRD)及扩展的 X射线精细结构谱 (EXAFS)对氧化钴在二氧化钛表面的分散及结构进行了系统研究。结果表明 :氧化钴能够在二氧化钛表面实现单层分散 ,其分散阈值为每平方纳米的二氧化钛分布 1.4个钴原子。当负载量小于分散阈值时 ,钴以二价存在并形成分立的钴氧六配位 [Co O6];而当负载量大于分散阈值时 ,晶体 Co3 O4在二氧化钛表面形成 ,钴以两种形式存在 ,即分散态的钴氧六配位 [Co O6]和晶态的 Co3 O4。实验还表明二氧化钛对二价钴具有明显的稳定作用
The dispersion and structure of cobalt oxide on titania surface were studied systematically by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and extended X-ray diffraction (EXAFS) The results show that cobalt oxide can be monolayer dispersed on the surface of titanium dioxide with the distribution threshold of 1.4 cobalt atoms per square nanometer of titanium dioxide. When the loading is less than the dispersion threshold, cobalt exists at two valences and forms discrete cobaltoxalate [CoO6]; when the loading is greater than the dispersion threshold, the crystalline Co3 O4 is formed on the surface of titania and the cobalt exists in two forms , That is, dispersed cobalt hexacoordinated [CoO6] and crystalline Co3O4. Experiments also show that titanium dioxide has a significant stabilizing effect on the divalent cobalt