Basicity and Solubility of Water in Solid Complex Oxides

本文根据固体复合氧化物中局部酸碱位上的部分酸碱反应，对水在固体复合氧化物中的溶解度进行了研究和讨论。水溶解反应被定义为以下部分酸/碱反应的总体反应：[数值公式]将在缺陷或掺杂剂阳离子附近的正常位点上的氧空位和正常氧离子在相似位点中具有最高强度定义为酸性位点和碱性位点，它们分别是反应（1）和（2）的有利位点。使用主体氧化物的电子能带结构来定义各个位点的碱性或酸性的强度;酸位点和碱位点对应于主体氧化物的LUMO和HOMO能级，并且作为部分反应（1）和（2）的结果形成受体和质子诱导能级。为了验证这一概念，我们用二次离子质谱（西姆斯）、光电子能谱（XPS）和软X射线吸收/发射光谱（SFT）对掺杂不同三价稀土离子的CeO_2单晶进行了溶解度的测量，比较了水在掺杂ZrO_2中较低的溶解度。还研究了钛酸盐，锆酸盐，和cerates与钙钛矿结构opedwith受体dopantstoB-网站的水溶性和电子光谱测量。实验结果验证了部分酸碱反应模型的正确性。

The Solubility of water in various solid complex oxides has been examined and discussed based on the partial acid/base reactions on the local acid and base sites in the oxides. The water dissolution reaction is defined as a overall reaction of the partial acid/base reactions below:【numerical formura】Oxygen vacancies and normal oxide ions on the normal site in the vicinity of defects or dopant cations with the highest intensity among similar sites are defined as acid site and basic site, which are favorable sites for the reactions (1) and (2), respectively. The intensity of basicity or acidity of respective sites are defined using the electronic band structure of host oxides; acid site and base site correspond to LUMO and HOMO levels of host oxides and form acceptor and proton induced levels as results of the partial reactions (1) and (2). In order to examine the concept above, both the solubility measurements on single crystals of CeO_2 doped with various kind of trivalent lanthanide ions using Secondary Ion Mass Spectrometiy (SIMS) and Photo Electron Spectroscopy and Soft X-ray Absorption/Emission Spectroscopy measurements, to compare the relatively low solubility of water in doped ZrO_2. Also examined were both the water solubility and electron spectroscopy measurements on titanates, zirconates, and cerateswith perovskitestructuredopedwithacceptordopantstoB-site. Fromtheseexperimental results, the validity of proposed partial acid/base reaction model was confirmed.