Basicity and Solubility of Water in Solid Complex Oxides

根据固体复合氧化物中局部酸碱中心的部分酸/碱反应，考察和讨论了水在各种固体复合氧化物中的溶解度。将水溶解反应定义为如下部分酸/碱反应的总体反应：[数值形式]缺陷或掺杂阳离子附近的正常位上的氧空位和正常氧离子被定义为酸位和碱位，它们分别是反应(1)和(2)的有利位。使用主体氧化物的电子能带结构来定义各个中心的碱性或酸性的强度；酸中心和碱中心对应于主体氧化物的LUMO和HOMO水平，并作为部分反应(1)和(2)的结果形成受体和质子诱导水平。为了验证上述概念，用二次离子质谱仪(SIMS)、光电子能谱和软X射线吸收/发射光谱测量了掺入不同三价稀土离子的CeO_2单晶的溶解度，以比较水在掺杂的ZrO_2中的相对较低的溶解度。还考察了用perovskitestructuredopedwithacceptordopantstoB-site.测量钛酸盐、锆酸盐和金属陶瓷的溶解度和电子能谱实验结果证实了所提出的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.