School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, Fife, UK.
J Phys Condens Matter. 2011 Jun 15;23(23):234111. doi: 10.1088/0953-8984/23/23/234111. Epub 2011 May 25.
The proton conducting material Ba(3)Ca(1.18)Ta(1.82)O(8.73) (BCT18) was synthesized and characterized using diffraction methods and thermal analysis. It was shown that BCT18 is structurally similar to its niobium analogue (BCN18). At synthesis temperatures up to 1500 °C however, BCT18 forms a mixture of Ca- and Ta-site ordered phases, with both 1:1 type and 1:2 type ordering. The phase ratio seems to depend solely on the synthesis conditions, with 1:1 type ordering being the dominant form in most cases. Thermal treatment in vacuum, wet and dry hydrogen, and CO(2) suggests that both forms contain defects (Ca(Ta)(''') and V(O)(··)), allowing the material to absorb water and CO(2). The uptake and the release of H(2)O and of CO(2) are all reversible, as evidenced by x-ray diffraction studies and thermal analysis, suggesting that the molecules are present as structural defects (OH(O)(·) and CO(3O)(×)), rather than surface species or separate hydroxide or carbonate phases. Solid state (1)H nuclear magnetic resonance also confirms the presence of protons, and the peak broadening suggests that they are mobile at room temperature.
质子导体材料 Ba(3)Ca(1.18)Ta(1.82)O(8.73)（BCT18）通过衍射方法和热分析进行了合成和表征。结果表明，BCT18 的结构与其铌类似物（BCN18）相似。然而，在合成温度高达 1500°C 时，BCT18 形成了钙和钽位有序相的混合物，具有 1:1 型和 1:2 型两种有序方式。相比例似乎仅取决于合成条件，在大多数情况下，1:1 型有序是主要形式。在真空中、湿氢气和干氢气以及 CO(2)中的热处理表明，这两种形式都含有缺陷（Ca(Ta)(''') 和 V(O)(··)），允许材料吸收水和 CO(2)。X 射线衍射研究和热分析表明，H(2)O 和 CO(2)的吸收和释放都是可逆的，这表明分子以结构缺陷（OH(O)(·) 和 CO(3O)(×)）的形式存在，而不是表面物种或单独的氢氧化物或碳酸盐相。固态（1）H 核磁共振也证实了质子的存在，峰展宽表明它们在室温下是可移动的。
