Institute of Physical Chemistry, RWTH Aachen University, Germany.
Phys Chem Chem Phys. 2013 Dec 7;15(45):19825-30. doi: 10.1039/c3cp53039f. Epub 2013 Oct 21.
We report nuclear magnetic resonance (NMR) results on water saturated, dense, nano-crystalline YSZ samples (9.5 mol% yttria doped zirconia) which exhibit proton conductivity at temperatures as low as room temperature. (1)H-NMR spectra recorded under static and magic angle spinning conditions show two distinct signals. Their temperature-dependent behavior and their linewidths suggest that one can be attributed to (free) water adsorbed on the surface of the sample and the other one to mobile protons within the sample. This interpretation is supported by comparison with measurements on a single-crystalline sample. For the nano-crystalline samples motional narrowing is observed for the signal originating from protons in the sample interior. For these protons, the analysis of temperature and field dependent spin-lattice relaxation time T1 points towards diffusion in a confined two-dimensional geometry. We attribute this quasi two-dimensional motion to protons that are mobile along internal interfaces or nanopores of nano-crystalline YSZ.
我们报告了水饱和、致密、纳米晶 YSZ 样品（9.5 摩尔%氧化钇掺杂氧化锆）的核磁共振（NMR）结果，这些样品在低至室温的温度下表现出质子导电性。在静态和魔角旋转条件下记录的 (1)H-NMR 光谱显示出两个不同的信号。它们的温度依赖性及其线宽表明，一个信号可以归因于（游离）吸附在样品表面的水，另一个信号归因于样品内部的移动质子。这种解释得到了与单晶样品测量结果的比较的支持。对于纳米晶样品，观察到起源于样品内部质子的信号的运动变窄。对于这些质子，对温度和场依赖的自旋晶格弛豫时间 T1 的分析表明在受限的二维几何结构中扩散。我们将这种准二维运动归因于沿纳米晶 YSZ 的内部界面或纳米孔移动的质子。
