Sm-doped CeO2-δ (Ce0.9Sm0.1O2-δ; SDC) thin films were prepared on Al2O3 (0001) substrates by radio frequency magnetron sputtering. The prepared thin films were preferentially grown along the [111] direction, with the spacing of the (111) plane (d111) expanded by 2.6% to compensate for a lattice mismatch against the substrate. The wet-annealed SDC thin film, with the reduced d111 value, exhibited surface protonic conduction in the low-temperature region below 100 °C. The O1s photoemission spectrum exhibits H2O and OH- peaks on the SDC surface. These results indicate the presence of physisorbed water layers and the generation of protons on the SDC (111) surface with oxygen vacancies. The protons generated on the SDC surface were conducted through a physisorbed water layer by the Grotthuss mechanism.

中文翻译：

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在Al2O3上优先生长的Sm掺杂CeO2-δ薄膜的表面质子传导（0001）。

通过射频磁控溅射在Al2O3（0001）基片上制备了掺Sm的CeO2-δ（Ce0.9Sm0.1O2-δ; SDC）薄膜。所制备的薄膜优选沿[111]方向生长，（111）平面（d111）的间距扩大了2.6％，以补偿与基板的晶格失配。d111值降低的湿退火SDC薄膜在低于100°C的低温区域表现出表面质子传导。O1s的光发射光谱在SDC表面上显示H2O和OH-峰。这些结果表明存在物理吸附的水层，并且在具有氧空位的SDC（111）表面上产生了质子。通过Grotthuss机理将SDC表面产生的质子穿过物理吸附的水层。