Hussain H, Torrelles X, Rajput P, Nicotra M, Thornton G, Zegenhagen J
London Centre for Nanotechnology and Department of Chemistry, University College London , 20 Gordon Street, London WC1H OAJ, United Kingdom ; ESRF , 6 rue Jules Horowitz, F-38000 Grenoble cedex, France.
Institut de Ciència de Materials de Barcelona (CSIC) , Campus UAB, 08193 Bellaterra, Spain.
J Phys Chem C Nanomater Interfaces. 2014 May 22;118(20):10980-10988. doi: 10.1021/jp5034118. Epub 2014 Apr 23.
Surface X-ray diffraction has been employed to elucidate the structure of the interface between a well-characterized (001) surface of 0.1 wt % Nb-SrTiO and liquid HO. Results are reported for the clean surface, the surface in contact with a drop of liquid water, and the surface after the water droplet has been removed with a flow of nitrogen. The investigation revealed that the clean surface, prepared via annealing in 1 × 10 mbar O partial pressure, is unreconstructed and rough on a short length scale. The surface is covered with large terraces, the topmost layer of which is either TiO or SrO with an area ratio of about 7/3. For the surface in contact with water, our results reveal that associative HO adsorption is favored for the TiO-terminated terrace whereas adsorption is dissociative for the SrO-terminated terrace, which validates recent first-principles calculations. After removal of the water droplet, the surface largely resembles the water-covered surface but now with a disordered overlayer of water present on the surface.
表面X射线衍射已被用于阐明0.1 wt% Nb-SrTiO的特征良好的(001)表面与液态H₂O之间的界面结构。报告了清洁表面、与一滴水接触的表面以及用水滴去除后用氮气流处理的表面的结果。研究表明，通过在1×10⁻⁶ mbar O₂分压下退火制备的清洁表面未发生重构，且在短长度尺度上是粗糙的。表面覆盖着大平台，其最顶层要么是TiO₂要么是SrO，面积比约为7/3。对于与水接触的表面，我们的结果表明，缔合的H₂O吸附有利于TiO₂终止的平台，而对于SrO终止的平台吸附是解离的，这验证了最近的第一性原理计算。去除水滴后，表面在很大程度上类似于被水覆盖的表面，但现在表面存在无序的水覆盖层。
