<i>In Situ</i> Resolving the Atomic Reconstruction of SnO<sub>2</sub> (110) Surface.

Li, Guanxing; Li, Songda; Han, Zhong-Kang; Zou, Chen; Wu, Hanglong; Yuan, Wentao; Zhu, Beien; Gao, Yi et al. · Nano Lett · 2021

basic_science · Level V

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Abstract

Understanding surface reconstruction of nanocrystals is of great importance to their applications, however it is still challenging due to lack of atomic-level structural information under reconstruction conditions. Herein, through <i>in situ</i> spherical aberration corrected scanning transmission electron microscopy (STEM), the reconstruction of nanocrystalline SnO<sub>2</sub> (110) surface was studied. By identifying the precise arrangements of surface/subsurface Sn and O columns through both <i>in situ</i> bright-field and high-angle annular dark-field STEM images, an unexpected added Sn<sub>2</sub>O model was determined for SnO<sub>2</sub> (110)-(1 × 2) surface. The protruded Sn<sup>δ+</sup> of this surface could act as the active sites for activating O<sub>2</sub> molecules according to our density functional theory (DFT) calculations. On the basis of <i>in situ</i> observation of atomic-level reconstruction behaviors and DFT calculations, an energy-driven reconstruction process was also revealed. We anticipate this work would help to clarify the long-standing debate regarding the reconstruction of SnO<sub>2</sub> (110) surface and its intrinsic property.