The reconstruction of rutile TiO₂ (110) holds significant importance as it profoundly influences the surface chemistry and catalytic properties of this widely used material in various applications, from photocatalysis to solar energy conversion. Here, we directly observe the asymmetric surface reconstruction of rutile TiO₂ (110)-(1×2) with atomic-resolution using in situ spherical aberration-corrected scanning transmission electron microscopy. Density functional theory calculations were employed to complement the experimental observations. Our findings highlight the pivotal role played by repulsive electrostatic interaction among the small polarons −formed by excess electrons following the removal of neutral oxygen atoms− and the subsequent surface relaxations induced by these polarons. The emergence and disappearance of these asymmetric structures can be controlled by adjusting the oxygen partial pressure. This research provides a deeper understanding, prediction, and manipulation of the surface reconstructions of rutile TiO₂ (110), holding implications for a diverse range of applications and technological advancements involving rutile-based materials.

金红石TiO ₂ (110) 的重构具有重要意义，因为它深刻地影响了这种广泛使用的材料在从光催化到太阳能转换等各种应用中的表面化学和催化性能。在这里，我们使用原位球差校正扫描透射电子显微镜以原子分辨率直接观察金红石TiO ₂ (110)-(1×2)的不对称表面重建。采用密度泛函理论计算来补充实验观察结果。我们的研究结果强调了小极化子（中性氧原子去除后多余电子形成）之间的排斥静电相互作用以及这些极化子引起的后续表面弛豫所发挥的关键作用。这些不对称结构的出现和消失可以通过调节氧分压来控制。这项研究提供了对金红石 TiO ₂ (110) 表面重建的更深入的理解、预测和操纵，对涉及金红石基材料的各种应用和技术进步具有重要意义。