Interaction of molecular oxygen with semiconducting oxide surfaces plays a key role in many technologies. The topic is difficult to approach both by experiment and in theory, mainly due to multiple stable charge states, adsorption configurations, and reaction channels of adsorbed oxygen species. Here we use a combination of noncontact atomic force microscopy (AFM) and density functional theory (DFT) to resolve O2 adsorption on the rutile TiO2(110) surface, which presents a longstanding challenge in the surface chemistry of metal oxides. We show that chemically inert AFM tips terminated by an oxygen adatom provide excellent resolution of both the adsorbed species and the oxygen sublattice of the substrate. Adsorbed O2 molecules can accept either one or two electron polarons from the surface, forming superoxo or peroxo species. The peroxo state is energetically preferred under any conditions relevant for applications. The possibility of nonintrusive imaging allows us to explain behavior related to electron/hole injection from the tip, interaction with UV light, and the effect of thermal annealing.

分子氧与半导体氧化物表面的相互作用在许多技术中发挥着关键作用。该主题在实验和理论上都很难解决，主要是由于吸附氧物质的多个稳定电荷态、吸附构型和反应通道。在这里，我们结合使用非接触原子力显微镜（AFM）和密度泛函理论（DFT）来解决氧2金红石上的吸附时间我氧2（110）表面，这对金属氧化物的表面化学提出了长期的挑战。我们表明，由氧吸附原子终止的化学惰性 AFM 尖端可为吸附物质和基底的氧亚晶格提供出色的分辨率。吸附氧2分子可以接受来自表面的一个或两个电子极化子，形成超氧或过氧物种。在任何与应用相关的条件下，过氧态都是积极优选的。非侵入式成像的可能性使我们能够解释与从尖端注入电子/空穴、与紫外光相互作用以及热退火效应相关的行为。