Missaoui Ghada, Wemhoff Piotr Igor, Nilius Niklas
Carl von Ossietzky University Oldenburg, Institute of Physics, D-26111, Oldenburg, Germany.
Chemphyschem. 2024 Jul 2;25(13):e202300988. doi: 10.1002/cphc.202300988. Epub 2024 May 2.
Monolayer vanadium oxide films grown on Pt(111) can be reversibly switched between an oxygen-poor and an oxygen-rich composition, equivalent to VO and VO, respectively. While the overall oxygen storage capacity of the film is quantified by X-ray photoelectron spectroscopy, the atomic binding sites of the extra O species are determined by low-temperature scanning tunneling microscopy and electron diffraction. In the O-poor phase, the oxide takes the form of a honeycomb lattice that gets partially covered with vanadyl (V=O) groups at higher O exposure. Upon transition to the O-rich phase, isolated VO rings emerge in the film first, which then evolves towards a disordered O-V-O trilayer on the Pt(111) surface. Our works thus unravels the microscopic nature of reversible oxygen storage in a model system for heterogeneous catalysis.
生长在Pt(111)上的单层氧化钒薄膜可以在贫氧和富氧组成之间可逆切换，分别相当于VO和VO₂。虽然薄膜的整体储氧能力通过X射线光电子能谱进行量化，但额外O物种的原子结合位点由低温扫描隧道显微镜和电子衍射确定。在贫氧相中，氧化物呈蜂窝晶格形式，在较高的O暴露量下会部分被氧钒（V=O）基团覆盖。在向富氧相转变时，薄膜中首先出现孤立的VO₂环，然后在Pt(111)表面演变成无序的O-V-O三层结构。因此，我们的工作揭示了多相催化模型系统中可逆储氧的微观本质。
