The urgent quest to introduce the Xenes, a new family of graphene‐like materials, into everyday technological devices further demands for a specific understanding of their reactivity to different environments. Here, the role of oxygen on the blue phosphorene fragments alloyed with Au(111) substrate, so called BlueP‐Au alloy, is investigated either on a microscopic scale or at the interface with Al2O3, commonly used to protect Xenes in ambient conditions. Although molecular oxygen does not affect the BlueP‐Au alloy nor intercalate below it, the role of oxygen is fundamental to relief the charging effects at the very interface between Al2O3 and BlueP‐Au alloy when exposed to air. These findings highlight the importance of combining different tools, including microscopy and spectroscopy, to ascertain the stability of two‐dimensional materials in device‐ready configurations.This article is protected by copyright. All …