The air-water interface of microbubbles represents a crucial microenvironment that can dramatically accelerate reactive oxidative species (ROS) reactions. However, the dynamic nature of microbubbles presents challenges in probing ROS behaviors at the air-water interface, limiting a comprehensive understanding of their chemistry and application. Here we develop an approach to investigate the interfacial ROS via coupling microbubbles with a Fenton-like reaction. Amphiphilic single-Co-atom catalyst (Co@SCN) is employed to efficiently transport the oxidant peroxymonosulfate (PMS) from the bulk solution to the microbubble interface. This triggers an accelerated generation of interfacial sulfate radicals (SO