Harnessing air-water interface to generate interfacial ROS for ultrafast environmental remediation.

Xie, Ruijie; Guo, Kaiheng; Li, Yong; Zhang, Yingguang; Zhong, Huanran; Leung, Dennis Y C; Huang, Haibao · Nat Commun · 2024

basic_science · Level V

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Abstract

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<sub>4</sub><sup>•-</sup>), with 20-fold higher concentration (4.48 × 10<sup>-11</sup> M) than the bulk SO<sub>4</sub><sup>•-</sup>. Notably, the generated SO<sub>4</sub><sup>•-</sup> is preferentially situated at the air-water interface due to its lowest free energy and the strong hydrogen bonding interactions with H<sub>3</sub>O<sup>+</sup>. Moreover, it exhibits the highest oxidation reactivity toward gaseous pollutants like toluene, with a rate constant of 10<sup>10 </sup>M<sup>-1</sup> s<sup>-1</sup>-over 100 times greater than bulk reactions. This work demonstrates a promising strategy to harness the air-water interface for accelerating ROS-induced reactions, highlighting the importance of interfacial ROS and its potential application.