 This study proposes a novel approach to enhance the performance of heterogeneous Fenton-like catalysts by confining short-lived reactive species, RS, within carbon nanotubes, CNTs. This nanoconfined catalyst was found to be highly efficient in removing contaminants from water, with the addition of CNTs resulting in increased reaction rates and selectivities compared to conventional Fenton-like catalysts. The nanoconfined catalyst also exhibited superior stability and durability, as well as high resistance to fouling. These findings suggest that this nanoconfined catalyst could serve as a promising solution for water purification applications. This article was authored by Tone Sileu, Shazer Xiao, Nan Li, and others.