Nanoconfined core-shell heterogeneous fenton reactor: Accelerated degradation of organic pollutants in flow-through systems

Integrating heterogeneous catalysts into porous matrices as flow-through reactors has attracted significant attention for continuous elimination of dissolved organic contaminants. However, the catalytic activity of most flow-through reactors is severely limited by the short diffusion length of generated reactive species. Inspired by the natural biological systems that achieve remarkable rate acceleration within nanoconfined environments, we designed an ultra-fast flow-through catalytic reactor featuring nanoconfined reaction environment by incorporating engineered core–shell iron-based heterogeneous catalysts (C-MIC). The porous silica shell of C-MIC facilitates catalytic reactions in a confined environment, enhancing activity through local concentration and nanoconfinement effects. Meanwhile, the polydopamine (PDA) matrix of C-MIC promotes efficient electron transfer and preserves the structural integrity of the catalysts, accelerating the catalytic rate up to 0.505 min−1 for model dyes. Moreover, the C-MIC based composite reactor achieved a flow rate up to ∼2000 L m−2 h−1 for continuous flow-through degradation of organic dyes, antibiotics, and endocrine-disrupting compounds, and maintaining its catalytic efficiency across a wide pH range and after multiple cycles, and this performance surpasses most reported flow-through reactor. This work provides a new strategy for designing advanced oxidation process (AOP) catalyst with regulated nanoconfined structures to achieve superior catalytic performance for various environmental engineering applications. © 2024 The Author(s)