# Nanoconfinement‐Steered Molecular Preorganization Enables Efficient Monoethanolamine Degradation through Electronically Modulated High‐Valent Iron–Oxo Pathways

## TL;DR

A new method uses nanoconfinement to control chemical reactions, making monoethanolamine degradation more efficient and selective.

## Contribution

A synergistic proton–electron transfer mechanism is revealed through spatial preorganization in engineered nanoconfinement.

## Key findings

- Nanoconfinement redirects MEA degradation to a high-valent iron–oxo pathway.
- Spatial constraints enable regioselective C–N bond cleavage via electrophilic attack.
- Interfacial synergy enhances degradation kinetics by 4.85-fold.

## Abstract

While nanoconfinement effectively stabilizes ultrasmall metal nanoparticles to enhance peroxymonosulfate (PMS) activation in Fenton‐like systems, precise control over reaction pathways remains challenging. To address this, ultrasmall UiO‐66─ZrFe nanoparticles within a π‐electron‐enriched asymmetric graphene aerogel (GA) are immobilized. This designed confinement architecture not only redirects PMS‐activated monoethanolamine (MEA) degradation from nonselective radical oxidation to a dominant high‐valent iron–oxo (Fe(IV)═O) pathway but, more importantly, enables a synergistic mechanism coupling molecular preorganization with proton–electron coregulation. Specifically, spatial constraints within UiO‐66─ZrFe cages enable MEA to orient its amino group (─NH2) toward Fe(IV)═O species. This configuration promotes electrophilic attack by Fe(IV)═O on the lone‐pair electrons in ─NH2, simultaneously triggering intramolecular C─N bond cleavage with concomitant proton release. Liberated protons are electrostatically stabilized on the π‐conjugated GA network, establishing synergistic coupling with Fe─PMS coordination. This interfacial synergy facilitates directional electron transfer from Fe sites to the carbon matrix and results in regioselective catalysis, enhancing MEA degradation kinetics by 4.85‐fold. Practical viability for wastewater remediation is confirmed through life cycle assessment and extended operation. This strategy establishes a generalized design principle for precise reaction control via the orchestration of coupled spatial and electronic effects within engineered microenvironments.

Precise modulation of reaction pathways remains an unresolved challenge in peroxymonosulfate‐activated advanced oxidation processes. The spatial preorganization strategy in engineered confinement architecture enables regioselective bond cleavage in monoethanolamine via synergistic proton–electron transfer, redirecting its degradation from nonselective radicals toward a dominant high‐valent iron–oxo pathway and thereby establishing programmable microenvironments for precision catalysis.