Kinetic Engineering of Enzyme@ZIF-L Nanocomposites Enables Water Decontamination with Ultralow Oxidant Consumption.

Abstract

Oxidoreductase enzymes encapsulated in metal-organic frameworks (MOFs) offer an effective approach for water decontamination, yet activity loss during slow coprecipitation severely limits their application. Here, we develop a polyvinylpyrrolidone (PVP)-accelerated strategy that encapsulates horseradish peroxidase (HRP) into a zeolitic imidazolate framework (ZIF-L) within minutes. Time-resolved synchrotron X-ray scattering directly visualizes the nucleation and growth kinetics, revealing that PVP promotes rapid crystallization and drastically shortens enzyme exposure to denaturing conditions. The resulting R-HRP@ZIF-L biocatalytic nanocomposite retains near-native catalytic activity and achieves >99% removal of diverse phenolic micropollutants with an ultralow hydrogen peroxide demand (1.2 equiv relative to the pollutant), while maintaining high efficiency in complex water matrices. Mechanistic investigations reveal a polymerization-dominated pathway that yields separable oligomers rather than mineralization products. This study provides a general synthesis strategy for robust enzyme-MOF biocatalytic nanocomposites, holding strong potential for low-carbon-water decontamination technologies.