Selective micropollutant degradation via nanoconfined core-shell heterostructures with robust resilience to water matrices
Shaoxiong He, Dehai Yu, Chun He, Ping Li, Mengye Wang, Shuanghong Tian, Jingyun Fang
Abstract
The increasing presence of emerging organic micropollutants in water systems poses a significant threat to global water security, yet their selective degradation within complex real water matrices remains a critical challenge. Here, we report the rational design of a TiO2/C2N core-shell photocatalyst that leverages a type II heterostructure-induced built-in electric field to create nanoconfined catalytic sites on the TiO2 surface. The C2N shell selectively allows micropollutants and free chlorine (as an oxidant) to access these catalytic sites while blocking natural organic matter (NOM) via size exclusion and repelling anions through electrostatic interactions, thereby facilitating the selective degradation of micropollutants. The TiO2/C2N heterostructures confine 82.7% of hydroxyl radicals (HO•) near the TiO2 surface, maintaining nearly 100% micropollutant degradation efficiency across varying NOM and anions concentrations, a wide pH range, and real water samples, while unconfined counterparts suffer a 40%–80% reduction in performance. Moreover, precise control of the C2N shell thickness at 5–6 nm optimizes light absorption, oxygen diffusion, and HO• confinement. Additionally, the exclusion of NOM from reaction sites minimizes the formation of toxic disinfection byproducts. This study offers a simple yet viable strategy for developing core-shell photocatalytic heterostructures to selectively degrade target micropollutants in real-world water environments. Authors report a TiO2/C2N core–shell photocatalyst that creates nanoconfined sites for selective micropollutant degradation. The shell blocks natural organics and anions, ensuring high efficiency and resilience in real water environments.