Protrudent electron transfer channels on kaolinite modified iron oxide QDs/N vacancy graphitic carbon nitride driving superior catalytic oxidation

Abstract

Optimizing electron transfer channels and sufficiently exposing active sites to trigger an efficient Fenton-like reaction are vital for manipulating catalytic properties of water treatment. Herein, Fe2O3 quantum dots were prepared and integrated with composites of g-C3N4 and kaolinite with nitrogen (N) vacancies (FONGK-10) for bisphenol A (BPA) removal in a peroxymonosulfate (PMS)/visible light (Vis) system. X-ray absorption near-edge structures and extended X-ray absorption fine structures demonstrated interface’s combined properties. In particular, the tight interfacial contact and introduction of N vacancies resulted in the formation of effective electron channels, which caused more effective separation of electron–hole pairs and an extended response time of 1.5 × 10−4 s. Furthermore, the introduction of kaolinite reduced the Fe2O3 particle size and accelerated PMS consumption. The k value in FONGK-10/PMS/Vis system was 4.5 times that of the FONGK-10/PMS and 27.5 times that of the FONGK-10/Vis system, and the synergetic system exhibited superior consecutive catalytic performance in a fluidized-bed catalytic unit, degrading ~100% of BPA in 200 min. The exposed electron channels significantly maintained the Fe(III)/Fe(II) stable dynamic cycle, thereby enhancing the activation of PMS and photocatalysis performance.