Developing a g-C3N4/NiFe2O4 S-scheme hetero-assembly for efficient photocatalytic degradation of cephalexin

Abstract

The step-scheme (S-scheme) heterojunctions with superior redox capability have recently emerged as one of the most promising materials for cleaning up of contaminated environments. Herein, we synthesized g-C3N4/NiFe2O4 (NFC) heterojunction photocatalyst via a hydrothermal route for the degradation of Cephalexin (CPX). The integration of g-C3N4 and NiFe2O4 into heterojunction with an effective S-scheme transfer which prevents the recombination of essential photoexcited electron-hole pairs leads to excellent 99.3% of photocatalytic degradation of CPX within 60 min under visible light. The scavenging experiments suggested •OH and •O2- radicals generated on high potential bands of S-Scheme g-C3N4/NiFe2O4 as active species responsible for high performance CPX removal. The degradation intermediates were examined by Liquid Chromatography mass spectroscopy (LC-MS) and a probable pathway of CPX degradation was proposed accordingly. The inherent work function between g-C3N4 and NiFe2O4 leads to bending of conduction and valence bands which subsequently forms an built-in electric field across the interface facilitating the superior separation of photogenerated electrons and holes. The five subsequent recycling tests demonstrated the catalyst’s strong photocatalytic stability and the easy recovery process because of its magnetic characteristic. This research may bring fresh insights for constructing magnetic photocatalysts based on g-C3N4, which are both highly effective and stable. Additionally, it also paves a path for the designing of S-scheme heterojunctions with great performance for environmental remediation applications.