Nanostructured ZIF-67/LaFeO3 p–n heterojunction interface for amplified cefotaxime sensing & intensified photo-Fenton degradation

Abstract

The efficient removal and detection of antibiotic contaminants without generating hazardous byproducts remain critical challenges in environmental chemistry. Herein, a ZIF-67/LaFeO₃ nanocomposite with a high specific surface area (1082.94 m² g⁻¹) is constructed to function as a dual mode photocatalyst and electrochemical sensor for cefotaxime (CFX). Benefiting from a synergistic type-II p–n heterojunction, the composite exhibits rapid visible light driven photocatalytic degradation of CFX in the presence of hydrogen peroxide (H₂O₂), achieving 90.1% removal within 10 min with an apparent rate constant (K_app) of 0.1014 min⁻¹, markedly outperforming pristine ZIF-67 and LaFeO₃. When integrated onto a screen-printed carbon electrode, the ZIF-67/LaFeO₃ electrode demonstrates sensitive electrochemical detection of CFX with a limit of detection of 3.41 ppm and a limit of quantification of 10.1 ppm at pH 6 and 40 ppm cefotaxime (CFX) concentration. Electrochemical impedance spectroscopy (EIS) reveals enhanced charge separation efficiency and reduced interfacial charge transfer resistance upon LaFeO₃ integration. Degradation intermediates and plausible reaction pathways are identified by high-resolution mass spectroscopy (HR-MS). This study demonstrates the rational design of a heterostructure MOF-based system for integrated antibiotic sensing and wastewater remediation.