Two dimensional Co3O4/g-C3N4 Z-scheme heterojunction: Mechanism insight into enhanced peroxymonosulfate-mediated visible light photocatalytic performance

Abstract

In this study, to improve peroxymonosulfate (PMS)-mediated visible-light photocatalytic performance of g-C3N4 in antibiotics degradation and elucidate its mechanism, an ultrathin Co3O4 nanomeshes/g-C3N4 nanosheets 2D Z-scheme heterojunction composite (x% Co3O4/g-C3N4) was successfully prepared calcining the mixtures of MOF-Co ultrathin nanosheets and g-C3N4. This unique nanomeshes/nanosheets structure with large SSA (153.92 m2/g) possessed an abundance of accessible active sites and large area intimate interfaces between Co3O4 and g-C3N4, thus remarkably promoting the separation and transport of charge carriers. The as-prepared optimal 10% Co3O4/g-C3N4 composites exhibited excellent degradation efficiency toward tetracycline (TC) under visible light irradiation and were further enhanced with the addition of PMS. The mechanism of the enhanced TC degradation in Co3O4/g-C3N4/Vis/PMS system was investigated in detail based on the characterization of the catalysts, TC degradation efficiency assessment, electron paramagnetic resonance (EPR) measurements, and reactive oxygen species (ROSs) quenching results. The TC degradation pathway was proposed based on the intermediates identified by the gas chromatography-mass spectrometer (GC–MS) measurements. This study provides a facile and promising path for the remediation of contaminated water via PMS mediated photocatalysis over highly active g-C3N4-based catalysts.