Carbonate radicals mediated catalytic degradation of antibiotics over earth-abundant BaCO3-based system: Performance, mechanism and calculation

Abstract

The semiconductor-insulator heterostructure, characterized by outstanding economic-efficiency and catalytic activity, represents a promising photocatalyst for practical pollutants degradation. However, achieving energy band matching between semiconductors and insulators remains a challenge. In this study, we meticulously designed and synthesized a band-matched semiconductor-insulator photocatalysts (AgI-BaCO3), leveraging the in-situ nucleation of ultrafine AgI nanoparticles on BaCO3 surface. The finely crafted heterostructure notably enhanced degradation efficiency of tetracycline over both pure AgI and BaCO3, demonstrating a remarkable pseudo-first-order kinetic rate constant that surpassed them by 27.2 and 33.5 times, respectively. The density functional theory calculations uncovered that the intense covalent interaction between AgI and BaCO3 established a specific channel for interfacial charge carriers. The generated CO3·- radicals as the main active species markedly expedited the removal of antibiotics. Furthermore, the catalysts demonstrated robust activity in real wastewater and surface water. This work supplies a novel reference for constructing insulator-based photocatalysts and elucidates its potential application in actual aquatic environments.