Construction of g-C3N4/BiOCl/CdS heterostructure photocatalyst for complete removal of oxytetracycline antibiotic in wastewater

One of the vital topics in photocatalysis research is the development of novel photocatalytic nanomaterials for degradation of toxic pollutants in the natural water under visible light irradiation. Herein we report, for the first time, a facile hydrothermal synthesis of g-C3N4/BiOCl/CdS heterojunction for complete removal of oxytetra-cycline (OTC) antibiotic in wastewater. The suppression of electron-hole recombination rate was obtained after creation of the ternary heterostructure. Accordingly, the enhanced photoactivity was found in the prepared heterojunction photocatalyst as expected. Complete removal of OTC was obtained under natural sunlight irra-diation. The removal of OTC follows the first-order reaction with the maximum rate constant of 0.023 min-1. The prepared photocatalyst still maintains its structural stability with high photocatalytic performance even after seven times of use. Photogenerated holes are the crucial species involved in the OTC removal while electrons and hydroxyl radicals play a subordinate role. Charge transfer at the interface of the ternary heterojunction is pro-posed to be the Z-scheme type. The present work shows a promising strategy to create a novel ternary hetero-junction with an enhanced photoactivity for complete detoxification of harmful OTC antibiotic in the environment.

Automated summary

One vital topic in photocatalysis research is the development of novel nanomaterials for the degradation of toxic pollutants in water under visible light. In this study, a g-C3N4/BiOCl/CdS heterojunction was successfully synthesized via a hydrothermal method for complete removal of oxytetracycline (OTC) antibiotic in wastewater. The ternary heterostructure effectively suppressed electron-hole recombination, resulting in enhanced photocatalytic activity. Full removal of OTC was achieved under natural sunlight irradiation, following a first-order reaction with a maximum rate constant of 0.023 min-1. The prepared photocatalyst exhibited structural stability and high performance even after multiple uses. Photogenerated holes played a critical role in the OTC removal, while electrons and hydroxyl radicals had a subordinate role. Charge transfer at the interface of the ternary heterojunction was proposed to be of Z-scheme type. This work demonstrates a promising strategy for the complete detoxification of harmful OTC antibiotic in the environment by creating an enhanced photoactive ternary heterojunction.