# Construction of S-Scheme BiVO4/Bi2O2S Heterojunction for Highly Effective Photocatalysis of Antibiotic Pollutants

## TL;DR

A new photocatalyst, BiVO4/Bi2O2S, was developed to efficiently break down tetracycline in wastewater under visible light.

## Contribution

The study introduces an S-scheme heterojunction that enhances charge separation and photocatalytic efficiency for antibiotic degradation.

## Key findings

- The BiVO4/Bi2O2S composite achieved 82.9% tetracycline degradation under visible light in 90 minutes.
- The composite's reaction rate was 3.19 times higher than pure BiVO4 and 2.66 times higher than pure Bi2O2S.
- An S-scheme charge transfer mechanism was identified as the key to improved photocatalytic performance.

## Abstract

Photocatalytic processes have emerged as an efficacious strategy for the removal of organic pollutants from wastewater. In the present investigation, a BiVO4 nanorod supported on Bi2O2S nanosheet catalyst (referred to as BiVO4/Bi2O2S) was meticulously synthesized via a straightforward synthetic approach, aimed explicitly at the photodegradation of tetracycline (TC). The optimized BiVO4/Bi2O2S composite, with a theoretical weight ratio of BiVO4 to Bi2O2S at 2:1 (designated as 2BVO/BOS), demonstrated a significant improvement in tetracycline degradation efficiency, achieving up to 82.9% under visible light irradiation for 90 min. This result stands in stark contrast to the relatively low degradation rates of 42.9% and 50.7% observed for pure BiVO4 and Bi2O2S, respectively. Furthermore, the apparent reaction rate of 2BVO/BOS (approximately 0.01894 min−1) was 3.19-fold and 2.66-fold higher than those of BiVO4 (0.00594 min−1) and Bi2O2S (0.00713 min−1), respectively. This significant improvement in photocatalytic efficacy can be ascribed to the composite’s superior capacity for visible light absorption, as well as its remarkable proficiency in charge carrier separation and transfer. Comprehensive experimental analyses, corroborated by extensive characterization techniques, revealed the formation of a distinctive S-scheme charge transfer mechanism at the interface between BiVO4 and Bi2O2S. This mechanism effectively suppresses charge recombination and optimizes the redox potentials of the photogenerated carriers, thereby enhancing the overall photocatalytic performance. The current study underscores the remarkable potential and promising application of BiVO4/Bi2O2S composite in the realm of wastewater treatment.