Highly efficient Z-scheme CeO 2 /Bi 2 MoO 6 heterojunction strengthened by redox mediator for photoelectrochemical detection of tetracycline with enhanced sensitivity

Accurate monitoring of antibiotics that pose risks to the environment and human health is essential. The photoelectrochemical system has emerged as a rapid and precise method for detecting environmental pollutants. However, current photoelectrochemical materials made of semiconductors face challenges due to poor photoelectric conversion efficiency. In this study, a Z-scheme CeO /Bi MoO heterojunction structure was successfully prepared by a cost-effective hydrothermal method. By leveraging built-in electric field and the Ce /Ce redox mediator, this heterojunction achieved high photoelectrochemical conversion efficiency and functioned effectively as a sensor for tetracycline (TCH). The designed sensor demonstrated two linear ranges of 0.05-100 nM and 100-300 nM with an ultra-low detection limit of 15.4 pM for TCH. Additionally, the sensor exhibited excellent selectivity and high stability, demonstrating its potential for TCH detection in tap-water and milk samples. This study presents a simple and reliable method for the practical detection of antibiotic residues in environmental and food samples.