Highly efficient Z-scheme CeO2/Bi2MoO6 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 CeO2/Bi2MoO6 heterojunction structure was successfully prepared by a cost-effective hydrothermal method. By leveraging built-in electric field and the Ce3+/Ce4+ 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. [Display omitted] •CeO2/Bi2MoO6 heterojunction was used as PEC platform for sensing of tetracycline.•Built-in electric field and Ce3+/Ce4+ mediator enhanced the PEC conversion efficiency.•Tetracycline could be detected with an ultra-low detection limit of 15.4 pM.•The PEC sensor was successfully applied to detect Tetracycline in real samples.