Target-assisted self-powered photoelectrochemical sensor based on AgS/BiOCl heterojunction for ultrasensitive chlorpyrifos detection.

Chlorpyrifos (CPF), a widely used organophosphorus pesticide, presents substantial risks to both environmental and human health due to its persistent accumulation, thereby necessitating the development of effective detection methods. Self-powered photoelectrochemical (PEC) sensors, as an innovative technology, address the limitations inherent in conventional sensors, such as susceptibility to interference and inadequate signal response. Herein, we synthesized AgS/BiOCl as a photosensitive material, employing it as a light-harvesting substrate and a signal-transducing platform to develop a self-powered PEC sensor for the detection of CPF. AgS/BiOCl composite exhibited a markedly enhanced photocurrent response in comparison to either AgS or BiOCl individually. CPF possesses distinctive chemical bonds, and upon incubation on the electrode surface, it forms chelates with Bi (III) within the AgS/BiOCl heterojunction. This interaction effectively impedes the transfer of photogenerated charges, resulting in a pronounced decrease in the original PEC signal, thereby facilitating the rapid and sensitive detection of CPF. This self-powder PEC sensor exhibited excellent linearity over the concentration range of 10.0 pg mL-100.0 ng mL, with a detection limit of 1.5 pg mL. The successful application of this work in real samples highlights its strong potential for monitoring of CPF residues, while also demonstrating its broader applicability for detecting other contaminants.