A self-powered photoelectrochemical aptasensor based on core-shell Z-scheme Co3O4@ZnO/ZnO@Co3O4 heterojunction and bimetallic zeolitic imidazolate framework-derived templates for ultrasensitive detection chlorpyrifos.

Pesticide residues pose a serious threat to food safety and public health, making the development of rapid and sensitive on-site detection technologies a major challenge. Here a self-powered photoelectrochemical aptasensor is reported for ultrasensitive detection of chlorpyrifos in food samples. The sensor is based on a Z-scheme Co3O4@ZnO/ZnO@Co3O4 core-shell heterojunction, which enhances charge separation and photocurrent generation without an external power supply, aided by peroxymonosulfate (PMS) activation at the photocathode. Combined with aptamer-specific recognition, the platform achieves a broad linear detection range from 2.85 pM to 2.85 × 106 pM and a low detection limit of 2.71 pM. In real-sample analysis, it exhibits reliable performance and high anti-interference capability. This work provides an innovative Z-scheme heterojunction design and a portable sensing strategy for on-site pesticide residue monitoring in food safety applications.