Construction of a dual-functional CuO/BiOCl heterojunction for high-efficiently photoelectrochemical biosensing and photoelectrocatalytic degradation of aflatoxin B1

Aflatoxin B1 (AFB1) exposure often causes serious food safety problems and illnesses in humans and animals even at extremely low content. Therefore, ultrasensitive detection and effective degradation of AFB1 is vitally significant. Photoelectrochemical (PEC) approach has been widely applied in sensing and catalysis fields. For achieving robust PEC performance, exploring highly photoactive semiconductor materials is critical. Herein, we constructed a novel and dual-functional copper oxide/bismuth oxychloride (CuO/BiOCl) composite by in-situ growth of CuO on BiOCl surface. The photo-absorption region of CuO/BiOCl was efficaciously broadened from UV to visible range, making for enhanced light harvest. Meanwhile, the p-n heterostructure in CuO/BiOCl clarified that the formed built-in internal electric field could accelerate band-band transfer of carriers. Driven by this, PEC response of CuO/BiOCl was greatly boosted comparing with that of pure CuO or BiOCl. Further combing with the specific aptamer, a favorable CuO/BiOCl-based PEC biosensor was fabricated for AFB1 detection with ultra-sensitivity (detection limit of 0.07 pg mL(-1)) and satisfactory recoveries (96.4% similar to 105.7%) in real maize samples. Subsequently, under light irradiation and suitable bias voltage, a degradation rate of similar to 81.3% was facilely attained for 5.0 mu g mL(-1) AFB1, indicating excellent photoelectrocatalytic activity of CuO/BiOC1 material. The catalytic mechanism and the main product of AFB1 degradation were analyzed. Taken together, the heterostructured CuO/BiOCl-based PEC assay provides a potential way for monitoring and controlling the AFB1 contamination in the food security areas.

Automated summary

The study constructed a novel CuO/BiOCl composite which effectively broadened the photo-absorption region, enhanced light harvesting, and successfully fabricated a highly sensitive AFB1 detector. By combining with a specific aptamer, the composite material achieved ultra-sensitive detection and efficient degradation of AFB1, providing a potential pathway for monitoring and controlling AFB1 contamination in food security areas.