Heterostructured CuO-g-C3N4 nanocomposites as a highly efficient photocathode for photoelectrochemical aflatoxin B1 sensing

Abstract

Here, copper oxide-graphitic carbon nitride (CuO-g-C3N4) nanocomposites were facilely prepared and used as an efficient photosensitive material to construct a highly sensitive photoelectrochemical (PEC) sensor. The CuO-g-C3N4 nanocomposites were directly synthesized by in-situ growth of CuO on g-C3N4 nanosheets to form p-n heterojunction. The optical absorption of CuO-g-C3N4 nanocomposites was efficaciously broadened towards visible region through CuO doping. The heterostructured CuO-g-C3N4 permitted the photogenerated electrons of g-C3N4 to transfer to CuO and meanwhile the photogenerated holes of CuO to migrate to g-C3N4 under visible light irradiation. The effective carriers generation, separation and transfer processes endows CuO-g-C3N4 nanocomposites unique and greatly enhanced cathode photocurrent response as confirmed by a series of PEC studies. Further combining with molecular imprinted polymer (MIP) which acts as a recognition unit, we construct a favorable molecular imprinted polymer photoelectrochemical (MIP-PEC) sensor with high sensitivity for target aflatoxin B1 (AFB1) detection. Under optimal conditions, the proposed MIP-PEC sensor was successfully employed for AFB1 quantitative determination with a linear range of 0.01 ng mL−1 to 1 μg mL−1 and a detection limit of 6.8 pg mL−1. In addition, the sensor has excellent selectivity under high concentrations of interfering substances circumstance. The satisfactory AFB1 recoveries in maize solution illustrated the credible application of the proposed MIP-PEC sensors for real samples, indicating promising potential in food safety control.