Exploitation of a turn-on photoelectrochemical sensing platform based on Au/BiOI for determination of copper(II) ions in food samples

Abstract Copper is an essential element and plays an important role in various physiological processes. Therefore, it is critical to exploit novel assay for effective, rapid, simple and selective detection of copper. Herein, a cathodic turn-on photoelectrochemical (PEC) sensor was developed for the selective and accurate analysis of copper(II) ions (Cu2+) in food samples based on the gold nanoparticles (AuNPs) loaded BiOI nanocomposite (Au/BiOI). By screening and optimizing bismuth oxyhalide semiconductors, the Au/BiOI with a wide visible light response range and low electron recombination efficiency was prepared. Compared with the BiOI alone, the Au/BiOI exhibited about 4-hold enhanced photocurrent intensity. Based on the excellent PEC performances, the Au/BiOI were successfully applied to construct the Cu2+ PEC sensor. Under the optimized conditions, the Au/BiOI-based PEC sensor exhibited excellent linear response with the concentration of Cu2+ from 1 to 50 μM and a low limit of detection (0.4 μM). Moreover, this PEC sensing strategy exhibited a feasible method for Cu2+ detection in food samples with high selectivity and good stability.