A Label-free Photoelectrochemical Sensor Based on Bi2S3@Nitrogen Doped Graphene Quantum Dots for Ascorbic Acid Determination

We report a photoelectrochemical(PEC) sensor for selective detection of ascorbic(AA) by introducing Z-scheme Bi 2 S 3 @nitrogen doped graphene quantum dots(Bi 2 S 3 @NGQDs) heterojunctions as efficient photoactive species. The Bi 2 S 3 @NGQDs were successfully prepared by a simple hydrothermal process, and the microstructures and components were investigated by various characterized techniques. The photocurrent of the Bi 2 S 3 @NGQDs-based sensor increased significantly in the presence of AA and showed excellent selectivity and stability for AA detection in the presence of some other antioxidants and small molecules. A wide linear range of 0.1–5 µmol/L and 5–1380 µmol/L was achieved for the AA detection with a detection limit of 36 nmol/L( S / N =3). Moreover, the proposed PEC sensor achieved the determination of AA in real red peppers and commercially available vitamin C tablets samples.