▎ 摘　　要

We report a photoelectrochemical(PEC) sensor for selective detection of ascorbic(AA) by introducing Z-scheme Bi2S3@nitrogen doped graphene quantum dots(Bi2S3@NGQDs) heterojunctions as efficient photoactive species. The Bi2S3@NGQDs were successfully prepared by a simple hydrothermal process, and the microstructures and components were investigated by various characterized techniques. The photocurrent of the Bi2S3@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 mu mol/L and 5-1380 mu mol/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.