Synthesis of ZnO/ZnS/g‐C3n4 Nanocomposite for the Sensitive and Selective Electrochemical Detection of Ascorbic Acid

In this study, ZnO/ZnS/g‐C 3 N 4 composite materials were successfully synthesized via a combination of hydrothermal treatment and calcination for the electrochemical detection of ascorbic acid (AA). A systematic experimental design was implemented to evaluate the influence of key parameters, including the amount of ZnS added, the loading ratio of ZnO/ZnS onto g‐C 3 N 4 , and the pH conditions during detection, on sensor performance. Comprehensive material characterization was conducted using scanning electron microscopy transmission electron microscopy X‐ray diffraction, X‐ray photoelectron spectroscopy, and Fourier‐transform infrared spectroscopy, providing detailed insights into the composites’ microstructure, crystallinity, elemental composition, and chemical bonding. The sensor exhibited excellent performance for AA detection, with a broad linear detection range of 20–5000 μM, a low detection limit of 1.2 μmol/L (S/N = 3), and high recovery rates between 98.23% and 105.02%, accompanied by low relative standard deviations (1.56–3.12%). Furthermore, application of the sensor in cyclic voltammetry analysis of commercial vitamin C tablets yielded accurate and reliable results, confirming its strong stability, anti‐interference capacity, and reproducibility.