Fe 2 O 3 /g‐C 3 N 4 Composite Nanoparticles for Electrochemical Dopamine Sensing

Abstract A series of Fe₂O₃/g‐C₃N₄ composites with varying ratios were synthesized and characterized using XRD, TEM, SEM, and EDS to confirm their structural and morphological properties. Among these, the Fe₂O₃/g‐C₃N₄ (3:1) composite exhibited optimal performance in dopamine (DA) sensing, demonstrating enhanced signal intensity, recyclability, and stability compared to other ratios. Electrochemical analysis revealed high linearity, with R 2 values of 0.9909 (1:1) and 0.9944 (1:3), while the 3:1 composite displayed steeper slopes in CV (cyclic voltammetry) and DPV (differential pulse voltammetry) curves, indicating superior sensitivity. The composite enabled dopamine (DA) detection within a linear range of 6.25–200 µM, achieving a low detection limit (DL) of 0.35 µM. Selectivity tests against ascorbic acid (AA) and uric acid (UA) confirmed the sensor's specificity, with no significant interference observed. The results highlight the Fe₂O₃/g‐C₃N₄ (3:1) composite as a promising material for electrochemical DA detection, offering improved signal integrity and robustness—particularly at low concentrations. Future work will focus on validating the sensor in biological matrices for practical applications.