Sulfur-Doped Graphitic Carbon Nitride/Bi Nanospheres/Bismuth Tungstate Microflowers Ternary Composites-Based...

The development of efficient and durable electrochemical sensor electrode materials is essential for real-time analysis. Graphitic carbon nitride (g-C₃N₄) nanostructures have emerged as a new generation of sensing platforms for electrochemical detection of hazardous pollutants, owing to their abundant functional amino groups, tunable nanostructures, high density of active sites and superior physicochemical properties. In this study, sulfur-doped graphitic carbon nitride (SCN) was synthesized via thermal polycondensation, followed by the fabrication of bismuth nanospheres (BiNSs) and bismuth tungstate (BWO) through a solvothermal method. BiNSs exhibit excellent electrical conductivity and strong affinity toward Pb²⁺ ions, while BWO possesses a unique heterojunction-regulating ability and oxygen vacancy structure. Both components synergistically interact with SCN to construct a composite system with complementary functionalities. The SCN/BiNSs/BWO nanocomposite was employed as a signal probe for Pb²⁺ detection. Under optimized conditions, namely pH = 5 with a deposition potential of -0.9 V and a deposition time of 180 s in (sodium acetate-acetic acid) NaAc-HAc buffer, the sensor demonstrated excellent performance, yielding a detection limit of 0.04 μM and a linear range of 0.1-4.5 μM. The SCN/BiNSs/BWO-modified glassy carbon electrode (GCE) demonstrated excellent stability. Recovery rates for Pb²⁺ detection in real water samples ranged from 94.7 to 109.0%, highlighting the significant practical application potential of the proposed electrode material.