Solvothermal synthesis of two-dimensional graphitic carbon nitride/tungsten oxide nanocomposite: a robust electrochemical scaffold for selective determination of dopamine and uric acid

A glassy carbon electrode was modified with a 2D-networked nanostructure composed of graphitic carbon nitride and tungsten oxide nanoparticles (2D-g-C3N4/WO3) to obtain a sensor for the concurrent determination of dopamine (DA) and uric acid (UA). The hybrid nanocomposite were prepared by a simple, one-pot pyrolysis method. The structure, morphology, and composition of g-C3N4/WO3 nanocomposites were characterized by powder X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy, thus confirming the successful synthesis of this composite and its physical features. Transmission electron microscope image showed WO3 nanoparticles with a diameter of 5–7 nm that were decorated on the surface of 2D g-C3N4 nanosheets. Owing to their peculiar morphological structure, 2D g-C3N4/WO3 offers an enriched electroactive surface area (0.098 cm2) with higher heterogeneous electron transfer kinetics (K° = 4.06 × 10−6 cm s−1) enhance the electrocatalytic activity toward the DA and UA detection than the other controlled electrode. The fabricated sensor showed a wide linear response 0.05–50 µmol L−1 and 0.01–900 µmol L−1 with the lower limits of detection of 11.9 and 2.27 nmol L−1 and higher sensitivity of 38.33 and 40.30 μA µmol L−1 cm−2, for DA and UA, respectively. Furthermore, the sensor fabricated in this study proved to be stable, reproducible, and repeatable. Analyses of DA and UA in human blood serum and urine samples revealed recovery of 99.78–103.3% and relation standard deviations of less than 1%, proving that the method can be used for real-life analysis.Graphical abstract Graphical illustration of 2D-g-C3N4-WO3 nanocomposite synthesis and application for the electrochemical determination of dopamine (DA) and uric acid (UA) in human blood serum and urine samples.