3D flower-like β-Ni(OH)2 as an electrochemical sensor for sensitive determination of serotonin

Morphology studies of nanomaterials have attracted considerable attention in the field of catalysis because of their distinguishable properties and performances. In this context, we have developed a beta-Ni(OH)2 decorated para-phenylenediamine (p-PDA) functionalized reduced graphene oxide (RGO) (denoted as RGO/p-PDA/beta-Ni (OH)2) electrochemical sensor for detecting serotonin (5-HT). The growth mechanism of a three-dimensional (3D) flower-like beta-Ni(OH)2 based on two-dimensional (2D) RGO nanosheets assembled with petals of the flower was investigated by field emission scanning electron microscopy (FESEM). The 3D flower-like morphology significantly enhanced the surface area and conductivity of RGO/p-PDA/beta-Ni(OH)2 modified glassy carbon electrode (GCE). The electrochemical performance of the material was studied using different techniques, including cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectra (EIS), and amperometry. The higher oxidation current of RGO/p-PDA/beta-Ni(OH)2/GCE was -134.8 mu A at 0.383 V (vs Ag/AgCl) in CV. In amperometry, the modified electrode provided a wide linear range (5-325 mu M), low limit of detection (0.0462 mu M), high sensitivity (339.46 mu A mM-1 cm-2), and fast response time (<2 s). Furthermore, the as-prepared electrode demonstrated high selectivity, long-term stability, reproducibility, and repeatability. The much better recovery range of urine (109.83-111.05%) than drinking water (98.15-101.02%) implied that the sensor is effective for 5-HT determination.