Facile synthesis of gadolinium vanadate nanowires for sensitive detection of cobalt ions

Gd vanadate nanowires were synthesized by a facile one-step hydrothermal route and characterized by X-ray diffraction, electron microscopy and X-ray photoelectron spectroscopy. The obtained nanowires consist of single crystalline tetragonal GdVO4 phase. The length and diameter of the nanowires with smooth surface are longer than 20 µm and 20–100 nm, respectively. The formation mechanism of the Gd vanadate nanowires was analyzed by the structural and morphological evolution of the intermediates obtained from various conditions. The Gd vanadate nanowires modified glassy carbon electrode (GCE) shows fast electron transfer and efficient electro-catalytic behaviour between Co2+ and Gd vanadate nanowires modified electrode. By square wave voltammetry (SWV) technique, the electrochemical detection of Co2+ using the Gd vanadate nanowires modified electrode was investigated. The buffer solution pH value, deposition time, deposition potential and standing time were optimized to be pH = 6, 60 s, −1.5 V and 30 s, respectively. A linear working range of 0.01–1000 μM was established between the anodic current and Co2+ concentration with the detection limit of 0.32 nM. Under optimized measurement parameters, the proposed Gd vanadate nanowires modified GCE demonstrates low detection limit, wide linear range, good stability, repeatability, selectivity and reproducibility for Co2+ detection. The Gd vanadate nanowires modified electrode shows promising application potential for Co2+ detection in real samples.