Structure characteristic of titanium nitride nanowires and its electrode processes for V(II)/V(III) redox couple

Abstract

Titanium nitride nanowires (TiN NWs) were directly prepared on a Ti foil by a hydrothermal method followed by nitridation in ammonia atmosphere. The composition, microstructure, and electrochemical properties of the TiN NWs were characterized using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry(CV), and electrochemical impedance spectroscopy (EIS). The results show that the nanowires have diameters of 20−50 nm and are 5 μm long. The surfaces of the TiN NWs comprise Ti－N, Ti－O, and O－Ti－N chemical states. The electrochemical activity and reversibility for the electrode processes of V(II)/V(III) couple on the TiN NWs are significantly improved due to the introduced Ti－N, Ti－O, and O－Ti－N chemical states. The transfer resistance for the cathodic reduction of V(III) on the TiN NWs is about 20 times and 10 times smaller than on TiO2 NWs and graphite electrodes, respectively. The rate constant of charge transfer on the TiN NWs electrode was determined to be 5.21×10−4 cm·s−1, which is about 5 times larger than the rate constant on graphite electrodes (9.63×10−5 cm·s−1).