Nanocomposite integrating tube-like NiCo2S4 and carbon nanotubes for electrooxidation of methanol
Fen-Kuan Chen, Yi-Hua Ho, Han-Wei Chang, Yu-Chen Tsai
Abstract
An effective and simple strategy for fabricating a NiCo2S4/CNT nanocomposite by combining carbon nanotubes (CNTs) with tube-like NiCo2S4 is proposed, with the aim of producing a successful catalyst for the electrooxidation of methanol. Tube-like NiCo2S4 was successfully synthesized through a hydrothermal sulfurization process. The carbon nanotubes have high conductivity and provide conductive contact with the tube-like NiCo2S4, making the composite an excellent choice of electrode material for direct methanol fuel cells (DMFC). Field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) were used to characterize and investigate the morphological and physicochemical properties of the nanocomposite. The results of these studies helped in evaluating the electrocatalytic behavior of the material and exploring its potential for use in DMFC. Electrocatalytic behavior towards methanol oxidation was studied by electrochemical methods (cyclic voltammetry (CV) and chronoamperometry (CA)), which show that the tube-like NiCo2S4/CNT nanocomposite exhibits excellent electrocatalytic performance for electrooxidation of methanol in an alkaline medium, with a high current density (~160 mA cm−2) and excellent stability (~83% retention after 500 CV cycles). The results presented here clearly indicate that the proposed tube-like NiCo2S4/CNT nanocomposite has potential for applications in DMFCs.