Tungsten doped Co–Se nanocomposites as an efficient non precious metal catalyst for oxygen reduction

In this report, powder of tungsten doped Co–Se catalysts have been synthesized by decarbonylation of Co4(CO)12 and W(CO)6 in 1,6-hexanediol solvent dissolved Se element. Physical and electrochemical characteristics of the prepared samples are evaluated by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and rotating disk electrode (RDE) techniques. These catalysts show surface morphologies agglomerated nanometric particles and present the structural characteristics of orthorhombic CoSe2 and form tungsten oxide (WO3). The catalytic properties of the Co–W–Se catalysts for the oxygen reduction reaction (ORR) change with doping tungsten content in O2-saturated 0.5 M H2SO4 electrolyte, and the catalyst contained 1.49 mol% W presents the highest activity with an open circuit potential of 0.81 V. The measured transfer coefficient and Tafel slope of the catalyst is 0.49 and 0.120 V in the potential region of 0.64–0.76 V (vs. SHE), respectively. Therefore, doping W will be a promising approach to improving the ORR activity of non precious metal catalysts.