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.