RGO/ZnWO4/Fe3O4 nanocomposite as an efficient electrocatalyst for oxygen reduction reaction

Abstract

Development of low cost, environmental friendly and noble metal free catalyst materials with excellent performance is essential for commercialization. In fact, this is the need of the day too. Herein, we report a facile microwave irradiation method for the synthesis of novel RGO/ZnWO<inf>4</inf>/Fe<inf>3</inf>O<inf>4</inf> cathode catalysts for the oxygen reduction reaction (ORR) in alkaline medium. The structural and morphological features of synthesized materials are fully examined using transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM). The chemical composition and elemental analysis of the catalyst is investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy techniques. Efficiency of RGO/ZnWO<inf>4</inf>/Fe<inf>3</inf>O<inf>4</inf> catalyst material for oxygen reduction reaction (ORR) in 0.1 M KOH is reported. The activity of catalyst is determined by linear sweep voltammogram (LSV) and rotating disk electrode (RDE) measurements in O<inf>2</inf> saturated 0.1 M KOH electrolyte. RGO/ZnWO<inf>4</inf>/Fe<inf>3</inf>O<inf>4</inf> catalyst exhibits higher ORR activity than RGO, ZnWO<inf>4</inf>, RGO/ZnWO<inf>4</inf> and its electrocatalytic performance is comparable to Pt/C material and is superior to it in stability and methanol tolerance. Further, it is determined that process follows a direct four electron reaction pathway. These combined results strongly signpost that RGO/ZnWO<inf>4</inf>/Fe<inf>3</inf>O<inf>4</inf> composite can function as an economic noble metal free ORR cathode catalyst for energy applications. © 2017 Elsevier B.V.