New functionalized graphene sheets for enhanced oxygen reduction as metal-free cathode electrocatalysts

Tridodecylmethylammonium chloride (TDMAC) functionalized reduced graphene oxide (TDMAC-RGO) has synthesized by a simple physicochemical process. The resultant functionalized graphene imparts electrocatalytic activity as metal- free catalysts for the oxygen reduction reaction (ORR) in fuel cells (FCs), with long-term operational stability, and tolerance to methanol and ethanol via a four-electron pathway in alkaline FCs. The ORR activities have systematically investigated by cyclic voltammetry (CV) and rotating ring disk electrode (RRDE) techniques. The results show that the TDMAC-RGO demonstrates excellent catalytic activity for oxygen reduction. Raman and X-ray photoelectron spectroscopic (XPS) measurements indicate charge transfer from the graphene sheets to the TDMAC via intermolecular charge-transfer. TDMAC-RGO catalysts are low-cost, free of metal and costly polymers, and are an efficient approach to FC applications. (C) 2012 Elsevier B.V. All rights reserved.