Edge-iodine/sulfonic acid functionalized graphene nanoplatelets as an efficient electrocatalyst for oxygen reduction reaction

Abstract

Development of electrocatalysts, along with cheap and available materials to facilitate oxygen reduction reaction (ORR) in fuel cells to replace Pt-based catalyst is an important issue in the development of fuel cells and other electro-chemical energy devices. The graphene provides good substitutes for electrode catalyst and some research have done to apply graphene nano-material into an cathodic catalyst as an ORR performance owing to its large surface area, the excellent conductivity, freely selectable functional groups such as atoms, molecules involved. It also can be noted that well-defined theoretical design of graphene-based nano-material with specific structure can perform important electro-chemical property in fuel cells ORR. Many studies have made for various hetero-atom based graphene nano-material or graphene-based nano-composites to reach goals which is its extraordinary characteristics for applications (ORR) in the fuel cells. It is reported that the synthesis of edge-iodine/sulfonic acid functionalized graphene nanoplatelets (ISGnP) via two-step sequential ball-milling graphite and their use as electrocatalyst for oxygen reduction reaction (ORR) in fuel cells. Graphite was ball-milled in presence of iodine to produce edge-iodine functionalized GnP (IGnP) in the first step and subsequently IGnP was ball-milled with sulfur trioxide to yield ISGnP. The resultant ISGnP was highly dispersible in various polar solvents, allowing the fabrication of electrodes for ORR using solution processing. The ORR performance of ISGnP in an alkaline medium was superior to commercial Pt/C in terms of electrocatalytic activity and cycle stability.