Pt anchored functionalized graphene nanosheets: A stable oxygen reduction electrocatalyst in alkaline electrolyte.

A Platinum-based graphene nanosheet electrocatalyst (Pt/GNS) was modified by changing its surface chemical composition (or functionalization), using citric acid via solid state method. The physical characterizations were orderly carried out by Raman spectroscopy, Fourier transform infrared spectroscopy, thermo-gravimetric analysis,X-ray powder diffraction, field emission scanning electron microscope, and transmission electron microscope. Electrocatalytic activity concerningto oxygen reduction reaction (ORR) of the synthesized catalyst was measured using a rotating disk electrode coupled with potentiostat/galvanostatinalkaline (0.1 M KOH) solution, and the performance was compared to conventional Pt/C catalyst. The developed electrocatalyst holds superior electrocatalytic properties compared to the unfunctionalized catalyst and Pt/C. Functionalized Pt/GNS exhibited better oxygen reduction activity of (0.86 V half-wave potential) and demonstrated 3.9 e− transfer against a single oxygen molecule. After 10,000 potential cycles of stability performance, the developed electrocatalyst showed remarkable durability. • Pt anchored graphene nanosheets were employed as electrocatalyst for ORR. • Pt/GNS was functionalized by using citric acid via the solid state method. • Pt/GNS showed improved electrocatalytic activity for ORR. • Pt/GNS showed the long-term stability towards ORR activity. [ABSTRACT FROM AUTHOR]