Electron Microscopy Investigation of FeNi/NrGO Nanocomposite Catalysts for Fuel Cells Application

Abstract

High efficiency but low cost FeNi nanoparticles supported on NG (nitrogen-doped graphene) catalysts for ORR (oxygen reduction reaction) were prepared by electrodeposition method. NG was obtained via thermal annealing of ball milled graphene with melamine. XRD (X-ray diffraction), Raman, and XPS (X-ray photoelectron spectroscopy) analyses showed multiple layers with a low degree of disorder and characteristic of pyridinic-N were a major feature. The deposition of FeNi was carried out potentiostatically with voltage of -7.0 and -6.0 V for 100 s at room temperature. Different concentration of FeCl2·4H2O and NiCl2·6H2 O in ethylene glycol solution was varied. XRD patterns confirmed FeNi alloy formation and SEM (scanning electron microscopes) images reviewed that 0.025 M FeNi solution achieved spherically dispersed FeNi nanoparticles with diameters of 50-100 nm cover on NG particles and some parts appear as corals shape dendrite cluster. Only spherical particles were observed in other conditions. Average sizes of particle vary without trend. CV analysis shows that catalysts prepared with 0.50 M and at -7.0 V which has the smallest particle sizes, gave higher performance over others and commercial Pt/C catalysts. Therefore, this catalyst is expected to have good performance in ORR.