| Energy is the driving force and cornerstone for the survival and development of human society.With the progress and development of our human society,the development and utilization of energy is becoming more and more widely and extensive.Since the industrial revolution in the 19th century,the consumption of world energy has increased dramatically.Large quantities of organic fuels such as coal,oil and natural gas have brought serious environmental problems to both the ecological environment and human existence.At the same time,the reserves of these resource are very limited and the reserves is running out.As a new energy equipment,fuel cell attracts worldwide attention with high conversion rate,low cost,stable and environmental protection.Electrode catalyst is an important factor affecting the performance of a new energy equipment.The oxygen reduction reaction of fuel cell cathode determines the performance of a fuel cell.Therefore,developing excellent oxygen reduction catalyst is the key to popularizing and commercializing fuel cells.CoFe2O4,as a substitute for commercial Pt/C electric catalysts,has been made into many advanced composite materials such as CoFe2O4/carbon nanotubes(CNTs),CoF e2O4/mesoporous carbon,CoFe2O4/biocarbon and CoFe2O4/graphene.In this work,monodisperse CoFe2O4/reduced graphene oxide(rGO)nanoparticles have been successfully synthetized in one step from Co(II)acetylacetonate,Fe(III)acetylacetonate and graphene oxide(GO).A facile solvent method was designed to skillfully integrate the crystal growth process of CoFe2O4,the reduction process of GO and their compound process.In synthesis process,large numbers of defects on GO thin layers were smartly used to disperse CoFe2O4 nanoparticles.The micromorphology and the distribution of as-prepared samples were identified via X-ray diffraction(XRD),transmission electron microscope(TEM)and element mapping spectra.Results showed that monodisperse CoFe2O4 nanoparticles were uniformly coupled with rGO thin layers.Good performance for both oxygen reduction and oxygen evolution of as-prepared CoFe2O4/rGO(0.92 V onset potential for oxygen reduction and 1.59 V overpotential at 10 mA cm-2 for oxygen evolution,vs.RHE)were found during a series of electrochemical tests,which make it a promising bi-functional catalyst in the field of fuel cells and metal-air batteries. |
