Threetypesofcarbonnano-onions（CNOs）includingNi@CNOs.Fe3C@CNOsandFe0.64Ni0.36@CNOsnanoparticleshavebeensynthesizedbycatalyticdecompositionofmethaneat850℃usingnickel,ironandiron-nickelalloycatalysts.Comparativeandsystematicstudieshavebeencarriedoutonthemorphology,structuralcharacteristicsandgraphiticcrystallinityoftheseCNOsproducts.Furthermore,theelectrochemicalhydrogenstoragepropertiesofthreetypesofCNOshavebeeninvestigated.MeasurementsshowthattheNi@CNOshavethehighestdischargecapacityof387.2mAh/g,coiTespondingtoahydrogenstorageof1.42%.ThiscomparisonstudyshowstheadvantagesofeachcatalystinthegrowthofCNOs.enablingthecontrollablesynthesisandtuningthepropertiesofCNOsbymediatingdifferentmetalsandtheiralloyforusinginthefuelcellsystem.
