[Jacs Articals]Simultaneous Nitrogen Doping and Reduction of Graphene.pdf

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1、PublishedonWeb10/09/2009SimultaneousNitrogenDopingandReductionofGrapheneOxideXiaolinLi,HailiangWang,JoshuaT.Robinson,HernanSanchez,GeorgiDiankov,andHongjieDai*DepartmentofChemistry,StanfordUniVersity,Stanford,California94305ReceivedAugust21,2009;E-mail:hdai@stanford.eduAbs

2、tract:WedevelopedasimplechemicalmethodtoobtainbulkquantitiesofN-doped,reducedgrapheneoxide(GO)sheetsthroughthermalannealingofGOinammonia.X-rayphotoelectronspectroscopy(XPS)studyofGOsheetsannealedatvariousreactiontemperaturesrevealsthatN-dopingoccursatatemperatureaslowas300

3、°C,whilethehighestdopinglevelof∼5%Nisachievedat500°C.N-dopingisaccompaniedbythereductionofGOwithdecreasesinoxygenlevelsfrom∼28%inas-madeGOdownto∼2%in1100°CNH3reactedGO.XPSanalysisoftheNbindingconfigurationsofdopedGOfindspyridinicNinthedopedsamples,withincreasedquaternaryN(Nt

4、hatreplacedthecarbonatomsinthegrapheneplane)inGOannealedathighertemperatures(g900°C).OxygengroupsinGOwerefoundresponsibleforreactionswithNH3andC-Nbondformation.PrereducedGOwithfeweroxygengroupsbythermalannealinginH2exhibitsgreatlyreducedreactivitywithNH3andalowerN-dopingle

5、vel.ElectricalmeasurementsofindividualGOsheetdevicesdemonstratethatGOannealedinNH3exhibitshigherconductivitythanthoseannealedinH2,suggestingmoreeffectivereductionofGObyannealinginNH3thaninH2,consistentwithXPSdata.TheN-dopedreducedGOshowsclearlyn-typeelectrondopingbehaviorw

6、iththeDiracpoint(DP)atnegativegatevoltagesinthreeterminaldevices.OurmethodcouldleadtothesynthesisofbulkamountsofN-doped,reducedGOsheetsusefulforvariouspracticalapplications.Introductionandsuggestedreactionsoccurringmostlyattheedgesanddefect61sitesongraphene.SubstitutionalN

7、-dopedmultiplayergrapheneGrapheneexhibitsvariousinterestingphysicalproperties,2sheetsweresynthesizedbyLiuetal.byaddingNH3gasduringlargesurfaceareas(∼2600m/g),andhighchemicalstability,11chemicalvapordeposition(CVD)growthofgraphene.N-allofwhichcouldbeutilizedforpotentialappl

8、icationsincluding2,3dopedgraphitewasalsopreparedbyarcdischargeofcarbongraphenenanoribbonfi