Oxygen-andnitrogen-functionalizedcarbonnanotubes(OCNTsandNCNTs)wereappliedasmetal-freecatalystsinselectiveolefinhydrogenation.AseriesofNCNTswassynthesizedbyNH3post-treatmentofOCNTs.Temperature-programmeddesorption,N2physisorption,Ramanspectroscopy,high-resolutiontransmissionelectronmicroscopyandX-rayphotoelectronspectroscopywereemployedtocharacterizethesurfacepropertiesofOCNTsandNCNTs,aimingatadetailedanalysisofthetypeandamountofoxygenandnitrogen-containinggroupsaswellassurfacedefects.Thegas-phasetreatmentsappliedforoxygenandnitrogenfunctionalizationatelevatedtemperaturesupto600Cledtotheincreaseofsurfacedefects,butdidnotcausestructuraldamagesinthebulk.NCNTsshowedaclearlyhigheractivitythanthepristineCNTsandOCNTsinthehydrogenationof1,5-cyclooctadiene,andalsotheselectivitytocyclooctenewashigher.Thefavorablecatalyticpropertiesareascribedtothenitrogen-containingsurfacefunctionalgroupsaswellassurfacedefectsrelatedtonitrogenspecies.Incontrast,oxygen-containingsurfacegroupsandthesurfacedefectscausedbyoxygenspeciesdidnotshowclearcontributiontothehydrogenationcatalysis.
