Nitrogen　doped　carbons　are　an　important　family　of　materials　with　ideal　activity　for　oxygen　reduction　reaction　(ORR).　It　is　always　interesting　to　search　functional　carbons　with　high　heteroatom　contents　and　desirable　structure　for　ORR.　Within　this　study,　the　surface　modification　of　carbon　nanotubes　(CNTs)　via　hydrothermal　carbonization　(HTC)　technique　in　the　presence　of　glucose　and　urea　was　reported,　where　the　surface　of　CNTs　is　successfully　coated　by　nitrogen　containing　hydrothermal　carbon　layers.　The　resulting　composite　combines　both　advantages　of　the　outstanding　electrical　conductivity　of　CNTs　and　the　effective　ORR　active　sites　provided　by　doped　nitrogen　in　the　HTC　carbon　layers.　By　controlling　the　ratio　of　glucose　and　urea,　the　nitrogen　contents　coated　on　the　surface　of　CNTs　can　reach　up　to　1.7 wt%.　The　resulting　materials　show　outstanding　electrochemical　activity　towards　ORR　in　alkaline　electrolyte,　making　it　one　of　the　valuable　metal-free　electrode　materials　and　a　competent　alternative　to　the　state-of-the-art　Pt/C　catalyst.　©　2017　Science　Press