Developing　highly　active　and　stable　nanocarbon　catalysts　for　selective　oxidation　reactions　has　attracted　much　attention　due　to　their　potential　as　an　alternative　to　traditional　metal-based　or　noble　metal　catalysts.　However,　the　nature　of　active　sites　and　the　reaction　mechanism　of　nanocarbon　catalysts　for　oxidation　reactions　still　remains　largely　unknown,　which　hinders　the　rational　design　and　development　of　highly　efficient　carbon-based　catalysts.　Here　we　report　a　facile　strategy　for　the　synthesis　of　boron　and　nitrogen　co-doped　carbon　nanosheet　material　(BNC),　which　exhibits　excellent　catalytic　activity　with　91%　conversion　and　99%　selectivity　in　selective　oxidation　of　benzyl　alcohol　into　benzaldehyde,　superior　to　those　of　traditional　carbon　materials　(oxidized　carbon　nanotubes,　graphites　and　commercial　nanocarbons).　Structural　characterizations　and　kinetic　measurements　are　studied　to　clarify　the　active　site,　in　which　phenolic　hydroxyl　on　BNC　is　responsible　for　the　production　of　benzaldehyde.　Meanwhile,　we　put　forward　a　possible　reaction　mechanism　and　point　out　the　key　factors　in　determining　the　reactivity　for　this　reaction.　Therefore,　the　present　work　provides　new　insight　into　structure–function　relationships,　paving　the　way　for　the　development　of　highly　efficient　nanocarbon　catalysts.　©　2021　Elsevier　Inc.