As　an　efficient　but　mild　oxidation　species,　O2[rad]–　generated　from　surface　O2　and　photo-excited　electrons　plays　a　key　role　in　photocatalytic　reactions.　To　improve　photocatalytic　activity,　it　is　essential　to　facilitate　the　separation　and　transfer　efficiency　of　photogenerated　charge　carriers.　In　this　work,　Mo2C-QDs/C,　an　alternative　of　noble　metals,　was　used　as　an　efficient　and　economical　cocatalyst.　It　was　added　to　Bi2MoO6　nanosheet　to　generate　Mo2C-QDs/C/Bi2MoO6　(MCBMO)　composites　by　a　facile　hydrothermal　method.　Under　visible　light　irradiation,　the　carbon　layer　and　the　Mo2C-QDs　acts　as　electronic　conductor　and　electron　trapping　agent　to　promote　the　transfer　of　photogenerated　electrons　for　enhanced　generation　of　O2[rad]–.　The　MCBMO　composites　show　boosted　photocatalytic　performance　in　the　oxidative　coupling　of　benzylamine　to　N-benzylbenzaldimine　with　excellent　recyclability.　Under　the　optimized　conditions,　benzylamine　conversion　over　the　optimized　MCBMO-3　composite　is　up　to　92%　whereas　that　over　pristine　Bi2MoO6　is　limited　to　53%.　The　MCBMO-3　composite　even　outperforms　Ag/Bi2MoO6　and　Pt/Bi2MoO6.　Based　on　the　results　of　ESR　and　active　species　trapping　studies,　it　is　confirmed　that　O2[rad]–　and　h+　are　indispensable　in　the　photocatalytic　reaction,　and　a　possible　reaction　mechanism　has　been　proposed.　©　2020