Rational　design　of　photocatalyst　with　efficient　performance　in　water　splitting　is　highly　desired　for　solar　energy　utilization.　In　this　work,　a　simple　and　facile　strategy　was　developed　to　synthesize　Mo　doped　graphic　carbon　nitride　(g-C3N4)　by　a　two-step　thermal　treatment　process.　As　obtained　product　exhibits　sheet-like　morphology　with　porous　structure,　and　the　formation　mechanism　could　be　ascribed　to　the　exfoliation　effect　in　thermal　environment.　Photocatalytic　property　investigation　reveals　that　Mo　doped　g-C3N4　nanosheets　present　greatly　improved　hydrogen　evolution　rate　of　1.6　mmol　g(-1)　h(-1)　under　visible　light,　which　is　about　9.4　times　higher　than　that　of　pristine　g-C3N4.　The　improved　performance　could　be　well　attributed　to　its　enhanced　visible　light　absorption,　well　suppressed　carrier　recombination　and　greatly　increased　specific　surface　area.　Accordingly,　our　work　provides　a　promising　and　straight　forward　way　to　develop　advanced　photocatalyst　with　high　efficiency　for　renewable　energy　generation.　(C)　2020　Elsevier　B.V.　All　rights　reserved.