A　sheet-on-sheet　and　metal-free　graphene/C3N4/carbon　dots　(GR/C3N4/CDots)　ternary　heterostructure　with　efficient　visible-light　photocatalysis　for　pollutants　degradation　has　been　reported.　Via　a　convenient　and　hydrothermal　method,　large-sized　GR　nanosheets　can　serve　as　substrate　for　monodispersed　dispersion　of　C3N4　nanosheets.　A　subsequent　loading　of　very　small　amount　of　CDots　(1　wt%,　2-5　nm)　onto　sheet-on-sheet　heterostructure　significantly　enhance　visible-light-driven　photoredox　performances　of　catalysts,　including　oxidation　of　organics　pollutant　(RhB,　96.0%)　and　reduction　of　heavy　metals　[Cr(VI),　83.6%].　Excellent　catalytic　properties　of　GR/C3N4/CDots　heterostructure　can　be　predominantly　ascribed　to　the　intimate　interfacial　contact　among　constructing　ingredients,　increased　specific　surface　area　and　enhanced　light　adsorption　derived　from　GR　and　CDots　carbon　materials.　Particularly,　the　synergistic　sheet-on-sheet　interaction　between　C3N4　and　carbon　materials　(GR　and　CDots)　remarkably　accelerate　the　electrons/holes　separation,　giving　rise　to　significantly　enhanced　photoredox　performances　of　GR/C3N4/CDots　in　comparison　with　other　counterparts.　The　synergism　effect　between　organic　contaminants　and　heavy　metals　also　contributed　to　the　efficient　performance　of　GR/C3N4/CDots,　wherein　the　O2-　and　OH　were　the　main　active　species　in　the　photoredox　reactions.　This　metals-free　heterostructure　shows　favorable　photostability　in　cyclic　experiments.　We　anticipate　that　our　work　could　provide　a　classical　paradigm　for　rational　design　of　efficient　and　visible-light-driven　photocatalysts　for　their　sustainable　applications　in　wastewater　treatment.　(C)　2016　Published　by　Elsevier　B.V.