Hydrogen　production　by　semiconductor　photocatalysis　using　abundant　sunlight　and　water　is　an　ideal　method　to　address　the　globe　energy　and　environment　issues.　Here,　we　present　a　facile　synthesis　of　bromine　doped　graphitic　carbon　nitride　(g-C3N4)　photocatalysts　for　hydrogen　evolution　with　visible　light　irradiation.　Bromine　modification　is　shown　to　enhance　the　optical,　conductive　and　photocatalytic　properties　of　g-C3N4,　while　still　keeping　the　poly-tri-s(triazine)　core　structure　as　the　main　building　blocks　of　the　materials.　This　modification　method　can　be　generally　applicable　to　several　precursors　of　g-C3N4,　including　urea,　dicyandiamide,　ammonium　thiocyanide,　and　thiourea.　The　optimal　sample　CNU-Br-0.1　shows　more　than　two　times　higher　H-2　evolution　rates　than　pure　CNU　sample　under　visible　light　irradiation,　with　high　stability　during　the　prolonged　photocatalytic　operation.　Results　also　found　that　the　photocatalytic　O-2　evolution　activity　of　CNU-Br-0.1　was　promoted　when　the　sample　was　subjected　to　surface　kinetic　promotion　by　loading　with　cobalt　oxide　as　a　cocatalyst.　This　study　affords　us　a　feasible　modification　pathway　to　rationally　design　and　synthesize　g-C3N4　based　photocatalysts　for　a　variety　of　advanced　applications,　including　CO2　photofixation,　organic　photosynthesis　and　environmental　remediation.　(C)　2016　Elsevier　B.V.　All　rights　reserved.