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-Br0.1　shows　more　than　two　times　higher　H2　evolution　rates　than　pure　CNU　sample　under　visible　light　irradiation,　with　high　stability　during　the　prolonged　photocatalytic　operation.　Results　also　found　that　the　photocatalytic　O2　evolution　activity　of　CNU-Br0.1　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.　©　2016.