Graphitic　carbon　nitride　microsphere　photocatalysts　were　prepared　through　a　template-free　solvothermal　approach　with　post-heating　treatment.　Structural　characterization　results　reveal　that　the　as-prepared　sample　has　the　same　composition　as　bulk　g-C3N4,　but　appears　as　hierarchical　microspheres　with　nanoporous　surfaces.　Comparing　to　the　bulk　g-C3N4,　these　porous　microspheres　exhibit　narrowed　bandgap　and　lower　resistance,　which　allows　more　effective　visible-light　harvesting　and　more　efficient　transport　and　separation　of　photogenerated　charge　carriers.　Consequently,　we　observed　high　rate　of　photocatalytic　H-2　production　and　stronger　photocurrent　responses　under　visible　light　irradiation.　Further,　the　long-term　photocatalytic　test　proved　high　stability　of　the　prepared　nanoporous　microsphere　for　H-2　generation.　(C)　2014　Elsevier　B.V.　All　rights　reserved.