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　H2　production　and　stronger　photocurrent　responses　under　visible　light　irradiation.　Further,　the　long-term　photocatalytic　test　proved　high　stability　of　the　prepared　nanoporous　microsphere　for　H2　generation.　©　2014　Elsevier　B.V.