Novel　3D　N-doping　Ta2O5　nanoflowers　(NFs)　photocatalysts　were　synthesized　at　different　annealing　temperatures　ranging　from　700　degrees　C　to　850　degrees　C.　The　microstructure,　phase　composition,　and　chemical　states　of　those　photocatalysts　were　characterized　in　details.　The　adsorption　kinetics　as　well　as　photocatalytic　performance　under　visible　light　irradiation　were　also　investigated.　Importantly,　compared　to　N-doping　Ta2O5　NFs　samples　obtained　at　other　nitriding　temperatures,　the　Ta2O5　NFs　nitrided　at　750　degrees　C　displayed　high　surface　adsorption　and　photocatalytic　degradation　activity　of　Methylene　Blue　(MB)　due　to　the　synergistic　effect　of　large　surface　area,　strong　surface　adsorption,　light　absorption　and　photosensitization.　The　experiment　results　confirmed　that　the　adsorption　of　MB　to　these　samples　and　photocatalytic　degradation　follow　the　pseudo-second　order　chemisorption　mechanism　and　pseudo　first　order　degradation　kinetics,　respectively.　The　main　reactive　species　were　identified　through　the　scavenging　reaction　following　the　order　of　h(+)　＞　center　dot　OH　＞　center　dot　O2-.　Additionally,　degradation　product　analysis　was　conducted　using　liquid　chromatography　tandem　mass　spectrometry　(LC-MS)　technique　combined　with　the　UV-vis　absorption　spectrum.　The　results　showed　that　the　degradation　was　initiated　by　demethylation　of　the　dye　molecule.　The　current　work　may　contribute　to　additional　applications　of　these　3D　N-doping　Ta2O5　hierarchical　nanostructures　such　as　photoelectric　chemical　(PEC)　water　splitting,　surface　adsorption,　supercapacitors,　solar　cells,　etc.　(C)　2016　Elsevier　B.V.　All　rights　reserved.