Nitrogen-doped　TiO2-bronze@g-C3N4　(TiO2　(B)@g-C3N4)　two-dimensional　binary　heterojunctions　were　constructed　based　on　seeding-induced　growth　through　a　microwave-assisted　solvothermal　process　and　subsequent　thermal　treatment　in　a　vacuum.　The　morphology　of　the　TiO2　(B)　nanosheets　could　be　controlled　by　tuning　the　concentration　of　the　Ti　precursor,　which　determined　the　enhanced　photoelectron　activity.　The　optimal　photocatalytic　activity　for　the　degradation　of　methyl　orange　(MO)　under　low-intensity　visible-light　illumination　was　obtained　at　a　TiO2　(B)/g-C3N4　molar　ratio　of　1　:　1,　which　was　12.7　and　7.9　times　higher　than　that　of　pure　g-C3N4　and　P25,　respectively.　The　photocatalytic　activity　was　further　enhanced　by　about　7.7%　after　in　situ　N-doping.　The　improvement　in　photocatalytic　activity　of　N-doped　TiO2　(B)@g-C3N4　hetero-nanojunctions　was　attributable　to　the　strong　absorption　in　the　visible-light　region　and　better　separation　of　photogenerated　electron-hole　pairs　at　the　nanojunction　interface,　a　result　due　to　the　large　contact　area　between　N-doped　TiO2　(B)　and　g-C3N4　nanosheets.　We　have　explained　the　photocatalytic　degradation　of　MO　molecules　largely　in　terms　of　the　direct　oxidation　by　the　photogenerated　holes　and　partly　by　the　contribution　of　the　superoxide　radicals.