Photocatalytic　N2　reduction　using　H2O　to　produce　NH3　offers　a　promising　alternative　to　the　energy-intensive　Haber-Bosch　process.　Nevertheless,　its　efficiency　is　hampered　by　the　low　solubility　of　N2　in　water,　the　high　stability　of　N---N　and　the　competing　H2　evolution　reaction　(HER).　In　this　study,　we　present　a　highly　efficient　nanohybrid　system　employing　BiOBr　nanoflowers　with　O　defect　as　a　platform　for　anchoring　Ru.　The　designed　nanohybrids　exhibit　a　significantly　higher　NH3　generation　rate　of　121.97　mu　mol　g-1　h-1,　which　is　6.1　and　2.8　times　higher　than　that　of　pristine　BiOBr-NS　and　Ru　modified　BiOBr　without　O　defect,　respectively.　Experimental　analyses　and　theoretical　calculations　reveal　that　the　nanoflower　structure　with　confined　nano-space　promotes　the　enrichment　of　N2　on　the　catalyst,　the　synergistic　O　defects　and　Ru　facilitate　the　selective　adsorption　and　activation　of　N2　and　lower　the　energy　barriers　of　the　rate-determining　*N-N　to　*N-NH　step.