Artificial　photocatalytic　N-2　reduction　to　NH3　under　ambient　conditions　represents　a　promising　alternative　way　for　the　industrial　N-2　fixation　by　Haber　-　Bosch　process.　This　work　reports　the　simultaneous　engineering　of　BiOBr　nanosheets　with　exposed　{102}　facets　by　means　of　transition　metal　(Fe,　Mo,　Ni)　doping　and　oxygen　vacancies　(OVs)　that　aid　to　expose　internal　metal　dopants　toward　efficient　visible　light　N-2　fixation.　The　synergy　of　transition　metal　doping　and　OVs　results　in　the　modulated　band　structures,　improved　charge　carrier　separation　as　well　as　electron　transfer　to　N-2,　thereby　leading　to　enhanced　N-2　adsorption　and　activation　ability　over　modified　BiOBr　nanosheets.　In　particular,　the　Fe-doped　BiOBr　with　OVs　possesses　the　optimal　photocatalytic　activity　of　NH3　yield　of　46.1　mu　mol　g(-1)　h(-1)　without　any　sacrificial　agent,　which　is　6-fold　that　of　pristine　BiOBr.　The　findings　will　shed　new　light　on　rational　engineering　of　adsorption,　activation　sites　and　charge　carrier　separation　for　designing　efficient　N-2　fixation　photocatalysts.