Visible-light-driven　N-2　reduction　into　NH3　in　pure　H2O　provides　an　energy-saving　alternative　to　the　Haber-Bosch　process　for　ammonia　synthesizing.　However,　the　thermodynamic　stability　of　N　equivalent　to　N　and　low　water　solubility　of　N-2　remain　the　key　bottlenecks.　Here,　we　propose　a　solution　by　developing　a　WO3-x　hollow　sphere　with　oxygen　vacancies.　Experimental　analysis　reveals　that　the　hollow　sphere　structure　greatly　promotes　the　enrichment　of　N-2　molecules　in　the　inner　cavity　and　facilitates　the　chemisorption　of　N-2　onto　WO3-x-HS.　The　outer　layer＇s　thin　shell　facilitates　the　photogenerated　charge　transfer　and　the　full　exposure　of　O　vacancies　as　active　sites.　O　vacancies　exposed　on　the　surface　accelerate　the　activation　of　N　equivalent　to　N　triple　bonds.　As　such,　the　optimized　catalyst　shows　a　NH3　generation　rate　of　140.08　mu　mol　g(-1)　h(-1),　which　is　7.94　times　higher　than　the　counterpart　WO3-bulk.