It　is　highly　desirable　but　challenging　to　optimize　the　structure　of　photocatalysts　at　the　atomic　scale　to　facilitate　the　separation　of　electron-hole　pairs　for　enhanced　performance.　Now,　a　highly　efficient　photocatalyst　is　formed　by　assembling　single　Pt　atoms　on　a　defective　TiO2　support　(Pt-1/def-TiO2).　Apart　from　being　proton　reduction　sites,　single　Pt　atoms　promote　the　neighboring　TiO2　units　to　generate　surface　oxygen　vacancies　and　form　a　Pt-O-Ti3+　atomic　interface.　Experimental　results　and　density　functional　theory　calculations　demonstrate　that　the　Pt-O-Ti3+　atomic　interface　effectively　facilitates　photogenerated　electrons　to　transfer　from　Ti3+　defective　sites　to　single　Pt　atoms,　thereby　enhancing　the　separation　of　electron-hole　pairs.　This　unique　structure　makes　Pt-1/def-TiO2　exhibit　a　record-level　photocatalytic　hydrogen　production　performance　with　an　unexpectedly　high　turnover　frequency　of　51423h(-1),　exceeding　the　Pt　nanoparticle　supported　TiO2　catalyst　by　a　factor　of　591.