Photocatalytic　reduction　of　CO2into　availableorganic　compounds　has　received　remarkable　attention.　However,photocatalytic　CO2reduction　is　limited　to　meet　industrialapplication　requirements　because　of　the　lack　of　effective　photo-catalysts.　Surface　frustrated　Lewis　pairs　(FLP)　are　found　inbismuth　oxybromide　(BiOBr),　which　are　effective　catalytic　sites　toactivate　and　photocatalytically　reduce　CO2.　Furthermore,　theintroduction　of　Ce4+and　oxygen　vacancy　can　optimize　both　theelectronic　state　and　the　FLP　property　of　BiOBr.　The　combinedexperimental　and　theoretical　characterizations　reveal　that　Ce4+andO2-can　form　the　frustrated　Lewis　acid-base　pairs,　which　cancatch,　excite,　and　reduce　CO2into　CO　at　a　high　yield　of　50.9　mu　Lh-1,　being　9.8　times　as　large　as　pristine　BiOBr.　This　work　illustratesa　rational　strategy　for　both　construction　of　highly　efficientphotocatalysts　and　insights　into　the　photocatalytic　mechanism　at　the　atomic　level.