The　difficulty　of　adsorption　and　activation　of　CO2　at　the　catalytic　site　and　rapid　recombination　of　photogenerated　charge　carriers　severely　restrict　the　CO2　conversion　efficiency.　Here,　we　fabricate　a　novel　alkaline　Co(OH)2-decorated　ultrathin　2D　titanic　acid　nanosheet　(H2Ti6O13)　catalyst,　which　rationally　couples　the　structural　and　functional　merits　of　ultrathin　2D　supports　with　catalytically　active　Co　species.　Alkaline　Co(OH)2　beneficially　binds　and　activates　CO2　molecules,　while　monolayer　H2Ti6O13　acts　as　an　electron　relay　that　bridges　a　photosensitizer　with　Co(OH)2　catalytic　sites.　As　such,　photoexcited　charges　can　be　efficiently　channeled　from　light　absorbers　to　activated　CO2　molecules　through　the　ultrathin　hybrid　Co(OH)2/H2Ti6O13　composite,　thereby　producing　syngas　(CO/H2　mixture)　from　photoreduction　of　CO2.　High　evolution　rates　of　56.5　μmol　h-1　for　CO　and　59.3　μmol　h-1　for　H2　are　achieved　over　optimal　Co(OH)2/H2Ti6O13　by　visible　light　illumination.　In　addition,　the　CO/H2　ratio　can　be　facilely　tuned　from　1:1　to　1:2.4　by　changing　the　Co(OH)2　content,　thus　presenting　a　feasible　approach　to　controllably　synthesize　different　H2/CO　mixtures　for　target　applications.　©　2021　American　Chemical　Society.　All　rights　reserved.