In　situ　photo-deposition　of　both　Pt　and　CoOx　cocatalysts　on　the　facets　of　poly　(triazine　imide)　(PTI)　crystals　has　been　developed　for　photocatalytic　overall　water　splitting.　However,　the　undesired　backward　reaction　(i.e.,　water　formation)　on　the　noble　Pt　surface　is　a　spontaneously　down-hill　process,　which　restricts　their　efficiency　to　run　the　overall　water　splitting　reaction.　Herein,　we　demonstrate　that　the　efficiency　for　photocatalytic　overall　water　splitting　could　be　largely　promoted　by　the　decoration　of　Rh/Cr2O3　and　CoOx　as　H-2　and　O-2　evolution　cocatalysts,　respectively.　Results　reveal　that　the　dual　cocatalysts　greatly　extract　charges　from　bulk　to　surface,　while　the　Rh/Cr2O3　cocatalyst　dramatically　restrains　the　backward　reaction,　achieving　an　apparent　quantum　efficiency　(AQE)　of　20.2　%　for　the　photocatalytic　overall　water　splitting　reaction.