Photocatalytic　conversion　of　CO2　to　usable　fuel　precursors　is　one　of　the　most　important　renewable　paths　to　mitigate　energy　shortages　and　greenhouse　gas　emissions.　Photocatalysts　for　this　transformation　are　typically　based　on　precious　metals　to　obtain　high　yield　and　selectivity.　Currently,　metal-free　graphitic　conjugated　materials　(such　as　g-C3N4,　ternary　boron　carbon　nitride)　are　promising　and　emerging　photocatalysts　to　offset　the　above　issues.　Here　we　further　modulated　photocatalytic　performance　of　ternary　boron　carbon　nitride　(BCN)　by　introducing　fluorine　into　its　graphitic-like　framework.　As　a　result,　the　fluorination　of　the　BCN　productively　increases　the　CO　yield　by　three　times　under　visible　light.　It　was　found　that　fluorine　doping　can　remarkably　accelerate　migration-separation　efficiency　of　photogenerated　charge　carriers,　prolong　lifetime　of　the　excited　state　and　optimize　electronic　properties　of　BCN.