The　design　of　metal-free　photocatalysts　has　drawn　considerable　attention　in　photocatalysis　due　to　the　merits　of　low　cost,　sustainability,　and　recyclability　without　releasing　toxic　metals　from　photocorrosion.　As　an　emerging　metal-free　photocatalyst,　the　covalent　triazine-based　framework　(CTF)　has　stimulated　great　research　interest　in　photochemical　water　splitting.　Nevertheless,　the　poor　separation　efficiency　of　photogenerated　charge　carriers　and　limited　light　absorption　ability　of　the　CTF　hinders　its　photocatalytic　performance.　Herein,　a　metal-free　2D/2D　heterostructured　photocatalyst　composed　of　black　phosphorus　(BP)　and　a　CTF　is　prepared　by　a　facile　liquid　exfoliation　approach　and　applied　to　photocatalytic　water　splitting　and　pollutant　degradation.　Compared　to　the　CTF,　the　BP/CTF　photocatalyst　exhibits　a　two-fold　increase　in　the　hydrogen　evolution　rate　and　a　nine-fold　increase　in　the　degradation　rate　constant　of　rhodamine　B　(RhB)　with　visible　light　illumination,　mainly　due　to　the　enhanced　photoinduced　charge　carrier　separation　and　strengthened　visible　light　harvesting　ability.　This　work　provides　sustainable　approaches　for　the　synthesis　and　construction　of　highly-reactive　and　metal-free　photocatalysts　for　solar-to-chemical　energy　conversion.　©　The　Royal　Society　of　Chemistry.