Overcoming　the　sluggish　kinetics　of　the　water　oxidation　is　the　key　to　a　high　performance　for　solar　water　splitting.　Herein,　phosphorylated　polymeric　carbon　nitride　(PCN)　photoanodes　were　developed　and　showed　enhanced　photocurrent　densities　for　solar　water　splitting.　A　photocatalytic　efficiency　of　120　μA　cm−2　was　achieved　in　the　basic　solution　(1.0　m　NaOH)　without　sacrificial　agents.　In　this　system,　phosphates　were　ionically　anchored　on　the　surface　of　PCN,　and　the　modified　films　showed　significantly　increased　density　of　valence　electrons,　and　thus　promoting　photocatalytic　efficiency.　©　2019　Wiley-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim