Site-selective　deposition　of　dual　cocatalysts　for　H2　and　O2　evolution　reactions　on　polymeric　carbon　nitride　(PCN)　nanosheets　still　remains　a　great　challenge　due　to　the　difficulty　in　controlling　the　nucleation　location　and　growth　dynamics.　Herein,　we　report　an　one-step　and　efficient　photodeposition　strategy　to　simultaneously　load　Rh　and　RhOx　nanoparticles　on　PCN　nanosheets　with　desired　spatial　isolation.　The　dual　cocatalysts　modification　can　effectively　accelerate　the　reaction　kinetics　and　boost　the　separation　of　photoinduced　charge　carriers,　greatly　enhancing　overall　water　photosplitting　efficiency.　As　a　result,　the　overall　water　photosplitting　activity　of　Rh-RhOx/PCN　is　obviously　higher　than　those　of　RhOx/PCN　and　Rh/PCN.　This　work　provides　a　new　method　for　loading　dual　cocatalysts　on　the　PCN　nanosheets　with　spatial　isolation　to　achieve　pure　water　splitting　under　visible　light　and　offers　promise　for　a　wealth　of　innovative　applications　in　energy　conversion,　catalysis　and　environmental　protection.　©　2019　Elsevier　Inc.