Cobalt-based　materials　are　promising　cocatalysts　applied　to　polymeric　carbon　nitride　(PCN)　photocatalysts　to　achieve　water　oxidation　due　to　their　cost-effectiveness　and　comparable　activity　to　Ru　and　Ir-based　metal　oxides.　In　this　study,　by　optimizing　the　electron　configuration　of　cobalt-based　materials,　a　novel　oxygen　evolution　cocatalyst,　cobalt　disulfide　(CoS2),　was　developed　to　hybridize　with　PCN.　A　series　of　experimental　and　theoretical　studies　reveal　that　loading　CoS2　on　PCN　contributes　to　improving　photoinduced　charge　carrier　transportation　and　reducing　activation　energy　of　the　oxygen　evolution　reaction,　thus　achieving　a　significantly　enhanced　photocatalytic　performance　than　the　pure　PCN.　Furthermore,　due　to　the　more　satisfactory　electronic　configuration　of　CoS2,　the　photocatalytic　oxygen　evolution　rate　of　CoS2/CNNS　hybrid　is　even　more　than　1　time　higher　than　that　of　Co3O4/CNNS　hybrid.　©　2025　Wiley-VCH　GmbH.