Photocatalytic　water　splitting　is　a　promising　method　for　hydrogen　production.　Numerous　efficient　photocatalysts　have　been　synthesized　and　utilized.　However,　photocatalysts　without　a　noble　metal　as　the　co-catalyst　have　been　rarely　reported.　Herein,　a　CoP　co-catalyst-modified　graphitic-C3N4　(g-C3N4/CoP)　is　investigated　for　photocatalytic　water　splitting　to　produce　H2.　The　g-C3N4/CoP　composite　is　synthesized　in　two　steps.　The　first　step　is　related　to　thermal　decomposition,　and　the　second　step　involves　an　electroless　plating　technique.　The　photocatalytic　activity　for　hydrogen　evolution　reactions　of　g-C3N4　is　distinctly　increased　by　loading　the　appropriate　amount　of　CoP　quantum　dots　(QDs).　Among　the　as-synthesized　samples,　the　optimized　one　(g-C3N4/CoP-4%)　shows　exceptional　photocatalytic　activity　as　compared　with　pristine　g-C3N4,　generating　H2　at　a　rate　of　936　μ　mol　g−1　h−1,　even　higher　than　that　of　g-C3N4　with　4　wt%　Pt　(665　μmol　g−1　h−1).　The　UV-visible　and　optical　absorption　behavior　confirms　that　g-C3N4　has　an　absorption　edge　at　451　nm,　but　after　being　composited　with　CoP,　g-C3N4/CoP-4%　has　an　absorption　edge　at　497　nm.　Furthermore,　photoluminescence　and　photocurrent　measurements　confirm　that　loading　CoP　QDs　to　pristine　g-C3N4　not　only　enhances　the　charge　separation,　but　also　improves　the　transfer　of　photogenerated　e−-h+　pairs,　thus　improving　the　photocatalytic　performance　of　the　catalyst　to　generate　H2.　This　work　demonstrates　a　feasible　strategy　for　the　synthesis　of　highly　efficient　metal　phosphide-loaded　g-C3N4　for　hydrogen　generation.　©　2020　Dalian　Institute　of　Chemical　Physics,　Chinese　Academy　of　Sciences