Herein,　a　new　photocatalyst　(UiOS-Cu-CdS/ZnS,　abbreviated　as　SCu-CZS)　with　hierarchical　structure　is　well-designed　by　loading　CdS/ZnS　quantum　dots　(QDs)　onto　Cu　(II)　decorated　thiol-functionalized　UiO-66　(UiOS-Cu)　metal-organic　frameworks　(MOFs)　for　water　splitting,　where　CdS　and　ZnS　QDs　are　evenly　distributed　on　the　surface　and　in　the　channels　of　MOF,　respectively,　and　Cu　(II)　ions　are　connected　with　thiol　groups.　We　find　that　the　UiOS-Cu,　as　an　efficient　medium　for　the　separation　and　transfer　of　charge　carriers　between　CdS　and　ZnS,　successfully　transforms　the　I-type　transfer　mechanism　of　charge　carriers　in　CdS/ZnS　heterojunction　into　II-type　transfer　mechanism,　in　which　the　decoration　of　Cu　(II)　plays　a　key　role.　Due　to　the　decoration　of　Cu　(II),　the　highest　occupied　molecular　orbital　(HOMO)　of　UiOS-Cu　is　markedly　lifted　to　the　position　higher　than　the　valence　band　(VB)　of　CdS,　promoting　the　smooth　transfer　of　photoinduced　holes　from　the　VB　of　CdS　to　the　HOMO　of　UiOS-Cu.　Thanks　to　this　II-type　transfer　mechanism,　the　photogenerated　electrons　and　holes　are　effectively　separated　and　transferred,　significantly　improving　the　photocatalytic　H2　evolution　performance.　The　optimized　SCu-CZS　sample　exhibits　a　high　H2　generation　rate　of　425.5　μmol/h　(10　mg　of　catalyst)　with　an　apparent　quantum　efficiency　of　24.6%　at　the　wavelength　of　365　nm　in　the　absence　of　noble　metal　co-catalyst.　This　work　indicates　that　MOF　can　be　used　as　an　efficient　transfer　medium　of　charge　carriers,　promoting　photocatalytic　hydrogen　evolution　by　transforming　the　transfer　mechanism　of　photogenerated　electrons　and　holes,　which　provides　a　new　idea　for　the　construction　of　MOF-based　photocatalysts.　©　2020　Elsevier　B.V.