Designing　efficient　photocatalysts　for　photocatalysis　hydrogen　production　is　crucial　for　advancing　green　energy　technologies.　In　this　work,　ZnIn2S4　photocatalyst　with　an　asymmetric　Zn-Zn-S　unit　ring　structure　and　abundant　in　S　vacancies　was　achieved　by　precisely　tuning　the　molar　mass　of　the　Zn　ion　source　using　ethylene　glycol　as　the　reaction　solvent.　Z-type　heterojunction　was　constructed　via　the　electrostatic　assembly　by　combining　silver　clusters　(Agx@GSH)　with　ZnIn2S4　to　enhance　charge　separation　and　photocatalytic　activity.　The　structural　transition　from　S-Zn-S　to　Zn-Zn-S　led　to　local　charge　redistribution.　Meanwhile,　S　vacancies　acted　as　electron　traps,　promoting　the　charge　state　change　of　S　in　the　S[sbnd]H　sites　and　significantly　accelerates　the　hydrogen　evolution　reaction　(HER).　The　composite　catalyst　Zn-Vₛ-ZIS/Agx@GSH　exhibited　a　hydrogen　production　rate　of　18.4　mmol·g−1·h−1,　under　acidic　conditions　with　lactic　acid　as　the　sacrificial　agent,　which　is　3.7　times　higher　than　pristine　ZnIn2S4.　Density　functional　theory　(DFT)　calculations　revealed　that　the　Zn-Zn-S　distortion　and　heterojunction　formation　synergistically　enhanced　charge　transfer　and　hydrogen　adsorption　kinetics.　This　work　provides　a　novel　approach　for　tailoring　ZnIn2S4-based　photocatalysts　and　provides　new　insights　into　the　design　of　high-performance　heterojunction　systems　for　solar　energy　conversion.　©　2025