The lack of effective charge transfer driving force and channel limits the electron directional migration in nanoclusters (NC)-based heterostructures, resulting in poor photocatalytic performance. Herein, a Z-scheme NC-based heterojunction (Pt₁Ag₂₈-BTT/CoP, BTT = 1,3,5-benzenetrithiol) with strong internal electric field is constructed via interfacial Co–S bond, which exhibits an absolutely superiority in photocatalytic performance with 24.89 mmol·h⁻¹·g⁻¹ H₂ production rate, 25.77% apparent quantum yield at 420 nm, and ~ 100% activity retention in stability, compared with Pt₁Ag₂₈-BDT/CoP (BDT = 1,3-benzenedithiol), Ag₂₉-BDT/CoP, and CoP. The enhanced catalytic performance is contributed by the dual modulation strategy of inner core and outer shell of NC, wherein, the center Pt single atom doping regulates the band structure of NC to match well with CoP, builds internal electric field, and then drives photogenerated electrons steering; the accurate surface S modification promotes the formation of Co–S atomic-precise interface channel for further high-efficient Z-scheme charge directional migration. This work opens a new avenue for designing NC-based heterojunction with matchable band structure and valid interfacial charge transfer.

Metal nanoclusters (NCs) with precise structure and ultrasmall size have attracted great interests in catalysis. However, the poor stability has limited its large-scale use. Herein, we proposed the “covalence bridge” strategy to effectively connect atomically precise metal NCs and metal-organic frameworks. Benefiting from the covalent linkage, the synthesized UiO-66-NH₂-Au₂₅(L-Cys)₁₈ showed outstanding stability after 16 h photocatalysis. Moreover, the covalence bridge created a strong metal-support interaction between the two components and provided an effective charge transport channel and thereby enhanced photocatalytic activity. UiO-66-NH₂-Au₂₅(L-Cys)₁₈ displayed an exceptional photocatalytic H₂ production rate, which is 21 and 90 times higher than that of UiO-66-NH₂/Au₂₅(PET)₁₈ (made by physically combination) and bare UiO-66-NH₂, respectively. Thermodynamic and kinetic studies demonstrated that UiO-66-NH₂-Au₂₅(L-Cys)₁₈ exhibited higher charge transfer efficiency, lower overpotential of water reduction and activation energy barrier compared with its counterparts.