Substituent Effect to Fine‐Tune Energy Levels of Atom‐Precise [MoOS3]2− Modified Copper(I) Thiolate Clusters Boosting Recyclable Photocatalysis

The propulsion of photocatalytic hydrogen (H₂ ) production is limited by the rational design and regulation of catalysts with precise structures and excellent activities. In this work, the [MoOS₃ ]^2- unit is introduced into the Cu^I clusters to form a series of atomically-precise Mo^VI -Cu^I bimetallic clusters of [Cu₆ (MoOS₃ )₂ (C₆ H₅ (CH₂ )S)₂ (P(C₆ H₄ -R)₃ )₄ ] ⋅ xCH₃ CN (R=H, CH₃ , or F), which show high photocatalytic H₂ evolution activities and excellent stability. By electron push-pull effects of the surface ligand, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels of these Mo^VI -Cu^I clusters can be finely tuned, promoting the resultant visible-light-driven H₂ evolution performance. Furthermore, Mo^VI -Cu^I clusters loaded onto the surface of magnetic Fe₃ O₄ carriers significantly reduced the loss of catalysts in the collection process, efficiently addressing the recycling issues of such small cluster-based catalyst. This work not only highlights a competitively universal approach on the design of high-efficiency cluster photocatalysts for energy conversion, but also makes it feasible to manipulate the catalytic performance of clusters through a rational substituent strategy.