Rapid Interchain Charge Transfer via Intra-macromolecular Hydrogen Bond Interactions Promotes Photocatalytic Hydrogen Production

Efficient electron transfer between photosensitizers (PS) and catalysts is essential for improving the photocatalytic performance of multicomponent systems. In conventional homogeneous catalytic systems, electron transfer typically occurs through random collisions, which are inherently inefficient. While various strategies have been proposed to enhance this process, many are limited by their dependence on high concentrations. Here, we reported a new strategy that significantly enhanced visible-light-driven hydrogen evolution reactions (HER) under low-concentration conditions for non-noble-metal-complex-based homogeneous systems. By employing RAFT polymerization, we immobilized copper PS (Cu-PS) and cobalt catalyst (Co-Cat) units on a carbamate-linkage-containing polymer chain. The introduction of carbamate linkages in the pendant chains closes the distance between the center of Cu-PS and Co-Cat by additional H-bond interactions, enabling high photocatalytic activity at low concentrations. Comparative analysis showed that the carbamate-linkage-containing polymeric complexes demonstrate a 20-fold hydrogen production over their non-H-bond polymeric complex, while no hydrogen was produced when using their small molecular counterparts in 24 h. This work underscores the superiority of the H-bond-containing polymeric complexes in photocatalytic activities. Given the versatility of RAFT polymerization and the ease of ligand modification, this method offers broad applicability across multicomponent photocatalytic systems.