Maneuvering Charge Transport via Insulating Polymer Interface for Steering Photoredox Catalysis.

Maneuvering precise and tunable charge transportation has remained the core issue of photocatalysis, but meets with limited success owing to the ultra-fast charge recombination rate, scarcity of applicable co-catalysts, and difficulty in customizing spatially separated carrier transport pathways. Although co-catalyst engineering affords a convenient strategy to dominate spatial charge migration to the ideal active sites, the conventional co-catalyst modification strategy fails to exquisitely mediate the interface between co-catalyst and semiconductor matrix, along with tedious synthesis procedures. Herein, an insulating polyelectrolyte (NCP), poly(diallyldimethylammonium chloride), is uniformly and seamlessly coated on the transition metal chalcogenides (TMCs) substrates via a facile electrostatic self-assembly approach and strategically serves as the highly efficient catalytic active sites for stimulating multifarious photoredox catalysis, including selective organic transformation and CO₂ reduction. The crucial roles of such NCP are unambiguously unraveled via comprehensive experimental and theoretical investigations, which include increasing reactant adsorption, providing active sites, and most importantly, boosting interfacial charge transfer rate. The electron-withdrawing capability of NCP fosters the effective charge separation over TMCs, leading to the concomitantly improved and stable photocatalytic activities toward aromatic nitro compounds reduction and CO₂-to-syngas conversion under visible light. Our work could strengthen our fundamental understanding of the generic unanticipated charge transport characteristics of insulating polymers for solar energy conversion.