Atomic-Scale Charge Channelling in Poly(triazine imide) With Cooperative Ti-Ru Sites for Efficient Visible-Light CO₂...

Photocatalytic CO₂ reduction using H₂O as the electron donor provides a direct route for solar-to-chemical energy conversion, yet its efficiency is hindered by the lack of catalysts capable of directing charge flow and synchronizing redox kinetics. In this study, we report an atomic-scale charge-channelling strategy based on a spatially cooperative photocatalyst comprising Ti single atoms and Ru species anchored on crystalline poly(triazine imide) (PTI). Lattice-substituted Ti species introduce impurity levels that broaden visible-light absorption while serving as hole-extraction centers for H₂O oxidation, sustaining continuous hole flux. Concurrently, photogenerated electrons are funneled through the PTI framework to adjacent Ru sites, where CO₂ reduction to CO occurs. This cascade pathway establishes vectorial charge separation and kinetically couples the two half-reactions, effectively suppressing charge recombination. The optimized catalyst achieves a CO evolution rate of 281.0 µmol g^-1 h^-1 with excellent stability. Spectroscopic investigations combined with theoretical calculations reveal the complementary roles of Ti and Ru sites in regulating charge separation, carrier utilization and reaction energetics, while identifying the key reaction intermediates. This work provides mechanistic insight into spatially coupled charge transport and offers an effective strategy for the rational design of high-performance artificial photosynthetic systems.