Intermolecular proton-coupled electron transfer reconstructs aggregates for near-infrared-light-driven hydrogen evolution†

The construction of photosystems with strong near-infrared (NIR) light harvesting and efficient charge separation is key to achieving efficient solar energy utilization. Here, we report an approach to modulate the light capture capability and charge separation efficiency of 3-amino-1,2,4-triazine aggregates (denoted AT aggregates) by a proton-coupled electron transfer (PCET) process. DFT calculations and experimental results confirm that PCET-induced structural reconstruction can broaden the absorption range of AT aggregates from visible to NIR light. Meanwhile, the reconstructed AT aggregates have larger dipole moments, boosting charge delocalization and charge separation. Hence, the reconstructed AT aggregates show excellent photocatalytic performance for hydrogen production under NIR light. The quantum yield of the reconstructed AT aggregates reaches 1.23% at 850 nm, higher than most reported photosynthesis systems. The current research enriches the family of NIR-light-responsive photocatalysts and will also definitely motivate the design of unique aggregates as a new generation of photocatalysts for solar energy conversion.