Porphyrin metallacage-based host-guest complexation for highly efficient photocatalytic hydrogen production

Photocatalytic hydrogen evolution is a promising method for sustainable fuel production, but the efficiency of metal-organic complexes (MOCs) as photocatalysts is often limited by their poor light absorption, rapid exciton recombination, and aggregation. To address these challenges, we encapsulated Pt-based MOCs within porphyrin-based metallacages, which not only prevent the aggregation of catalysts but also enable effective electron transfer from the photosensitive metallacages to the photocatalysts. The structures of the host-guest complexes were confirmed by single-crystal X-ray diffraction, and one complex achieved a hydrogen generation rate of 19,786.5 µmol g⁻¹ h⁻¹, which was among the highest values in metallacage-based photocatalytic systems. Femtosecond transient absorption and DFT calculations revealed that the enhanced performance is due to efficient photoinduced electron transfer from the porphyrin units to the Pt catalytic centers. This work demonstrates a new approach to integrating photosensitizers and photocatalysts via host-guest complexation, offering an effective pathway to improve photocatalytic hydrogen production.