A platinum-porphyrin zirconium metal-organic framework as an effective photocatalyst for hydrogen generation

Efficient solar energy storage via light-driven hydrogen (H₂) production presents a promising and attractive strategy for addressing the global energy crisis. The integration of platinum (Pt) co-catalyst into metal-organic frameworks (MOFs) to enhance photoinduced charge separation and transfer remains a significant challenge. Herein, a platinum-porphyrin zirconium metal-organic framework (MOF) PCN-223(Pt) is reported, and synthesized using a facile two-solvent strategy. The prepared PCN-223(Pt) is self-sensitized and contains a platinum (Pt) electron-trapping center, which confers excellent visible-light catalytic activity. Under visible-light irradiation, PCN-223(Pt) produced 732 micromol g^-1 h^-1 of H₂, a 7.6-fold increase compared to the isostructural PCN-223, which lacks Pt coordination in its porphyrin rings. This improvement results from the photogenerated electrons' efficient transport to the Pt electron-trapping centers, which improves charge carrier separation. Density functional theory calculations demonstrate the positive role that Pt in PCN-223(Pt) play in optimizing the corresponding hydrogen binding energy. PCN-223(Pt) exhibits excellent recyclability, maintaining its catalytic performance across five cycles without significant degradation. These results offer a new approach for designing MOF-based highly efficient visible-light active catalysts.