Self-Healing of Molecular Catalyst and Photosensitizer on Metal-Organic Framework: Robust Molecular System for Photocatalytic H2 Evolution from Water

Inspired by self-repair mechanism of PSII in plants, we report a self-healing system which spontaneously repairs molecular catalyst and photosensitizer during photocatalytic H-2 evolution. A bipyridine-embedded UiO-type metal-organic framework (MOF), namely Pt-n_Ir_BUiO, which incorporated H-2-evolving catalyst and photosensitizer, was synthesized and subject to photo catalytic H2 evolution reaction (HER). Impressively, HER with Pt-0.1_Ir_BUiO showed very stable molecular photo catalysis without significant decrease in its activity and colloidal formation for 6.5 days at least; in the homogeneous counterpart, the molecular catalyst became a colloid just after 7.5 h. It was revealed that the arrangement of diimine sites which closely and densely surrounded the H-2-evolving catalyst and photosensitizer in the MOF enabled such a highly efficient self-healing.