A photosynthesis-inspired supramolecular system: caging photosensitizer and photocatalyst in apoferritin.

Inspired by the bioinorganic structure of natural [FeFe]-hydrogenase ([FeFe]-H2ase) that possesses iron sulfur clusters to catalyze proton reduction to hydrogen (H2), we design a supramolecular photosystem by sequentially integrating hydrophobic ruthenium complex (as a photosensitizer) and diiron dithiolate complex (as a photocatalyst) into the inner surface or cavity of apoferritin via noncovalent interactions. This platform allows photosensitizer and catalyst to localize in a close proximity and short-distance electron transfer process to occur within a confined space. The resulted uniform core-shell nanocomposites were stable and well dispersed in water, and showed enhanced H2 generation activity in acidic solution as compared to the homogenous system without apoferritin participation.