Abstract: Combining organic photosensitive center with dinuclear-metal catalytic center through covalent bonds to synthesize supramolecular catalysts for photocatalytic hydrogen evolution is a cost-efficient approach to convert solar to hydrogen energy, while it has been rarely explored. Herein, we constructed a self-photosensitizing pyrene-decorated dinuclear cobalt(II) molecular photocatalyst [Co₂(pyrene-L)₂] via covalent bonds, which can accelerate photogenerated electron transfer from pyrene center to dinuclear cobalt(II) center, achieving efficiently photocatalytic hydrogen evolution in the absence of any noble metal photosensitizers. The photocatalytic activity of Co₂(pyrene-L)₂ is more than 3-fold over that of the physically mixed sample. Moreover, owing to the synergistic effect of dinuclear cobalt(II) centers, the activity of Co₂(pyrene-L)₂ is 10-fold higher than that of mononuclear counterpart (Co(pyrene-L)₂). As the first example of self-photosensitizing pyrene-decorated dinuclear metal molecular catalyst, it not only features multi-functions of photosensitivity, photoreduction and photooxidation, but also possesses synergistic dinuclear metal centers to improve catalytic activity, which gives new insights for researchers in designing high-performance photocatalysts for hydrogen evolution.

Key words: Dinuclear metal complex, Photocatalytic hydrogen evolution, Synergistic catalysis, Self-photosensitizing, Pyrene