Enhanced photocatalytic hydrogen evolution by combining water soluble graphene with cobalt salts.

There is tremendous effort put in the pursuit for cheap and efficient catalysts for photocatalytic hydrogen evolution systems. Herein, we report an active catalyst that uses the earth-abundant element cobalt and water-dispersible sulfonated graphene. The photocatalytic hydrogen evolution activity of the catalyst was tested by using triethanolamine (TEOA) as electron donor and eosin Y (EY) as the photosensitizer under LED irradiation at 525 nm. Hydrogen was produced constantly even after 20 h, and the turnover number (TON) reached 148 (H2/Co) in 4 h with respect to the initial concentration of the added cobalt salts was shown to be 5.6 times larger than that without graphene.