UV-driven overall water splitting using unsupported gold nanoparticles as photocatalysts

We confirmed that Au nanoparticles (> 10 nm) exhibit photocatalytic overall water splitting into H-2 and O-2 simultaneously with a ratio close to 2 : 1 without the assistance of sacrificial electron donors and cocatalysts under UV illumination for the first time. The hydrogen production rate of 5.7 mu mol g(-1) h(-1) in pure water was achieved, which is higher than that of TiO2 nanoparticles (P25, 1.2 mu mol g(-1) h(-1)). The interband transitions from 5d (valence band) to 6sp (conduction band) are responsible for this photocatalytic activity over Au nanoparticles.