Photocatalysis using a Wide Range of the Visible Light Spectrum: Hydrogen Evolution from Doped AgGaS2

Doping of nickel into AgGaS2 yields a new absorption band, at a wavelength longer than the intrinsic absorption band of the AgGaS2 host. The doped nickel forms an electron donor level in a forbidden band of AgGaS2. The nickel-doped AgGaS2 with rhodium co-catalyst shows photocatalytic activity for sacrificial H-2 evolution under the light of up to 760 nm due to the transition from the electron donor level consisting of Ni2+ to the conduction band of AgGaS2. Apparent quantum yields for the sacrificial H-2 evolution at 540-620 nm are about 1%. Moreover, the nickel-doped AgGa0.75In0.25S2 also responds to near-IR light, up to 900 nm.