Hydrogen Production by Selective Photo-dissociation of Water in Aqueous Colloidal Nano-particles of Doped Iron (III) Oxides Semiconductors

Homogenous and heterogeneous production of hydrogen via photo-dissociation of water has been achieved with visible range solar radiation without any external potential at room temperature. Potassium ferrocyanide as a solvated-electron supplier and electron exchanger in basic buffers was used as a homogenous media for hydrogen production. Aqueous colloidal solutions of p-type Fe2O3 doped with MgO (Fe1.8Mg0.2O3) or with ZnO (Fe1.9Zn0.1O3) suspensions in ferrocyanide solutions were used as heterogeneous media for hydrogen generation by reduction of ferricyanide. The effects of the hole-scavengers such as oxo-anions and solvated-electron- suppliers were investigated. Results showed that Fe2O3 doped with ZnO was more efficient than that doped with MgO. The studies also showed that the aqueous nano-systems we used retained their stability as indicated by the reproducibility of their photocatalytic activities. Solar radiated assemblies of doped Fe2O3/[Fe(CN)6]−4 sustained cyclic systems for continuous hydrogen production.