Hydrogen Production System by Light-Induced α-FeOOH Coupled with Photoreduction.

Solar-driven catalysts on semiconductors to produce hydrogen are considered as a means to solve environmental issues. In this study, H production coupling with oxygen consumption by noble metal-free α-FeOOH was demonstrated even though the conduction band edge was lower than the reduction potential of H to H . For activation of α-FeOOH, an electron donor, Hg-Xe irradiation, and low pH (ca. 5) were indispensable factors. The H production from H O was confirmed by GC-MS using isotope-labeled water (D O) and deuterated methanol. The α-FeOOH synthesized by coprecipitation method showed 25 times more active than TiO . The photocatalytic activity was stable for over 400 h. Our study suggests that α-FeOOH known as rust can produce H by light induction.