The photodecomposition of NH3 to H-2 and N-2 was carried out by using Pt-supported metal-doped TiO2 (Pt/M-TiO2, M: dopant element) photocatalyst in an aqueous NH3 solution under UV irradiation at room temperature. Fe-doped TiO2 photocatalysts (Pt/Fe-TiO2) promoted the highest yield of H-2 formation in the NH3 photodecomposition. UV-visible diffuse reflectance spectra of Fe-doped TiO2 showed that the absorption edge of TiO2 was shifted from the ultraviolet to the visible light region by substitution with Fe. In addition, X-ray diffraction and electron spin resonance spectra showed that the dopant metals substituted a portion of the Ti4+ sites in the TiO2 crystal without changing TiO2 structure. Hence, it is indicated that TiO2 doped with Fe can utilize visible light wavelengths and effectively produce hydrogen from the decomposition of aqueous NH3. (C) 2014 Elsevier B.V. All rights reserved,