Hydrogen production by photocatalytic water-splitting using nitrogen and metal co-doped TiO2 powder photocatalyst

Nitrogen-doped titanium dioxide (N–TiO2) powders were synthesized by hydrolysis and used as a support for doping with various metals, such as, Fe, Cr, Ni, and Pt. Aqueous solutions of metal salts were used as a metal source and metals were deposited on N–TiO2 powders. Ni–N–TiO2 catalysts with various nickel concentrations were studied in detail. X-ray diffraction and diffuse reflectance spectrophotometry were used for the characterization of the photocatalysts. The Ni–N–TiO2 photocatalysts were then tested in photocatalytic water splitting under visible light. The optimum dopant concentration was found to be 10 μmol Ni/g N–TiO2 for Ni–N–TiO2. The photocatalyst, Ni–N–TiO2, has shown a stable and high activity, 490 μmol of H2 gcat−1 h−1 for the first 6 h of operation.