Abstract:

Nitrogen doped SrTiO3 was prepared by solid phase method, and NiO(CoO)/N-SrTiO₃ heterojunction complex catalysts with different NiO or CoO loading contents were further obtained via impregnation-hydrogen reduction method. The as-obtained photocatalysts were characterized by XRD, SEM, UV-Vis DRS and Fluorescence spectrum techniques. The photocatalytic hydrogen generation activity and the variation laws under simulated sunlight irradiation were investigated. The effect of different treatment methods of loading NiO on hydrogen generation activity of nitrogen doped SrTiO₃ was also studied. The results demonstrate that the photocatalytic activity of the oxides loaded complex catalyst treated by hydrogen reduction firstly and then oxidation is higher than that of the oxides loaded complex catalyst treated by direct oxidation. Comparing with the single catalysts, the asprepared NiO/N-SrTiO₃, CoO/N-SrTiO₃ complex photocatalysts exhibit higher photocatalytic hydrogen generation activity under simulated sunlight irradiation. The optimal photocatalytic activity of hydrogen production is achieved when the loaded mass percentage is 1.0wt%, 0.5wt% respectively and the amount of hydrogen within 6h is 4.2, 4.9 times more than that of unloaded samples. The reason is that the heterojunction structure formed at the interface of two phases can act as the convenient unilateralism channel for the transfer of photogenerated electrons and holes in the process of photocatalytic reaction after loading the metal oxides, leading to the effective separation of photogenerated carriers, so as to enhance the photocatalytic activity of catalysts.

Key words: N-SrTiO₃, load, heterojunction, simulated light, hydrogen production