Eosin Y-sensitized nitrogen-doped TiO2 for efficient visible light photocatalytic hydrogen evolution

A nitrogen-doped TiO2 (N-TiO2) photocatalyst was prepared by the calcination of the hydrolysis product of Ti(SO4)2 with aqueous ammonia. Pt was loaded on N-TiO2 by photodeposition method. A dye-sensitization photocatalyst was prepared by impregnation method with Eosin Y and the platinized N-TiO2. The prepared samples were characterized by XRD, UV–vis diffuse reflectance spectra (DRS), BET and FT-IR. The visible light activity of the sensitization photocatalysts was evaluated by photocatalytic hydrogen evolution (λ > 420 nm) in the presence of electron donor triethanolamine (TEOA). The N-TiO2 has smaller crystalline size and larger specific surface area to enhance the adsorption amount of Eosin Y than TiO2 prepared by NaOH. Surface oxygen defects produced by nitrogen doping would improve the adsorption of Eosin Y and excited electron to transfer to the conduction band of N-TiO2. Therefore the visible light activity of the sensitized nitrogen-doped platinized TiO2 is much higher than that of the sensitized platinized TiO2. The sensitized nitrogen-doped platinized TiO2 calcined at 300 °C has the highest visible light activity among the catalysts calcined at various temperatures, whose activity is increased by a factor of 3 compared to that of the sensitized platinized TiO2 calcined at the same temperature.

Graphical abstractThe Eosin Y-sensitized platinized nitrogen-doped TiO2 photocatalyst with high visible light activity was prepared. The sensitization of Eosin Y extends the visible light response range of N-TiO2. The N-TiO2 has smaller crystalline size and larger specific surface area to enhance the adsorption amount of Eosin Y than TiO2 prepared by NaOH. In particular, the surface oxygen defects produced by nitrogen doping would improve adsorption of Eosin Y at the catalyst and excited electron to transfer to the conduction band of N-TiO2. Therefore the photocatalytic activity of Eosin Y-Pt-N-TiO2 is much higher than that of Eosin Y-Pt-TiO2. On the optimum conditions, the activity of Eosin Y-Pt-N-TiO2-300 °C is enhanced by a factor 3 compared to that of Eosin Y-Pt-TiO2-300 °C. Figure optionsDownload full-size imageDownload as PowerPoint slide