Photocatalytic Performance Of Titanium Dioxide Synthesized By Mesoporous Precursors For Water Splitting

Hydrogen, as a super-clean and environmentally-friendly energy resource with high heat of combustion, is expected to play a predominant role in the future's energy consumption structure. TiO₂ is a semiconductive catalytic material with good photocatalytic hydrogen production rate under UV light. After certain modification, such as incorporation of other elements or composition of other materials, its photocatalyticy properties can be expanded into the range of visible light. In the present work, a hydrothermal method was used to synthesize nanoparticles TiO₂-NP and then La, Co, Zr, Ni, Fe, N and S was introduced into the nanostructure to improve its properties; An m-TiO₂ with good photochemical activity was prepared by calcinating a mesoporous titanium dioxide precursor which was synthesized by a surfactant-assisted self-assembly method; The concerned synthesis and reaction conditions were optimized; Introduction of La and N made the material ?La-m-TiO₂ and N-m-TiO₂? sensitive to visible light; Composite material rG0/m-TiO₂ was synthesized by using hydrothermal method and evaluated in photocatalytic hydrogen-generation. The results show that:?1? Nanoparticle TiO₂-NP, as well as dopped nanoparticle samples M-TiO₂-NP and X-TiO₂-NP were synthesized by hydrothermal method. When the n_La/n_TiO2 was 0.01, the La-TiO₂-NP sample's hydrogen generation rate reached 3.85 L·g^-1h^-1 under UV light,20.3% higher than that of TiO₂-NP samples, and the hydrogen generation rate is 182 mL·g^-1h^-1 under visible light. When ns/n_TiO2 was 0.05, the S-TiO₂-NP sample showed the highest photocatalytic hydrogen generation rate of 3.90 L·g^-1h^-1 under UV light and 168 mL·g^-1h^-1 under visible light.?2? An m-TiO₂ with good photochemical activity was prepared by calcinating a mesoporous titanium dioxide precursor at 450?, the latter was synthesized by a surfactant-assisted self-assembly method. When m-TiO₂ amount was 0.4g/L, methanol concentration was 20% and Pt loading was 0.5-0.7wt%, the product showed the highest hydrogen generation rate (3.80 L·g^-1h^-1) under UV light. Its lifespan was as long as 20 hours, 1.54 times that of P25, and a total hydrogen generation 4.7% higher than that of P25. The dopped samples La-m-TiO₂ and N-m-TiO₂ were also synthesized by hydrothermal method. When n_La/n_TiO2 was 0.01, the La-m-TiO₂ sample's hydrogen generation rate reached 4.45 L·g^-1h^-1 under UV light, which is 17% higher than non-composite sample, and the hydrogen generation rate was 137 mL·g^-1h^-1 under visible light. When nN/n_TiO2 was 4, the N-m-TiO₂ sample's hydrogen generation rate was 4.50 L·g^-1h^-1 under UV light, showing an increase of 18% in comparison to non-composite sample. Under visible light, its hydrogen generation rate was 164 mL·g^-1h^-1.?3? A rGO/m-TiO₂ sample was synthesized by using hydrothermal method. When n_TGO/n_TiO2 was 0.01, the sample's hydrogen production rate was 5.4L·g^-1h^-1 under UV light, 42% higher than that of non-composite material; under visible light, its hydrogen production rate reached a maximum of 196 mL·g^-1h^-1.