Preparation Of Nitrogen-doped TiO₂ Sensitized By Eosin Y And Performance Of Photocatalytic Hydrogen Evolution Under Visible Light Irradiation

In this thesis the preparation and modification of TiO₂ visible light photocatalystsensitized by Eosin Y as well as its performance of photocatalytic hydrogen evolutionwas researched. The research works is composed of two parts:In the first part preparation of TiO₂ sensitized by Eosin Y and performance ofphotocatalytic hydrogen evolution under visible light irradiation was studied.TiO₂calcined at different temperatures were prepared by sol-gel method. Pt was loaded onTiO₂ photocatalyst by photodeposition method. Eosin Y was absorbed on Pt-TiO₂surface via impregnation method to prepare a series of dye-sensitization EosinY-Pt-TiO₂ visible light photocatalysts. The activity of the prepared photocatalystunder visible light irradiation was evaluated using photocatalytic hydrogen evolutionas a probe reaction. It is found that the activity of Eosin Y-Pt-TiO₂ calcined at 350℃is the best. Samples were characterized by XRD, BET, FT-IR and UV-Vis DRS. It isfound that the sensitization of Eosin Y extends the visible light response range ofTiO₂. Eosin Y makes TiO₂ have a very strong absorption from 400 nm to 600 nm.With calcination temperature decreasing, the specific surface area of TiO₂ increases,and the hydroxyl amount on the surface of TiO₂ also increases, so that with thetemperature decreasing, the adsorbed amount of Eosin Y also increases. Therefore thevisible light photocatalytic activity of Eosin Y-Pt-TiO₂ enhances accordingly.In the second part preparation and performance of nitrogen-doped TiO₂ sensitizedby Eosin Y for photocatalytic hydrogen evolution under visible light irradiation wasstudied. Pure TiO₂ and nitrogen-doped TiO₂ (N-TiO₂) calcined at low temperatureswere prepared using Ti(SO₄)₂ as precursor, NaOH solution and ammonia water asprecipitators respectively. Pt was loaded on the TiO₂, N-TiO₂ photocatalysts byphotodeposition method. Eosin Y was absorbed on Pt-TiO₂ and Pt-N-TiO₂ surfacesvia impregnation method to prepare two series of dye-sensitization photocatalystsEosin Y- Pt-TiO₂ and Eosin Y-Pt-N-TiO₂. The activity of the photocatalyst undervisible light irradiation was evaluated using photocatalytic hydrogen evolution as a probe reaction. It is found that when the calcined temperature is 300℃, the activitiesof both Eosin Y-Pt-TiO₂ and Eosin Y-Pt-N-TiO₂ are the best and the activity of EosinY-Pt-N-TiO₂ is about 3 times ofEosin Y-Pt-TiO₂. Samples were characterized byXRD, BET, FT-IR and UV-Vis DRS. It is found that the sensitization ofEosin Yextends the visible light response range of TiO₂ and N-TiO₂. Eosin Y makes TiO₂,N-TiO₂ have a very strong absorption from 400 nm to 600 nm. Doped nitrogen canrestrain the growth of crystal particle of TiO₂ and increase the specific surface area ofTiO₂, so that the adsorbed amount of Eosin Y also increases. Therefore the visiblelight photocatalytic activity of Eosin Y-Pt-N-TiO₂ enhances accordingly.