The Preparation And Optical Properties Study Of Modified TiO₂ Nanomaterials

TiO2, as an major inorganic functional material, has extremely broad application prospects in the solar energy storage, photocatalytic degradation of pollutants, the conversion from optics to electronics, etc.. However, a poor activity in visible light region and low quantum yield of Ti O2 have limitted its optoelectonic properties. Using non-metallic ions for doping Ti O2 can effectively improve the photoelectric activity. Therefore, in this paper, binary nonmetal ions(boron and nitrogen, boron and sulfur) doped Ti O2 will be intensively studied in the way of material sysnthesis, optical properties, photoelectric properties, and its application.Binary non-metal ions(B and N, B and S) codoped nano Ti O2 are prepared by controlled hydrolysis, and the influnence from binary non-metal ions on optical properties, phase, surface structure of samples are discussed. XRD spectra show that B/N and B/S doping do not cause change in the crystalline of Ti O2. The B-N bond and O-Ti-N bond in nano B/N/Ti O2, and O-Ti-B-O bond and O-Ti-S bond in nano B/S/Ti O2 measured by XPS indicate that Ti O2 lattice imperfection are formed, which could improve their photoelectric properties through effectively restraining the recombination of electron-hole pairs. UV-Vis spectra show that boron/nitrogen and boron/sulfur doping improve its absorption in visible light region, and promote its optical activity.The optical properties of nano B/N/TiO2 and B/S/Ti O2 are studied through applying them in the photocatalysis experiment. Experiment results show that pure Ti O2 has a extremely low degradation(almost 0%) to acid red 3R dye in the visible region, while B/N/Ti O2 and B/S/Ti O2 have quite high degradation(more than 96%), which is much higher than the pure Ti O2. The optimal conditions in solutions are identified. The results show that the p H value in soluions is affected by the number of sulfonic acid groups in degration, and the heating time is related to the doped non-metallic ion species through studing the effect of binary nonmetallic ions to photocatalysis experimental conditions.The photoelectric characteristic of nano B/N/Ti O2 and B/S/Ti O2 are verified in quantum sensitized solar cell, and the number of charge carriers and interfacial electron transfer mechanism are discussed. IPCE measurement indicates that binary non-metal doping broadens the absorption scope of light, and improves the number of charge carriers. Electrochemical impedance spectra(EIS) shows that the interface impendance between modified polysulfide electrolyte and Ni S counter electrode is very small, which efficiently improve the regeneration of modified polysulfide electrolyte in Ni S counter electrode interface, and accelerate the electron transport rate. Based on the analysis above, we have verification experiment for QDSC device, Whose conversion efficiency increase by 12% and 52%.