Preparation And Performance Evaluation Of Full Spectrum Response To Titanium Based Photocatalytic Materials

Current environmental pollution and energy consumption are the biggest problems that plague people's lives.How to effectively use energy,increase energy efficiency,and use non-fossil fuel energy are the best solutions to these problems.Among them,solar energy is the cleanest,environmentally friendly and safe energy source.The sunlight is composed of 45%visible light,50%infrared light and 5%ultraviolet light,so the use of visible light and long-wavelength infrared light is very critical.If a new type of nano-functional material with full-wavelength light response can be prepared,the efficient use of clean energy by sunlight can be fully realized.TiO₂ and SrTiO₃ are semiconductors with wide bandgap and can only beexcited by ultraviolet light,so they need to be modified to extend the spectral response to the visible light region.The up-conversion material is a luminescent material that can convert low-energy light into high-energy light,which increases the possibility of full spectrum utilization of sunlight.In this paper,rare-earth ions,nitrogen and fluorine co-doped Ti O₂ were prepared by solvothermal method,and the photoresponse of SrTiO₃ was improved by metal plasma resonance.On the basis of this,these composite materials were prepared by up-conversion material and Ti O₂,SrTi O₃,and the ability of the composite materials was studied.This paper mainly includes the following three aspects:?1?TiO₂ photocatalyst doped with rare earth elements were prepared by solvothermal method.The effects were investigated under different factors including different rare earth elements,non-metal N,F doping ratios,and solvothermal reaction temperature.The results showed the optimal reaction conditions is 2wt%of La,N:F=1:1,160°C.And the band gap of La-TONF is2.67 eV,the visible light absorption margin is 464 nm.At the same time,the photoelectric signal intensity is strong.After 3 hours of visible light irradiation,the degradation rate of the methyl orange solution can reach 90.6%,which is 4.4times that of the pure TiO₂.The sample is recycled 5 times and the degradation rate is kept above 85%.?2?Cr-SrTiO₃ and Ag/Cr-SrTiO₃ photocatalytic materials were prepared by solvothermal method.The effects were investigated under different factors including Cr doping amount,Ag doping amount,surfactant type,solvothermal reaction temperature,and silver halide.It was found that the optimal reaction conditions is 3%of Cr,4wt.%of Ag,160°C,oleic acid.On this basis,the best absorption of the sample Ag/Cr-SrTiO₃ was obtained.At the same time,the photoelectric signal intensity is strong.Under the condition of pH=2 and H₂O₂,the degradation rate of methyl orange solution is 98.8%,which is 1.38 times that of pure SrTiO₃.The degradation rate of AgCl/Cr-SrTiO₃ is 97.1%,which is 1.35times that of pure SrTiO₃.?3?The composite materials of three kinds of up-conversion materials and titanium-based catalysts were prepared by solvothermal method.The luminescent and photocatalytic properties of these composite materials were studied.It was found that the composite materials could be excited by ultraviolet,visible and near-infrared light,so the full-spectrum absorption of sunlight is achieved.When NIR lights are irradiated to the composites,the up-conversion phosphor would be excited,and then blue,green or red lights are emitted.The emitted visible lights could be absorbed by La-TONF and Ag/Cr-SrTi O₃ in the composites.?1:1?@G-UP/La-TONF and?1:1?@G-UP/Ag/Cr-SrTiO₃ still exhibited the strongest emission intensity.The composite materials showed good near-infrared light-induced photocatalytic degradation of methyl orange dye in solution.The photocatalytic degradation rate of?1:1?@B-UP/La-TONF is 16.5%undernear-infraredlightirradiation.Thedegradationrateof?1:1?@B-UP/Ag/Cr-SrTiO₃ is 26.3%under near-infrared light irradiation,pH=2and H₂O₂.