Preparation And Photocatalytic Performance Research Of Neodymium-doped TiO₂ Nanomaterials

The rapid development of science and technology and the economy has brought about a series of increasingly serious environmental pollution problems.Some common and often mentioned pollution include air pollution and water pollution.All these restrict the sustainable development of mankind.Therefore,on the one hand,it is necessary to control the discharge of pollutants in industrial production from the source,and on the other hand to control the discharged pollutants,these actions need to be carried out immediately.Among the many materials that treat environmental pollution,photocatalytic materials are favored for their unique properties such as clean and pollution-free,and rapid degradation.Among the photocatalytic materials with semiconductor oxides as catalysts,titanium dioxide has become a photocatalytic material with its excellent properties.However,the photocatalytic technology based on titanium dioxide semiconductors also has the disadvantages of low quantum efficiency and excessively large band gap,which greatly restrict the widespread application of photocatalysts.Aiming at the above problems,in order to make the titanium dioxide photocatalyst widely used and popularized in the industry,and to improve the photocatalytic activity of titanium dioxide under visible light,to improve the solar energy utilization rate and the stability of new photocatalytic materials,this subject is a composite modification of titanium dioxide.Using rare earth element neodymium as doping element,two different types of neodymium-doped titanium dioxide were prepared by sol-gel method and co-precipitation-hydrothermal method.The main research contents are as follows:?1?TiO₂ particles were prepared by sol-gel method,and tetrabutyl titanate was used as a titanium source.The effects of solution p H,ultrasonic temperature,and calcination temperature on the preparation of nano-titanium dioxide were studied by orthogonal experiments,and the experiments were analyzed simultaneously.The photocatalytic test results show that when the p H is controlled to 2,t he ultrasonic temperature is 40?,the calcination temperature is 450?,and the calcination time is 4 hours,the morphology and photocatalytic performance of the prepared nano titanium dioxide are the best.Under simulated sunlight conditions,the degradation is 46.8% in 120 minutes.?2?On the basis of?1?,nanometer-sized neodymium-doped titanium dioxide nanoparticles were prepared by the same sol-gel method.The effect of the amount of doping on the degradation of the samples in the organic dye methyl orange was determined by photocatalysis experiments after the sample was doped with rare earth elements.Through physical characterization,the morphology,structure,crystal type,particle size and chemical elements of the sample were tested.The experimental results show that: under the optimal process parameters of?1?,the sample with the best photocatalytic performance has a neodymium doping amount of 1 mol%,which degrades the methyl orange solution under ultraviolet light within 60 minutes,and the degradation is 98%;Under simulated sunlight 's irradiation in 120 minutes,the degradation is 96.5%.The XRD analysis results show that the prepared titanium dioxide crystal form is anatase mixed with rutile,and the titanium dioxide doped with neodymium appears as pure anatase;SEM and TEM images of the sample s how that pure titanium dioxide nanoparticles with 10 nm size,the doped sample has a larger neodymium grain size,which makes the sample size between 3-5 ?m.?3?The coprecipitation-hydrothermal method was used,with titanium sulfate as the titanium source,and co-precipitated with lithium hydroxide solution to generate a titanium hydroxide precursor.A lithium hydroxide solution was added in the hydrothermal stage to prepare a titanium dioxide nanosphere matrix.The structure of titanium dioxide nanospheres is controlled in the range of 10-20 nm.At the same time,in order to obtain a catalyst with better photocatalytic performance,neodymium-doped titanium dioxide was prepared using neodymium nitrate as the neodymium source in the hydrothermal stage.The effect of the amount of neodymium on the photocatalytic effect of the final product was studied by a controlled variable method.The experimental results show that when the doping amount of neodymium is 1: 100 in the molar ratio of neodymium to titanium,that is,the doping amount is 1 mol%,the final prepared neodymium-doped titanium dioxide has the best photocatalytic performance: under ultraviolet light the degradation of methyl orange solution is 98.2% in 60 minutes;under simulated sunlight,the degradation is 99.14% in 120 minutes.And the samples were analyzed by physical characterization methods for crystal form,grain size,micro-morphology and elements.The XRD analysis results show that the crystal form of the prepared sample is a mixed phase of anatase and TiO₂-B phase,that is,the crystal form of the sample is not changed by doping.