Preparation Of Novel Optical (electro) Catalytic Materials And Their Performance In Removing NOx

With the improvement of industrialization,the natural environment in China has been destroyed seriously.Recently,the fog haze weather appears frequently and PM 2.5 becomes more and more serious,Chinese government pays high attention to the air pollution.NO_x,as one of the air pollutants nitrogen oxides,can directly or indirectly cause serious harm to the environment and human.Due to the thermodynamic limit of the decomposition of NO_x at low temperature,the reaction speed is very slow,so it needs to develop an effective catalyst to reduce the activation energy,which can make the reaction go smoothly.Photocatalytic oxidation technology has advantages of removing nitrogen oxides with mild reaction conditions,low energy consumption,less secondary pollution,and the final product is easy to be absorbed by plants,microorganisms and other advantages,so it is considered to be environmentally friendly technology with a good prospect of application in the removal of NO_x.However,there are still some disadvantages such as low photocatalytic efficiency,low light utilization efficiency and easy deactivation of the catalysts,which seriously affect the application of photocatalysts in practice.Today,most of the catalysts are powder,the catalyst will be difficult to recover and easy to blow away in the gas reaction.Combinning with film catalysts and power catalysts,and using electro assisted photocatalysis technology to further improve the NO_x removal efficiency,the photocatalytic and Photoelectrocatalytic technology in environmental pollution control have a broad application prospect in technology.Therefore,the main research contents are as follows:1.Amino acid assisted synthesis of mesoporous multi-shelled ZnO microspheres and their enhanced photocatalytic activityMulti-shelled ZnO microspheres were synthesized by amino acid assisted synthesis by alcohol thermal method.By adjusting the thermal time of the reactor,the material was changed from solid to core shell,multi-shelled and then to hollow.The activity of NO_x removel was investigated by UV light,and the multi-shelled ZnO had the best removal activity.ZnO microspheres have a multi-shelled structure with large surface area,increasing the reactive sites and multiple reflection of light,so as to improve the utilization rate of light.2.Preparation of Free-standing film and its photocatalytic activity NO removalThe use of microwave and high concentration alkali solution synthesis of sodium titanate nanowires and carbon nanotubes doped composite materials,by pickling,argon tube furnace roasting to obtain carbon nanotube composite materials TiO₂ nanowires.After dispersed in aqueous solution and filtrated to the free-standing film material,it was used to oxide NO_x in photocatalysis.we adjusted the content of carbon nanotubes to get the optimal activity photoelectric film material.The problems such as the combination of photocatalysis and electrocatalysis and the difficulty of recovery are solved.3.Preparation of stainless steel substrate film and its photocatalytic activity NO removalThe use of microwave and high concentration alkali solution synthesis of sodium titanate nanowires and carbon nanotubes doped composite materials,by pickling,argon tube furnace roasting to obtain carbon nanotube composite materials TiO₂ nanowires.After dispersed in aqueous solution and filtrated to the stainless steel substrate film material,it was used to oxide NO_x in photocatalysis.The utility model not only solves the problem of the electrical conductivity of the material,greatly improves the conductivity and the activity,but also has the advantages of good flexibility and good stability.4.Preparation of g-C₃N₄ with high specific surface area by vacuum roasting method and its photocatalytic NO removalA method,the development of a vacuum roasting to get a material with large surface area,,not only avoids introduction of the other pollution in the process of vacuum roasting,but also can increase the surface area of the material.White curd precursor,which was obtained by using of melamine and cyanuric acid,was roasted in vacuum to obtain g-C₃N₄ material with 182 m2/g of large surface area.It combined with graphene get GO-g-C₃N₄ composites having good flexibility and visible light photocatalytic activity when filtrated on the stainless steel net.If it was used to removal of NO_x in photoelectric,the material would obtain very good removal effect.