Synthesis And Application In Energy Catalysis And Separation Of Functional Oxide Porous Materials

With the increasingly serious environmental damage and energy crisis,how to develop green,sustainable and clean energy to meet the needs of human society for energy has become a problem worthy of every researcher's consideration.In order to solve the serious problem of energy crisis and environmental damage,we should start from two aspects:one is to develop and use green and environment-friendly new energy;on the other hand,under the existing conditions,we should minimize the use of fossil energy and treat the environmental pollution caused by the use of fossil fuel.Functional Gradient ordered porous materials have a wide range of applications in catalysis,separation,batteries,thermal insulation,fuel and other fields.For example,in the field of catalysis,The structure and composition of the porous with ladder nature can provide more attachment points for the catalyst,which can greatly improve the catalytic performance of the catalyst,so hydrogen can be produced on a large scale with high efficiency.and in the field of industrial separation.the application of functional porous membrane materials is more extensive,special The pore structure can provide high throughput for the entire separation process to greatly improve the separation efficiency,excellent oil-water separation performance is also of great significance to the treatment of original pollution.In this paper,the application of functional porous materials in photo-assisted electrocatalytic hydrogen production and oil-water separation was studied in depth.Among hydrogen evolution reaction(HER)electrocatalysts,noble met.al electrocatalysts have high catalytic activity.However,precious met.als have limitations of low reserves and high costs.Moreover,the energy consumed by the water electrolysis hydrogen production process is twice the theoretical value of water splitting,which makes the energy consumption cost of hydrogen production relatively high.The above two reasons limit the large-scale industrial application of hydrogen production by electrolysis of water.Photosplitting water can also produce high-purity hydrogen,and only need light to generate hydrogen without additional energy consumption.However,the hydrogen production rate of photocatalytic hydrogen production is low,it is difficult to meet the industrial demand for large-scale hydrogen production.Electrolyzed water and photolyzed water each have their own limitations,but the combination of photolyzed water and electrolyzed water can reduce the overpotential of the electrocatalytic hydrogen evolution reaction and save electricity.Therefore,the research on photosensitive oxygen evolution and hydrogen evolution catalysts with low cost,high activity and high stability has received extensive attention from researchers.The hydrogen evolution reaction of ordinary photoelectric catalysis is mainly carried out in a photocatalytic manner under a small overpotential,and there is still a lack of systematic research on photo-assisted electrocatalytic HER.Therefore,it is of great research value to search for highly active HER catalysts assisted by light.Based on the above two problems,this thesis aims to construct three functional porous membrane materials,one is a Ru-supported mesoporous TiO₂ film on nickel foam,which can be used as photoassisted electrocatalytic hydrogen production.The other is NiFe-supported mesoporous TiO₂film on nickel foam which is used for electrocatalytic oxygen evolution.The third is a porous silica film which using waste glass as raw material prepared by one-step hydrothermal method for oil-water separation.The specific research contents are as follows:(1)Mesoporous TiO₂ composite membranes supported by ruthenium were prepared by a three-step process of self-assembly,impregnation and hydrogen reduction.Porous titanium dioxide film is evenly coated on the NF and the ruthenium is loaded in titanium dioxide pores by impregnation and reduction.The formation of Ru-TiO₂ structure can effectively improve the problem of inadequate absorption of visible light by TiO₂.The electrochemical performance of the electrocatalyst shows that the performance of HER is significantly improved under the light irradiation.With the assistance of light,the Ru-TiO₂@NF(6.1%At)electrocatalyst exhibits higher electrocatalytic hydrogen evolution activity.When the overpotential is 100m V,the current density under light is 12.4 m A cm^-2,and the current density under dark environment is 10.2 m A cm^-2.The performance is improved by about 21.5%.Our design can open up the new thought for developing electrocatalytic hydrogen production under the assistant of photo.(2)NiFe-TiO₂@NF composites with NiFe content of 5%,10%and 18%were prepared by evaporation-induced self-assembly and hydrothermal method.The matching interface structure can promote the charge transfer between met.al and support,thus improving the OER reaction performance of catalyst.The results of electrocatalytic performance test show that porous titanium dioxide catalyst carrier can effectively reduce the energy consumption of electrocatalytic reaction.When the current density is 10m A cm^-2,the overpotential is only 330m V,and the corresponding Tafel slope is 77 m V dec^-1.Moreover,the catalyst with 18%mass content NiFe-TiO₂@NF has a small electrochemical impedance and good catalytic stability.(3)Nanofiber meshes were synthesized on stainless steel mesh(SS)substrate using waste glass as raw material,and the effects of admixtures such as NaOH and NH₄F on the morphology of nanofibers were investigated.In addition,an attempt was made to remove the stainless steel mesh substrate and directly hydrothermally heat the glass powder to prepare an oil-water separation membrane.Then,the morphology of the obtained oil-water separation membrane was characterized by SEM,and its oil-water separation performance was tested.The test results show that the prepared nanofibers have excellent oil-water separation performance(oil-water removal efficiency>98%)in a wide pH range.