Preparation,Characterization And Catalytic Performance Of Hierarchical Composite Functional Materials

Since the beginning of new century,material revolution has been flourishing.Design,preparation and application of new materials has become a cornerstone of the upgrading and development of the industry.Grasping the new material technology is the initiative to grasp the future development.As an important green energy source,light energy has been an important part of China's energy strategy.Traditional photocatalysts are mainly semiconductor materials with ultraviolet response,which have the disadvantages of poor adsorption capacity and small specific surface area,which' make their application suffer from many defects.Hierarchical composite materials have received more and more attention due to their hierarchical structure and functional composite advantages.Molecular sieves are widely used in the field of industrial catalysis because of their pore structure and skeleton characteristics.In addition to excellent shape selectivity,the micropores of the molecular sieve also greatly retard the material transport during the reaction.Shortening the diffusion path and designing and preparing molecular sieves with hierarchical pore systems have become hot topics in molecular sieve research in recent years.Transition metal modification is an important method of molecular sieve modification.Combining the advantages of both,it is of great practical significance to study transition metal-modified molecular sieve materials with hierarchical pore structure.In this paper,a series of hierarchical MnAPSO-34 molecular sieves were controllably prepared by the seed-assisted method,and a novel waxberry-shaped TiO2/SiO2 hierarchical composite nanosphere was controllably prepared by the microemulsion soft-template method.The optimum process conditions and methods for the two hierarchical composite materials were explored in detail,and their photocatalytic degradation performance was evaluated.The main work of this paper and the results achieved:1.Using diethylamine as a structure-directing agent,a hierarchical SAPO-34 molecular sieve with a micropore-macroporous composite structure was controllably prepared by seed-assisted method,and the particle size was about 3.64?m.The formation process of hierarchical structure was studied in detail.The effects of structure-directing agents,silicon content and amount of seeds on the pore structure and surface properties of the material were investigated,and a series of regular results were obtained.2.A series of hierarchical MnAPSO-34 molecular sieves were controllably prepared on the basis of seed-assisted combination of transition metal modification process.The influence of the structure-directing agent type,manganese content and other factors on the structure and properties of the material was investigated in detail.With methylene blue as a probe,its visible light degradation behavior of organic pollutants was investigated.The photocatalytic activity of Mn/Al2O3=0.15 was the best.After 300 min of visible light irradiation,the degradation rate of 0.05 g catalyst to 50 mL of 0.01 g�L-1 methylene blue solution was 80.04%,which shows good cyclic degradation activity and stability.3.A novel waxberry-shaped SiO2 hierarchical nanospheres was prepared using a microemulsion formed from ethyl acetate and cetyltrimethylammonium bromide as soft templates.In the mixed precursor solution with different titanium-silicon ratio,the waxberry-shaped TiO2/SiO2 hierarchical composite nanospheres were prepared by soft-template method.The effects of the amount of n-octane,the concentration of ammonia,and the ratio of titanium to silicon on the morphology and structure of the material were investigated.And using Rhodamine B as a probe,its UV degradation behavior of organic pollutants was investigated in detail.The photocatalytic activity of Si/Ti=3 sample was the best.After 120 min UV irradiation,the degradation rate of 0.05 g catalyst to 50 mL 20 mg L-1 Rhodamine B solution was 96.73%.