Preparation Of Ordered Mesoporous Metal Oxides Using Polystyrene-b-Polyvinylpyridine Block Copolymer As Templates

Mesoporous metal oxides are widely used in various fields such as catalysis and sensing because of their excellent properties.In particular,ordered mesoporous titanium oxide materials have attracted extensive attention due to their non-toxicity,low cost,high catalytic activity,etc.Therefore,how to prepare highly ordered mesoporous titania-based nanomaterials by a simple method is still a huge challenge.This thesis focuses on the preparation of ordered mesoporous titanium oxide nanomaterials and the study of photocatalytic properties.Firstly,the self-assembly of block copolymer polystyrene-b-polyvinylpyridine（PS-b-PVP）in solvent vapor annealing was studied,and the influence of various factors on its self-assembled structure was investigated.Secondly,the diblock copolymer polystyrene-b-poly（2-vinylpyridine）（PS-b-P2VP）was selected as the structure directing agent（SDA）to prepare a highly ordered two-dimensional hexagonal compound with photocatalytic properties.Mesoporous structure titanium dioxide-carbon nanomaterials.Finally,iron/platinum ions were introduced to prepare iron/platinum doped ordered mesoporous titania-carbon catalytic nanomaterials,which improved the photocatalytic degradation performance of visible light.The method is mild and controllable,opening up a new way for the design,preparation and doping of highly ordered mesoporous materials.（1）The block copolymer polystyrene-b-poly（4-vinylpyridine）（PS-b-P4VP）and3-npentadecylphenol（PDP）were used as a model system,and chloroform was used as a solvent.The strong hydrogen bond between the functional segment P4VP and the small molecule PDP can form a comb-like supramolecular assembly.In the process of saturated chloroform vapor annealing,a highly ordered columnar structure is prepared by controlling the annealing time.The effects of solvent evaporation rate,different composition of PS-b-P4VP and the type of vinyl pyridine on its morphology were investigated.The preparation of the ordered template provides a template for the preparation of the ordered mesoporous titanium oxide material.（2）The preparation of the ordered template provides a template for the preparation of the ordered mesoporous titanium oxide material.Selecting a carboxylate-containing titanium citrate（TIC）complex as a precursor,and a diblock copolymer polystyrene-b-poly（2-vinylpyridine）（PS-b-P2VP）as a structure directing agent（SDA）,pyridine（PY）and ethanol（ET）as solvents.The inorganic and organic components can be co-assembled by utilizing the carboxyl group in the TIC to form an intermolecular hydrogen bond with the pyridine group in the solvent pyridine and the P2VP block.A highly ordered two-dimensional hexagonal mesostructured titanium oxide-carbon nanomaterial was prepared by solvent eVaporation induced self-assembly（EISA）.When the PY:EH（volume ratio）=0.25:1,TIC:P2VP（molar ratio）=2.0:1,under 500℃calcination 8 h,in whose condition the order of the titanium oxide-carbon nanomaterials is most regular..It has photocatalytic activity under both ultraviolet and visible light conditions.Under UV irradiation,the degradation rate of methylene blue was nearly 100%in 90 min.Under visible light irradiation,the degradation was completed in 360 min,and the visible light catalysis was much higher than that of commercial catalyst P25.（3）On the basis of the second chapter.The Pt-doped and Fe-doped ordered mesoporous titania-carbon nanomaterials were prepared by adding the metal precursors H₂PtCl₆·6H₂O and FeCl₃·6H₂O to the system by using the pyridine group and some metal ions to form complexes.The results show that the doping greatly improves the visible light photocatalytic activity of ordered mesoporous titania-carbon materials while maintaining a highly ordered mesoporous structure.This good visible light catalytic performance can be attributed to the presence of metal doping,nitrogen doping,the presence of amorphous carbon,and synergistic effects in ordered mesoporous titania.