Preparation And Application Of Mesoporous Composite Metal Oxides Based On Soft Template Method

Mesoporous composite metal oxides（MMOs）have received extensive attention in the catalytic field due to their advantages of both mesoporous materials and the synergism between different metal ions.The construction of high active sites is the key to the design of these catalysts.In this thesis,mesoporous WO₃@TiO₂and mesoporous MoO₃@ZrO₂composite materials with high exposure to the edge of the lattice layer and good channel structure were prepared by soft template,hydrothermal induced solvent-limited assembly and solvent-assisted calcination,and were applied to photocatalytic degradation of methyl orange（MO）and the acetylation reaction of alcohol（phenol）respectively.The main research contents are as follows:1.Using the principle of solution concentration driving surfactant aggregation and separation,in the process of solvent volatilization,the surfactant and organic precursor molecules self-assemble through non-covalent bonds,the organic precursor molecules are cross-linked by reaction,and finally the surfactant is directly removed by thermal decomposition-calcination to prepare mesoporous titanium dioxide and mesoporous zirconia nanomaterials.Due to the amphiphilic nature of block copolymer F127,functional precursor molecules can be introduced through hydrothermal induced solvent limited assembly method to form mesoporous nanomaterials with adjustable channel structure.Using the solvent assisted calcination technology,the precursor gel of titanium obtained by the hydrothermal induced solvent limited assembly method with soft template was combined with molybdenum oxide through van der Waals force to obtain a series of mesoporous WO₃@TiO₂heterojunction with different mole ratios of Ti and W.Mesoporous MoO₃@ZrO₂compound material is obtained by the same method and principle.The composition and morphology of the material were characterized by TEM,SEM,XRD,EDS,XPS,SAED,HRTEM and BET.2.The mesoporous WO₃@TiO₂heterojunction composite material was used for photocatalytic degradation of MO.A series of mesoporous WO₃@TiO₂heterojunction with different mole ratios of Ti and W were studied through photocatalytic degradation of MO,fitting reaction kinetic equation and UV-visible diffuse reflectance test.The catalytic performance of heterojunction composite catalyst is explored through the capture experiment of active substances and electron paramagnetic resonance.On the basis of mastering the relationship between the structure and performance of composite materials,the WO₃@TiO₂heterojunction composite catalyst with 3:1 mole ratios of Ti and W（TW-31）is the best catalyst and exhibits excellent catalytic activity and good prospects for photocatalytic applications.3.The mesoporous 15 wt%MoO₃@ZrO₂composite materialis was used as a solid acid catalyst in the acetylation of alcohol（phenol）.The mesoporous catalyst has high exposure and excellent catalytic performance.The yield of acetylation is above90%;the experimental conditions are mild,green and easy to operate;the catalyst has stable chemical properties,still has high catalytic activity and structural integrity after five catalytic cycles.The development of this kind of composite metal oxide solid acid catalyst provides a new way for the protection of alcohol（phenol）hydroxyl.