介孔材料（Mesoporous material）.doc

1、介孔材料（Mesoporous material）classificationAccording to the classification of chemical composition, mesoporous materials can generally be divided into two major categories: silicon and non silicon.1. silicon based mesoporous materials have narrow pore size distribution, regular pore structure and mature

2、 technology. Silicon materials are available for catalysis, separation and purification, drug encapsulation, slow release, gas sensing and other fields. Silicon based materials can be divided into two groups according to pure silicon and other elements. The classification can be carried out accordin

3、g to the kinds of doped elements and the number of different elements. Heteroatom doping can be regarded as heteroatom instead of silicon atoms, introducing different heteroatoms will bring many new properties to the material, such as stability, changes of hydrophilic hydrophobic properties and the

4、change of catalytic activity change and so on.2. non silicon mesoporous materials mainly include transition metal oxides, phosphates and sulfides. Because of their existence of variable valence states, it is possible to open new application fields for mesoporous materials and demonstrate the potenti

5、al applications of silicon-based mesoporous materials. For example: aluminum phosphate molecular sieve P materials have been replaced by Si after the formation of silicon aluminium phosphate (silicon-aluminophosphate, SAPOs), aluminum phosphate introduced two valent metal in the architecture (metal-

6、substituted AIPOs MAPOs) has been widely used in adsorption, catalyst, acid catalysis, oxidation catalysts (such as methanol Olefination of hydrocarbons oxidation) etc. Activated carbon with large surface area and high pore volume has become the main industrial adsorbent because of its high adsorpti

7、on capacity and the adsorption of different types of compounds from the gas and liquid. In addition, the charge storage capacity of the double layer capacitor material made of mesoporous carbon is higher than that of the metal oxide particle, and the capacitance is much higher than that of the comme

8、rcial metal oxide double layer capacitor. Titania based mesoporous materials have many advantages such as high photocatalytic activity and high catalytic capacity. Many studies have been done on their structure, properties and characterization.synthetic methodIn general, mesoporous molecular sieves

9、are inorganic materials that constitute the framework of the molecular sieve. In the solvent phase, a series of ordered porous materials are formed by supramolecular self-assembly under the action of surfactant templates. The most commonly used synthetic methods are hydrothermal synthesis, and other

10、s have been reported, such as room temperature synthesis, microwave synthesis, wet gum calcination, phase inversion, and synthesis in nonaqueous systems. The main theoretical basis for the selection of inorganic species is sol-gel chemistry, that is, the rate of hydrolysis and condensation of raw ma

11、terials is equal, and the degree of polycondensation is improved by hydrothermal process. According to the skeleton composition of the target mesoporous material, the inorganic species can be directly added inorganic salts, or organic metal oxides which can produce inorganic oligomers after hydrolys

12、is, such as Si (OEt) 4, Al (i-OPr) 3, etc.Used for surface active synthesis of mesoporous molecular sieve material agent has many kinds, but according to the different electrical properties of hydrophilic groups, can be broadly divided into the following four categories: anionic, polar gene negative

13、ly charged; the cationic, with positive polarity genes; the non ionic, polar groups not charged; the amphoteric, with two hydrophilic groups, a positive and a negative charge, such as three CAPB (ethylene methyl amine in vinegar end is four yuan, the positively charged amine and the other end is neg

14、atively charged carboxyl) etc. The interfacial force between the polar head of the surfactant and the inorganic species is one of the common points in the formation of mesoporous molecular sieves in different synthetic systems. Various synthetic routes can by changing the type of phase interface for

15、ces (such as electrostatic interaction, hydrogen bonding or coordination effect) or variable size (such as charge density modulation can adjust a two-phase micellar surface electrostatic attraction size; adjusting reaction temperature can be adjusted to achieve the size of the hydrogen bond force).

16、Different inorganic species and surfactants can form specific synthetic systems under different assembly conditions and assemble into mesoporous molecular sieves with different structures, morphologies and pore sizes.Several important research stagesThe synthesis of mesoporous materials began in 199

17、0, and Yanagisawa and other layered silicate materials Kanemite and long chain Wan Jisan amines (ATMA) were mixed under alkaline conditions,Three dimensional mesoporous silica materials with narrow pore size distribution were obtained by ion exchange. It was the earliest discovered mesoporous silica

18、 material, but it did not attract the attention of scientists at that time because of its unsatisfactory structure. Until 1992, Mobils Kresge and Beck reported the successful use of cationic surfactant, synthesis of the new M41S series of silicon oxide with adjustable pore size in the range of 1.5-l

19、0nm as template (aluminum) based ordered mesoporous materials, for the study of ordered mesoporous materials sounded the horn ring.Contains a series of cage mesoporous materials synthesized by Stucky in 1994, compared with the synthesis of M41S mesoporous materials, he is using the surface active ag

20、ent double chain structure under acidic conditions at room temperature or short time low temperature synthesis.In 1995, chemical modification of mesoporous materials occurred successively, Es1. The chemical modification of mesoporous materials includes the doping of the backbone and the modification

21、 and functionalization of the pore surface. The doping of the framework mainly refers to the introduction of Al3+, Ti4 +, B3 + and other atoms in the framework of pure silicon mesoporous materials to give them the acid, alkali center or catalytic activity point. Functionalization of mesoporous pore

22、surfaces is the most widespread and effective method for preparing mesoporous host guest composite materials. For example, for modification can improve the hydrothermal stability of the materials by using hydrophobic substances, improve the adsorption performance of gas; modified catalyst performanc

23、e developed for specific chemical reactions using with catalytic materials; mesoporous materials modified by thiol and thioether groups of Hg 2 + Pb 20 the adsorption of heavy metal ions such as sichuan.The successful synthesis of ordered mesoporous thin films was first reported by Brinker et al in

24、1997. The use of acid alcohol solution as reaction medium and evaporation induced self-assembly (EISA) synthesis of high quality silicon oxide mesoporous films can process, which opened up broad prospects for the application of mesoporous materials in the field of membrane separation and catalysis,

25、microelectronics, sensors and photoelectric devices etc.It was first reported in 1998 by Zhao non-ionic SBA-15 mesoporous materials with large aperture synthesis of three block copolymers, due to its large pore wall thickness (5-30nm) and (3.1-6.4nm) the thermal and hydrothermal stability has been s

26、ignificantly improved, so as to broaden the scope of application of mesoporous materials. At present, the research reports based on SBA-15 mesoporous materials are the most widely used in the field of mesoporous materials.In 1999, Ryoo successfully replicated other mesoporous materials with mesoporo

27、us materials as hard templates. He has to MCM-48, SBA-1, SBA-15 as template to replicate the CMK-1, CMK-2, CMK-3 mesoporous carbon molecular sieve materials, and provides a feasible route and then the successful synthesis of precious metals, metal oxides, sulfides and other non silica based mesoporo

28、us materials.In 2003, Zhao et al proposed a acid base concept, using a pair of inorganic precursors of acid-base pairing to synthesize a series of non porous mesoporous materials in non-aqueous systems by self regulating acidity. This method has solved the problem of finding the precursor of metal s

29、ol to a certain extent and is a general method for synthesizing porous materials with multiple oxides.In 2004, Che reported the use of anionic chiral surfactants as templates to synthesize chiral mesoporous materials with helical channels. This mesoporous material with unique pore structure is expec

30、ted to play a role in chiral molecular recognition, separation and catalysis.applicationChemical and chemical fieldsOrdered mesoporous materials have large specific surface area, relatively large pore size and regular pore structure, and can handle larger molecules or groups. They are very good shap

31、e selective catalysts. The ordered mesoporous materials show better catalytic activity than zeolite molecular sieves, especially in the reactions catalyzed by bulky molecules. Therefore, the use of ordered mesoporous materials opens up a new world for catalytic cracking of heavy oil and residuum. Wh

32、en ordered mesoporous materials are directly used as acid-base catalysts, the carbon content of the solid acid catalyst can be improved, and the diffusion rate of the product can be improved. The conversion rate can reach 90%, and the selectivity of the product is up to 100%. In addition to direct a

33、cid catalysis,Graft materials can also be prepared by mixing transition elements in the framework of ordered mesoporous materials with redox power, rare earth elements, or supported redox catalysts. The graft material has higher catalytic activity and shape selectivity, which is the most active fiel

34、d for the development of mesoporous molecular sieve catalysts at present.Ordered mesoporous materials can also be used in the field of polymer synthesis, especially polymerization reactors, because of their large pore size. Because the hole reduces the chance of polymerization termination to a certa

35、in extent, prolong the life of free radicals, and molecular ordered mesoporous materials synthesized by weight distribution of the polymer was better than the corresponding condition of the free radical polymerization of narrow, by changing the molecular monomer and initiator amount can control the

36、quantity of polymer. In addition, the active center can be typed or introduced into the framework of the polymerization reactor to accelerate the reaction process and increase the yield.In the environmental control and protection, it is used to degrade organic waste, and is used for water purificati

37、on and the conversion treatment of automobile exhaust. In the field of high technology and advanced materials for energy storage materials for the assembly of functional nano object in mesoporous materials, such as assembly of guest molecules, luminescence properties for the light emitting assembly,

38、 photochemical active substances, allowed to use the advantages of mesoporous materials with large surface area of the prepared mesoporous structure of optical materials than conventional optical more excellent materials, such as the Chinese Academy of Sciences Shanghai Institute of ceramics Shi pan

39、 Jianlin with mesoporous composite film ultrafast nonlinear optics corresponding group preparation. The optical applications of mesoporous materials, Stucky, G, D and so on, have been discussed in 2000. In the uniform pore through the polymer mediated polymerization, then chemically removed pore, ca

40、n form conductive polymer materials with regular mesoporous structure, the use of structured mesoporous materials as pore micro reactor and its carrier function to synthesize heterogeneous nanoparticles or quantum wire composite assembly system has a special advantage. The small size effect and quan

41、tum effect due to limited pore size and regular action, has observed this kind of composites can exhibit optical properties and electric and magnetic special, such as modified mesoporous zirconia materials after the show special room temperature photoluminescence. These can be used for the research

42、and development of mesoporous and composite materials in optical devices, micro sensors and other fields.Ordered mesoporous materials are the branches of porous materials, and their rapid development also comes from the practical application of industrial (such as petroleum, chemical, fine chemical)

43、. At the same time, we should also see that the ordered mesoporous materials, the pore size in the range of 250nm, which provides a reaction vessel for the preparation of new nano materials and nano composite materials, or tools. In 1992 M41S, the rapid development of nano science and technology coi

44、ncided with the period during which they prepared many new materials nanometer size, nano structure, such as the typical study of carbon nanotubes. I think, on the other hand, in the late twentieth Century, the development of nanotechnology led to the development of ordered mesoporous materials.Biom

45、edical fieldIn general, biological macromolecules such as proteins, enzymes, nucleic acids and so on, when their molecular mass of about 1100, between the size of less than 10nm, the relative molecular mass of about 10 million of the virus, its size is about 30nm. The pore size of ordered mesoporous

46、 materials can be adjusted continuously in the range of 2 - 50nm and has no physiological toxicity, which makes it suitable for the immobilization and separation of enzymes and proteins. It is found that ordered mesoporous materials such as glucose and maltose can successfully solidify the enzyme an

47、d inhibit the leakage of enzymes, and the enzyme immobilization method can keep the enzyme activity very well.The appearance of biochip is a very important progress in the field of high and new technology in recent years. It is a new technology that combines physics, microelectronics and molecular b

48、iology. The advent of ordered mesoporous materials has led to a breakthrough in this technique, and the formation of successive, firmly bound membrane materials on different ordered mesoporous material substrates,These membranes can be directly separated from cell /DNA for use in building microchip

49、labs.Direct encapsulation and controlled release of drugs are also good applications of ordered mesoporous materials. With ordered mesoporous materials, large specific surface area and pore volume, pore in the material can be set on porphyrin, pyridine, or immobilized protein and other biological dr

50、ugs, through the modification of controlled-release drugs, improve the efficacy of persistence. Biological targeting can effectively and accurately hit targets, such as cancer cells and lesions, and give full play to the efficacy of drugs.Environment and energyThe application of ordered mesoporous m

51、aterials as photocatalyst for the treatment of environmental pollutants is one of the focuses in recent years. For example, the mesoporous TiO2 ratio of nano TiO2 (P25) has a higher photocatalytic activity, because mesoporous structure with high surface area in contact with organic molecules increas

52、ed, increasing the surface adsorbed water and hydroxyl reaction, hole water and hydroxyl with the catalyst surface excitation produces hydroxyl radical, and hydroxyl radical is the strong oxidant degradation of organic matter, can put a lot of refractory organic matter oxidation to CO2 and inorganic

53、 water etc. In addition, selective doping in ordered mesoporous materials can improve the photocatalytic activity and increase the efficiency of photocatalytic degradation of organic wastes.Chlorine disinfection process is currently widely used in domestic water while killing all bacteria, but also

54、produce chloroform and carbon tetrachloride and chloroacetic acid and a series of toxic organic compounds, the serious three letter effect (carcinogenic, teratogenic, mutagenic) has caused widespread concern in the international science and medicine. The school received gamma 3-chloropropyltriethoxysilane in the inner wall of mesoporous materials, obtained mesoporous molecular s