| Mesoporous materials refer to the material with the pore size in the range of 2 to 50 nm. Mesoporouse materials can be divided into “silicon-based” and “non silicon-based” material according to the chemical composition. However, the mesoporous materials are also classfied as amorphous and ordered materials according to their channal order properties. Mesoporous materials possess attractive properties, such as high surface areas, tunable pore sizes and shapes, good mechanical stability, electrical conductivity and the surface can be modified, which endow them with potential applications in drug targeting transport, industrial catalysis, environmental protection, adsorption seperation, chemical sensors and so on.Templating methods can be divided broadly into two classes according to the properties of templates used in synthesis, which can be called templating methods and template-free(also called self- templating) methods, respectively. In templating methods, there are two main templates, one is hard templates, such as polymer latex particles, metal particles and carbon materials, the other is soft templates, suc as macromolecule, surfactant micelle, micro- emulsion and bubble. The template-free methods mainly include Ostwald ripening, K irkendall effect, galvanic replacement and chemical etching. These two synthelic methods have their advantage and disadvantage. We can synthesise simple with virous shapes and structures using templating methods because of a wide range of templates. However, we need to remove the templates by calcination or extraction and this process may cause the structure collapse as well as increses the cost. The synthesis using template- free mrthods depend on nanoparticles diffusion and self- assembly to be hollow materials, and this process don’t need the addition of other template and are more green and environmental friendly without template remove.People have made great progress in mesoporouse silica and titanium oxide materials at present. As the mesoporouse Si O2 and Ti O2 existing can not meet the most industrial applications fully, so it is necessary to develop new synthesis route to regulate the micro and macro structure of this two materials more convenient and to look for low cost, low toxicity and recyclable templates.In this article we synthesised the mesoporous Si O2 by templateing method and the mesoporouse hollow Ti O2 by template-free method, that is Ostwald ripening. We got a series of mesoporous materials wirh various morphologies by regulating and controlling the experimental conditions. The characterization of the samples were carried out by SEM、TEM、XRD、TG、N2-adsorption/desorption measurement. The detail informatiion as following:With cetyl trimethyl ammonium bromide(CTAB) and Sodium dodecylbenzene sulfonate(SDBS) as dual templates, TEOS as the silica source, ammonia water as the catalysis, alcohol and diethyl ether as cosolvent, using a facile sol- gol method synthesised the mesoporous silica microspheres. We investigated the ratio of two surfactants, and found that when CTAB/SBDS was 4, the sample with uniform size and best dispersibility was prepared. When change the concentration of suefacta nts, the sample prepared at 0.028mol/L was the best. If we change the volume ratio of ethanol to diethyl ether, the microsphere size was gradually increasing with the ethanol increasing and the volume ratio less than 1.25, then the microsphere size was decreasing and bicame nonuniform as more ethanol was added, a nd the possible mechanism was investigated for using two cosolvent to synthesise mesoporous silica microsphere. In constrast with the conventional vesica template, this synthesis route was more easily to control the Si O2 microsphere size and the other parameters in the process. Then this route maybe more suited for industrialization control and mass production.The fouth part of this study, with TBOT and TTIP acted as the titanium source, and gradually droped into the ethanol solution with trace KCl to form the amorphous Ti O2 nanoparticles(in this process, trace ammonia water need to add when TTIP acted as titanium source and needn’t to add when TBOT). Then the synthesised amorphous Ti O2 nanoparticles was hydrothermal treated in a NH4 F solution and finally got a anatase hollow Ti O2 micreosphere under the F- induction. When the TBO T acted as titanium source, wo studied the aging temperature’s effect and found that the sample prepares at room temperatur e have a uniform size and this sample still was solid microsphere as other sample were hollow microsphere or massive substance with macroporous on it after hydrothermal treatement. With the increasing of KCl concentration, the diameter of particles was dec reasing and when KCl more than 0.8ml, there is no product synthesised. When the TTIP acted as the titanium source, we explored the influence of the amount of ammina water on product, and the result show that when the best volume of ammina water was 5μl. At last, we studied the effect of NH4 F concentration on product, and found that with the increasing of NH4 F concentration, the morphology of Ti O2 was destroyed and Ti O2 crystallization property enhanced. This work have done a more deep research about the inf luence factors in the Ostwald riping process to synthesis Ti O2 and reported the influence of aging temperature to the morphology and structure of the product at pretreatment process. |
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