The Synthesis And Preliminary Study On Mechanism Of Lamellar Mesoporous ZrO₂

Mesoporous size,regular pore structure and good surface cohesion characteristics of mesoporous ZrO₂ are more effective for various types of catalytic reaction(such as the oxidation and acid catalyst) and adsorption.And mesoporous ZrO₂ also shows excellent catalytic properties in dehydration,hydrogenation and hydrogen exchange reaction.The synthetic process of mesoporous ZrO₂ is affected by a wide range of impact and its synthetic mechanism is complicated.Therefore,exploring the synthetic methods and optimizing the synthetic conditions of mesoporous ZrO₂ still have practical significance.In this article, lamellar mesoporous ZrO₂ was synthesized with inexpensive industrial ZrOCL₂·8H₂O, analysis level NH₄HCO₃ and domestic surfactant——SBS.This work discussed the influence of the reaction conditions for the pore structure and morphology of the product.Furthermore, preliminary study on synthetic mechanism of mesoporous ZrO₂ was investigated.The main contents are shown as follows:First,the article reviewed the mechanism research of mesoporous materials,and emphasised on research progress of mesoporous ZrO₂ and the main problems of current preparation of mesoporous ZrO₂.Second,critical micelle concentration of SBS was tested by conductivity method in different conditions.The result is as below:1) Critical micelle concentration of SBS was gradually increscent with the increasing temperature,and they even showed linear relationship.We could surmise critical micelle concentration of SBS in the experiment from the specification curve.2) Electrical conductivity and concentration of SBS showed linear relationship in large concentration range above critical micelle concentration of SBS.This showed that the change of micelle form with concentration of SBS can not be measured by conductivity method.3) Critical micelle concentration of SBS was reduced by the addition of Zr⁴⁺.Third,orderly lamellar mesoporous ZrO₂ was synthesized by hydrolysis-deposition method and hydrolysis-hydrothennal method.The influence of the different synthetic conditions on the pore structure and morphology of product were surveied.The optimum reaction conditions were determined and long-distance orderly lamellar mesoporous ZrO₂ was prepared.We found that the products prepared with the two methods are long-distance orderly lamellar mesoporous structure.And the difference in the products was that the product prepared with hydrolyzing-deposition method was amorphous powder and the one prepared with hydrolysis-hydrothermal method was tetragonal phase and hemihedral crystal structure. We preliminarily infered that mechanism of mesoporous ZrO₂ prepared with the two methods were coordination mechanism.Forth,in order to explore soft and effective way for removing template in the preparation of mesoporous ZrO₂,we compared the common methods——calcination method with extraction method in the effect of removing template.The conclusion is as below:calcination method could effectively remove the template,but it made pore structure of mesoporous ZrO₂ collapsed;extraction was soft and the templates.could be recoved and reused,and it could remove part of template but it needed a long time;the efficiency of oxidation-extraction was better than general extraction,but it also needed to be improved.