Method for preparing composite metal oxide with graded porous structure

Abstract

The invention provides a method for preparing a composite metal oxide with a graded porous structure. The method comprises the following steps of: pouring a bivalent metal salt and a trivalent metal salt into a container filled with a mixed solvent of ethylene glycol and water, placing the container into a closed container filled with thick aqueous ammonia after dissolution, and reacting the volatilized aqueous ammonia and the metal salts on the surface of the solution layer by layer at room temperature to generate hydrotalcite sol; and pouring out the transparent solution of the upper layer,transferring the rest sol into a crucible, insulating and ageing the sol for 12 hours at the temperature of between 80 and 180 DEG C, directly performing suction filtration on the aged sol under reduced pressure, drying the obtained filter cakes in an oven, finally putting the dried gel product into the crucible, roasting the gel product for 5 hours at the temperature of between 300 and 500 DEG C, and cooling the roasted product to room temperature to obtain the graded porous composite metal oxide. The hydrotalcite sol with three-dimensional spatial network structure is formed by adopting a gas-liquid interface reaction method, and the hydrotalcite sol is dried and roasted to prepare the composite metal oxide with the graded porous structure.

Description

technical field [0001] The invention relates to a method for preparing a composite metal oxide with a porous structure. Background technique [0002] Due to their unique pore structure and excellent specific surface properties, porous materials have broad application prospects in the fields of catalysis, adsorption and separation. Porous materials with a hierarchical structure of specific micropores, mesopores or macropores have attracted more and more researchers' attention due to the combination of the advantages of pores of various sizes. So far, graded porous materials such as TiO 2 , ZrO 2 , CeO 2 And composite metal oxides are usually synthesized by applying templates. Commonly used templates include polyethylene colloidal particles, block copolymers, and ionic surfactants. However, these templating agents usually lack inherent complexity and hierarchical structure, making it difficult to obtain multi-sized pore structures and morphologies, and require tedious and ...

AI Technical Summary

Problems solved by technology

The disadvantage of biological templates is that it is difficult to ensure that the delicate biological tissue structure is not destroyed during the reaction.