CN1623888A - Process for synthesizing nano metal mesonic porous compound - Google Patents

Abstract

The invention discloses a method for synthesizing a nanometer metal mesoporous complex. In this method, a metal salt containing one of Au, Pt, Pd, Ag, Ru, and Cu is dissolved in a system of aromatic heterocyclic compounds and water to prepare a solution; Stir and react for 0.3-1.5 hours, then add tetraethyl orthosilicate to obtain a gel of nano-metal mesoporous complexes, and finally statically crystallize at 80-200°C for 24-72 hours, filter, wash, and dry to obtain nano-metal mesoporous composites. The dry cake of metal mesoporous complex is calcined at 450-600°C to obtain the nano metal mesoporous complex. The prepared nanometer metal particle has a small particle size between 2.5-50nm and good dispersion.

Description

Synthesis method of nano-metal mesoporous composite

technical field

The invention discloses a method for synthesizing a nanometer metal mesoporous complex.

Background technique

Mesoporous solids and mesoporous complexes have been attractive research objects in the field of nanomaterials science in recent years. Due to the high porosity (pore size of 2-50nm) and high specific surface of this material, it can be used in adsorption, It has important application prospects in filtration and catalysis. On the other hand, if different kinds of nanoparticles are assembled into the cavities of mesoporous solids, exotic optical, magnetic, and electrical properties can emerge. This characteristic is not only different from the matrix material of mesoporous solids, but also different from the assembled nanoparticles, and new physical properties may appear. In this sense, mesoporous composites provide a new way for the synthesis of new materials. way. At present, the most commonly used method for preparing nanoparticles in the world is to reduce metal ions by chemical or electrochemical methods. In order to prevent the agglomeration of the generated nanoparticles, a certain amount of protective agent is generally added during the reduction process to stabilize the generated particles. Materials commonly used as protective agents include linear polymers, organic ligands, surfactants, tetrahydrocarbyl ammonium salts, and certain heterogeneous carriers. Mesoporous molecular sieves have the periodicity of channel space or nanocages and the perfection of topology. Chemical modification methods are used to introduce inorganic semiconductors, organic compounds, metal carbonyl compounds and other substances into their cages or channels, greatly improving the performance of mesoporous molecular sieves. , forming an excellent functionalized mesoporous molecular sieve material. The in-pore modification of mesoporous molecular sieves is to introduce nanoscale metal or non-metal ultrafine particles into the pores (or cages) of mesoporous molecular sieves by physical or chemical methods to form mesoporous complexes. It has some unique properties of nanoparticles and mesoporous solids, but it is by no means a simple addition of the two, but has some special properties through interface coupling and changes in the microenvironment in the pores, which can be used for heterogeneous selective catalysis, Specific selective separation, electronics, optical and magnetic storage and many other fields have produced various new functional materials.

Contents of the invention

The purpose of the present invention is to obtain a method for preparing nano-metal mesoporous composites which is simple, fast and generally applicable.

The purpose of the present invention is to realize through the following technical solutions:

The modification in the mesopore mainly has the following two methods: I. Grafting on the inner wall of the mesopore; II. Mosaic in the mesopore. Using aromatic heterocyclic compounds and their derivatives as stabilizers and templates, we synthesized nano-metal mesoporous composites with nano-metal inclusions in the pores of MCM-41 through the "S ⁺ X ^- I ⁺ " route.

A kind of synthesis method of nanometer metal mesoporous composite body, it is characterized in that the metal salt containing one of Au, Pt, Pd, Ag, Ru, Cu is dissolved in the system of aromatic heterocyclic compound and water and makes solution, wherein The mass ratio of aromatic heterocyclic compound, metal salt, and water is 1:0.01-0.05:1-6, and the aromatic heterocyclic compound is selected from pyridine, cetylpyridine bromide, tetradecylpyridine bromide or brominated Dodecylpyridine; add one of KBH ₄ , NaBH ₄ , and hydrazine hydrate as a reducing agent to the above solution, stir and react at 0-60°C for 0.3-1.5 hours, and then add tetraethyl orthosilicate (TEOS) , the gel of the nano-metal mesoporous complex is obtained, and finally statically crystallized at 80-200°C for 24-72 hours, filtered, washed and dried to obtain a dry cake of the nano-metal mesoporous complex, which is baked at 450-600°C Nano-metal mesoporous composites were obtained.

The metal salt of the present invention is selected from one of HAuCl ₄ , H ₂ PtCl ₆ , Pd(NO ₃ ) ₂ , PdCl ₂ , RuCl ₃ , Ag(NO ₃ ) ₃ , AgC ₂ H ₃ O ₂ , and CuSO ₄ .

The outstanding features of the invention are: (1) the prepared nano-metal particles have a small particle size of 2.5-50nm and good dispersibility; (2) the reaction temperature is low and the temperature application range is wide. (3) The reaction process is simple to operate.

Detailed ways

The following examples are provided to further illustrate the present invention. Obviously the embodiment of the present invention is not limited to subordinate

Example 1-4

Add 0.02g H ₂ PtCl ₆ and other metal solutions to a solution of 5 grams of aromatic heterocyclic compounds and 40 ml of distilled water to form a transparent liquid, and add KBH ₄ under vigorous stirring. Continue to stir for 1-1.5h at 25°C to obtain a colloidal solution of metal nanoparticles, add tetraethyl orthosilicate (TEOS) dropwise to the sol to obtain a gel of nano-metal mesoporous composites, and mix the gel solution Transfer to an autoclave for static crystallization at 80-200°C for 24-72h, filter, wash, and dry to obtain a dry cake of nano-metal mesoporous composites, and roast in an air atmosphere at 450-600°C to remove aromatic heterocyclic compounds to obtain nano-metal mesoporous composites body. Aromatic heterocyclic compounds: (1) cetylpyridine bromide, (2) tetradecylpyridine bromide, (3) dodecylpyridine bromide;

Example 4-7

According to the method and step of example 1, but change the metal component to be:

(4) PdNO ₃ ;

(5) _CuSO4 ;

(6) RuCl ₃ ;

(8) _PdCl2 ;

Examples 8-11

According to the method and steps of Example 1, the system reaction temperatures of Examples 8-11 were respectively set to 0°C (8), 20°C (9), 40°C (10), and 60°C (11).

Examples 11-14

The method and steps of Example 1 were followed, but the high temperature crystallization temperatures were 80°C (11), 100°C (12), 150°C (13), and 200°C (14).

Claims (2)

1, a kind of synthetic method of nanometer metal mesoporous composite body, it is characterized in that the metal salt containing one of Au, Pt, Pd, Ag, Ru, Cu is dissolved in the system of aromatic heterocyclic compound and water and makes solution , wherein the mass ratio of aromatic heterocyclic compound, metal salt, and water is 1:0.01-0.05:1-6, and the aromatic heterocyclic compound is selected from pyridine, cetyl bromide, tetradecyl pyridine bromide or Dodecylpyridine bromide; Add one of KBH ₄ , NaBH ₄ , and hydrazine hydrate as a reducing agent to the above solution, stir and react at 0-60°C for 0.3-1.5 hours, then add ethyl orthosilicate, The gel of the nano-metal mesoporous complex is prepared, and finally statically crystallized at 80-200°C for 24-72 hours, filtered, washed, and dried to obtain a dry cake of the nano-metal mesoporous complex, which is roasted at 450-600°C. Nanometal-mesoporous composites. 2. The method according to claim 1, characterized in that the metal salt is selected from HAuCl ₄ , H ₂ PtCl ₆ , Pd(NO ₃ ) ₂ , PdCl ₂ , RuCl ₃ , Ag(NO ₃ ) ₃ , AgC ₂ H ₃ One of O ₂ and CuSO ₄ .