CN1911786A - Preparation method of mesopore metal oxide - Google Patents

Abstract

The preparation method of mesoporous metal oxide: dissolve the metal salt in acrylic acid, the molar ratio of metal salt and acrylic acid is 1:0.1~10, stir for 0.2-2h, filter with suction respectively, and wash with distilled water and alcohol for 1-3 times respectively. Drying: spread the dry powder in a crucible, and bake in a muffle furnace at a temperature of 200-350°C for 3-8 hours, and the heating rate is 2-8°C/min. The invention has short reaction time and short preparation period.

Description

Preparation method of mesoporous metal oxide

1. Technical field

The present invention relates to a mesoporous metal oxide (including CeO2, Nb ₂ O ₅ , Ta ₂ O ₅ , CuO, V ₂ O ₅ , NiO, ZnO, Fe ₂ O ₃ , Al ₂ O ₃ , TiO ₂ , ZrO ₂ , a new preparation method of SnO ₂ and SiO ₂ ) powder materials.

2. Background technology

Nanoscale materials have been the subject of numerous scientific and technological studies in recent years due to the potential applications of these materials in different fields, in which the potential applications of metal oxides have been more influenced by their electrical and magnetic properties. Much attention.

For example, Co ₃ O ₄ ultrafine powder is also widely used in pigments, colored glass, magnetic materials, ceramics, etc. In the electronics industry, it is required to have high purity, fine particle size, narrow particle size distribution range, and good sintering activity; in environmental protection chemistry In engineering, it is the most effective catalyst for CO reduction of SO ₂ , ammonia oxidation, and methane reduction of NO; in ceramic functional materials, it is widely used in the manufacture of thermal and pressure sensitive electrodes, gas sensors, magnetic materials and lithium ion cathode materials. In all these applications, the microstructure of Co ₃ O ₄ , such as grain size, distribution range, and crystal morphology are key parameters that affect and determine its performance. Nano Co ₃ O ₄ is a reddish-brown powder, insoluble in water, and magnetic .

Fe ₂ O ₃ is one of the main raw materials for making soft ferrite. It is widely used in electronic products such as color TVs, video cameras, computers, and communication equipment; α-Fe ₃ O ₄ can also be used in the coating industry, the market In great demand. It can be used as a catalyst to produce clean transportation fuel, and can also be used to make rechargeable lithium batteries. It also has important applications in the field of magnetic detection.

ZnO is a wide-bandgap semiconductor material with a hexagonal structure. The band gap at room temperature is 3.34eV, and the exciton binding energy is as high as 60meV. It is an excellent material for the preparation of ultraviolet optoelectronic devices and is an important semiconductor material. One of the oxide semiconductors that realize the quantum size effect, it has been widely used as photovoltaic cells, ceramics, pressure sensitive, sensors, catalysts, light-emitting materials, etc. At present, with the development of ZnO nano-preparation technology and the discovery of low-voltage high-efficiency fluorescent properties, the application of materials has further expanded to filter, makeup, flat panel display and other fields. These applications are closely related to particle size and its properties.

Materials such as Al ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ and SiO ₂ are widely used in catalysis and sensor manufacturing, and mesoporous materials with large specific surface and uniform pore size distribution are widely used.

The mesoporous structure (20-150 Å) of the metal oxides is produced to give these oxide materials special properties. This porous structure greatly increases the surface area of the metal oxide. The surface of these metal oxides is often the site of catalytic reactions, which significantly change the electrical, magnetic and optical properties of the material from pore to pore. Mesoporous silicon, aluminosilicates, aluminophosphates and related materials have been well prepared. However, synthesizing mesoporous structures of metal oxides is much more difficult. Because for oxide materials, due to the complex hydrolysis chemistry of metal ions and the numerous phases of corresponding oxides, the progress is relatively slow. Some initial work has achieved some success, like Nb ₂ O ₅ , TiO ₂ , ZrO ₂ , WO ₃ , and MnOx, using surfactants, including coordination-assisted surfactants. In 1992, the research work on synthesizing M41S series of ordered mesoporous SiO ₂ materials by the template method was reported. Since then, various materials (TiO ₂ , Nb ₂ O ₅ , Tb ₂ O ₅ , ZrO ₂ , V ₂ O ₅ , etc.) Mesoporous structures have been synthesized successively. Mesoporous materials have large specific surface area, uniform pore size and regular pore distribution, so that they have incomparable advantages in catalytic applications. It makes the application of catalytic materials more realistic. However, the traditional mesoporous synthesis method is more cumbersome, the synthesis cycle is longer, and the traditional use of surfactants is also more expensive.

Yang Ru; Liu Jianhong; Li Min applied for the Chinese patent "Preparation Method of Mesoporous Rare Earth Oxide" (Patent No. 02158777.9), which involves a preparation method of mesoporous rare earth oxide, including gel preparation, solvent replacement and roasting process. Dissolve rare earth strong salts with crystal water in deionized water to form a solution, then add water-soluble polymers or water-soluble organic alcohols and organic amines as mixed templates, and dissolve them with rare earth strong salts under high-speed stirring Form a chelate body, use ammonia water, urea and urea derivatives as precipitants, uniformly precipitate and react to form a rare earth element hydroxide mesoporous mesophase, after the reaction is complete, the product is aged, washed with deionized water, replaced with anhydrous ethanol, and dried and roasting to obtain mesoporous rare earth oxide powder. Acrylic acid is not used in its process, and the present invention is not inconsistent with it.

Zhang Jinlong; Yuan Shuai; Sheng Qiaorong; Chen Feng; Tian Baozhu; Sun Jian's Chinese patent application "a method for preparing titanium dioxide mesoporous materials" (patent number 200410025753.4) uses block copolymers as templates and prepares titanium dioxide mesoporous materials by sol-gel method material, whose invention must use block copolymers, the present invention does not conflict with it.

Sun Yinyong; Yuan Lina; Xiao Fengshou's Chinese patent "Mesoporous superacid material with high specific surface area and preparation method" (Patent No. 02132454.9) Mesoporous superacid material with high specific surface area and preparation method belong to the field of inorganic chemistry and physical chemistry. These superacid materials are composed of sulfurized metal oxides MXOY/SO42-, M=Zr4+, Fe3+, Ti4+, Sn4+, etc. Their specific surface area is 150-200m2/g, and the range of mesopores is 20nm-200nm. Its preparation method is to add water and stir the soluble salt of metal oxide in the presence of surfactant, and place it at 30-80°C for 0.5-500 hours, then add ammonia water to hydrolyze the solution to make the pH value of the solution 7-10, and obtain the precursor body, and then aged, vulcanized, and calcined to obtain a superacid material. The present invention does not need the sol-gel process, but the precipitate formed instantly after adding acrylic acid is calcined, and there is no conflict with it.

3. Contents of the invention

The object of the present invention is to develop a series of methods for preparing mesoporous metal oxide powder materials, which are convenient, fast, low in cost and strong in versatility. The obtained mesoporous material has a pore size of 3 nm to 10 nm, a narrow pore size distribution, and a worm-like disordered pore structure.

The object of the present invention is also to: aim at the shortcoming of traditional synthetic method, improve and explore on synthetic work, propose a kind of simple, efficient, fast, cheap synthetic method.

The technical solution of the present invention is: the preparation method of mesoporous metal oxide: the specific experimental steps promptly include specific process as:

1 Dissolve metal salts (including metal salts such as nitrates, chlorides, and sulfates) in aqueous solutions of acrylic acid, crotonic acid, and other enoic acids. The molar ratio of metal salts to acrylic acid or other enoic acids (stoichiometric ratio ) is 1:0.1～10 and stir evenly in a beaker.

2 Stir the beakers separately for 0.2-2h.

3 Suction filtration respectively, wash with distilled water and alcohol 1-3 times respectively, and dry.

4 Spread the dried powder in a crucible, and bake in a muffle furnace at a temperature of 200-350°C for 3-8 hours, and the heating rate is 2-8°C/min.

5. When the present invention is dried, it is placed in an oven at 50-80° C. for 2-5 hours and then baked in a muffle furnace.

6. During the preparation process of the present invention, heating or adjusting the pH value of the solution can be carried out.

The present invention also includes putting the beaker into an ultrasonic cleaner for ultrasonic treatment for 3-15 minutes, and then performing water washing and suction filtration.

The metal salts include sulfates or nitrates of titanium tetrachloride, cobalt nitrate, zinc sulfate, aluminum sulfate, Zn, Sn, Si, Nb, Ti, Zr, W, Mn, V, Ni, Al, including transition Sulfate or nitrate of metal, Nb, Ti, Zr, W or V.

The method of the invention does not use expensive metal alkoxides, but uses low-cost nitrates, sulfates or chlorides as precursors.

Secondly, the method of the present invention does not use traditional expensive surfactants as complexing agents, but uses relatively cheap industrial raw material acrylic acid.

Third, the preparation time is reduced from tens of hours to several days in traditional methods to several hours, which greatly speeds up the production cycle.

Fourth, this method has a wide range of applications. For traditional synthesis methods, CeO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , CuO, V ₂ O ₅ , NiO, ZnO, Fe ₂ O ₃ , Al ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ and SiO ₂ ) must select different surfactants (such as cationic surfactant and anionic surfactant, etc.), but the method of the present invention can only use one type of surfactant.

Fifth, the present invention does not require a sol-gel process, but calcines the precipitate formed by adding acrylic acid and other organic acids, which is essentially different from other methods.

The features of the present invention are:

1. The reaction time is short and the preparation cycle is short. The time of the mixing process of the raw materials and the reaction process of the method is relatively short, and the reaction time is generally not more than 5 hours.

2. Low cost. The price of raw materials adopted in the present invention is relatively low, and the requirements for production equipment are very simple, no high-cost equipment such as an autoclave is involved, and the cost of large-scale production is relatively low.

3. The pollution to the environment is less, and the method does not involve the use of other organic solvents except acrylic acid, and acrylic acid basically completely participates in the reaction, and no waste water and waste residue will be generated.

4. A variety of mesoporous metal oxides can be synthesized, which has good versatility. This method can synthesize Nb ₂ O ₅ , Ta ₂ O ₅ , CuO, V ₂ O ₅ , NiO, ZnO, Fe ₂ O ₃ , Al ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ and SiO ₂ etc. porous metal oxides.

4. Description of drawings

Fig. 1 is the XRD figure of the product of embodiment 1,

Fig. 2 is the pore size distribution curve of the product of embodiment 1;

5. Specific implementation

Example 1: Cobalt nitrate and acrylic acid with a stoichiometric ratio of 1:1 were mixed in a beaker for ten minutes, and the resulting precipitate was filtered, washed, put into a clay crucible, placed in a muffle furnace, and taken out after calcination at 300 degrees Celsius for five hours. , the obtained product can be properly ground to obtain mesoporous Co ₄ O ₃ . Increasing the amount of acrylic acid yielded the same results for stoichiometric ratios of 1:3 and 1:5.

Example 2: The stoichiometric ratio of aluminum trichloride and acrylic acid of 1:2 was mixed in a beaker for ten minutes, and the resulting precipitate was filtered, washed, packed into a clay crucible, placed in a muffle furnace, and heated at 300 degrees Celsius for five hours. After calcination and removal, the obtained product can be properly ground to obtain mesoporous Al ₂ O ₃ , and there is no significant difference in the heating rate of 5 or 8°C/min. Aluminum sulfate, zinc sulfate or ferrous sulfate can be used to obtain mesoporous Al ₂ O ₃ , mesoporous ZnO, and mesoporous Fe ₂ O ₃ by the above process.

Example 3: Titanium tetrachloride and acrylic acid with a stoichiometric ratio of 1:9 were mixed in a beaker for ten minutes, and the resulting precipitate was filtered, washed, packed into a clay crucible, and placed in a muffle furnace for five or five minutes at 300 or 350 degrees Celsius. After three hours of calcination, the obtained product can be properly ground to obtain mesoporous TiO ₂ , and there is no significant difference in the heating rate of 3-8°C/min. The amount of crotonic acid is the same as that of acrylic acid, and mesoporous TiO ₂ can also be obtained under the above conditions.

Cobalt nitrate, zinc sulfate or aluminum sulfate are used as raw materials to obtain mesoporous cobalt oxide, zinc oxide or aluminum oxide. However, the calcination temperature in the muffle furnace is different, and the calcination is performed at 300, 320 or 350 degrees Celsius for four hours. When nickel sulfate is used as raw material, the conditions are the same as zinc sulfate.

According to the above results, the synthetic method for preparing mesoporous metal oxides of the present invention has a wide range of applications. By controlling the reaction conditions, sulfides can be obtained from the corresponding oxides through simple calcination, the reaction conditions are simple, the cost is low, the reaction speed is fast, no complicated reaction equipment is required, the investment is small, and there is a great application prospect. It has great advantages over traditional synthetic methods.

During the reaction, add 0.5-2% polymerization inhibitor appropriately, commonly used such as methyl hydroquinone or hydroquinone.

The embodiment of other metals: as above-mentioned conditions, the result of the embodiment of strontium nitrate or strontium sulfate, manganese sulfate, zirconium sulfate, Sn, V, Nb, W is the same as embodiment 3.

Figure 1 is the XRD pattern of the product of Example 1. By comparing it with the standard spectrum of Co ₃ O ₄ (PDF file number 76-1802), it can be found that the prepared Co ₃ O ₄ has been phased and has no other impurities.

Fig. 2 is the pore size distribution curve of the product of Example 1, from which it can be seen that the pore size distribution range of the obtained product is relatively narrow, between 7-12nm.

Claims (6)

1, mesoporous metal oxide preparation method: it is characterized in that metal-salt is dissolved in the vinylformic acid, metal-salt and acrylic acid mol ratio are 1: 0.1～10 stirring 0.2-2h, difference suction filtration, and respectively wash 1-3 all over also dry with distilled water, alcohol; Dried powder is tiled in the crucible, and respectively at 200-350 ℃ of temperature roasting 3-8h, temperature rise rate all is 2-8 ℃/min in retort furnace.

2, by the described mesoporous metal oxide preparation method of claim 1: it is characterized in that putting into ultrasonic cleaning machine supersound process 3-15min and wash suction filtration again.

3, by the described mesoporous metal oxide preparation method of claim 1: it is characterized in that metal-salt is comprised transition metal, Nb, Ti, Zr, W, Al, or V, metal-salt comprises muriate, nitric acid or vitriol.

4, by the described mesoporous metal oxide preparation method of claim 1: in 50-80 ℃ baking oven, dried by the fire when it is characterized in that drying 2-5 hour.

5, by the described mesoporous metal oxide preparation method of claim 1: the pH value that it is characterized in that in reaction process, heating or reconciling solution.

6, by the described mesoporous metal oxide preparation method of claim 1: it is characterized in that described metal-salt comprises titanium tetrachloride, Xiao Suangu, zinc sulfate, Tai-Ace S 150.

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