CN103111301A - Preparation method of multiple-duct composite metal oxide - Google Patents

Abstract

The invention discloses a preparation method of a multiple-duct composite metal oxide. The preparation method comprises the following steps of: adding metal salt and citric acid to a surfactant or a segmented copolymer which is taken as a soft template and a brine shrimp egg shell which is taken as a hard template;, and stirring to obtain wet gel; drying the wet gel in a drying box, and calcining the dried gel in a muffle to obtain the multiple-duct composite metal oxide. The preparation method is low in cost, simple in process, easy to control and good in repeatability, ensures that pore size distribution is uniform and pore walls are communicated with one another, and can be widely applied to the fields of catalysis, fuel batteries and electrode materials.

Description

A kind of preparation method of multilevel porous composite metal oxide

technical field

The invention belongs to the technical field of functional materials, in particular to a method for preparing metal oxides.

Background technique

Metal oxides are widely used in lithium-ion batteries, supercapacitors, fuel cells, catalyst materials and other fields. Hierarchical pore structure has attracted more attention due to its large specific surface area, light density, large internal volume and high permeability. At present, the preparation of multi-level pore structures mostly adopts the double-template method, using polymers such as polyurethane as macroporous templates, and block copolymers or quaternary ammonium salts as mesoporous templates.

However, most of the multi-level pore structures prepared by the prior art have shortcomings such as weak periodicity of the pore structure, poor connectivity between macropores, or indistinct mesoporous structure. Artemia eggshell itself has a wide pore size distribution, and has the advantages of regular and orderly distribution of macropores, mesopores, and micropores. However, the current research on Artemia eggshells only stops at its nutritional value, water retention However, there are no reports on the structure research and structure replication of its multi-level channels.

Contents of the invention

The purpose of the present invention is to provide a low-cost, simple process, uniform pore size distribution and interconnected multi-level pore composite metal oxide preparation method. The invention mainly uses the surface active agent as the soft template and the Artemia egg shell as the hard template, and endows the LiNiCuZn composite metal oxide with the multi-level channel structure of the Artemia egg shell, thereby improving the performance of the composite metal oxide.

The preparation method of the present invention is as follows:

(1) Dissolve the chemical template in water and stir at 40-60°C at a speed of 400r/min-800r/min for 0.5-1h. The chemical template is a surfactant or a block copolymer, the surfactant is a quaternary ammonium salt surfactant, such as cetyltrimethylammonium bromide (CTAB), and the block copolymer is poly Oxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer, such as Pluronic P123, F127, F77, L62, L64, etc. The concentration of the surfactant or block copolymer is 0.001 ~ 0.03mol/L.

(2) According to the ratio of adding 0.041g~0.35g metal salt per milliliter of the above solution, add metal salt to the above solution, and continue stirring at constant temperature for 1~2h. The metal salt is Li, Ni, Cu, Zn nitrate and The mixture of acetate, the metal ion concentration of the above metal salt is 0.15mol/L~2mol/L, and the mass ratio of Li, Ni, Cu, Zn metal salt is 0.1~6:1~7:1~8:2 ~14.

(3) Clean Artemia egg shells, ball mill for 6 hours, and then use 6~12mol/L HCl, 8~18mol/L H ₂ SO ₄ , 6~14mol/L HNO ₃ , 2~6mol /L KOH soaking pretreatment, the pretreatment time is 2~6h for each substance, and drying to remove moisture.

(4) Add citric acid to the above-mentioned metal salt solution, the ratio of the molar weight of citric acid to the molar weight of metal ions is R=1~2. Then add the above-mentioned treated artemia eggshells, the ratio is to add 0.005-0.05g eggshells per milliliter of the above-mentioned metal salt solution, continue stirring until a sol is formed, and adjust the Ph value to 6-8 with ammonia water. Raise the temperature to 80-100°C and stir until a wet gel is formed.

(5) Dry the above gel in a drying oven at 80°C-100°C for 6~24h to form a xerogel.

(6) The above-mentioned dry gel is heated to 500-800°C in a muffle furnace at a rate of 1-10°C/min for calcination, and kept for 4-6 hours to prepare a multi-level porous composite metal oxide.

Compared with the prior art, the present invention has the following advantages:

1. Using natural and easy-to-obtain artemia eggshells as hard template agents, the cost is low, the operation is simple, and the repeatability is high.

2. The prepared metal oxide has a regular and orderly macropore-mesopore-micropore tertiary pore structure, with uniform pore size distribution and interconnected pore walls. This structure is conducive to the formation of continuous ion/electron transport channels, shortening the distance of ion/electron migration, increasing the active area of the reaction, and improving the catalytic activity of the material. It will have a very wide range of application values in the fields of catalysis, fuel cells, and electrode materials.

Description of drawings

Fig. 1 is the XRD pattern of the multi-level channel LiNiCuZn oxide prepared in Example 1 of the present invention.

Fig. 2 is the XRD figure of the hierarchical porous LiNiCuZn oxide prepared in Example 2 of the present invention.

Fig. 3 is the XRD figure of the hierarchical porous LiNiCuZn oxide prepared in Example 3 of the present invention.

Fig. 4 is the SEM picture of the multi-level channel LiNiCuZn oxide prepared in Example 4 of the present invention.

Detailed ways

Example 1

Dissolve 1.26g of Pluronic F127 in 100ml of water, stir at 40°C at a speed of 400r/min for 0.5h, add 0.1g of lithium acetate, 1g of nickel nitrate, 1g of copper nitrate and 2g of zinc nitrate to the above solution, and continue stirring at constant temperature for 1h; Clean Artemia egg shells, ball mill them for 6 hours, and pretreat them with 6 mol/L HCl, 8 mol/L H ₂ SO ₄ , 6 mol/L HNO ₃ , and 2 mol/L KOH. For 2 h for each substance, dry to remove water. Add 7.4263g of citric acid to the above-mentioned solution with metal salts, add 0.5g of Artemia egg shells, continue to stir to form a sol, adjust the Ph value to 6 with ammonia water, raise the temperature to 80°C, and stir until a gel is formed. The obtained gel was dried in an oven at 80° C. for 6 hours to form a xerogel. Then, the obtained xerogel is controlled at a calcining temperature of 500° C. at a heating rate of 1° C./min, and kept for 4 hours to obtain a multi-level porous LiNiCuZn composite metal oxide. As shown in Figure 1, the peaks of NiO, CuO, and ZnO at 400°C can be observed, but Li ₂ O cannot be seen.

Example 2

Stir 0.5285g CTAB in 100ml water at 50°C at a speed of 600r/min for 0.75h. Add 3.05g of lithium acetate, 4g of nickel acetate, 4.5g of copper nitrate, and 8g of zinc nitrate to the above solution, and stir at a constant temperature for 1.5h; clean the eggshells of Artemia, ball mill them for 6 hours, and then use HCl with a concentration of 9mol/L , 13mol/L of H ₂ SO ₄ , 10mol/L of HNO ₃ , and 4mol/L of KOH for pretreatment by immersion. The immersion time is 4 hours for each substance, and then dried to remove water. Add 31.8517g of citric acid and 2.35g of Artemia egg shells to the above-mentioned solution with metal salts, continue to stir to form a sol, adjust the Ph value to 7 with ammonia water, raise the temperature to 90°C, and stir until a gel is formed. The obtained gel was dried in an oven at 90° C. for 15 hours to form a xerogel. Then, the obtained xerogel is controlled to calcine at a temperature of 600° C. at a heating rate of 6° C./min, and kept for 5 hours to prepare multi-level porous LiNiCuZn oxide. As shown in Fig. 2, the peaks of NiO, CuO, and ZnO at 600°C can be observed, but Li ₂ O cannot be seen.

Example 3

Dissolve 1.093g of CTAB in 100ml of water and stir at 60°C for 1h at a speed of 800r/min. Add 6g of lithium nitrate, 7g of nickel acetate, 8g of copper acetate and 14g of zinc acetate to the above solution, and continue to stir at a constant temperature for 2 hours; clean the egg shells of Artemia, and ball mill them for 6 hours, then use HCl with a concentration of 12mol/L, 18mol /L of H ₂ SO ₄ , 14mol/L of HNO ₃ , and 6mol/L of KOH for pretreatment, soaking time is 6h for each substance, and drying to remove water. Add 46.0227g of citric acid to the above-mentioned solution with metal salts, add 5g of Artemia egg shells, continue to stir to form a sol, adjust the Ph value to 8 with ammonia water, raise the temperature to 100°C, and stir until a gel is formed. The obtained gel was dried in an oven at 100° C. for 24 hours to form a xerogel. Then, the obtained dry gel is controlled at a calcining temperature of 800° C. at a heating rate of 10° C./min, and kept for 6 hours to obtain a multi-level porous LiNiCuZn composite metal oxide. As shown in Fig. 3, the peaks of NiO, CuO, and ZnO at 800°C can be observed, but Li ₂ O cannot be seen.

Example 4

Dissolve 1.73g of Pluronic P123 in 100ml of water, and stir at 50°C at a speed of 700r/min for 0.5h. Add 0.15g of lithium acetate, 1.8g of nickel nitrate, 1.5g of copper acetate and 6g of zinc nitrate to the above solution, and continue to stir at a constant temperature for 1h; clean the eggshells of Artemia, ball mill them for 6 hours, and use 8mol/L HCl, 13mol/L H ₂ SO ₄ , 10mol/L HNO ₃ , and 4mol/L KOH were soaked for pretreatment. The soaking time was 4 hours for each substance, and dried to remove water. Add 10.717g of citric acid and 1g of Artemia eggshells to the above-mentioned solution with metal salts, continue to stir to form a sol, adjust the Ph value to 6 with ammonia water, raise the temperature to 80°C, and stir until a gel is formed. The obtained gel was dried in an oven at 80° C. for 12 hours to form a xerogel. Then, the obtained xerogel is controlled to be calcined at 700° C. at a heating rate of 5° C./min, and kept for 5 hours to obtain a multi-level porous LiNiCuZn oxide. As shown in Figure 4, the hierarchical pore structure can be observed at 700 °C.

Claims (1)

1. the preparation method of a multistage pore canal composite metal oxide, is characterized in that,

(1) chemical template is soluble in water, stir 0.5 ~ 1h take speed as 400r/min-800r/min under 40-60 ℃,

Described chemical template is surfactant or block copolymer, described surfactant is quaternary surfactant, described block copolymer is the polyoxyethylene-poly-oxypropylene polyoxyethylene triblock copolymer, and the concentration of its surfactant or block copolymer is 0.001 ~ 0.03mol/L;

(2) add the ratio of 0.041g ~ 0.35g slaine in every milliliter of mentioned solution, add slaine in mentioned solution, continue constant temperature and stir 1 ~ 2h, described slaine is the nitrate of Li, Ni, Cu, Zn and the mixture of acetate, the concentration of metal ions of above-mentioned slaine is 0.15mol/L ~ 2mol/L, and the mass ratio of Li, Ni, Cu, Zn slaine is 0.1 ~ 6:1 ~ 7:1 ~ 8:2 ~ 14

(3) halogen worm's ovum shell is cleaned up, ball milling after 6 hours, is the HCl of 6 ~ 12mol/L, the H of 8 ~ 18mol/L with concentration respectively ₂SO ₄, 6 ~ 14mol/L HNO ₃, 2 ~ 6mol/L the KOH dipping pretreatment, pretreatment time is every kind of material 2 ~ 6h, drying is removed moisture,

(4) add citric acid in the above-mentioned solution that adds slaine, the ratio of the mole of citric acid and the mole of metal ion is R=1 ~ 2, the halogen worm's ovum shell that will add again above-mentioned processing, its ratio is to add 0.005 ~ 0.05g halogen worm's ovum shell in every milliliter of above-mentioned solution that adds slaine, continuing constant temperature stirs until form colloidal sol, regulate Ph value to 6 ~ 8 with ammoniacal liquor, be warming up to 80-100 ℃, be stirred to the formation wet gel;

(5) above-mentioned gel is formed xerogel at 80 ~ 100 ℃ of drying box inner drying 6h-24h;

(6) above-mentioned xerogel is warming up to 500-800 ℃ with the speed of 1 ~ 10 ℃/min in Muffle furnace and calcines, insulation 4 ~ 6h.

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