CN100455517C - Preparation method of nanotube titanate - Google Patents

Abstract

The preparation method of nanotube titanate is to mix nitrate and nanotube sodium titanate powder evenly in a molar ratio of 5-100:1, melt and react at 50-450°C for 3-48h, cool and wash, and remove unreacted nitric acid Salt, dried nanotube titanate. The nitrate is lithium nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, silver nitrate, nickel nitrate, thallium nitrate, copper nitrate, zinc nitrate or cobalt nitrate. The precursor nanotube sodium titanate used for the reaction is prepared by reacting titanium dioxide, metatitanic acid or titanate with 20-80wt% NaOH aqueous solution at 100-140°C for 12-72h, washing away NaOH with water, filtering and drying. The invention prepares nanotube titanate with high specific surface through melt exchange.

Description

Preparation method of nanotube titanate

technical field

The invention relates to a new method for preparing titanates with various nanotube structures by using nanotube sodium titanate as a precursor-melting exchange method.

Background technique

Titanates have attracted much attention due to their wide range of uses and special properties. For example, barium titanate is a good ferroelectric material and dielectric, potassium titanate fiber can be used as ion exchange material, dielectric material, friction material, reinforcement material, etc., and lithium titanate is a new generation of lithium ion Electrode materials for batteries. In recent years, with the development of nanotechnology, titanates with one-dimensional nanostructures have received widespread attention. Compared with micron-sized titanate materials, they have a large specific surface area, so they are used as lithium battery electrode materials, catalysts or catalysts. There is great potential for development in the fields of carrier materials, ion exchange materials and composite material reinforcements. At present, nanotube sodium titanate has been widely studied because of its unique tubular structure. The existing preparation methods include sintering, hydrothermal and low-temperature reflux methods, etc., but these methods cannot be used to prepare lithium titanate, potassium titanate, Rubidium titanate, cesium titanate, silver titanate, nickel titanate, thallium titanate, copper titanate, zinc titanate, cobalt titanate, etc.

Contents of the invention

The purpose of the present invention is to provide a method for preparing nanotube titanate with high specific surface area through melt exchange.

In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: the method for preparing nanotube titanate, mixing nitrate and nanotube sodium titanate powder uniformly in a molar ratio of 5-100:1, and melting and reacting at 50-450°C for 3- After 48 hours (hour, the same below), cool and wash to remove unreacted nitrate, and dry to obtain nanotube titanate.

The nitrate is lithium nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, silver nitrate, nickel nitrate, thallium nitrate, copper nitrate, zinc nitrate or cobalt nitrate.

The precursor nanotube sodium titanate used in the reaction is made of titanium dioxide, metatitanic acid or titanate and 20-80wt% (weight percent concentration) NaOH aqueous solution at 100-140 ° C for 12-72h, then washes off NaOH with water, filters, Made dry.

The melt exchange reaction equation is:

Na ₂ Ti ₂ O ₄ (OH) ₂ +xM(NO ₃ ) _y →M _x Ti ₂ O ₄ (OH) ₂ +2NaNO ₃

Where: M=Li, K, Rb, Cs, Ag, Tl, Ni, Cu, Zn, Co, etc.; x=2, y=1 or x=1, y=2.

The invention can synthesize a large amount of nanotube titanates by using cheap titanium-containing compounds as raw materials under low temperature conditions, and the specific surface area is increased so that its electrical, catalytic and other properties are improved. The inner diameter of the nanotube titanate of the present invention is about 4-10nm, the outer diameter is 10-16nm, the length is in the range of 10nm-100μm, and it is tubular.

The invention has cheap and non-toxic raw materials, low reaction temperature, simple procedure, easy operation and easy large-scale production, and is a simple new method for preparing titanate with high specific surface area.

Description of drawings

Fig. 1 is the electron microscope picture (Japan Electronics (JEOL) JEM-100CX II type transmission electron microscope (TEM) of precursor nanotube sodium titanate used in the present invention, and accelerating voltage is 100kV, and sample preparation adopts dehydrated alcohol ultrasonic dispersion and then drips Air dry on copper grid with carbon film). It can be seen that the diameter of the nanotube sodium titanate is uniform, the inner diameter is about 4-6nm, the outer diameter is about 8-10nm, and the length is about several hundred nanometers;

Fig. 2 is the electron microscope picture (electron microscope and test condition are the same as above) of nanotube lithium titanate obtained in the present invention, the tube diameter of nanotube lithium titanate is uniform, and inner diameter is about 4～6nm, and outer diameter is about 8～10nm, and length is about 100nm;

Fig. 3 is the electron micrograph of gained nanotube potassium titanate of the present invention (electron microscope and test condition are the same as above), and the morphology feature of nanotube potassium titanate is similar to that of nanotube sodium titanate;

Fig. 4 is the electron micrograph of the gained nanotube nickel titanate of the present invention (electron microscope and test condition are the same as above), the pipe diameter of nanotube nickel titanate is even, and inner diameter is about 4～6nm, and outer diameter is about 8～10nm, and length is relatively long. Inhomogeneity, 10-200nm;

)，纳米管钛酸钠的结构与层状结构的Li₂Ti₂O₅·H₂O和H₂Ti₂O₅·H₂O结构相似，属正交晶系，其晶格常数为：a₀＝19.26

，b₀＝3.78，c₀＝3.00

Fig. 5 is the X-ray diffraction pattern (X'PertPro type X-ray powder diffractometer (XRD) of Holland PHILIPS of gained nanotube titanium sodium of the present invention, voltage 40kv electric current 40mA, radiation source is CuK α I, λ=1.54056

), the structure of nanotube sodium titanate is similar to that of Li ₂ Ti ₂ O ₅ ·H ₂ O and H ₂ Ti ₂ O ₅ ·H ₂ O in layered structure. It belongs to the orthorhombic crystal system, and its lattice constant is: a ₀ =19.26

, b ₀ =3.78 , c ₀ =3.00

Fig. 6 is the X-ray diffractogram (X-ray diffractometer and test condition are the same as above) of nanotube titanium lithium obtained in the present invention, the structure of nanotube lithium titanate is obviously different from that of nanotube sodium titanate, and it contains two different crystal forms Substance: Li ₂ Ti ₂ O ₄ with cubic spinel structure and Li _x TiO ₂ with anatase structure (x<0.1);

Fig. 7 is the X-ray diffraction diagram of nanotube titanium potassium obtained in the present invention (X-ray diffractometer and test conditions are the same as above), which is similar to nanotube sodium titanate and belongs to the orthorhombic crystal system.

Detailed ways

Example 1. Take 3g of _TiO2 anatase and slowly add it into a polytetrafluoroethylene container filled with 150ml of 10M NaOH aqueous solution, control the temperature at 120°C, stir and add a reflux condenser to react for 24h. After 24 hours, the reacted mixture was cooled and settled, and washed until the pH value was about 12, filtered and dried to obtain the precursor nanotube sodium titanate.

Lithium nitrate crystals and dry precursor nanotube sodium titanate are uniformly mixed at a lithium-sodium molar ratio of 10:1, and the mixture is allowed to react at 260°C for 3 hours, cooled to room temperature, washed, and dried to obtain nanotube titanate lithium.

Example 2. Take 3g of _TiO2 anatase, slowly add it into a polytetrafluoroethylene container containing 150ml of 10M NaOH solution, control the temperature at 100°C, stir and add a reflux condenser, and react for 12h. After 12 hours, the reacted mixture was cooled and settled, washed by sedimentation until the pH value was about 12, filtered and dried to obtain the precursor nanotube sodium titanate.

Mix potassium nitrate crystals and dry precursor nanotube sodium titanate uniformly at a potassium-sodium molar ratio of 10:1, let the mixture react at 360°C for 48 hours, cool to room temperature, wash, and dry to obtain nanotube titanate potassium.

Example 3. Take 3g of _TiO2 anatase and slowly add it into a polytetrafluoroethylene container filled with 150ml of 5M NaOH solution, control the temperature at 140°C, stir and add a reflux condenser to react for 72h. After 72 hours, the reacted mixture was cooled and settled, washed by sedimentation until the pH value was about 12, filtered and dried to obtain the precursor nanotube sodium titanate.

Mix silver nitrate crystals and dry precursor nanotube sodium titanate uniformly at a silver-to-sodium molar ratio of 5:1, let the mixture react at 220°C for 6 hours, cool to room temperature, wash, and dry to obtain nanotube titanate silver.

Example 4. Take 3g of _TiO2 anatase, slowly add it into a polytetrafluoroethylene container containing 150ml of 10M NaOH solution, control the temperature at 110°C, stir and add a reflux condenser, and react for 24h. After 24 hours, the reacted mixture was cooled and settled, and washed until the pH value was about 12, filtered and dried to obtain the precursor nanotube sodium titanate.

Mix nickel nitrate crystals and dry precursor nanotube sodium titanate uniformly at a nickel-sodium molar ratio of 10:1, let the mixture react at 100°C for 6 hours, cool to room temperature, wash, and dry to obtain nanotube titanate nickel.

Claims (2)

1, method for preparing Nano tube of titanate is characterized in that, with nitrate and nanotube sodium titanate powder 5-100 in molar ratio: 1 mixes, in 50-450 ℃ of frit reaction 3-48h, the nitrate of not participating in reaction is removed in cooling, washing, the dry Nano tube of titanate that gets; Described nitrate is lithium nitrate, saltpetre, rubidium nitrate, cesium nitrate, Silver Nitrate, nickelous nitrate, thallium trinitrate (TTN), cupric nitrate, zinc nitrate or Xiao Suangu.

2, method for preparing Nano tube of titanate according to claim 1, it is characterized in that, the nanotube sodium titanate that is used to react is by titanium dioxide, metatitanic acid or titanic acid ester and 20-80wt%NaOH aqueous solution water flush away NaOH behind 100-140 ℃ of reaction 12-72h, and filtration, drying are made.

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