CN1607611A - Sol-gel preparation method of cobalt ion-doped titanium dioxide ferromagnetic material - Google Patents

Abstract

The invention relates to a preparation technology of a cobalt ion-doped titanium dioxide ferromagnetic material, in particular to a chemical preparation technology for preparing cobalt ion-doped titanium dioxide particles and films by a sol-gel method. Compared with conventional physical preparation methods, the cobalt ion-doped titanium dioxide ferromagnetic particles and film components prepared by the sol-gel method provided by the present invention are uniform, and no nano-cobalt metal particles are found to generate (the accompanying drawing shows 500 ℃ calcined 5mol % cobalt ion-doped titanium dioxide thin film XRD spectrum), this method is simple and easy to operate, the raw material is easy to get and the cost is low, and it is beneficial to industrial production.

Description

Sol-gel preparation method of cobalt ion-doped titanium dioxide ferromagnetic material

Technical Field This field relates to a cobalt ion-doped titanium dioxide ferromagnetic material and its preparation technology, in particular to a preparation technology for cobalt ion-doped titanium dioxide ferromagnetic particles and films by sol-gel method.

Background technology Titanium dioxide is a very important semiconductor functional material, which has broad application prospects in the technical fields of catalysis, optoelectronics, and dielectrics. In particular, in 2001, Y. Matsumoto et al. first discovered that cobalt ion-doped titanium dioxide films have both ferromagnetic and semiconducting properties at room temperature, which greatly promoted the development of quantum storage technology relying on electron spin. However, the current technology for preparing cobalt ion-doped titania materials mainly focuses on physical methods, such as laser molecular beam epitaxy deposition method, magnetron ion sputtering method and so on. These methods can grow uniaxially oriented films, and the films have good room-temperature ferromagnetic and semiconducting properties. However, the study found that there are more or less nano-cobalt particles in the cobalt ion-doped titanium dioxide film prepared by physical methods. Its existence not only affects the semiconducting properties of the film, but also creates ambiguity about the source of ferromagnetism. In addition, the technology required by the physical method is complex and expensive.

Summary of the invention In order to overcome the disadvantages of cobalt ion-doped titanium dioxide materials prepared by physical methods, the present invention provides a chemical method for preparing cobalt ion-doped titanium dioxide materials with ferromagnetic and semiconducting properties by using a sol-gel method. The particles prepared by this method and The composition of the thin film is uniform, no nano-cobalt metal particles are found, the method is simple and easy to operate, and the raw materials are readily available and cost-effective.

Description of drawings

Fig.1 XRD patterns of 5mol% cobalt ion-doped titania particles calcined at 500℃

Fig.2 XRD patterns of 5mol% cobalt ion-doped titania particles calcined at 700℃

Specific implementation methods The raw materials used are: chemically pure n-butyl titanate, analytically pure anhydrous ethanol, analytically pure cobalt nitrate or cobalt chloride, and secondary deionized water. A certain amount of n-butyl titanate and a certain amount of absolute ethanol are uniformly mixed as the first component; a certain amount of cobalt nitrate or cobalt chloride and a small amount of deionized water are dissolved in a certain amount of absolute ethanol as the first component. second component. Under stirring, slowly drop the second component into the first component to obtain a dark blue solution; then leave the system for 2 hours to obtain a transparent sol. The sol is divided into two parts, one of which is left at room temperature for 24 hours to 72 hours to obtain a gel, and the gel is vacuum-dried at 70°C to obtain a xerogel, and the ground gel powder of the xerogel is placed in a high-temperature resistor The crystalline cobalt ion-doped titanium dioxide particle sample can be obtained by calcining at a certain temperature for several hours in a furnace. Immerse the glass plate or quartz glass plate soaked in ethanol or acetone and ultrasonically cleaned in another part of the sol, and obtain a cobalt ion-doped titanium dioxide film on the glass plate or quartz glass plate by dipping-pulling method; The film is kept at a certain humidity and temperature for 24 hours to evaporate the solvent while completing the gel, and put it into a high-temperature resistance furnace for calcination at a certain temperature for several hours to obtain a crystallized cobalt ion-doped titanium dioxide film sample.

The realization process of the present invention and the performance of material are explained by embodiment and accompanying drawing:

Embodiment one:

Mix 15 ml of n-butyl titanate with 20 ml of absolute ethanol as the first component; dissolve 0.59 g of cobalt nitrate and 0.2 ml of deionized water in 15 ml of absolute ethanol as the second component . Under stirring, slowly drop the second component into the first component to obtain a dark blue solution; then let the system stand for 2 hours to obtain a transparent sol, which can be obtained at a temperature of 15-35°C and a humidity of 30 Under the condition of -60%, let it stand for 24 hours to 72 hours to obtain a gel. The gel is vacuum dried at 70°C to obtain a dry gel. The ground gel powder of the dry gel is placed in a high-temperature resistance furnace at a temperature of 500°C. The crystalline cobalt ion-doped titanium dioxide particle sample can be obtained by calcining at low temperature for 4 hours. Figure 1 shows the XRD patterns of calcined cobalt ion-doped titania film particles. Figure 1 shows the XRD pattern of calcined cobalt ion-doped titania particles.

Embodiment two:

Mix 15 ml of n-butyl titanate with 20 ml of absolute ethanol as the first component; dissolve 0.59 g of cobalt nitrate and 0.2 ml of deionized water in 15 ml of absolute ethanol as the second component . Under stirring, slowly drop the second component into the first component to obtain a dark blue solution; then let the system stand for 2 hours to obtain a transparent sol. Immerse the plate or quartz glass sheet in the above-mentioned sol for 1 minute, and pull the glass plate or quartz glass sheet at a speed of 10 cm/min to obtain a cobalt ion-doped titanium dioxide film; Keep the condition of 30-60% for 24 hours to volatilize the solvent while completing the gel, and put it into a high-temperature resistance furnace for calcination at 500° C. for 2 hours to obtain a crystallized cobalt ion-doped titanium dioxide film sample.

Embodiment three:

Mix 15 ml of n-butyl titanate with 20 ml of absolute ethanol as the first component; dissolve 0.59 g of cobalt nitrate and 0.2 ml of deionized water in 15 ml of absolute ethanol as the second component . Under stirring, slowly drop the second component into the first component to obtain a dark blue solution; then let the system stand for 2 hours to obtain a transparent sol. Stand still for 24 hours to 72 hours at a humidity of 30-60% to obtain a gel, dry the gel under vacuum at 70°C to obtain a xerogel, and put the ground gel powder of the xerogel into a high-temperature resistance furnace Calcined at 700°C for 4 hours to obtain crystallized cobalt ion-doped titanium dioxide particle samples. Figure 2 shows the XRD pattern of calcined cobalt ion-doped titania particles.

Embodiment four:

Mix 15 ml of n-butyl titanate with 20 ml of absolute ethanol as the first component; dissolve 0.59 g of cobalt nitrate and 0.2 ml of deionized water in 15 ml of absolute ethanol as the second component point. Under stirring, slowly drop the second component into the first component to obtain a dark blue solution; then let the system stand for 2 hours to obtain a transparent sol. Immerse the plate or quartz glass sheet in the above-mentioned sol for 1 minute, and pull the glass plate or quartz glass sheet at a speed of 10 cm/min to obtain a cobalt ion-doped titanium dioxide film; Keep the solvent at 30-60% for 24 hours to evaporate the solvent while completing the gel, and put it into a high-temperature resistance furnace for calcination at 700° C. for 2 hours to obtain a crystallized cobalt ion-doped titanium dioxide film sample.

Claims (6)

1. A sol-gel preparation method of cobalt ion-doped titanium dioxide ferromagnetic material, its main feature is that the doping process starts from the solution and passes through normal temperature sol-gel reaction and calcination to realize the uniform doping of cobalt ions of titanium dioxide to prepare ferromagnetic materials particles and films. 2. the sol-gel preparation method of cobalt ion-doped titanium dioxide ferromagnetic material as claimed in claim 1 is characterized in that titanium source is titanium alkoxide (as n-butyl titanate, propyl titanate, ethyl titanate) or titanium tetrachloride; cobalt ion doping is achieved with cobalt nitrate or cobalt chloride. 3. The sol-gel preparation method of the cobalt ion-doped titanium dioxide ferromagnetic material as claimed in claim 1, characterized in that the preparation temperature of the sol-gel is 15-35° C. and the humidity is 30-60%. 4. the sol-gel preparation method of cobalt ion-doped titania ferromagnetic material as claimed in claim 1 is characterized in that glass plate or quartz glass sheet soaked in advance with ethanol or acetone and ultrasonic cleaning is immersed in the above-mentioned sol, A cobalt ion-doped titanium dioxide film is obtained on a glass plate or a quartz glass plate by dipping-pulling method. 5. The sol-gel preparation method of cobalt ion-doped titanium dioxide ferromagnetic material as claimed in claim 1, characterized in that the heat treatment temperatures for obtaining anatase and rutile granular materials are 500°C and 700°C respectively, and the time is 4 hours. 6. The sol-gel preparation method of cobalt ion-doped titanium dioxide ferromagnetic material as claimed in claim 1, characterized in that the heat treatment temperature for obtaining anatase or rutile thin film material is 500°C and 700°C, and the time is 2 hours.

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