CN103041813A - Preparation method of titanium dioxide coated iron trioxide hollow sphere - Google Patents

Abstract

The invention discloses a preparation method of titanium dioxide-coated ferric oxide hollow spheres. In the preparation process, carbon spheres are used as templates, ferric chloride is used as an iron source to synthesize ferric oxide at a relatively low temperature, and tetrabutyl titanate is used as a titanium source to synthesize titanium dioxide-coated ferric oxide hollow spheres. The method provided by the invention is simple and mild, and the reaction temperature is low, and the thickness of the titanium dioxide coating layer can be adjusted by changing the added amount of tetrabutyl titanate.

Description

A kind of preparation method of titanium dioxide coated ferric oxide hollow sphere

technical field

The invention relates to an inorganic semiconductor composite material, in particular to a preparation method of titanium dioxide-coated ferric oxide hollow spheres.

Background technique

Due to the advantages of good chemical stability, wear resistance, low cost, and direct use of sunlight, nano-TiO ₂ has broad application prospects in photoelectric conversion, chemical synthesis, and photocatalytic oxidation of environmental pollutants. TiO ₂ photocatalyst has a wide band gap (Eg=3.2 eV, λ=387 nm), and only under the excitation of ultraviolet rays with λ<387 nm, electrons in the valence band can transition to the conduction band to form photogenerated electrons and holes. The recombination of electrons and holes generated by light excitation leads to very low photon quantum efficiency. In order to overcome these shortcomings, people have conducted a lot of in-depth research on improving its visible light catalytic activity and catalytic efficiency, and effectively using solar energy. TiO ₂ is modified to extend the response spectrum of TiO ₂ to visible light, effectively inhibit the recombination of electrons and holes, and improve the photocatalytic efficiency of nano-TiO ₂ .

Transition metal ion doping can introduce defect positions in the TiO ₂ lattice or change the crystallinity, thereby affecting the recombination of electrons and holes, and at the same time may form doping energy levels to expand the range of light absorption wavelengths. Fe ₂ O ₃ as a It is a semiconductor material with a narrow bandgap (Eg=2.2 eV, λ=563 nm), its absorption spectrum matches the solar spectrum, and it can directly use solar energy; however, the lifetime of Fe ₂ O ₃ holes is short, and it is easy to Photocorrosion occurs, so combining the advantages of Fe ₂ O ₃ and TiO ₂ , modifying TiO ₂ with Fe ³⁺ or Fe ₂ O ₃ has become a research hotspot in recent years.

Contents of the invention

The object of the present invention is to provide a method for preparing titanium dioxide-coated ferric oxide hollow spheres. The thickness of the titanium dioxide coating layer can be adjusted by changing the amount of tetrabutyl titanate added. The titanium dioxide-coated ferric oxide prepared by this method The diiron hollow spheres are uniform in size, with a diameter of 850-1100 nm, and the thickness of the titanium dioxide-coated shell is between 50-100 nm.

The preparation method of titanium dioxide-coated ferric oxide hollow spheres provided by the present invention specifically comprises the following steps:

(1) Dissolve glucose in deionized water to form a solution with a mass concentration of 0.15–0.20 g/mL, and transfer the solution into a reactor for hydrothermal reaction at a temperature of 160–180°C and a reaction time of 6–8 h , centrifuged and dried to obtain a carbon sphere template;

(2) Ferric chloride is dissolved in the mixed solution of absolute ethanol and deionized water, wherein the volume ratio of absolute ethanol and deionized water is 6: 1, and the concentration of iron ions is 0.05 ~ 0.1 mol/L;

(3) urea is dissolved in the above solution, stirred to dissolve, wherein the mol ratio of urea to iron ion is 10: 1;

(4) Add the carbon sphere template obtained in step (1) into the solution obtained in step (3), the molar ratio of carbon spheres to iron ions is 8: 1, mix well and transfer to an oven at 60~80°C for 48 hours , centrifugal drying;

(5) Dissolve the sample obtained in step (4) in a mixed solution of absolute ethanol and deionized water, wherein the volume ratio of absolute ethanol and deionized water is 6: 1, and tetrabutyl titanate is added to the above solution , stir evenly, wherein the molar ratio of titanium ions to iron ions is 1: 1 ~ 1: 2;

(6) Calcining the sample obtained in step (5) at 450-500° C. for 2 hours to obtain titanium dioxide-coated ferric oxide hollow spheres.

Description of drawings

Fig. 1 is the TEM figure of the ferric oxide hollow sphere prepared in Example 1.

Figure 2 is the XRD pattern of the TiO2-coated Fe2O3 hollow spheres prepared in Example 2, in which the mark * is the characteristic peak of TiO2 and ♦ is the characteristic peak of Fe2O3.

FIG. 3 is a TEM image of titanium dioxide-coated ferric oxide hollow spheres prepared in Example 2. FIG.

FIG. 4 is a TEM image of titanium dioxide-coated ferric oxide hollow spheres prepared in Example 3. FIG.

Detailed ways

The present invention will be further described below through specific embodiments. It can be seen from technical knowledge that the present invention can also be described by other solutions that do not depart from the technical features of the present invention. Therefore, all changes within the scope of the present invention or equivalent to the scope of the present invention are accepted. The present invention includes.

Example 1

Dissolve 6 g of glucose in 40 mL of deionized water to form a solution with a mass concentration of 0.15 g/mL, transfer the solution into a reaction kettle for hydrothermal reaction at a temperature of 180 °C, and a reaction time of 6 h, then centrifuge and dry to obtain Carbon sphere template; Dissolve 0.82 g of ferric chloride in a mixed solution of 56 mL of absolute ethanol and deionized water, wherein the volume ratio of absolute ethanol and deionized water is 6: 1, and dissolve 1.8 g of urea in the above solution , stirred until dissolved, added 0.3 g carbon sphere template to the above solution, mixed evenly, transferred to an oven at 60°C for 48 hours, and was centrifuged and dried. The obtained sample was calcined at 450°C for 2 hours to remove the carbon sphere template, and Fe ₂ O ₃ hollow spheres were obtained. The product of this example (Fe ₂ O ₃ hollow spheres) was subjected to transmission electron microscopy to observe its microscopic morphology, and the results are shown in Figure 1 , the prepared Fe ₂ O ₃ sample is a hollow spherical structure with a uniform size and a diameter of about 800-1000 nm.

Example 2

Dissolve 8 g of glucose in 40 mL of deionized water to form a solution with a mass concentration of 0.2 g/mL, transfer the solution into a reactor for hydrothermal reaction at a temperature of 160 °C, and a reaction time of 8 h, then centrifuge and dry to obtain Carbon sphere template; Dissolve 0.82 g of ferric chloride in a mixed solution of 56 mL of absolute ethanol and deionized water, wherein the volume ratio of absolute ethanol and deionized water is 6: 1, and dissolve 1.8 g of urea in the above solution , stirred until dissolved, added 0.3 g of carbon sphere templates to the above solution, mixed evenly, transferred to an oven at 60°C for 48 hours, and centrifuged to dry. The obtained samples were calcined at 500°C for 2 hours to remove the carbon sphere templates to obtain Fe ₂ O ₃ hollow spheres, the size and structure are similar to the results obtained in Example 1.

Example 3

0.48 g of the sample prepared in Example 1 without heat treatment was dispersed in a mixed solution of 56 mL of absolute ethanol and deionized water, wherein the volume ratio of absolute ethanol and deionized water was 6: 1; 0.35 mL Tetrabutyl titanate was added to the above solution, so that the molar ratio of titanium ions to iron ions was 1: 2, stirred evenly, the solution was kept in an oven at 60°C for 48 hours, and dried by centrifugation, and the obtained sample was roasted at 450°C for 2 Hours, titanium dioxide-coated ferric oxide hollow spheres were obtained, and the X-ray powder diffraction results of the product of this example (titanium dioxide-coated ferric oxide hollow spheres) were shown in Figure 2. The mark * in the figure is the characteristic peak of titanium dioxide , ♦ is the characteristic peak of ferric oxide. The prepared sample has the characteristic peaks of Fe ₂ O ₃ and TiO ₂ at the same time, which is consistent with the standard PDF card. The product is a composite structure of Fe ₂ O ₃ and TiO ₂ . Transmission electron microscopy was carried out to observe its microscopic morphology. As shown in Figure 3, the product is a core-shell hollow structure, and the thickness of the titanium dioxide coating layer is about 50 nm.

Example 4

0.48 g of the sample prepared in Example 2 without heat treatment was dispersed in a mixed solution of 56 mL of absolute ethanol and deionized water, wherein the volume ratio of absolute ethanol and deionized water was 6: 1; 0.7 mL Tetrabutyl titanate was added to the above solution, so that the molar ratio of titanium ions to iron ions was 1: 1, stirred evenly, the solution was kept in an oven at 60°C for 48 hours, and dried by centrifugation, and the obtained sample was roasted at 450°C for 2 Hours, titanium dioxide-coated ferric oxide hollow spheres were obtained, and the product of this example (titanium dioxide-coated ferric oxide hollow spheres) was subjected to a transmission electron microscope to observe its microscopic morphology. As shown in Figure 4, the product is a core-shell It has a hollow spherical structure, and the thickness of the titanium dioxide coating layer is about 100 nm.

Claims (4)

1. the preparation method of a coated by titanium dioxide di-iron trioxide hollow ball is characterized in that may further comprise the steps:

(1) preparation carbon ball template;

(2) ferric sesquichloride is dissolved in the mixed solution of absolute ethyl alcohol and deionized water, the concentration of iron ion is 0.05 ~ 0.1 mol/L;

(3) urea is dissolved in the mentioned solution, is stirred to dissolving, wherein the mol ratio of urea and iron ion is 10:1;

(4) the carbon ball template of step (1) gained is added in the solution of step (3) gained, the mol ratio of carbon ball and iron ion is 8:1, transfers in the baking oven 60 ~ 80 ℃ after mixing and is incubated 48 hours, centrifugal drying;

(5) with the sample dissolution of step (4) gained in the mixed solution of absolute ethyl alcohol and deionized water, butyl titanate is added in the mentioned solution, stir, wherein the mol ratio of titanium ion and iron ion is 1:1 ~ 1:2;

(6) with the sample of step (5) gained 450 ~ 500 ℃ of roastings 2 hours, obtain coated by titanium dioxide di-iron trioxide hollow ball.

2. the preparation method of a kind of coated by titanium dioxide di-iron trioxide hollow ball as claimed in claim 1, it is characterized in that: the step of described preparation carbon ball template is: glucose is dissolved in the deionized water, forming mass concentration is the solution of 0.15 ~ 0.20 g/mL, to carry out hydro-thermal reaction in this solution immigration reactor, temperature is 160 ~ 180 ℃, reaction time is 6 ~ 8 h, and centrifugal drying obtains the carbon ball template.

3. the preparation method of a kind of coated by titanium dioxide di-iron trioxide hollow ball as claimed in claim 1, it is characterized in that: the volume ratio of described absolute ethyl alcohol and deionized water is 6:1.

4. the preparation method of a kind of coated by titanium dioxide di-iron trioxide hollow ball as claimed in claim 1, it is characterized in that: described coated by titanium dioxide di-iron trioxide hollow ball size uniform, diameter is at 850 ~ 1100 nm, and the shell thickness of coated by titanium dioxide is between 50 ~ 100 nm.

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