CN102600819B - Porous titanium dioxide photocatalyst film and preparation method thereof - Google Patents

Abstract

The invention discloses a porous titanium dioxide photocatalytic film and a preparation method thereof. The substrate participates in the oxidation reaction while using an ionic liquid as a template agent and controlling the reaction rate, so that a pure anatase phase titanium oxide film can be directly obtained on the surface of a titanium sheet. The steps are as follows: prepare a mixed solution of hydrogen peroxide solution and ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate; immerse the metal titanium sheet in the reaction solution, and place it in an oven at 80°C for several hours; The titanium dioxide film can be obtained by taking out the titanium sheet and firing it. The invention has easy-to-obtain raw materials, simple process, easy control of conditions, short preparation period and easy scale-up. The prepared pure anatase structure titanium dioxide film has high crystallinity and high purity, is firmly combined with the substrate, has good stability, and can be used repeatedly.

Description

A kind of porous titanium dioxide photocatalytic thin film and preparation method thereof

technical field

The invention belongs to the technical field of semiconductor photocatalyst preparation, and in particular relates to a porous titanium dioxide photocatalytic film and a preparation method thereof.

Background technique

While the rapid development of world industry has provided people with rich material life, it has also brought many environmental problems. The discharge of the three wastes (waste water, waste residue, waste gas) in industrial production destroys the ecological balance, pollutes the environment, and seriously threatens people's healthy life. Among them, dye wastewater is one of the industrial wastewater that is difficult to degrade at present. The discharge of printing and dyeing wastewater accounts for about one tenth of the total discharge of industrial wastewater. ecological environment.

Semiconductor photocatalysis technology can degrade a variety of toxic and harmful pollutants due to its strong oxidation ability. At the same time, it is environmentally friendly, can use solar energy, mild reaction conditions, and low cost. widespread attention. Among them, _TiO2 material has become the photocatalyst with the most application potential due to its high photocatalytic activity, stable properties, non-toxicity and cheap materials. Compared with powder catalysts, TiO ₂ photocatalytic thin films can avoid the loss and energy waste caused by the separation of catalysts and reactants during practical application, so they have better application value. However, the existing titanium oxide thin film preparation technology still has disadvantages such as relatively complicated preparation process, difficult scale-up, low crystallinity, and poor bonding firmness between the film and the substrate.

Contents of the invention

The purpose of the present invention is to provide a porous titanium dioxide photocatalytic film and its simple, low-cost preparation method and application in view of the defects existing in the prior art and market demand.

The preparation method of the porous titanium dioxide photocatalytic film of the present invention comprises the following steps:

The polished titanium sheet is soaked in a mixed solution composed of hydrogen peroxide and ionic liquid 1-butyl-3-methyl-imidazolium tetrafluoroborate, the concentration of hydrogen peroxide in the mixed solution is 10-15wt%, and the ionic liquid 1-butyl The concentration of base-3-methyl-imidazolium tetrafluoroborate is 0.1-0.5wt%, and it is kept at a constant temperature of 80°C-100°C for 8-10h, washed, and then baked at 450°C-500°C for 1-20 hours. 1.1h.

The concentration of hydrogen peroxide in the mixed solution is preferably 15 wt%, and the concentration of the ionic liquid 1-butyl-3-methyl-imidazolium tetrafluoroborate is preferably 0.2 wt%.

The porous titanium dioxide photocatalytic thin film of the present invention can be obtained through the above technical scheme, the thin film is combined with the titanium substrate to form a porous flower-like microsphere structure, and its crystal form is anatase.

The principle of the present invention is to use the template effect of ionic liquid and effectively control the reaction rate to directly obtain a pure anatase titanium dioxide film on the surface of the titanium sheet by participating in the oxidation reaction of the substrate.

Compared with the prior art, the present invention has the following advantages and outstanding effects: the chemical reagents used in the present invention are commonly used reagents, cheap and easy to obtain; the preparation process is simple, the operation is convenient, and the structure is easy to control; the prepared titanium dioxide film and The substrate is firmly bonded, the catalytic efficiency is high, the photocatalytic activity is stable, and the service life is long.

Description of drawings

Fig. 1 is the XRD spectrum of the sample prepared in embodiment 1.

FIG. 2 is a scanning electron micrograph of the sample prepared in Example 1.

Fig. 3 is the UV-vis DRS collection of spectra of the sample comparison that embodiment 1 and embodiment 8 make.

Fig. 4 is a comparison of the photocatalytic activity of the titanium oxide films prepared in Examples 1-9.

Fig. 5 is the life test result of the sample prepared in Example 1.

Detailed ways

Below in conjunction with specific embodiment, further illustrate the present invention.

The sample obtained in the following examples is characterized by the following means: the X-ray diffraction pattern measured by the Rigaku D/Max-RB type X-ray diffractometer is used to analyze the structure of the sample; Morphology and structure; MC-2530 ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) was used to analyze the light absorption properties.

Example 1

Use sandpaper to smooth the surface of the titanium sheet with a size of 42 ^cm2 to remove the surface oxide layer; use a 1:1 volume ratio of ethanol and isopropanol solution to ultrasonically wash, then ultrasonically wash with deionized water, and finally blow with _N2 to dry.

The treated titanium sheet is soaked in 50mL 15wt% H ₂ O ₂ In the mixed solution of 0.10mL ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (the concentration of hydrogen peroxide in the mixed solution is 15.0wt% , the concentration of ionic liquid 1-butyl-3-methyl-imidazolium tetrafluoroborate is 0.2wt%), placed in an oven and reacted at 80°C for 8h. The reacted titanium sheet was rinsed with deionized water three times, dried at 100°C, and then calcined at 450°C for 1 hour to obtain the target product.

Fig. 1 is an X-ray diffraction spectrum of the sample prepared in this example, from which it can be determined that the thin film on the surface of the obtained sample is anatase TiO ₂ .

Fig. 2 is the SEM photograph of the sample prepared in this embodiment, it can be seen from the photograph that the thin film on the surface of the obtained sample has a porous structure with flower-like microspheres, and the diameter of the microspheres is about 300 nm.

Example 2

The ionic liquid consumption is changed into 0.05mL, and all the other contents are the same as described in Example 1 (the concentration of hydrogen peroxide in the mixed solution is 15.0wt%, the concentration of ionic liquid 1-butyl-3-methyl-imidazole tetrafluoroborate is 0.1wt%). From the X-ray diffraction pattern of the sample prepared in this embodiment, it can be confirmed that the thin film on the surface of the obtained sample is anatase TiO ₂ , and it is known from the SEM photo that it has a porous random sheet structure.

Example 3

The ionic liquid consumption is changed into 0.15mL, and all the other contents are the same as described in Example 1 (the concentration of hydrogen peroxide in the mixed solution is 15.0wt%, the concentration of ionic liquid 1-butyl-3-methyl-imidazole tetrafluoroborate is 0.4wt%). From the X-ray diffraction pattern of the sample prepared in this example, it can be confirmed that the thin film on the surface of the obtained sample is anatase TiO ₂ . From the SEM photo, it can be seen that it has a porous structure with flower-shaped microspheres, and the diameter of the microspheres is about 1 μm.

Example 4

The ionic liquid consumption is changed into 0.20mL, and all the other contents are the same as described in Example 1 (the concentration of hydrogen peroxide in the mixed solution is 15.0wt%, the concentration of ionic liquid 1-butyl-3-methyl-imidazole tetrafluoroborate is 0.5wt%). From the X-ray diffraction pattern of the sample prepared in this example, it can be confirmed that the thin film on the surface of the obtained sample is anatase TiO ₂ . From the SEM photo, it can be seen that it has a porous structure with flower-shaped microspheres, and the diameter of the microspheres is about 2 μm.

Example 5

The reaction time was changed to 4h, and the remaining contents were the same as those described in Example 1. From the X-ray diffraction pattern of the sample prepared in this example, it can be confirmed that the thin film on the surface of the obtained sample is anatase TiO ₂ , and it is known from the SEM photo that it has a porous structure and no flower-shaped microspheres.

Example 6

The reaction time was changed to 6h, and the remaining contents were the same as those described in Example 1. From the X-ray diffraction pattern of the sample prepared in this example, it can be confirmed that the thin film on the surface of the obtained sample is anatase TiO ₂ , and it is known from the SEM photo that it has a porous structure and no flower-shaped microspheres.

Example 7

Change the reaction time to 10h, and the remaining contents are the same as those described in Example 1. From the X-ray diffraction pattern of the sample prepared in this example, it can be confirmed that the thin film on the surface of the obtained sample is anatase TiO ₂ , and it is known from the SEM photo that it has a porous structure with flower-like microspheres.

Example 8

No ionic liquid was added, and the remaining contents were the same as described in Example 1. From the X-ray diffraction pattern of the sample prepared in this embodiment, it can be confirmed that the thin film on the surface of the obtained sample is anatase TiO ₂ , and it is known from the SEM photo that it has a porous random sheet structure.

Fig. 3 is the UV-vis DRS spectrum of the sample comparison that embodiment 1 and embodiment 8 make, as can be seen from the figure that the titanium dioxide thin film with curdled structure of embodiment 1 is compared with the sample prepared by present embodiment without adding ionic liquid The light absorption intensity in the ultraviolet region is significantly improved.

The photocatalytic performance of above-mentioned each embodiment gained sample:

Get the titanium oxide thin film obtained in above-mentioned embodiment 1-8 and place in the rhodamine B solution of 55mL 10mg/L, make the surface area of Ti sheet 43% immerse under the liquid level, remaining surface is exposed in air, then place in a rotating disk reactor.

Use an 8W ultraviolet lamp with a characteristic wavelength of 365nm as the light source to irradiate the surface of the Ti sheet, and the distance from the Ti sheet is 4.0cm; the rotation speed of the titanium sheet is 90rpm, the reaction temperature is 30°C, and the photocatalysis is carried out after half an hour of adsorption in the dark to reach the adsorption equilibrium Activity measurement, the reaction time is 3h.

After the reaction, the concentration change of rhodamine B was measured at 553nm with a UV spectrophotometer and the degradation rate was calculated accordingly. Since only less than 5% of Rhodamine B was decomposed after 3 hours of reaction without light or catalyst, the resulting error can be ignored.

Fig. 4 is a comparison of the photocatalytic activity of the titanium dioxide thin films prepared in Examples 1-8. As can be seen from Figure 4, the samples obtained in each of the examples of the present invention have good photocatalytic activity, and the activity of the thin film samples prepared after adding ionic liquids is the best in Example 1, and is higher than that of the implementation without adding ionic liquids. Example 8.

Adopt the sample gained in embodiment 1 to carry out life experiment:

The photocatalytic performance of the sample obtained in Example 1 was tested according to the above steps, except that the reaction time was 4 hours, and the concentration change of Rhodamine B was recorded every hour. After the reaction was completed, the Ti sheet was taken out and washed three times with deionized water, then dried at 100°C for 12 hours, and the above reaction was repeated 10 times in total.

The life test result is shown in Fig. 5, it can be seen that the product obtained in the present invention has stable photocatalytic activity.

The above-mentioned embodiments should be understood as only for illustrating the present invention but not for limiting the protection scope of the present invention. After reading the contents of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent changes and modifications also fall within the scope defined by the claims of the present invention.

Claims (2)

1. a preparation method of porous titanium dioxide photocatalytic film, it is characterized in that, described film and titanium sheet substrate are combined together, and the surface is porous flower-shaped microsphere structure, and its crystal form is anatase type, and concrete preparation method is : The polished titanium sheet is immersed in a mixed solution composed of hydrogen peroxide and ionic liquid 1-butyl-3-methyl-imidazolium tetrafluoroborate. The concentration of hydrogen peroxide in the mixed solution is 10~15wt%, and the ionic liquid 1- The concentration of butyl-3-methyl-imidazolium tetrafluoroborate is 0.1~0.5wt%, kept at a constant temperature of 80°C~100°C for 8~10h, washed, dried and then roasted at 450°C~500°C for 1 ~1.1 h. 2. the preparation method of porous titanium dioxide photocatalytic film as claimed in claim 1 is characterized in that, the concentration of hydrogen peroxide is 15wt% in the mixed solution, and ionic liquid 1-butyl-3-methyl-imidazole tetrafluoroborate The concentration is 0.2wt%.

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