Nanometer long-rod-shaped Bi2Ti4O11 / BiOCl composite photocatalyst and preparation method thereof

Abstract

The invention discloses a nanometer long rod-shaped Bi2Ti4O11 / BiOCl composite photocatalyst and a preparation method of the nanometer long rod-shaped Bi2Ti4O11 / BiOCl composite photocatalyst. The preparation method specifically comprises the following steps: mixing raw materials such as B2O3, Bi2O3, R2O, TiO2 and the like according to a certain proportion, melting at a high temperature to prepare glass, crushing the glass into glass powder, and preparing the glass ceramic powder containing Bi2Ti4O11 long rod-shaped crystals by using a glass crystallization process. The preparation method comprises the following steps: preparing a Bi2Ti4O11 crystal, stirring and soaking glass ceramic powder in diluted hydrochloric acid for a period of time, carrying out acid pickling to remove a glass phase, and reacting the Bi2Ti4O11 crystal with hydrochloric acid to generate a BiOCl crystal on the surface of the Bi2Ti4O11 crystal, thereby obtaining the pure nano long rod-shaped Bi2Ti4O11 / BiOCl composite catalyst. The preparation method disclosed by the invention has the beneficial effects that the prepared nano long-rod-shaped Bi2Ti4O11 / BiOCl composite catalyst is relatively low in cost and high in photocatalytic degradation efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of preparation of photocatalysts, and particularly relates to a nano long rod-shaped Bi2Ti4O 11 / BiOCl composite photocatalyst and a preparation method thereof. BACKGROUND

[0002] Bi2Ti4O 11 has a monoclinic crystal structure and has antiferromagnetic properties, and has two crystal phases: alpha phase at room temperature, which exhibits antiferromagnetic properties; and beta phase when heated to 240 DEG C, which exhibits ferromagnetic properties. This material is mainly used in the fields of microwave communication and temperature sensing. In addition, Bi2Ti4O 11 also has excellent photocatalytic properties, but there are few studies on its photocatalytic properties at present.

[0003] This phenomenon is mainly due to the limitations of existing preparation methods: Bi2Ti4O 11 crystals prepared by a solid-phase sintering method have a large crystal size, and although they are often used to prepare Bi2Ti4O 11 ceramics in the field of microwave communication, their photocatalytic properties are poor; and the solution method is complex, for example, the rare earth-doped Bi2Ti4O 11 high-purity green nanofiber preparation method disclosed in Chinese Patent CN112176456A uses tetrabutyl titanate and bismuth nitrate as raw materials to prepare one-dimensional nanomaterials by an electrospinning method, which can be used in the field of temperature sensing (utilizing the performance of the intensity of luminescence changing with temperature under infrared light excitation), but has the problems of high cost and low single yield, and the prepared crystal material has weak visible light absorption ability and is difficult to be applied to the scene of photocatalytic degradation of wastewater treatment.

[0004] Therefore, in order to solve the above problems, the application provides a nano long rod-shaped Bi2Ti4O 11 / BiOCl composite photocatalyst and a preparation method thereof. SUMMARY

[0005] The application aims to overcome the defects of the prior art and provides a nano long rod-shaped Bi2Ti4O 11 / BiOCl composite photocatalyst and a preparation method thereof.

[0006] The object of the application can be achieved by the following technical solutions: A preparation method of a nano long rod-shaped Bi2Ti4O 11 / BiOCl composite photocatalyst, comprising the following steps: Step 1: After mixing the glass raw materials, melting, then directly pouring into water for water quenching to obtain glass slag, drying, crushing and grinding into base glass powder; Step 2: Put the base glass powder on a stainless steel plate and directly send it into a high-temperature furnace for crystallization heat treatment to obtain a glass-ceramic powder; Step 3: Put the glass-ceramic powder into dilute hydrochloric acid, stir and etch at room temperature, centrifuge, then add excess deionized water for cleaning twice, and dry to obtain a composite photocatalyst.

[0007] More preferably, the glass raw material comprises the following components: 22-30% Bi2O3, 22-30% TiO2, 37-50% B2O3, and 3-6% R2O by mass percentage; wherein the R2O comprises one or more of Li2O, K2O, and Na2O.

[0008] More preferably, the composite photocatalyst is a long rod shape, including a round rod or a square rod, with a diameter of 50-200 nm and a length of 0.2-2 µm.

[0009] More preferably, the melting process parameters are: temperature 1000-1100 ℃, and time 1-2 h.

[0010] More preferably, the particle size of the base glass powder is less than 1 mm.

[0011] More preferably, the crystallization heat treatment process parameters are: temperature 750-900 ℃, and time 60-150 min.

[0012] More preferably, the concentration of the dilute hydrochloric acid is 5-10 wt%; and the etching time is 10-60 min.

[0013] Compared with the prior art, the present application has the following advantages: The present application uses a glass crystallization method to first prepare Bi2Ti4O 11 crystals in the glass, and then uses an acid etching method to clean the glass phase and generate BiOCl crystal phase on the surface of the crystals by using dilute hydrochloric acid, thereby obtaining a Bi2Ti4O 11 / BiOCl composite photocatalyst. The specific process is as follows: Firstly, the present application uses inorganic reagents commonly used in the glass industry as raw materials, which greatly reduces the production cost; at the same time, the preparation process is simple and efficient, and no organic waste liquid is generated throughout the process, which meets the green chemistry concept; in addition, the product yield of this method is also significantly higher than that of other preparation processes.

[0014] Secondly, the present application uses a glass crystallization method, which can precisely control the growth of Bi2Ti4O 11 crystals, so that they form a long rod structure, thereby greatly increasing the specific surface area and providing more photocatalytic active sites; at the same time, this method can also control the size of the Bi2Ti4O 11The crystal surface generates BiOCl crystal phase, forms a composite structure, and further significantly improves the photocatalytic performance of the material. BRIEF DESCRIPTION OF DRAWINGS

[0015] The application will be further described below with reference to the drawings.

[0016] Figure 1 XRD pattern of the glass slag obtained by water quenching of the glass water of the embodiment step S1; Figure 2 XRD comparison pattern of the glass-ceramic powder obtained in step S3 of the embodiment and the composite catalyst after acid washing obtained in step S4; Figure 3 SEM pattern of the composite catalyst after acid washing obtained in step S4 of the embodiment; Figure 4 TEM pattern of the composite catalyst after acid washing obtained in step S4 of the embodiment; Figure 5 SEM pattern of the composite catalyst after acid washing obtained in step S4 of the embodiment; Figure 6 Organic matter degradation and absorption graph of the composite photocatalytic material after acid washing obtained in step S4 of the embodiment on organic wastewater; Figure 7 Cycle degradation efficiency curve of the composite photocatalytic material after acid washing obtained in step S4 of the embodiment. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, not all. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0018] Embodiment one: a nano-long rod-shaped Bi2Ti4O 11 The preparation method of the nano-long rod-shaped Bi2Ti4O S1, the raw materials of the glass powder are weighed according to the mass percentage (B2O3 37%, Bi2O3 30%, Na2O 3%, TiO2 30% by mass percentage), melted at 1000℃ for 1h, then directly poured into water for water quenching, and the glass slag is obtained; S2, the glass slag obtained in step S1 is dried, crushed and ground into glass powder with a particle size of less than 1mm; S3, the glass powder obtained in step S2 is placed on a stainless steel plate and directly sent into a high-temperature furnace for crystallization heat treatment, the crystallization temperature is 850 DEG C, and the time is 90 min, to obtain a glass-ceramic powder; S4, the glass-ceramic powder obtained in step S3 is placed in 10% dilute hydrochloric acid at room temperature, stirred and cleaned for 60 min, centrifuged, then excess deionized water is added to clean twice, and after drying, the nano long rod-shaped Bi2Ti4O 11 / BiOCl composite photocatalyst is obtained.

[0019] Example Two: A preparation method of a nano long rod-shaped Bi2Ti4O 11 / BiOCl composite photocatalyst, comprising the following steps: S1, the raw materials of the glass powder are weighed according to the mass percentage (B2O3 50%, Bi2O3 22%, Na2O 6%, TiO2 22% according to the mass percentage), mixed uniformly, melted at 1100 DEG C for 2 h, then directly poured into water for water quenching, and glass slag is obtained; S2, the glass slag obtained in step S1 is dried, crushed and ground into a glass powder with a particle size of less than 1 mm; S3, the glass powder obtained in step S2 is placed on a stainless steel plate and directly sent into a high-temperature furnace for crystallization heat treatment, the crystallization temperature is 750 DEG C, and the time is 60 min, to obtain a glass-ceramic powder; S4, the glass-ceramic powder obtained in step S3 is placed in 5% dilute hydrochloric acid at room temperature, stirred and cleaned for 15 min, centrifuged, then excess deionized water is added to clean twice, and after drying, the nano long rod-shaped Bi2Ti4O 11 / BiOCl composite photocatalyst is obtained.

[0020] Test experiment (one): (1) The glass slag obtained by water quenching of the glass in step S1 of Example One, the glass-ceramic powder obtained in step S3, and the acid-washed composite catalyst obtained in step S4 are respectively subjected to XRD test, and the results are shown in Figure 1 and Figure 2 ; (2) The surface morphology of the acid-washed composite catalyst obtained in step S4 in the preparation process of Example One and Example Two is observed by SEM, and the results are shown in Figure 3 and Figure 5 ; (3) The acid-washed composite catalyst obtained in step S4 of Example One is subjected to TEM analysis, and the results are shown in Figure 4 .

[0021] Test experiment (two): (1) Configuration initialization COD (Chemical Oxygen Demand) of 10 mg / L simulated organic wastewater solution; the composite photocatalyst obtained in step S4 of Example One is weighed and added to the organic wastewater solution, and stirred for 30 min under light shielding conditions to make the catalyst fully contact with the pollutants and reach adsorption equilibrium, after which the light source is turned on to start the photocatalytic reaction, and the reaction lasts for 20 min, during which COD is measured at regular time intervals to calculate the degradation rate, and the results are shown in Table 1. Figure 6 (2) After the first reaction, the composite photocatalytic material particles are separated by centrifugation, washed with deionized water for 2 times, dried, and the above test steps are repeated for three cycles, and the results are shown in Table 2. Figure 7

[0022] Conclusion: The Bi2Ti4O 11 / BiOCl composite photocatalytic material with uniform morphology and controllable size is successfully prepared by combining the glass powder crystallization method with the acid etching process. By adjusting the glass raw material composition, crystallization heat treatment system and acid washing conditions in different examples, it is verified that the method has good repeatability and adjustability.

[0023] Figure 1 The XRD pattern of the glass slag obtained in step S1 of Example One is shown in Figure 1, and the results show that the prepared glass has good glass forming property.

[0024] Figure 2 The XRD comparison chart of the microcrystalline glass powder obtained in step S3 and the composite catalyst after acid washing obtained in step S4 of Example One is shown in Figure 2, and the microcrystalline glass after crystallization contains Bi2Ti4O 11 crystals, and new BiOCl diffraction peaks appear after acid washing, indicating that new BiOCl crystal phase is generated during the acid washing process.

[0025] Figure 3 The SEM pattern of the composite catalyst after acid washing obtained in step S4 of Example One is shown in Figure 3, and the prepared Bi2Ti4O 11 / BiOCl composite photocatalyst is in the shape of a rectangular rod with uniform size.

[0026] Figure 4 The TEM pattern of the composite catalyst after acid washing obtained in step S4 is shown in Figure 4, and it can be observed that BiOCl crystals are generated on the surface of Bi2Ti4O 11 crystals, confirming the successful construction of the composite material.

[0027] Figure 5 The SEM pattern of the composite catalyst after acid washing obtained in step S4 of Example Two is shown in Figure 5, and the prepared Bi2Ti4O 11 ​​The / BiOCl composite photocatalyst is in the shape of a round rod, indicating that the morphology characteristics of the catalyst can be regulated by adjusting the raw material ratio and process parameters.

[0028] Figure 6 The organic matter degradation absorption graph of the acid-washed composite photocatalytic material obtained in step S4 in Example 1 is shown in the following table.

[0029] Figure 7 The cyclic degradation efficiency curve of the acid-washed composite photocatalytic material obtained in step S4 in Example 1 is shown in the following table; the results show that the composite photocatalytic material has good stability and reusability.

[0030] In summary: the present application provides a low-cost, environmentally friendly, efficient nano long rod-shaped Bi2Ti4O 11 The preparation method of the / BiOCl composite photocatalytic material. The method uses common raw materials in the glass industry, and the preparation process is simple and stable, does not need to use organic solvents, and has high yield, and is suitable for industrial production. At the same time, by adjusting the glass composition, crystallization temperature and acid washing conditions and other parameters, the morphology and composition of the catalyst can be accurately controlled to meet the needs of different application scenarios, and has broad application prospects in the fields of environmental governance such as wastewater treatment and air purification.

[0031] In the description of the specification, the description of the reference terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0032] The above is only an example and description of the present application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or use similar ways to replace, as long as they do not deviate from the invention or exceed the scope defined by the present claims, which shall be within the protection scope of the present application.

Claims

1. A nanorod-shaped Bi2Ti4O 11 A method for preparing a composite photocatalyst of BiOCl, characterized in that: The following steps are involved: Step 1: Mix the glass raw materials, melt them, quench them with water to obtain glass slag, dry them, grind them to obtain basic glass powder; Step 2: Sending the base glass powder into a high-temperature furnace for crystallization heat treatment to obtain micro-ceramic glass powder; Step 3: At room temperature, use dilute hydrochloric acid to etch the microcrystalline glass powder, wash and dry it to obtain a composite photocatalyst.

2. A nanorod-shaped Bi2Ti4O according to claim 1 11 A method for preparing a composite photocatalyst of BiOCl, characterized in that: The glass raw material includes the following components: by mass percentage, 22-30% Bi2O3, 22-30% TiO2, 37-50% B2O3, and 3-6% R2O; wherein the R2O includes one or more of Li2O, K2O, and Na2O.

3. The nanorod-shaped Bi2Ti4O according to claim 1 11 A method for preparing a composite photocatalyst of BiOCl, characterized in that: The composite photocatalyst is in the shape of a long rod, including a round rod or a square rod, with a diameter of 50-200 nm and a length of 0.2-2 μm.

4. The nanorod-shaped Bi2Ti4O according to claim 1 11 A method for preparing a composite photocatalyst of BiOCl, characterized in that: The melting process parameters are: temperature 1000-1100° C., time 1-2 h.

5. The nanorod-shaped Bi2Ti4O according to claim 1 11 A method for preparing a composite photocatalyst of BiOCl, characterized in that: The particle size of the basic glass powder is less than 1 mm.

6. The nanorod-shaped Bi2Ti4O according to claim 1 11 A method for preparing a composite photocatalyst of BiOCl, characterized in that: The process parameters of the crystallization heat treatment are: temperature 750-900° C., time 60-150 min.

7. The nanorod-shaped Bi2Ti4O according to claim 1 11 A method for preparing a composite photocatalyst of BiOCl, characterized in that: The concentration of the dilute hydrochloric acid is 5-10 wt %; and the acid etching time is 10-60 min.

8. The nanorod-shaped Bi2Ti4O according to any one of claims 1 to 7 11 A composite photocatalyst is obtained by the preparation method of / BiOCl composite photocatalyst.

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