CN103447025A - A kind of Dy/BiVO4 photocatalyst and its preparation method and application - Google Patents

Abstract

A Dy/BiVO ₄ photocatalyst and its preparation method and application, its main component is BiVO ₄ , which is a tetragonal zircon structure, and the crystal lattice of BiVO ₄ contains Dy ³⁺ . Dissolve bismuth nitrate pentahydrate and ammonium metavanadate in water respectively to obtain a bismuth salt solution and a vanadium salt solution, add the vanadium salt solution to the bismuth salt solution at a molar ratio of Bi and V of 1:1 to obtain a mixed solution, adjust the mixed solution Dy/BiVO 4 was prepared by adding dysprosium nitrate hexahydrate, the molar ratio of Dy to Bi was (2.04～13.64):100, and the Dy/BiVO ₄ was prepared by microwave hydrothermal method at 180°C for 40min with a power of 300W. The invention combines the advantages of microwave heating and hydrothermal method to synthesize powder, with fast heating speed, uniform heating, shortened reaction time and improved work efficiency. The synthesized Dy/ _BiVO4 photocatalyst has higher photocatalytic activity and can Applied to the treatment of environmental pollutants.

Description

A kind of Dy/BiVO4 photocatalyst and its preparation method and application

technical field

The invention belongs to the field of photocatalyst materials, and relates to a Dy/ _BiVO4 photocatalyst, a preparation method and application thereof.

Background technique

In recent years, the application of semiconductor photocatalytic oxidation method in wastewater treatment has attracted the attention of scholars. It uses the strong oxidizing free radicals generated by semiconductor photocatalysts under the condition of light to completely degrade organic pollutants and eventually generate Inorganic small molecules such as _H2O and _CO2 . The method has simple reaction equipment, less secondary pollution, easy operation control, low operation cost, and can effectively use sunlight as a reaction light source.

However, BiVO ₄ is an environmentally friendly semiconductor photocatalytic material, which has three crystal structures: monoclinic scheelite type, tetragonal scheelite type and tetragonal zirconite type. Among them, BiVO ₄ used to study photocatalytic performance Mainly tetragonal zircon type and monoclinic scheelite type BiVO ₄ . The monoclinic phase BiVO ₄ has a smaller band gap (2.40eV), can absorb more visible light, and the Bi-O bond in its lattice is distorted, which improves the separation efficiency of photogenerated electrons and holes, and then To a certain extent, the photocatalytic performance is improved, so among the three crystal forms of BiVO ₄ , the visible light catalytic activity of the monoclinic BiVO ₄ is the highest, which makes it one of the focuses of people's research, while the tetragonal BiVO ₄ has the highest visible light catalytic activity. There is almost no photocatalytic effect under this condition, and it has rarely been studied. However, due to the low separation efficiency of photogenerated electrons and holes, the photocatalytic effect of the pure-phase monoclinic scheelite structure _BiVO4 is not ideal. Doping can improve the photocatalytic reaction efficiency and selectivity of BiVO _4. At present, the method of doping and modifying BiVO ₄ is mostly the impregnation method, that is, in the traditional solid-phase reaction method, chemical co-precipitation method, sol-gel method, etc. After the pure phase BiVO ₄ is prepared by the hydrothermal method, etc., an appropriate metal source is selected and impregnated to dope it. This method has many processes and complicated processes.

Contents of the invention

The purpose of the present invention is to provide a Dy/ _BiVO4 photocatalyst and its preparation method and application, the method combines the advantages of microwave heating and the characteristics of hydrothermal reaction, and the synthesized Dy/ _BiVO4 photocatalyst has higher catalytic activity.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A Dy/BiVO ₄ photocatalyst, its main component is BiVO ₄ , which is a tetragonal zircon structure, and the crystal lattice of BiVO ₄ contains Dy ³⁺ , wherein the molar ratio of Dy element to Bi element is (2.04～13.64) :100.

Its shape is short columnar, and its size is nanoscale.

A preparation method of Dy/ _BiVO photocatalyst, comprises the following steps:

Step 1: dissolving Bi(NO ₃ ) ₃ ·5H ₂ O in water, and stirring evenly to obtain a bismuth salt solution; dissolving NH ₄ VO ₃ in water at 100°C, heating and stirring evenly, to obtain a vanadium salt solution;

Step 2: Add the vanadium salt solution to the bismuth salt solution according to the molar ratio of Bi and V of 1:1, and stir evenly to obtain a mixed solution;

Step 3: adjust the pH value of the mixture to 8, and stir evenly;

Step 4: Add Dy(NO ₃ ) ₃ ·6H ₂ O to the mixed solution after adjusting the pH value, and stir evenly to obtain a precursor solution, wherein the molar ratio of Dy to Bi is (2.04-13.64):100;

Step 5: Add the precursor liquid into the microwave hydrothermal reaction kettle, seal the microwave hydrothermal reaction kettle and place it in the microwave-assisted hydrothermal synthesis instrument, set the pressure at 1.1MPa, and raise the temperature from room temperature to 100°C, hold at 100°C for 8 minutes; then raise the temperature from 100°C to 150°C, hold at 150°C for 8 minutes; then raise the temperature from 150°C to 180°C, and finish the reaction after holding at 180°C for 40 minutes;

Step 6: After the reaction is finished, cool to room temperature, take out the precipitate in the microwave hydrothermal reaction kettle, wash and dry to obtain Dy/BiVO ₄ photocatalyst.

The concentration of Bi(NO ₃ ) ₃ ·5H ₂ O in the bismuth salt solution is 0.4 mol/L; the concentration of NH ₄ VO ₃ in the vanadium salt solution is 0.4 mol/L.

In step 1, dissolve Bi(NO ₃ ) ₃ ·5H ₂ O in water and stir for 20 min; dissolve NH ₄ VO ₃ in water at 100°C and heat and stir at 90-100°C for 20 min; in step 2 Stir evenly on a magnetic stirrer for 15 min.

In the step 3, the pH value of the mixed solution is adjusted with a NaOH solution having a concentration of 5 mol/L, and the dropping rate of the NaOH solution is less than or equal to 1 mL/min.

The uniform stirring in the step 3 is to stir on a magnetic stirrer for 25 minutes; the uniform stirring in the described step 4 is to stir on a magnetic stirrer for 20 minutes.

The filling ratio of the microwave hydrothermal reactor in the step 5 is 55%.

The washing in step 6 is to wash the precipitate with deionized water and absolute ethanol until neutral; the drying is to dry at a constant temperature at 75° C. for 24 hours.

Application of Dy/BiVO ₄ photocatalyst in the treatment of environmental pollutants.

Compared with the prior art, the beneficial effects of the present invention are:

The preparation method of the Dy/BiVO ₄ photocatalyst provided by the present invention uses bismuth nitrate pentahydrate (Bi(NO ₃ ) ₃ 5H ₂ O) as the bismuth source and ammonium metavanadate (NH ₄ VO ₃ ) as the vanadium source to prepare BiVO ₄ and dysprosium nitrate hexahydrate (Dy(NO ₃ ) ₃ ·6H ₂ O) as dysprosium source to prepare highly active Dy/BiVO ₄ photocatalyst powder in the nanometer scale. The present invention introduces Dy ³⁺ into the crystal lattice of BiVO ₄ and improves the efficiency of pure phase BiVO ₄ in degrading organic pollutants. In the present invention, a highly active Dy/ _BiVO4 photocatalyst is synthesized by a microwave hydrothermal method. This method combines the advantages of microwave heating and hydrothermal method, and can realize stirring at the molecular level. The heating speed is fast, the heating is uniform, and there is no temperature gradient. It has no hysteresis effect, overcomes the disadvantage of uneven heating of the hydrothermal container, shortens the reaction time, improves work efficiency, and has mild reaction conditions, simple process flow, convenient operation and short preparation cycle.

The Dy/BiVO ₄ photocatalyst provided by the present invention has a tetragonal zircon structure, its main component is BiVO ₄ , and the crystal lattice of BiVO ₄ contains Dy ³⁺ , which has high photocatalytic activity and can be applied to environmental pollutants In terms of treatment, the photocatalytic performance of pure phase BiVO ₄ has been improved, and the purpose of modifying pure phase BiVO ₄ has been achieved, which has a good application prospect.

Furthermore, the shape of the Dy/BiVO ₄ photocatalyst provided by the present invention is short columnar, and the size is nanoscale.

Description of drawings

Fig. 1 is the FE-SEM figure of the Dy/BiVO _{photocatalyst} prepared in Example 5 of the present invention;

Figure 2 is the XRD spectrum of the Dy/ _BiVO4 photocatalyst prepared under different Dy ³⁺ additions in the present invention, where a is the XRD spectrum of the pure phase BiVO ₄ without adding Dy, and b~g are respectively The Dy/ _BiVO4 photocatalyst XRD spectrum that example 6 prepares;

Fig. 3 is the degradation rate-time curve of the degradation Rhodamine B of the Dy/ _BiVO photocatalyst prepared under different Dy ³⁺ additions of the present invention-time curve, wherein RhB is the degradation curve of Rhodamine B self when not adding catalyst; The degradation curve of the pure phase BiVO ₄ with Dy added, b~g are the degradation curves of the Dy/BiVO ₄ photocatalysts prepared in Examples 1 to 6, respectively.

Detailed ways

The present invention will be described in further detail below in conjunction with specific embodiments and accompanying drawings.

Example 1:

A Dy/BiVO ₄ photocatalyst whose main component is BiVO ₄ with a tetragonal zircon structure, and the crystal lattice of BiVO ₄ contains Dy ³⁺ , wherein the molar ratio of Dy element to Bi element is 2.04:100.

A preparation method of Dy/ _BiVO photocatalyst, comprises the following steps:

Step 1: Dissolve Bi(NO ₃ ) ₃ ·5H ₂ O in deionized water, and stir on a magnetic stirrer for 20 minutes to obtain a bismuth salt solution with a Bi(NO ₃ ) ₃ ·5H ₂ O concentration of 0.4 mol/L; Dissolve NH ₄ VO ₃ in deionized water at 100°C, heat and stir at 100°C for 20 minutes to obtain a vanadium salt solution with an NH ₄ VO ₃ concentration of 0.4mol/L;

Step 2: slowly drop the vanadium salt solution into the bismuth salt solution according to the molar ratio of Bi and V of 1:1, and stir on a magnetic stirrer for 15 minutes to obtain a mixed solution;

Step 3: Add dropwise NaOH solution with a concentration of 5 mol/L to the mixture at a rate of 1 mL/min, adjust the pH of the mixture to 8, and stir on a magnetic stirrer for 25 minutes;

Step 4: Add Dy(NO ₃ ) ₃ 6H ₂ O to the mixed solution after adjusting the pH value, stir on a magnetic stirrer for 20 minutes, and prepare a precursor solution, wherein the molar ratio of Dy to Bi is 2.04:100 ;

Step 5: Add the precursor liquid into the microwave hydrothermal reactor, control the filling ratio of the microwave hydrothermal reactor to 55%, then seal the microwave hydrothermal reactor and place it in the microwave hydrothermal synthesizer, select the microwave temperature control mode , set the pressure at 1.1MPa, under the microwave power of 300W, raise the temperature from room temperature to 100°C, keep it at 100°C for 8 minutes; then raise the temperature from 100°C to 150°C, keep it at 150°C for 8 minutes; ℃, finish the reaction after incubating at 180℃ for 40min;

Step 6: After the reaction is finished, cool to room temperature, take out the precipitate in the microwave hydrothermal reaction kettle, wash the precipitate with deionized water and absolute ethanol until it is neutral, and then dry it at a constant temperature at 75°C for 24 hours to obtain Dy/ _BiVO4 photocatalyst.

Example 2:

A Dy/BiVO ₄ photocatalyst whose main component is BiVO ₄ with a tetragonal zircon structure, and the crystal lattice of BiVO ₄ contains Dy ³⁺ , wherein the molar ratio of Dy element to Bi element is 4.17:100.

A preparation method of Dy/ _BiVO photocatalyst, comprises the following steps:

Step 1: Dissolve Bi(NO ₃ ) ₃ ·5H ₂ O in deionized water, and stir on a magnetic stirrer for 20 minutes to obtain a bismuth salt solution with a Bi(NO ₃ ) ₃ ·5H ₂ O concentration of 0.4 mol/L; Dissolve NH ₄ VO ₃ in deionized water at 100°C, heat and stir at 90°C for 20 minutes to obtain a vanadium salt solution with an NH ₄ VO ₃ concentration of 0.4mol/L;

Step 2: slowly drop the vanadium salt solution into the bismuth salt solution according to the molar ratio of Bi and V of 1:1, and stir on a magnetic stirrer for 15 minutes to obtain a mixed solution;

Step 3: Add dropwise NaOH solution with a concentration of 5 mol/L to the mixture at a rate of 0.5 mL/min, adjust the pH of the mixture to 8, and stir on a magnetic stirrer for 25 minutes;

Step 4: Add Dy(NO ₃ ) ₃ ·6H ₂ O to the mixed solution after adjusting the pH value, stir on a magnetic stirrer for 20 minutes, and prepare a precursor solution, wherein the molar ratio of Dy to Bi is 4.17:100 ;

Step 5: Add the precursor liquid into the microwave hydrothermal reactor, control the filling ratio of the microwave hydrothermal reactor to 55%, then seal the microwave hydrothermal reactor and place it in the microwave hydrothermal synthesizer, select the microwave temperature control mode , set the pressure at 1.1MPa, under the microwave power of 300W, raise the temperature from room temperature to 100°C, keep it at 100°C for 8 minutes; then raise the temperature from 100°C to 150°C, keep it at 150°C for 8 minutes; ℃, finish the reaction after incubating at 180℃ for 40min;

Step 6: After the reaction is finished, cool to room temperature, take out the precipitate in the microwave hydrothermal reaction kettle, wash the precipitate with deionized water and absolute ethanol until it is neutral, and then dry it at a constant temperature at 75°C for 24 hours to obtain Dy/ _BiVO4 photocatalyst.

Example 3:

A Dy/BiVO ₄ photocatalyst, its main component is BiVO ₄ , which is a tetragonal zircon structure, and the crystal lattice of BiVO ₄ contains Dy ³⁺ , wherein the molar ratio of Dy element to Bi element is 6.38:100.

A preparation method of Dy/ _BiVO photocatalyst, comprises the following steps:

Step 1: Dissolve Bi(NO ₃ ) ₃ ·5H ₂ O in deionized water, and stir on a magnetic stirrer for 20 minutes to obtain a bismuth salt solution with a Bi(NO ₃ ) ₃ ·5H ₂ O concentration of 0.4 mol/L; Dissolve NH ₄ VO ₃ in deionized water at 100°C, heat and stir at 95°C for 20 minutes to obtain a vanadium salt solution with an NH ₄ VO ₃ concentration of 0.4mol/L;

Step 2: slowly drop the vanadium salt solution into the bismuth salt solution according to the molar ratio of Bi and V of 1:1, and stir on a magnetic stirrer for 15 minutes to obtain a mixed solution;

Step 3: Add dropwise NaOH solution with a concentration of 5 mol/L to the mixed solution at a rate of 0.8 mL/min, adjust the pH of the mixed solution to 8, and stir on a magnetic stirrer for 25 minutes;

Step 4: Add Dy(NO ₃ ) ₃ 6H ₂ O to the mixed solution after adjusting the pH value, stir on a magnetic stirrer for 20 minutes, and prepare a precursor solution, wherein the molar ratio of Dy to Bi is 6.38:100 ;

Step 5: Add the precursor liquid into the microwave hydrothermal reactor, control the filling ratio of the microwave hydrothermal reactor to 55%, then seal the microwave hydrothermal reactor and place it in the microwave hydrothermal synthesizer, select the microwave temperature control mode , set the pressure at 1.1MPa, under the microwave power of 300W, raise the temperature from room temperature to 100°C, keep it at 100°C for 8 minutes; then raise the temperature from 100°C to 150°C, keep it at 150°C for 8 minutes; ℃, finish the reaction after incubating at 180℃ for 40min;

Step 6: After the reaction is finished, cool to room temperature, take out the precipitate in the microwave hydrothermal reaction kettle, wash the precipitate with deionized water and absolute ethanol until it is neutral, and then dry it at a constant temperature at 75°C for 24 hours to obtain Dy/ _BiVO4 photocatalyst.

Example 4:

A Dy/BiVO ₄ photocatalyst, the main component of which is BiVO ₄ , which is a tetragonal zircon structure, and the crystal lattice of BiVO ₄ contains Dy ³⁺ , wherein the molar ratio of Dy element to Bi element is 8.70:100.

A preparation method of Dy/ _BiVO photocatalyst, comprises the following steps:

Step 1: Dissolve Bi(NO ₃ ) ₃ ·5H ₂ O in deionized water, and stir on a magnetic stirrer for 20 minutes to obtain a bismuth salt solution with a Bi(NO ₃ ) ₃ ·5H ₂ O concentration of 0.4 mol/L; Dissolve NH ₄ VO ₃ in deionized water at 100°C, heat and stir at 100°C for 20 minutes to obtain a vanadium salt solution with an NH ₄ VO ₃ concentration of 0.4mol/L;

Step 2: slowly drop the vanadium salt solution into the bismuth salt solution according to the molar ratio of Bi and V of 1:1, and stir on a magnetic stirrer for 15 minutes to obtain a mixed solution;

Step 3: Add dropwise NaOH solution with a concentration of 5 mol/L to the mixture at a rate of 1 mL/min, adjust the pH of the mixture to 8, and stir on a magnetic stirrer for 25 minutes;

Step 4: Add Dy(NO ₃ ) ₃ ·6H ₂ O to the mixed solution after adjusting the pH value, stir on a magnetic stirrer for 20 minutes, and prepare a precursor solution, wherein the molar ratio of Dy to Bi is 8.70:100 ;

Step 5: Add the precursor liquid into the microwave hydrothermal reactor, control the filling ratio of the microwave hydrothermal reactor to 55%, then seal the microwave hydrothermal reactor and place it in the microwave hydrothermal synthesizer, select the microwave temperature control mode , set the pressure at 1.1MPa, under the microwave power of 300W, raise the temperature from room temperature to 100°C, keep it at 100°C for 8 minutes; then raise the temperature from 100°C to 150°C, keep it at 150°C for 8 minutes; ℃, finish the reaction after incubating at 180℃ for 40min;

Step 6: After the reaction is finished, cool to room temperature, take out the precipitate in the microwave hydrothermal reaction kettle, wash the precipitate with deionized water and absolute ethanol until it is neutral, and then dry it at a constant temperature at 75°C for 24 hours to obtain Dy/ _BiVO4 photocatalyst.

Example 5:

A Dy/BiVO ₄ photocatalyst whose main component is BiVO ₄ with a tetragonal zircon structure, and the crystal lattice of BiVO ₄ contains Dy ³⁺ , wherein the molar ratio of Dy element to Bi element is 11.11:100.

A preparation method of Dy/ _BiVO photocatalyst, comprises the following steps:

Step 1: Dissolve Bi(NO ₃ ) ₃ ·5H ₂ O in deionized water, and stir on a magnetic stirrer for 20 minutes to obtain a bismuth salt solution with a Bi(NO ₃ ) ₃ ·5H ₂ O concentration of 0.4 mol/L; Dissolve NH ₄ VO ₃ in deionized water at 100°C, heat and stir at 98°C for 20 minutes to obtain a vanadium salt solution with an NH ₄ VO ₃ concentration of 0.4mol/L;

Step 2: slowly drop the vanadium salt solution into the bismuth salt solution according to the molar ratio of Bi and V of 1:1, and stir on a magnetic stirrer for 15 minutes to obtain a mixed solution;

Step 3: Add dropwise NaOH solution with a concentration of 5 mol/L to the mixture at a rate of 0.3 mL/min, adjust the pH of the mixture to 8, and stir on a magnetic stirrer for 25 minutes;

Step 4: Add Dy(NO ₃ ) ₃ 6H ₂ O to the mixed solution after adjusting the pH value, stir on a magnetic stirrer for 20 minutes, and prepare a precursor solution, wherein the molar ratio of Dy to Bi is 11.11:100 ;

Step 5: Add the precursor liquid into the microwave hydrothermal reactor, control the filling ratio of the microwave hydrothermal reactor to 55%, then seal the microwave hydrothermal reactor and place it in the microwave hydrothermal synthesizer, select the microwave temperature control mode , set the pressure at 1.1MPa, under the microwave power of 300W, raise the temperature from room temperature to 100°C, keep it at 100°C for 8 minutes; then raise the temperature from 100°C to 150°C, keep it at 150°C for 8 minutes; ℃, finish the reaction after incubating at 180℃ for 40min;

Step 6: After the reaction is finished, cool to room temperature, take out the precipitate in the microwave hydrothermal reaction kettle, wash the precipitate with deionized water and absolute ethanol until it is neutral, and then dry it at a constant temperature at 75°C for 24 hours to obtain Dy/ _BiVO4 photocatalyst.

Figure 1 is the FE-SEM image of the Dy/ _BiVO4 photocatalyst prepared in Example 5. It can be seen from the figure that its crystal morphology is short columnar, and the size in the short diameter direction is about 50nm. It can be seen that the size of the prepared powder is reached the nanoscale.

Embodiment 6:

A Dy/BiVO ₄ photocatalyst whose main component is BiVO ₄ with a tetragonal zircon structure, and the crystal lattice of BiVO ₄ contains Dy ³⁺ , wherein the molar ratio of Dy element to Bi element is 13.64:100.

A preparation method of Dy/ _BiVO photocatalyst, comprises the following steps:

Step 1: Dissolve Bi(NO ₃ ) ₃ ·5H ₂ O in deionized water, and stir on a magnetic stirrer for 20 minutes to obtain a bismuth salt solution with a Bi(NO ₃ ) ₃ ·5H ₂ O concentration of 0.4 mol/L; Dissolve NH ₄ VO ₃ in deionized water at 100°C, heat and stir at 96°C for 20 minutes to obtain a vanadium salt solution with an NH ₄ VO ₃ concentration of 0.4mol/L;

Step 2: slowly drop the vanadium salt solution into the bismuth salt solution according to the molar ratio of Bi and V of 1:1, and stir on a magnetic stirrer for 15 minutes to obtain a mixed solution;

Step 3: Add dropwise NaOH solution with a concentration of 5 mol/L to the mixture at a rate of 0.4 mL/min, adjust the pH of the mixture to 8, and stir on a magnetic stirrer for 25 minutes;

Step 4: Add Dy(NO ₃ ) ₃ ·6H ₂ O to the mixed solution after adjusting the pH value, stir on a magnetic stirrer for 20 minutes, and prepare a precursor solution, wherein the molar ratio of Dy to Bi is 13.64:100 ;

Step 5: Add the precursor liquid into the microwave hydrothermal reactor, control the filling ratio of the microwave hydrothermal reactor to 55%, then seal the microwave hydrothermal reactor and place it in the microwave hydrothermal synthesizer, select the microwave temperature control mode , set the pressure at 1.1MPa, under the microwave power of 300W, raise the temperature from room temperature to 100°C, keep it at 100°C for 8 minutes; then raise the temperature from 100°C to 150°C, keep it at 150°C for 8 minutes; ℃, finish the reaction after incubating at 180℃ for 40min;

Step 6: After the reaction is finished, cool to room temperature, take out the precipitate in the microwave hydrothermal reaction kettle, wash the precipitate with deionized water and absolute ethanol until it is neutral, and then dry it at a constant temperature at 75°C for 24 hours to obtain Dy/ _BiVO4 photocatalyst.

Fig. 2 is _the XRD spectrum of the Dy/ _BiVO photocatalyst prepared under different Dy ³⁺ additions, wherein a is the XRD spectrum of the pure phase _BiVO without adding Dy, and the pure phase BiVO without adding Dy is according to the present invention The preparation method is obtained without adding Dy(NO ₃ ) ₃ ·6H ₂ O in step 4; b-g are the XRD spectra of the Dy/BiVO ₄ photocatalysts prepared in Examples 1-6, respectively. The intensity on the ordinate in Figure 2 is the relative intensity, and the 2-Theta on the abscissa is the diffraction angle. It can be seen from the figure that all the diffraction peaks of the pure phase BiVO ₄ without Dy added are consistent with the PDF card (JCPDS NO.75-1866), indicating that its crystal phase is monoclinic scheelite phase, and the Dy/BiVO after adding Dy ₄ All the diffraction peaks of the photocatalyst are consistent with the PDF card (JCPDSNO.14-0133), indicating that its crystal phase is all tetragonal zircon phase.

Figure 3 is the degradation rate-time curve of the degradation of Rhodamine B by Dy/ _BiVO photocatalysts prepared under different Dy ³⁺ additions, where RhB is the degradation curve of Rhodamine B itself when no catalyst is added; a is the degradation curve without adding Dy The degradation curve of the pure phase BiVO ₄ without adding Dy is obtained according to the preparation method of the present invention without adding Dy(NO ₃ ) ₃ ·6H ₂ O in step 4 _; Degradation curves of the Dy/BiVO ₄ photocatalysts prepared in Examples 1 to 6. The C/C ₀ on the ordinate in Figure 3 is the ratio of the degraded concentration of rhodamine B to its initial concentration at a certain moment. It can be seen from the figure that, except that the degradation effect of the Dy/BiVO ₄ photocatalyst prepared in Example 3 is lower than that of the pure phase BiVO ₄ , the degradation effect of the Dy/BiVO ₄ photocatalyst prepared in other examples is lower than that of the pure phase BiVO 4 . The degradation effect of BiVO ₄ is good, and the degradation rate of Rhodamine B by the Dy/BiVO ₄ photocatalyst prepared in Example 5 reaches 94.40% under 120min of light irradiation, while the pure phase BiVO ₄ can degrade Rhodamine B after 120min of light irradiation The degradation rate of B is only 37.26%. It can be seen that the degradation rate of the Dy/BiVO ₄ photocatalyst prepared in Example 5 is 57.14% higher than that of the pure monoclinic BiVO ₄ after 120 min of light irradiation. Therefore, the tetragonal phase Er/BiVO ₄ visible light photocatalyst prepared by the present invention can be used to degrade organic matter, and can be applied to the treatment of environmental pollutants.

The above is only one embodiment of the present invention, not all or the only embodiment. Any equivalent transformation of the technical solution of the present invention adopted by those of ordinary skill in the art by reading the description of the present invention is the right of the present invention. covered by the requirements.

Claims (10)

1. a Dy/BiVO ₄photochemical catalyst is characterized in that: its main component is BiVO ₄, be cubic Zircon cut structure, and BiVO ₄lattice in contain Dy ³⁺, wherein the mol ratio of Dy element and Bi element is (2.04～13.64): 100.

2. Dy/BiVO according to claim 1 ₄photochemical catalyst is characterized in that: its pattern is short cylinder, is of a size of nanoscale.

3. a Dy/BiVO ₄the preparation method of photochemical catalyst, is characterized in that, comprises the following steps:

Step 1: by Bi (NO ₃) ₃5H ₂o is soluble in water, stirs, and obtains the bismuth salting liquid; By NH ₄vO ₃be dissolved in the water of 100 ℃, heating stirs, and obtains vanadic salts solution;

Step 2: the mol ratio by Bi and V is that 1:1 is added to vanadic salts solution in the bismuth salting liquid, stirs, and obtains mixed liquor;

Step 3: the pH value of regulating mixed liquor is 8, stirs;

Step 4: by Dy (NO ₃) ₃6H ₂o joins in the mixed liquor of having regulated after the pH value, stirs, and obtains precursor liquid, and wherein the mol ratio of Dy and Bi is (2.04～13.64): 100;

Step 5: precursor liquid is added in microwave hydrothermal reaction kettle, the microwave hydrothermal reaction kettle sealing is placed in microwave assisted hydrothermal synthesis apparatus, setting pressure is 1.1MPa, under the microwave power of 300W, from room temperature, is warming up to 100 ℃, at 100 ℃ of insulation 8min; Then be warming up to 150 ℃ from 100 ℃, at 150 ℃ of insulation 8min; Be warming up to 180 ℃, end reaction after 180 ℃ of insulation 40min from 150 ℃ again;

Step 6: question response is cooled to room temperature after finishing, and takes out the sediment in microwave hydrothermal reaction kettle, washing, and drying, obtain Dy/BiVO ₄photochemical catalyst.

4. Dy/BiVO according to claim 3 ₄the preparation method of photochemical catalyst is characterized in that: Bi (NO in described bismuth salting liquid ₃) ₃5H ₂the concentration of O is 0.4mol/L; NH in vanadic salts solution ₄vO ₃concentration be 0.4mol/L.

5. according to the described Dy/BiVO of claim 3 or 4 ₄the preparation method of photochemical catalyst is characterized in that: in described step 1 by Bi (NO ₃) ₃5H ₂o stirring soluble in water 20min; By NH ₄vO ₃be dissolved in the water of 100 ℃ and add thermal agitation 20min under 90-100 ℃; Stirring in described step 2 is to stir 15min on magnetic stirring apparatus.

6. Dy/BiVO according to claim 3 ₄the preparation method of photochemical catalyst is characterized in that: the NaOH solution that is 5mol/L by concentration in described step 3 is regulated the pH value of mixed liquor, and the rate of addition of NaOH solution is less than or equal to 1mL/min.

7. according to the described Dy/BiVO of claim 3 or 6 ₄the preparation method of photochemical catalyst is characterized in that: stirring in described step 3 is to stir 25min on magnetic stirring apparatus; Stirring in described step 4 is to stir 20min on magnetic stirring apparatus.

8. Dy/BiVO according to claim 3 ₄the preparation method of photochemical catalyst is characterized in that: in described step 5, the packing ratio of microwave hydrothermal reaction kettle is 55%.

9. Dy/BiVO according to claim 3 ₄the preparation method of photochemical catalyst is characterized in that: the washing in described step 6 is extremely neutral by deionized water and absolute ethanol washing sediment; Described drying is at 75 ℃ of lower freeze-day with constant temperature 24h.

10. Dy/BiVO according to claim 1 ₄the application of photochemical catalyst aspect the environmental contaminants processing.

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