CN111729671A - A kind of zinc ferrite/bismuth vanadate nano-heterostructure composite material and preparation method and application thereof - Google Patents

Abstract

The invention provides a zinc ferrite/bismuth vanadate nano-heterostructure composite material, a preparation method and application thereof, and relates to the technical field of nano-semiconductor composite materials. The zinc ferrite/bismuth vanadate nano-heterostructure composite material provided by the present invention comprises BiVO ₄ having a decahedral structure and ZnFe ₂ O ₄ nanoparticles supported on the surface of the BiVO ₄ . In the present invention, BiVO ₄ and ZnFe ₂ O ₄ are compounded to form a heterostructure, which promotes the separation of photo-generated electrons and holes, reduces the probability of photo-generated electrons and holes recombination, improves the photocatalytic performance of the composite material, and broadens the Compared with pure phase BiVO ₄ , it has stronger visible light response, lower photogenerated carrier recombination rate, better visible light catalytic degradation performance and good cycle performance, and has good application prospects.

Description

A kind of zinc ferrite/bismuth vanadate nano-heterostructure composite material and preparation method thereof application

technical field

The invention relates to the technical field of nano-semiconductor composite materials, in particular to a zinc ferrite/bismuth vanadate nano-heterostructure composite material and a preparation method and application thereof.

Background technique

Semiconductor photocatalytic degradation technology is an emerging pollution treatment technology, which has the advantages of environmental protection, sustainability and low secondary pollution. Under light conditions, photogenerated electron and hole pairs are generated, and then directly or indirectly degrade the organic pollutants in the liquid phase of the system to achieve the purpose of pollution treatment.

The existing semiconductor materials mainly include TiO ₂ , BiOCl, BiVO ₄ , ZnO, ZnS, CuS, CdS, C ₃ N ₄ and so on. However, the above materials have the following problems in the photocatalytic degradation process: the response to visible light is weak. , The adsorption effect of itself is weak, the recombination rate of photogenerated electrons and holes is high, and the cycle performance is poor.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to provide a zinc ferrite/bismuth vanadate nano-heterostructure composite material and its preparation method and application, the zinc ferrite/bismuth vanadate nano-heterostructure composite material provided by the present invention It has strong response to visible light, strong adsorption performance, low recombination rate of photogenerated electrons and holes, and good cycle performance.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

The invention provides a zinc ferrite/bismuth vanadate nano-heterostructure composite material, comprising BiVO ₄ with a decahedral structure and ZnFe ₂ O ₄ nanoparticles supported on the surface of the BiVO ₄ .

Preferably, the loading amount of the ZnFe ₂ O ₄ nanoparticles is 5-15 wt %.

Preferably, the particle size of the ZnFe ₂ O ₄ nanoparticles is 40-150 nm.

Preferably, the particle size of the BiVO ₄ is 1.5-2 μm.

The present invention also provides the preparation method of the zinc ferrite/bismuth vanadate nano-heterostructure composite material according to the technical solution, comprising the following steps:

Mixing BiVO ₄ , ZnC ₂ O ₄ , water-soluble iron salt and water to obtain a mixed dispersion;

Mixing the mixed dispersion liquid with an inorganic strong base to perform co-precipitation to obtain a precursor;

The precursor is calcined to obtain the zinc ferrite/bismuth vanadate nano-heterostructure composite material.

Preferably, the mass ratio of BiVO ₄ , ZnC ₂ O ₄ and water-soluble iron salt is 1:(0.04-0.1):(0.08-0.2).

Preferably, the pH value of the system after the mixed dispersion liquid and the inorganic strong base are mixed is 8.5-10.

Preferably, the temperature of the co-precipitation is 10-40° C., and the time is 30-40 min.

Preferably, the calcination temperature is 450-550° C., and the time is 1.5-3 h.

The present invention also provides the zinc ferrite/bismuth vanadate nano-heterostructure composite material according to the above technical scheme or the zinc ferrite/bismuth vanadate nano-heterostructure composite material prepared by the preparation method according to the above technical scheme in the photocatalysis Applications in the degradation of organic pollutants.

The invention provides a zinc ferrite/bismuth vanadate nano-heterostructure composite material, comprising BiVO ₄ with a decahedral structure and ZnFe ₂ O ₄ nanoparticles supported on the surface of the BiVO ₄ . In the present invention, BiVO ₄ and ZnFe ₂ O ₄ are combined to form a heterostructure, which promotes the separation of photo-generated electrons and holes, reduces the probability of photo-generated electrons and holes recombination, and improves the photocatalytic performance of the composite material; ZnFe _{2 The} band gap energy of O ₄ is smaller than that of BiVO ₄ . Loading ZnFe ₂ O ₄ on the surface of BiVO ₄ can broaden the photoresponse range and provide good cycle performance. The electrons in the band will stimulate the transition to the conduction band, generate photo-generated electrons and leave photo-generated holes in the valence band accordingly. The photo-generated electrons and holes have reducing and oxidizing properties, which can directly or indirectly degrade organic pollutants. The zinc/bismuth vanadate nanoheterostructure composite has a large specific surface area, which improves its adsorption performance for organic pollutants. Compared with pure phase BiVO ₄ , the composite material provided by the invention has stronger visible light response, lower photogenerated carrier recombination rate, better visible light catalytic degradation performance and good cycle performance, and has good application prospect. As shown in the results of the examples of the present invention, the visible light response range of the zinc ferrite/bismuth vanadate nano-heterostructure composite material provided by the present invention is 420-528 nm, the degradation rate of rhodamine B is as high as 98%, and it is recycled 4 times. The degradation rate of Rhodamine B was still as high as 92.8%, and the photocatalytic degradation performance was only reduced by 5.3%.

The invention provides a preparation method of a zinc ferrite/bismuth vanadate nano-heterostructure composite material, comprising the following steps: mixing BiVO ₄ , ZnC ₂ O ₄ , a water-soluble iron salt and water to obtain a mixed dispersion; The mixed dispersion liquid is mixed with an inorganic strong base for co-precipitation to obtain a precursor; the precursor is calcined to obtain a zinc ferrite/bismuth vanadate nano-heterostructure composite material. The preparation method provided by the invention has simple operation, uses water as a solvent, is green and environmentally friendly, and is suitable for industrial production.

Description of drawings

Fig. 1 is the SEM image of BiVO ₄ prepared in Comparative Example 1;

Fig. 2 is the SEM image of ZnFe ₂ O ₄ prepared in Comparative Example 2;

Fig. 3 is the SEM image of 7.5wt% ZnFe ₂ O ₄ /BiVO ₄ prepared in Example 2;

Fig. 4 is the UV-Vis DRS spectra of BiVO ₄ prepared in Comparative Example 1, ZnFe ₂ O ₄ prepared in Comparative Example 2 and 7.5wt% ZnFe ₂ O ₄ /BiVO ₄ prepared in Example 2;

5 is the band gap energy spectrum of BiVO ₄ prepared in Comparative Example 1, ZnFe ₂ O ₄ prepared in Comparative Example 2 and 7.5wt% ZnFe ₂ O ₄ /BiVO ₄ prepared in Example 2;

6 is a graph showing the degradation effect of BiVO ₄ prepared in Comparative Example 1, ZnFe ₂ O ₄ /BiVO ₄ prepared in Examples 1 to 4, and ZnFe ₂ O ₄ prepared in Comparative Example 2 on Rhodamine B, wherein 5wt% ZnFe ₂ O ₄ /BiVO ₄ represents Example 1, 7.5wt% ZnFe ₂ O ₄ /BiVO ₄ represents Example 2, 10wt% ZnFe ₂ O ₄ /BiVO ₄ represents Example 3, 12.5wt% ZnFe ₂ O ₄ /BiVO ₄ is representative embodiment 1;

7 is a graph showing the cyclic degradation effect of 7.5wt% ZnFe ₂ O ₄ /BiVO ₄ prepared in Example 2 on Rhodamine B.

Detailed ways

The invention provides a zinc ferrite/bismuth vanadate nano-heterostructure composite material (abbreviated as ZnFe ₂ O ₄ /BiVO ₄ ), comprising BiVO ₄ with a decahedral structure and ZnFe ₂ supported on the surface of the BiVO _{4 O4} nanoparticles.

In the present invention, the particle size of the ZnFe ₂ O ₄ nanoparticles is preferably 40-150 nm, more preferably 50-100 nm; the loading amount of the ZnFe ₂ O ₄ nanoparticles is preferably 5-15 wt %, more preferably 7.5 ~12.5 wt%.

In the present invention, the particle size of the BiVO ₄ is preferably 1.5-2 μm, more preferably 1.6-1.8 μm. In the present invention, the BiVO ₄ has a decahedral structure and a large specific surface area, which can improve the bonding strength with the ZnFe ₂ O ₄ nanoparticles.

In the present invention, the ZnFe ₂ O ₄ nanoparticles are supported on the surface of BiVO ₄ by adsorption.

The present invention also provides the preparation method of the zinc ferrite/bismuth vanadate nano-heterostructure composite material according to the technical solution, comprising the following steps:

Mixing BiVO ₄ , ZnC ₂ O ₄ , water-soluble iron salt and water to obtain a mixed dispersion;

Mixing the mixed dispersion liquid with an inorganic strong base to perform co-precipitation to obtain a precursor;

The precursor is calcined to obtain the zinc ferrite/bismuth vanadate nano-heterostructure composite material.

In the present invention, unless otherwise specified, all raw material components are commercially available commodities well known to those skilled in the art.

In the present invention, the BiVO ₄ preferably refers to the literature (Li JQ, Zhou J, Hao HJ, et al. Silver-modified specific (040) facet of BiVO ₄ with enhanced photoelectrochemical performance [J]. Materials Letters 170 (2016) 163 -166.) prepared, specifically, comprising the following steps: dissolve 5mmol of bismuth nitrate pentahydrate in 20mL of nitric acid solution with a concentration of 2mol/L and stir for 30min, denoted as solution A; get 5mmol of ammonium metavanadate and dissolve in 20 mL of sodium hydroxide solution with a concentration of 2 mol/L was stirred for 30 min, and recorded as solution B; solution B was added dropwise to solution A under stirring and continued to stir at room temperature for 2 h; then 2 mL of glacial acetic acid was added dropwise and continued to be stirred for 1 h; The obtained precursor solution was transferred to a 100 mL PTFE-lined stainless steel autoclave, reacted at 180 °C for 24 h, and then the reaction kettle was cooled to room temperature naturally, centrifuged, and the obtained solid product was sequentially washed with deionized water and After washing with absolute ethanol three times each, the product was dried in a drying oven at 80° C. for 10 h to obtain BiVO ₄ .

In the present invention, BiVO ₄ , ZnC ₂ O ₄ , water-soluble iron salt and water are mixed to obtain a mixed dispersion liquid.

In the present invention, the water-soluble iron salt preferably includes ferric nitrate nonahydrate (Fe(NO ₃ ) ₃ ·9H ₂ O), ferric sulfate or ferric chloride, more preferably ferric nitrate nonahydrate. In the present invention, the mass ratio of BiVO ₄ , ZnC ₂ O ₄ and water-soluble iron salt is preferably 1:(0.04-0.1):(0.08-0.2), more preferably 1:(0.05-0.08):( 0.1 to 0.15), most preferably 1:0.06:0.12.

In the present invention, the mixing is preferably ultrasonic mixing, and the power of the ultrasonic mixing is not particularly limited in the present invention, as long as the raw materials can be mixed uniformly. In the present invention, the mixing sequence is preferably the first ultrasonic mixing of BiVO ₄ and part of water to obtain BiVO ₄ dispersion; the second ultrasonic mixing of ZnC ₂ O ₄ , water-soluble iron salt and remaining water to obtain ZnC ₂ O ₄ /iron salt solution; the ZnC ₂ O ₄ /iron salt solution was added dropwise to the BiVO ₄ dispersion for the third ultrasonic mixing. The present invention does not limit the amount of the part of the water, as long as BiVO ₄ can be uniformly dispersed in water. In the embodiment of the present invention, the concentration of the BiVO ₄ dispersion is preferably 0.008 g/mL. The present invention does not specifically limit the amount of the remaining water, as long as ZnC ₂ O ₄ and water-soluble iron salt can be dissolved in water. In the embodiment of the present invention, the ZnC ₂ O ₄ /iron salt solution in the The concentration of ₂ O ₄ is preferably 0.015-0.03 mmol/mL, more preferably 0.02 mmol/mL, and the concentration of the iron salt is preferably 0.03-0.06 mmol/mL, more preferably 0.04 mmol/mL. In the present invention, the temperature of the first ultrasonic mixing, the second ultrasonic mixing and the third ultrasonic mixing is preferably room temperature; the time of the ultrasonic mixing is independently preferably 7-15 min, more preferably 10 min. The present invention does not have a special limitation on the speed of the dropwise addition, and it can be added dropwise.

After the mixed dispersion liquid is obtained, the present invention mixes the mixed dispersion liquid with an inorganic strong base to perform co-precipitation to obtain a precursor.

In the present invention, the inorganic strong base preferably includes hydroxide, more preferably includes sodium hydroxide or potassium hydroxide, more preferably sodium hydroxide. In the present invention, the inorganic strong base is preferably used in the form of an inorganic strong base solid or an inorganic strong base solution. In the present invention, the concentration of the inorganic strong alkali solution is preferably 1-2 mol/L, more preferably 2 mol/L. The present invention does not specifically limit the amount of the inorganic strong base, and the pH value of the system after the mixed dispersion liquid and the inorganic strong base are mixed may be 8.5-10, and the pH value is more preferably 9-9.5.

In the present invention, the mixing is preferably ultrasonic mixing, and the power of the ultrasonic mixing is not particularly limited in the present invention, as long as the raw materials can be mixed uniformly. In the present invention, the temperature of the ultrasonic mixing is preferably room temperature; the time of the ultrasonic mixing is preferably 7-15 min, more preferably 10 min. In the present invention, during the mixing process, zinc ions and iron ions are adsorbed on the surface of BiVO ₄ .

In the present invention, the temperature of the co-precipitation is preferably 10-40° C. In the embodiment of the present invention, the co-precipitation is preferably carried out at room temperature; the time of the co-precipitation is preferably 30-40 min, and more Preferably it is 32～38min, most preferably 35min. In the present invention, in the co-precipitation process, zinc ions and iron ions co-precipitate with hydroxide in situ on the surface of bismuth vanadate to form a uniform co-precipitate of zinc hydroxide and iron hydroxide.

After the co-precipitation, the present invention preferably further includes performing solid-liquid separation on the obtained co-precipitation system, and sequentially washing the obtained solid product with water, alcohol and drying to obtain a precursor. The method of the solid-liquid separation is not particularly limited in the present invention, and a solid-liquid separation method well known to those skilled in the art may be adopted, such as filtration. In the present invention, the number of times of the water washing is preferably one time, and the number of times of the alcohol washing is preferably one time; the alcohol washing is preferably ethanol washing. In the present invention, the amount of water used for water washing and the amount of alcohol used for alcohol washing are not particularly limited, as long as unreacted raw materials and impurities on the surface of the solid product can be removed. In the present invention, the drying is preferably drying, and the drying temperature is preferably 60-90°C, more preferably 70-80°C; the drying time is preferably 8-16h, more preferably 10-12h .

After the precursor is obtained, in the present invention, the precursor is calcined to obtain a zinc ferrite/bismuth vanadate nano-heterostructure composite material.

In the present invention, the calcination temperature is preferably 450-550°C, more preferably 480-520°C, and most preferably 500°C; the heating rate of the precursor from room temperature to the calcining temperature is preferably 5-15°C °C/min, more preferably 8-10 °C/min; start timing when the temperature rises to the calcination temperature, the calcination time is preferably 1.5-3h, more preferably 2-2.5h, most preferably 2h. In the present invention, during the calcination process, the uniform co-precipitate composed of zinc hydroxide and iron hydroxide in the precursor is decomposed to form ZnFe ₂ O ₄ nanoparticles, and ZnFe ₂ O ₄ nanoparticles and BiVO ₄ form ZnFe ₂ O ₄ /BiVO ₄ nanoheterostructure composites.

The present invention also provides the zinc ferrite/bismuth vanadate nano-heterostructure composite material according to the above technical scheme or the zinc ferrite/bismuth vanadate nano-heterostructure composite material prepared by the preparation method according to the above technical scheme in the photocatalysis Applications in the degradation of organic pollutants.

The present invention does not specifically limit the types and sources of the organic pollutants, such as dyes. In the embodiments of the present invention, it is preferable to use rhodamine as the organic pollutant to verify the zinc ferrite/bismuth vanadate nano-heterostructure composite material Degradation performance for organic pollutants.

In the present invention, the application method preferably includes the following steps: mixing the zinc ferrite/bismuth vanadate nano-heterostructure composite material with a solution containing organic pollutants, performing dark treatment, and then performing light irradiation under visible light irradiation. Catalytic reaction.

In the present invention, the concentration of the solution containing organic pollutants is not particularly limited, specifically, 10 mg/L. The present invention has no special limitation on the mass ratio of the zinc ferrite/bismuth vanadate nano-heterostructure composite material and organic pollutants, and is preferably adjusted according to the actual situation; The mass ratio of the bismuth vanadate nanoheterostructure composite material and the organic pollutants is preferably 1:40. In the present invention, the time of the dark treatment is preferably 20-40 min, more preferably 30 min. In the present invention, the visible light is preferably provided by a 350W xenon lamp equipped with a 420nm filter. In the present invention, the temperature of the photodegradation is preferably room temperature.

The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1

Dissolve 5mmol of bismuth nitrate pentahydrate in 20mL of nitric acid solution with a concentration of 2mol/L and stir for 30min, denoted as solution A; take 5mmol of ammonium metavanadate and dissolve it in 20mL of sodium hydroxide solution with a concentration of 2mol/L and stir for 30min , denoted as solution B; add solution B dropwise to solution A under stirring and continue to stir at room temperature for 2 h; then add 2 mL of glacial acetic acid dropwise and continue to stir for 1 h; transfer the obtained precursor solution to 100 mL of polytetrafluoroethylene lining In the stainless steel autoclave, the reaction was carried out at 180 °C for 24 hours, and then the reaction kettle was naturally cooled to room temperature, and centrifuged. It was dried at 80 °C for 10 h to obtain BiVO ₄ .

0.4g BiVO ₄ and 50mL deionized water were ultrasonically mixed for 10min to obtain BiVO ₄ dispersion; 0.018g ZnC ₂ O ₄ ·2H ₂ O, 0.066g Fe(NO ₃ ) ₃ ·9H ₂ O and 5mL deionized water were ultrasonically mixed for 10min , to obtain a ZnC ₂ O ₄ /Fe(NO ₃ ) ₃ solution; the ZnC ₂ O ₄ /Fe(NO ₃ ) ₃ solution was added dropwise to the BiVO ₄ dispersion to obtain a mixed dispersion; at room temperature, ultrasonically mixed Under the conditions, a NaOH solution with a concentration of 2mol/L was added dropwise to the mixed dispersion to a pH of 9, co-precipitated for 35min after ultrasonication for 10min, and then filtered, and the obtained solid product was washed with water and alcohol, and then The precursor was dried at 80 °C for 10 h to obtain a precursor; the precursor was heated to 500 °C at a rate of 8 °C/min and then calcined for 2 h to obtain a zinc ferrite/bismuth vanadate nano-heterostructure composite material (abbreviated as 5wt% ZnFe ₂ O ₄ /BiVO ₄ , where 5 wt % means that the loading amount of ZnFe ₂ O ₄ is 5 wt %).

Examples 2 to 4

The zinc ferrite/bismuth vanadate nano-heterostructure composite material was prepared according to the method of Example 1. The different preparation conditions of Examples 2 to 4 and Example 1 are shown in Table 1:

Table 1 Preparation Conditions of Examples 1 to 4

Comparative Example 1

Take BiVO ₄ prepared in Example 1 as Comparative Example 1.

Comparative Example 2

Dissolve 2 mg of zinc acetate dihydrate and 4 mg of ferric nitrate nonahydrate in 40 mL of deionized water, dissolve by ultrasonic, and then add 2 mol/L of sodium hydroxide under stirring to adjust the pH to 9, carry out co-precipitation for 30 min, and filter the obtained solid. After washing with water, 10 g of the product was dried at 80°C, and then calcined at 500°C for 2 hours to obtain ZnFe ₂ O ₄ .

The SEM image of BiVO ₄ prepared in Comparative Example 1 is shown in Figure 1, the SEM image of ZnFe ₂ O ₄ prepared in Comparative Example 2 is shown in Figure 2, and the 7.5wt% ZnFe ₂ O ₄ /BiVO ₄ prepared in Example 2 The SEM image is shown in Figure 3. It can be seen from Figures 1 to 3 that the pure phase BiVO ₄ has a particle size of 1.5 to 2 μm and has a decahedral structure, and the pure phase ZnFe ₂ O ₄ is granular. The ZnFe ₂ O ₄ /BiVO ₄ prepared by the preparation method provided by the present invention is in BiVO _{4 The} surface was successfully loaded with _ZnFe2O4 nanoparticles with a heterostructure.

The UV-Vis DRS spectra of 7.5wt% ZnFe ₂ O ₄ /BiVO ₄ prepared in Example 2, BiVO ₄ prepared in Comparative Example 1 and ZnFe ₂ O ₄ prepared in Comparative Example 2 are shown in Figure 4, and the band gap energy spectrum The diagram is shown in Figure 5. It can be seen from Figures 4-5 that the visible light response range of 7.5wt% ZnFe ₂ O ₄ /BiVO ₄ is 420-528 nm. Compared with BiVO ₄ , the band gap energy of 7.5wt% ZnFe ₂ O ₄ /BiVO ₄ is reduced.

Application example 1

Taking Rhodamine B as the target degradation product, an aqueous solution of Rhodamine B (C ₀ =10 mg/L, 40 mL) was prepared, without adding a photocatalyst (blank), and adding 10 mg of zinc ferrite/bismuth vanadate prepared in Examples 1 to 4 respectively The nano-heterostructure composite (ZnFe ₂ O ₄ /BiVO ₄ ), BiVO ₄ prepared in Comparative Example 1 and ZnFe ₂ O ₄ prepared in Comparative Example 2 were used as photocatalysts. The photocatalytic reaction was carried out under the irradiation of the 350W xenon lamp of the light sheet, the concentration (C _t ) of Rhodamine B was sampled every 20 minutes, and the degradation rate of Rhodamine B was calculated=(1-C _t /C ₀ )*100%, the test result As shown in Table 2 and Figure 6.

The degradation rate (%) of table 2 photocatalyst to rhodamine B

It can be seen from Figure 6 and Table 2 that after 120min of degradation, the degradation rate of BiVO ₄ to Rhodamine B is 23.9%, the degradation rate of ZnFe ₂ O ₄ to Rhodamine B is 17.3%, and the ZnFe 2 O 4 / ZnFe ₂ O ₄ / The degradation rate of rhodamine B by the BiVO ₄ nano-heterostructure composite material is 82.2-98.0%, indicating that compared with BiVO ₄ and ZnFe ₂ O ₄ , the ZnFe ₂ O ₄ /BiVO ₄ nano-heterostructure prepared by the present invention The degradation rate of rhodamine B was significantly improved by the composites.

Application example 2

The 7.5wt% ZnFe ₂ O ₄ /BiVO ₄ prepared in Example 2 was degraded to Rhodamine B according to the method of Application Example 1. After the degradation was completed, the 7.5 wt % ZnFe ₂ O ₄ /BiVO ₄ was centrifuged to separate the obtained solid catalyst. The materials were washed, dried and collected in sequence to obtain a recovered photocatalyst, and then the next photocatalytic degradation experiment was carried out according to the method of application example 1; a total of 4 times of recycling, the cycle performance of 7.5wt% ZnFe ₂ O ₄ /BiVO ₄ is shown in the figure 7 is shown. It can be seen from Fig. 7 that the degradation rates of rhodamine B after 1 to 4 cycles of 7.5wt% ZnFe ₂ O ₄ /BiVO ₄ are 98.0%, 97.5%, 96.3% and 92.8% in turn, indicating that the ZnFe ₂ The O ₄ /BiVO ₄ nanoheterostructure composite has good recycling performance.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. A zinc ferrite/bismuth vanadate nano heterostructure composite material comprises BiVO with a decahedral structure₄And is loaded on the BiVO₄ZnFe of surface₂O₄And (3) nanoparticles.

2. The zinc ferrite/bismuth vanadate nano-heterostructure composite material of claim 1, wherein the ZnFe is present₂O₄The loading amount of the nanoparticles is 5-15 wt%.

3. The zinc ferrite/bismuth vanadate nano-heterostructure composite material according to claim 1 or 2, wherein the ZnFe is present₂O₄The particle size of the nano particles is 40-150 nm.

4. The zinc ferrite/bismuth vanadate nano-heterostructure composite material of claim 1, wherein the BiVO is₄The particle size of (A) is 1.5 to 2 μm.

5. The preparation method of the zinc ferrite/bismuth vanadate nano-heterostructure composite material according to any one of claims 1 to 4, which comprises the following steps:

BiVO (bismuth oxide) is added₄、ZnC₂O₄Mixing the water-soluble ferric salt and water to obtain a mixed dispersion liquid;

mixing the mixed dispersion liquid with inorganic strong base, and performing coprecipitation to obtain a precursor;

and calcining the precursor to obtain the zinc ferrite/bismuth vanadate nano heterostructure composite material.

6. The method according to claim 5, wherein the BiVO is BiVO₄、ZnC₂O₄And the mass ratio of the water-soluble iron salt to the water-soluble iron salt is 1: (0.04-0.1): (0.08-0.2).

7. The preparation method according to claim 5, wherein the pH value of the mixed dispersion liquid and the inorganic strong base is 8.5-10.

8. The preparation method according to claim 5, wherein the temperature of the coprecipitation is 10 to 40 ℃ and the time is 30 to 40 min.

9. The preparation method of claim 5, wherein the calcining temperature is 450-550 ℃ and the calcining time is 1.5-3 h.

10. The use of the zinc ferrite/bismuth vanadate nano-heterostructure composite material according to any one of claims 1 to 4 or the zinc ferrite/bismuth vanadate nano-heterostructure composite material prepared by the preparation method according to any one of claims 5 to 9 for photocatalytic degradation of organic pollutants.

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