阅读说明：本技术 一种BiVO4纳米片及其制备方法和应用 (BiVO4Nanosheet and preparation method and application thereof ) 是由 谈国强 杨迁 毕钰 王敏 张碧鑫 冯帅军 任慧君 夏傲 于 2021-09-29 设计创作，主要内容包括：本发明提供一种BiVO-(4)纳米片及其制备方法和应用,包括以下步骤：步骤1,将Bi(NO-(3))-(3)·5H-(2)O溶于稀HNO-(3)溶液中,搅拌至澄清,然后加入NH-(4)VO-(3),搅拌,形成前驱液；其中,前驱液的pH值控制在小于0.01；步骤2,将前驱液在50～60℃下水热反应21～26h,制得红色沉淀,将该红色沉淀用去离子水洗涤后再加入无水乙醇静置,制得深绿色沉淀；步骤3,将深绿色沉淀用无水乙醇洗涤,干燥,制得BiVO-(4)纳米片。制备得到的BiVO-(4)纳米片比表面积增大,黑暗条件下吸附性能增强。(The invention provides a BiVO 4 The nano sheet and the preparation method and the application thereof comprise the following steps: step 1, adding Bi (NO) 3 ) 3 ·5H 2 O dissolved in dilute HNO 3 Stirring the solution until the solution is clear, and then adding NH 4 VO 3 Stirring to form precursor liquid; wherein the pH value of the precursor liquid is controlled to be less than 0.01; step 2, carrying out hydrothermal reaction on the precursor solution at the temperature of 50-60 ℃ for 21-26 h to prepare red precipitate, washing the red precipitate with deionized water, then adding absolute ethyl alcohol, and standing to prepare dark green precipitate; step 3, washing the dark green precipitate with absolute ethyl alcohol, and drying to prepare BiVO 4 Nanosheets. BiVO obtained by preparation 4 Ratio of nanosheetThe surface area is increased, and the adsorption performance under dark conditions is enhanced.)

1. BiVO₄The preparation method of the nanosheet is characterized by comprising the following steps:

step 1, adding Bi (NO)₃)₃·5H₂O dissolved in dilute HNO₃Stirring the solution until the solution is clear, and then adding NH₄VO₃Stirring to form precursor liquid; wherein the pH value of the precursor liquid is controlled to be less than 0.01;

step 2, carrying out hydrothermal reaction on the precursor solution at the temperature of 50-60 ℃ for 21-26 h to prepare red precipitate, washing the red precipitate with deionized water, then adding absolute ethyl alcohol, and standing to prepare dark green precipitate;

step 3, washing the dark green precipitate with absolute ethyl alcohol, and drying to prepare BiVO₄Nanosheets.

2. BiVO according to claim 1₄The preparation method of the nano-sheet is characterized in that in the step 1, dilute HNO is adopted₃The concentration of the solution is 1.5-2.0 mol/L.

3. BiVO according to claim 1₄A process for producing a nanosheet, wherein in step 1, Bi (NO)₃)₃·5H₂O and NH₄VO₃Is 1: 1.

4. BiVO according to claim 1₄The preparation method of the nanosheet is characterized in that in the step 1, the stirring time is 120-150 min.

5. The Bi according to claim 1VO₄The preparation method of the nanosheet is characterized in that in the step 2, the standing time is 24-48 h.

6. BiVO according to claim 1₄The preparation method of the nanosheet is characterized in that in the step 3, drying is carried out at a constant temperature of 50-60 ℃ for 12-15 hours.

7. BiVO obtained by the production method according to any one of claims 1 to 6₄Nanosheets.

8. BiVO of claim 7₄The nano-sheet is applied to the aspect of adsorbing organic pollutants.

9. BiVO of claim 7₄The nano-sheet is applied to photocatalytic degradation of organic pollutants.

Technical Field

The invention belongs to the field of materials with environmental protection functions, and relates to BiVO with good adsorption capacity in dark₄Nanosheet and preparation method and application thereof.

Background

BiVO₄There are mainly three crystal structures, namely a tetragonal scheelite structure, a monoclinic scheelite structure and a tetragonal zircon structure. The tetragonal phase has an absorption band mainly in the ultraviolet region, and the monoclinic phase BiVO₄In addition to the absorption band in the ultraviolet region, there is also a distinct absorption band in the visible region. Monoclinic phase BiVO₄Absorption in the ultraviolet region is mainly formed by electron transition from the O2p orbital to the V3d orbital, and monoclinic phase BiVO₄The absorption band in the visible region is mainly generated by electron transition from the Bi6s orbital or the hybrid orbital of Bi6s and O2p to the V3d orbital. The energy gap of monoclinic phase bismuth vanadate is about 2.4eV, which is very close to the center of solar spectrum, and the absorption threshold can be prolonged to about 5203 nm. Monoclinic phase BiVO₄Belongs to the 12/a type space group, and the specific unit cell parameters are as follows: 5.195, 11.701, 5.092, 90.0 ° α, 90.38 ° β, and 90.0 ° γ. Monoclinic phase BiVO₄Wherein each V atom and 4O atoms are bonded to form V-O, the V-O tetrahedrons are not in contact with each other, each Bi atom and 6O atoms are bonded to form Bi-O octahedrons, the coordination polyhedron can be regarded as being formed by two tetrahedrons of the same size penetrating each other, the Bi-O octahedrons alternate with adjacent edges, and one Bi atom surrounds eight V-O tetrahedrons, which share one O atom.

However, BiVO with decahedron morphology prepared by low-temperature hydrothermal method is available₄The semiconductor material has the problems of small specific surface area, poor adsorption performance in darkness, low light quantum utilization rate and the like.

Disclosure of Invention

The invention aims to provide a BiVO₄Nanosheet, preparation method and application thereof, and BiVO prepared from nanosheet₄The specific surface area of the nano sheet is increased, and the adsorption performance under dark conditions is enhanced.

The invention is realized by the following technical scheme:

BiVO₄A method of making nanoplatelets comprising the steps of:

step 1, adding Bi (NO)₃)₃·5H₂O dissolved in dilute HNO₃Stirring the solution until the solution is clear, and then adding NH₄VO₃Stirring to form precursor liquid; wherein the pH value of the precursor liquid is controlled to be less than 0.01;

step 2, carrying out hydrothermal reaction on the precursor solution at the temperature of 50-60 ℃ for 21-26 h to prepare red precipitate, washing the red precipitate with deionized water, then adding absolute ethyl alcohol, and standing to prepare dark green precipitate;

step 3, washing the dark green precipitate with absolute ethyl alcohol, and drying to prepare BiVO₄Nanosheets.

Preferably, in the step 1, HNO is diluted₃The concentration of the solution is 1.5-2.0 mol/L.

Preferably, in said step 1, Bi (NO)₃)₃·5H₂O and NH₄VO₃Is 1: 1.

Preferably, in the step 1, the stirring time is 120-150 min.

Preferably, in the step 2, the standing time is 24-48 h.

Preferably, in the step 3, the drying is carried out at a constant temperature of 50-60 ℃ for 12-15 hours.

BiVO obtained by adopting the preparation method₄Nanosheets.

The BiVO₄The nano-sheet is applied to the aspect of adsorbing organic pollutants.

The BiVO₄The nano-sheet is applied to photocatalytic degradation of organic pollutants.

Compared with the prior art, the invention has the following beneficial technical effects:

the invention provides a BiVO₄A method for preparing nano-sheets by hydrothermal method under strong acidic conditionBiVO preparation₄Nanosheets, and a large amount of H in solution⁺Make part of Bi³⁺And VO₄ ^3-Does not participate in the reaction to form BiVO with partial defects₄To make a large amount of H⁺Adsorbing to BiVO₄Resulting in a red precipitate in color, followed by soaking in absolute ethanol, a large amount of OH is adsorbed to BiVO₄Causing the precipitate to change from red to dark green. Because the pH value of the precursor solution is controlled to be less than 0.01, the precursor solution contains a large amount of H⁺Preferential adsorption on BiVO₄The (-121) and (121) crystal planes of the crystal nucleus will reduce the surface energy, the growth rate of the (-121) and (121) crystal planes is reduced, and BiVO is formed through long-time hydrothermal growth₄The particles grow further to BiVO at the expense of small particles₄Nanosheets. The obtained BiVO₄The nano-sheet has large specific surface area and many active sites, is favorable for adsorbing and degrading pollutants, and improves BiVO₄Adsorption performance in dark conditions.

Furthermore, compared with other methods, the low-temperature hydrothermal method has the advantages of simple preparation process, low price, capability of directly obtaining powder with good crystallization, easiness in regulating and controlling the grain size and the like.

BiVO prepared by the invention₄The adsorption rate of the nano-sheets in the dark is high, and the BiVO is greatly improved₄The dark adsorption performance of the composite material can be used for photocatalytic degradation of organic pollutants.

Drawings

FIG. 1 is BiVO prepared by the present invention₄XRD diffraction pattern of the nano-sheet;

FIG. 2 is BiVO prepared by the present invention₄SEM images of the nanoplatelets;

FIG. 3 is BiVO prepared by the present invention₄The nano sheet degrades a RhB degradation pattern under visible light;

FIG. 4 is BiVO prepared by the present invention₄The nanoplate absorbs the absorption pattern of RhB in dark twice in a circulating manner.

Detailed Description

The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.

Example 1

Step 1, adding 6mmoL Bi (NO)₃)₃·5H₂O is dissolved in 35mL of HNO 2mol/L at a uniform and slow speed under the stirring condition₃Stirring for 30min until the solution is clear, and slowly adding 6mmoL NH₄VO₃Stirring for 150min until the pH value of the solution is less than 0.01 to form a precursor solution;

step 2, carrying out hydrothermal reaction on the precursor solution at 60 ℃ for 26h to obtain red precipitate, washing the precipitate for 3 times, adding absolute ethyl alcohol, and standing for 24h to obtain dark green precipitate;

step 3, washing the dark green precipitate for 3 times by using absolute ethyl alcohol, and drying for 15 hours at the temperature of 60 ℃ to prepare flaky BiVO₄Nanosheets.

Example 2

Step 1, adding 6mmoL Bi (NO)₃)₃·5H₂O is dissolved in 35mL of 1.9mol/L HNO at a uniform and slow speed under the stirring condition₃Stirring for 30min until the solution is clear, and slowly adding 6mmoL NH₄VO₃Stirring for 145min until the pH of the solution is always less than 0.01 to form a precursor solution;

step 2, carrying out hydrothermal reaction on the precursor solution at 58 ℃ for 25h to obtain red precipitate, washing the precipitate for 4 times, adding absolute ethyl alcohol, and standing for 30h to obtain dark green precipitate;

step 3, washing the dark green precipitate with absolute ethyl alcohol for 4 times, and drying at 58 ℃ for 14.5 hours to prepare flaky BiVO₄Nanosheets.

Example 3

Step 1, adding 6mmoL Bi (NO)₃)₃·5H₂O is dissolved in 35mL of 1.8mol/L HNO at a uniform and slow speed under the stirring condition₃Stirring for 30min until the solution is clear, and slowly adding 6mmoL NH₄VO₃Stirring for 140min until the pH value of the solution is always less than 0.01 to form precursor solution;

step 2, carrying out hydrothermal reaction on the precursor solution at 56 ℃ for 24 hours to obtain red precipitate, washing the precipitate for 5 times, adding absolute ethyl alcohol, and standing for 35 hours to obtain dark green precipitate;

step 3, washing the dark green precipitate for 5 times by using absolute ethyl alcoholDrying at 56 ℃ for 14h to prepare flaky BiVO₄Nanosheets.

Example 4

Step 1, adding 6mmoL Bi (NO)₃)₃·5H₂O is dissolved in 35mL of 1.7mol/L HNO at a uniform and slow speed under the stirring condition₃Stirring for 30min until the solution is clear, and slowly adding 6mmoL NH₄VO₃Stirring for 135min until the pH value of the solution is always less than 0.01 to form precursor solution;

step 2, carrying out hydrothermal reaction on the precursor solution at 54 ℃ for 23h to obtain red precipitate, washing the precipitate for 5 times, adding absolute ethyl alcohol, and standing for 40h to obtain dark green precipitate;

step 3, washing the dark green precipitate for 5 times by using absolute ethyl alcohol, and drying at 54 ℃ for 13.5 hours to prepare flaky BiVO₄Nanosheets.

Example 5

Step 1, adding 6mmoL Bi (NO)₃)₃·5H₂O is dissolved in 35mL of 1.6mol/L HNO at a uniform and slow speed under the stirring condition₃Stirring for 30min until the solution is clear, and slowly adding 6mmoL NH₄VO₃Stirring for 130min until the pH value of the solution is always less than 0.01 to form precursor solution;

step 2, carrying out hydrothermal reaction on the precursor solution at 52 ℃ for 22h to prepare red precipitate, washing the precipitate for 4 times, adding absolute ethyl alcohol, and standing for 45h to prepare dark green precipitate;

step 3, washing the dark green precipitate with absolute ethyl alcohol for 4 times, and drying at 52 ℃ for 13 hours to prepare flaky BiVO₄Nanosheets.

Example 6

Step 1, adding 6mmoL Bi (NO)₃)₃·5H₂O is dissolved in 35mL of 1.5mol/L HNO at a uniform and slow speed under the stirring condition₃Stirring for 30min until the solution is clear, and slowly adding 6mmoL NH₄VO₃Stirring for 120min until the pH value of the solution is always less than 0.01 to form precursor solution;

step 2, carrying out hydrothermal reaction on the precursor solution at 50 ℃ for 21h to obtain red precipitate, washing the precipitate for 3 times, adding absolute ethyl alcohol, and standing for 48h to obtain dark green precipitate;

step 3, washing the dark green precipitate for 3 times by using absolute ethyl alcohol, and drying for 12 hours at 50 ℃ to prepare flaky BiVO₄Nanosheets.

FIG. 1 is BiVO prepared in example 1₄The XRD diffraction pattern of the nano-sheet shows monoclinic phase BiVO at 2 theta, 18.67 degrees, 18.99 degrees, 28.82 degrees and 28.95 degrees₄Characteristic diffraction peaks of (110), (011), (-121) and (121) crystal planes of (PDFNo.14-0688), BiVO₄Growth along the preferred orientation of (-121) and (121) crystal planes, and H in the precursor solution because the pH value of the precursor solution is controlled to be less than 0.01⁺Preferential adsorption on BiVO₄The (-121) and (121) crystal planes of the crystal nuclei and will lower the surface energy. The growth rate of (-121) and (121) crystal faces is reduced, and BiVO is obtained after long-time hydrothermal growth₄The particles grow further to BiVO at the expense of small particles₄Nanosheets.

FIG. 2 is a nano-flaky BiVO prepared in example 1₄SEM picture of (1), BiVO₄Has 320 × 400nm square flake shape and 200 × 240nm square flake shape, and has large specific surface area, BiVO₄The surface has more active sites, and a mechanism beneficial to pollutant adsorption is formed.

FIG. 3 is BiVO prepared in example 1₄The degradation graph of the nanosheet for degrading RhB under visible light shows that BiVO₄The adsorption rate of the nano-sheet for adsorbing rhodamine B for 30min under a dark condition reaches 80.52%, which shows that the nano-sheet has good adsorption performance.

FIG. 4 is BiVO prepared in example 1₄The nanoplate absorbs the absorption figure of RhB in two cycles under the dark condition. The adsorption rate of adsorbing rhodamine B for 35min through treatment under the dark condition for the first time reaches 90.81%, the adsorption rate of adsorbing rhodamine B for 35min through treatment under the dark condition for the second time reaches 60.27%, and because the adsorption under the dark condition for the first time is carried out, the pollutant occupies part of active sites on the surface of the sample, and because the sample has good adsorption performance, the pollutant is not easy to desorb after being adsorbed, no more active sites are provided for the pollutant to enable the pollutant to be adsorbed when the adsorption cycle is carried out for the second time, and then the adsorption rate for the second time is less than the adsorption rate for the first time. Description of BiVO₄Nano-sheetHas good circulating adsorption.

The above-described details are further intended to describe the present invention in connection with the particular preferred embodiments thereof, and it is not intended to limit the invention to all or the only embodiments disclosed, and all equivalents and modifications which may occur to those skilled in the art upon reading the present specification are intended to be encompassed by the present claims.