CN115870010A - Bismuth titanate nanosheet/UiO-66-NH containing bismuth vacancies 2 Heterojunction and preparation method and application thereof - Google Patents
Bismuth titanate nanosheet/UiO-66-NH containing bismuth vacancies 2 Heterojunction and preparation method and application thereof Download PDFInfo
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- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 16
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Abstract
The invention discloses a bismuth titanate nano-sheet/UiO-66-NH containing bismuth vacancy 2 Heterojunction and preparation method and application thereof. Mixing titanium dioxide, bismuth oxide and inorganic salt, calcining to obtain a bismuth titanate nanosheet, and then immersing the bismuth titanate nanosheet in an ionic eutectic solvent to obtain a bismuth titanate nanosheet containing bismuth vacancies; the bismuth titanate nano-sheet containing the bismuth vacancy, diaminoterephthalic acid, zirconium chloride and acetic acid are subjected to hydrothermal reaction to obtain bismuth titanate nano-sheet/UiO-66-NH containing the bismuth vacancy 2 A heterojunction. The bismuth vacancy is constructed on the bismuth titanate nano-sheet by adopting a simple ionic eutectic solvent leaching method, so that the titanium can be effectively enhancedAsymmetry of bismuth acid nano-sheet crystal structure, taking bismuth titanate nano-sheet containing bismuth vacancy as substrate, and hydrothermally growing UiO-66-NH 2 The catalyst constructed by the nano particles has excellent piezoelectric catalytic performance.
Description
Technical Field
The invention relates to the technical field of inorganic/organic nano composite materialsIn particular to bismuth titanate nano-sheets/UiO-66-NH containing bismuth vacancies 2 The preparation of the heterojunction and the application thereof in the catalytic oxidation of formaldehyde.
Background
Formaldehyde is one of the main indoor pollutants at present and widely exists in various building and decorative materials. Long term exposure to even air with very low formaldehyde gas content can have irreversible adverse effects on the respiratory system of the human body. The catalytic oxidation method can decompose formaldehyde gas into harmless carbon dioxide and water using active oxygen species, and is a method of purifying formaldehyde gas, which has been receiving attention from researchers due to its long-lasting effect. The methods currently used for the catalytic oxidation of formaldehyde gas are mainly photocatalytic and thermocatalytic. However, the traditional photocatalyst has a narrow light absorption range and serious recombination of photo-generated electron-hole pairs, and the thermal catalyst generally needs to be supported by noble metals and has higher cost. In addition to solar and thermal energy, there are many other renewable energy sources in nature, such as wind, tidal, hydro, etc. How to solve the problem of environmental pollution by using the mechanical energy becomes a focus of attention, and the birth of the piezoelectric catalytic technology provides an efficient green method for using the mechanical energy in the environment. Under the action of mechanical stress, the piezoelectric material can generate a piezoelectric potential to induce free electrons and holes in the piezoelectric material to reach the surface of the material to participate in redox reaction, so that the purpose of degrading pollutants is achieved. With the development of nanotechnology, perovskite bismuth titanate has been paid attention to by researchers in the field of piezoelectric catalysis due to its unique layered crystal structure and good ferroelectric properties. The prior art discloses methods for improving the piezoelectric performance of bismuth titanate, such as improving the piezoelectric coefficient of bismuth titanate nano-sheets by reducing the thickness of the nano-sheets; enhancing the asymmetry of the crystal structure by introducing oxygen vacancies; the iron polarization is enhanced by coupling corona polarization and surface iodide ion grafting, and the separation and transfer of current carriers are promoted. In the prior art, the catalytic effect of the modified bismuth titanate nano material needs to be improved when formaldehyde gas is oxidized by piezoelectric catalysis.
Disclosure of Invention
The invention aims to provide bismuth titanate sodium containing bismuth vacanciesRice flake/UiO-66-NH 2 A method for fabricating a heterojunction. Takes bismuth titanate nano-sheet containing bismuth vacancy as a substrate and hydrothermally grows UiO-66-NH 2 Bismuth titanate nanosheet/UiO-66-NH containing bismuth vacancies constructed by nanoparticles 2 Heterojunction, unique (Bi) 2 O 2 ) 2+ The charged layer structure with the layers and the anion layers staggered enables the materials to form an interlayer built-in electric field along the c-axis direction; the material has high porosity and large specific surface area, and the introduction of amino further increases the catalytic performance of the material on formaldehyde gas.
In order to achieve the purpose, the invention adopts the following specific technical scheme:
bismuth titanate nanosheet/UiO-66-NH containing bismuth vacancies 2 A heterojunction, the method of making comprising the steps of:
(1) Mixing titanium dioxide, bismuth oxide and inorganic salt, calcining to obtain a bismuth titanate nano sheet, and then immersing the bismuth titanate nano sheet into an ionic eutectic solvent to obtain a bismuth titanate nano sheet containing bismuth vacancies;
(2) Carrying out hydrothermal reaction on a mixture of bismuth titanate nanosheets containing bismuth vacancies, diaminoterephthalic acid, zirconium chloride and acetic acid to obtain bismuth titanate nanosheets/UiO-66-NH containing bismuth vacancies 2 A heterojunction.
The above preparation method is further described as follows:
(1) Mixing and grinding titanium dioxide, bismuth oxide and inorganic salt, then calcining to prepare a bismuth titanate nanosheet, then immersing the bismuth titanate nanosheet in an ionic eutectic solvent consisting of a hydrogen bond donor and a hydrogen bond acceptor, and leaching bismuth atoms from bismuth titanate crystal lattices to form bismuth titanate nanosheets containing bismuth vacancies;
(2) Adding diamino terephthalic acid, zirconium chloride and acetic acid into bismuth titanate nanosheet solution containing bismuth vacancies, and carrying out hydrothermal reaction to prepare bismuth titanate nanosheet/UiO-66-NH containing bismuth vacancies 2 A heterojunction material.
A process for the catalytic oxidation of formaldehyde comprising the steps of: bismuth titanate nano-sheets/UiO-66-NH containing bismuth vacancies 2 The heterojunction is placed in an environment containing formaldehyde, and the catalytic oxidation of the formaldehyde is realized under the ultrasonic condition。
In the technical scheme, in the step (1), the inorganic salt is sodium chloride and potassium chloride; the molar ratio of titanium dioxide to bismuth oxide is 3: 2, the molar ratio of bismuth titanate to sodium chloride to potassium chloride is 1: 40-90, preferably 1: 60; the grinding time is 10 min-60 min; the calcining temperature is 500 ℃ to 1000 ℃, preferably 800 ℃, and the calcining time is 1 to 5 hours, preferably 2 h; preferably, after calcination, washing with water, and then drying, such as vacuum drying at 60 ℃ 12 h, bismuth titanate nanoplatelets are obtained.
In the technical scheme, in the step (1), the hydrogen bond donor is ethylene glycol, the hydrogen bond acceptor is choline chloride, preferably, the molar ratio of the hydrogen bond donor to the hydrogen bond acceptor is (1.5-3) to 1, preferably 2: 1, the hydrogen bond donor and the hydrogen bond acceptor are mixed to form an ionic eutectic solvent at room temperature, the bismuth titanate nanosheet is immersed in the ionic eutectic solvent, reacts at 70-90 ℃ for 2 h-10 h, preferably reacts at 80 ℃ for 4 h, then is washed with water, and then is dried, for example, vacuum-dried at 60 ℃ for 12 h, so that the bismuth titanate nanosheet containing bismuth vacancies is obtained. The invention adopts a simple method of soaking in an ionic eutectic solvent to leach part of bismuth atoms from the bismuth titanate nanosheet to obtain the bismuth titanate nanosheet containing bismuth vacancies, and the vacancies can effectively improve the piezoelectric catalytic performance.
In the technical scheme, in the step (2), the mass ratio of the bismuth titanate nano-sheet containing bismuth vacancy to the diaminoterephthalic acid to the zirconium chloride is (400-1500) to (100-150) to (80-100), preferably (900-1000) to (100-130) to (80-100), such as (950-1000) to (110-120) to (85-95). Preferably, the bismuth titanate nanosheet solution containing bismuth vacancies is an aqueous solution, and the concentration is 300-400 mg/mL; the hydrothermal reaction is carried out for 20 to 30 hours at a temperature of between 80 and 120 ℃, preferably 24 h at 100 ℃, then water and methanol are used for washing, and then drying is carried out, for example, 12 h is carried out at 60 ℃, thus obtaining bismuth titanate nano-sheet/UiO-66-NH containing bismuth vacancy 2 A heterojunction.
The invention has the advantages that:
the invention leaches bismuth atoms from a bismuth titanate crystal lattice using an ionic eutectic solvent to form cationsAnd (5) a defect. The construction of the vacancy changes the geometric structure of the coordination atom, and the catalytic activity is effectively improved. In particular, the invention firstly combines bismuth titanate nano-sheets containing bismuth vacancies with UiO-66-NH 2 Combining the nano particles to construct bismuth titanate nano sheet/UiO-66-NH containing bismuth vacancy 2 The heterojunction and the combined action greatly increase the processing performance of the material on formaldehyde gas, and the removal rate of the material reaches 95.1 percent at normal temperature within 180 minutes.
Drawings
FIG. 1 is a scanning electron microscope image of bismuth titanate nanoplatelets containing bismuth vacancies.
FIG. 2 shows bismuth titanate nanoplatelets/UiO-66-NH containing bismuth vacancies 2 And (3) a scanning electron microscope image and a transmission electron microscope image of the heterojunction, wherein the upper left corner is the transmission electron microscope image.
FIG. 3 is a graph of the piezo-catalytic oxidation of formaldehyde gas in air by the catalyst.
FIG. 4 shows bismuth titanate nanoplatelets/UiO-66-NH containing bismuth vacancies 2 And (3) a cycle curve diagram of the heterojunction on the piezoelectric catalytic oxidation of formaldehyde gas in the air.
FIG. 5 is a graph of the piezoelectric catalytic oxidation of formaldehyde gas for catalysts prepared by different preparation methods.
FIG. 6 is a graph showing the relationship between the effect of bismuth vacancies on the piezoelectric catalytic oxidation of formaldehyde gas.
Detailed Description
Aiming at the defects existing in the practical application of the existing nano piezoelectric catalytic material, the invention constructs the bismuth titanate nano-sheet/UiO-66-NH containing bismuth vacancies by utilizing the preparation methods of an ionic eutectic solvent method, a hydrothermal method and the like 2 Is heterogeneous. Bismuth titanate can generate strong spontaneous polarization in crystals, and contributes to the separation of free carriers. The introduction of the bismuth vacancy enhances the asymmetry of the crystal structure of the material, and further improves the piezoelectric catalytic activity. UiO-66-NH 2 Has higher specific surface area, developed micropore structure and outstanding chemical stability, and in addition, the introduction of amino further increases the processing performance of the material on formaldehyde gas. The aim of catalyzing and oxidizing formaldehyde pollutants in the air is fulfilled through the synergistic effect of composite material adsorption and piezoelectric catalysis.
The raw materials of the invention are all commercial products, the specific preparation operation and the performance test are conventional technologies, and the operation of the invention is carried out in the air at room temperature unless specially stated.
Example one
The preparation method of the bismuth titanate nanosheet containing bismuth vacancies comprises the following specific steps:
0.24 g titanium dioxide, 0.93 g bismuth oxide, 3.51 g sodium chloride, 4.47 g potassium chloride were placed in a mortar, ground for 30min, then calcined at 800 ℃ for 2 h, followed by centrifugal washing with deionized water, and finally dried in a 60 ℃ vacuum oven for 12 h to give bismuth titanate nanoplatelets as a white powdery solid. 2.64 g choline chloride was dissolved in 2.11 mL ethylene glycol to form an ionic eutectic solvent at room temperature. Adding 1 g bismuth titanate nanosheets into the ionic eutectic solvent, reacting at 80 ℃ for 4 h, then centrifugally washing with deionized water for 3 times, and finally drying in a vacuum oven at 60 ℃ for 12 h to obtain the bismuth titanate nanosheets containing bismuth vacancies.
FIG. 1 is a scanning electron microscope image of bismuth titanate nanoplatelets containing bismuth vacancies, from which it can be seen that the bismuth titanate nanoplatelets containing bismuth vacancies have a layered structure, the thickness of the nanoplatelets is in the nanometer level, the size of the plane is in the micrometer level, and the specific surface area is large.
Example two
Bismuth titanate nanosheet/UiO-66-NH containing bismuth vacancies 2 The preparation of the heterojunction comprises the following specific steps:
dispersing 980 mg bismuth titanate nanosheets containing bismuth vacancies in 3 ml deionized water, then adding 116.6 mg zirconium chloride, 90.5 mg diaminoterephthalic acid and 2 ml acetic acid, reacting at 100 ℃ for 24 h, then washing with deionized water for 3 times, soaking and washing with methanol for 3 times, and finally drying in a vacuum oven at 60 ℃ for 12 h to obtain the final product bismuth titanate nanosheets-10/UiO-66-NH 2 A heterojunction.
FIG. 2 shows the bismuth titanate nanosheet-10/UiO-66-NH containing bismuth vacancies 2 Scanning electron micrographs and transmission electron micrographs of the heterojunction from which it is possible to see the small size of the octahedron UiO-66-NH 2 Uniformly growing on the surface of the bismuth titanate nano-sheet containing bismuth vacancies.
EXAMPLE III
Bismuth titanate nanosheets/UiO-66-NH containing bismuth vacancies at different molar ratios 2 The preparation method of the heterojunction comprises the following specific steps:
dispersing 490 mg bismuth titanate nano-sheets containing bismuth vacancies in 3 ml deionized water, then adding 116.6 mg zirconium chloride, 90.5 mg diaminoterephthalic acid and 2 ml acetic acid, reacting at 100 ℃ for 24 h, then washing with deionized water for 3 times, soaking and washing with methanol for 3 times, and finally drying in a vacuum oven at 60 ℃ for 12 h to obtain the final product bismuth titanate nano-sheet containing bismuth vacancies-5/UiO-66-NH 2 A heterojunction.
Example four
Bismuth titanate nanosheets/UiO-66-NH containing bismuth vacancies at different molar ratios 2 The preparation of the heterojunction comprises the following specific steps:
dispersing 1470 mg bismuth titanate nanosheets containing bismuth vacancies in 3 ml deionized water, then adding 116.6 mg zirconium chloride, 90.5 mg diaminoterephthalic acid and 2 ml acetic acid, reacting at 100 ℃ for 24 h, then washing with deionized water for 3 times, soaking and washing with methanol for 3 times, and finally drying in a vacuum oven at 60 ℃ for 12 h to obtain the final product bismuth titanate nanosheets-15/UiO-66-NH 2 A heterojunction.
Example Piezo-catalytic Oxidation experiment of PentaFormaldehyde gas
Diluting 37% formaldehyde solution into 75 mg/mL formaldehyde solution, placing 20 μ L formaldehyde solution in 5L gas generator, heating to volatilize formaldehyde gas to form formaldehyde with concentration of about 300 mg/m 3 The simulated gas of (2).
Bismuth titanate nanosheets/UiO-66-NH containing bismuth vacancies at room temperature 2 The heterojunction material or other catalysts are placed in simulated gas containing formaldehyde gas, the simulated gas is vibrated for a certain time by taking ultrasound as a mechanical source, and a change curve of the concentration of formaldehyde in the simulated gas along with the vibration time is measured so as to evaluate the effect of the composite material on the piezoelectric catalytic oxidation of the formaldehyde gas in the air under the action of mechanical force.
75 mg catalyst is placed in a 5L concentration of 300 mg/m 3 Ultrasonic (480W, 45 Hz), sampling 5 mL every 30min, injecting into color-developing agent, and allowingAnd detecting the absorbance of the sample at the wavelength of 630 nm by using an ultraviolet-visible spectrophotometer, and calculating the concentration of the obtained residual formaldehyde through a formaldehyde concentration-absorbance standard curve. Along with the progress of the piezoelectric catalysis, the residual concentration of the formaldehyde is gradually reduced, so that a specific piezoelectric catalytic oxidation curve of the formaldehyde is obtained.
The catalysts are bismuth titanate nano-sheets, bismuth titanate nano-sheets containing bismuth vacancies and bismuth titanate nano-sheets/UiO-66-NH containing bismuth vacancies with different molar ratios 2 . FIG. 3 is the piezoelectric catalytic oxidation curve of different catalysts for formaldehyde gas in simulated gas, and it can be seen that the bismuth titanate nanosheet-10/UiO-66-NH containing bismuth vacancies of the present invention 2 The efficiency of the heterojunction on the piezoelectric catalytic oxidation of formaldehyde gas in the simulated gas is highest, and the removal rate reaches 95.1% in 180 minutes; while the 180-minute removal rate of the bismuth titanate nanosheet alone is only 39.8%; illustrating the bismuth titanate nanoplatelets containing bismuth vacancies of the present invention-10/UiO-66-NH 2 The catalyst has excellent catalytic performance. In particular, 75 mg catalyst (example two) was placed in a 5L concentration of 200 mg/m 3 In the formaldehyde simulated gas, the formaldehyde can be completely removed in 150min, correspondingly, in the third embodiment, the formaldehyde can be completely removed in 180 min, the rest catalysts can not be completely removed in 180 min, and the residue is more than 15mg/m 3 。
EXAMPLE six bismuth titanate nanoplatelets containing bismuth vacancies-10/UiO-66-NH 2 Circulation experiment of heterojunction on piezoelectric catalytic oxidation of formaldehyde in air
In the fifth embodiment, the composite material recovered after being subjected to ultrasonic treatment for 180 min is washed by deionized water, is placed in a vacuum oven for drying, and is added again into newly prepared 5L with the concentration of 300 mg/m 3 The formaldehyde simulated gas of (2) was subjected to ultrasonic treatment (480W, 45 Hz), 5 mL was sampled every 30min, injected into a color developing agent, and the absorbance of the sample at a wavelength of 630 nm was measured using an ultraviolet-visible spectrophotometer and the concentration of the residual formaldehyde was calculated from a formaldehyde concentration-absorbance standard curve. The above steps were repeated 5 times, and the data were tested and recorded separately, the results of which are shown in fig. 4. It can be seen that the piezoelectric catalyst of the present invention maintains excellent piezoelectric catalytic performance throughout five repetitions. Therefore, the catalyst can be used repeatedly,has good stability.
Comparative example 1
The molten salt method of example one was replaced with a solvothermal method:
dissolving 12 g sodium hydroxide in 30 mL deionized water, and performing ultrasonic dispersion and dissolution to form a sodium hydroxide solution; adding 0.84 g tetrabutyl titanate and 2.79 g bismuth nitrate pentahydrate into a sodium hydroxide aqueous solution under stirring, continuously stirring 2 h, performing ultrasonic treatment for 30min, transferring to a 50ml stainless steel high-pressure reaction kettle lined with polytetrafluoroethylene, and heating at 180 ℃ for 20 hours; after the reaction, the sample was washed 3 times with deionized water and ethanol, and dried under vacuum at 60 ℃ for 12 h to obtain bismuth titanate nanospheres. 2.64 g choline chloride was dissolved in 2.11 mL ethylene glycol to form an ionic eutectic solvent at room temperature. Adding 1 g bismuth titanate nanospheres into an ionic eutectic solvent, reacting at 80 ℃ for 4 h, then centrifugally washing with deionized water for 3 times, and finally drying in a vacuum oven at 60 ℃ for 12 h to obtain bismuth titanate nanospheres containing bismuth vacancies. Then, bismuth titanate nanospheres containing bismuth vacancies-10/UiO-66-NH were prepared according to example two 2 A heterojunction.
Referring to the fifth example, the room temperature formaldehyde gas piezoelectric catalytic oxidation experiment is performed, and the result is shown in fig. 5, the catalyst obtained by the solvothermal reaction has poor piezoelectricity, the maximum removal rate is 64.1%, and the time is difficult to increase.
Comparative example No. two
Taking the bismuth titanate nanoplatelets of example one, referring to the method of example two, bismuth titanate nanoplatelets/UiO-66-NH were obtained 2 A heterojunction. The room temperature formaldehyde gas piezoelectric catalytic oxidation experiment is carried out according to the fifth embodiment, and the result is shown in fig. 6, and the bismuth vacancy obviously improves the catalytic performance.
Comparative example No. three
Taking the bismuth titanate nanosheet of the first embodiment, placing the bismuth titanate nanosheet in a tubular furnace, annealing at 260 ℃ for 15 minutes under vacuum to obtain the oxygen vacancy-containing bismuth titanate nanosheet, performing a room-temperature formaldehyde gas piezoelectric catalytic oxidation experiment according to the fifth embodiment, wherein the oxygen vacancy-containing bismuth titanate nanosheet is inferior in piezoelectric catalytic performance to the bismuth titanate nanosheet containing the bismuth vacancy, and the formaldehyde removal rate at 180 minutes is 46.9%.
The invention takes bismuth titanate nano-sheet containing bismuth vacancy as a substrate and hydrothermally grows UiO-66-NH 2 Bismuth titanate nanosheet/UiO-66-NH containing bismuth vacancies constructed by nanoparticles 2 A heterojunction. The electronic structure is effectively modulated, the charge transmission property is improved, and the charge diffusion coefficient is obviously improved, so that the charge transmission efficiency is improved; having an ultra-high specific surface area and permanent porosity, with-NH 2 The introduction of (A) increases the adsorption performance of the material on gaseous formaldehyde, and in addition, uiO-66-NH 2 The skeleton structure can bear 1MPa of mechanical pressure and has good chemical stability. Bismuth titanate nano-sheet/UiO-66-NH containing bismuth vacancy prepared by the invention 2 The heterojunction realizes the high-efficiency piezoelectric catalytic oxidation of formaldehyde gas through the synergistic effect of adsorption catalysis, which is the first example of pure piezoelectric catalysis for removing formaldehyde.
Claims (10)
1. Bismuth titanate nanosheet/UiO-66-NH containing bismuth vacancies 2 The preparation method of the heterojunction is characterized by comprising the following steps: (1) Mixing titanium dioxide, bismuth oxide and inorganic salt, calcining to obtain a bismuth titanate nano sheet, and then immersing the bismuth titanate nano sheet into an ionic eutectic solvent to obtain a bismuth titanate nano sheet containing bismuth vacancies; (2) Carrying out hydrothermal reaction on a mixture of bismuth titanate nanosheets containing bismuth vacancies, diaminoterephthalic acid, zirconium chloride and acetic acid to obtain bismuth titanate nanosheets/UiO-66-NH containing bismuth vacancies 2 A heterojunction.
2. The bismuth titanate nanoplatelets/UiO-66-NH containing bismuth vacancies of claim 1 2 The preparation method of the heterojunction is characterized by comprising the following steps: (1) Mixing and grinding titanium dioxide, bismuth oxide and inorganic salt, then calcining to prepare a bismuth titanate nanosheet, and then immersing the bismuth titanate nanosheet in an ionic eutectic solvent consisting of a hydrogen bond donor and a hydrogen bond acceptor to form a bismuth titanate nanosheet containing bismuth vacancies; (2) Adding diamino terephthalic acid, zirconium chloride and acetic acid into bismuth titanate nanosheet solution containing bismuth vacancies, and carrying out hydrothermal reaction to prepare bismuth titanate nanosheet/UiO-66-NH containing bismuth vacancies 2 A heterojunction material.
3. The bismuth titanate nanoplatelets/UiO-66-NH containing bismuth vacancies according to claim 2 2 The preparation method of the heterojunction is characterized in that in the step (1), the hydrogen bond donor is ethylene glycol, and the hydrogen bond acceptor is choline chloride.
4. The bismuth titanate nanoplatelets/UiO-66-NH containing bismuth vacancies of claim 1 2 The preparation method of the heterojunction is characterized in that in the step (1), the inorganic salt is sodium chloride or potassium chloride; the molar ratio of titanium dioxide to bismuth oxide is 3: 2, and the molar ratio of bismuth titanate to sodium chloride to potassium chloride is 1: 40-90; the calcining temperature is 500-1000 deg.C, and the calcining time is 1-5 hr.
5. The bismuth titanate nanoplatelets/UiO-66-NH containing bismuth vacancies of claim 1 2 The preparation method of the heterojunction is characterized in that in the step (1), a hydrogen bond donor and a hydrogen bond acceptor are mixed to form an ionic eutectic solvent, the bismuth titanate nanosheet is immersed in the ionic eutectic solvent and reacts at 70-90 ℃ for 2 h-10 h, and the bismuth titanate nanosheet containing bismuth vacancies is obtained.
6. The bismuth titanate nanoplatelets/UiO-66-NH containing bismuth vacancies of claim 1 2 The preparation method of the heterojunction is characterized in that in the step (2), the mass ratio of the bismuth titanate nano-sheet containing bismuth vacancy, the diamino terephthalic acid and the zirconium chloride is (400-1500) to (100-150) to (80-100); the hydrothermal reaction is carried out for 20 to 30 hours at a temperature of between 80 and 120 ℃.
7. The bismuth titanate nanoplatelets/UiO-66-NH containing bismuth vacancies of claim 1 2 Bismuth titanate nanosheet/UiO-66-NH containing bismuth vacancy prepared by preparation method of heterojunction 2 A heterojunction.
8. A process for the catalytic oxidation of formaldehyde comprising the steps of: subjecting the bismuth vacancy-containing titanium of claim 7Bismuth acid nano-sheet/UiO-66-NH 2 The heterojunction is placed in an environment containing formaldehyde, and catalytic oxidation of the formaldehyde is realized under the ultrasonic condition.
9. The bismuth titanate nanoplatelets/UiO-66-NH containing bismuth vacancies of claim 7 2 Use of a heterojunction for the treatment of contaminants.
10. The bismuth titanate nanoplatelets/UiO-66-NH containing bismuth vacancies of claim 7 2 Application of the heterojunction in removing formaldehyde by piezoelectric catalysis.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105597728A (en) * | 2016-02-25 | 2016-05-25 | 电子科技大学 | Titanium dioxide/bismuth titanate ultrasonic enhanced photocatalyst and preparation method thereof |
| CN107008473A (en) * | 2017-05-18 | 2017-08-04 | 江苏大学 | A kind of three-dimensional structure bismuth titanates nanometer sheet/perite nanometer piece composite photo-catalyst and preparation method thereof |
| CN107586473A (en) * | 2017-10-24 | 2018-01-16 | 江苏华夏制漆科技有限公司 | A kind of coating using bismuth titanates as photochemical catalyst and preparation method thereof |
| CN110841668A (en) * | 2019-11-08 | 2020-02-28 | 苏州大学 | Bismuth oxyiodide/zinc oxide composite material, preparation method thereof and application thereof in piezoelectric-photocatalytic removal of organic pollutants |
| CN112619675A (en) * | 2020-12-09 | 2021-04-09 | 中山大学 | Preparation method of composite piezoelectric catalyst and method for preparing hydrogen peroxide |
| CN114733573A (en) * | 2022-03-05 | 2022-07-12 | 重庆工商大学 | Bismuth titanate @ NH2Preparation and application of-MIL-125 photocatalyst |
| CN114939423A (en) * | 2022-06-24 | 2022-08-26 | 武汉科技大学 | Bi 4 Ti 3 O 12 /Bi 2 S 3 Piezoelectric photocatalyst and preparation method thereof |
| CN115121289A (en) * | 2022-07-06 | 2022-09-30 | 苏州大学 | Barium titanate nano-particle composite covalent organic framework heterojunction and preparation method thereof |
-
2022
- 2022-10-09 CN CN202211225056.8A patent/CN115870010A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105597728A (en) * | 2016-02-25 | 2016-05-25 | 电子科技大学 | Titanium dioxide/bismuth titanate ultrasonic enhanced photocatalyst and preparation method thereof |
| CN107008473A (en) * | 2017-05-18 | 2017-08-04 | 江苏大学 | A kind of three-dimensional structure bismuth titanates nanometer sheet/perite nanometer piece composite photo-catalyst and preparation method thereof |
| CN107586473A (en) * | 2017-10-24 | 2018-01-16 | 江苏华夏制漆科技有限公司 | A kind of coating using bismuth titanates as photochemical catalyst and preparation method thereof |
| CN110841668A (en) * | 2019-11-08 | 2020-02-28 | 苏州大学 | Bismuth oxyiodide/zinc oxide composite material, preparation method thereof and application thereof in piezoelectric-photocatalytic removal of organic pollutants |
| CN112619675A (en) * | 2020-12-09 | 2021-04-09 | 中山大学 | Preparation method of composite piezoelectric catalyst and method for preparing hydrogen peroxide |
| CN114733573A (en) * | 2022-03-05 | 2022-07-12 | 重庆工商大学 | Bismuth titanate @ NH2Preparation and application of-MIL-125 photocatalyst |
| CN114939423A (en) * | 2022-06-24 | 2022-08-26 | 武汉科技大学 | Bi 4 Ti 3 O 12 /Bi 2 S 3 Piezoelectric photocatalyst and preparation method thereof |
| CN115121289A (en) * | 2022-07-06 | 2022-09-30 | 苏州大学 | Barium titanate nano-particle composite covalent organic framework heterojunction and preparation method thereof |
Non-Patent Citations (2)
| Title |
|---|
| YUAN LU ET AL.: "Boosting Charge Transport in BiVO4 Photoanode for Solar Water Oxidation", 《ADV. MATER.》, no. 34, pages 1 - 8 * |
| 方宇: "铋基半导体/MOFs复合材料的制备及其光催化性能研究", 《中国优秀硕士学位论文全文数据库工程科技Ⅰ辑》, no. 1, pages 014 - 1135 * |
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