CN101612565B

CN101612565B - Bi2WO6 nano-fiber cloth and preparation method and application thereof

Info

Publication number: CN101612565B
Application number: CN2009100551732A
Authority: CN
Inventors: 王文中; 尚萌
Original assignee: Shanghai Institute of Ceramics of CAS
Current assignee: Shanghai Institute of Ceramics of CAS
Priority date: 2009-07-21
Filing date: 2009-07-21
Publication date: 2011-08-31
Anticipated expiration: 2029-07-21
Also published as: CN101612565A

Abstract

The invention relates a Bi2WO6 nano-fiber cloth and a preparation method and an application thereof. The nano-fiber cloth is characterized in that the nano-fiber is prepared from Bi2WO6 nano-fiber with a length of hundreds of microns and a diameter of 30-400nm by electrostatic spinning; wherein, a defined amount of reactants are mixed and stirred according to a stoichiometry ratio, then proper tackifier is added to obtain Bi2WO6 precursor with proper viscosity and charge quantity, and finally Bi2WO6 nano-fiber cloth with controllable size, crystal type and morphology can be obtained through the control of the proportioning of each material in the precursor solution and the conditions of the electrostatic spinning. The Bi2WO6 nano-fiber cloth prepared by the electrostatic spinning used as photocatalyst has high specific area and crystallinity so that the visible light activity of the cloth is high, a certain kind of organic pollutants can be degraded in short time, and meanwhile, the catalyst can be recycled and reused very conveniently so that the problem of practical application of photocatalyst is solved.

Description

A kind of Bi 2WO 6Nano-fiber cloth, preparation method and application

Technical field

The present invention relates to visible light responsive photocatalyst, preparation method and application, particularly Bi ₂WO ₆Nano-fiber cloth, preparation method, and utilize it under illumination, to decompose harmful chemical.Belong to Bi ₂WO ₆Material and application.

Background technology

Because environmental pollution and the energy crisis that increase the weight of day by day in the whole world, the research of conductor photocatalysis and application have caused people's extensive concern.The key problem of photocatalysis technology is the appropriate light catalyst design, exploitation and development, and the research of particularly visible light-responded high-performance optical catalysis material becomes the task of top priority.1999, Kudo etc. (Chem.Lett.1999,83,1103.) reported Bi ₂WO ₆As a kind of novel photocatalysis agent with visible light activity, employing be traditional high temperature solid-phase sintering method.After this, people adopt methods such as coprecipitation, hydro-thermal method and the organic sedimentation of metal to prepare Bi again ₂WO ₆Be to promote photocatalysis efficiency, reduce catalysis material size, to increase surface area etc. be valid approach.But after particle reduced, if adopt the heterogeneous catalytic reaction system that suspends, what bring was the difficult problem that granule separates from system, and it is difficult to reclaim.Therefore the load technology of photochemical catalyst becomes the direction that people make great efforts.Yet load rear catalyst surface area descends, and catalytic performance also decreases.So, seek not only can to keep high activity but also can realize that rapidly and efficiently reclaiming of catalysis material become the march toward key of practical application of photocatalysis technology.

Summary of the invention

The object of the present invention is to provide a kind of Bi ₂WO ₆Nano-fiber cloth, preparation method and application, the Bi that is provided ₂WO ₆But characteristics such as the preparation method of nano-fiber cloth stability height, the low magnanimity preparation of cost of manufacture, environmental friendliness, synthetic Bi ₂WO ₆Fiber cloth is active and Bi that easily reclaim as the high visible that is evenly distributed ₂WO ₆Photochemical catalyst.

The Bi of the present invention's preparation ₂WO ₆The feature of nano-fiber cloth is:

1. described nano-fiber cloth is to reach microns up to a hundred by length, and diameter is the Bi of 30-400nm ₂WO ₆The nanofiber method of electrostatic spinning forms;

2. described nano-fiber cloth has self-supporting, fiber distribution homogeneous;

3. described Bi ₂WO ₆Nanofiber is by the littler nanometer Bi of diameter ₂WO ₆Particle is formed.

The concrete steps of preparation are:

(a) preparation of presoma

Press Bi ₂WO ₆Stoichiometric proportion mixes a certain amount of reactant.Reactant is nitrate, the chloride that contains bismuth ion, oxalates, and the sodium salt of citrate etc. and tungstenic or ammonium salt etc. are dissolved in the solvent, and adding concentration is 20～80gL ^-1Tackifier obtain the predecessor of different viscosities.Tackifier are polyvinyl alcohol (PVA), polyoxygenated ethane (PEO), polyvinylpyrrolidone (PVP) and polyacrylonitrile (PAN) etc.; Described solvent is water, ethanol, acetone, oxolane, N, dinethylformamide with and composite cosolvent.

(b) electrostatic spinning prepares nano-fiber cloth

At room temperature, with above-mentioned presoma at voltage 5～30KV, operating distance 5～25cm, spinning speed is 0.5～6mLh ^-1Condition under spinning 0.5～5 hour; The nano-fiber cloth that obtains at 350～700 ℃ of sintering.By the control of each material proportioning and spinning condition in the presoma, obtain the Bi that the controlled high activity of size, crystal formation and pattern easily reclaims ₂WO ₆Nano-fiber cloth.

The present invention and the Bi that adopts the additive method preparation ₂WO ₆Photochemical catalyst has been compared following advantage:

(a) preparation process is at room temperature opened wide in the system and is carried out, and does not need to carry out high temperature high pressure process, just can obtain to have highly active Bi ₂WO ₆Nano-fiber cloth.

(b) Zhi Bei Bi ₂WO ₆Nano-fiber cloth has the self-supporting performance, and fibre length can reach microns up to a hundred, and the diameter of fiber can be regulated and control arbitrarily by 30～400nm, and distributes than homogeneous.By forming large-area fiber cloth on the electrospinning process macroscopic view.Described Bi ₂WO ₆Nanofiber is actual to be made up of the littler nano particle of size.

(c) preparation technology is simple, and the cycle is short, is fit to produce in batches;

(d) prepared Bi ₂WO ₆The nano-fiber cloth photochemical catalyst not only can be implemented under the radiation of visible light and excites, and also has high photolytic activity, the pollutant of certain kind of can degrading at short notice.Photocatalytic Activity for Degradation efficient is than the powder and the N-TiO of other method preparation ₂Exceed tens times.At environmental improvement (empty G﹠W), photochemical catalyzing, aspect such as antibiotic good prospects for application is arranged.Prepared Bi ₂WO ₆Nano-fiber cloth produces CO in the visible light degrade acetaldehyde of wavelength＞420nm ₂Concentration is 80-150ppm.(seeing embodiment for details)

(e) prepared Bi ₂WO ₆Nano-fiber cloth is recovery and reuse easily, have solved the difficult problem of photochemical catalyst practical application.

Description of drawings

Fig. 1 is the Bi of method of electrostatic spinning preparation among the embodiment 1 ₂WO ₆Nano-fiber cloth XRD diffracting spectrum

Fig. 2-1 prepares Bi for method of electrostatic spinning ₂WO ₆The stereoscan photograph of nano-fiber cloth

Fig. 2-2 is single Bi ₂WO ₆The stereoscan photograph of fiber

Fig. 3 prepares Bi for method of electrostatic spinning ₂WO ₆Diffuse reflectance spectra

Fig. 4 prepares Bi for method of electrostatic spinning ₂WO ₆Fiber cloth, the Bi of Hydrothermal Preparation ₂WO ₆Particle, the Bi of solid phase method preparation ₂WO ₆And the TiO of nitrogen doping ₂To acetaldehyde degradation rate correlation curve.

The specific embodiment

Embodiment 1

Bi ₂WO ₆Use Bi (NO ₃) ₃5H ₂O and Na ₂WO ₄2H ₂O (analyzing pure) is synthetic for raw material, according to stoichiometric proportion, takes by weighing 0.97g Bi (NO ₃) ₃5H ₂O (analyzing pure) is dissolved in the 20mL ethanol, adds 0.329g Na then ₂WO ₄2H ₂O (analyzing pure), 1g PVA stir and form the white suspension precursor liquid.Then precursor liquid is packed into and carry out electrostatic spinning in the syringe, through comparative experiments, choosing operating distance is 10cm, and operating voltage is 20KV.After reaction finishes, with the nano-fiber cloth that obtains at 500 ℃ of sintering.As Fig. 1, thank through XRD constituent analysis and debye and to rein in formula and calculate, obtained the nanofiber Bi that 100nm left and right sides particle is formed ₂WO ₆Fig. 2 is the exemplary scanning electromicroscopic photograph of spinning sample, and as can be seen from the figure, the nanofiber diameter that has self-supporting is about 150nm, and it is actual to be nanometer Bi by the about 100nm of size ₂WO ₆Particle is formed.

Fig. 3 is product ultraviolet/visible diffuse reflectance spectra, as can be seen from the figure, and the Bi that present embodiment is prepared ₂WO ₆Nano-fiber cloth all has photoresponse from ultraviolet region up to the visible region as photochemical catalyst, and the estimation band gap is 2.7eV.

For research institute prepares the photocatalysis performance of sample, the design visible light is the experiment of degraded aldehydes gas down.Utilize the acetaldehyde photocatalytic degradation to be CO ₂Character, by gas chromatographic measurement CO ₂Output is judged the variation of aldehydes gas, and then draws degradation rate.In order to compare, with the Bi of (0.1g) method of electrostatic spinning preparation of equivalent ₂WO ₆The particle of nano-fiber cloth, Hydrothermal Preparation, the TiO that the powder of solid phase reaction preparation and nitrogen mix ₂Powder (N-TiO ₂), joining respectively in the aldehydes gas that 600mL concentration is 100ppm, adsorption equilibrium 30 minutes places the 500W xenon lamp of the optical filter filtration of wavelength＞420nm to shine down then.Through 300 minutes Photocatalytic Activity for Degradation, the Bi of method of electrostatic spinning preparation ₂WO ₆The nano-fiber cloth degradation effect is obvious, and other three kinds of photocatalyst for degrading DeGrains.As a comparison, provided the Bi that the reaction of equal in quality electrostatic spinning, hydro-thermal reaction, solid phase reaction prepare among Fig. 4 ₂WO ₆And N-TiO ₂Degraded situation under the same conditions.Through gas chromatographic measurement and calculating: the Bi of method of electrostatic spinning preparation ₂WO ₆Nano-fiber cloth produces CO ₂Concentration is 145ppm, and efficient is N-TiO under the similarity condition ₂Tens times.And the Bi of use solid reaction process and Hydrothermal Preparation ₂WO ₆Photocatalysis efficiency not high yet, proved that method of electrostatic spinning prepares nano-fiber cloth, as the high visible light photocatalysis active of photochemical catalyst.

Embodiment 2

Bi ₂WO ₆Use bismuth citrate and Na ₂WO ₄2H ₂O (analyzing pure) is synthetic for raw material, according to stoichiometric proportion, takes by weighing 0.796g bismuth citrate (analyzing pure) and is dissolved in the 20mL ethanol, adds 0.329gNa then ₂WO ₄2H ₂O (analyzing pure), 0.5g PEO stir and form the white suspension precursor liquid.Then precursor liquid is packed into and carry out electrostatic spinning in the syringe, through comparative experiments, choosing operating distance is 20cm, and operating voltage is 25KV.After reaction finishes, with the nano-fiber cloth that obtains at 400 ℃ of sintering.Product is defined as Bi through the XRD constituent analysis ₂WO ₆, being about 200nm through the electron microscopic observation particle size, the visible light degrade acetaldehyde of wavelength＞420nm is produced CO ₂Experimental result is more lower slightly than embodiment 1, CO ₂Concentration is 117ppm.

Embodiment 3

Bi ₂WO ₆Use bismuth oxalate and H ₄₀N ₁₀O ₄₁W ₁₂XH ₂O (analyzing pure) is synthetic for raw material, according to stoichiometric proportion, takes by weighing 1.617g bismuth oxalate (analyzing pure) and is dissolved in the 20mL ethanol, adds 0.329gNa then ₂WO ₄2H ₂O (analyzing pure), 1g PVP stir and form the white suspension precursor liquid.Then precursor liquid is packed into and carry out electrostatic spinning in the syringe, through comparative experiments, choosing operating distance is 25cm, and operating voltage is 10KV.After reaction finishes, with the nano-fiber cloth that obtains at 550 ℃ of sintering.Product is defined as Bi through the XRD constituent analysis ₂WO ₆, being about 300nm through the electron microscopic observation particle size, the visible light degrade acetaldehyde of wavelength＞420nm is produced CO ₂Experimental result is lower than embodiment 1, CO ₂Concentration is 95ppm.

Embodiment 4

Bi ₂WO ₆Use bismuth acetate and Na ₂WO ₄2H ₂O (analyzing pure) is synthetic for raw material, according to stoichiometric proportion, takes by weighing 0.772g bismuth acetate (analyzing pure) and is dissolved in the 15mL ethanol, adds 0.329gNa then ₂WO ₄2H ₂O (analyzing pure), 1g PVA stir and form the white suspension precursor liquid.Then precursor liquid is packed into and carry out electrostatic spinning in the syringe, through comparative experiments, choosing operating distance is 15cm, and operating voltage is 15KV.After reaction finishes, with the nano-fiber cloth that obtains at 600 ℃ of sintering.Product is defined as Bi through the XRD constituent analysis ₂WO ₆, being about 350nm through the electron microscopic observation particle size, the visible light degrade acetaldehyde of wavelength＞420nm is produced CO ₂Experimental result is lower than embodiment 1, CO ₂Concentration is 87ppm.

Claims

1. Bi ₂WO ₆Nano-fiber cloth is characterized in that described nano-fiber cloth is to reach microns up to a hundred by length, and diameter is the Bi of 30-400nm ₂WO ₆The nanofiber method of electrostatic spinning forms.

2. by the described Bi of claim 1 ₂WO ₆Nano-fiber cloth is characterized in that described nano-fiber cloth has self-supporting, fiber distribution homogeneous.

3. by the described Bi of claim 1 ₂WO ₆Nano-fiber cloth is characterized in that described Bi ₂WO ₆Nanofiber is by the littler nanometer Bi of diameter ₂WO ₆Particle is formed.

4. prepare Bi as claimed in claim 1 ₂WO ₆The method of nano-fiber cloth is characterized in that with salt that contains bismuth ion and sodium salt or the ammonium salt that contains tungsten ion be raw material, presses Bi ₂WO ₆Stoichiometric proportion is made presoma, under the effect of high-voltage electrostatic spinning, obtains Bi then ₂WO ₆Nano-fiber cloth, at last sintering forms under 700 ℃ the condition being less than or equal to.

5. Bi according to claim 4 ₂W0 ₆The preparation method of nano-fiber cloth is characterized in that step is:

(a) preparation of presoma

Press Bi ₂WO ₆Stoichiometric proportion mixes a certain amount of reactants dissolved in solvent, reactant is nitrate, oxalates, chloride or citrate and sodium salt that contains tungsten ion or the ammonium salt that contains bismuth ion, and adding concentration is 20～80gL ^-1Tackifier, the presoma that form to suspend; Described tackifier are polyvinyl alcohol, polyoxygenated ethane, polyvinylpyrrolidone or polyacrylonitrile;

(b) preparation of nano-fiber cloth under the electrostatic spinning condition

At room temperature, the presoma of step a preparation is packed into carry out electrostatic spinning in the syringe; At voltage 5～30KV, operating distance 5～25cm, spinning speed is 0.5～6mLh ^-1Condition under spinning make Bi ₂WO ₆Nanofiber, with the nano-fiber cloth made at 350～700 ℃ of sintering.

6. by the described Bi of claim 5 ₂WO ₆The preparation method of nano-fiber cloth is characterized in that described solvent is water, ethanol, acetone, oxolane, N, dinethylformamide, with and composite cosolvent.

7. by the described Bi of claim 5 ₂WO ₆The preparation method of nano-fiber cloth, the time that it is characterized in that electrostatic spinning is 0.5-5 hour.

8. by the described Bi of claim 1 ₂WO ₆The application of nano-fiber cloth has high visible light catalysis activity in it is characterized in that being implemented in from the ultra-violet (UV) band to the visible region as photochemical catalyst.

9. by the described Bi of claim 8 ₂WO ₆The application of nano-fiber cloth is characterized in that prepared Bi ₂WO ₆Nano-fiber cloth produces CO in the visible light degrade acetaldehyde of wavelength＞420nm ₂Concentration be 80-150ppm.