A kind of preparation method of single-phase bismuth titanate nano-material and application
Technical field
The present invention relates to nano material and Environmental Science and Engineering field, be specifically related to a kind of preparation method and application that under sunshine, has the active single-phase bismuth titanate nano-material of photocatalysis degradation organic contaminant.
Background technology
21 century the energy and one of the important goal of environmental area be exactly through utilizing the friendly type functional material of regenerative resource and novel environmental to administer or repair ecological environment, and on to greatest extent, improve the service efficiency of novel environmental close friend type functional material.The conductor photocatalysis technology will have been given play to important function undoubtedly in this field, at present, the conductor photocatalysis technology demonstrates wide application prospect in fields such as environmental protection, light degradation hydrogen manufacturing and photocatalysis sterilizations, wherein TiO
2Caused scientific worker's extensive interest as a kind of ripe semiconductor light-catalyst in the application aspect energy development and the environmental improvement, yet its lower photocatalytic activity and low sunshine utilization rate (less than 5%) have limited the range of application of this material.Therefore search out the dream that the new function material that under sunshine, has high photocatalytic activity becomes numerous scientific workers.
In recent years, novel bismuth titanates material has caused material scholar and physicist's extensive concern with its excellent physical property and chemism.The bismuth titanates material belongs to the system of a complicacy, comprises Bi in this individual system
2Ti
2O
7, Bi
2Ti
4O
11, Bi
4Ti
3O
12, Bi
12TiO
20And Bi
20TiO
32Etc. different phases, they have a wide range of applications at aspects such as ferroelectric material, dielectric material, piezoelectric, sensor, capacitor, light refraction material and catalysis materials.Proportion of raw materials and different reaction conditions in the building-up process are depended in the generation of these different phase bismuth titanates, therefore in prior synthesizing method, are difficult to prepare the bismuth titanates material of single crystalline phase.
Bi
20TiO
32Be bismuth titanates series material a kind of with photocatalytic activity, it can satisfy and under sunshine, still has this requirement of high photocatalysis performance, and this material itself is nontoxic, meets the requirement of the friendly type catalysis material of novel environmental.But Bi under general condition,
20TiO
32Be in a kind of metastable state, it only at titanium bismuth mixed oxide to Bi
2Ti
2O
7Occur in the process that crystal formation transforms, through consulting Bi
2O
3-TiO
2The phasor of system can know, under normal conditions Bi
20TiO
32Be in metastable state, it is lower than in temperature under 400 ℃ the condition and can not forms.Having synthesized of having reported at present contains Bi
20TiO
32The document of catalysis material mainly contains: YunHou et al.Bi
20TiO
32Nanocones prepared from Bi-Ti-O mixture by metalorganicdecomposition method.Journal of Crystal Growth, 2002,240:489-494 synthesizes with the Organometallic Chemistry method in this article and contains Bi
20TiO
32The titanium bismuth mixed oxide of crystalline phase; Xu Xiaohong etc. the Photocatalytic Performance Study of bismuth titanates based compound. chemical journal, 2005,63 (1): 5-10, this article have compared the degradation capability of the bismuth titanates of different crystal forms structure; WenFeng Yao et al.Photocatalytic property ofZn-modified bismuth titanate.Journal of Molecular Catalysis A:Chemical, 2003,198:343-348 describes the similar Bi of consisting of in this article
20TiO
32The bismuth titanates material list revealed higher photocatalytic activity, but it is not furtherd investigate; Chinese patent CN101574653 " a kind of have visible light-responded bismuth titanate photocatalytic material and preparation method thereof " discloses a kind of quench hot method and has prepared pure phase bismuth titanates Bi
20TiO
32The method of material.Through the introducing us and find that existing synthetic bismuth titanate photocatalyst is mainly non-pure phase of above-mentioned prior art, and the synthesis temperature in the existing method is higher, because Bi
20TiO
32Synthesis condition harshness and metastability thereof except the quench hot method, also do not have other under temperate condition, to synthesize and have the active single-phase Bi of higher sunlight catalytic at present
20TiO
32The report of nano-photocatalyst material.
Summary of the invention
The objective of the invention is to overcome deficiency of the prior art, a kind of single-phase bismuth titanate Bi is provided
20TiO
32Preparation of nanomaterials.This preparation method has that cost is low, reaction condition is gentle, the instrument and equipment requirement is low and be easy to plurality of advantages such as large-scale production, so wide industrial applications prospect is arranged.
Another object of the present invention is to provide a kind of single-phase bismuth titanate Bi
20TiO
32The application of nano material aspect the common organic pollution of photocatalytic degradation; This nano material is high as photochemical catalyst degradation efficiency to organic pollution under sunshine; And the regenerability of catalyst is good, so the inventive method prepared nano material has wide application prospect in the photocatalysis degradation organic contaminant field.
A kind of single-phase bismuth titanate Bi
20TiO
32Preparation of nanomaterials, its technical scheme is: prepare presoma with supercritical methanol technology earlier, form single-phase Bi through the roasting crystallization again
20TiO
32Nano material.
The concrete operations step is following:
1. the preparation of raw material: soluble bismuth salt is joined in the small-molecular weight carboxylic acid, and making bismuth/carboxylic acid mol ratio is 1: 40-70 constantly is stirred to bismuth salt and dissolves fully; In solution, dropwise add titanate esters again; Making titanium/bismuth mol ratio is 1: 8-13, continue to stir to clarify the back to wherein adding the bigger alcohol of molecular weight as structure directing agent, and making bismuth/pure mol ratio is 1: 3-4.5; Can be after stirring to wherein adding urea; Making bismuth/urea mol ratio is 1: 0-5, stir to clarify transparent, solution I;
2. supercritical reaction: with step 1. the gained solution I be injected in the less alcoholic solvent of molecular weight; Solvent volume is the every gram soluble bismuth salt of a 25-45mL raw material; Be transferred to after mixing in the autoclave, feed 1012bar nitrogen, under its protection, be heated to 200-250 ℃ and keep 2-6h; Make bismuth salt complete hydrolysis or alcoholysis, open the venting valve then and discharge the Bi that solvent obtains drying
20TiO
32The presoma of nano material;
3. crystallization is shaped: the presoma that 2. step is made is successively with ethanol and deionized water washing, dry after at 280-500 ℃ of following roasting crystallization 2-8h, be cooled to room temperature after taking-up promptly get single-phase Bi
20TiO
32Nano material.
Soluble bismuth salt is bismuth nitrate, bismuth chloride or bismuth sulfate etc. in the above step; The small-molecular weight carboxylic acid is formic acid, acetate or propionic acid etc.; Titanate esters is butyl titanate or isopropyl titanate etc.; The alcohol that molecular weight is bigger is the tert-butyl alcohol, phenmethylol, benzyl carbinol or p-nitrophenyl methyl alcohol etc., and the less alcohol of molecular weight is methyl alcohol, ethanol or propyl alcohol etc.
Before crystallization process, be primary solvent in the inventive method with the small-molecular weight carboxylic acid; It can make the hydrolytic process of titanate esters and bismuth salt slow down and inhibition each other; Make resulting solution-stabilized and clarification, the urea that is added can be regulated the pattern of product and then influence its photocatalysis performance.
The Bi that the inventive method makes
20TiO
32Nano material has unique laminated structure with holes, uses the visible chip size of transmission electron microscope observation to be 20-100nm, and the aperture is 8-10nm (seeing Fig. 1-5) in the sheet, and its crystal phase structure is the Bi of single-phase tetragonal crystal system
20TiO
32(see figure 6).
Simultaneously through analyzing prepared Bi
20TiO
32The ultraviolet-visible diffuse reflection collection of illustrative plates (see figure 7) of nano material can know that this nano material all has stronger absorption in ultraviolet and visible region, shows that this catalyst has potential using value in fields such as utilizing sunlight catalytic degradable organic pollutant, catalysis sterilization, hydrogen production by water decomposition.
The present invention adopts the method for xenon lamp irradiation simulated solar spectrum, has investigated the prepared Bi of the present invention
20TiO
32The performance of the organic pollution that the nano material photocatalytic degradation is several frequently seen, result show, Bi
20TiO
32Nano material is fast for the degradation speed of common organic pollution, and degradation rate is high, and Bi
20TiO
32The regenerability of nano-photocatalyst is good.
The inventive method mainly contains following advantage:
1, raw material and equipment cost are low, and technology is simple, and reaction condition is gentle and be easy to control, is fit to large-scale industrialization production;
2, the inventive method gained Bi
20TiO
32Nano material has unique laminated structure with holes, and chip size is 20-100nm, and the aperture is 8-10nm in the sheet, and its crystal phase structure is the Bi of single-phase tetragonal crystal system
20TiO
32
3, the inventive method gained Bi
20TiO
32It is active that nano material has very high sunlight catalytic, need not other auxiliary agents, and organic dyestuff, phenols and other toxic and harmful substances that can not degrade in next step degradation biological method of sunshine have favorable industrial application prospect;
4, the inventive method gained Bi
20TiO
32Nano material is as photochemical catalyst, and its regenerability is good, is a kind of wide spectrum Multifucntional nano material.
Description of drawings
The Bi that Fig. 1: embodiment 1 is prepared
20TiO
32The transmission electron microscope image of nano material;
The Bi that Fig. 2: embodiment 2 is prepared
20TiO
32The transmission electron microscope image of nano material;
The Bi that Fig. 3: embodiment 4 is prepared
20TiO
32The transmission electron microscope image of nano material;
The Bi that Fig. 4: embodiment 5 is prepared
20TiO
32The transmission electron microscope image of nano material;
The Bi that Fig. 5: embodiment 6 is prepared
20TiO
32The transmission electron microscope image of nano material;
The Bi that Fig. 6: embodiment 1 is prepared
20TiO
32The XRD figure spectrum of nano material;
The Bi that Fig. 7: embodiment 1 is prepared
20TiO
32The UV, visible light solid diffuse reflection collection of illustrative plates of nano material;
Bi among Fig. 8: the embodiment 7
20TiO
32The ultraviolet-visible collection of illustrative plates of nano material photocatalytic degradation reactive brilliant red X3B;
Bi among Fig. 9: the embodiment 8
20TiO
32The ultraviolet-visible collection of illustrative plates of nano material photocatalytic degradation rhodamine B;
Bi among Figure 10: the embodiment 11
20TiO
32The ultraviolet-visible collection of illustrative plates of nano material photocatalytic degradation reactive brilliant red X3B.
The specific embodiment
Further set forth the present invention below in conjunction with specific embodiment.Should be appreciated that these embodiment only to be used to the present invention is described and do not limit the scope of requirement of the present invention protection.
Embodiment 1:
Take by weighing 8.0g bismuth nitrate (Bi (NO
3)
35H
2O) join in the acetate, making bismuth/carboxylic acid mol ratio is 1: 55, after constantly being stirred to bismuth nitrate and dissolving fully again to wherein dropwise adding butyl titanate; Making titanium/bismuth mol ratio is 1: 10; Continue to stir after the clarified solution to injecting structure directed agents phenmethylol wherein, making bismuth/pure mol ratio is 1: 3, in above-mentioned solution, adds urea at last; Making bismuth/urea mol ratio is 1: 1.5, is stirred to the solution clear then.Prepared solution is injected in the 220mL alcohol solvent, mixes the back and move in the autoclave, under the 12bar protection of nitrogen gas, be heated to 200 ℃ and keep 6h, make bismuth nitrate complete hydrolysis or alcoholysis, open venting valve discharge solvent then and obtain dry Bi
20TiO
32The presoma of nano material respectively washs this presoma 3 times with ethanol and deionized water more successively, and dry back is at 300 ℃ of following roasting crystallization 4h, to be cooled take out to the room temperature single-phase bismuth titanate Bi
20TiO
32Nano material 3.80g, productive rate are 97.1%.
Embodiment 2:
Take by weighing 8.0g bismuth nitrate (Bi (NO
3)
35H
2O) join in the formic acid, making bismuth/carboxylic acid mol ratio is 1: 40, after constantly being stirred to bismuth nitrate and dissolving fully again to wherein dropwise adding tetraisopropyl titanate; Making titanium/bismuth mol ratio is 1: 13; Continue to stir after the clarified solution to injecting structure directed agents p-nitrophenyl methyl alcohol wherein, making bismuth/pure mol ratio is 1: 4, in above-mentioned solution, adds urea at last; The mol ratio that makes bismuth/urea is 1: 2.2, is stirred to the solution clear then.Prepared solution is injected in the 200mL methanol solvate, mixes the back and move in the autoclave, under the 10bar protection of nitrogen gas, be heated to 235 ℃ and keep 4h, make bismuth nitrate complete hydrolysis or alcoholysis, open venting valve discharge solvent then and obtain dry Bi
20TiO
32The presoma of nano material respectively washs this presoma 3 times with ethanol and deionized water more successively, and dry back is at 280 ℃ of following roasting crystallization 8h, to be cooled take out to the room temperature single-phase bismuth titanate Bi
20TiO
32Nano material 3.79g, productive rate are 96.9%.
Embodiment 3:
Take by weighing 10.0g bismuth nitrate (Bi (NO
3)
35H
2O) join in the propionic acid, making bismuth/carboxylic acid mol ratio is 1: 70, after constantly being stirred to bismuth nitrate and dissolving fully again to wherein dropwise adding butyl titanate; Making titanium/bismuth mol ratio is 1: 8; Continue to stir after the clarified solution to injecting structure directed agents benzyl carbinol wherein, making bismuth/pure mol ratio is 1: 3, in above-mentioned solution, adds urea at last; The mol ratio that makes bismuth/urea is 1: 3.5, is stirred to the solution clear then.Prepared solution is injected in the 250mL propyl alcohol solvent, mixes the back and move in the autoclave, under the 11bar protection of nitrogen gas, be heated to 240 ℃ and keep 3h, make bismuth nitrate complete hydrolysis or alcoholysis, open venting valve discharge solvent then and obtain dry Bi
20TiO
32The presoma of nano material respectively washs this presoma 3 times with ethanol and deionized water more successively, and dry back is at 500 ℃ of following roasting crystallization 3h, to be cooled take out to the room temperature single-phase bismuth titanate Bi
20TiO
32Nano material 4.69g, productive rate are 96.0%.
Embodiment 4:
Take by weighing 10.0g bismuth nitrate (Bi (NO
3)
35H
2O) join in the formic acid, making bismuth/carboxylic acid mol ratio is 1: 60, after constantly being stirred to bismuth nitrate and dissolving fully again to wherein dropwise adding tetraisopropyl titanate; Making titanium/bismuth mol ratio is 1: 13; Continue to stir after the clarified solution to the injecting structure directed agents tert-butyl alcohol wherein, making bismuth/pure mol ratio is 1: 3, in above-mentioned solution, adds urea at last; The mol ratio that makes bismuth/urea is 1: 4, is stirred to the solution clear then.Prepared solution is injected in the 280mL alcohol solvent, mixes the back and move in the autoclave, under the 12bar protection of nitrogen gas, be heated to 250 ℃ and keep 2h, make bismuth nitrate complete hydrolysis or alcoholysis, open venting valve discharge solvent then and obtain dry Bi
20TiO
32The presoma of nano material respectively washs this presoma 3 times with ethanol and deionized water more successively, and dry back is at 400 ℃ of following roasting crystallization 2h, to be cooled take out to the room temperature single-phase bismuth titanate Bi
20TiO
32Nano material 4.73g, productive rate are 96.8%.
Embodiment 5:
Take by weighing 5.2g bismuth chloride (BiCl
3) join in the formic acid, making bismuth/carboxylic acid mol ratio is 1: 50, after constantly being stirred to bismuth chloride and dissolving fully again to wherein dropwise adding tetraisopropyl titanate; Making titanium/bismuth mol ratio is 1: 12; Continue to stir after the clarified solution to injecting structure directed agents p-nitrophenyl methyl alcohol wherein, making bismuth/pure mol ratio is 1: 4, in above-mentioned solution, adds urea at last; The mol ratio that makes bismuth/urea is 1: 5, is stirred to the solution clear then.Prepared solution is injected in the 234mL methanol solvate, mixes the back and move in the autoclave, under the 11bar protection of nitrogen gas, be heated to 235 ℃ and keep 6h, make bismuth chloride complete hydrolysis or alcoholysis, open venting valve discharge solvent then and obtain dry Bi
20TiO
32The presoma of nano material respectively washs this presoma 3 times with ethanol and deionized water more successively, and dry back is at 380 ℃ of following roasting crystallization 8h, to be cooled take out to the room temperature single-phase bismuth titanate Bi
20TiO
32Nano material 3.81g, productive rate are 97.5%.
Embodiment 6:
Take by weighing 5.8g bismuth sulfate (Bi
2(SO
4)
3) join in the acetate; Making bismuth/carboxylic acid mol ratio is 1: 65; Again to wherein dropwise adding butyl titanate, making titanium/bismuth mol ratio is 1: 10 after constantly being stirred to bismuth sulfate and dissolving fully, continue to stir after the clarified solution to injecting structure directed agents phenmethylol wherein; Making bismuth/pure mol ratio is 1: 4.5, is stirred to the solution clear then.Prepared solution is injected in the 230mL alcohol solvent, mixes the back and move in the autoclave, under the 12bar protection of nitrogen gas, be heated to 200 ℃ and keep 4h, make bismuth sulfate complete hydrolysis or alcoholysis, open venting valve discharge solvent then and obtain dry Bi
20TiO
32The presoma of nano material respectively washs this presoma 3 times with ethanol and deionized water more successively, and dry back is at 440 ℃ of following roasting crystallization 7h, to be cooled take out to the room temperature single-phase bismuth titanate Bi
20TiO
32Nano material 3.80g, productive rate are 97.6%.
It is pure that agents useful for same is analysis among the above embodiment 1-6.
Embodiment 7:
Take by weighing the prepared Bi of 50mg embodiment 1
20TiO
32It is 1.14 * 10 that nano material joins 50mL concentration
-4In the aqueous solution of the organic dyestuff reactive brilliant red X3B of mol/L, lucifuge stirs 40min to reach Bi
20TiO
32Nano material is to the adsorption equilibrium of reactive brilliant red X3B; Shine with 350W xenon lamp simulated solar spectrum then; Carry out photocatalytic degradation reaction, in the time of appointment, take a sample, the concentration of residual activity bright red X3B is measured when centrifugalizing out behind the catalyst with ultraviolet-uisible spectrophotometer sampling.Degradation rate=(initial activity bright red X3B concentration-residual activity bright red X3B concentration) * 100%/initial activity bright red X3B concentration.The result shows that degradation rate is 99.2% behind the sunlight catalytic degrading activity bright red X3B 30min.
Embodiment 8:
Take by weighing the prepared Bi of 50mg embodiment 1-4
20TiO
32It is 1 * 10 that the homogeneous mixture of nano material joins 50mL concentration
-4In the aqueous solution of the organic dyestuff rhodamine B (RhB) of mol/L, lucifuge stirs 40min to reach Bi
20TiO
32Nano material is to the adsorption equilibrium of RhB; Shine with 350W xenon lamp simulated solar spectrum then; Carry out photocatalytic degradation reaction, in the time of appointment, take a sample, the concentration of residual RhB is measured when centrifugalizing out behind the catalyst with ultraviolet-uisible spectrophotometer sampling.Degradation rate=(Initial R hB concentration-residual RhB concentration) * 100%/Initial R hB concentration.The result shows that degradation rate is 99.0% behind the sunlight catalytic degraded RhB60min.
Embodiment 9:
Take by weighing the prepared Bi of 50mg embodiment 5-6
20TiO
32It is 1 * 10 that the homogeneous mixture of nano material joins 50mL concentration
-42 of mol/L, in the 4-chlorophenesic acid aqueous solution, lucifuge stirs 40min to reach Bi
20TiO
32Nano material is to 2; The adsorption equilibrium of 4-chlorophenesic acid; With the irradiation of 350W xenon lamp simulated solar spectrum, carry out the photocatalytic degradation reaction then, in the time of appointment, take a sample; Residual 2 when centrifugalizing out behind the catalyst with ultraviolet-uisible spectrophotometer sampling, the concentration of 4-chlorophenesic acid is measured.Degradation rate=(initial 2,4-chlorophenesic acid concentration-residual 2,4-chlorophenesic acid concentration) * 100%/initial 2,4-chlorophenesic acid concentration.The result shows, sunlight catalytic degraded 2, and degradation rate is 75.5% behind the 4-chlorophenesic acid 90min.
Embodiment 10:
Take by weighing the prepared Bi of 50mg embodiment 1-6
20TiO
32It is 1 * 10 that the homogeneous mixture of nano material joins 50mL concentration
-4In the phenol solution of mol/L, lucifuge stirs 40min to reach Bi
20TiO
32Nano material Pyrogentisinic Acid's adsorption equilibrium; Shine with 350W xenon lamp simulated solar spectrum then; Carry out photocatalytic degradation reaction, in the time of appointment, take a sample, the concentration of residual phenol is measured when centrifugalizing out behind the catalyst with ultraviolet-uisible spectrophotometer sampling.Degradation rate=(initial phenol concentration-residual phenol concentration) * 100%/initial phenol concentration.The result shows that degradation rate is 89.5% behind the sunlight catalytic degradation of phenol 90min.
Embodiment 11:
Take by weighing the prepared Bi of 50mg embodiment 1-6
20TiO
32It is 1 * 10 that the homogeneous mixture of nano material joins 50mL concentration
-4In the organic dyestuff reactive brilliant red X3B aqueous solution of mol/L, lucifuge stirs 40min to reach Bi
20TiO
32Nano material is to the adsorption equilibrium of reactive brilliant red X3B; Then with 350W xenon lamp simulation radiation of visible light after the 420nm optical filter filters; Carry out light-catalyzed reaction; In the time of appointment, take a sample, the concentration of residual activity bright red X3B is measured when centrifugalizing out behind the catalyst with ultraviolet-uisible spectrophotometer sampling.Degradation rate=(initial activity bright red X3B concentration-residual activity bright red X3B concentration) * 100%/initial activity bright red X3B concentration.The result shows that degradation rate is 98.2% behind the visible light photocatalytic degradation reactive brilliant red X3B 90min.
Embodiment 12:
With used Bi among the embodiment 7
20TiO
32Behind nano-photocatalyst filtration and the washing and drying, repeat embodiment 7, after the end, reclaim and repeat embodiment 7 more repeatedly, to investigate the regenerability of this catalyst, the result sees table 1:
Table 1
Annotate: n is the recycling number of times, and η is a degradation rate.