CN103418381A

CN103418381A - High-performance Ag2O/Bi2WO6 compound light catalyst and preparing method thereof

Info

Publication number: CN103418381A
Application number: CN2013103748185A
Authority: CN
Inventors: 张国英; 吴青松; 崔燕
Original assignee: Tianjin Normal University
Current assignee: Tianjin Normal University
Priority date: 2013-08-26
Filing date: 2013-08-26
Publication date: 2013-12-04
Anticipated expiration: 2033-08-26
Also published as: CN103418381B

Abstract

The invention discloses a high-performance Ag2O/Bi2WO6 compound light catalyst and a simple preparing method thereof. The method comprises the steps that AgNO3 and NaOH of equal stoichiometric ratio serve as initial reactants at room temperature under the condition of ordinary pressure, chemical depositing is performed on the surfaces of Bi2WO6 particles in a one-step mode to generate Ag2O by utilizing ultra instability of AgOH, and the Ag2O/Bi2WO6 compound light catalyst is obtained. Research results show that not only can Ag2O modification broaden the visible light absorption range of the Bi2WO6, but also the compounding probability of photon-generated carriers of a semiconductor can be effectively inhibited. Furthermore, the photocatalytic activity of the compound catalyst is obviously improved when the mass percent of the chemical element Ag is within the range of 0.2%-3.4%, when an Ag wt. % equals 0.6 %, the photocatalytic activity is optimized, and the kinetic constant of the photocatalytic activity is 4.7 times of the net Bi2WO6. Moreover, the compound light catalyst shows good reusability in degrading organic dyestuffs. The simple preparing method of the high-performance Ag2O/Bi2WO6 compound light catalyst and the reusability predict good application prospects of the compound light catalyst.

Description

High-performance Ag 2O/Bi 2WO 6Composite photo-catalyst and preparation method thereof

Technical field

The invention belongs to water pollution resist technology field, relate to the treatment technology of industry water, more specifically say a kind of high-performance Ag ₂O/Bi ₂WO ₆Composite photo-catalyst and preparation method thereof.

Background technology

The caused water pollution of industrial production develop rapidly is one of society problem demanding prompt solution.Than Treatment of Industrial Water technology such as biochemical process at present commonly used, the precipitation method, photocatalytic oxidation is the advantages such as energy consumption is low, purification condition is gentle, non-secondary pollution, deep oxidation because having, and have become the key technology that solves the ambient water pollution problem.Tradition photochemical catalyst TiO ₂Because of band-gap energy wider (3.0 ~ 3.2 eV), can only utilize in sunshine the ultraviolet light that accounts for 3%, too low to the utilization rate of solar energy, research and development visible ray (accounting for sunshine 45%) response type semiconductor light-catalyst has enjoyed attention.

Bismuth based semiconductor Bi ₂WO ₆Band-gap energy is 2.69 eV approximately, can respond the visible ray of 420-460 nm, are a kind of novel visible responsive photocatalysts.In a large number for Bi ₂WO ₆The research of micro nano structure all shows that this semiconductor pollutes process field at water and has a good application prospect.But for this unitary system, the problem that still exists following two needs to solve: the one, it absorbs only about 460 nm of threshold value, still lower to the utilization rate of solar energy; The 2nd, in semiconductor, the recombination rate in light induced electron-hole is very fast, makes photo-quantum efficiency still relatively low.The existence of these two problems makes Bi ₂WO ₆The further raising of photocatalytic activity is subject to Bottleneck Restrictions.Therefore, widen Bi ₂WO ₆Visible light-responded scope, promote effective separation and the transfer in light induced electron-hole, be to need the key issue solved in this catalyst research at present.

Research shows Bi ₂WO ₆Carry out metal-oxide semiconductor (MOS) compound, can effectively widen its visible absorption scope, and utilize the band gap overlap effect between different semiconductors to promote light induced electron-hole effectively to separate, thereby improve Bi ₂WO ₆Photocatalytic activity.As the Co reported ₃O ₄, TiO ₂, WO ₃, Bi ₂O ₃Deng metal oxide to Bi ₂WO ₆Compound rear certain cooperative photocatalysis effect that all shows.Than above-mentioned conductor oxidate, Ag ₂O is the semiconductor of a kind of band-gap energy narrower (1.2eV), has wider visible light-responded interval, and we are from the angle theoretical prediction of " definitely electronegativity " itself and Bi ₂WO ₆Band gap position with coupling, therefore study Ag ₂O and Bi ₂WO ₆compoundly there is important theoretical and practical significance.Yu Jiaguo etc. have reported by infusion process and have prepared Ag in the recent period ₂The Bi that O modifies ₂WO ₆, performance the best of photo-catalytic degradation of methyl-orange when discovery Ag wt.% is 11.8%, its pseudo first order reaction kinetic constant is 0.0163 min ^-1.Because this method relates to first at Bi ₂WO ₆Surface impregnation AgNO ₃, and then carry out 350 ℃ of calcinations and process, preparation process not only relatively loaded down with trivial details, expend the energy, and Ag content is higher, is unfavorable for economization production.

In earlier stage high-performance Bi prepared with us by the present invention ₂WO ₆Photochemical catalyst is basis, in line with simplifying preparation technology, save the energy, reducing the Ag constituent content and put forward high performance angle, by room temperature one step solution reaction, has realized Ag ₂O and Bi ₂WO ₆Semi-conductive compound, find that Ag wt.% photocatalytic activity in the scope of 0.2-3.4% all obviously improves, photocatalytic activity the best during wherein compound content 0.6%, its kinetic constant is 0.24 min ^-1, reach pure Bi ₂WO ₆4.7 times of sample.

Summary of the invention

For achieving the above object, the invention discloses following technology contents:

High-performance Ag ₂O/Bi ₂WO ₆Composite photo-catalyst, is characterized in that it is at Bi ₂WO ₆The particle surface chemical deposition generates Ag ₂O, obtain Ag ₂O/Bi ₂WO ₆Composite photo-catalyst; Wherein the mass percent of Ag element is at 0.2-3.4%.

Composite photo-catalyst of the present invention, wherein the mass percent of Ag element is at 0.2-3.4%, Bi ₂WO ₆Particle diameter at the 2-3 micron.Preferably the mass percent of Ag ion is at 0.4-1.0%, the ratio 0.6% be more preferably.

The present invention further discloses high-performance Ag ₂O/Bi ₂WO ₆The preparation method of composite photo-catalyst is characterized in that being undertaken by following step:

Take 0.1g Bi ₂WO ₆The superstructure powder, in beaker, adds 0.59 * 10 wherein ^-3The AgNO of mol/L ₃Storing solution 2.0～34.0mL after at room temperature stirring 20～40 min, then adds 0.25 * 10 in mixture ^-3Mol/L NaOH storing solution 2.0～34.0 mL, after continuing stirring reaction 20～40 min, by precipitation and centrifugal separation, washing, 60 ℃ of dryings, collect the Ag that the gained powder obtains serial different composite ratio ₂O/Bi ₂WO ₆Composite photo-catalyst; Described composite photocatalyst agent content is with Ag element and Bi ₂WO ₆The mass percent of powder is 0.2～3.4%.Preferably the composite photocatalyst agent content is with Ag element and Bi ₂WO ₆The mass percent of powder is 0.4～1.0%, and optimal proportion is 0.6%.

The present invention further discloses high-performance Ag ₂O/Bi ₂WO ₆Composite photo-catalyst is in the application prepared aspect degradating organic dye.Application in the refractory organics aromatic compounds particularly contained in preparation degraded printing and dyeing workshop institute sewer.This composite photo-catalyst shows good recycling property aspect degradating organic dye.This method is the simple and easy deposition of room temperature one step, has lower Ag load capacity and excellent photocatalysis performance, and these advantages are indicating the applications well prospect of this photochemical catalyst in the Industrial Wastewater Treatment field.

The present invention is more detailed to be described below:

1. general introduction

High-performance Ag prepared by the present invention ₂O/Bi ₂WO ₆Composite photo-catalyst, it is under the room temperature condition of normal pressure, to wait AgNO of metering ratio ₃As initial reactant, utilize the utmost point unstability of AgOH, at Bi with NaOH ₂WO ₆Particle surface one step chemical deposition generates Ag ₂O, obtain Ag ₂O/Bi ₂WO ₆Composite photo-catalyst.Result of study shows Ag ₂O modifies and has not only widened Bi ₂WO ₆The visible absorption scope, and semi-conductive photo-generated carrier recombination probability has obtained effective inhibition.In Ag element mass percent, be in the 0.2-3.4% scope, the photocatalytic activity of composite catalyst all obviously improves, photocatalytic activity the best during Ag wt.% 0.6% wherein, and its kinetic constant is pure Bi ₂WO ₆4.7 times.In addition, this composite photo-catalyst shows good recycling property aspect degradating organic dye.Simple method for preparing and reusable edible have indicated the applications well prospect of this composite photo-catalyst.

2 experimental sections

2.1 the preparation of composite photo-catalyst

This work is to high-performance Bi in early stage ₂WO ₆Powder surface modified.Bi ₂WO ₆Powder refers to the colored shape micro-sphere structure assembled by nanometer sheet, and the preparation method is shown in G. Y. Zhang, et. al Mater. Res. Bull.2012,47:1919.

Take 0.1g Bi ₂WO ₆Powder, in beaker, adds the AgNO of 2.0～34.0 mL different volumes wherein ₃Storing solution (0.59 * 10 ^-3Mol/L), after at room temperature stirring 20～40 min, then to the NaOH storing solution (0.25 * 10 that adds respectively 2.0～34.0 mL different volumes in mixture ^-3Mol/L), after continuing stirring reaction 20～40 min, by precipitation and centrifugal separation, washing, 60 ℃ of dryings, collect the Ag that the gained powder obtains serial different composite ratio ₂O/Bi ₂WO ₆(0.2～3.4%) composite photo-catalyst, wherein compound content is with Ag element and Bi ₂WO ₆The mass percent note of powder.

2.2 photocatalysis performance test

Take above-mentioned series A g ₂O/Bi ₂WO ₆Composite photo-catalyst 5mg, in quartz test tube, adds 10 mL 10 ^-5The RhB solution of M, magnetic agitation 30 min in XPA-7 type photochemical reaction instrument camera bellows, after setting up the adsorption desorption balance of dyestuff and catalyst, start to use the 500W Xenon light shining.Serial photochemical catalyst sample is taken out to the quartz ampoule sample every 10 min, after photocatalyst granular is removed in centrifugation immediately, with ultraviolet-visible spectrophotometer, detect the photon absorbing intensity of supernatant at 553 nm places.

3 results and discussion

3.1 XRD structural analysis

Fig. 1 is Bi ₂WO ₆, Ag ₂O, and Ag ₂O/Bi ₂WO ₆The XRD diffracting spectrum of composite photo-catalyst powder.For ease of detecting Bi ₂WO ₆The Ag of stromal surface ₂The O diffraction maximum, select the higher Ag of Ag constituent content ₂O/Bi ₂WO ₆(10%) sample.The diffraction maximum of a and b sample is all strong and sharp-pointed, and diffractive features and orthorhombic crystal phase Bi ₂WO ₆Standard card (JCPDS No. 73-1126) coincide, show that product is the Bi with higher crystallinity ₂WO ₆, illustrate that room temperature reaction carries out Ag simultaneously ₂The process that O modifies does not affect Bi ₂WO ₆The crystal phase structure of matrix.But due to Ag ₂The strong peak of the master of O and Bi ₂WO ₆Time strong peak substantially overlapping, thereby can not obviously determine Ag from b ₂The existence of O crystalline phase.In order to confirm Ag in composite catalyst ₂The existence of O, to Ag in a, b sample ₂O time strong peak region 37.5～39.5o has carried out local amplification.As shown in the enlarged drawing on the right, the Bi in a ₂WO ₆Matrix only has faint instrumental background noise peak in this zone, and in b, obvious Ag has appearred in this location ₂O(JCPDS No.41-1104) inferior strong peak, susceptible of proof Ag thus ₂O successfully modifies.

3.2 UV-Vis DRS spectral characterization

Fig. 2 is Bi ₂WO ₆, Ag ₂O and different composite ratio Ag ₂O/Bi ₂WO ₆UV-Vis DRS spectrum.Bi ₂WO ₆Therefore precipitous absorption spectrum shape illustrates that it is from the intrinsic band-gap transition, although also show certain absorption at visible region, due to the about 2.7eV of its band-gap energy, absorbs only about 450 nm of band edge, still relatively less to the absorption of visible region.And for Ag ₂O, because it has narrower band-gap energy (1.2 eV), so absorption spectrum ranges is very wide, at the whole ultraviolet-visible wave band of 200-800 nm, stronger absorption is arranged.When to Bi ₂WO ₆Carry out Ag ₂After the finishing of O, Ag ₂O/Bi ₂WO ₆The obvious red shift of absorption band edge of composite photo-catalyst.And, along with the increase of Ag elements compounding ratio, material obviously strengthens at the degree of absorption of visible region.UV-Vis DRS spectrum shows Ag ₂The surface recombination of O has effectively been widened Bi ₂WO ₆To the absorption of visible ray, thereby can more effectively utilize solar energy.

3.3 fluorescence spectrum characterizes

Fluorescence spectrum is commonly used to investigate migration and the recombination process of photo-generated carrier in semiconductor, and the recombination probability that means carrier that weakens of fluorescence intensity reduces.Fig. 3 is Ag under the 320nm ultraviolet excitation ₂The compound front and back Bi of O ₂WO ₆Fluorescence spectrum.Bi ₂WO ₆Show wider blue-green fluorescent emission band at 450-550 nm, wherein the hyperfluorescenceZeng Yongminggaoyingguang peak of 488 nm belongs to excitation electron and returns valence band from the transition of conduction band, thereby causes light induced electron-hole-recombination and the energy that discharges.Bi ₂WO ₆Through surface recombination Ag ₂After O, fluorescence peak shape and compound front basically identical, but fluorescence intensity descends to some extent, and especially the peak intensity of Ag content 0.6% and 1.0% sample reduces obviously, and Ag is described ₂The finishing of O can effectively suppress the compound of electron-hole.But when Ag too high levels (2.2%), the fluorescence intensity of composite photo-catalyst obviously strengthens again on the contrary, and this is to have introduced too much phase defect because too high Ag content means in material, and it can become the complex centre of photo-generated carrier.Therefore, in certain compositely proportional, Ag ₂The compound of O can effectively suppress Bi ₂WO ₆Middle light induced electron and hole in conjunction with probability, thereby improve photo-quantum efficiency.

3.4 different composite ratio Ag ₂O/Bi ₂WO ₆The Performance Ratio of photochemical catalyst

Fig. 4 be serial 5 mg photochemical catalysts under 500W Xe lamp irradiation, photocatalytic degradation 10 ml 10 ^-5The performance comparison of M RhB solution.Blank assay shows RhB in the situation that exist without photochemical catalyst, and after 40min irradiation, degraded has occurred 2.2% the RhB of only having an appointment, and illustrates that the impact of illumination can be ignored; Bi ₂WO ₆To the absorption 10.1% of dye molecule, do not affect the performance comparison of serial photochemical catalyst yet; And pure Ag ₂O catalytic activity under the same conditions is starkly lower than Bi ₂WO ₆, Ag is described ₂The photocatalytic activity of O self is not the reason that causes that the composite photo-catalyst performance improves.More serial Bi ₂WO ₆The performance of based photocatalyst can be found out, surface recombination Ag ₂Bi after O ₂WO ₆Photocatalytic activity all obviously improve, and show the raising along with Ag elements compounding ratio, catalytic degradation efficiency increased substantially before this, then trend in a slight decrease again.For pure Bi ₂WO ₆, after illumination 20min, to the degradation rate of RhB, be also only to reach 87% after 60%, 40min, and Ag ₂O/Bi ₂WO ₆(0.6%) just can't detect the absorbance at 553 nm places after sample illumination 20min.Ag ₂O/Bi ₂WO ₆The photon absorbing intensity of (1.0% and 2.2%) sample RhB after irradiation 40min is also almost nil.According to pseudo first order reaction dynamics (Fig. 4 b), pure Bi ₂WO ₆The degradation reaction speed constant be 0.051 min ^-1, and Ag ₂O/Bi ₂WO ₆(0.6%) speed constant is 0.240 min ^-1, be 4.7 times of compound front sample, demonstrate the optimal light catalytic activity.When compositely proportional is too high, the reaction power mathematic(al) constant obviously reduces again, but still all higher than the Bi without compound ₂WO ₆.As can be seen here, although Ag ₂O and Bi ₂WO ₆Exist good band gap coupling effect between semiconductor, but have balance between the reverse inhibition of its forward promotion and two-dimensional phase defect, therefore selected best complex ratio Ag wt.% is 0.6%.

The stability of photocatalyst for degrading pollutant is to determine one of key factor that can it practical application, the Ag of selectivity the best ₂O/Bi ₂WO ₆(0.6%) product are investigated its reusable edible.Due to Bi ₂WO ₆Superstructure matrix has macroscopical micron-scale, therefore only by low-speed centrifugal or simple filtration, it can be separated from degradation solution.Finishing Ag ₂Bi after O ₂WO ₆Base composite photocatalyst can reclaim in the same way, and only, by reusable after distilled water several times, ethanol washing and 60 ℃ of low temperature dryings, not only mode is easy, has also effectively avoided secondary pollution.Fig. 5 has provided the performance data of this sample through 5 loop cycle.Period 1 was compared with second round, and degradation efficiency does not almost obviously change, and even, in second round, after 30 min irradiation, the absorbance at 553nm place has just reduced to zero; And in period 3 to period 5 circulation respectively to detect data substantially close, degradation efficiency does not reduce.Although rear three cycles were compared with the first two cycle, front 30min decreases to the degradation efficiency of dyestuff, and after light application time extends to 40min, RhB also can degrade complete, does not affect the overall degradation effect to RhB.As can be seen here, Ag ₂O/Bi ₂WO ₆(0.6%) composite photo-catalyst has good photo and thermal stability, and dressing agent Ag ₂O and Bi ₂WO ₆Combination between matrix firmly, therefore shows good recycling property aspect degradation of dye, has a extensive future.

The accompanying drawing explanation:

The XRD collection of illustrative plates that Fig. 1 is serial different samples: (a) Bi ₂WO ₆(b) Ag ₂O/Bi ₂WO ₆(10%); (c) Ag ₂O;

The UV-vis diffuse reflection spectrum that Fig. 2 is different samples;

The fluorescence spectrum that Fig. 3 is different samples (Ex:320 nm);

The photocatalysis performance that Fig. 4 is different samples compares: (a) degradation efficiency; (b) light-catalyzed reaction speed constant;

Fig. 5 is Ag ₂O/Bi ₂WO ₆(0.6%) recyclability of catalyst.

The specific embodiment

In order to explain more fully enforcement of the present invention, provide following preparation method's embodiment.These embodiment explain rather than limit the scope of the invention; Bi wherein ₂WO ₆Powder does not still have commercialization, and its preparation work exists Mater. Res. Bull.2012,47:1919. delivers.

Reference example

Bi ₂WO ₆The preparation method of powder:

Take 0.3881 g(0.8 mmol) Bi (NO ₃) ₃5H ₂O is dissolved in 17 mL distilled water, under violent magnetic agitation, adds wherein 0.1319 g(0.4 mmol) Na ₂WO ₄2H ₂O.After continuing to stir 30 min, white suspension is transferred in the hydrothermal reaction kettle of 25 mL, in 160 ℃ of isothermal reaction 12 h.After naturally cooling to room temperature, by product centrifugation, washing dry, obtain faint yellow Bi ₂WO ₆The superstructure powder.This 5mg photochemical catalyst after 500W Xenon light shining 20min to 10 mL 10 ^-5The degradation rate of M RhB liquid to be measured is 60%.

Ag ₂O/Bi ₂WO ₆The Preparation Example of composite photo-catalyst is as follows.

Embodiment 1

Take 0.1g Bi ₂WO ₆Powder, in 50 mL beakers, adds 2.0 mL (0.59 * 10 ^-3Mol/L) AgNO ₃Storing solution, stir 20min under room temperature, then add and AgNO ₃Deng (0.25 * 10 of metering ratio ^-3Mol/L) NaOH storing solution 2.0 mL, continue to stir 20min, then will precipitate under centrifugal, washing, 60 ℃ dryly, and the collection brown-black powder obtains the Ag that Ag wt.% is 0.2% ₂O/Bi ₂WO ₆Photochemical catalyst.This 5mg photochemical catalyst after 500W Xenon light shining 20min to 10 mL 10 ^-5The degradation rate of M RhB liquid to be measured is 72.6%.

Embodiment 2

Take 0.1g Bi ₂WO ₆Powder, in 50 mL beakers, adds 6.0 mL(0.59 * 10 ^-3Mol/L) AgNO ₃Storing solution, stir 20min under room temperature, then add and AgNO ₃Deng (0.25 * 10 of metering ratio ^-3Mol/L) NaOH storing solution 6.0ml, continue to stir 30min, then will precipitate under centrifugal, washing, 60 ℃ dryly, and the collection brown-black powder obtains the Ag that Ag wt.% is 0.6% ₂O/Bi ₂WO ₆Photochemical catalyst.This 5mg photochemical catalyst after 500W Xenon light shining 20min to 10 mL 10 ^-5The degradation rate of M RhB liquid to be measured is 99.2%.

Embodiment 3

Take 0.1g Bi ₂WO ₆Powder, in the cup of 50 mL, adds (0.59 * 10 ^-3Mol/L) 10.0mLAgNO ₃Storing solution, stir 20min under room temperature, then add and AgNO ₃Deng (0.25 * 10 of metering ratio ^-3Mol/L) NaOH storing solution 10.0ml, continue to stir 40min, then will precipitate under centrifugal, washing, 60 ℃ dryly, and the collection brown-black powder obtains the Ag that Ag wt.% is 1.0% ₂O/Bi ₂WO ₆Photochemical catalyst.This 5mg photochemical catalyst after 500W Xenon light shining 20min to 10 mL 10 ^-5The degradation rate of M RhB liquid to be measured is 92.7%.

Embodiment 4

Take 0.1g Bi ₂WO ₆Powder, in 100 mL beakers, adds 22.0mL(0.59 * 10 ^-3Mol/L) AgNO ₃Storing solution, stir 30min under room temperature, then add and AgNO ₃Deng (0.25 * 10 of metering ratio ^-3Mol/L) NaOH storing solution 22ml, then continue to stir 40min, then will precipitate under centrifugal, washing, 60 ℃ dryly, and the collection brown-black powder obtains the Ag that Ag wt.% is 2.2% ₂O/Bi ₂WO ₆Photochemical catalyst.This 5mg photochemical catalyst after 500W Xenon light shining 20min to 10 mL 10 ^-5The degradation rate of M RhB liquid to be measured is 84.3%.

5mg Bi in the present invention ₂WO ₆The Ag of (being that Ag wt.% is 0) and serial different composite ratio ₂O/Bi ₂WO ₆Photochemical catalyst, after 500W Xenon light shining 20min, to 10 mL 10 ^-5The more detailed degradation rate contrast of M RhB solution is as shown in the table:

Ag ₂O/Bi ₂WO ₆(different Ag wt.%)	Degradation rate (%)
		0	60
0.1	65
		0.2	73
0.4	80
		0.6	99
0.8	92
		1.0	93
1.4	89
		1.8	91
2.2	85
		2.6	90
3.0	88
		3.4	73
3.8	59

From table can reach a conclusion as follows:

Surface recombination Ag ₂After O, Bi ₂WO ₆Photocatalytic activity obviously improve, and along with the increase of Ag wt.% compositely proportional, the degradation rate of Luo Dan name B is also obviously strengthened, wherein the performance of 0.6-1.8% is the highest, degradation rate all reaches more than 90%.When Ag elements compounding ratio is too high, degradation rate presents again obvious downward trend on the contrary, and after compositely proportional reaches 3.8%, performance is not so good as without compound Bi ₂WO ₆Matrix.In addition, from economic angle, Ag elements compounding ratio is lower, and the cost of catalyst is also just lower.Therefore, combination property and economic two aspects, preferred proportion is 0.4-1.0%, the selected Ag wt.% of best complex ratio is 0.6%.

Embodiment 5

The degraded example of the refractory organics aromatic compounds contained in printing and dyeing workshop institute sewer:

Rhodamine B is printing and dyeing industry difficult degradation aromatics orchil commonly used, gets the waste water 500mL that contains red rhdamine B 4.8mg/L from printing and dyeing workshop, adds the Ag that Ag element mass percent is 0.6% ₂O/Bi ₂WO ₆Photochemical catalyst 250 mg, in XPA-7 type photochemical reaction instrument camera bellows, magnetic agitation reaches suction-desorption balance, after 500W xenon lamp simulate solar radiation 20 min, and isolated by filtration immediately, the degradation rate of surveying supernatant absorbance calculating rhodamine B is 97.7%, and pure Bi under equal conditions ₂WO ₆Photocatalytic degradation efficiency be only 59.6%

Embodiment 6

The Ag of selected performance the best ₂O/Bi ₂WO ₆(0.6%) sample, to other dyestuff except Luo Dan name B, comprise that methylene blue and methyl orange also carried out respectively the light degradation experiment under the same terms, and with without compound Bi ₂WO ₆Sample contrasts, and the data obtained is listed as follows:

From the table data can find out, Ag ₂O/Bi ₂WO ₆(0.6%) not only to the degradation efficiency of Luo Dan name B apparently higher than the Bi without compound ₂WO ₆, the degraded of dyestuff methylene blue and methyl orange is shown to same advantage.Illustrate that the composite photo-catalyst in this invention really has a good application prospect in the sewage of degraded printing and dyeing workshop row containing the refractory organics aromatic compounds.

Claims

1. high-performance Ag ₂O/Bi ₂WO ₆Composite photo-catalyst, is characterized in that it is at Bi ₂WO ₆The particle surface chemical deposition generates Ag ₂O, obtain Ag ₂O/Bi ₂WO ₆Composite photo-catalyst; Wherein the mass percent of Ag element is at 0.2-3.4%.

2. right is wanted 1 described composite photo-catalyst, and wherein the mass percent of Ag element is at 0.4-1.0%.

3. the described high-performance Ag of claim 1 ₂O/Bi ₂WO ₆The preparation method of composite photo-catalyst is characterized in that being undertaken by following step:

Take 0.1g Bi ₂WO ₆Powder, in beaker, adds 0.59 * 10 wherein ^-3Mol/L AgNO ₃Storing solution 2.0～34.0mL after at room temperature stirring 20～40 min, then adds 0.25 * 10 in mixture ^-3Mol/L NaOH storing solution 2.0～34.0 mL, after continuing stirring reaction 20～40 min, by precipitation and centrifugal separation, washing, 60 ℃ of dryings, collect the Ag that the gained powder obtains serial different composite ratio ₂O/Bi ₂WO ₆Composite photo-catalyst; Described composite photocatalyst agent content is with Ag element and Bi ₂WO ₆The mass percent of powder is 0.2～3.4%.

4. preparation method claimed in claim 3, wherein the composite photocatalyst agent content is with Ag element and Bi ₂WO ₆The mass percent of powder is 0.4～1.0%.

5. the described high-performance Ag of claim 1 ₂O/Bi ₂WO ₆Composite photo-catalyst is in the application prepared aspect degradating organic dye.

6. the described high-performance Ag of claim 1 ₂O/Bi ₂WO ₆Application in the refractory organics aromatic compounds that composite photo-catalyst contains in preparation degraded printing and dyeing workshop institute sewer.