CN104722317A

CN104722317A - Bi12O17Br2-Bi24O31Br10 heterojunction photocatalyst and preparation method thereof

Info

Publication number: CN104722317A
Application number: CN201510019634.6A
Authority: CN
Inventors: 彭银; 俞翩翩; 陈庆国
Original assignee: Anhui Normal University
Current assignee: Anhui Normal University
Priority date: 2015-01-14
Filing date: 2015-01-14
Publication date: 2015-06-24
Anticipated expiration: 2035-01-14
Also published as: CN104722317B

Abstract

The invention relates to a Bi12O17Br2-Bi24O31Br10 heterojunction photocatalyst and a preparation method thereof. The preparation method comprises the following steps: (1) preparing a bismuth nitrate solution; (2) adding an aqueous solution of sodium oxalate into the bismuth nitrate solution; (3) cooling and drying after the reaction in the step (2) so as to obtain a precursor; (4) dissolving the precursor and bismuth salt into water and reacting; (5) cooling and drying; (6) forging substances obtained in the step (5) so as to obtain a Bi12O17Br2-Bi24O31Br10 heterojunction. The synthesis method of the Bi12O17Br2-Bi24O31Br10 heterojunction is novel, and degrades rhodamine B dye in a short time completely; compared with any photocatalyst applied to sewage treatment sold on the market at present, incomparable degrading capability is shown.

Description

A kind of Bi 12o 17br 2-Bi 24o 31br 10heterojunction photocatalyst and preparation method thereof

Technical field

The present invention relates to nano composite material and preparation method thereof, be specifically related to a kind of Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀heterojunction photocatalyst and preparation method thereof.

Background technology

As the green technology in new forms of energy conversion and depollution of environment practical application--conductor photocatalysis effect has attracted more and more concern all over the world.But the Quick Casting of the photo-generated carrier of single semiconductor seriously inhibits its photocatalysis performance.It is synthesize the catalyst with high light catalytic activity to provide possibility that the two kinds of catalyst that are coupled form heterojunction structure.This method has following advantage: (1) realizes effective separation of electric charge, and (2) obtain high degradation capability and deep oxidation ability by utilizing visible ray simultaneously, and (3) can arrange in pairs or groups multiple catalysts.Hetero-junctions catalyst can effectively improve electron-hole separation and expand light abstraction width obtain sufficient proof.

Recently, research finds, the oxyhalide of bismuth has excellent catalytic activity in wastewater treatment and indoor air purification.This compounds effectively can not only absorb sunshine, and chemical stability, and photostability is high, nontoxic, and cost is low, and anti-light etching.It is the ideal candidates material of industrial photochemical catalyst.The V – VI – VII ternary oxide semiconductor that bismuth oxyhalide (as a BiOX) class is important, has special layer structure, has self-built internal electric field in the direction perpendicular to layer.The existence of same electric field will effectively improve the right rate of departure of photo-generate electron-hole, thus significantly improves photocatalytic activity and the chemical property of bismuth oxyhalide.

Although the synthesis of stoichiometric compound BiOX and character and the existing large quantity research of application, about non-stoichiometric bismuth oxyhalogen compound as Bi ₁₂o ₁₇br ₂, Bi ₅o ₇br, Bi ₂₄o ₃₁br ₁₀and Bi ₄o ₅br ₂synthetic method, optics and Photocatalytic Performance Study are less.But these a small amount of research work fully show, this kind of nonstoichiometric compound shows more excellent photocatalysis performance than whole than BiOX compound.If the heterojunction composite of this compounds can be obtained, its catalytic activity can be predicted by smallpox on brocade.

Summary of the invention

First technical problem to be solved by this invention is a kind of Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀the preparation method of hetero-junctions.Second technical problem to be solved by this invention is to provide reusable Bi repeatedly ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀hetero-junctions.Concrete technical scheme is as follows:

A kind of Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀the preparation method of hetero-junctions, comprises the steps:

(1) bismuth nitrate solution is prepared;

(2) aqueous solution of sodium oxalate is joined in bismuth nitrate solution;

(3), after step (2) reaction terminates, cooling is also dry, obtains presoma;

(4) presoma and bismuth salt to be dissolved in water and to react;

(5) cooling is also dry;

(6) calcining of step (5) gained material is obtained Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀hetero-junctions.

Further, in step (1), take bismuth salt 2-3g, add water and dissolve completely.

Further, in step (2), the aqueous solution of sodium oxalate is dropwise joined in bismuth nitrate solution, mixes.

Further, in step (2), the aqueous solution of 1-2g sodium oxalate is dropwise joined in bismuth nitrate solution, at 100-150 DEG C of reaction 30-40 hour.

Further, in step (3) and/or (5), naturally cool to room temperature, product distilled water, ethanol washs, and is dried to constant weight.

Further, in step (4), acetum and/or KBr is also added.

Further, in step (4), 0.1-1g presoma and 0.03-0.2g bismuth salt are dissolved in the water of 10-40ml.

Further, add the acetum of 0.5-5ml, then add 0.001-0.1g KBr, by above-mentioned mixed solution at 100-150 DEG C of reaction 15-30 hour.

Further, in step (6), at 300-500 DEG C of calcining 1-3 hour; And/or described bismuth salt is bismuth chloride, bismuth nitrate, one or several mixture of bismuth sulfate.

A kind of Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀heterojunction photocatalyst, adopts said method to prepare.

Compared with currently available technology, Bi of the present invention ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀hetero-junctions synthetic method novelty is also degraded at short notice to rhdamine B completely.This product shows unrivaled degradation capability compared with applying to the photochemical catalyst of sewage disposal with current commercially available any one.

Accompanying drawing explanation

Fig. 1 is Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀the powder diagram (XRD) of hetero-junctions;

Fig. 2 is Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀the electron scanning video picture figure (SEM) of hetero-junctions;

Fig. 3 is Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀the transmission plot (TEM) (a, b) of hetero-junctions and electronic energy spectrum (EDX) (c);

Fig. 4 is Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀hetero-junctions solid UV-Vis diffuse reflection spectroscopy figure;

Fig. 5 is Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀the ultraviolet-visible light spectrogram of heterojunction photocatalysis rhodamine B degradation (RhB);

Fig. 6 is Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀hetero-junctions is to rhodamine B photocatalytic degradation recycling rate of waterused figure;

Fig. 7 is theoretical explanation schematic diagram of the present invention.

Detailed description of the invention

Describe the present invention with reference to the accompanying drawings below, it is a kind of preferred embodiment in numerous embodiments of the present invention.

Take bismuth salt (2-3g), add water to dissolve completely, the aqueous solution of sodium oxalate (1-2g) is dropwise joined in bismuth nitrate solution, mixes, at 100-150 DEG C of reaction 30-40 hour, after reaction terminates, naturally cool to room temperature, product distilled water, ethanol washs, be dried to constant weight, obtain presoma; Take appropriate presoma (0.1-1g) and bismuth salt (0.03-0.2g) is dissolved in a certain amount of water (10-40ml), add a certain amount of acetic acid (0.5-5ml) solution, add appropriate KBr (0.001-0.1g) again, by above-mentioned mixed solution at 100-150 DEG C of reaction 15-30 hour, after reaction terminates, naturally cool to room temperature, product distilled water, ethanol washs, and is dried to constant weight.By gained material at 300-500 DEG C of calcining 1-3 hour, obtain Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀hetero-junctions.Described bismuth salt is bismuth chloride, bismuth nitrate, one or several mixture of bismuth sulfate.

Be presoma see Fig. 2, a, c, e, b, d, f are the sample after calcining, and after can it is evident that calcining, nanometer sheet is long in nanometer rods uniformly, forms homogeneous Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀hetero-junctions.See Fig. 5, in two hours, rhodamine B is completely degraded.See Fig. 6, circulate to lose afterwards for 6 times and only have 2%.First long at Bi (OHC by hydro-thermal method see Fig. 7, BiOBr nanometer sheet ₂o ₄) 2H ₂o nanometer rods also generates BiOBr-Bi (OHC ₂o ₄) 2H ₂o hetero-junctions.Through calcining Bi (OHC ₂o ₄) 2H ₂o nanometer rods becomes Bi ₂o ₃, with this simultaneously, BiOBr and bismuth oxide reaction generate Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀hetero-junctions.

Above by reference to the accompanying drawings to invention has been exemplary description; obvious specific implementation of the present invention is not subject to the restrictions described above; as long as have employed the various improvement that method of the present invention is conceived and technical scheme is carried out; or directly apply to other occasion, all within protection scope of the present invention without improving.

Claims

1. a Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀the preparation method of hetero-junctions, is characterized in that, comprises the steps:

(1) bismuth nitrate solution is prepared;

(2) aqueous solution of sodium oxalate is joined in bismuth nitrate solution;

(3), after step (2) reaction terminates, cooling is also dry, obtains presoma;

(4) presoma and bismuth salt to be dissolved in water and to react;

(5) cooling is also dry;

2. Bi as claimed in claim 1 ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀the preparation method of hetero-junctions, is characterized in that, in step (1), takes bismuth salt 2-3g, adds water and dissolve completely.

3. Bi as claimed in claim 1 or 2 ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀the preparation method of hetero-junctions, is characterized in that, in step (2), is dropwise joined in bismuth nitrate solution by the aqueous solution of sodium oxalate, mixes.

4. Bi as claimed in claim 2 ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀the preparation method of hetero-junctions, is characterized in that, in step (2), is dropwise joined in bismuth nitrate solution by the aqueous solution of 1-2g sodium oxalate, at 100-150 DEG C of reaction 30-40 hour.

5. the Bi according to any one of claim 1-4 ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀the preparation method of hetero-junctions, is characterized in that, in step (3) and/or (5), naturally cools to room temperature, product distilled water, and ethanol washs, and is dried to constant weight.

6. the Bi according to any one of claim 1-5 ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀the preparation method of hetero-junctions, is characterized in that, in step (4), also adds acetum and/or KBr.

7. the Bi according to any one of claim 1-6 ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀the preparation method of hetero-junctions, is characterized in that, in step (4), 0.1-1g presoma and 0.03-0.2g bismuth salt is dissolved in the water of 10-40ml.

8. Bi as claimed in claims 6 or 7 ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀the preparation method of hetero-junctions, is characterized in that, adds the acetum of 0.5-5ml, then adds 0.001-0.1g KBr, by above-mentioned mixed solution at 100-150 DEG C of reaction 15-30 hour.

9. the Bi according to any one of claim 1-8 ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀the preparation method of hetero-junctions, is characterized in that, in step (6), at 300-500 DEG C of calcining 1-3 hour; And/or described bismuth salt is bismuth chloride, bismuth nitrate, one or several mixture of bismuth sulfate.

10. a Bi ₁₂o ₁₇br ₂-Bi ₂₄o ₃₁br ₁₀heterojunction photocatalyst, is characterized in that, adopts method as described in claim 1-9 to prepare.