CN103332739A

CN103332739A - Bi2Sn2O7 composite oxide with unique morphology and preparation method thereof

Info

Publication number: CN103332739A
Application number: CN2013102768919A
Authority: CN
Inventors: 韩巧凤; 汪信; 杨丽丽; 赵靳; 朱俊武; 武晓东; 卑凤利; 刘孝恒
Original assignee: Nanjing University of Science and Technology
Current assignee: Nanjing University of Science and Technology
Priority date: 2013-07-03
Filing date: 2013-07-03
Publication date: 2013-10-02

Abstract

The invention relates to a preparation method of a pyrochlore type composite oxide nanocrystal, and especially hollow spherical Bi2Sn2O7 composite oxide nanocrystal prepared by using ammonia as a reaction medium through a hydrothermal method. The preparation method of the Bi2Sn2O7 composite oxide comprises the following steps: adding ammonia into a BiCl2 water solution in a volume ratio of 1:1-1:2, and stirring evenly; dissolving NaSnO3 in the above solution; reacting the reaction liquid in an autoclave at 180 DEG C; and after the reaction, washing the obtain the hollow spherical Bi2Sn2O7 composite oxide. The Bi2Sn2O7 composite oxide obtained through reaction of the two media has a unique morphology and can effectively improve the photocatalytic properties of materials. The product obtained by using the method shows good catalytic degradation activity on rhodamine B under visible light excitation in a photocatalytic performance test, so as to demonstrate that the oxide has a good application prospect in photocatalytic degradation of pollutants.

Description

A kind of Bi of unique pattern 2Sn 2O 7Composite oxides and preparation method thereof

Technical field

The present invention relates to a kind of Bi ₂Sn ₂O ₇The Bi of composite oxides and preparation method thereof, particularly a kind of unique pattern ₂Sn ₂O ₇Composite oxides and preparation method thereof belong to field of inorganic nano-material preparation.

Background technology

In recent years, the synthetic extensive concern that has been subjected to of control that has the nano material of unique microscopic appearance.Wherein, pyrochlore type multiple oxide, owing to have high chemical stability, high-melting-point, relatively low conduction temperature, good ionic conducting property etc., at aspects such as high temperature solid oxide fuel cell, gas sensor, normal pressure electrochemical method synthetic ammonia huge potential using value arranged.

At present relevant pyrochlore-type Bi ₂Sn ₂O ₇The bibliographical information of the preparation of composite oxides and performance study aspect is less, and the preparation method of bibliographical information mainly contains the hydrothermal synthesis method in solid reaction process (mechanically mixing), the alkaline medium, single former material precursor thermal decomposition method.The Bi that these methods are prepared ₂Sn ₂O ₇Pattern all be spherical particle or coacervate, be reaction medium with NaOH as employing hydrothermal synthesis methods such as Wu Jianjuns, prepared solid spherical Bi ₂Sn ₂O ₇Composite oxides, but because its specific surface area is less, this is one for its performance optimization and hinders greatly.

Summary of the invention

The object of the present invention is to provide a kind of Bi of unique pattern ₂Sn ₂O ₇Composite oxides and preparation method thereof.

The technical solution that realizes the object of the invention is: a kind of Bi of unique pattern ₂Sn ₂O ₇Composite oxides, described Bi ₂Sn ₂O ₇Composite oxides are hollow ball-shape.

Utilize soft chemical method to prepare above-mentioned Bi with unique pattern ₂Sn ₂O ₇The method of composite oxides may further comprise the steps:

Step 1: to BiCl ₂Add ammoniacal liquor in the aqueous solution, stir, obtain uniform solution, wherein the volume ratio of ammoniacal liquor and water is 1:1 ~ 1:2;

Step 2: with NaSnO ₃Be dissolved in the step 1 gained solution;

Step 3: place reactor 180 ℃ of reactions down step 2 solution;

Step 4: reaction finishes the back washing and namely gets hollow ball-shape Bi ₂Sn ₂O ₇Composite oxides.

BiCl in the gained solution in the step 1 ₂Volumetric molar concentration is 0.067mol/L.

NaSnO described in the step 2 ₃With BiCl ₂Mol ratio be 1:1.

Reaction times described in the step 3 is 48h.

The present invention has following remarkable advantage: 1, simple to operate, and the method uniqueness, convenient test need not to add any tensio-active agent, only by changing the Bi that reaction medium has just obtained having unique pattern ₂Sn ₂O ₇Composite oxides; 2, utilizing ammoniacal liquor to be the characteristics that can form bubble in system or granule interior replaces traditional NaOH or KOH preparation to have the hollow ball-shape Bi of bigger serface ₂Sn ₂O ₇Composite oxides.These composite oxides have big specific surface area and ion transport ability, in photocatalysis performance test, shown photocatalytic activity preferably, be expected to have good application in fields such as photocatalytic degradation pollutent and water decomposition hydrogen manufacturing, high temperature solid oxide fuel cell, gas sensors.

Description of drawings

Fig. 1 the present invention utilizes the aqueous ammonia medium hydrothermal preparation to have the Bi of unique pattern ₂Sn ₂O ₇The schematic flow sheet of composite oxides.

The Bi that Fig. 2 Comparative Examples 1 makes ₂Sn ₂O ₇The transmission electron microscope picture of composite oxides.

Fig. 3 is that the present invention obtains product B i ₂Sn ₂O ₇The transmission electron microscope picture of composite oxide nano-crystal sample, wherein a is embodiment 1; B is embodiment 2.

Fig. 4 the present invention obtains product B i ₂Sn ₂O ₇The visible light degraded figure of composite oxides, wherein a is the degradation rate figure of different products; B is that rhodamine B is at Bi ₂Sn ₂O ₇The UV-Vis figure that changes with light application time under the hollow ball catalysis.

Embodiment

Below in conjunction with the drawings and specific embodiments the present invention is described in further detail.

Photocatalytic degradation rate figure is the degradation rate of 50mg different catalysts degraded 10mg/L rhodamine B under the irradiation of 500w xenon lamp

In conjunction with Fig. 1, the present invention utilizes ammoniacal liquor to have the Bi of unique pattern for the reaction medium preparation ₂Sn ₂O ₇The method of composite oxides, its feature may further comprise the steps:

Step 1: ammoniacal liquor is joined BiCl ₂In the aqueous solution, stir, obtain uniform solution, BiCl in the gained solution ₂Volumetric molar concentration be 0.067mol/L; The volume ratio of ammoniacal liquor and water is 1:1 ~ 1:2; The volume ratio of hydrochloric acid and water is 1:10;

Step 2: with NaSnO ₃Be dissolved in the step 1 gained solution, obtain reaction solution, NaSnO ₃With BiCl in the step 1 ₂Mol ratio be 1:1;

Step 3: with reaction solution isothermal reaction in closed reactor of step 2 gained, temperature of reaction is 180 ℃, and the reaction times is 48h;

Step 4: will namely get the Bi with unique pattern after the resulting product washing of step 3 ₂Sn ₂O ₇Composite oxides.

The present invention will be further described in detail below in conjunction with embodiment, Comparative Examples and accompanying drawing:

Embodiment 1:

Step 1: 10mL ammoniacal liquor is joined 20mLBiCl ₂In the aqueous solution, stir, obtain uniform solution, BiCl in the gained solution ₂Volumetric molar concentration be 0.067mol/L;

Step 2: with 2mmol NaSnO ₃Be dissolved in the solution that step 1 obtains, obtain reaction solution;

Step 3: with reaction solution isothermal reaction in closed reactor of step 2 gained, 180 ℃ of temperature of reaction, the reaction times is 48h;

Step 4: will namely get hollow ball-shape Bi after the resulting product washing of step 3 ₂Sn ₂O ₇Composite oxides.

Shown in the transmission electron microscope picture 3 (a) of products therefrom, product has formed the hollow ball shape structure of being made up of small-particle.By photocatalytic degradation Fig. 4 (a) as can be seen, the rhodamine B degradation rate is 55% during 2.5 h.

Embodiment 2:

Step 1: 12mL ammoniacal liquor is joined 18mL BiCl ₂In the aqueous solution, stir, obtain uniform solution, BiCl in the gained solution ₂Volumetric molar concentration be 0.067mol/L;

Step 2: with 2mmol NaSnO ₃Be dissolved in the suspension that step 1 obtains, obtain reaction solution;

Shown in the transmission electron microscope picture 3 (b) of products therefrom, product has formed the hollow ball-shape structure of being made up of small-particle.By photocatalytic degradation Fig. 4 (a), 4 (b) as can be seen, the rhodamine B degradation rate has reached 75% during 4.5 h, and compare its photocatalytic activity with Comparative Examples better.

Embodiment 3:

Step 1: 15mL ammoniacal liquor is joined 15mLBiCl ₂In the aqueous solution, stir, obtain uniform solution, BiCl in the gained solution ₂Volumetric molar concentration be 0.067mol/L;

Products therefrom has formed the hollow ball-shape structure of being made up of small-particle equally.

Comparative Examples 1:

Step 1: 15mL0.4 mol/LKOH solution is joined 15mLBiCl ₂In the aqueous solution, stir, obtain uniform solution, BiCl in the gained solution ₂Volumetric molar concentration be 0.067mol/L;

Step 4: will namely get solid spherical nanometer Bi after the resulting product washing of step 3 ₂Sn ₂O ₇Composite oxides.

Shown in the transmission electron microscope picture 2 of products therefrom, product has formed solid spherical.By photocatalytic degradation Fig. 4 (a) as can be seen, degradation rate only is 25% during 4.5 h, and product photochemical catalysis effect is relatively poor, not as the made hollow ball-shape structure of the present invention.

Comparative Examples 2:

Step 3: with reaction solution isothermal reaction in closed reactor of step 2 gained, 180 ℃ of temperature of reaction, the reaction times is 24h;

Products therefrom has formed solid spherical equally.By photocatalytic degradation Fig. 4 (a) as can be seen, degradation rate only is 25% also during 4.5 h, and product photochemical catalysis effect is relatively poor.

Claims

1. the Bi of a unique pattern ₂Sn ₂O ₇Composite oxides is characterized in that described Bi ₂Sn ₂O ₇Composite oxides have the hollow ball-shape microtexture.

2. the Bi of unique pattern according to claim 1 ₂Sn ₂O ₇Composite oxides is characterized in that described composite oxides adopt the following steps preparation:

Step 1: to BiCl ₂Add ammoniacal liquor or hydrochloric acid in the aqueous solution, stir, obtain uniform solution, wherein the volume ratio of ammoniacal liquor and water is 1:1 ~ 1:2; The volume ratio of hydrochloric acid and water is 1:10;

Step 2: with NaSnO ₃Be dissolved in the step 1 gained solution;

Step 3: place reactor 180 ℃ of reactions down step 2 solution;

3. the Bi of unique pattern according to claim 2 ₂Sn ₂O ₇Composite oxides is characterized in that in the step 1 BiCl in the gained solution ₂Volumetric molar concentration is 0.067mol/L.

4. the Bi of unique pattern according to claim 2 ₂Sn ₂O ₇Composite oxides is characterized in that the NaSnO described in the step 2 ₃With BiCl ₂Mol ratio be 1:1.

5. the Bi of unique pattern according to claim 2 ₂Sn ₂O ₇Composite oxides is characterized in that the reaction times described in the step 3 is 48h.

6. the Bi of a unique pattern ₂Sn ₂O ₇The preparation method of composite oxides is characterized in that adopting soft chemical method, and its concrete preparation process is:

Step 2: with NaSnO ₃Be dissolved in the step 1 gained solution;

Step 3: place reactor 180 ℃ of reactions down step 2 solution;

7. the Bi of unique pattern according to claim 6 ₂Sn ₂O ₇The preparation method of composite oxides is characterized in that in the step 1 BiCl in the gained solution ₂Volumetric molar concentration is 0.067mol/L.

8. the Bi of unique pattern according to claim 6 ₂Sn ₂O ₇The preparation method of composite oxides is characterized in that the NaSnO described in the step 2 ₃With BiCl ₂Mol ratio be 1:1.

9. the Bi of unique pattern according to claim 6 ₂Sn ₂O ₇The preparation method of composite oxides is characterized in that the reaction times described in the step 3 is 48h.