CN106111114A - A kind of In2O3/Bi2Sn2O7 composite visible light catalyst and its preparation method - Google Patents

Abstract

The invention discloses a kind of type In₂O₃/Bi₂Sn₂O₇Composite visible light catalyst and preparation method thereof, this composite visible light catalyst includes Bi₂Sn₂O₇Granule and Cubic In₂O₃Block；The present invention uses hydro-thermal method and infusion process, i.e. utilizes Bi₂Sn₂O₇As matrix and In (NO)₃Mixture prepares In₂O₃/Bi₂Sn₂O₇Composite photo-catalyst；This composite photo-catalyst can reduce the compound of electron hole pair, it is possible to is effectively improved the utilization rate of sunlight；The invention have the advantage that technique is simple, controllability is good, and harmony is high.

Description

A kind of In2O3/Bi2Sn2O7 composite visible light catalyst and its preparation method

technical field

The invention relates to a composite visible light catalyst and a preparation method thereof, in particular to an In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible light catalyst and a preparation method thereof.

Background technique

As the problem of environmental pollution becomes more and more serious, people are also facing a huge energy crisis, and it is extremely urgent to solve the current serious environmental pollution problem and energy shortage. Among them, semiconductor photocatalysis technology can degrade organic pollutants and reduce carbon dioxide, which has been considered an important means to solve the current environmental pollution problems. At present, materials with excellent photocatalytic performance and photoelectric conversion efficiency are mainly concentrated in wide bandgap semiconductors such as TiO ₂ , ZnO, SnO ₂ and niobate. Usually, these semiconductors have a band gap above 3eV, so they can only absorb ultraviolet light. Partly, this greatly affects the catalytic performance of photocatalytic materials. There are two main methods for research on semiconductor materials: one is to narrow the gap energy gap by doping; the other is to promote the effective separation of electron-hole pairs by preparing composite materials.

In recent years, due to the layered structure of some bismuth-based oxides and their composites (bismuth stannate) and the hybridization of Bi 6s and 02p orbitals, the valence band has moved up, so that it has a smaller band gap and valence band Discrete characteristics, which will facilitate the migration of photogenerated electrons from the valence band to the conduction band, can decompose water and effectively degrade organic pollutants under visible light, and become a class of photocatalytic materials with development potential. As a photosensitizer, In ₂ O ₃ is often used to combine with wide bandgap semiconductors to improve the visible light catalytic performance of materials.

In the application of photocatalysts, making N-type semiconductor materials into composite materials is mainly to combine two substances with matching energy bands, so as to reduce the recombination rate of electrons and holes. The materials mainly include TiO ₂ , ZnO, and ZrO. ₂ , SnO ₂ and SiO ₂ etc. Although Bi ₂ Sn ₂ O ₇ nanoparticles can absorb visible light, the recombination rate of electron and hole pairs formed by light excitation is relatively high.

Contents of the invention

The object of the present invention is to provide an In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible light catalyst prepared by using N-type semiconductor In ₂ O ₃ and N-type semiconductor Bi ₂ Sn ₂ O ₇ and a preparation method thereof.

In order to achieve the above purpose, the In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible light catalyst of the present invention consists of Bi ₂ Sn ₂ O ₇ nanoparticles with a particle size of 10-20 nm attached to a 0.1 μm cubic In ₂ O ₃ block composition.

The preparation method of the present invention is as follows:

1) Preparation of Bi ₂ Sn ₂ O ₇ precursor

Dissolve 3-5 mol of Bi(NO ₃ ) ₃ in 30-60 mL of nitric acid solution with a concentration of 1 mol/L, and stir to obtain solution A;

Dissolve 3-5 mol of K ₂ Sn ₂ O ₃ in 30-60 mL of ultrapure water at 5°C to obtain solution B;

Add solution B dropwise to solution A and stir evenly to obtain mixture C; add 1 to 3 mol/L NaOH solution dropwise to mixture C until the pH is 10 to 12, centrifuge, and wash with ultrapure water and absolute ethanol respectively, Dry at 75°C to obtain the Bi ₂ Sn ₂ O ₇ precursor;

2) Preparation of Bi ₂ Sn ₂ O ₇

Dissolve 0.2-0.6g of CTAB (cetyltrimethylammonium bromide) in 15-30mL of ultrapure water and stir well to obtain solution D; disperse the Bi ₂ Sn ₂ O ₇ precursor into solution D and stir well Finally, add 0.1-0.3mol/L NaOH dropwise until the pH is 10-12 to obtain mixture E; transfer mixture E to a 50mL polytetrafluoroethylene liner, keep it at 180°C for 24h, cool to room temperature, and use 100 ~200mL of ultrapure water and 200~400mL of absolute ethanol were washed separately, and dried at 75°C to obtain Bi ₂ Sn ₂ O ₇ ;

3) Preparation of In ₂ O ₃ /Bi ₂ Sn ₂ O ₇

Dissolve 0.1-1.4g of In(NO ₃ ) ₃ in 10-50mL of absolute ethanol, and stir evenly to obtain solution F; disperse Bi ₂ Sn ₂ O ₇ into solution F, stir for 5 hours, and heat at 80°C. The product after evaporating the solvent was placed in a muffle furnace, annealed at 400-500° C. for 3 hours, and cooled to room temperature to obtain the In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible light catalyst.

In the In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible light catalyst of the present invention, Bi ₂ Sn ₂ O ₇ nanoparticles are dispersed in the ethanol solution of In(NO ₃ ) ₃ , and then the Bi ₂ Sn ₂ O ₇ The nanoparticles are attached to the surface of the cubic In ₂ O ₃ bulk to form a composite material, and the effective separation of electrons and holes can be achieved during the photocatalytic reaction.

In photocatalyst applications, making N-type semiconductor materials into composite materials is mainly to combine two substances with matching energy bands, thereby reducing the recombination rate of electrons and holes. Although Bi ₂ Sn ₂ O ₇ nanoparticles can absorb visible light, the recombination rate of electron and hole pairs formed by light excitation is relatively high. Effective separation, the present invention is prepared by using cubic In ₂ O ₃ and Bi ₂ Sn ₂ O ₇ nanoparticles to compound, that is, using annealing method to attach Bi ₂ Sn ₂ O ₇ nanoparticles to cubic In ₂ O ₃ blocks In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible light catalyst with matching energy band structure. The matching of the energy band structure means that the valence band and conduction band position of Bi ₂ Sn ₂ O ₇ and the conduction band and valence band position of In ₂ O ₃ can form a typical type II heterojunction structure, by combining Bi ₂ Sn The ₂ O ₇ nanoparticles are attached to the cubic In ₂ O ₃ block, and an active center is formed on the contact surface of Bi ₂ Sn ₂ O ₇ and In ₂ O _3. After the Bi ₂ Sn ₂ O ₇ nanoparticles are excited by light, the conduction The electrons on the band will be transferred to the conduction band of In ₂ O ₃ , and the holes generated in the valence band of In ₂ O ₃ by light excitation will be transferred to the valence band of Bi ₂ Sn ₂ O _7. These active materials undergo different The reaction process can realize the effective degradation of pollutants in water, that is, realize the effective separation of electrons and holes, and improve the photocatalytic efficiency of semiconductor materials. In the case of ensuring that Bi ₂ Sn ₂ O ₇ still absorbs visible light, it is also a composite catalyst that can broaden the visible light absorption range and effectively separate electrons and holes.

The invention adopts the wet chemical method to prepare the In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible light catalyst, the process is simple, the controllability is good, and the coordination is high.

Description of drawings

Figure 1 is a schematic diagram of the structure of the In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible light catalyst prepared by the present invention; the scattered black spots are Bi ₂ Sn ₂ O ₇ nanoparticles, and the cubic blocks are In ₂ O ₃ .

Fig. 2 is the degradation curve of rhodamine B by 0.1In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible photocatalyst and 0.1In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ mixed photocatalyst under visible light.

detailed description

Example 1:

1) Preparation of Bi ₂ Sn ₂ O ₇ precursor

Dissolve 5 mol of Bi(NO ₃ ) ₃ in 50 mL of 1 mol/L nitric acid solution, and stir to obtain solution A;

Dissolve 5 mol of K ₂ Sn ₂ O ₃ in 50 mL of ultrapure water at 5°C to obtain solution B;

Add solution B dropwise to solution A and stir evenly to obtain mixture C; add 2mol/L NaOH solution dropwise to mixture C until the pH is 12, centrifuge, wash with ultrapure water and absolute ethanol, and dry at 75°C Dry Bi ₂ Sn ₂ O ₇ precursor;

2) Preparation of Bi ₂ Sn ₂ O ₇

Dissolve 0.5g of CTAB (cetyltrimethylammonium bromide) in 25mL of ultrapure water and stir well to obtain solution D; disperse the Bi ₂ Sn ₂ O ₇ precursor into solution D and stir well, then add dropwise 0.1mol/L NaOH to pH 10 to obtain mixture E; transfer mixture E to a 50mL polytetrafluoroethylene liner, keep at 180°C for 24h, cool to room temperature, and use 100-200mL ultrapure water and 200- Wash with 400mL absolute ethanol separately, and dry at 75°C to obtain Bi ₂ Sn ₂ O ₇ ;

3) Preparation of In ₂ O ₃ /Bi ₂ Sn ₂ O ₇

Dissolve 0.1g of In(NO ₃ ) ₃ in 10mL of absolute ethanol, stir well to obtain solution F; disperse Bi ₂ Sn ₂ O ₇ into solution F, stir for 5h, heat at 80°C, and evaporate the solvent to dryness The product was placed in a muffle furnace, annealed at 400° C. for 3 h, and cooled to room temperature to obtain an In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible photocatalyst.

It can be seen from Figure 1 that the prepared In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible light catalyst consists of Bi ₂ Sn ₂ O ₇ nanoparticles with a particle size of 10-20 nm attached to cubic In ₂ O ₃ particles of about 0.1 μm Constructed on blocks.

Comparative example 1

1) Preparation of Bi ₂ Sn ₂ O ₇

Dissolve 5mol Bi(NO ₃ ) ₃ in 50mL of 1mol/L nitric acid solution, stir for 1h, solution A; dissolve 5mol K ₂ Sn ₂ O ₃ in 50mL of ultrapure water at 5°C, solution B; Add dropwise to A to obtain mixture A; after stirring for 0.5h, add 2mol/L NaOH solution dropwise until the pH of mixture A is 12, transfer mixture A to a 50mL polytetrafluoroethylene liner, keep at 180°C for 24h, After cooling to room temperature, wash three times with 200mL ultrapure water and 200mL absolute ethanol, and dry at 75°C for 5h to obtain product B.

2) Preparation of In ₂ O ₃

Dissolve 5mmol of In(NO ₃ ) ₃ in 50mL of absolute ethanol, stir for 1h, solution C; heat at 80°C, evaporate the solvent to dryness, product C, put product C in a muffle furnace, 400-500°C Anneal 3h. After cooling down to room temperature, set aside.

3) Preparation of In ₂ O ₃ /Bi ₂ Sn ₂ O ₇

Add 0.15 g of In ₂ O ₃ and 1 g of Bi ₂ Sn ₂ O ₇ to 10 mL of ethanol to obtain mixture D; sonicate for 0.5 h, then stir for 3 h, heat at 80°C, and evaporate the solvent to obtain product E.

The product E was annealed at 400-500° C. for 3 h, and cooled down to room temperature to obtain In ₂ O ₃ -Bi ₂ Sn ₂ O ₇ mixed photocatalyst.

The photocatalytic performance of Example 1 and Comparative Example was tested, and it can be seen from Figure 2 that the comparative In ₂ O ₃ -Bi ₂ Sn ₂ O ₇ mechanical blending, In ₂ O ₃ and Bi ₂ Sn ₂ O ₇ materials, 0.1In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composites exhibited the best photocatalytic performance.

Example 2:

1) Preparation of Bi ₂ Sn ₂ O ₇ precursor

Dissolve 3 mol of Bi(NO ₃ ) ₃ in 30 mL of 1 mol/L nitric acid solution, and stir to obtain solution A;

Dissolve 4 mol of K ₂ Sn ₂ O ₃ in 40 mL of ultrapure water at 5°C to obtain solution B;

Add solution B dropwise to solution A and stir evenly to obtain mixture C; add 1mol/L NaOH solution dropwise to mixture C until the pH is 11, centrifuge, wash with ultrapure water and absolute ethanol, and dry at 75°C Dry Bi ₂ Sn ₂ O ₇ precursor;

2) Preparation of Bi ₂ Sn ₂ O ₇

Dissolve 0.3g of CTAB (cetyltrimethylammonium bromide) in 18mL ultrapure water and stir well to obtain solution D; disperse the Bi ₂ Sn ₂ O ₇ precursor into solution D and stir well, then add dropwise 0.2mol/L NaOH to pH 12 to obtain mixture E; transfer mixture E to a 50mL polytetrafluoroethylene liner, keep at 180°C for 24h, cool to room temperature, and use 100-200mL ultrapure water and 200- Wash with 400mL absolute ethanol separately, and dry at 75°C to obtain Bi ₂ Sn ₂ O ₇ ;

3) Preparation of In ₂ O ₃ /Bi ₂ Sn ₂ O ₇

Dissolve 0.5g of In(NO ₃ ) ₃ in 20mL of absolute ethanol, stir well to obtain solution F; disperse Bi ₂ Sn ₂ O ₇ into solution F, stir for 5h, heat at 80°C, and evaporate the solvent to dryness The product was placed in a muffle furnace, annealed at 450° C. for 3 h, and cooled to room temperature to obtain an In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible light catalyst.

Example 3:

1) Preparation of Bi ₂ Sn ₂ O ₇ precursor

Dissolve 4 mol of Bi(NO ₃ ) ₃ in 40 mL of 1 mol/L nitric acid solution, and stir to obtain solution A;

Dissolve 3.5 mol of K ₂ Sn ₂ O ₃ in 35 mL of ultrapure water at 5°C to obtain solution B;

Add solution B dropwise to solution A and stir evenly to obtain mixture C; add 3mol/L NaOH solution dropwise to mixture C until the pH is 10, centrifuge, wash with ultrapure water and absolute ethanol, and dry at 75°C Dry Bi ₂ Sn ₂ O ₇ precursor;

2) Preparation of Bi ₂ Sn ₂ O ₇

Dissolve 0.6g of CTAB (cetyltrimethylammonium bromide) in 30mL of ultrapure water and stir well to obtain solution D; disperse the Bi ₂ Sn ₂ O ₇ precursor into solution D and stir well, then add dropwise 0.3mol/L NaOH to pH 11 to obtain mixture E; transfer mixture E to a 50mL polytetrafluoroethylene liner, keep at 180°C for 24h, cool to room temperature, and use 100-200mL ultrapure water and 200- Wash with 400mL absolute ethanol separately, and dry at 75°C to obtain Bi ₂ Sn ₂ O ₇ ;

3) Preparation of In ₂ O ₃ /Bi ₂ Sn ₂ O ₇

Dissolve 0.8g of In(NO ₃ ) ₃ in 30mL of absolute ethanol, stir well to obtain solution F; disperse Bi ₂ Sn ₂ O ₇ into solution F, stir for 5h, heat at 80°C, and evaporate the solvent to dryness The product was placed in a muffle furnace, annealed at 500° C. for 3 h, and cooled to room temperature to obtain an In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible light catalyst.

Example 4:

1) Preparation of Bi ₂ Sn ₂ O ₇ precursor

Dissolve 3.5 mol of Bi(NO ₃ ) ₃ in 45 mL of 1 mol/L nitric acid solution, and stir to obtain solution A;

Dissolve 3 mol of K ₂ Sn ₂ O ₃ in 30 mL of ultrapure water at 5°C to obtain solution B;

Add solution B dropwise to solution A and stir evenly to obtain mixture C; add 1.5mol/L NaOH solution dropwise to mixture C until the pH is 11, then centrifuge, and wash with ultrapure water and absolute ethanol respectively, at 75°C Dry to obtain the Bi ₂ Sn ₂ O ₇ precursor;

2) Preparation of Bi ₂ Sn ₂ O ₇

Dissolve 0.2g of CTAB (cetyltrimethylammonium bromide) in 15mL of ultrapure water and stir well to obtain solution D; disperse the Bi ₂ Sn ₂ O ₇ precursor into solution D and stir well, then add dropwise 0.3mol/L NaOH to pH 10 to obtain mixture E; transfer mixture E to a 50mL polytetrafluoroethylene liner, keep at 180°C for 24h, cool to room temperature, and use 100~200mL ultrapure water and 200~ Wash with 400mL absolute ethanol separately, and dry at 75°C to obtain Bi ₂ Sn ₂ O ₇ ;

3) Preparation of In ₂ O ₃ /Bi ₂ Sn ₂ O ₇

Dissolve 1.0g of In(NO ₃ ) ₃ in 40mL of absolute ethanol, stir well to obtain solution F; disperse Bi ₂ Sn ₂ O ₇ into solution F, stir for 5h, heat at 80°C, and evaporate the solvent to dryness The product was placed in a muffle furnace, annealed at 480° C. for 3 h, and cooled to room temperature to obtain an In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible photocatalyst.

Example 5:

1) Preparation of Bi ₂ Sn ₂ O ₇ precursor

Dissolve 4.5 mol of Bi(NO ₃ ) ₃ in 60 mL of 1 mol/L nitric acid solution, and stir to obtain solution A;

Dissolve 4.5 mol of K ₂ Sn ₂ O ₃ in 60 mL of ultrapure water at 5°C to obtain solution B;

Add solution B dropwise to solution A and stir evenly to obtain mixture C; add 2.5mol/L NaOH solution dropwise to mixture C until the pH is 12, then centrifuge, wash with ultrapure water and absolute ethanol, and store at 75°C Dry to obtain the Bi ₂ Sn ₂ O ₇ precursor;

2) Preparation of Bi ₂ Sn ₂ O ₇

Dissolve 0.4g of CTAB (cetyltrimethylammonium bromide) in 20mL of ultrapure water and stir well to obtain solution D; disperse the Bi ₂ Sn ₂ O ₇ precursor into solution D and stir well, then add dropwise 0.1mol/L NaOH to pH 12 to obtain mixture E; transfer mixture E to a 50mL polytetrafluoroethylene liner, keep at 180°C for 24h, cool to room temperature, and use 100~200mL ultrapure water and 200~ Wash with 400mL absolute ethanol separately, and dry at 75°C to obtain Bi ₂ Sn ₂ O ₇ ;

3) Preparation of In ₂ O ₃ /Bi ₂ Sn ₂ O ₇

Dissolve 1.4g of In(NO ₃ ) ₃ in 50mL of absolute ethanol, stir well to obtain solution F; disperse Bi ₂ Sn ₂ O ₇ into solution F, stir for 5h, heat at 80°C, and evaporate the solvent to dryness The product was placed in a muffle furnace, annealed at 420° C. for 3 h, and cooled to room temperature to obtain an In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible light catalyst.

Claims (2)

1. An In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible light catalyst, characterized in that: Bi ₂ Sn ₂ O ₇ nanoparticles with a particle size of 10-20 nm are attached to 0.1 μm cubic In ₂ O ₃ Constructed on blocks. 2. A preparation method of In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible light catalyst, characterized in that: 1) Preparation of Bi ₂ Sn ₂ O ₇ precursor Dissolve 3-5 mol of Bi(NO ₃ ) ₃ in 30-60 mL of nitric acid solution with a concentration of 1 mol/L, and stir to obtain solution A; Dissolve 3-5 mol of K ₂ Sn ₂ O ₃ in 30-60 mL of ultrapure water at 5°C to obtain solution B; Add solution B dropwise to solution A and stir evenly to obtain mixture C; add 1 to 3 mol/L NaOH solution dropwise to mixture C until the pH is 10 to 12, centrifuge, and wash with ultrapure water and absolute ethanol respectively, Dry at 75°C to obtain the Bi ₂ Sn ₂ O ₇ precursor; 2) Preparation of Bi ₂ Sn ₂ O ₇ Dissolve 0.2-0.6g of CTAB in 15-30mL ultrapure water and stir evenly to obtain solution D; disperse the Bi ₂ Sn ₂ O ₇ precursor into solution D and stir evenly, then add 0.1-0.3mol/L NaOH dropwise The mixture E was obtained until the pH was 10-12; the mixture E was transferred to a 50mL polytetrafluoroethylene liner, kept at 180°C for 24h, cooled to room temperature, and mixed with 100-200mL ultrapure water and 200-400mL absolute ethanol Wash separately and dry at 75°C to get Bi ₂ Sn ₂ O ₇ ; 3) Preparation of In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ Dissolve 0.1-1.4g of In(NO ₃ ) ₃ in 10-50mL of absolute ethanol, and stir evenly to obtain solution F; disperse Bi ₂ Sn ₂ O ₇ into solution F, stir for 5 hours, and heat at 80°C. The product after evaporating the solvent was placed in a muffle furnace, annealed at 400-500° C. for 3 hours, and cooled to room temperature to obtain the In ₂ O ₃ /Bi ₂ Sn ₂ O ₇ composite visible light catalyst.