Preparation method and application of SrTiO3 / Bi2O3 heterojunction photocatalyst
The preparation of SrTiO3/Bi2O3 heterojunction photocatalysts by solid phase method and calcination method solves the problem of low photocarrier recombination efficiency, and achieves efficient photocatalytic water decomposition performance. The preparation method is simple and low-cost, which is suitable for large-scale production.
Patent Information
- Application Number
- CN202510181957.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-19
- Publication Date
- 2025-05-27
AI Technical Summary
The existing photocatalysts are inefficient in photogenerated carrier recombination, limiting the efficiency of water decomposition, and the process of large-scale and low-cost preparation of high-quality photocatalysts is immature.
The SrTiO3/Bi2O3 heterojunction photocatalyst was prepared by solid phase method and calcination method. By grinding SrCl2·6H2O and commercially available SrTiO3, it was compounded with Bi2O3 after calcination to form nanoparticles, achieving efficient separation of photogenerated carriers.
The overall water decomposition performance of photocatalytic is improved, and the efficient separation of photogenerated carriers is achieved. The preparation method is simple, low-cost and suitable for large-scale production.
Smart Images
Figure CN120037895A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of photocatalytic materials, and particularly relates to a preparation method and application of a SrTiO 3 / Bi 2 O 3 heterojunction photocatalyst. Background Art
[0002] Overall photocatalytic water splitting is an ideal way to obtain clean energy hydrogen. At present, the field is developing rapidly but still faces many challenges. In terms of materials, new photocatalysts are emerging continuously, such as perovskite-type, graphitic carbon nitride-based materials, etc., which have improved the light absorption range and efficiency. However, the problem of rapid recombination of photo-generated carriers has not been completely solved, which limits the water splitting efficiency. From the perspective of technical processes, by optimizing the preparation method and surface modification, the performance of photocatalysts has been enhanced to a certain extent. However, the process for large-scale and low-cost preparation of high-quality photocatalysts is still not mature. Although some laboratory results have demonstrated high water splitting efficiency, there is still a long way to go in terms of stability, cost control, etc. for industrial application.
[0003] Strontium titanate (SrTiO 3 ) is a typical perovskite-structured photocatalyst. The process of photocatalytic water splitting by it involves multiple steps such as light absorption, generation, separation and transfer of electron-hole pairs, and surface chemical reactions, and it is a popular photocatalytic water splitting material. Bismuth oxide (Bi 2 O 3 ) has a suitable energy band structure and can absorb visible light, showing certain activity in the photocatalytic water splitting reaction for hydrogen production. The present invention constructs a SrTiO 3 / Bi 2 O 3 heterojunction photocatalytic material, which can effectively inhibit the recombination of photo-generated electrons and holes, thereby improving the photocatalytic activity. There is no relevant report on the use of SrTiO 3 / Bi 2 O 3 heterojunction photocatalyst for water splitting to produce hydrogen. Summary of the Invention
[0004] In order to solve the problems of the prior art, the present invention provides a preparation method and application of a SrTiO 3 / Bi 2 O 3 heterojunction photocatalyst.
[0005] The technical solution adopted by the present invention is as follows:
[0006] A SrTiO 3 / Bi 2 O 3Preparation method of heterojunction photocatalyst, comprising the following steps:
[0007] 1) SrCl 2 ·6H 2 O and commercially available SrTiO 3 are fully ground, then spread out flat in an alumina crucible, and the crucible is placed in a high-temperature muffle furnace for calcination. After natural cooling to room temperature, it is soaked with deionized water and the product at the bottom of the crucible is scraped off. The suspension is filtered by suction and dried to obtain SrTiO 3 with high crystallinity;
[0008] 2) The SrTiO 3 with high crystallinity obtained in step 1) and Bi 2 O 3 are fully ground and then placed in a muffle furnace for calcination. After natural cooling to room temperature, the obtained product is fully ground to obtain the target product SrTiO 3 / Bi 2 O 3 nanoparticles.
[0009] Further, in the above preparation method, in step 1), the dosage of SrCl 2 ·6H 2 O is 16.5 g, and the dosage of commercially available SrTiO 3 is 1 g.
[0010] Further, in the above preparation method, in step 1), the calcination temperature is 1100 °C and the calcination time is 10 h.
[0011] Further, in the above preparation method, in step 2), the dosage of Bi 2 O 3 is 5 mg, and the dosage of SrTiO 3 with high crystallinity is 0.1 g.
[0012] Further, in the above preparation method, in step 2), the calcination temperature is 500 °C, the calcination time is 2 h, and the heating rate is 2 °C / min.
[0013] Application of the SrTiO 3 / Bi 2 O 3 heterojunction photocatalyst prepared by the preparation method described in any one of the above in photocatalytic water splitting.
[0014] Further, in the above application, the method is as follows: Under the condition of simulated sunlight irradiation, take SrTiO 3 / Bi 2 O 3 heterojunction photocatalyst and disperse it evenly in deionized water, Na3 RhCl 6 ·12H 2 O is photodeposited in the mixed solution, and then Ni(NO 3 ) 2 ·6H 2 O solution and Co(NO 3 ) 2 ·6H 2 O solution are photodeposited. Then, argon is continuously introduced into the container containing the above mixed solution at 40 mL / min to create a relatively inert environment, and water splitting is catalyzed under simulated sunlight irradiation conditions.
[0015] Furthermore, in the above application, the amount of deionized water used is 20 mL, and the concentration of the Na 3 RhCl 6 ·12H 2 O solution is 0.59 mg / mL, the amount used is 126 μL, and the photodeposition time is 10 min.
[0016] Furthermore, in the above application, the concentration of the Ni(NO 3 ) 2 ·6H 2 O solution is 7.7 mg / mL, the amount used is 10 μL, and the photodeposition time is 5 min.
[0017] Furthermore, in the above application, the concentration of the Co(NO 3 ) 2 ·6H 2 O solution is 2 mg / mL, the amount used is 21 μL, and the photodeposition time is 5 min. The beneficial effects of the present invention are as follows:
[0018] 1. The present invention prepares a SrTiO 3 / Bi 2 O 3 heterojunction photocatalyst by a solid-phase method and a calcination method, realizing efficient separation of photo-generated carriers.
[0019] 2. The SrTiO 3 / Bi 2 O 3 heterojunction photocatalyst prepared by the present invention has good overall water splitting performance in photocatalysis, and the method is simple, convenient, low-cost, mild in conditions, and conducive to large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 The SrTiO 3 catalyst prepared in Example 1 and the SrTiO 3 / Bi 2 O prepared in Example 23 X-ray diffraction pattern of the heterojunction photocatalyst.
[0021] Figure 2 SrTiO prepared for Example 1 3 catalyst and SrTiO prepared for Example 2 3 / Bi 2 O 3 Photoluminescence spectrum of the heterojunction photocatalyst.
[0022] Figure 3 SrTiO prepared for Example 1 3 catalyst and SrTiO prepared for Example 2 3 / Bi 2 O 3 Photocatalytic hydrogen evolution activity diagram of the heterojunction photocatalyst. Detailed implementation mode
[0023] Example 1
[0024] SrTiO 3 The preparation method of the catalyst is as follows:
[0025] Mix 16.5 g of SrCl 2 ·6H 2 O and 1 g of commercially available SrTiO 3 After thorough grinding, spread it evenly in an alumina crucible, and place the crucible in a high-temperature muffle furnace and calcine it at 1100 °C for 10 h. After natural cooling to room temperature, soak it with deionized water multiple times and scrape the product at the bottom of the crucible. Filter the suspension and dry it to obtain the product SrTiO with high crystallinity 3 .
[0026] Example 2
[0027] SrTiO 3 / Bi 2 O 3 The preparation method of the heterojunction photocatalyst is as follows:
[0028] Take 0.1 g of the SrTiO with high crystallinity prepared in Example 1 3 and 5 mg of Bi 2 O 3 After thorough grinding, transfer it to a muffle furnace and heat it up to 500 °C at a rate of 2 °C / min, and keep it at 500 °C for 2 h. After natural cooling to room temperature, grind the obtained product thoroughly to obtain the target product SrTiO 3 / Bi 2 O 3 nanoparticles.
[0029] Figure 1 SrTiO prepared for Example 13 The catalyst and SrTiO prepared in Example 2 3 / Bi 2 O 3 X-ray diffraction pattern of the heterojunction photocatalyst. Figure 1 In it, the characteristic diffraction peak that appears at 2θ = 27.5° corresponds to Bi 2 O 3 (1 1 1) crystal plane. The characteristic diffraction peak that appears at 2θ = 32.4° corresponds to SrTiO 3 (1 1 0) crystal plane. The peak height of the composite sample is lower than that of the original sample, indicating that the crystallinity of the composite sample decreases. The composite sample SrTiO 3 / Bi 2 O 3 Characteristic peaks of SrTiO 3 and Bi 2 O 3 can be observed in the heterojunction photocatalyst, indicating that SrTiO 3 / Bi 2 O 3 heterojunction photocatalyst is successfully prepared.
[0030] Figure 2 For SrTiO prepared in Example 1 3 and SrTiO prepared in Example 2 3 / Bi 2 O 3 Photoluminescence spectra of the heterojunction photocatalyst. As shown in the figure, the photoluminescence spectral emission peaks of the two samples at 400 nm are attributed to the recombination of carriers. In contrast, the fluorescence intensity of SrTiO 3 is significantly higher than that of SrTiO 3 / Bi 2 O 3 , indicating that the construction of the SrTiO 3 / Bi 2 O 3 heterojunction promotes carrier migration, and the increase in fluorescence lifetime indicates the improvement of carrier separation efficiency after the construction of the heterostructure.
[0031] Example 3
[0032] SrTiO 3 / Bi 2 O 3 Application of the SrTiO
[0033] 1) Under simulated sunlight irradiation and normal temperature and pressure conditions, 20 mg of SrTiO prepared in Example 2 3 / Bi 2 O 3The heterojunction photocatalyst was placed in a reactor containing a mixed solution of 20 mL of deionized water and 126 μL of Na 3 RhCl 6 ·12H 2 O (concentration 0.59 mg / mL) for photo-deposition for 10 min. Then 10 μL of Ni(NO 3 ) 2 ·6H 2 O (concentration 7.7 mg / mL) was added and photo-deposited for 5 min. Then 21 μL of Co(NO 3 ) 2 ·6H 2 O (concentration 2 mg / mL) was added and photo-deposited for 5 min. Argon was introduced into the reactor at a rate of 40 mL / min for 40 min to expel air. Under visible light irradiation, 1000 μL of gas in the reactor was sampled every 30 min, and the catalytic products collected were quantitatively analyzed using a gas chromatograph.
[0034] 2) Operate according to step 1), except that the SrTiO 3 / Bi 2 O 3 heterojunction photocatalyst was replaced with the SrTiO 3 catalyst prepared in Example 1 and commercially available Bi 2 O 3 , and other conditions remained unchanged. Their gases were respectively taken to measure the hydrogen production and oxygen production efficiency.
[0035] Figure 3 is a graph of the relationship between hydrogen content and light irradiation time. The sampled gas was measured for its peak area by a gas chromatograph, and then converted into its amount of substance by calculation. As Figure 3 shows, after 3 h, the H 3 production rate of the SrTiO 2 catalyst was 16.74 mmol / g, with low activity; Bi 2 O 3 had almost no activity; the H 3 / Bi 2 O 3 production rate of the heterojunction photocatalyst SrTiO 2 was 22.52 mmol / g, which was improved compared with the SrTiO 3 catalyst. At the same time, the stoichiometric ratio of H 2 to O 2 satisfied the relationship of 2:1. The above experimental results indicate that constructing a heterojunction structure can effectively improve the overall water splitting performance of photocatalysis.
Claims
1. A method for preparing a SrTiO3 / Bi2O3 heterojunction photocatalyst, characterized in that: The following steps are involved: 1) SrCl2·6H2O and commercially available SrTiO3 are fully ground and spread in an alumina crucible, and the crucible is placed in a high-temperature muffle furnace for calcination. After naturally cooling to room temperature, the product at the bottom of the crucible is soaked in deionized water and scraped, and the suspension is filtered and dried to obtain a product with high crystallinity of SrTiO3; 2) The high-crystallinity SrTiO3 and Bi2O3 obtained in step 1) are fully ground and then calcined in a muffle furnace. After naturally cooling to room temperature, the obtained product is fully ground to obtain the target product SrTiO3 / Bi2O3 nanoparticles.
2. The preparation method according to claim 1, characterized in that: In step 1), the amount of SrCl2·6H2O used is 16.5 g, and the amount of commercially available SrTiO3 used is 1 g.
3. The preparation method according to claim 1, characterized in that: In step 1), the calcination temperature is 1100° C. and the calcination time is 10 h.
4. The preparation method according to claim 1, characterized in that: In step 2), the amount of Bi2O3 used is 5 mg, and the amount of high-crystallinity SrTiO3 used is 0.1 g.
5. The preparation method according to claim 1, characterized in that: In step 2), the calcination temperature is 500° C., the calcination time is 2 h, and the heating rate is 2° C. / min.
6. Use of the SrTiO3 / Bi2O3 heterojunction photocatalyst prepared by the preparation method according to any one of claims 1 to 5 in photocatalytic water decomposition.
7. The use according to claim 6, characterized in that: The method is as follows: Under simulated solar light irradiation conditions, SrTiO3 / Bi2O3 heterojunction photocatalyst is uniformly dispersed in a mixed solution of deionized water and Na3RhCl6·12H2O for photodeposition, and then Ni(NO3)2·6H2O solution and Co(NO3)2·6H2O solution are sequentially injected for photodeposition, and then argon gas is continuously introduced into the container containing the above mixed solution at 40 mL / min to obtain a relatively inert environment, thereby catalyzing water decomposition under simulated solar light irradiation conditions.
8. The use according to claim 7, characterized in that: The amount of deionized water used is 20 mL, the concentration of Na3RhCl6·12H2O solution is 0.59 mg / mL, the amount used is 126 μL, and the photodeposition time is 10 min.
9. The use according to claim 7, characterized in that: The concentration of the Ni(NO3)2·6H2O solution is 7.7 mg / mL, the dosage is 10 μL, and the photodeposition time is 5 min.
10. The use according to claim 7, characterized in that: The concentration of the Co(NO3)2·6H2O solution was 2 mg / mL, the dosage was 21 μL, and the photodeposition time was 5 min.