Mo-doped SrTiO3 photocatalyst, and preparation method and application thereof

Abstract

The application relates to a Mo-doped SrTiO3 photocatalyst as well as a preparation method and application thereof, and belongs to the technical field of photocatalytic materials. In the experiment process, a molten salt medium is adopted, a Mo-doped SrTiO3 is prepared by a high-temperature solid phase method, and then a cocatalyst is loaded by an in-situ step-by-step photodeposition method, which can be applied to the field of photocatalytic overall water splitting. Compared with existing photocatalysts, the Mo-doped SrTiO3 photocatalyst has the advantages of high stability, good controllability, high hydrogen production, effective inhibition of carrier recombination and further improvement of the separation efficiency of carriers. The application is green and environment-friendly, simple in method, convenient in operation, low in material preparation cost, conforms to the current advocated green and environment-friendly concept, and has a wide application market prospect.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic materials technology, specifically relating to a Mo-doped SrTiO3 photocatalyst, its preparation method, and its application. Background Technology

[0002] Recently, environmental issues such as global warming and renewable energy have attracted widespread attention worldwide. Energy shortages and environmental pollution are gradually worsening, leading to a growing demand for renewable and clean energy sources. Hydrogen, as a clean energy source, boasts advantages such as high energy density, ease of storage, and no pollution during combustion. As a promising strategy, solar-driven monolithic water splitting using particulate photocatalysts to produce hydrogen is economically feasible and could be an ideal alternative to fossil fuels or reduce carbon dioxide emissions. This invention utilizes a particulate semiconductor photocatalyst for monolithic water splitting, a solar-powered green hydrogen production method that offers a potential solution to global energy supply and environmental degradation problems, providing a green solution to future energy crises.

[0003] SrTiO3 is a typical perovskite material, simple to synthesize, and with a suitable band structure, making it an ideal material for photocatalytic water splitting. The application of doping technology further enhances its performance. Doped SrTiO3 semiconductor materials effectively improve the efficiency of photocatalytic water splitting by reducing carrier recombination. Mo-doped SrTiO3 exhibits excellent ultraviolet light absorption performance and stability, accelerating the separation efficiency of photogenerated electrons and holes. This invention constructs a Mo-doped SrTiO3 photocatalytic material that can effectively adjust the band gap structure of SrTiO3, thereby improving photocatalytic activity. There are currently no reports on Mo-doped SrTiO3 photocatalysts for water splitting. Summary of the Invention

[0004] To address the problems in the prior art, this invention provides a Mo-doped SrTiO3 photocatalyst, its preparation method, and its application.

[0005] The technical solution adopted in this invention is as follows:

[0006] A Mo-doped SrTiO3 photocatalyst, wherein the Mo doping amount is 0.2-1% of SrTiO3 by molar percentage.

[0007] The above-mentioned method for preparing Mo-doped SrTiO3 photocatalyst includes the following steps: Preparation of Mo-doped SrTiO3: Commercially available SrTiO3, MoO3, and SrCl2·6H2O are mixed and ground in a mortar, then transferred to an Al2O3 crucible, annealed, filtered, and dried to obtain the Mo-doped SrTiO3 catalyst.

[0008] Furthermore, in the above preparation method, the molar ratio of SrTiO3:SrCl2·6H2O is 1:10.

[0009] Furthermore, in the above preparation method, the grinding time is 10 minutes.

[0010] Furthermore, in the above preparation method, the calcination temperature is 1100℃.

[0011] Furthermore, in the above preparation method, the calcination time is 10 hours.

[0012] Furthermore, in the above preparation method, the drying temperature is 60°C and the drying time is 12 hours.

[0013] Application of the above-mentioned Mo-doped SrTiO3 photocatalyst in the catalytic total water splitting under visible light irradiation

[0014] Furthermore, the above application is characterized by the following method: Mo-doped SrTiO3 photocatalyst is uniformly dispersed in a reaction vessel containing deionized water. An in-situ photocatalyst is deposited. 126 μl of a 0.59 mg / ml Rh precursor solution (mass percentage concentration 0.1%) is added, and the mixture is irradiated with a 300W xenon lamp for 10 min. Then, 10 μl of a 7.7 mg / ml Cr precursor solution (mass percentage concentration 0.05%) is added, and the mixture is irradiated with a 300W xenon lamp for 5 min. Next, 21 μl of a 10 mg / ml Co precursor solution (mass percentage concentration 0.05%) is added, and the mixture is irradiated with a 300W xenon lamp for 5 min. Finally, the mixture is irradiated for another 5 min. Argon gas is continuously introduced into the container containing the mixed solution at a rate of 40 mL / min to create a relative vacuum environment. Under visible light irradiation, 1000 μL of gas is taken from the container every 30 min using a microsyringe. The gas composition and concentration of the sample gas are determined using gas chromatography separation technology.

[0015] The beneficial effects of this invention are as follows:

[0016] 1. This invention utilizes a molten salt medium and a high-temperature solid-state method to prepare Mo-doped SrTiO3 catalysts, thereby reducing the recombination of photogenerated electrons and holes, adjusting the band structure, achieving efficient separation of photogenerated carriers, and improving photocatalytic activity.

[0017] 2. The Mo-doped SrTiO3 catalyst prepared by this invention has excellent ultraviolet light absorption performance and stability, which is an effective way to improve visible light photocatalysis.

[0018] 3. The Mo-doped SrTiO3 photocatalyst prepared by this invention has good photocatalytic water splitting performance, and the method is simple, convenient, low-cost, mild, and conducive to large-scale production.

[0019] 4. In this invention, the Rh precursor solution, Cr precursor solution, and Co precursor solution are used as co-catalysts supported on Mo-doped SrTiO3. This can increase additional reaction sites on different crystal planes of the catalyst, thereby improving the separation efficiency of photogenerated carriers. Attached Figure Description

[0020] Figure 1 X-ray diffraction patterns of the SrTiO3 catalyst prepared in Example 1, the 0.2% Mo-SrTiO3 catalyst prepared in Example 2, the 0.5% Mo-SrTiO3 photocatalyst prepared in Example 3, and the 1% Mo-SrTiO3 catalyst prepared in Example 4.

[0021] Figure 2 Hydrogen and oxygen rates for the 0.5% Mo-SrTiO3 photocatalyst prepared in Example 3.

[0022] Figure 3 Comparison of hydrogen evolution activity of the SrTiO3 catalyst prepared in Example 1, the 0.2% Mo-SrTiO3 catalyst prepared in Example 2, the 0.5% Mo-SrTiO3 photocatalyst prepared in Example 3, and the 1% Mo-SrTiO3 catalyst prepared in Example 4. Detailed Implementation

[0023] Example 1

[0024] The preparation method of SrTiO3 catalyst is as follows:

[0025] Weigh 14.5g of SrCl2·6H2O and 1g of commercially available SrTiO3 and place them in a mortar. Grind them for 10 minutes to make them evenly mixed. Then place them in an Al2O3 crucible and calcine them in a muffle furnace at 1100℃ for 10 hours. Filter the mixture and then dry it in an oven at 60℃ for 12 hours to obtain the SrTiO3 catalyst.

[0026] Example 2

[0027] The preparation method of 0.2% Mo-SrTiO3 catalyst is as follows:

[0028] Weigh 14.5g of SrCl2·6H2O, 1g of commercially available SrTiO3 and 0.00144g of MoO3 and place them in a mortar. Grind for 10 minutes to mix them evenly. Then place them in an Al2O3 crucible and calcine them in a muffle furnace at 1100℃ for 10 hours. Filter the mixture and then dry it in an oven at 60℃ for 12 hours to obtain a 0.2% Mo-SrTiO3 catalyst.

[0029] Example 3

[0030] The preparation method of 0.5% Mo-SrTiO3 catalyst is as follows:

[0031] Weigh 14.5g SrCl2·6H2O, 1g commercially available SrTiO3 and 0.00359g MoO3 and place them in a mortar. Grind for 10min to make them evenly mixed. Then place them in an Al2O3 crucible and calcine at 1100℃ in a muffle furnace for 10h. Filter and then dry in an oven at 60℃ for 12h to obtain 0.5% Mo-SrTiO3 catalyst.

[0032] Example 4

[0033] The preparation method of 1% Mo-SrTiO3 catalyst is as follows:

[0034] Weigh 14.5g of SrCl2·6H2O, 1g of commercially available SrTiO3 and 0.0072g of MoO3 and place them in a mortar. Grind for 10 minutes to mix them evenly. Then place them in an Al2O3 crucible and calcine them in a muffle furnace at 1100℃ for 10 hours. Filter the mixture and then dry it in an oven at 60℃ for 12 hours to obtain a 1% Mo-SrTiO3 catalyst.

[0035] Example 5

[0036] Application of Mo-SrTiO3 catalyst photocatalyst in the complete water splitting under light irradiation:

[0037] 1) Under normal temperature and pressure conditions, 20 mg of SrTiO3 photocatalyst was uniformly dispersed in a reaction vessel containing deionized water. In-situ photodeposition of the co-catalyst was performed. 126 μl of a 0.59 mg / ml Rh precursor solution (mass percentage concentration 0.1%) was added, and the mixture was irradiated with a 300 W xenon lamp for 10 min. Then, 10 μl of a 7.7 mg / ml Cr precursor solution (mass percentage concentration 0.05%) was added, and the mixture was irradiated with a 300 W xenon lamp for 5 min. Next, 21 μl of a 10 mg / ml Co precursor solution (mass percentage concentration 0.05%) was added, and the mixture was irradiated with a 300 W xenon lamp for 5 min. Finally, the mixture was irradiated for another 5 min. Argon gas was continuously introduced into the container containing the mixed solution at a rate of 40 mL / min to create a relative vacuum environment. Under visible light irradiation, 1000 μL of gas was collected from the container every 30 min using a microsyringe, and the collected catalytic products were quantitatively analyzed using a gas chromatograph.

[0038] 2) Follow the procedure in step 1), except that the SrTiO3 photocatalyst prepared in Example 1 is replaced with the 0.2% Mo-SrTiO3 catalyst prepared in Example 2, the 0.5% Mo-SrTiO3 catalyst prepared in Example 3, and the 1% Mo-SrTiO3 catalyst prepared in Example 4, respectively. 3， With all other conditions unchanged, the gases were taken separately, and the efficiency of hydrogen and oxygen production was measured.

[0039] Figure 2 The graph shows the hydrogen and oxygen evolution rates of the 0.5% Mo-SrTiO3 photocatalyst prepared in Example 3. The results show that within 3 hours, the highest hydrogen evolution rate of 0.5% Mo-SrTiO3 was 35.67 mmol / g, and the highest oxygen evolution rate was 17.49 mmol / g, with a hydrogen to oxygen rate ratio of approximately 2:1, which is 2.3 times that of SrTiO3 (15.47 mmol / g). This indicates that Mo-doping of SrTiO3 improves the separation efficiency of photogenerated carriers in the semiconductor, which is beneficial for improving the photocatalytic water splitting activity.

[0040] Figure 3 SrTiO3 and 0.2% Mo-SrTiO3 prepared in Examples 1, 2, 3, 4 and 5 3、 Comparison of the photocatalytic activity of 0.5% Mo-SrTiO3 and 1% Mo-SrTiO3 in water splitting and hydrogen evolution. Figure 3 As can be seen, after 1 hour of photocatalysis, the H2 production of SrTiO3 was 5.48 mmol / g / h, that of 0.2% Mo-SrTiO3 was 8.54 mmol / g / h, that of 0.5% Mo-SrTiO3 was 12.89 mmol / g / h, and that of 1% Mo-SrTiO3 was 9.59 mmol / g / h. The catalytic hydrogen production performance of Mo-doped SrTiO3 photocatalysts was significantly improved compared to pure SrTiO3. This indicates that Mo doping enhances the photogenerated electron transport and transfer capabilities, and the electron-hole redox capabilities are stronger.

Claims

1. The application of a Mo-doped SrTiO3 photocatalyst in the catalytic total water splitting under visible light irradiation, characterized in that, The method is as follows: Mo-doped SrTiO3 photocatalyst is uniformly dispersed in a reaction vessel containing deionized water. A co-catalyst is deposited in situ. 126 μl of a 0.59 mg / ml Rh precursor solution (mass percentage concentration 0.1%) is added, and the mixture is irradiated with a 300 W xenon lamp for 10 min. Then, 10 μl of a 7.7 mg / ml Cr precursor solution (mass percentage concentration 0.05%) is added, and the mixture is irradiated with a 300 W xenon lamp for 5 min. Finally, the mixture is irradiated with a 10 mg / ml Co precursor solution (mass percentage concentration 0.05%), and the mixture is irradiated with a 300 W xenon lamp for 5 min. The mixture is then irradiated for another 5 min. Argon gas is continuously introduced into the container containing the mixed solution at a rate of 40 mL / min to create a relative vacuum environment. Under visible light irradiation, water is decomposed to produce hydrogen. The Mo-doped SrTiO3 photocatalyst has a Mo doping amount of 0.5% of SrTiO3 by molar percentage. The preparation method of the Mo-doped SrTiO3 photocatalyst includes the following steps: SrTiO3, MoO3 and SrCl2·6H2O are mixed and ground in a mortar for 10 min, then transferred to an Al2O3 crucible, calcined in a muffle furnace at 1100℃ for 10 h, filtered and dried at 60℃ for 12 h to obtain the Mo-doped SrTiO3 catalyst. The molar ratio of SrTiO3:SrCl2·6H2O is 1:10.

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