Mo-doped SrTiO3 photocatalyst as well as preparation method and application thereof

Abstract

The invention 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, the Mo-doped SrTiO3 is prepared by adopting a molten salt medium and a high-temperature solid-phase method, then the cocatalyst is loaded by an in-situ step-by-step photodeposition method, and the Mo-doped SrTiO3 can be applied to the field of photocatalytic full water splitting. Compared with an existing photocatalyst, the Mo-doped SrTiO3 photocatalyst is high in stability, good in controllability and high in hydrogen production amount, carrier recombination is effectively inhibited, and the separation efficiency of carriers is further improved. The method is green and environment-friendly, simple, convenient to operate and low in material preparation cost, conforms to the green and environment-friendly concept advocated at present, and has a wide application market prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of photocatalytic materials, and specifically relates to a Mo-doped SrTiO3 photocatalyst and a preparation method and application thereof. Background Art

[0002] Recently, environmental issues such as global warming and renewable energy have attracted widespread attention from all over the world. Energy shortages and natural environmental pollution have gradually intensified, and the demand for renewable energy and clean energy is growing. Hydrogen, as a clean energy source, has the advantages of high energy density, easy storage, and no pollution when burned. As a promising strategy, solar-driven overall water decomposition using particulate photocatalysts to produce hydrogen energy is economically feasible, which can be an ideal substitute for fossil fuels or reduce carbon dioxide emissions. The present invention uses particulate semiconductor photocatalysts for overall water decomposition to produce solar green hydrogen, which is a potential method to solve the problems of global energy supply and environmental deterioration, and provides a green solution to future energy crisis problems.

[0003] SrTiO3 is a typical perovskite material with simple synthesis and suitable energy band structure, and can be used as an ideal material for photocatalytic water decomposition. The application of doping technology further improves its performance. Doped SrTiO3 semiconductor materials effectively improve the efficiency of photocatalytic water decomposition by reducing carrier recombination. Mo-doped SrTiO3 has excellent ultraviolet light absorption performance and stability, and accelerates the separation efficiency of photogenerated electrons and holes. The present invention constructs a Mo-doped SrTiO3 photocatalytic material, which can effectively adjust the SrTiO3 band gap structure, thereby improving the photocatalytic activity. There are no related reports on the decomposition of water by Mo-doped SrTiO3 photocatalyst. Summary of the invention

[0004] In order to solve the problems in the prior art, the present invention provides a Mo-doped SrTiO3 photocatalyst and a preparation method and application thereof.

[0005] The technical solution adopted by the present invention is:

[0006] A Mo-doped SrTiO3 photocatalyst, wherein the Mo-doped SrTiO3 photocatalyst has a doping amount of Mo of 0.2-1% of the SrTiO3 in terms of molar percentage.

[0007] The above-mentioned method for preparing a Mo-doped SrTiO3 photocatalyst comprises the following steps: Preparation of Mo-doped SrTiO3: putting commercially available SrTiO3, MoO3 and SrCl2·6H2O into a mortar, mixing and grinding, transferring to an Al2O3 crucible, annealing, filtering and drying, and obtaining a Mo-doped SrTiO3 catalyst

[0008] Furthermore, in the above preparation method, the molar ratio of SrTiO3:SrCl2·6H2O=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°C.

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

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

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

[0014] Furthermore, the above application is characterized in that the method is as follows: the Mo-doped SrTiO3 photocatalyst is uniformly dispersed in a reaction tank filled with deionized water, a catalyst promoter is in situ photodeposited, 126 μl of a Rh precursor solution with a concentration of 0.59 mg / ml and a mass percentage concentration of 0.1% is added, and 300W xenon lamp is illuminated for 10 minutes, 10 μl of a Cr precursor solution with a concentration of 7.7 mg / ml and a mass percentage concentration of 0.05% is added, and 300W xenon lamp is illuminated for 5 minutes, 21 μl of a Co precursor solution with a concentration of 10 mg / ml and a mass percentage concentration of 0.05% is added, and 300W xenon lamp is illuminated for 5 minutes, and finally irradiated for another 5 minutes, argon gas is continuously introduced into the container containing the mixed solution at 40 mL / min to obtain a relatively vacuum environment, and under visible light irradiation conditions, 1000 μL of the gas in the container is taken with a microsyringe every 30 minutes, and the sample gas composition is detected by gas chromatography separation technology to determine the gas concentration.

[0015] The beneficial effects of the present invention are:

[0016] 1. The present invention uses a molten salt medium and a high-temperature solid-phase method to prepare a Mo-doped SrTiO3 catalyst, which reduces the recombination of photogenerated electrons and holes, adjusts the energy band structure, achieves efficient separation of photogenerated carriers, and improves photocatalytic activity.

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

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

[0019] 4. The Rh precursor solution, Cr precursor solution and Co precursor solution of the present invention are loaded on Mo-doped SrTiO3 as co-catalysts, which can add additional reaction sites on different crystal planes of the catalyst and improve the separation efficiency of photogenerated carriers. BRIEF DESCRIPTION OF THE DRAWINGS

[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 This is the hydrogen and oxygen rate diagram of the 0.5% Mo-SrTiO3 photocatalyst prepared in Example 3.

[0022] Figure 3 The hydrogen evolution activities 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 are compared. DETAILED DESCRIPTION

[0023] Example 1

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

[0025] Weigh 14.5g SrCl2·6H2O and 1g commercially available SrTiO3 in a mortar and grind for 10min to mix them evenly. Then put them in an Al2O3 crucible and calcine them at 1100℃ in a muffle furnace for 10h. Filter them with suction and then dry them in an oven at 60℃ for 12h to obtain a SrTiO3 catalyst.

[0026] Example 2

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

[0028] Weigh 14.5g SrCl2·6H2O, 1g commercially available SrTiO3 and 0.00144g MoO3 in a mortar and grind for 10 minutes to mix them evenly. Then put them in an Al2O3 crucible and calcine them at 1100°C in a muffle furnace for 10 hours. Filter them with suction and then dry them in an oven at 60°C 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 in a mortar and grind for 10min to mix them evenly. Then put them in an Al2O3 crucible and calcine them at 1100℃ in a muffle furnace for 10h. Filter them with suction and then dry them in an oven at 60℃ for 12h to obtain a 0.5% Mo-SrTiO3 catalyst.

[0032] Example 4

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

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

[0035] Example 5

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

[0037] 1) Under normal temperature and pressure conditions, the 20 mg SrTiO3 photocatalyst is uniformly dispersed in a reaction tank filled with deionized water, a catalyst promoter is in situ photodeposited, 126 μl of a Rh precursor solution with a concentration of 0.59 mg / ml and a mass percentage concentration of 0.1% is added, and 300 W xenon lamp is used for 10 min of illumination, 10 μl of a Cr precursor solution with a concentration of 7.7 mg / ml and a mass percentage concentration of 0.05% is added, and 300 W xenon lamp is used for 5 min of illumination, 21 μl of a Co precursor solution with a concentration of 10 mg / ml and a mass percentage concentration of 0.05% is added, and 300 W xenon lamp is used for 5 min of illumination, and finally irradiated for another 5 min, argon gas is continuously introduced into the container containing the mixed solution at 40 mL / min to obtain a relatively vacuum environment, and 1000 μL of the gas in the container is taken with a microsyringe every 30 min under visible light irradiation conditions, and the collected catalytic products are quantitatively analyzed using a gas chromatograph.

[0038] 2) Follow the steps of step 1), except that the SrTiO3 photocatalyst prepared in Example 1 is replaced by 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. 3， Keeping other conditions unchanged, the gases were taken separately to measure the hydrogen and oxygen production efficiencies.

[0039] Figure 2 The hydrogen and oxygen evolution rate diagram of the 0.5% Mo-SrTiO3 photocatalyst prepared in Example 3. The results show that the maximum hydrogen evolution rate of 0.5% Mo-SrTiO3 within 3 hours is 35.67mmol / g, the maximum oxygen evolution rate is 17.49mmol / g, and the rate ratio of hydrogen to oxygen is about 2:1, which is 2.3 times the hydrogen evolution rate of SrTiO3 (15.47mmol / g). This shows that Mo-doped SrTiO3 improves the separation efficiency of semiconductor photogenerated carriers, which is beneficial to improve the photocatalytic water splitting activity.

[0040] Figure 3 SrTiO3, 0.2% Mo-SrTiO prepared in Example 1, Example 2, Example 3, Example 4 and Example 5 3、 Comparison of the activity of 0.5% Mo-SrTiO3 and 1% Mo-SrTiO3 photocatalysts for hydrogen evolution in water decomposition. Figure 3 It can be seen that after 1 hour of light reaction, the H2 production of SrTiO3 is 5.48mmol / g / h, the H2 production of 0.2% Mo-SrTiO3 is 8.54mmol / g / h, the H2 production of 0.5% Mo-SrTiO3 is 12.89mmol / g / h, and the H2 production of 1% Mo-SrTiO3 is 9.59mmol / g / h. The catalytic hydrogen production performance of Mo-doped SrTiO3 photocatalyst is greatly improved compared with pure SrTiO3. This shows that after Mo doping, the photogenerated electron transmission and transfer ability is stronger, and the electron holes have a stronger redox ability.

Claims

1. A Mo-doped SrTiO3 photocatalyst, characterized in that: The Mo-doped SrTiO3 photocatalyst has a doping amount of Mo of 0.2-1% of SrTiO3 in terms of molar percentage.

2. The method for preparing a Mo-doped SrTiO3 photocatalyst according to claim 1, characterized in that: The preparation method comprises the following steps: Preparation of Mo-doped SrTiO3: SrTiO3, MoO3 and SrCl2·6H2O are mixed and ground in a mortar, then transferred to an Al2O3 crucible, calcined in a muffle furnace, filtered and dried to obtain a Mo-doped SrTiO3 catalyst.

3. The preparation method according to claim 2, characterized in that: In step 1), the molar ratio of SrTiO3:SrCl2·6H2O=1:

10.

4. The preparation method according to claim 2, characterized in that: The grinding time is 10 min.

5. The preparation method according to claim 2, characterized in that: The calcination temperature is 1100°C.

6. The preparation method according to claim 2, characterized in that: The calcination time is 10 hours.

7. The preparation method according to claim 2, characterized in that: The drying temperature is 60° C. and the drying time is 12 hours.

8. Use of the Mo-doped SrTiO3 photocatalyst according to claim 1 in catalytic degradation of water under visible light irradiation.

9. The use according to claim 8, characterized in that: The method is as follows: Mo-doped SrTiO3 photocatalyst is uniformly dispersed in a reaction tank filled with deionized water, a co-catalyst is in situ photodeposited, 126 μl of a Rh precursor solution with a concentration of 0.59 mg / ml and a mass percentage concentration of 0.1% is added, and 300 W xenon lamp is illuminated for 10 minutes, 10 μl of a Cr precursor solution with a concentration of 7.7 mg / ml and a mass percentage concentration of 0.05% is added, and 300 W xenon lamp is illuminated for 5 minutes, 21 μl of a Co precursor solution with a concentration of 10 mg / ml and a mass percentage concentration of 0.05% is added, and 300 W xenon lamp is illuminated for 5 minutes, and finally irradiated for another 5 minutes, argon gas is continuously introduced into the container containing the mixed solution at 40 mL / min to obtain a relatively vacuum environment, and water is decomposed to release hydrogen under visible light irradiation conditions.

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