Ni, co bimetallic alloy-strontium titanate composite photocatalyst, preparation method and application thereof
By preparing a Ni, Co bimetallic alloy-strontium titanate composite photocatalyst, the problem of strontium titanate photocatalyst dependence on precious metals was solved, and efficient and stable photocatalytic water splitting to produce hydrogen was achieved, providing an economical new photocatalyst solution.
Patent Information
- Application Number
- CN202410967741.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-18
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2044-07-18
AI Technical Summary
Existing strontium titanate photocatalysts require precious metal co-catalysts, resulting in high costs and limiting the application of solar photocatalytic water splitting to produce hydrogen.
A Ni, Co bimetallic alloy-strontium titanate composite photocatalyst was prepared by reducing Al-doped strontium titanate and a metal-organic framework containing Ni, Co bimetals under an ammonia atmosphere. The Ni, Co bimetallic alloy was loaded onto the surface of Al-doped strontium titanate to form an economical and efficient photocatalyst.
A high-efficiency photocatalytic hydrogen production from water splitting was achieved, with a photocatalytic hydrogen production rate of 979.9 μmol g⁻¹ h⁻¹, a quantum efficiency of 11.9%, and good stability.
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Figure CN118904346B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of hydrogen energy production technology, and relates to photocatalytic clean preparation technology of hydrogen energy, specifically to a Ni,Co bimetallic alloy-strontium titanate composite photocatalyst, its preparation method and application. Background Technology
[0002] Societal development largely depends on the development and utilization of energy. However, with the continuous advancement of industrialization, the environmental pollution and energy shortages caused by the massive consumption of fossil fuels have gradually attracted attention. Therefore, developing clean and efficient renewable energy sources is of great significance to the sustainable development of human society. H2, with its high energy density, ease of storage and transportation, and zero carbon emissions, has become the most ideal secondary energy source. Utilizing abundant solar energy to drive H2 production is a technology with great development potential. Using solar energy to drive photocatalytic water splitting to produce hydrogen is one of the most ideal and simplest methods for solar-hydrogen energy conversion. The key to this technology lies in the development and utilization of an economical, efficient, and stable photocatalyst system.
[0003] The principle of photocatalytic water splitting to produce hydrogen is as follows: under irradiation with light of a certain energy, a semiconductor photocatalyst is excited to generate electron-hole pairs. Electrons migrate to the catalyst surface to reduce water to hydrogen, while holes migrate to the catalyst surface to oxidize water to oxygen. According to existing research, strontium titanate is a highly promising photocatalyst; however, its excellent photocatalytic performance depends on noble metal co-catalysts, which severely limits the application of solar photocatalytic water splitting to produce hydrogen. Therefore, developing economical, efficient, and stable non-noble metal co-catalyst systems is of great significance. Summary of the Invention
[0004] The purpose of this invention is to provide a Ni,Co bimetallic alloy-strontium titanate composite photocatalyst, its preparation method, and its application, so as to achieve economical and efficient photocatalytic hydrogen production.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] A method for preparing a Ni,Co bimetallic alloy-strontium titanate composite photocatalyst includes the following steps:
[0007] Al-doped strontium titanate and a metal-organic framework containing Ni and Co bimetals were mixed evenly and then reduced under an ammonia atmosphere to obtain a Ni,Co bimetallic alloy-strontium titanate composite photocatalyst.
[0008] Furthermore, Al-doped strontium titanate was prepared via a hydrothermal method and molten salt.
[0009] Furthermore, in the metal-organic framework containing Ni,Co bimetals, the molar ratio of Ni to Co is 1:0.1-1.
[0010] Furthermore, the mass ratio of Al-doped strontium titanate to the metal-organic framework containing Ni,Co bimetals is 100 mg: 1-10 mg.
[0011] Furthermore, uniform mixing is achieved by grinding or by dispersing Al-doped strontium titanate and a metal-organic framework containing Ni and Co bimetals in a solvent and then evaporating to dryness.
[0012] Furthermore, the ammonia flow rate is 20-100 mL / min.
[0013] Furthermore, the reduction reaction is carried out at a temperature of 600-1000℃ for 1-5 hours.
[0014] Furthermore, the temperature is increased to 600-1000℃ at a heating rate of 5-10℃ / min.
[0015] A Ni,Co bimetallic alloy-strontium titanate composite photocatalyst prepared according to the method described above.
[0016] Application of a Ni,Co bimetallic alloy-strontium titanate composite photocatalyst prepared according to the method in photocatalytic hydrogen production.
[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0018] This invention provides a novel catalyst preparation method that utilizes a NiCo-MOF (NiCo-Metal-Organic Framework) containing Ni and Co bimetals as a precursor to prepare a NiCo alloy cocatalyst. The NiCo bimetallic alloy is then supported on the surface of Al-doped strontium titanate, achieving both the generation and loading of the alloy cocatalyst in one step. The raw materials are inexpensive and readily available, and the preparation method is simple and easily reproducible, overcoming the high cost associated with the use of precious metals in existing technologies. The Ni,Co bimetallic alloy-strontium titanate composite photocatalyst prepared by this invention exhibits excellent photocatalytic performance in the complete splitting of water to produce hydrogen and oxygen. The photocatalytic hydrogen production rate reaches 979.9 μmol / g. -1 h -1 The quantum efficiency at 350 nm is 11.9%, and it exhibits good stability in photocatalytic hydrogen production. This invention is simple to operate, has good reproducibility, and provides a reliable solution for the development and application of economical, efficient, and stable novel photocatalysts. Attached Figure Description
[0019] Figure 1 These are X-ray diffraction (XRD) patterns of NiCo bimetallic alloy (MOF-NH3), Al-doped strontium titanate (STO), and Al-doped strontium titanate (3%-MOF-STO-NH3) loaded with NiCo bimetallic alloy.
[0020] Figure 2 These are scanning electron microscope (SEM) and transmission electron microscope (TEM) images of 3%-MOF-STO-NH3 in Example 2; where a) is SEM and b) is TEM.
[0021] Figure 3 The graph shows the photocatalytic hydrogen production rate of Al-doped strontium titanate loaded with different proportions of NiCo bimetallic alloy.
[0022] Figure 4 This is a stability test diagram of photocatalytic hydrogen production using 3%-MOF-STO-NH3 in Example 2. Detailed Implementation
[0023] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.
[0024] This invention utilizes solar energy to achieve a low-cost hydrogen production technology through photocatalytic water splitting. Specifically, it employs a reliable preparation scheme for a Ni,Co bimetallic alloy-strontium titanate composite photocatalyst to achieve complete photocatalytic water splitting to produce hydrogen and oxygen, which is beneficial for the industrial application of photocatalytic water splitting for hydrogen production.
[0025] The present invention discloses a method for preparing a Ni,Co bimetallic alloy-strontium titanate composite photocatalyst as follows: Cobalt nitrate, nickel nitrate, polyvinylpyrrolidone, and trimesic acid are dispersed in a mixed solution of H2O, ethanol, and N,N-dimethylformamide. After hydrothermal reaction, the product is washed, centrifuged, and dried to obtain a metal-organic framework (NiCo-MOF) containing Ni,Co bimetals. Al-doped strontium titanate is then prepared using conventional hydrothermal and molten salt treatment methods. Specifically, the above-mentioned metal-organic framework and strontium titanate are dispersed in an ethanol solution and stirred and evaporated to dryness in an oil bath. The obtained sample is then calcined in an ammonia atmosphere to obtain the Ni,Co bimetallic alloy-strontium titanate composite photocatalyst.
[0026] Specifically, the preparation method includes the following steps:
[0027] Step 1: Add 10 mmol of titanate butyric acid and 20 mL of ethylene glycol to the hydrothermal reactor. Add 20 mL of water and 10 mmol of strontium nitrate to a beaker and sonicate to dissolve. Drop the solution from the beaker into the hydrothermal reactor; once a gel forms, pour the entire solution in and turn the stirrer to maximum. Then add 10 mL of sodium hydroxide solution (5 mol / L) to the hydrothermal reactor and stir at 1000 rpm for 30 min. After stirring, tighten the hydrothermal reactor and place it in an oven. Heat at 200℃ for 24 h. After heating, allow it to cool naturally to room temperature in a ventilated area. Remove the sample and wash it with deionized water until the pH reaches approximately 7. Place the washed sample in a forced-air drying oven and dry at 60℃ for 12 h.
[0028] Step 2: Mix the strontium titanate, SrCl2, and Al2O3 obtained in Step 1 at a molar ratio of 1:10:0.02 and grind them in a mortar. Place the mixed material in a crucible and heat it in a muffle furnace to 1100℃ at a heating rate of 5℃ per minute, hold for 5 hours, and then allow it to cool naturally to room temperature. Dissolve the extracted sample in 50 mL of deionized water using ultrasonication, wash five times by centrifugation, and then dry the cleaned sample in a drying oven at 60℃ for 12 hours. Name the Al-doped SrTiO3 treated with the molten salt STO.
[0029] Step 3: Prepare a mixed solution with a volume ratio of H₂O:N,N-dimethylformamide:ethanol of 1-2:1-3:1-2. Dissolve 0.216 g of nickel salt (Ni(NO₃)₂·6H₂O, nickel chloride or nickel sulfate), 0.216 g of cobalt salt (Co(NO₃)₂·6H₂O, cobalt chloride or cobalt sulfate), trimesic acid, and polyvinylpyrrolidone (molecular weight 8000-700000) in the above mixed solution. When the mass of nickel salt is 0.216 g, the volume of the mixed solution is 30 mL. Sonicate at room temperature for 30 min, then transfer the solution to a 50 mL polytetrafluoroethylene hydrothermal reactor. Place the hydrothermal reactor in an oven and heat at 150 °C for 10 h, then allow it to cool naturally to room temperature. Wash the prepared sample, centrifuge and dry to obtain a metal-organic framework containing Ni,Co bimetals, and name the sample NiCo-MOF. The molar ratio of nickel salt to cobalt salt is 1:0.1-1, and the mass ratio of trimesic acid to polyvinylpyrrolidone is 1:1-12. The molar ratio of nickel salt to trimesic acid is 1:1.
[0030] In this invention, Ni(NO3)2·6H2O is used as an example of nickel salt, but nickel chloride or nickel sulfate can also be used.
[0031] In this invention, Co(NO3)2·6H2O is used as an example of cobalt salt, but cobalt chloride or cobalt sulfate can also be used.
[0032] Step 4: Disperse 100 mg STO and 1-10 mg NiCo-MOF in 5-10 mL of ethanol (water or methanol) to obtain a suspension. Place the suspension in a glass test tube and evaporate it to dryness using a constant-temperature oil bath at 80°C. Alternatively, thoroughly grind and mix 100 mg STO and 1-10 mg NiCo-MOF. Place the sample in a tube furnace filled with ammonia for high-temperature reduction. The specific experimental parameters are: NH3 flow rate 20-100 mL / min, heating rate 5-10°C / min, heating temperature 600-1000°C, and heating time 1-5 h.
[0033] Step 5: Add the Ni,Co bimetallic alloy-strontium titanate composite photocatalyst prepared in Step 4 to pure water for photocatalytic water splitting to produce hydrogen. The specific steps are as follows:
[0034] 1) Add 10 mg of Ni,Co bimetallic alloy-strontium titanate composite photocatalyst to a reactor with a volume of 105 mL, and add 80 mL of deionized water.
[0035] 2) Before illumination, purge the reactor with argon gas for 15 minutes to remove oxygen from the system;
[0036] 3) Turn on the magnetic stirrer and the xenon lamp.
[0037] This invention, for the first time, utilizes a NiCo-containing bimetallic metal-organic framework (NiCo-MOF) as a precursor to load a NiCo alloy cocatalyst onto the surface of Al-doped strontium titanate, thereby achieving the preparation of a bimetallic alloy. The bimetallic alloy is then used as a cocatalyst on the strontium titanate surface. The prepared NiCo alloy-loaded strontium titanate can completely split water and exhibits excellent photocatalytic hydrogen production activity, with a photocatalytic hydrogen production rate reaching 979.9 μmol / g. -1 h -1 The quantum efficiency at 350 nm is 11.9%, and it exhibits good stability in photocatalytic hydrogen production. This invention is simple to operate, has good reproducibility, and provides a reliable solution for the development and application of economical, efficient, and stable novel photocatalysts.
[0038] The following are specific examples.
[0039] Comparative Example 1
[0040] Step 1: Add 10 mmol of titanate butyric acid and 20 mL of ethylene glycol to the hydrothermal reactor. Add 20 mL of water and 10 mmol of strontium nitrate to a beaker and sonicate to dissolve. Drop the solution from the beaker into the hydrothermal reactor, and once a gel forms, pour the entire solution in. Turn the stirrer to maximum. Then add 10 mL of sodium hydroxide solution (5 mol / L) to the hydrothermal reactor and stir at 1000 rpm for 30 min. After stirring, tighten the hydrothermal reactor and place it in an oven. Heat at 200℃ for 24 h. After heating, allow it to cool naturally to room temperature in a ventilated area. Remove the sample and wash it with deionized water until the pH reaches approximately 7. Place the washed sample in a forced-air drying oven and dry at 60℃ for 12 h to obtain strontium titanate.
[0041] Step 2: Mix the strontium titanate, SrCl2, and Al2O3 obtained in Step 1 at a molar ratio of 1:10:0.02 and grind them in a mortar. Place the mixed material in a crucible and heat it in a muffle furnace to 1100℃ at a heating rate of 5℃ per minute, hold for 5 hours, and then allow it to cool naturally to room temperature. Dissolve the sample in 50 mL of deionized water using ultrasonication, centrifuge and wash five times, and then dry the cleaned sample in a drying oven at 60℃ for 12 hours to obtain Al-doped SrTiO3. The Al-doped SrTiO3 treated with molten salt is named STO.
[0042] Step 3: Add the STO prepared in Step 2 to pure water for photocatalytic water splitting to produce hydrogen. The specific steps are as follows:
[0043] 1) Add 10 mg of STO photocatalyst to a reactor with a volume of 105 mL, and add 80 mL of deionized water.
[0044] 2) Before illumination, purge the reactor with argon gas for 15 minutes to remove oxygen from the system;
[0045] 3) Turn on the magnetic stirrer and the xenon lamp.
[0046] Comparative Example 2
[0047] Step 1: Prepare a solution with a volume ratio of H₂O:N,N-dimethylformamide:ethanol of 1:1:1. Dissolve 0.216g Ni(NO₃)₂·6H₂O, 0.216g Co(NO₃)₂·6H₂O, 0.15g trimesic acid, and 1.5g polyvinylpyrrolidone in 30mL of the above solution. Sonicate at room temperature for 30min, then transfer the solution to a 50mL polytetrafluoroethylene hydrothermal reactor. Place the reactor in an oven and heat at 150℃ for 10h, then allow it to cool naturally to room temperature. Wash the prepared sample, centrifuge and dry it, and name the sample NiCo-MOF.
[0048] Step 2: The above sample was placed in a tube furnace filled with ammonia for high-temperature reduction. The specific experimental parameters were: NH3 flow rate of 28 mL / min, heating rate of 5℃ / min, heating temperature of 800℃, and heating time of 2 h. The prepared sample was named MOF-NH3.
[0049] Example 1
[0050] Step 1: Add 10 mmol of titanate butyric acid and 20 mL of ethylene glycol to the hydrothermal reactor. Add 20 mL of water and 10 mmol of strontium nitrate to a beaker and sonicate to dissolve. Drop the solution from the beaker into the hydrothermal reactor; once a gel forms, pour the entire solution in and turn the stirrer to maximum. Then add 10 mL of sodium hydroxide solution (5 mol / L) to the hydrothermal reactor and stir at 1000 rpm for 30 min. After stirring, tighten the hydrothermal reactor and place it in an oven. Heat at 200℃ for 24 h. After heating, allow it to cool naturally to room temperature in a ventilated area. Remove the sample and wash it with deionized water until the pH reaches approximately 7. Place the washed sample in a forced-air drying oven and dry at 60℃ for 12 h.
[0051] Step 2: Mix the strontium titanate, SrCl2, and Al2O3 obtained in Step 1 at a molar ratio of 1:10:0.02 and grind them in a mortar. Place the mixed material in a crucible and heat it in a muffle furnace to 1100℃ at a heating rate of 5℃ per minute, hold for 5 hours, and then allow it to cool naturally to room temperature. Dissolve the extracted sample in 50 mL of deionized water using ultrasonication, wash five times by centrifugation, and then dry the cleaned sample in a drying oven at 60℃ for 12 hours. Name the Al-doped SrTiO3 treated with the molten salt STO.
[0052] Step 3: Prepare a solution with a volume ratio of H₂O:N,N-dimethylformamide:ethanol of 1:1:1. Dissolve 0.216g Ni(NO₃)₂·6H₂O, 0.216g Co(NO₃)₂·6H₂O, 0.15g trimesic acid, and 1.5g polyvinylpyrrolidone in 30mL of the above solution. Sonicate at room temperature for 30min, then transfer the solution to a 50mL polytetrafluoroethylene hydrothermal reactor. Place the reactor in an oven and heat at 150℃ for 10h, then allow it to cool naturally to room temperature. Wash the prepared sample, centrifuge and dry it, and name the sample NiCo-MOF.
[0053] Step 4: Disperse 100 mg STO and 1 mg NiCo-MOF in 5 mL of ethanol. Place the suspension in a glass test tube and evaporate to dryness using a constant-temperature oil bath at 80°C. Place the sample in a tube furnace filled with ammonia for high-temperature reduction. The specific experimental parameters are: NH3 flow rate 28 mL / min, heating rate 5°C / min, heating temperature 800°C, and heating time 2 h. Name the prepared sample 1%-MOF-STO-NH3.
[0054] Step 5: Add the 1% MOF-STO-NH3 prepared in Step 4 to pure water for photocatalytic water splitting to produce hydrogen. The specific steps are as follows:
[0055] 1) Add 10 mg of Al-doped strontium titanate photocatalyst loaded with NiCo alloy to a reactor with a volume of 105 mL, and add 80 mL of deionized water.
[0056] 2) Before illumination, purge the reactor with argon gas for 15 minutes to remove oxygen from the system;
[0057] 3) Turn on the magnetic stirrer and the xenon lamp.
[0058] Example 2
[0059] Step 1: Add 10 mmol of titanate butyric acid and 20 mL of ethylene glycol to the hydrothermal reactor. Add 20 mL of water and 10 mmol of strontium nitrate to a beaker and sonicate to dissolve. Drop the solution from the beaker into the hydrothermal reactor; once a gel forms, pour the entire solution in and turn the stirrer to maximum. Then add 10 mL of sodium hydroxide solution (5 mol / L) to the hydrothermal reactor and stir at 1000 rpm for 30 min. After stirring, tighten the hydrothermal reactor and place it in an oven. Heat at 200℃ for 24 h. After heating, allow it to cool naturally to room temperature in a ventilated area. Remove the sample and wash it with deionized water until the pH reaches approximately 7. Place the washed sample in a forced-air drying oven and dry at 60℃ for 12 h.
[0060] Step 2: Mix the strontium titanate, SrCl2, and Al2O3 obtained in Step 1 at a molar ratio of 1:10:0.02 and grind them in a mortar. Place the mixed material in a crucible and heat it in a muffle furnace to 1100℃ at a heating rate of 5℃ per minute, hold for 5 hours, and then allow it to cool naturally to room temperature. Dissolve the extracted sample in 50 mL of deionized water using ultrasonication, wash five times by centrifugation, and then dry the cleaned sample in a drying oven at 60℃ for 12 hours. Name the Al-doped SrTiO3 treated with the molten salt STO.
[0061] Step 3: Prepare a solution with a volume ratio of H₂O:N,N-dimethylformamide:ethanol of 1:1:1. Dissolve 0.216g Ni(NO₃)₂·6H₂O, 0.216g Co(NO₃)₂·6H₂O, 0.15g trimesic acid, and 1.5g polyvinylpyrrolidone in 30mL of the above solution. Sonicate at room temperature for 30min, then transfer the solution to a 50mL polytetrafluoroethylene hydrothermal reactor. Place the reactor in an oven and heat at 150℃ for 10h, then allow it to cool naturally to room temperature. Wash the prepared sample, centrifuge and dry it, and name the sample NiCo-MOF.
[0062] Step 4: Disperse 100 mg STO and 3 mg NiCo-MOF in 5 mL of ethanol. Place the suspension in a glass test tube and evaporate to dryness using a constant-temperature oil bath at 80°C. Place the sample in a tube furnace filled with ammonia for high-temperature reduction. The specific experimental parameters are: NH3 flow rate 28 mL / min, heating rate 5°C / min, heating temperature 800°C, and heating time 2 h. Name the prepared sample 3%-MOF-STO-NH3.
[0063] Step 5: Add the 3% MOF-STO-NH3 prepared in Step 4 to pure water for photocatalytic water splitting to produce hydrogen. The specific steps are as follows:
[0064] 1) Add 10 mg of Al-doped strontium titanate photocatalyst loaded with NiCo alloy to a reactor with a volume of 105 mL, and add 80 mL of deionized water.
[0065] 2) Before illumination, purge the reactor with argon gas for 15 minutes to remove oxygen from the system;
[0066] 3) Turn on the magnetic stirrer and the xenon lamp.
[0067] Example 3
[0068] Step 1: Add 10 mmol of titanate butyric acid and 20 mL of ethylene glycol to the hydrothermal reactor. Add 20 mL of water and 10 mmol of strontium nitrate to a beaker and sonicate to dissolve. Drop the solution from the beaker into the hydrothermal reactor; once a gel forms, pour the entire solution in and turn the stirrer to maximum. Then add 10 mL of sodium hydroxide solution (5 mol / L) to the hydrothermal reactor and stir at 1000 rpm for 30 min. After stirring, tighten the hydrothermal reactor and place it in an oven. Heat at 200℃ for 24 h. After heating, allow it to cool naturally to room temperature in a ventilated area. Remove the sample and wash it with deionized water until the pH reaches approximately 7. Place the washed sample in a forced-air drying oven and dry at 60℃ for 12 h.
[0069] Step 2: Mix the strontium titanate, SrCl2, and Al2O3 obtained in Step 1 at a molar ratio of 1:10:0.02 and grind them in a mortar. Place the mixed material in a crucible and heat it in a muffle furnace to 1100℃ at a heating rate of 5℃ per minute, hold for 5 hours, and then allow it to cool naturally to room temperature. Dissolve the extracted sample in 50 mL of deionized water using ultrasonication, wash five times by centrifugation, and then dry the cleaned sample in a drying oven at 60℃ for 12 hours. Name the Al-doped SrTiO3 treated with the molten salt STO.
[0070] Step 3: Prepare a solution with a volume ratio of H₂O:N,N-dimethylformamide:ethanol of 1:1:1. Dissolve 0.216g Ni(NO₃)₂·6H₂O, 0.216g Co(NO₃)₂·6H₂O, 0.15g trimesic acid, and 1.5g polyvinylpyrrolidone in 30mL of the above solution. Sonicate at room temperature for 30min, then transfer the solution to a 50mL polytetrafluoroethylene hydrothermal reactor. Place the reactor in an oven and heat at 150℃ for 10h, then allow it to cool naturally to room temperature. Wash the prepared sample, centrifuge and dry it, and name the sample NiCo-MOF.
[0071] Step 4: Disperse 100 mg STO and 5 mg NiCo-MOF in 5 mL of ethanol. Place the suspension in a glass test tube and evaporate to dryness using a constant-temperature oil bath at 80 °C. Place the sample in a tube furnace filled with ammonia for high-temperature reduction. The specific experimental parameters are: NH3 flow rate 28 mL / min, heating rate 5 °C / min, heating temperature 800 °C, and heating time 2 h. Name the prepared sample 5%-MOF-STO-NH3.
[0072] Step 5: Add the 5% MOF-STO-NH3 prepared in Step 4 to pure water for photocatalytic water splitting to produce hydrogen. The specific steps are as follows:
[0073] 1) Add 10 mg of Al-doped strontium titanate photocatalyst loaded with NiCo alloy to a reactor with a volume of 105 mL, and add 80 mL of deionized water.
[0074] 2) Before illumination, purge the reactor with argon gas for 15 minutes to remove oxygen from the system;
[0075] 3) Turn on the magnetic stirrer and the xenon lamp.
[0076] Example 4
[0077] Step 1: Add 10 mmol of titanate butyric acid and 20 mL of ethylene glycol to the hydrothermal reactor. Add 20 mL of water and 10 mmol of strontium nitrate to a beaker and sonicate to dissolve. Drop the solution from the beaker into the hydrothermal reactor; once a gel forms, pour the entire solution in and turn the stirrer to maximum. Then add 10 mL of sodium hydroxide solution (5 mol / L) to the hydrothermal reactor and stir at 1000 rpm for 30 min. After stirring, tighten the hydrothermal reactor and place it in an oven. Heat at 200℃ for 24 h. After heating, allow it to cool naturally to room temperature in a ventilated area. Remove the sample and wash it with deionized water until the pH reaches approximately 7. Place the washed sample in a forced-air drying oven and dry at 60℃ for 12 h.
[0078] Step 2: Mix the strontium titanate, SrCl2, and Al2O3 obtained in Step 1 at a molar ratio of 1:10:0.02 and grind them in a mortar. Place the mixed material in a crucible and heat it in a muffle furnace to 1100℃ at a heating rate of 5℃ per minute, hold for 5 hours, and then allow it to cool naturally to room temperature. Dissolve the extracted sample in 50 mL of deionized water using ultrasonication, wash five times by centrifugation, and then dry the cleaned sample in a drying oven at 60℃ for 12 hours. Name the Al-doped SrTiO3 treated with the molten salt STO.
[0079] Step 3: Prepare a solution with a volume ratio of H₂O:N,N-dimethylformamide:ethanol of 1:1:1. Dissolve 0.216g Ni(NO₃)₂·6H₂O, 0.216g Co(NO₃)₂·6H₂O, 0.15g trimesic acid, and 1.5g polyvinylpyrrolidone in 30mL of the above solution. Sonicate at room temperature for 30min, then transfer the solution to a 50mL polytetrafluoroethylene hydrothermal reactor. Place the reactor in an oven and heat at 150℃ for 10h, then allow it to cool naturally to room temperature. Wash the prepared sample, centrifuge and dry it, and name the sample NiCo-MOF.
[0080] Step 4: Disperse 100 mg STO and 7 mg NiCo-MOF in 5 mL of ethanol. Place the suspension in a glass test tube and evaporate to dryness using a constant-temperature oil bath at 80°C. Place the sample in a tube furnace filled with ammonia for high-temperature reduction. The specific experimental parameters are: NH3 flow rate 28 mL / min, heating rate 5°C / min, heating temperature 800°C, and heating time 2 h. Name the prepared sample 7%-MOF-STO-NH3.
[0081] Step 5: Add the 7% MOF-STO-NH3 prepared in Step 4 to pure water for photocatalytic water splitting to produce hydrogen. The specific steps are as follows:
[0082] 1) Add 10 mg of Al-doped strontium titanate photocatalyst loaded with NiCo alloy to a reactor with a volume of 105 mL, and add 80 mL of deionized water.
[0083] 2) Before illumination, purge the reactor with argon gas for 15 minutes to remove oxygen from the system;
[0084] 3) Turn on the magnetic stirrer and the xenon lamp.
[0085] Example 5
[0086] Step 1: Same as Example 1;
[0087] Step 2: Same as Example 1;
[0088] Step 3: Same as Example 1;
[0089] Step 4: Grind 100 mg STO and 4 mg NiCo-MOF evenly to obtain a mixture. Then, place the mixture in a tube furnace filled with ammonia for high-temperature reduction to obtain the Ni,Co bimetallic alloy-strontium titanate composite photocatalyst. The specific experimental parameters for high-temperature reduction are: NH3 flow rate of 60 mL / min, heating rate of 10℃ / min, heating temperature of 700℃, and heating time of 1.5 h.
[0090] Example 6
[0091] Step 1: Same as Example 1;
[0092] Step 2: Same as Example 1;
[0093] Step 3: Same as Example 1;
[0094] Step 4: Disperse 100 mg STO and 6 mg NiCo-MOF in 10 mL of water. Place the suspension in a glass test tube and evaporate to dryness using a constant-temperature oil bath at 100 °C. Place the sample in a tube furnace filled with ammonia for high-temperature reduction to obtain the Ni,Co bimetallic alloy-strontium titanate composite photocatalyst. The specific parameters for the high-temperature reduction experiment were: NH3 flow rate 20 mL / min, heating rate 7 °C / min, heating temperature 600 °C, and heating time 2 h.
[0095] Example 7
[0096] Step 1: Same as Example 1;
[0097] Step 2: Same as Example 1;
[0098] Step 3: Same as Example 1;
[0099] Step 4: Disperse 100 mg STO and 10 mg NiCo-MOF in 7 mL of methanol. Place the suspension in a glass test tube and evaporate to dryness using a constant-temperature oil bath at 65 °C. Place the sample in a tube furnace filled with ammonia for high-temperature reduction to obtain the Ni,Co bimetallic alloy-strontium titanate composite photocatalyst. The specific parameters for the high-temperature reduction experiment were: NH3 flow rate 100 mL / min, heating rate 9 °C / min, heating temperature 1000 °C, and heating time 1 h.
[0100] Figure 1 These are X-ray diffraction (XRD) patterns of a NiCo bimetallic alloy (MOF-NH3), Al-doped strontium titanate (STO), and an Al-doped strontium titanate supported on a NiCo bimetallic alloy (3%-MOF-STO-NH3). The characteristic peaks of the XRD pattern of NiCo-MOF after high-temperature ammonia treatment match the characteristic peaks of Ni and Co metals, indicating that NiCo alloys can be prepared by high-temperature ammonia calcination of NiCo-MOF. The structure of strontium titanate did not change significantly before and after high-temperature ammonia treatment.
[0101] Figure 2 Images a) and b) are scanning electron microscope (SEM) and transmission electron microscope (TEM) images of 3% MOF-STO-NH3. These further demonstrate the NiCo alloy loaded on the strontium titanate surface.
[0102] Figure 3 The graph shows the photocatalytic hydrogen production rates of Al-doped strontium titanate supported on NiCo bimetallic alloys with different proportions. It can be seen that the catalyst exhibits the highest catalytic activity when the NiCo-MOF addition is 3%, with a photocatalytic water splitting hydrogen production rate of 979.9 μmol / h. -1 g -1 The quantum efficiency at 350 nm is 11.9%.
[0103] The formula for calculating the apparent quantum efficiency (AQY%) of the photocatalytic hydrogen production reaction is as follows:
[0104]
[0105] Figure 4 The graph shows the stability of the 3% MOF-STO-NH3 photocatalytic hydrogen production, indicating that the catalyst has good stability.
[0106] The above description is only of the preferred embodiment of the present invention and should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All variations made within the scope of the independent claims of the present invention are also within the scope of protection of the present invention.
[0107] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
Claims
1. The application of a Ni,Co bimetallic alloy-strontium titanate composite photocatalyst in photocatalytic hydrogen production, wherein the preparation method of the Ni,Co bimetallic alloy-strontium titanate composite photocatalyst includes the following steps: Al-doped strontium titanate and a metal-organic framework containing Ni and Co bimetals were mixed evenly and then reduced under an ammonia atmosphere to obtain a Ni,Co bimetallic alloy-strontium titanate composite photocatalyst.
2. The application of the Ni,Co bimetallic alloy-strontium titanate composite photocatalyst according to claim 1 in photocatalytic hydrogen production, characterized in that, Al-doped strontium titanate was prepared by a hydrothermal method and molten salt.
3. The application of the Ni,Co bimetallic alloy-strontium titanate composite photocatalyst according to claim 1 in photocatalytic hydrogen production, characterized in that, In metal-organic frameworks containing Ni and Co bimetals, the molar ratio of Ni to Co is 1:0.1-1.
4. The application of the Ni,Co bimetallic alloy-strontium titanate composite photocatalyst according to claim 1 in photocatalytic hydrogen production, characterized in that, The mass ratio of Al-doped strontium titanate to a metal-organic framework containing Ni,Co bimetals is 100 mg: 1-10 mg.
5. The application of the Ni,Co bimetallic alloy-strontium titanate composite photocatalyst according to claim 1 in photocatalytic hydrogen production, characterized in that, The mixing is carried out by grinding or by dispersing Al-doped strontium titanate and a metal-organic framework containing Ni and Co bimetals in a solvent and then evaporating to dryness.
6. The application of the Ni,Co bimetallic alloy-strontium titanate composite photocatalyst according to claim 1 in photocatalytic hydrogen production, characterized in that, The ammonia flow rate is 20-100 mL / min.
7. The application of the Ni,Co bimetallic alloy-strontium titanate composite photocatalyst according to claim 1 in photocatalytic hydrogen production, characterized in that, The reduction reaction is carried out at a temperature of 600-1000 ℃ for 1-5 h.
8. The application of the Ni,Co bimetallic alloy-strontium titanate composite photocatalyst according to claim 7 in photocatalytic hydrogen production, characterized in that, Heating to 600-1000 ℃ at a heating rate of 5-10 ℃ / min.