SrTiO3 photocatalytic material derived from high-exposure crystal form based on TiO2 as well as preparation method and application of SrTiO3 photocatalytic material

Abstract

The invention relates to the technical field of preparation of photocatalytic materials, and particularly discloses a high-exposure crystal form derived SrTiO3 photocatalytic material based on TiO2 and a preparation method and application thereof.The high-exposure {001} crystal form TiO2 serves as a precursor, the high-exposure {001} crystal form TiO2 has rich surface active sites, and in the process of deriving SrTiO3, the surface active sites of the high-exposure {001} crystal form TiO2 are rich, so that the surface active sites of the high-exposure {001} crystal form TiO2 are reduced, and the photocatalytic performance of the high-exposure {001} crystal form SrTiO3 photocatalytic material is improved. The active sites are reserved and are further optimized through element reaction and structure reconstruction, and due to the special crystal structure of the highly-exposed {001} crystal form TiO2, photo-induced electrons and holes are easy to separate and directionally transmit; in addition, the SrTiO3 derived from the highly exposed {001} crystal form TiO2 can expose more active sites, so that the photocatalytic activity is improved.

Description

Technical Field

[0001] This invention relates to the field of photocatalytic material preparation technology, specifically to a SrTiO3 photocatalytic material derived from the high-exposure crystal form of TiO2, its preparation method, and its application. Background Technology

[0002] Against the backdrop of the accelerated global energy structure transition towards green and low-carbon development, photocatalytic water splitting technology, with its unique advantage of utilizing solar energy to decompose water into H2 and O2, has become a key breakthrough for achieving large-scale production of clean energy hydrogen. H2, as an ideal energy carrier with zero carbon emissions, is expected to fundamentally change the highly polluting status quo of traditional fossil fuel-based hydrogen production through the green photocatalytic water splitting method, opening up a new path to solve the dual challenges of the energy crisis and environmental pollution.

[0003] Photocatalytic water splitting uses semiconductor photocatalytic materials as its core. In principle, when light with energy greater than the semiconductor bandgap shines on the catalyst surface, electrons in the catalyst's valence band absorb the light energy and jump to the conduction band, generating photogenerated electron-hole pairs. The electrons migrate to the catalyst surface, reducing hydrogen ions in the water to H2, while the holes oxidize the water to O2. The entire process achieves the splitting of water into H2 and O2 driven by light energy through the separation and migration of photogenerated charge carriers, thereby converting solar energy into chemical energy stored in H2.

[0004] SrTiO3 is a traditional perovskite-type semiconductor photocatalyst with a band gap of 3.2 eV. It primarily responds to ultraviolet light and exhibits excellent dielectric constant, chemical stability, and thermal stability. However, this catalyst has an extremely high photogenerated electron-hole recombination rate and a scarcity of surface active sites, making it less than ideal for photocatalytic water splitting. Furthermore, it consumes a lot of energy in commonly used high-temperature solid-state synthesis methods.

[0005] TiO2 is a common metal oxide with stable chemical properties, good optical performance and excellent catalytic activity. Its band gap width is close to that of SrTiO3. The synthesis methods of TiO2 with different high-exposure crystal forms are also relatively mature, and its crystal facets are highly controllable, which is expected to optimize the light absorption and charge transport performance of SrTiO3. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a SrTiO3 photocatalytic material derived from the high-exposed crystal form of TiO2, its preparation method, and its application. The present invention utilizes the structural advantages of the high-exposed crystal form of TiO2 and obtains an SrTiO3 photocatalytic material with high active sites and efficient charge separation capability through a specific preparation process, thereby improving its catalytic performance in the photocatalytic total water splitting reaction.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a SrTiO3 photocatalytic material derived from the high-exposed crystal form of TiO2, wherein the SrTiO3 photocatalytic material is derived by using the high-exposed {001} crystal form of TiO2 as a titanium source and a soluble strontium salt as a strontium source.

[0008] In the technical solution disclosed in this invention, the preparation method of the high-exposed {001} crystal form of TiO2 is as follows: Tetrabutyl titanate and hydrofluoric acid are mixed evenly, and then a hydrothermal reaction is carried out. After the reaction is completed, the mixture is centrifuged, washed, and dried to obtain a white powder of TiO2 with a high-exposed {001} crystal form.

[0009] The volume ratio of tetrabutyl titanate to hydrofluoric acid is 5.5-8.5:1, for example, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0010] Specifically, the hydrofluoric acid has a mass fraction of 45-50%.

[0011] Specifically, the hydrothermal reaction temperature is 150-180℃, for example, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃, and 180℃ can be selected; the hydrothermal reaction time is 24-48h, for example, 24h, 30h, 36h, 42h, and 48h can be selected, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0012] Secondly, the present invention provides a method for preparing the above-mentioned SrTiO3 photocatalytic material, comprising the following steps: dissolving TiO2 white powder with high exposure {001} crystal form and soluble strontium salt in deionized water, then adding alkaline solution, stirring evenly, and then carrying out a hydrothermal reaction. After the reaction is completed, cooling to room temperature, and then centrifuging, washing, drying and calcining to obtain the SrTiO3 photocatalytic material.

[0013] In the technical solution disclosed in this invention, the molar ratio of the highly exposed {001} crystal form TiO2 white powder to the soluble strontium salt is 1:1-1.15, for example, 1:1, 1:1.05, 1:1.1, 1:15 can be selected, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] Specifically, the soluble strontium salt is selected from strontium hydroxide octahydrate, strontium chloride hexahydrate, or strontium acetate.

[0015] Specifically, the alkaline solution is selected from sodium hydroxide solution or potassium hydroxide solution, and the concentration of the alkaline solution is 6-10 mol / L. For example, 6 mol / L, 6.5 mol / L, 7 mol / L, 7.5 mol / L, 8 mol / L, 8.5 mol / L, 9 mol / L, 9.5 mol / L, and 10 mol / L can be selected, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] In the technical solution disclosed in this invention, the temperature of the hydrothermal reaction is 140-180℃, for example, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃, 180℃ can be selected; the time of the hydrothermal reaction is 12-18h, for example, 12h, 13h, 14h, 15h, 16h, 17h, 18h can be selected, but it is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0017] In the technical solution disclosed in this invention, the calcination temperature is 500-1100℃, for example, 500℃, 600℃, 700℃, 800℃, 900℃, 1000℃, or 1100℃ can be selected; the calcination time is 2-4h, for example, 2h, 2.5h, 3h, 3.5h, or 4h can be selected, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0018] Thirdly, the present invention provides the application of the above-mentioned SrTiO3 photocatalytic material in photocatalytic water splitting.

[0019] In the technical solution disclosed in this invention, the specific steps of the application are as follows: the synthesized SrTiO3 photocatalytic material is pretreated by photodepositing a certain mass percentage of co-catalyst in sequence, then ultrasonically dispersed in deionized water, and then transferred to a Pyrex reaction cell, connected to a hydrogen production system, the vacuum pump is turned on to evacuate the system to remove air, argon gas is introduced, and a condensate device is connected, and the catalytic reaction is carried out under light irradiation.

[0020] Specifically, based on the mass of the SrTiO3 photocatalytic material, the co-catalyst comprises 0.1 wt% Rh, 0.05 wt% Cr, and 0.05 wt% Co.

[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) The SrTiO3 photocatalytic material provided by the present invention uses TiO2 with high exposure {001} crystal form as a precursor, which has abundant surface active sites. In the process of derivatization into SrTiO3, these active sites are not only retained, but also further optimized through elemental reactions and structural reconstruction. Furthermore, due to the special crystal structure of TiO2 with high exposure {001} crystal form, photogenerated electrons and holes are easily separated and directionally transported. In addition, SrTiO3 derived from TiO2 with high exposure {001} crystal form can expose more active sites and improve photocatalytic activity.

[0022] (2) The preparation method used in this invention is mainly based on hydrothermal synthesis and calcination processes. These two processes have the advantages of simple operation, low equipment requirements, and easy large-scale production in the field of material preparation. By precisely controlling process parameters such as raw material ratio, reaction temperature, and time, this invention can stably prepare SrTiO3 photocatalytic materials with excellent performance, providing a reliable technical guarantee for industrial production, which is conducive to reducing production costs and improving production efficiency. Attached Figure Description

[0023] Figure 1 This is an ultra-high resolution scanning electron microscope image of the TiO2 white powder with high exposure {001} crystal form prepared in Example 1 of the present invention; Figure 2 This is an ultra-high resolution scanning electron microscope image of the SrTiO3 photocatalytic material prepared in Example 2 of this invention; Figure 3 This is the X-ray powder diffraction pattern of the TiO2 precursor with high exposure {001} crystal form prepared in Example 1 of the present invention; Figure 4 This is the X-ray powder diffraction pattern of the SrTiO3 photocatalytic material prepared in Example 2 of this invention; Figure 5 This is a comparison chart of the overall water splitting performance of the SrTiO3 photocatalytic materials prepared in Examples 1-3 and Comparative Examples 1-3 of this invention. Detailed Implementation

[0024] The present invention will be further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0025] It should be noted that, unless otherwise specified, all chemical reagents involved in this invention were purchased through commercial channels.

[0026] Example 1 A method for preparing TiO2-derived SrTiO3 photocatalytic material utilizing a highly exposed {001} crystal form includes the following steps: S1. Measure 30 mL of tetrabutyl titanate solution into a 100 mL polytetrafluoroethylene liner using a 50 mL graduated cylinder. Then, add 3.6 mL of 49 wt% hydrofluoric acid dropwise to the solution using a pipette. Place the liner on a magnetic stirrer and stir at room temperature for 30 min. Then, place the liner into a high-pressure reactor and tighten it to ensure safety. Finally, place it in a homogeneous reactor and heat it to 180 °C at a rate of 5 °C / min. Hold the temperature for 24 h. During the reaction, by controlling the temperature and time, TiO2 crystals are preferentially grown along the {001} crystal plane to form highly exposed {001} crystal form TiO2. After the hydrothermal reaction is completed, after the reactor cools to room temperature, remove the liner. Wash the reaction solution by centrifuging three times with anhydrous ethanol and water, respectively. Then, dry the washed product in a vacuum oven at 60 °C for 12 h, with the centrifuge speed at 5000 r / min and the centrifugation time at 3 min. Finally, the dried sample was placed in a mortar and ground to obtain a white powder, which is TiO2 with high exposure {001} crystal form.

[0027] S2. Using the high-exposure {001} crystal form TiO2 white powder prepared in S1 as a precursor, first take 30 mL of deionized water in a polytetrafluoroethylene liner, dissolve the precursor and strontium hydroxide octahydrate in the deionized water at a molar ratio of 1:1 (weigh 0.05 g of high-exposure {001} crystal form TiO2 and 0.166 g of strontium hydroxide octahydrate), then add 1.5 mL of 10 mol / L sodium hydroxide solution, place the liner on a magnetic stirrer and stir at room temperature for 30 min, then place the liner in a high-pressure reactor and tighten it to ensure its safety, finally place it in a homogeneous reactor, heat it to 150 °C at a heating rate of 5 °C / min, and keep it at that temperature for 12 h. After the hydrothermal reaction was completed, the liner was removed from the reactor after it cooled to room temperature. The reaction solution was washed three times each with anhydrous ethanol and water. The washed product was then dried in a vacuum oven at 60°C for 12 hours, with a centrifuge speed of 8000 r / min and a centrifugation time of 5 minutes. The dried sample was then ground in a mortar to obtain a white powder. The white powder was then placed in a crucible and placed in a muffle furnace, heated to 500°C at a heating rate of 5°C / min, and calcined for 3 hours to obtain the SrTiO3 photocatalyst material.

[0028] Example 2 A method for preparing TiO2-derived SrTiO3 photocatalytic material utilizing a highly exposed {001} crystal form includes the following steps: S1. Measure 30 mL of tetrabutyl titanate solution into a 100 mL polytetrafluoroethylene liner using a 50 mL graduated cylinder. Then, add 3.6 mL of 49 wt% hydrofluoric acid dropwise to the solution using a pipette. Place the liner on a magnetic stirrer and stir at room temperature for 30 min. Then, place the liner into a high-pressure reactor and tighten it to ensure safety. Finally, place it in a homogeneous reactor and heat it to 180 °C at a rate of 5 °C / min. Hold the temperature for 24 h. During the reaction, by controlling the temperature and time, TiO2 crystals are preferentially grown along the {001} crystal plane to form highly exposed {001} crystal form TiO2. After the hydrothermal reaction is completed, after the reactor cools to room temperature, remove the liner. Wash the reaction solution by centrifuging three times with anhydrous ethanol and water, respectively. Then, dry the washed product in a vacuum oven at 60 °C for 12 h, with the centrifuge speed at 5000 r / min and the centrifugation time at 3 min. Finally, the dried sample was placed in a mortar and ground to obtain a white powder, which is TiO2 with high exposure {001} crystal form.

[0029] S2. Using the highly exposed {001} crystal form TiO2 white powder prepared in S1 as a precursor, first take 30 mL of deionized water in a polytetrafluoroethylene liner, and dissolve the precursor and strontium hydroxide octahydrate in the deionized water at a molar ratio of 1:1 (weigh 0.05 g of highly exposed {001} crystal form TiO2 and 0.166 g of strontium hydroxide octahydrate). Then add 1.5 mL of 10 mol / L sodium hydroxide solution. Place the liner on a magnetic stirrer and stir at room temperature for 30 min. Then place the liner into a high-pressure reactor and tighten it to ensure safety. Finally, place it in a homogeneous reactor and heat it to 150 °C at a rate of 5 °C / min, and hold it at that temperature for 12 h. After the hydrothermal reaction was completed, the liner was removed from the reactor after it cooled to room temperature. The reaction solution was washed three times each with anhydrous ethanol and water. The washed product was then dried in a vacuum oven at 60°C for 12 hours, with a centrifuge speed of 8000 r / min and a centrifugation time of 5 minutes. The dried sample was then ground in a mortar to obtain a white powder. Finally, the white powder was placed in a crucible and placed in a muffle furnace, heated to 950°C at a heating rate of 5°C / min, and calcined for 3 hours to obtain the SrTiO3 photocatalyst material.

[0030] Example 3 A method for preparing TiO2-derived SrTiO3 photocatalytic material utilizing a highly exposed {001} crystal form includes the following steps: S1. Measure 30 mL of tetrabutyl titanate solution into a 100 mL polytetrafluoroethylene liner using a 50 mL graduated cylinder. Then, add 3.6 mL of 49 wt% hydrofluoric acid dropwise to the solution using a pipette. Place the liner on a magnetic stirrer and stir at room temperature for 30 min. Then, place the liner into a high-pressure reactor and tighten it to ensure safety. Finally, place it in a homogeneous reactor and heat it to 180 °C at a rate of 5 °C / min. Hold the temperature for 24 h. During the reaction, by controlling the temperature and time, TiO2 crystals are preferentially grown along the {001} crystal plane to form highly exposed {001} crystal form TiO2. After the hydrothermal reaction is completed, after the reactor cools to room temperature, remove the liner. Wash the reaction solution by centrifuging three times with anhydrous ethanol and water, respectively. Then, dry the washed product in a vacuum oven at 60 °C for 12 h, with the centrifuge speed at 5000 r / min and the centrifugation time at 3 min. Finally, the dried sample was placed in a mortar and ground to obtain a white powder, which is TiO2 with high exposure {001} crystal form.

[0031] S2. Using the highly exposed {001} crystal form TiO2 white powder prepared in S1 as a precursor, first take 30 mL of deionized water in a polytetrafluoroethylene liner, and dissolve the precursor and strontium hydroxide octahydrate in the deionized water at a molar ratio of 1:1 (weigh 0.05 g of highly exposed {001} crystal form TiO2 and 0.166 g of strontium hydroxide octahydrate). Then add 1.5 mL of 10 mol / L sodium hydroxide solution. Place the liner on a magnetic stirrer and stir at room temperature for 30 min. Then place the liner into a high-pressure reactor and tighten it to ensure safety. Finally, place it in a homogeneous reactor and heat it to 150 °C at a rate of 5 °C / min, and hold it at that temperature for 12 h. After the hydrothermal reaction was completed, the liner was removed from the reactor after it cooled to room temperature. The reaction solution was washed three times each with anhydrous ethanol and water. The washed product was then dried in a vacuum oven at 60°C for 12 hours, with a centrifuge speed of 8000 r / min and a centrifugation time of 5 minutes. The dried sample was then ground in a mortar to obtain a white powder. Finally, the white powder was placed in a crucible and placed in a muffle furnace, heated to 500°C at a heating rate of 5°C / min, and calcined for 3 hours. The resulting powder was then subjected to a second calcination, placed in a muffle furnace, heated to 950°C at a heating rate of 5°C / min, and calcined for 3 hours to obtain the SrTiO3 photocatalytic material.

[0032] Example 4 A method for preparing TiO2-derived SrTiO3 photocatalytic material utilizing a highly exposed {001} crystal form includes the following steps: S1. Measure 30 mL of tetrabutyl titanate solution into a 100 mL polytetrafluoroethylene liner using a 50 mL graduated cylinder. Then, add 3.6 mL of 49 wt% hydrofluoric acid dropwise to the solution using a pipette. Place the liner on a magnetic stirrer and stir at room temperature for 30 min. Then, place the liner into a high-pressure reactor and tighten it to ensure safety. Finally, place it in a homogeneous reactor and heat it to 180 °C at a rate of 5 °C / min. Hold the temperature for 24 h. During the reaction, by controlling the temperature and time, TiO2 crystals are preferentially grown along the {001} crystal plane to form highly exposed {001} crystal form TiO2. After the hydrothermal reaction is completed, after the reactor cools to room temperature, remove the liner. Wash the reaction solution by centrifuging three times with anhydrous ethanol and water, respectively. Then, dry the washed product in a vacuum oven at 60 °C for 12 h, with the centrifuge speed at 5000 r / min and the centrifugation time at 3 min. Finally, the dried sample was placed in a mortar and ground to obtain a white powder, which is TiO2 with high exposure {001} crystal form.

[0033] S2. Using the highly exposed {001} crystal form TiO2 white powder prepared in S1 as a precursor, first take 30 mL of deionized water in a polytetrafluoroethylene liner, and dissolve the precursor and strontium hydroxide octahydrate in the deionized water at a molar ratio of 1:1.05 (weigh 0.05 g of highly exposed {001} crystal form TiO2 and 0.175 g of strontium hydroxide octahydrate). Then add 1.5 mL of 10 mol / L sodium hydroxide solution. Place the liner on a magnetic stirrer and stir at room temperature for 30 min. Then place the liner into a high-pressure reactor and tighten it to ensure safety. Finally, place it in a homogeneous reactor and heat it to 150 °C at a rate of 5 °C / min, and hold it at that temperature for 12 h. After the hydrothermal reaction was completed, the liner was removed from the reactor after it cooled to room temperature. The reaction solution was washed three times each with anhydrous ethanol and water. The washed product was then dried in a vacuum oven at 60°C for 12 hours, with a centrifuge speed of 8000 r / min and a centrifugation time of 5 minutes. The dried sample was then ground in a mortar to obtain a white powder. The white powder was then placed in a crucible and placed in a muffle furnace, heated to 950°C at a heating rate of 5°C / min, and calcined for 3 hours to obtain the SrTiO3 photocatalyst material.

[0034] Example 5 A method for preparing TiO2-derived SrTiO3 photocatalytic material utilizing a highly exposed {001} crystal form includes the following steps: S1. Measure 30 mL of tetrabutyl titanate solution into a 100 mL polytetrafluoroethylene liner using a 50 mL graduated cylinder. Then, add 3.6 mL of 49 wt% hydrofluoric acid dropwise to the solution using a pipette. Place the liner on a magnetic stirrer and stir at room temperature for 30 min. Then, place the liner into a high-pressure reactor and tighten it to ensure safety. Finally, place it in a homogeneous reactor and heat it to 180 °C at a rate of 5 °C / min. Hold the temperature for 24 h. During the reaction, by controlling the temperature and time, TiO2 crystals are preferentially grown along the {001} crystal plane to form highly exposed {001} crystal form TiO2. After the hydrothermal reaction is completed, after the reactor cools to room temperature, remove the liner. Wash the reaction solution by centrifuging three times with anhydrous ethanol and water, respectively. Then, dry the washed product in a vacuum oven at 60 °C for 12 h, with the centrifuge speed at 5000 r / min and the centrifugation time at 3 min. Finally, the dried sample was placed in a mortar and ground to obtain a white powder, which is TiO2 with high exposure {001} crystal form.

[0035] S2. Using the highly exposed {001} crystal form TiO2 white powder prepared in S1 as a precursor, first take 30 mL of deionized water in a polytetrafluoroethylene liner, and dissolve the precursor and strontium hydroxide octahydrate in the deionized water at a molar ratio of 1:1.1 (weigh 0.05 g of highly exposed {001} crystal form TiO2 and 0.183 g of strontium hydroxide octahydrate). Then add 1.5 mL of 10 mol / L sodium hydroxide solution. Place the liner on a magnetic stirrer and stir at room temperature for 30 min. Then place the liner into a high-pressure reactor and tighten it to ensure safety. Finally, place it in a homogeneous reactor and heat it to 150 °C at a rate of 5 °C / min, and hold it at that temperature for 12 h. After the hydrothermal reaction was completed, the liner was removed from the reactor after it cooled to room temperature. The reaction solution was washed three times each with anhydrous ethanol and water. The washed product was then dried in a vacuum oven at 60°C for 12 hours, with a centrifuge speed of 8000 r / min and a centrifugation time of 5 minutes. The dried sample was then ground in a mortar to obtain a white powder. Finally, the white powder was placed in a crucible and placed in a muffle furnace, heated to 950°C at a heating rate of 5°C / min, and calcined for 3 hours to obtain the SrTiO3 photocatalyst material.

[0036] Example 6 A method for preparing TiO2-derived SrTiO3 photocatalytic material utilizing a highly exposed {001} crystal form includes the following steps: S1. Measure 30 mL of tetrabutyl titanate solution into a 100 mL polytetrafluoroethylene liner using a 50 mL graduated cylinder. Then, add 3.6 mL of 49 wt% hydrofluoric acid dropwise to the solution using a pipette. Place the liner on a magnetic stirrer and stir at room temperature for 30 min. Then, place the liner into a high-pressure reactor and tighten it to ensure safety. Finally, place it in a homogeneous reactor and heat it to 180 °C at a rate of 5 °C / min. Hold the temperature for 24 h. During the reaction, by controlling the temperature and time, TiO2 crystals are preferentially grown along the {001} crystal plane to form highly exposed {001} crystal form TiO2. After the hydrothermal reaction is completed, after the reactor cools to room temperature, remove the liner. Wash the reaction solution by centrifuging three times with anhydrous ethanol and water, respectively. Then, dry the washed product in a vacuum oven at 60 °C for 12 h, with the centrifuge speed at 5000 r / min and the centrifugation time at 3 min. Finally, the dried sample was placed in a mortar and ground to obtain a white powder, which is TiO2 with high exposure {001} crystal form.

[0037] S2. Using the highly exposed {001} crystal form TiO2 white powder prepared in S1 as a precursor, first take 30 mL of deionized water in a polytetrafluoroethylene liner, and dissolve the precursor and strontium hydroxide octahydrate in the deionized water at a molar ratio of 1:1.15 (weigh 0.05 g of highly exposed {001} crystal form TiO2 and 0.191 g of strontium hydroxide octahydrate). Then add 1.5 mL of 10 mol / L sodium hydroxide solution. Place the liner on a magnetic stirrer and stir at room temperature for 30 min. Then place the liner into a high-pressure reactor and tighten it to ensure safety. Finally, place it in a homogeneous reactor and heat it to 150 °C at a rate of 5 °C / min, and hold it at that temperature for 12 h. After the hydrothermal reaction was completed, the liner was removed from the reactor after it cooled to room temperature. The reaction solution was washed three times each with anhydrous ethanol and water. The washed product was then dried in a vacuum oven at 60°C for 12 hours, with a centrifuge speed of 8000 r / min and a centrifugation time of 5 minutes. The dried sample was then ground in a mortar to obtain a white powder. Finally, the white powder was placed in a crucible and placed in a muffle furnace, heated to 950°C at a heating rate of 5°C / min, and calcined for 3 hours to obtain the SrTiO3 photocatalyst material.

[0038] Comparative Example 1 The preparation of SrTiO3 photocatalytic materials using P25 TiO2 as the Ti source includes the following steps: First, 30 mL of deionized water was placed in a polytetrafluoroethylene (PTFE) liner. The TiO2 precursor and strontium hydroxide octahydrate were dissolved in the deionized water at a molar ratio of 1:1 (0.05 g of TiO2 precursor and 0.166 g of strontium hydroxide octahydrate were weighed). Then, 1.5 mL of a 10 mol / L sodium hydroxide solution was added. The liner was placed on a magnetic stirrer and stirred at room temperature for 30 min. The liner was then placed in a high-pressure reactor and tightened to ensure safety. Finally, the reactor was placed in a homogeneous reactor and heated to 150 °C at a rate of 5 °C / min, and held at this temperature for 12 h. After the hydrothermal reaction was completed, the liner was removed after the reactor cooled to room temperature. The reaction solution was washed three times each with anhydrous ethanol and water by centrifugation. The washed product was then dried in a vacuum oven at 60 °C for 12 h, with the centrifuge speed at 8000 r / min and the centrifugation time at 5 min. The dried sample was then ground in a mortar to obtain a white powder. Finally, the white powder was placed in a crucible and placed in a muffle furnace, heated to 950°C at a heating rate of 5°C / min, and calcined for 3 hours to obtain the SrTiO3 photocatalytic material.

[0039] Compared with Comparative Example 1 and Example 2, SrTiO3 photocatalytic materials were prepared by using P25 TiO2 as the Ti source.

[0040] Comparative Example 2 A method for preparing SrTiO3 photocatalytic material includes the following steps: 1.48g of strontium carbonate and 1.2g of titanium dioxide (CAS No.: 13463-67-7) were mixed in stoichiometric ratio and ground thoroughly in an agate mortar for 30 minutes to ensure uniform mixing. The mixed powder was then transferred to a crucible, placed in a muffle furnace, heated to 950℃ at a heating rate of 5℃ / min, and calcined at this temperature for 3 hours. After cooling, the conventional SrTiO3 photocatalytic material was obtained.

[0041] Compared with Comparative Example 2, SrTiO3 photocatalytic materials were prepared by conventional solid-phase synthesis method.

[0042] Comparative Example 3 A method for preparing TiO2-derived SrTiO3 photocatalytic material utilizing a highly exposed {101} crystal form includes the following steps: S1. Measure 70 mL of a 10 mol / L sodium hydroxide solution into a 100 mL polytetrafluoroethylene (PTFE) liner using a graduated cylinder. Then weigh 0.6 g of P25 TiO2 and add it to the solution. Place the liner on a magnetic stirrer and stir at room temperature for 30 min. Then place the liner into a high-pressure reactor and tighten it to ensure safety. Finally, place it in a homogeneous reactor and heat it to 200 °C at a rate of 5 °C / min, holding it at that temperature for 48 h. After the hydrothermal reaction is complete, let the reactor cool to room temperature and remove the liner. Wash the reaction solution with deionized water until the pH reaches 7. Then, place the washed product in a vacuum oven at 60 °C and dry it for 12 h, using a centrifuge at 3000 r / min for 3 min. Finally, grind the dried sample in a mortar to obtain the TiO2 nanowire precursor.

[0043] S2. Measure 30 mL of deionized water into a 100 mL polytetrafluoroethylene (PTFE) liner using a graduated cylinder. Then weigh 0.1 g of the TiO2 nanowire precursor prepared in S1 and add it to the above solution. Place the liner on a magnetic stirrer and stir at room temperature for 30 min. Then place the liner into a high-pressure reactor and tighten it to ensure safety. Finally, place it in a homogeneous reactor and heat it to 200 °C at a rate of 5 °C / min, and hold it at that temperature for 3 h. After the hydrothermal reaction is complete, wait for the reactor to cool to room temperature, then remove the liner. Wash the reaction solution with deionized water by centrifugation at 8000 r / min for 3 min. Then place the washed product in a vacuum oven at 60 °C and dry it for 12 h. Finally, grind the dried sample in a mortar to obtain TiO2 with high exposure of the {101} crystal form.

[0044] S3. Using the highly exposed {101} crystal form TiO2 white powder prepared in S2 as a precursor, first take 30 mL of deionized water in a polytetrafluoroethylene liner, and dissolve the precursor and strontium hydroxide octahydrate in the deionized water at a molar ratio of 1:1 (weigh 0.05 g of highly exposed {101} crystal form TiO2 and 0.166 g of strontium hydroxide octahydrate). Then add 1.5 mL of 10 mol / L sodium hydroxide solution. Place the liner on a magnetic stirrer and stir at room temperature for 30 min. Then place the liner into a high-pressure reactor and tighten it to ensure safety. Finally, place it in a homogeneous reactor and heat it to 150 °C at a rate of 5 °C / min, and hold it at that temperature for 12 h. After the hydrothermal reaction was completed, the liner was removed from the reactor after it cooled to room temperature. The reaction solution was washed three times each with anhydrous ethanol and water. The washed product was then dried in a vacuum oven at 60°C for 12 hours, with a centrifuge speed of 8000 r / min and a centrifugation time of 5 minutes. The dried sample was then ground in a mortar to obtain a white powder. Finally, the white powder was placed in a crucible and placed in a muffle furnace, heated to 950°C at a heating rate of 5°C / min, and calcined for 3 hours to obtain the SrTiO3 photocatalyst material.

[0045] The photocatalysts prepared in Examples 1-2 of this invention were characterized, and the results are as follows: Figure 1 This is a SEM image of TiO2 with high exposure {001} crystal form prepared in Example 1 of the present invention. It can be observed from the image that the TiO2 with high exposure {001} crystal form prepared has a plate-like morphology with a length and width of about 80 nm and a thickness of about 10 nm. Figure 2 This is a SEM image of the SrTiO3 photocatalytic material prepared from TiO2 with high exposure {001} crystal form in Example 2 of the present invention. It can be seen from the image that the prepared strontium titanate has a cubic structure with uneven size.

[0046] Figure 3 This is the X-ray powder diffraction pattern of the TiO2 precursor with high exposure {001} crystal form prepared in Example 1 of the present invention; Figure 4 This is the X-ray powder diffraction pattern of the SrTiO3 photocatalytic material prepared in Example 2 of this invention; from Figure 3 and Figure 4 The XRD pattern shows that TiO2 with high exposure {001} crystal form was successfully prepared, and SrTiO3 photocatalytic material was also successfully derived.

[0047] The catalysts prepared in Examples 1-3 and Comparative Examples 1-3 of this invention were used for photocatalytic water splitting performance testing. Before performance evaluation, all catalysts were pretreated by photodepositing a certain mass percentage of co-catalyst (0.1 wt% Rh, 0.05 wt% Cr, 0.05 wt% Co). For performance evaluation, 50 mg of the prepared SrTiO3 photocatalyst powder was placed in a photocatalytic reactor containing 50 mL of deionized water and connected to a photocatalytic performance evaluation instrument. Before the photocatalytic reaction, the system was evacuated to remove air, and the photocatalytic water splitting performance was tested under a 300 W xenon lamp (full spectrum). The product content was analyzed by online gas chromatography equipped with a TCD detector.

[0048] Figure 5 This is a comparison chart of the overall water-splitting performance of the SrTiO3 photocatalytic materials obtained in Examples 1-3 and Comparative Examples 1-3 of this invention. The chart shows that the overall water-splitting performance of Examples 1-3 is better than that of Comparative Examples 1-3. This indicates that the SrTiO3 photocatalytic material prepared from TiO2 with high exposure {001} crystal form has higher overall water-splitting performance than SrTiO3 photocatalytic materials prepared by conventional methods and other commercial TiO2, demonstrating the effectiveness and superiority of the preparation method of this invention.

[0049] Finally, it should be noted that the above embodiments do not limit the present invention in any way. Those skilled in the art can make modifications and improvements based on the present invention. Therefore, any modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed by the present invention.

Claims

1. A high-exposure crystal form-derived SrTiO3 photocatalytic material based on TiO2, characterized in that, The SrTiO3 photocatalytic material is derived by using the highly exposed {001} crystal form of TiO2 as the titanium source and soluble strontium salt as the strontium source.

2. The SrTiO3 photocatalytic material according to claim 1, characterized in that, The preparation method of the high-exposed {001} crystal form of TiO2 is as follows: Tetrabutyl titanate and hydrofluoric acid are mixed evenly, and then a hydrothermal reaction is carried out. After the reaction is completed, the mixture is centrifuged, washed, and dried to obtain a white powder of TiO2 with a high-exposed {001} crystal form.

3. The SrTiO3 photocatalytic material according to claim 2, characterized in that, The volume ratio of tetrabutyl titanate to hydrofluoric acid is 5.5-8.5:

1.

4. The SrTiO3 photocatalytic material according to claim 2, characterized in that, The hydrothermal reaction temperature is 150-180℃, and the hydrothermal reaction time is 24-48h.

5. The method for preparing the SrTiO3 photocatalytic material according to any one of claims 1-4, characterized in that, The process includes the following steps: dissolving highly exposed {001} crystal form TiO2 white powder and soluble strontium salt in deionized water, then adding alkaline solution, stirring evenly, and then carrying out a hydrothermal reaction. After the reaction is completed, cooling to room temperature, centrifuging, washing, drying, and calcining are performed to obtain SrTiO3 photocatalytic material.

6. The preparation method according to claim 5, characterized in that, The molar ratio of the highly exposed {001} crystal form of TiO2 white powder to the soluble strontium salt is 1:1-1.

15.

7. The preparation method according to claim 5, characterized in that, The soluble strontium salt is selected from strontium hydroxide octahydrate, strontium chloride hexahydrate, or strontium acetate.

8. The preparation method according to claim 5, characterized in that, The alkaline solution is selected from sodium hydroxide solution or potassium hydroxide solution, and the concentration of the alkaline solution is 6-10 mol / L.

9. The preparation method according to claim 5, characterized in that, The hydrothermal reaction temperature is 140-180℃, and the hydrothermal reaction time is 12-18h.

10. The application of the SrTiO3 photocatalytic material as described in any one of claims 1-4 in photocatalytic water splitting.

Images