Aluminum-doped strontium titanate loaded with sulfur-zinc-cadmium photocatalytic composite material and preparation method thereof

Abstract

The embodiment of the present disclosure discloses a kind of aluminum-doped strontium titanate loaded sulfur zinc cadmium photocatalytic composite materials and preparation method thereof, the preparation method includes: step S1, aluminum ion is incorporated into strontium titanate using salt melting method, and aluminum-doped strontium titanate is obtained;Step S2, aluminum-doped strontium titanate, cadmium source, zinc source and sulfur source are added to pure water, and precursor solution is obtained after mixing treatment;Step S3, precursor solution is transferred to reaction kettle, and after sealing reaction kettle, it is placed in air drying oven to carry out hydrothermal reaction;Step S4, the precipitate after hydrothermal reaction is treated, and the aluminum-doped strontium titanate loaded sulfur zinc cadmium photocatalytic composite material is obtained.The method can improve the visible light absorption range of strontium titanate and photoelectric conversion efficiency, and improve the photocatalyst photocatalytic water decomposition hydrogen production performance.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of photocatalytic decomposition of water to produce hydrogen, and particularly relates to a photocatalytic composite material of aluminum-doped strontium titanate loaded with sulfur-zinc-cadmium and a preparation method thereof. BACKGROUND

[0002] Simulating photosynthesis to decompose water to produce hydrogen using solar energy is an effective way to develop green, clean and sustainable new energy. Semiconductor materials with high photocatalytic capacity are the key to realizing large-scale photocatalytic decomposition of water to produce hydrogen.

[0003] Strontium titanate is widely used in the field of photocatalysis due to its structural stability, non-toxicity, environmental protection and economic benefits. However, the wide band gap of strontium titanate results in its ability to only utilize a small amount of ultraviolet light in sunlight, which has a low solar utilization rate. In addition, strontium titanate also has a large number of internal defects, which leads to a high recombination rate of its electron-hole pairs and a low photoelectric conversion efficiency. SUMMARY

[0004] Therefore, the present disclosure provides a photocatalytic composite material of aluminum-doped strontium titanate loaded with sulfur-zinc-cadmium and a preparation method thereof, which can improve the solar utilization rate and photoelectric conversion efficiency of strontium titanate, thereby improving the photocatalytic decomposition of water to produce hydrogen performance of strontium titanate.

[0005] In a first aspect, the present disclosure provides a preparation method of a photocatalytic composite material of aluminum-doped strontium titanate loaded with sulfur-zinc-cadmium, which adopts the following technical scheme:

[0006] The preparation method of the photocatalytic composite material of aluminum-doped strontium titanate loaded with sulfur-zinc-cadmium includes:

[0007] Step S1, aluminum ions are doped into strontium titanate by a salt melting method to obtain aluminum-doped strontium titanate;

[0008] Step S2, aluminum-doped strontium titanate, a cadmium source, a zinc source and a sulfur source are added to pure water, and a precursor solution is obtained after mixing treatment;

[0009] Step S3, the precursor solution is transferred to a reaction kettle, the reaction kettle is sealed and then placed in a forced air drying oven for hydrothermal reaction;

[0010] Step S4, the precipitate after the hydrothermal reaction is post-treated to obtain the photocatalytic composite material of aluminum-doped strontium titanate loaded with sulfur-zinc-cadmium.

[0011] In a possible implementation form of the first aspect, the sulfur source in step S2 includes sodium sulfide, and the molar ratio of aluminum-doped strontium titanate to sodium sulfide in the precursor solution is 10:1 to 100:1.

[0012] In a possible implementation of the first aspect, the cadmium source in step S2 includes cadmium acetate, and the zinc source includes zinc acetate, and the molar ratio of cadmium acetate to zinc acetate in the precursor solution is 1-3.

[0013] In a possible implementation of the first aspect, the concentration of the aluminum-doped strontium titanate in the precursor solution in step S1 is 0.008 g / ml-0.025 g / ml.

[0014] In a possible implementation of the first aspect, the mixing treatment in step S2 includes stirring and ultrasonic dispersion.

[0015] In a possible implementation of the first aspect, the temperature of the hydrothermal reaction in step S3 is 100-250 DEG C.

[0016] In a possible implementation of the first aspect, the holding time of the hydrothermal reaction in step S3 is 8-20 h.

[0017] In a possible implementation of the first aspect, step S4 includes: washing the precipitate after the hydrothermal reaction with deionized water; transferring the washed precipitate to a blast drying oven for drying; and grinding the dried precipitate to obtain the aluminum-doped strontium titanate loaded with sulfur-zinc-cadmium photocatalytic composite material.

[0018] In a possible implementation of the first aspect, step S1 includes: grinding and mixing strontium chloride, strontium titanate, and aluminum oxide to obtain a mixed powder; transferring the mixed powder to a muffle furnace for high-temperature treatment to obtain a block-shaped product; and removing strontium chloride from the block-shaped product to obtain the aluminum-doped strontium titanate.

[0019] In a second aspect, the disclosure provides an aluminum-doped strontium titanate loaded with sulfur-zinc-cadmium photocatalytic composite material, which is prepared by the method described above.

[0020] The preparation method of the aluminum-doped strontium titanate loaded with sulfur-zinc-cadmium photocatalytic composite material in the embodiments of the disclosure first uses a salt melting method to dope aluminum ions into strontium titanate to obtain aluminum-doped strontium titanate; then aluminum-doped strontium titanate, a cadmium source, a zinc source, and a sulfur source are added to pure water, and a precursor solution is obtained after mixing treatment; then the precursor solution is transferred to a reaction kettle, the reaction kettle is sealed, and then placed in a blast drying oven for hydrothermal reaction; and finally, the precipitate after the hydrothermal reaction is treated to obtain the aluminum-doped strontium titanate loaded with sulfur-zinc-cadmium photocatalytic composite material. Coating the sulfur-zinc-cadmium on the surface of the strontium titanate can increase the light absorption of the strontium titanate on the one hand by using the narrow band gap and yellow color of the sulfur-zinc-cadmium. On the other hand, a heterojunction can be formed between the strontium titanate and the sulfur-zinc-cadmium to improve the electron-hole pair separation efficiency of the strontium titanate.

[0021] The above description is only a summary of the technical solutions of the present disclosure. In order to make the technical means of the present disclosure more clearly understood, the contents of the specification can be implemented, and in order to make the above and other purposes, characteristics and advantages of the present disclosure more obvious and easy to understand, the following preferred embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0023] Figure 1 The flow chart of the preparation method of the photocatalytic composite material of aluminum-doped strontium titanate loaded with sulfur-zinc-cadmium provided by the embodiments of the present disclosure;

[0024] Figure 2 a~h in the above are scanning electron microscope images provided by the embodiments of the present disclosure;

[0025] Figure 3 The X-ray diffraction spectrum provided by the embodiments of the present disclosure;

[0026] Figure 4 The ultraviolet-visible absorption spectrum provided by the embodiments of the present disclosure;

[0027] Figure 5 The Kubelka-Munk transformation function band gap diagram provided by the embodiments of the present disclosure;

[0028] Figure 6 The change curve of the amount of substance of the photocatalytic decomposition of water to produce hydrogen gas with time provided by the embodiments of the present disclosure;

[0029] Figure 7 The corresponding hydrogen production rate diagram provided by the embodiments of the present disclosure. Figure 6 The corresponding hydrogen production rate diagram. DETAILED DESCRIPTION

[0030] The embodiments of the present disclosure will be described in detail below with reference to the drawings.

[0031] It should be apparent that the following description illustrates by way of example only a number of possible embodiments of the present disclosure and that many of the details provided herein can be varied considerably without departing from the basic principles of the present disclosure. It should be apparent that the described embodiments are merely a small sub-portion of all possible embodiments that can be implemented in accordance with the present disclosure. The present disclosure can be implemented in additional different ways, or with various modifications, and various details can be changed based on different views and applications without departing from the spirit of the present disclosure. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present disclosure.

[0032] It should be apparent that the following description illustrates by way of example only a number of possible embodiments of the present disclosure and that many of the details provided herein can be varied considerably without departing from the basic principles of the present disclosure. It should be apparent that the described embodiments are merely a small sub-portion of all possible embodiments that can be implemented in accordance with the present disclosure. The present disclosure can be implemented in additional different ways, or with various modifications, and various details can be changed based on different views and applications without departing from the spirit of the present disclosure. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present disclosure.

[0033] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, one skilled in the relevant art will appreciate that the described aspects can be practiced without these specific details.

[0034] At present, although strontium titanate is widely used in the field of photocatalytic materials due to its structural stability, non-toxicity, environmental protection and other advantages, because strontium titanate also has the characteristic of wide band gap, it only has absorption capacity for ultraviolet light with low content in sunlight, which reduces its utilization rate of sunlight; in addition, the defects caused by trivalent titanium ions in strontium titanate can accelerate the recombination speed of electron-hole pairs, and reduce its photoelectric conversion efficiency.

[0035] The inventors find that cadmium zinc sulfide is a semiconductor with a relatively narrow band gap and strong light absorption. Coating cadmium zinc sulfide on the surface of strontium titanate can increase the light absorption of the photocatalyst and improve the utilization rate of sunlight of the photocatalyst. On the other hand, a heterojunction can be formed between strontium titanate and cadmium zinc sulfide, which can inhibit the recombination of electron-hole pairs and thus improve the photoelectric conversion efficiency of the photocatalyst. Therefore, strontium titanate can be used as a substrate, and cadmium zinc sulfide can be grown on the surface of strontium titanate. The strong light absorption of cadmium zinc sulfide can increase the light absorption capacity of strontium titanate and improve the visible light utilization rate of strontium titanate. A heterojunction can be constructed at the interface between strontium titanate and cadmium zinc sulfide, which can reduce the recombination rate of electron-hole pairs and thus improve the photoelectric conversion efficiency of aluminum-doped strontium titanate.

[0036] Based on this, the embodiments of the present disclosure provide a kind of aluminum-doped strontium titanate loaded cadmium zinc sulfide photocatalytic composite material and its preparation method, as shown in Figure 1 The preparation method comprises steps S1 to S4.

[0037] In step S1, aluminum ions are doped into strontium titanate by salt melting method to obtain aluminum-doped strontium titanate.

[0038] In this step, Al 3+ can reduce the defects in strontium titanate caused by Ti 3+ , so that the carriers generated when strontium titanate is irradiated can be more transferred to the surface to participate in the decomposition of water to produce hydrogen, showing high photoelectric conversion efficiency.

[0039] In an example, aluminum ions can be doped into strontium titanate by molten salt method. The molten salt method usually uses one or several low-melting salts as reaction medium. The reactants have a certain solubility in the molten salt, so that the reaction proceeds at the atomic level. After the reaction is completed, the salt is dissolved with a suitable solvent, and the synthesized product can be obtained after filtration and washing. Compared with the conventional solid phase method, the molten salt method has the advantages of simple process, low synthesis temperature, short holding time, uniform chemical composition of synthesized powder, good crystal morphology, and high phase purity.

[0040] The strontium titanate doped with aluminum ions by the salt melting method can recrystallize and expose more crystal faces that are beneficial to the catalytic decomposition of water. Compared with directly using strontium titanate as a substrate, using aluminum-doped strontium titanate as a substrate can improve the photocatalytic water decomposition and hydrogen production capacity of strontium titanate.

[0041] Specifically, strontium chloride can be used as a reaction medium. Strontium chloride, strontium titanate and aluminum oxide are ground and mixed to obtain a mixed powder. The mixed powder is transferred to a muffle furnace for high-temperature treatment to obtain a block-shaped product. The block-shaped product is subjected to strontium chloride removal treatment to obtain aluminum-doped strontium titanate.

[0042] Step S2, aluminum-doped strontium titanate, cadmium source, zinc source and sulfur source are added to pure water, and after mixing treatment, a precursor solution is obtained.

[0043] In this step, the mixing treatment includes stirring and ultrasonic dispersion. After adding aluminum-doped strontium titanate, cadmium source, zinc source and sulfur source to pure water, a magnetic stirrer can be used for stirring for 5 min and ultrasonic dispersion for 30 min to fully disperse the agglomerated aluminum-doped strontium titanate into the aqueous solution.

[0044] The sulfur source can include sodium sulfide nonahydrate. The amount-of-substance ratio of aluminum-doped strontium titanate to sodium sulfide nonahydrate can be adjusted to configure the precursor solution, so as to control the mass of the sulfur-zinc-cadmium coating on the strontium titanate. The cadmium source can include cadmium acetate, and the zinc source can include zinc acetate. The amount-of-substance ratio of cadmium acetate to zinc acetate can be adjusted to change the morphology and performance of the aluminum-doped strontium titanate.

[0045] Exemplarily, the amount-of-substance ratio of aluminum-doped strontium titanate to sodium sulfide nonahydrate in the precursor solution is 10:1 to 100:1. Exemplarily, the amount-of-substance ratio of cadmium acetate to zinc acetate in the precursor solution is 1 to 3. The concentration of aluminum-doped strontium titanate in the precursor solution is 0.008 g / ml to 0.025 g / ml. The mass of the sulfur-zinc-cadmium coating on the strontium titanate in the above range is moderate, and the sulfur-zinc-cadmium coating with a suitable thickness can form a heterojunction with the strontium titanate, so as to form an internal electric field at the heterojunction interface to improve the separation and transfer speed of electron-hole pairs, thereby realizing high-efficiency photocatalytic water splitting to produce hydrogen. However, excessive loading of sulfur-zinc-cadmium can cause a shielding effect to reduce the light absorption of the photocatalyst.

[0046] Step S3, the precursor solution is transferred to a reaction kettle, the reaction kettle is sealed and then placed in a forced air drying oven for hydrothermal reaction.

[0047] The lining material in the reaction kettle can be polytetrafluoroethylene, which is corrosion-resistant, high-pressure-resistant and high-temperature-resistant. Exemplarily, a stainless steel autoclave can be used as the reaction kettle. After the stainless steel autoclave is placed in a forced air drying oven and heated and kept warm, a powdery precipitate is obtained.

[0048] Exemplarily, the temperature of the hydrothermal reaction can be 100℃ to 250℃, and the holding time can be 8h to 20h. The sulfur-zinc-cadmium will recrystallize and grow on the surface of the strontium titanate. The holding time and the holding temperature both have an effect on the growth of the sulfur-zinc-cadmium. The longer the holding time, the larger the crystal grain size. When the holding time exceeds 12h, part of the crystal faces of the sulfur-zinc-cadmium will disappear. Therefore, the optimal holding time is 12h. The higher the holding temperature, the higher the crystallinity. When the holding temperature exceeds 160℃, the crystallinity does not change significantly. Therefore, the optimal holding temperature is 160℃.

[0049] Step S4, the precipitate after the hydrothermal reaction is post-treated to obtain a photocatalytic composite material of aluminum-doped strontium titanate loaded with sulfur-zinc-cadmium.

[0050] The post-processing process can include: cleaning the precipitate after the hydrothermal reaction with deionized water; transferring the cleaned precipitate to a blast drying oven for drying to remove moisture; and grinding the dried precipitate to disperse the powder and reduce agglomeration, thereby obtaining the photocatalytic composite material of aluminum-doped strontium titanate loaded with nickel sulfide.

[0051] As described above, in the method for preparing the photocatalytic composite material of aluminum-doped strontium titanate loaded with sulfur zinc cadmium, the aluminum ions are first doped into strontium titanate by using a salt melting method to obtain aluminum-doped strontium titanate. Then, the aluminum-doped strontium titanate, a cadmium source, a zinc source, and a sulfur source are added to pure water, and a precursor solution is obtained after mixing. The precursor solution is then transferred to a reaction kettle, which is sealed and placed in a blast drying oven for hydrothermal reaction. Finally, the precipitate after the hydrothermal reaction is post-processed to obtain the photocatalytic composite material of aluminum-doped strontium titanate loaded with sulfur zinc cadmium. Coating the sulfur zinc cadmium on the surface of the strontium titanate can increase the light absorption of the photocatalyst and improve the utilization rate of sunlight by the photocatalyst. On the other hand, a heterojunction can be formed between the strontium titanate and the sulfur zinc cadmium, which can inhibit the recombination of photo-generated carriers and reduce the recombination rate of electron-hole pairs, thereby improving the photoelectric conversion efficiency of the aluminum-doped strontium titanate and the photocatalytic water splitting hydrogen production capacity of the photocatalyst.

[0052] The present disclosure also provides a photocatalytic composite material of aluminum-doped strontium titanate loaded with sulfur zinc cadmium, which is prepared by the above method.

[0053] To make the technical personnel in the art more clearly understand the performance advantages of the photocatalytic composite material of aluminum-doped strontium titanate loaded with nickel sulfide in the embodiments of the present disclosure, the embodiments of the present disclosure are described below with specific examples. Wherein, SA represents aluminum-doped strontium titanate, CZS (CdZnS) represents sulfur zinc cadmium, SrTiO3: Al represents aluminum-doped strontium titanate, and SACZSx% represents x% of the amount of substance of sulfur zinc cadmium coated aluminum-doped strontium titanate. Example 1

[0054] This example 1 is used to prepare SA.

[0055] Take 8g strontium titanate, 0.088g aluminum oxide, 69.112g strontium chloride, mix and put into agate mortar, grind for 2 hours; pour the well-grounded mixed powder into a 99.2% alumina square crucible with a volume of 510ml, then put the crucible into the muffle furnace, heat to 1150℃ at a heating rate of 10℃ / min, and keep for 10h. Among them, the aluminum source can be provided by aluminum oxide and aluminum oxide crucible together. Then take out after cooling from room temperature; at this time the sample is in solid block shape, take out the solid block and put it into a beaker, add 80℃ deionized water to wash the sample, dissolve the strontium chloride wrapped in strontium titanate into water, hot water can accelerate the dissolution of strontium chloride, then stand for a period of time, the solution is divided into two layers, take out the upper layer and pour it away, repeat the cleaning of the lower layer for 10 times, completely remove the strontium chloride; put the cleaned precipitate into a beaker and put it into a forced air drying oven at 80℃ for 3 hours to remove the water; put the dried sample into an agate mortar and grind for 10min, then put it into a sealed tube for storage, and get a light yellow white micron SA powder. Example 2

[0056] This example 2 is used to prepare SACZS1%.

[0057] Take 1g SA, 0.009g cadmium acetate, 0.005g zinc acetate and 0.013g sodium sulfide nine hydrate into 60ml deionized water, stir for 5min with a magnetic stirrer, ultrasonic dispersion for 30min, pour into a 100ml polytetrafluoroethylene reactor liner after stirring evenly; put the reactor liner into a stainless steel high-pressure reactor, put it into a forced air drying oven and heat to 160℃, keep for 12h; after the reactor cools down to room temperature, take out the liner, pour the suspension into a beaker; after standing for a period of time, the suspension is layered, pour away the upper layer solution, put the lower layer precipitate into a forced air drying oven and dry at 80℃, then put it into an agate mortar and grind for 5min, put it into a sealed tube for storage, and get a light yellow SACZS1% powder. Example 3

[0058] This example 3 is used to prepare SACZS3%.

[0059] Take 1g SA, 0.026g cadmium acetate, 0.014g zinc acetate and 0.039g sodium sulfide nine hydrate into 60ml deionized water, stir for 5min with a magnetic stirrer, ultrasonic dispersion for 30min, pour into a 100ml polytetrafluoroethylene reactor liner after stirring evenly; put the reactor liner into a stainless steel high-pressure reactor, put it into a forced air drying oven and heat to 160℃, keep for 12h; after the reactor cools down to room temperature, take out the liner, pour the suspension into a beaker; after standing for a period of time, the suspension is layered, pour away the upper layer solution, put the lower layer precipitate into a forced air drying oven and dry at 80℃, then put it into an agate mortar and grind for 5min, put it into a sealed tube for storage, and get a light yellow SACZS3%. Example 4

[0060] Example 4 is used to prepare SACZS5%.

[0061] Take 1 g SA, 0.044 g cadmium acetate, 0.024 g zinc acetate and 0.065 g sodium sulfide nine hydrate into 60 ml deionized water, stir for 5 min using a magnetic stirrer, ultrasonic dispersion for 30 min, pour into a 100 ml polytetrafluoroethylene reactor liner after stirring evenly; Put the reactor liner into a stainless steel high-pressure reactor, put it into a forced air drying oven and heat to 160°C, and keep it for 12 hours; After the reactor cools to room temperature, take out the liner, pour the suspension into a beaker; After standing for a period of time, the suspension is layered, the upper solution is poured off, and the lower precipitate is dried in a forced air drying oven at 80°C, then put into a agate mortar and grind for 5 min, put into a sealed tube for storage, get SACZS5%. Example 5

[0062] Example 5 is used to prepare SACZS7%.

[0063] Take 1 g SA, 0.062 g cadmium acetate, 0.034 g zinc acetate and 0.093 g sodium sulfide nine hydrate into 60 ml deionized water, stir for 5 min using a magnetic stirrer, ultrasonic dispersion for 30 min, pour into a 100 ml polytetrafluoroethylene reactor liner after stirring evenly; Put the reactor liner into a stainless steel high-pressure reactor, put it into a forced air drying oven and heat to 160°C, and keep it for 12 hours; After the reactor cools to room temperature, take out the liner, pour the suspension into a beaker; After standing for a period of time, the suspension is layered, the upper solution is poured off, and the lower precipitate is dried in a forced air drying oven at 80°C, then put into a agate mortar and grind for 5 min, put into a sealed tube for storage, get SACZS7%. Example 6

[0064] Example 6 is used to prepare SACZS9%.

[0065] Take 1 g SA, 0.062 g cadmium acetate, 0.034 g zinc acetate and 0.093 g sodium sulfide nine hydrate into 60 ml deionized water, stir for 5 min using a magnetic stirrer, ultrasonic dispersion for 30 min, pour into a 100 ml polytetrafluoroethylene reactor liner after stirring evenly; Put the reactor liner into a stainless steel high-pressure reactor, put it into a forced air drying oven and heat to 160°C, and keep it for 12 hours; After the reactor cools to room temperature, take out the liner, pour the suspension into a beaker; After standing for a period of time, the suspension is layered, the upper solution is poured off, and the lower precipitate is dried in a forced air drying oven at 80°C, then put into a agate mortar and grind for 5 min, put into a sealed tube for storage, get SACZS7%. Example 7

[0066] Example 7 is used to prepare SACZS10.

[0067] Take 1g SA, 0.087g cadmium acetate, 0.048g zinc acetate, and 0.131g sodium sulfide nonahydrate and add them to 60ml deionized water. Stir with a magnetic stirrer for 5min, then sonicate for 30min. After stirring evenly, pour the mixture into a 100ml polytetrafluoroethylene (PTFE) reactor liner. Place the reactor liner into a stainless steel high-pressure reactor and heat it to 160℃ in a forced-air drying oven for 12h. After the reactor cools to room temperature, remove the liner and pour the suspension into a beaker. After standing for a period of time, the suspension separates into layers. Discard the upper layer and dry the lower precipitate in a forced-air drying oven at 80℃. Grind the precipitate in an agate mortar for 5min and store it in a sealed tube to obtain SACZS10%. Example 8

[0068] Example 8 is used to prepare CZS.

[0069] Take 3.998g of cadmium acetate, 2.195g of zinc acetate, and 6.004g of sodium sulfide nonahydrate and add them to 60ml of deionized water. Stir with a magnetic stirrer for 5 minutes and ultrasonically disperse for 30 minutes. After stirring evenly, pour the mixture into a 100ml polytetrafluoroethylene (PTFE) reactor liner. Place the reactor liner into a stainless steel high-pressure reactor and heat it to 160℃ in a forced-air drying oven for 12 hours. After the reactor cools to room temperature, remove the liner and pour the suspension into a beaker. After standing for a period of time, the suspension separates into layers. Discard the upper layer and dry the lower precipitate in a forced-air drying oven at 80℃. Grind the precipitate in an agate mortar for 5 minutes and store it in a sealed tube to obtain orange-yellow CZS.

[0070] The performance of SA, SACZSx%, and CZS prepared in Examples 1 to 8 above will be analyzed below.

[0071] Figure 2 In the figures a~h, the images are scanning electron microscope images provided in the embodiments of this disclosure. Figure 2 Images a through h show scanning electron microscope (SEM) images of SA, CZS, SACZS1%, SACZS3%, SACZS5%, SACZS7%, SACZS9%, and SACZS10%, respectively.

[0072] from Figure 2 As can be seen from a, SA is composed of nanoflowers made up of nanosheets and micron-sized particles; from Figure 2 As can be seen from b, zinc cadmium sulfate is composed of nano-sized particles aggregated together; Figure 2In the middle c-h, it is also shown that the cadmium zinc sulfide nanoparticles are attached to the surface of strontium titanate, which indicates that the cadmium zinc sulfide grows on the strontium titanate successfully, and the loading rate of cadmium zinc sulfide on the strontium titanate increases with the increase of the content of cadmium zinc sulfide.

[0073] Figure 3 The X-ray diffraction spectrum provided by the embodiment of the present disclosure. Figure 3 The X-ray diffraction spectra of SA, CZS, SACZS1%, SACZS3%, SACZS5%, SACZS7%, SACZS9%, and SACZS10% are shown. In all curves, the characteristic diffraction peaks of strontium titanate are detected at 2 of 22.7°, 32.4°, 40°, 46.4°, 52.5°, 57.7°, 67.8°, and 77.2°, which are consistent with the (100), (110), (111), (200), (210), (211), (300) crystal planes of cubic strontium titanate. The characteristic diffraction peaks of strontium titanate can be observed in all samples; in all samples, the characteristic peaks of CZS at 2 of 25.5, 27.1, 28.8, 44.8, and 52.8 corresponding to the (100), (002), (101), (110), and (201) crystal planes of cadmium zinc sulfide can be detected. The results show that cadmium zinc sulfide is successfully loaded on SrTiO3:Al.

[0074] Figure 4 The ultraviolet-visible absorption spectrum provided by the embodiment of the present disclosure, Figure 4 In the middle a~h, the ultraviolet-visible light absorption spectra of SA, CZS, SACZS1%, SACZS3%, SACZS5%, SACZS7%, SACZS9%, and SACZS10% are shown.

[0075] From Figure 4 It can be seen that, in the 300nm-520nm waveband, CZS has strong light absorption intensity, and the light absorption intensity of SACZSx% increases with the increase of x, which indicates that the loading of cadmium zinc sulfide can effectively improve the light absorption capacity of strontium titanate.

[0076] Figure 5 The Kubelka-Munk transformation function band gap diagram provided by the embodiment of the present disclosure, wherein a~h are respectively the Kubelka-Munk transformation function band gap curves of SA, CZS, SACZS1%, SACZS3%, SACZS5%, SACZS7%, SACZS9%, and SACZS10%.

[0077] From Figure 5As can be seen, the band gap of SA is the largest, the band gap of CZS is the smallest, and the band gap of SACZS gradually narrows with the increase of the load of sulfur zinc cadmium, indicating that the sulfur zinc cadmium and the SrTiO3:Al interface contact closely to form a heterojunction, which is conducive to promoting the separation and transfer of photo-generated carriers.

[0078] In addition, the present embodiment also tests the change curve of the amount of substance of hydrogen generated by photocatalytic decomposition of water of SA, CZS, SACZS1%, SACZS3%, SACZS5%, SACZS7%, SACZS9% and SACZS10% over time. The test steps are as follows:

[0079] (1) 0.2g of the sample to be tested, 4.4g of anhydrous sodium sulfite and 6.0g of sodium sulfide nine hydrate are added into 100ml of deionized water to form a suspension by ultrasonic for half an hour; the suspension is poured into a top-illumination type light reactor, the reactor is connected with a photocatalytic hydrogen production reaction system, a circulating refrigerator is opened and set to 6℃, a magnetic stirrer is opened and set to 500r / min, and a vacuum pump is opened and vacuumized for 30min.

[0080] (2) A large lifting platform is taken to make the distance between the lifting platform and the table top be 31cm, a 300W xenon lamp with an AM1.5G filter is placed on the large lifting platform, the light source is directly opposite to the upper part of the reactor, the xenon lamp is turned on, and the light intensity of the liquid surface is measured to be 1000 W / m 2 ;

[0081] (3) The gas chromatograph is opened, the gas chromatograph is connected to a computer, and a TCD detector is set.

[0082] (4) The xenon lamp is turned on, and the sample is taken to the gas chromatograph for analysis every 1h.

[0083] Figure 6 The change curve of the amount of substance of hydrogen generated by photocatalytic decomposition of water of SA, CZS, SACZS1%, SACZS3%, SACZS5%, SACZS7%, SACZS9% and SACZS10% over time provided by the embodiment of the present disclosure is used to represent the change curve of the amount of substance of hydrogen generated by photocatalytic decomposition of water of SA, CZS, SACZS1%, SACZS3%, SACZS5%, SACZS7%, SACZS9% and SACZS10% over time, Figure 7 corresponding to Figure 6 the hydrogen production rate graph.

[0084] From Figure 6It can be seen that the amount of substance of hydrogen generated by SACZSx% increases first with the increase of x, reaches the maximum when x is equal to 7, and then decreases, which indicates that loading a certain amount of sulfur zinc cadmium can improve the photocatalytic water splitting hydrogen production capacity of the sample, but loading an excessive amount of sulfur zinc cadmium will reduce the photocatalytic water splitting hydrogen production capacity of the sample, due to the fact that the excessive sulfur zinc cadmium is loosely distributed around strontium titanate, and does not form a heterojunction with strontium titanate, and strontium titanate and the excessive sulfur zinc cadmium are only physically combined.

[0085] From Figure 7 It can be seen that the hydrogen production rate of SACZS7% is the highest, which is 75.6 times and 1.9 times higher than that of SA and CZS respectively. Moreover, the hydrogen production rate of the sample with a sulfur zinc cadmium molar loading concentration greater than or equal to 5% is higher than that of sulfur zinc cadmium and aluminum-doped strontium titanate. This indicates that a heterojunction is formed between sulfur zinc cadmium and SrTiO3:Al, the separation rate of the overall catalyst electron-hole pairs is improved, and excellent photocatalytic water splitting hydrogen production capacity is exhibited.

[0086] In summary, SACZS7% has more excellent photocatalytic water splitting hydrogen production capacity than SA and CZS, and is a photocatalytic water splitting hydrogen production material with great potential.

[0087] The detailed description of the present embodiment can refer to the corresponding description in the foregoing embodiments, which will not be repeated here.

[0088] The basic principles of the present disclosure are described above in combination with specific embodiments, but it should be noted that the advantages, advantages, effects and the like mentioned in the present disclosure are only examples and are not limiting, and these advantages, advantages, effects and the like cannot be considered as the must-have of each embodiment of the present disclosure. In addition, the above specific details of the disclosure are only for the purpose of example and for the purpose of understanding, and the above details do not limit the disclosure to be necessarily implemented with the above specific details.

[0089] In addition, as used herein, "or" used in the listing of items that start with "at least one" indicates separate listing, so that for example, the listing of "at least one of A, B or C" means A or B or C, or AB or AC or BC, or ABC (i.e. A and B and C). In addition, the phrase "exemplary" does not mean that the described example is preferred or better than other examples.

[0090] It should also be noted that in the systems and methods of the present disclosure, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be considered as equivalent solutions of the present disclosure.

[0091] Various changes, modifications, and alterations to the techniques described herein can be made without departing from the teachings of the attached claims. Moreover, the scope of the claims of this disclosure is not limited to the particular aspects described above. In addition, where a process, machine, manufacture, composition of matter, means, method, or result containing procedural, business, and other steps is described, it is understood that the description is meant to encompass the specific implementation of the steps described, as well as the substitution of equivalent steps, or equivalent steps in the performance order. Accordingly, the attached claims are to be interpreted as embracing the specific aspects and embodiments described herein, as well as future modifications, changes, and alterations of the aspects and embodiments.

[0092] The above description of the disclosed aspects is given to enable any person skilled in the art to make or use the disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other aspects without departing from the scope of the disclosure. Thus, the present disclosure is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0093] The above description has been given for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present disclosure to forms disclosed herein. Although various example aspects and embodiments have been discussed above, those of ordinary skill in the art will appreciate a variety of modifications, alternatives, permutations, additions, and sub-combinations of the aspects and embodiments described above.

Claims

1. The use of a photocatalytic composite material of aluminum-doped strontium titanate loaded with zinc sulfide and cadmium in the photocatalytic decomposition of water to produce hydrogen, characterized in that, The preparation method of the photocatalytic composite material comprises the following steps: S1, aluminum ions are doped into strontium titanate by a salt melting method to obtain aluminum-doped strontium titanate; S2, aluminum-doped strontium titanate, a cadmium source, a zinc source and a sulfur source are added to pure water, and a precursor solution is obtained after mixing treatment; S3, the precursor solution is transferred to a reaction kettle, the reaction kettle is sealed and then placed in a blast drying oven for hydrothermal reaction; S4, the precipitate after the hydrothermal reaction is post-treated to obtain a photocatalytic composite material SACZS7% of aluminum-doped strontium titanate loaded with sulfur zinc cadmium, wherein SA represents aluminum-doped strontium titanate, CZS represents sulfur zinc cadmium, and SACZS7% represents 7% of the amount of substance of sulfur zinc cadmium coated aluminum-doped strontium titanate; The step S1 comprises: The strontium chloride, strontium titanate and aluminum oxide are ground and mixed to obtain a mixed powder; The mixed powder is transferred to a muffle furnace for high-temperature treatment to obtain a block-shaped product; The block-shaped product is subjected to strontium chloride removal treatment to obtain aluminum-doped strontium titanate; The sulfur source in the step S2 comprises sodium sulfide nine hydrate, and the amount-of-substance ratio of aluminum-doped strontium titanate to sodium sulfide nine hydrate in the precursor solution is 10:1-100:

1.

2. Use of the photocatalytic composite material according to claim 1 for photocatalytic decomposition of water to produce hydrogen, characterized in that, The cadmium source in the step S2 comprises cadmium acetate, and the zinc source comprises zinc acetate, and the amount-of-substance ratio of cadmium acetate to zinc acetate in the precursor solution is 1-3.

3. Use of the photocatalytic composite material according to claim 1 for photocatalytic decomposition of water for hydrogen production, characterized in that, The concentration of aluminum-doped strontium titanate in the precursor solution in the step S2 is 0.008 g / ml-0.025 g / ml.

4. Use of the photocatalytic composite material according to claim 1 in the photocatalytic decomposition of water to produce hydrogen, characterized in that, The mixing treatment in the step S2 comprises stirring and ultrasonic dispersion.

5. Use of the photocatalytic composite material according to claim 1 for photocatalytic decomposition of water for hydrogen production, characterized in that, The temperature of the hydrothermal reaction in the step S3 is 100-250 DEG C.

6. Use of the photocatalytic composite material according to claim 1 for photocatalytic decomposition of water for hydrogen production, characterized in that, The holding time of the hydrothermal reaction in the step S3 is 8-20 h.

7. Use of the photocatalytic composite material according to claim 1 for photocatalytic decomposition of water for hydrogen production, characterized in that, The step S4 comprises: The precipitate after the hydrothermal reaction is washed with deionized water; The washed precipitate is transferred to a blast drying oven for drying; The dried precipitate is ground to obtain a photocatalytic composite material of aluminum-doped strontium titanate loaded with sulfur zinc cadmium.

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