Method for efficiently preparing nano material by photo-assisted hydrothermal / solvothermal method

Abstract

The invention belongs to the technical field of material synthesis, and particularly relates to a method for efficiently preparing a nano material through a photo-assisted hydrothermal / solvothermal method. The photochemical reaction and the hydrothermal / solvothermal reaction are combined, illumination is introduced in the hydrothermal / solvothermal reaction process, reactants are selectively excited through illumination to enter an excited state, and the reaction progress is accelerated along a specific reaction path. Compared with the prior art, the innovative combination of the invention not only overcomes the defect that the traditional hydrothermal / solvothermal method needs long-time high-temperature treatment and the like, but also obviously improves the reaction efficiency and precision, the product is uniform in morphology and size and high in quality, and meanwhile, the stability of the product as a catalyst is improved; the method realizes efficient material synthesis and accurate reaction control, has a wide application prospect, and particularly has a better prospect in the fields of photocatalysis or energy storage and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of material synthesis, and particularly relates to a method for efficiently preparing nanomaterials by a photo-assisted hydrothermal / solvothermal method. Background Art

[0002] As a commonly used material synthesis method, the hydrothermal / solvothermal method is widely used for preparing nanomaterials and functional materials. However, the traditional hydrothermal / solvothermal synthesis method usually requires high-temperature treatment for a long time, the reaction conditions are relatively complex to control, and the process stability is poor.

[0003] With the large-scale application of the hydrothermal / solvothermal method, the problem of non-uniformity of the product morphology and size caused by the above limitations has become increasingly prominent, and has become the main obstacle to its application. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for efficiently preparing nanomaterials by a photo-assisted hydrothermal / solvothermal method. The method provided by the present invention has uniform product morphology and size, and high product quality.

[0005] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a method for efficiently preparing nanomaterials by a photo-assisted hydrothermal / solvothermal method, comprising the following steps:

[0007] Mix a metal salt, an organic amine, and a semiconductor element in the presence of light and carry out a hydrothermal / solvothermal reaction to obtain an organic-inorganic hybrid nanomaterial; the temperature of the hydrothermal / solvothermal reaction is 80-160 °C, and the heat preservation reaction time is 0.5-3 h.

[0008] Preferably, the intensity of the light is 100-400 mW / cm 2 .

[0009] Preferably, the hydrothermal / solvothermal reaction is carried out in a protective atmosphere.

[0010] Preferably, air evacuation is also included before the hydrothermal / solvothermal reaction.

[0011] Preferably, the metal salt is an organometallic salt; the organometallic salt includes one or more of an organic cadmium salt and an organic zinc salt.

[0012] Preferably, the organic amine is diethylenetriamine.

[0013] Preferably, the semiconductor element includes one or two of selenium and sulfur.

[0014] Preferably, the mass ratio of the metal salt to the organic amine is 219-267:38400.

[0015] Preferably, the molar ratio of the metal salt to the elemental semiconductor is 99.9 - 100.1:99.9 - 100.1.

[0016] Preferably, the mixing is carried out by alternately performing ultrasonic treatment and stirring; the power of the ultrasonic treatment is not higher than 100 W; the time for each ultrasonic treatment is 2 - 8 min; the rotation speed of the stirring is 350 - 550 r / min; the time for each stirring is 0.5 - 2 min; the mixing time is 10 - 30 min.

[0017] The present invention provides a method for efficiently preparing nanomaterials by a photo - assisted hydrothermal / solvothermal method. The present invention combines a photochemical reaction with a hydrothermal / solvothermal reaction, introduces light irradiation during the hydrothermal / solvothermal reaction process, selectively excites the light - absorbable reactant (elemental semiconductor) through light irradiation, enables it to enter the excited state, and accelerates the reduction reaction process of the elemental semiconductor along a specific reaction path, and then reacts with a metal salt - organic amine intermediate (such as 2 (DETA)] 4+ ) to generate a target product with lower crystallinity (nanosized). Compared with the prior art, this innovative combination of the present invention not only overcomes the disadvantages of the traditional hydrothermal / solvothermal method, such as the need for high - temperature treatment for a long time, but also significantly improves the reaction efficiency and precision (uniformity). The product morphology and size are uniform, the product quality is high, and at the same time, the stability of the product as a catalyst is improved, realizing efficient material synthesis and precise reaction control, and having broad application prospects, especially better prospects in the fields of photocatalysis or energy storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 XRD patterns of the organic - inorganic hybrid nanomaterials in Examples 1 - 3 and Comparative Examples 1 - 6;

[0020] Figure 2 SEM morphology diagrams of the organic - inorganic hybrid nanomaterials in Examples 1 - 3 and Comparative Examples 1 - 6;

[0021] Figure 3 Hydrogen production performance diagrams of the organic - inorganic hybrid nanomaterials in Example 1, Comparative Example 1, and Comparative Example 4;

[0022] Figure 4Hydrogen production performance diagrams of the organic-inorganic hybrid nanomaterials in Example 2, Comparative Example 2, and Comparative Example 5;

[0023] Figure 5 Hydrogen production performance diagrams of the organic-inorganic hybrid nanomaterials in Example 3, Comparative Example 3, and Comparative Example 6. Detailed implementation manners

[0024] The present invention provides a method for efficiently preparing nanomaterials by a photo-assisted hydrothermal / solvothermal method, comprising the following steps:

[0025] Mix a metal salt, an organic amine, and a semiconductor element and conduct a hydrothermal / solvothermal reaction under light irradiation conditions to obtain an organic-inorganic hybrid nanomaterial.

[0026] In the present invention, a metal salt, an organic amine, and a semiconductor element are mixed (denoted as the first mixing). In the present invention, the metal salt is preferably an organometallic salt; the organometallic salt preferably includes one or more of an organic cadmium salt and an organic zinc salt; the organic cadmium salt is preferably Cd(CH 3 COO) 2 ·2H 2 O; the organic zinc salt is preferably Zn(CH 3 COO) 2 ·2H 2 O.

[0027] In the present invention, the organic amine is preferably an unsaturated organic amine; the unsaturated organic amine is preferably diethylenetriamine (DETA). The organic amine mainly plays two roles. On the one hand, it forms an intermediate product such as [Cd 2 (DETA)] 4+ , and on the other hand, it acts as a sacrificial agent to consume the holes generated after the semiconductor element is irradiated by light, and the generated electrons are used to reduce the semiconductor element to an anion.

[0028] In the present invention, the mass ratio of the metal salt to the organic amine is preferably 219-267:38400, specifically, it can be 219.51:38400, 229:38400, 243.03:38400, 253:38400, or 266.53:38400.

[0029] In the present invention, the semiconductor element preferably includes one or two of selenium (Se) and sulfur (S).

[0030] In the present invention, the molar ratio of the metal salt to the semiconductor element is preferably 99.9-100.1:99.9-100.1, specifically, it can be 99.9:99.9, 99.9:100, 99.9:100.1, 100:99.9, 100:100.1, 100.1:99.9, or 100.1:100.

[0031] In the present invention, the first mixing is preferably as follows: premix a metal salt and an organic amine to obtain a premix, and then mix the premix with a semiconductor element.

[0032] In the present invention, the first mixing is preferably carried out by alternately performing ultrasonic treatment and stirring; the power of the ultrasonic treatment is preferably not higher than 100 W, and specifically can be 50 W or 80 W; the time of each ultrasonic treatment is preferably 2 - 8 min, and specifically can be 4 min or 6 min; the rotation speed of the stirring is preferably 350 - 550 r / min, and specifically can be 450 r / min; the time of each stirring is preferably 0.5 - 2 min, and specifically can be 1 min or 1.5 min; the number of times of alternately performing ultrasonic treatment and stirring (one ultrasonic treatment and one stirring are recorded as one time of alternately performing ultrasonic treatment and stirring) is preferably 2 - 8 times, and specifically can be 4 times or 6 times; the mixing time is preferably 10 - 30 min, and specifically can be 20 min. Through the first mixing in the present invention, the raw materials are fully dissolved, facilitating the subsequent reaction.

[0033] After the mixing, the present invention performs a hydrothermal / solvothermal reaction under light conditions to obtain an organic-inorganic hybrid nanomaterial. In the present invention, the intensity of the light is preferably 100 - 400 mW / cm 2 , and specifically can be 100 mW / cm 2 , 150 mW / cm 2 , 200 mW / cm 2 , 250 mW / cm 2 , 300 mW / cm 2 , 350 mW / cm 2 or 400 mW / cm 2 .

[0034] In the present invention, the temperature of the hydrothermal / solvothermal reaction is preferably 80 - 160 °C, and specifically can be 100 °C, 120 °C or 140 °C, and the holding reaction time is preferably 0.5 - 3 h, and specifically can be 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h or 3 h.

[0035] In the present invention, when the metal in the organic-inorganic hybrid nanomaterial includes Zn, the temperature of the hydrothermal / solvothermal reaction is preferably 120 °C, and the holding reaction time is preferably 0.5 h.

[0036] In the present invention, the hydrothermal / solvothermal reaction is preferably carried out in a protective atmosphere; the protective atmosphere is preferably nitrogen; the equipment for the hydrothermal / solvothermal reaction is preferably a visible high-pressure reaction kettle.

[0037] In the present invention, before the hydrothermal / solvothermal reaction, it is preferably further included to exhaust air; the exhaust air is preferably: blowing a protective gas into the reaction kettle and maintaining it for more than 30 minutes. By exhausting air in the present invention, the reaction solution discharges the air inside it.

[0038] In the present invention, after the hydrothermal / solvothermal reaction, it is preferably further included to perform post-treatment; the post-treatment is preferably: cooling the reaction system and then collecting the product; the cooling is preferably natural cooling; the final temperature of the cooling is preferably room temperature.

[0039] In the present invention, after collecting the product, it is preferably further included to wash and then dry the obtained product; the washing is preferably washing with alcohol; the alcohol used for washing with alcohol is preferably ethanol; the number of washing times is preferably more than 3 times; the drying temperature is preferably 40 - 80 °C, specifically it can be 60 °C, the heat preservation drying time is preferably 8 - 12 h, specifically it can be 10 h; the drying equipment is preferably a vacuum drying oven.

[0040] To further illustrate the present invention, the following combines the attached drawings and embodiments to describe the solution of the present invention in detail, but they cannot be understood as limiting the protection scope of the present invention.

[0041] Example 1

[0042] This example uses a photo-assisted hydrothermal / solvothermal method to prepare an organic-inorganic hybrid nanomaterial, including the following steps:

[0043] First, under light-shielded conditions, 266.53 mg of Cd(CH 3 COO) 2 ·2H 2 O is added to a visible high-pressure reaction kettle containing 40 mL of DETA, and ultrasonic waves and stirring are alternately used until completely dissolved (ultrasonic at 80 W for 8 minutes, stirring at 450 r / min for 2 minutes, and then repeating once); then, 79.97 mg of Se is added to the above visible high-pressure reaction kettle, and N 2 is blown into the visible high-pressure reaction kettle and maintained for 30 minutes to discharge the air in the solution; under a light intensity of 400 mW / cm 2 , the reaction temperature is controlled at 120 °C, the reaction time is 0.5 h, after the reaction ends, it is cooled to room temperature, the product is collected, washed 3 times with ethanol, and dried at 60 °C for 10 h in a vacuum drying oven to obtain an organic-inorganic hybrid nanomaterial, named CdSe-DETA-H-P.

[0044] Example 2

[0045] This example uses a photo-assisted hydrothermal / solvothermal method to prepare an organic-inorganic hybrid nanomaterial, including the following steps:

[0046] First, under light-shielded conditions, 219.51 mg of Zn(CH 3 COO) 2 ·2H 2 O was added to a visible high-pressure reactor containing 40 mL of DETA, and ultrasonic waves and stirring were alternately used until it was completely dissolved (ultrasonic wave at 80 W for 8 min, stirring at 450 r / min for 2 min, and then repeated once); then, 79.97 mg of Se was added to the above visible high-pressure reactor, and N 2 was blown into the visible high-pressure reactor and maintained for 30 min to discharge the air in the solution; under the light intensity of 200 mW / cm 2 the reaction temperature was controlled at 120 °C and the reaction time was 0.5 h. After the reaction ended and cooled to room temperature, the product was collected, washed 3 times with ethanol, and dried in a vacuum drying oven at 60 °C for 10 h to obtain an organic-inorganic hybrid nanomaterial named ZnSe-DETA-H-P.

[0047] Example 3

[0048] In this example, an organic-inorganic hybrid nanomaterial was prepared by a photo-assisted hydrothermal / solvothermal method, including the following steps:

[0049] First, under light-shielded conditions, 133.27 mg of Cd(CH 3 COO) 2 ·2H 2 O and 109.76 mg of Zn(CH 3 COO) 2 ·2H 2 O were added to a visible high-pressure reactor containing 40 mL of DETA, and ultrasonic waves and stirring were alternately used until it was completely dissolved (ultrasonic wave at 80 W for 8 min, stirring at 450 r / min for 2 min, and then repeated once); then, 79.97 mg of Se was added to the above visible high-pressure reactor, and N 2 was blown into the visible high-pressure reactor and maintained for 30 min to discharge the air in the solution; under the light intensity of 400 mW / cm 2 the reaction temperature was controlled at 120 °C and the reaction time was 0.5 h. After the reaction ended and cooled to room temperature, the product was collected, washed 3 times with ethanol, and dried in a vacuum drying oven at 60 °C for 10 h to obtain an organic-inorganic hybrid nanomaterial named Cd 0.5 Zn 0.5 Se-DETA-H-P.

[0050] Comparative Example 1

[0051] The preparation method of this comparative example was the same as that of Example 1, and the only difference was that no light was used, including the following steps:

[0052] First, under light-shielded conditions, 266.53 mg of Cd(CH 3 COO) 2 ·2H 2 O was added to a visible-light high-pressure reactor containing 40 mL of DETA. Ultrasonic waves and stirring were alternated until complete dissolution (ultrasonic waves at 80 W for 8 min, stirring at 450 r / min for 2 min, and then repeated once); then, 79.97 mg of Se was added to the above visible-light high-pressure reactor, and N 2 was blown into the visible-light high-pressure reactor and maintained for 30 min to remove the air in the solution; under a light intensity of 0 mW / cm 2 the reaction temperature was controlled at 120 °C and the reaction time was 0.5 h. After the reaction ended and cooled to room temperature, the product was collected, washed three times with ethanol, and dried in a vacuum drying oven at 60 °C for 10 h to obtain an organic-inorganic hybrid nanomaterial named CdSe-DETA-H.

[0053] Comparative Example 2

[0054] The preparation method of this comparative example was the same as that of Example 2, and the only difference was that no light was used, including the following steps:

[0055] First, under light-shielded conditions, 219.51 mg of Zn(CH 3 COO) 2 ·2H 2 O was added to a visible-light high-pressure reactor containing 40 mL of DETA. Ultrasonic waves and stirring were alternated until complete dissolution (ultrasonic waves at 80 W for 8 min, stirring at 450 r / min for 2 min, and then repeated once); then, 79.97 mg of Se was added to the above visible-light high-pressure reactor, and N 2 was blown into the visible-light high-pressure reactor and maintained for 30 min to remove the air in the solution; under a light intensity of 0 mW / cm 2 the reaction temperature was controlled at 120 °C and the reaction time was 0.5 h. After the reaction ended and cooled to room temperature, the product was collected, washed three times with ethanol, and dried in a vacuum drying oven at 60 °C for 10 h to obtain an organic-inorganic hybrid nanomaterial named ZnSe-DETA-H.

[0056] Comparative Example 3

[0057] The preparation method of this comparative example was the same as that of Example 3, and the only difference was that no light was used, including the following steps:

[0058] First, under light-shielded conditions, 133.27 mg of Cd(CH 3 COO) 2 ·2H 2 O and 109.76 mg of Zn(CH 3COO) 2 ·2H 2 O was added to a visible high-pressure reactor containing 40 mL of DETA, and ultrasonic waves and stirring were alternately used until completely dissolved (ultrasonic at 80 W for 8 min, stirring at 450 r / min for 2 min, and then repeating once); then, 79.97 mg of Se was added to the above visible high-pressure reactor, and N was blown into the visible high-pressure reactor 2 was maintained for 30 min to remove the air in the solution; at a light intensity of 0 mW / cm 2 the reaction temperature was controlled at 120 °C and the reaction time was 0.5 h. After the reaction was completed and cooled to room temperature, the product was collected, washed 3 times with ethanol, and dried at 60 °C in a vacuum drying oven for 10 h to obtain an organic-inorganic hybrid nanomaterial named Cd 0.5 Zn 0.5 Se-DETA-H.

[0059] Comparative Example 4

[0060] In this comparative example, an organic-inorganic hybrid nanomaterial was prepared by a traditional hydrothermal / solvothermal method, including the following steps:

[0061] First, under light-shielded conditions, 266.53 mg of Cd(CH 3 COO) 2 ·2H 2 O was added to a high-pressure reactor containing 40 mL of DETA, and ultrasonic waves and stirring were alternately used until completely dissolved (ultrasonic at 80 W for 8 min, stirring at 450 r / min for 2 min, and then repeating once); then, 79.97 mg of Se was added to the above high-pressure reactor, and N was blown into the high-pressure reactor 2 was maintained for 30 min to remove the air in the solution; the polytetrafluoroethylene high-pressure reactor was transferred to an oven, the reaction temperature was controlled at 140 °C, and the reaction time was 16 h. After the reaction was completed and cooled to room temperature, the product was collected, washed 3 times with ethanol, and dried at 60 °C in a vacuum drying oven for 10 h to obtain an organic-inorganic hybrid nanomaterial named CdSe-DETA-T.

[0062] Comparative Example 5

[0063] In this comparative example, an organic-inorganic hybrid nanomaterial was prepared by a traditional hydrothermal / solvothermal method, including the following steps:

[0064] First, under light-shielded conditions, 219.51 mg of Zn(CH 3 COO) 2 ·2H 2O was added to a high-pressure reactor containing 40 mL of DETA, and ultrasonic waves and stirring were alternately used until it was completely dissolved (ultrasonic wave at 80 W for 8 min, stirring at 450 r / min for 2 min, and then repeated once); then, 79.97 mg of Se was added to the above high-pressure reactor, and N was blown into the high-pressure reactor 2 It was maintained for 30 min to remove the air in the solution; the polytetrafluoroethylene high-pressure reactor was transferred to an oven, the reaction temperature was controlled at 140 °C, and the reaction time was 16 h. After the reaction was completed and cooled to room temperature, the product was collected, washed 3 times with ethanol, and dried at 60 °C in a vacuum drying oven for 10 h to obtain an organic-inorganic hybrid nanomaterial named ZnSe-DETA-T.

[0065] Comparative Example 6

[0066] In this comparative example, a traditional hydrothermal / solvothermal method was used to prepare an organic-inorganic hybrid nanomaterial, including the following steps:

[0067] First, under light-shielded conditions, 133.27 mg of Cd(CH 3 COO) 2 ·2H 2 O and 109.76 mg of Zn(CH 3 COO) 2 ·2H 2 O were added to a high-pressure reactor containing 40 mL of DETA, and ultrasonic waves and stirring were alternately used until it was completely dissolved (ultrasonic wave at 80 W for 8 min, stirring at 450 r / min for 2 min, and then repeated once); then, 79.97 mg of Se was added to the above high-pressure reactor, and N was blown into the high-pressure reactor 2 It was maintained for 30 min to remove the air in the solution; the polytetrafluoroethylene high-pressure reactor was transferred to an oven, the reaction temperature was controlled at 140 °C, and the reaction time was 16 h. After the reaction was completed and cooled to room temperature, the product was collected, washed 3 times with ethanol, and dried at 60 °C in a vacuum drying oven for 10 h to obtain an organic-inorganic hybrid nanomaterial named Cd 0.5 Zn 0.5 Se-DETA-T.

[0068] Test Example 1

[0069] XRD pattern analysis was performed on the organic-inorganic hybrid nanomaterials prepared in Examples 1 to 3 and Comparative Examples 1 to 6. All the test samples were powders. The samples were flattened using a quartz sample stage for sample preparation. The phase structure of the samples was tested using a Bruker D8 Advance X-ray powder diffractometer from Germany. The X-ray source was Kɑ (0.15418 nm) generated by a Cu target filtered by nickel. The test intensity data was collected in the range of 2-Theta angles from 3° to 80°, with a step size of 0.02045° and a pause of 0.1 S at each step. The results are as Figure 1 shown. According to Figure 1 it can be seen that for the organic-inorganic hybrid nanomaterials XSe-DETA-H-P (X can be Cd, Zn, and Cd 0.5 Zn 0.5 ) prepared in the present invention, compared with XSe-DETA-H in Comparative Examples 4 to 6, the diffraction peaks that appear before 10° are relatively low, indicating that the method of the present invention accelerates the reaction rate, reduces the crystallinity of the hybrid material prepared by hydrothermal / solvothermal method, and is more conducive to the formation of nanomaterials.

[0070] Test Example 2

[0071] SEM electron microscopy analysis was performed on the organic-inorganic hybrid nanomaterials prepared in Examples 1 to 3 and Comparative Examples 1 to 6. A small amount of sample powder was dispersed in ethanol or deionized water for dilution and ultrasonic dispersion until it became a colorless and transparent solution. Then it was dropped onto a silicon wafer or a copper sheet and left to air dry, and then transferred to a SIGMA 500 field emission scanning electron microscope of Carl Zeiss Microscopy GmbH to observe the microscopic morphology and size distribution of the samples. The results are as Figure 2 shown. According to Figure 2 a to c in it, it can be seen that the organic-inorganic hybrid nanomaterial CdSe-DETA-H-P prepared by the method of the present invention has a morphology of uniform and relatively thin nanoflower-like; while the hybrid material CdSe-DETA-H formed in Comparative Example 1 under the same conditions but without light has a morphology of agglomerated and relatively thick flower-like; the hybrid material CdSe-DETA-T prepared by the traditional hydrothermal method in Comparative Example 4 shows a non-uniform morphology; according to Figure 2 d to f in it, it can be known that ZnSe-DETA-H-P shows a relatively thin nanoflower-like morphology, and ZnSe-DETA-H and ZnSe-DETA-T show severely agglomerated needle-like morphologies; according to Figure 2 h to g in it, it can be known that Cd 0.5 Zn 0.5 Se-DETA-H-P shows a uniform nanoflower-like morphology, Cd 0.5 Zn 0.5 Se-DETA-H shows an agglomerated nanosheet morphology, Cd 0.5 Zn 0.5Se-DETA-T appears as severely agglomerated needle-like materials; in summary, in the hydrothermal / solvothermal reaction, the introduction of light is more conducive to the formation of nanomaterials.

[0072] Test Example 3

[0073] Using a gas chromatograph (Aulight GC-7920), the photocatalytic water splitting hydrogen production performance of the organic-inorganic hybrid nanomaterials in Example 1, Comparative Example 1, and Comparative Example 4 was tested at 5 °C. The specific test method was as follows: 0.0050 g of the photocatalysts CdSe-DETA-H-P, CdSe-DETA-H, and CdSe-DETA-T were respectively dispersed in 50 mL of 0.25 M Na 2 S and 0.35 M Na 2 SO 3 solution to form a uniform suspension. Then, the above suspension was transferred to a quartz reactor and connected to an online evaluation system (CEL-SPH2N, CEAu Light) with a closed gas circulation. The air in the reactor and the system was removed by vacuum, and a 300 W xenon lamp (Beijing Perfect Light PLS-SXE 300) with a 420 nm cut-off filter was used for photocatalytic hydrogen production testing. Samples were taken once every 30 min, and the generated H 2 gas was detected using a gas chromatograph (Aulight GC-7920) equipped with a thermal conductivity detector (TCD). The test results are as Figure 3 shown.

[0074] According to Figure 3 it can be seen that CdSe-DETA-H-P prepared by the photo-assisted hydrothermal / solvothermal method of the present invention exhibits the best hydrogen production performance. Its hydrogen production rate is 2.53 times that of CdSe-DETA-T and 1.74 times that of CdSe-DETA-H, reaching 9.14 mmol·h -1 ·g -1 .

[0075] Test Example 4

[0076] Using a gas chromatograph (Aulight GC-7920), the photocatalytic water splitting hydrogen production performance of the organic-inorganic hybrid nanomaterials in Example 2, Comparative Example 2, and Comparative Example 5 was tested at 5 °C. The specific test method was as follows:

[0077] 0.0050 g of the photocatalysts ZnSe-DETA-H-P, ZnSe-DETA-H, and ZnSe-DETA-T were respectively dispersed in 50 mL of 0.25 M Na 2 S and 0.35 M Na 2 SO 3In the solution, a uniform suspension was formed. Then, the above suspension was transferred to a quartz reactor and connected to an on-line evaluation system (CEL-SPH2N, CEAu Light) with a closed gas circulation. The air in the reactor and the system was removed by vacuum, and photocatalytic hydrogen production tests were carried out using a 300 W xenon lamp (Beijing PerfectLight PLS-SXE 300). Samples were taken once every 30 min, and the generated H 2 gas was detected using a gas chromatograph (Aulight GC-7920) equipped with a thermal conductivity detector (TCD). The test results are as Figure 4 shown.

[0078] According to Figure 4 it can be seen that ZnSe-DETA-H-P prepared by the photo-assisted hydrothermal / solvothermal method in the present invention exhibits the best hydrogen production performance. Its hydrogen production rate is 2.03 times that of ZnSe-DETA-T and 4.53 times that of ZnSe-DETA-H, reaching 1.17 mmol·h -1 ·g -1 .

[0079] Test Example 5

[0080] Using a gas chromatograph (Aulight GC-7920), the photocatalytic water splitting hydrogen production performance of the organic-inorganic hybrid nanomaterials in Example 3, Comparative Example 3 and Comparative Example 6 was tested at 5 °C. The specific test method was as follows:

[0081] 0.0050 g of the photocatalysts Cd 0.5 Zn 0.5 Se-DETA-H-P, Cd 0.5 Zn 0.5 Se-DETA-H and Cd 0.5 Zn 0.5 Se-DETA-T were respectively dispersed in 50 mL of 0.25 M Na 2 S and 0.35 M Na 2 SO 3 solution to form a uniform suspension. Then, the above suspension was transferred to a quartz reactor and connected to an on-line evaluation system (CEL-SPH2N, CEAu Light) with a closed gas circulation. The air in the reactor and the system was removed by vacuum, and photocatalytic hydrogen production tests were carried out using a 300 W xenon lamp (Beijing Perfect Light PLS-SXE 300) with a 420 nm cut-off filter. Samples were taken once every 30 min, and the generated H 2 gas was detected using a gas chromatograph (Aulight GC-7920) equipped with a thermal conductivity detector (TCD). The test results are asFigure 5 as shown

[0082] According to Figure 5 It can be seen that the Cd 0.5 Zn 0.5 Se-DETA-H-P prepared by the light-assisted hydrothermal / solvothermal method of the present invention exhibits the best hydrogen production performance, and its hydrogen production rate is 1.84 times that of Cd 0.5 Zn 0.5 Se-DETA-T and 16.83 times that of Cd 0.5 Zn 0.5 Se-DETA-H, reaching 15.8 mmol·h -1 ·g -1 .

[0083] As can be seen from the above embodiments, the materials synthesized by the light-assisted hydrothermal / solvothermal method provided by the present invention show extremely excellent effects in hydrogen production performance, and this synthesis method has important application significance in the field of material synthesis and preparation.

[0084] Although the above embodiments have described the present invention in detail, they are only a part of the embodiments of the present invention, not all embodiments. Other embodiments can also be obtained according to these embodiments without creative efforts, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for efficiently preparing nanomaterials by light-assisted hydrothermal / solvothermal method, characterized in that: The following steps are involved: Metal salt, organic amine and semiconductor element are mixed under light conditions to carry out hydrothermal / solvothermal reaction to obtain organic-inorganic hybrid nanomaterials; the temperature of the hydrothermal / solvothermal reaction is 80-160° C., and the insulation reaction time is 0.5-3 hours.

2. The method according to claim 1, characterized in that The intensity of the light is 100-400 mW / cm 2 .

3. The method according to claim 1 or 2, characterized in that: The hydrothermal / solvothermal reaction is carried out in a protective atmosphere.

4. The method according to claim 3, characterized in that The hydrothermal / solvothermal reaction also includes exhausting air before the reaction.

5. The method according to claim 1, characterized in that The metal salt is an organic metal salt; the organic metal salt includes one or more of an organic cadmium salt and an organic zinc salt.

6. The method according to claim 1, characterized in that The organic amine is an unsaturated organic amine.

7. The method according to claim 1 or 6, characterized in that: The semiconductor element includes one or both of selenium and sulfur.

8. The method according to claim 1, 5 or 6, characterized in that: The mass ratio of the metal salt to the organic amine is 219-267:38400.

9. The method according to claim 1 or 5, characterized in that: The molar ratio of the metal salt to the semiconductor element is 99.9-100.1:99.9-100.

1.

10. The method according to claim 1, characterized in that The mixing is performed by alternating ultrasound and stirring; the power of the ultrasound is not higher than 100W; the time of a single ultrasound is 2 to 8 minutes; the speed of the stirring is 350 to 550 r / min; the time of a single stirring is 0.5 to 2 minutes; and the mixing time is 10 to 30 minutes.

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