Construction of chiral Au (at) CeO2 spiral nanorod and application of chiral Au (at) CeO2 spiral nanorod in field of photocatalysis

Abstract

The invention relates to a construction method of a chiral Au (at) CeO2 spiral nanorod with a spatial separation structure and photocatalysis application research of nitrogen fixation ammonia production efficiency under excitation of circularly polarized light, and belongs to the field of photocatalysis. The invention provides an Au (at) CeO2HNRs chiral nanomaterial with a spatial separation structure. A chiral catalyst system comprises a chiral plasma gold spiral nanorod and semiconductor CeO2 nanoparticles; and the semiconductor CeO2 nano-particles incompletely cover the surface of the chiral plasma gold spiral nano-rod. The preparation method comprises the following steps: firstly, constructing a gold nanorod (L / D-Au HNR) with a chiral helical structure by utilizing a seed mediation method, and then realizing selective growth of CeO2 on the surface of the L / D-Au HNR by utilizing a wet chemical method, so that a spatial separation structure is formed between Au and CeO2. The chiral structure catalytic material shows a circularly polarized light dependent photocatalytic effect, and the nitrogen fixation ammonia production efficiency is improved by 50.80 + / -2.64 times when the chiral structure catalytic material is used for nitrogen fixation ammonia production. The chiral plasma nano-catalyst constructed by the invention has a relatively high application value in the field of special photocatalysis.

Description

Technical Field

[0001] The present application belongs to the field of material science and technology, and specifically relates to the construction and photocatalytic application of chiral Au@CeO2 spiral nanorods. Background Art

[0002] Chiral plasmonic nanomaterials have become a research hotspot due to their size- and morphology-dependent physical, chemical, and optical properties. Among many research fields, chiral plasmonic nanomaterials have excellent abilities to absorb, scatter, and rotate polarized light in photocatalysis, which can promote plasma oscillations, thereby further significantly enhancing the generation of hot carriers, thereby improving the catalytic efficiency of many chemical reactions. Among them, electromagnetic excitation mediated by circularly polarized light (CPL) can lead to the asymmetric generation of hot carriers in chiral plasmonic nanomaterials. When the rotation direction of CPL is aligned with the chirality of the nanomaterial, the catalytic efficiency can be greatly improved by promoting the generation of hot carriers.

[0003] Precisely regulating the structure of photocatalytic materials is an effective way to improve the catalytic efficiency of plasmonic nanomaterials. However, research on improving the photocatalytic performance of chiral plasmonic nanomaterials through structural regulation is still in its infancy.

[0004] Combining plasmonic nanomaterials with metal oxides with excellent catalytic properties can improve the photocatalytic ability of plasmonic nanomaterials, which can not only help adjust the absorption range and photon responsiveness, but also enhance the photocatalytic performance of plasmonic nanomaterials and reduce energy consumption. However, the current methods of constructing chiral composite nanomaterials require high costs and complex technical requirements, making them difficult to be widely used.

[0005] Therefore, it is of great significance to explore simpler and more effective methods to construct chiral composite nanomaterials with excellent photocatalytic efficiency. Summary of the invention

[0006] Based on the above problems, the present invention mainly develops a L / D-Au@CeO2HNRs catalyst, and a preparation method and use thereof to overcome the existing technical problems.

[0007] The first aspect of the present application provides an Au@CeO2HNRs chiral nanomaterial with a spatial separation structure, wherein the chiral catalyst system comprises chiral plasma gold spiral nanorods and semiconductor CeO2 nanoparticles; the semiconductor CeO2 nanoparticles are covered on the surface of the chiral plasma gold spiral nanorods;

[0008] Furthermore, the semiconductor CeO2 nanoparticles do not completely cover the surface of the chiral plasma gold spiral nanorods.

[0009] The Au@CeO2 HNRs chiral nanomaterial with a spatial separation structure has circularly polarized light dependence.

[0010] Furthermore, the chiral gold helical rods are formed by gold nanorods induced by chiral amino acids; including L-AuHNRs or D-AuHNRs

[0011] The second aspect of the present application provides a method for preparing the Au@CeO2 HNRs chiral nanomaterial with a spatial separation structure, comprising the following steps:

[0012] S1: Synthesis of gold nanorod precursor solution;

[0013] S2: introducing chiral morphology and chiral signals into the gold nanorods prepared in step S1 to obtain a chiral plasma metal matrix;

[0014] S3: In step S2, cerium acetate solution and precursor solution are introduced into the system, and a redox reaction occurs on the surface of the chiral plasma gold helical nanorods to obtain cerium dioxide nanoparticles, thereby obtaining the L / D-Au@CeO2HNRs chiral nanomaterial with structural spatial separation.

[0015] Furthermore, in step S1, a chiral catalyst metal matrix is ​​constructed using gold nanorods with adjustable plasma absorption peaks;

[0016] Further, step S1 uses a seed-mediated method to synthesize a gold nanorod precursor solution: a surfactant, sodium oleate, silver nitrate, ascorbic acid and a gold seed solution are added to form a first mixed reaction system for a first reaction, and a gold nanorod solution with an adjustable plasma absorption peak is obtained by adjusting the amount of hydrochloric acid added;

[0017] Furthermore, step S1 includes steps S11, S12 and S13;

[0018] S11. Preparation of seed solution: NaBH4 solution was added to a mixed solution comprising chloroauric acid and CTAB, stirred vigorously, and the resulting seed solution was placed at room temperature for use;

[0019] S12. Preparation of a growth solution: Dissolve CTAB and sodium oleate in water, add silver nitrate after cooling, add chloroauric acid solution after a period of reaction; stir the reaction, add hydrochloric acid, stir the reaction, and then add ascorbic acid;

[0020] S13. Mix the seed solution prepared in step S11 with the growth solution prepared in step S12, let them stand for growth, and collect them by centrifugation to obtain gold nanorods.

[0021] In some embodiments, in step S12, the concentration of added hydrochloric acid is 11-12M, and the volume ratio of hydrochloric acid to the reaction system is (35-72):10000.

[0022] In some embodiments of the present invention, in step S1, the temperature of the first reaction system is 30-35° C., and the total time is 12-16 h.

[0023] Furthermore, in step S11, the stirring speed is 600-800 rpm and the time is 80-90 min; in step S12, the time is 10-15 min and the stirring speed is 350-450 rpm; in step S13, the time is 12-13 h, and the temperature of the three stages is 30-35°C.

[0024] Furthermore, in step S2, chiral amino acids, chloroauric acid solution, silver nitrate solution and ascorbic acid are added to the gold nanorod solution to form a second mixed reaction system for a second reaction to obtain a chiral gold helical nanorod solution containing a helical morphology and a chiral signal;

[0025] Furthermore, step S2 includes steps S21 and S22;

[0026] S21. The gold nanorods, CTAB, chiral amino acids and 4-ATP prepared in step S1 are added to water, and the mixed solution is incubated for a period of time;

[0027] S22. Add a solution of silver nitrate, chloroauric acid and ascorbic acid to the solution prepared in S21, heat for reaction and then collect by centrifugation to obtain chiral helical gold nanorods.

[0028] Furthermore, the time of step S21 is 3-3.5 hours, and the reaction temperature is 30-35°C; the time of step S21 is 1-1.5 hours, and the reaction temperature is 70-75°C.

[0029] Further, step S3: adding cerium ions and precursor ions to the chiral gold spiral nanorods obtained in step S2 to react to obtain cerium dioxide nanoparticles, and reacting at high temperature to form a third reaction system; obtaining a heterostructure containing a composite material with plasma and semiconductor, namely the L / D-Au@CeO2 HNRs chiral catalyst.

[0030] In some embodiments, in step S1, the surfactant is selected from at least one of CTAB and CTAC; preferably, cetyltrimethylammonium bromide (CTAB);

[0031] In some embodiments, step S3: the chiral gold helical nanorods obtained in step S2 are washed with water and dissolved in a CTAB solution; then a potassium chloroplatinite solution is added, and after stirring for reaction, a cerium acetate solution and ultrapure water are added to the prepared solution under continuous stirring, and a chiral Au@CeO2 HNRs chiral catalyst is obtained after heating for reaction.

[0032] In some embodiments, in step S1, the concentration of CTAB in the gold seed is 0.05-0.15 M, the concentration of HAuCl4 is 0.2-0.3 mM,

[0033] Furthermore, in step S2, the chiral amino acid is selected from at least one of cysteine ​​and chiral penicillamine; preferably cysteine, including L-Cys and D-Cys;

[0034] In some embodiments, in step S2, the second reaction system comprises a chiral cysteine ​​solution having a concentration of 0.4-0.6 mM and a volume of 0.05-0.15 mL, and a gold nanorod precursor solution having a volume of 2.5-3.5 mL;

[0035] In some embodiments of the present invention, in step S2, the temperature of the second reaction system is 30-70° C., and the reaction time is 4-5 h.

[0036] In some embodiments of the present invention, in step S3, the cerium ion includes at least one of cerium acetate and cerium nitrate; preferably cerium acetate, with a concentration of 0-0.5 mM; preferably, 0.1-0.3 mM.

[0037] In some embodiments of the present invention, the precursor ions include at least one of silver ions, platinum ions, and platinum-containing ions;

[0038] Furthermore, in step S3, the ratio of cerium ions to chiral plasma gold helical nanorods is 1 ml: (1.75-2) mg; wherein the concentration of cerium ions is 0-0.5 mM.

[0039] In some embodiments, the third reaction system comprises a cerium acetate solution with a concentration of 0-0.5 mM and a volume of 0.1 mL, and a gold helical nanorod precursor solution with a concentration of 0.035-0.04 mg / mL and a volume of 5 mL.

[0040] Furthermore, in step S3, the reaction time of the third reaction system is 1-1.5 h, and the reaction temperature is 100-110°C.

[0041] In a more specific implementation case of the present application, a method for constructing a L / D-Au@CeO2HNRs chiral catalytic system with a spatial separation structure includes: using a seed-mediated method, CTAB, chloroauric acid, silver nitrate, ascorbic acid and hydrochloric acid react under certain temperature conditions for a period of time to form a gold nanorod precursor solution; then adding chiral cysteine ​​thereto, and then chloroauric acid and silver nitrate form chiral gold spiral nanorods with a spiral morphology under ascorbic acid reduction; finally, introducing a cerium acetate solution, a redox reaction occurs to form cerium dioxide nanoparticles on the surface of the gold spiral nanorods, and L / D-Au@CeO2 HNRs chiral catalyst materials with different morphologies are obtained.

[0042] Exemplarily, the preparation method may specifically include: first, reducing chloroauric acid with sodium borohydride to obtain a gold seed solution for standby use, preparing a growth solution containing a surfactant, sodium oleate, silver nitrate, and chloroauric acid, then placing the growth solution in hydrochloric acid and stirring it evenly, adding ascorbic acid and a gold seed solution thereto after stirring for a period of time, and obtaining a gold nanorod precursor solution after the reaction is complete; then, adding the gold nanorod precursor solution to an aqueous solution containing a chiral ligand, and adding 4-aminothiophenol, standing the solution for a period of time at a certain temperature, then adding chloroauric acid, a silver nitrate solution, and ascorbic acid, and then continuing the reaction for a certain period of time to allow the gold and silver ions to be fully reduced and grown, thereby obtaining chiral gold helical nanorods with chiral optical signals; then, adding chloroplatinic acid ions and cerium ions to the chiral gold helical nanorod solution, so that a redox reaction occurs to obtain cerium dioxide nanoparticles, and then obtaining L / D-Au@CeO2 HNRs chiral catalyst materials with spatial structural separation; and further performing ammonia fixation catalysis under polarized light.

[0043] Wherein, the surfactant is CTAB, the chiral ligand is chiral cysteine: L-Cys and D-Cys, the precursor is chloroplatinite ion, specifically potassium chloroplatinite solution, and the cerium ion is cerium acetate solution.

[0044] Furthermore, the preparation method may specifically include: preparing a gold seed solution with sodium borohydride in advance and placing it at room temperature for 1-1.5 hours for standby use, then preparing a mixed growth solution of 13-15 mg / mL CTAB, 2.3-2.5 mg / mL sodium oleate, 0.1-0.2 mM silver nitrate, and 0.4-0.6 mM chloroauric acid, adding 11-12 M hydrochloric acid, 0.1-0.2 mM ascorbic acid and seeds, and reacting and growing at 30-35° C. for 10-14 hours to obtain a gold nanorod solution; then adding 0.5-0.7 mM L-Cys or D-Cys; 0.3-0.6 mM 4-Aminobenzenethiol and gold nanorod solution are reacted at 30-35°C for 3-3.5h, and then 0.4-0.6mM silver nitrate, 1-3mM chloroauric acid and 9-11mM ascorbic acid are added, and the reaction is carried out at 30-70°C for 1-1.5h to obtain chiral gold spiral nanorods; then 0.05-0.15mM potassium chloroplatinite and 0.15-0.25mM cerium acetate are added to the gold spiral nanorods after centrifugation, and the reaction is carried out at 100-110°C for 1-1.5h to obtain the L / D-Au@CeO2 HNRs chiral catalytic system.

[0045] The third aspect of the present application provides the application of the Au@CeO2 HNRs chiral nanomaterial with a spatial separation structure, which can be applied to the fields of chemical catalysis and photocatalysis.

[0046] In some embodiments, the present invention provides the Au@CeO2 HNRs chiral nanomaterial for nitrogen fixation catalysis to produce ammonia; the catalytic system is a photocatalytic system;

[0047] Furthermore, the L / D-Au@CeO2 HNRs chiral catalyst material catalyzes nitrogen to produce ammonia under circularly polarized light irradiation;

[0048] Furthermore, the polarized light includes linear polarized light, left circular polarized light and right circular polarized light; wherein the illumination power of the polarized light is 11-13 W·cm -2 In a preferred embodiment, the illumination power is 12.7 W·cm -2 ;

[0049] Furthermore, the nitrogen rate during the catalytic nitrogen fixation reaction is 8-10 mL min -1 ; preferably 10mL·min -1 .

[0050] Furthermore, the catalytic activity of the L / D-Au@CeO2 HNRs chiral catalytic system was evaluated by calibrating the content of ammonia produced during the catalytic process.

[0051] In some embodiments, the photocurrent and photoresistance signals are measured from an electrochemical workstation to compare the transmission efficiency of the L / D-Au@CeO2HNRs chiral catalytic material;

[0052] In a preferred embodiment, the concentration of chiral L / D-Au@CeO2HNRs catalyst is 0.055 mg / mL;

[0053] The L / D-Au@CeO2 HNRs chiral catalyst system can effectively transport hot electrons and can provide new methods and strategies for chiral materials in the field of chemical photocatalysis.

[0054] Beneficial effects: Compared with the prior art, the beneficial effects of the technical solution of this application are at least:

[0055] (1) The present invention provides a chiral catalytic material L / D-Au@CeO2 HNRs with a spatial separation structure, and also provides a method for preparing the chiral plasma nanocatalyst. The preparation method is simple, has good catalytic effect, and is suitable for large-scale production.

[0056] (2) The provided L / D-Au@CeO2 HNRs chiral catalytic system has strong controllability and can be used as a new chiral catalytic material to provide guidance for the construction of new chiral catalyst materials;

[0057] (3) The provided L / D-Au@CeO2 HNRs chiral catalytic system extends chiral catalysis to the field of energy catalysis, has strong photochemical catalytic activity, and has good polarization dependence on light. Compared with normal illumination, it has better catalytic effect when the helicity of photons and materials matches;

[0058] (4) The modified material was used for nitrogen fixation and ammonia production catalysis. The efficiency of nitrogen fixation and ammonia production was increased by 50.80±2.64 times compared with L / D-Au HNR without a separation structure. It has high application value in the field of chiral catalyst regulation and chemical catalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0060] Figure 1 are transmission electron microscopy images of L / D-Au@CeO2 HNRs chiral catalysts in different implementations;

[0061] Figure 2 is a high-resolution transmission electron microscopy photograph of the L-Au@CeO2 HNRs chiral catalyst in Example 1;

[0062] Figure 3 is the EDX-Mapping image of the L / D-Au@CeO2 HNRs chiral catalyst in Example 1;

[0063] Figure 4 is the X-ray diffraction spectrum of the L-Au@CeO2 HNRs chiral catalyst in Example 1;

[0064] Figure 5 is the X-ray electron spectrum of the L-Au@CeO2 HNRs chiral catalyst in Example 1;

[0065] Figure 6 are the circular dichroism spectra of L / D-Au@CeO2 HNRs chiral catalysts in different implementation modes;

[0066] Figure 7 is the UV absorption spectra of L / D-Au@CeO2 HNRs chiral catalyst in different implementation modes;

[0067] Figure 8 It is the photocurrent response ability test of L-Au@CeO2 HNRs chiral catalyst in different implementation modes;

[0068] Fig. 9 is a bar graph of nitrogen catalytic efficiency of L-Au@CeO2 HNRs chiral catalyst under linear polarized light in different implementation modes;

[0069] Fig.10 is a bar graph of nitrogen catalytic efficiency of the L-Au@CeO2 HNRs chiral catalyst under different circularly polarized lights in Example 1;

[0070] Fig.11 Schematic diagram of the principle of preparing the chiral photocatalyst of the present invention;

[0071] Fig.12 Schematic diagram of the principle of producing ammonia from nitrogen catalyzed by the chiral photocatalyst of the present invention. DETAILED DESCRIPTION

[0072] The following describes the implementation of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application.

[0073] Example 1 Preparation of L / D-Au@CeO2 HNRs chiral catalyst:

[0074] S1. Prepare seed solution: Add freshly prepared ice-cold NaBH4 solution (0.02M, 1.2mL) to a mixed solution containing chloroauric acid (0.5mM, 5mL) and CTAB (0.2M, 5mL), and stir vigorously at 1200rpm. The resulting seed solution is placed at room temperature for 1h for standby use. Prepare growth solution: Dissolve 1.4g CTAB and 246.8mg sodium oleate in 50mL warm water. After cooling to 30℃, add silver nitrate (4mM, 3.6mL). After 15min, add chloroauric acid (1mM, 50mL) solution. After stirring for 90 minutes (700rpm), add 0.6mL 12M hydrochloric acid and stir at 400rpm for another 15min. After stirring vigorously for 30s, add ascorbic acid (0.064M, 0.25mL) to the mixed solution. The prepared seed solution (0.08 mL) was injected into the growth solution and left undisturbed at 30°C for 12 hours to grow, and the gold nanorods were collected by centrifugation at 8000 rpm for 10 min.

[0075] S2. Add 3 mL of gold rod, 0.5 mL of 200 mM CTAB, 0.1 mL of 6 mM L-Cys or D-Cys, and 0.1 mL of 4 mM 4-ATP to 6.3 ml of water, and incubate the mixed solution at 30°C for 3 h.

[0076] A solution of silver nitrate (5 mM, 0.14 mL), chloroauric acid (20 mM, 0.65 mL) and ascorbic acid (100 mM, 0.56 mL) was added to the prepared solution, the resulting solution was kept at 70°C for 1 h, and the chiral helical gold nanorods were collected by centrifugation at 7000 rpm for 5 min.

[0077] S3, 5mL chiral gold helical nanorods were pre-treated by water washing and dissolved in 2.5ml 0.1mM CTAB solution. Then, 0.2mL 0.1mM potassium chloroplatinate solution was added, while stirring at 300rpm and kept at room temperature for 4 minutes. After that, 0.1mL 10mM cerium acetate solution and 4.7mL ultrapure water were added to the prepared solution under continuous stirring at 300rpm. The solution was placed at 100℃ for 1h to obtain the chiral Au@CeO2 HNRs chiral catalyst (named Little).

[0078] Example 2 Preparation of L / D-Au@CeO2 HNRs chiral catalyst:

[0079] S1. Prepare seed solution: Add freshly prepared ice-cold NaBH4 solution (0.02M, 1.2mL) to a mixed solution containing chloroauric acid (0.5mM, 5mL) and CTAB (0.2M, 5mL), and stir vigorously at 1200rpm. The resulting seed solution is placed at room temperature for 1h for standby use. Prepare growth solution: Dissolve 1.4g CTAB and 246.8mg sodium oleate in 50mL warm water. After cooling to 30℃, add silver nitrate (4mM, 3.6mL). After 15min, add chloroauric acid (1mM, 50mL) solution. After stirring for 90 minutes (700rpm), add 0.6mL 12M hydrochloric acid and stir at 400rpm for another 15min. After stirring vigorously for 30s, add ascorbic acid (0.064M, 0.25mL) to the mixed solution. Finally, the prepared seed solution (0.08 mL) was injected into the growth solution and left undisturbed at 30 °C for 12 h to grow, and the gold nanorods were collected by centrifugation at 8000 rpm for 10 min.

[0080] S2, 3mL gold rods, 0.5mL 200mM CTAB, 0.1mL 6mM L-Cys or D-Cys and 0.1mL4 mM4-ATP were added to 6.3ml water, and the mixed solution was incubated at 30°C for 3h. Then, a solution of silver nitrate (5mM, 0.14mL), chloroauric acid (20mM, 0.65mL) and ascorbic acid (100mM, 0.56mL) was added to the prepared solution, the resulting solution was kept at 70°C for 1h, and the chiral helical gold nanorods were collected by centrifugation at 7000rpm for 5min.

[0081] S3, 5mL chiral gold helical nanorods were pre-treated by water washing and dissolved in 2.5ml 0.1mM CTAB solution. Then, 0.2mL 0.1mM potassium chloroplatinite solution was added, while stirring at 300rpm and kept at room temperature for 4 minutes. After that, 4.7mL ultrapure water was added to the prepared solution under continuous stirring at 300rpm. The solution was placed at 100℃ for 1h to obtain the chiral Au@CeO2 HNRs chiral catalyst (named None).

[0082] Example 3 Preparation of L / D-Au@CeO2 HNRs chiral catalyst:

[0083] S1. Prepare seed solution: Add freshly prepared ice-cold NaBH4 solution (0.02M, 1.2mL) to a mixed solution containing chloroauric acid (0.5mM, 5mL) and CTAB (0.2M, 5mL), and stir vigorously at 1200rpm. The resulting seed solution is placed at room temperature for 1h for standby use. Prepare growth solution: Dissolve 1.4g CTAB and 246.8mg sodium oleate in 50mL warm water. After cooling to 30℃, add silver nitrate (4mM, 3.6mL). After 15min, add chloroauric acid (1mM, 50mL) solution. After stirring for 90 minutes (700rpm), add 0.6mL 12M hydrochloric acid and stir at 400rpm for another 15min. After stirring vigorously for 30s, add ascorbic acid (0.064M, 0.25mL) to the mixed solution. The prepared seed solution (0.08 mL) was injected into the growth solution and left undisturbed at 30°C for 12 hours to grow, and the gold nanorods were collected by centrifugation at 8000 rpm for 10 min.

[0084] S2, 3mL gold rods, 0.5mL 200mM CTAB, 0.1mL 6mM L-Cys or D-Cys and 0.1mL4 mM4-ATP were added to 6.3ml water, and the mixed solution was incubated at 30°C for 3h. Then, a solution of silver nitrate (5mM, 0.14mL), chloroauric acid (20mM, 0.65mL) and ascorbic acid (100mM, 0.56mL) was added to the prepared solution, the resulting solution was kept at 70°C for 1h, and the chiral helical gold nanorods were collected by centrifugation at 7000rpm for 5min.

[0085] S3, 5mL chiral gold helical nanorods were pre-treated by water washing and dissolved in 2.5ml 0.1mM CTAB solution. Then, 0.2mL 0.1mM potassium chloroplatinite solution was added, while stirring at 300rpm and kept at room temperature for 4 minutes. After that, 0.3mL 10mM cerium acetate solution and 4.4mL ultrapure water were added to the prepared solution under continuous stirring at 300rpm. The solution was placed at 100℃ for 1h to obtain the chiral Au@CeO2 HNRs chiral catalyst (named Most).

[0086] Example 4 Preparation of L / D-Au@CeO2 HNRs chiral catalyst:

[0087] S1. Prepare seed solution: Add freshly prepared ice-cold NaBH4 solution (0.02M, 1.2mL) to a mixed solution containing chloroauric acid (0.5mM, 5mL) and CTAB (0.2M, 5mL), and stir vigorously at 1200rpm. The resulting seed solution is placed at room temperature for 1h for standby use. Prepare growth solution: Dissolve 1.4g CTAB and 246.8mg sodium oleate in 50mL warm water. After cooling to 30℃, add silver nitrate (4mM, 3.6mL). After 15min, add chloroauric acid (1mM, 50mL) solution. After stirring for 90 minutes (700rpm), add 0.6mL 12M hydrochloric acid and stir at 400rpm for another 15min. After stirring vigorously for 30s, add ascorbic acid (0.064M, 0.25mL) to the mixed solution. The prepared seed solution (0.08 mL) was injected into the growth solution and left undisturbed at 30°C for 12 hours to grow, and the gold nanorods were collected by centrifugation at 8000 rpm for 10 min.

[0088] S2, 3mL gold rods, 0.5mL 200mM CTAB, 0.1mL 6mM L-Cys or D-Cys and 0.1mL4 mM4-ATP were added to 6.3ml water, and the mixed solution was incubated at 30°C for 3h. Then, a solution of silver nitrate (5mM, 0.14mL), chloroauric acid (20mM, 0.65mL) and ascorbic acid (100mM, 0.56mL) was added to the prepared solution, the resulting solution was kept at 70°C for 1h, and the chiral helical gold nanorods were collected by centrifugation at 7000rpm for 5min.

[0089] S3, 5mL chiral gold helical nanorods were pre-treated by water washing and dissolved in 2.5ml 0.1mM CTAB solution. Then, 0.2mL 0.1mM potassium chloroplatinate solution was added, while stirring at 300rpm and kept at room temperature for 4 minutes. After that, 0.5mL 10mM cerium acetate solution and 4.2mL ultrapure water were added to the prepared solution under continuous stirring at 300rpm. The solution was placed at 100℃ for 1h to obtain the chiral Au@CeO2 HNRs chiral catalyst (named Full).

[0090] Example 5 Nitrogen fixation catalysis:

[0091] To further analyze the catalytic effect of the chiral catalyst, the heterostructure catalyst with the highest charge separation efficiency (prepared in Example 1) was selected to carry out nitrogen fixation catalysis under polarized light.

[0092] The L / D-Au@CeO2 HNRs chiral catalyst is used for photocatalytic nitrogen fixation to produce ammonia, which includes the following steps:

[0093] S1. Nitrogen fixation was carried out in a photocatalytic reactor. In the catalytic reaction, 5.5 mg L / D-Au@CeO2 HNRs were dispersed in 100 mL of water, and methanol was selected as a hole scavenger. 2 mL of the photocatalyst solution was mixed with 0.5 mL of methanol solution (4:1, v / v, 2.5 mL), and then the mixture was ultrasonicated for 5 min.

[0094] S2, then at a pressure of 1 atm with constant high-purity N2 (50 mL min -1 The prepared solution was irradiated with linear polarized light (LPL) and left and right circularly polarized light (LCPL and DCPL, 808 nm) at a light power density of 12.7 W cm -2 , the spot diameter was 5 mm. During the entire photocatalytic process, N2 (10 mL min -1 After 2 hours of illumination, the catalyst was removed by centrifugation, and indophenol blue reagent was added dropwise to measure the ammonia catalytic product in the supernatant by ultraviolet light to obtain the ammonia production efficiency.

[0095] Test Example: The morphology, chemical and optical properties of the L / D-Au@CeO2 HNRs chiral catalysts prepared in each example were confirmed and characterized by transmission electron microscopy, EDX-Mapping, X-ray diffraction spectroscopy, circular dichroism spectrometer, UV spectrophotometer and other instruments.

[0096] The product solution of the washed catalytic material obtained in Example 1 was dripped onto a copper mesh. After 30 minutes, the solution on the copper mesh was removed. After the copper mesh was completely dried, the morphology was observed using a transmission electron microscope. The transmission electron microscope photos of the photocatalyst synthesized by L-Cys and D-Cys are shown in FIG. Figure 1 As shown in the high-resolution transmission electron microscopy images Figure 2 As shown. From the transmission microscope photos, it can be seen that the nanoparticles are evenly distributed in the field of view, and the obvious spiral morphology on the surface of the gold rod can be clearly observed; when the magnification is increased, the lattice fringes of the connection between the plasma gold rod and the ceria can be observed through the high-resolution transmission electron microscope photos.

[0097] The element distribution of L-Au@CeO2 HNRs prepared in Example 1 was confirmed, and the individual nanoparticles were further characterized by mapping ( Figure 3 ), the element distribution of gold, silver, oxygen, and cerium can be seen from the obtained element distribution map, indicating the successful construction of the heterostructure. In order to further confirm the L-Au@CeO2 HNRs, an X-ray crystal diffractometer (such as Figure 4 ) and X-ray electron spectrometers (such as Figure 5) confirmed the composition of the material. From the obtained XRD spectrum, it can be seen that the XRD of the product can correspond to the standard PDF cards of gold #89-3697 and cerium dioxide #81-0792, respectively, proving that the product is composed of gold and cerium dioxide. At the same time, it can be seen from XPS that most of the Ce element in the structure is tetravalent, further verifying the formation of cerium dioxide.

[0098] The L / D-Au@CeO2 HNRs prepared in Example 1 were respectively measured by a circular dichroism spectrometer (such as Figure 6 ) and UV spectrophotometer absorption spectrometer (such as Figure 7 ) was tested, and it can be seen from the circular dichroism spectrum that there is a strong mirror-symmetric chiral signal around 500-900nm, and the distribution range of the chiral signal is completely consistent with the absorption signal, which fully proves the controllable synthesis of the L / D-Au@CeO2 HNRs catalytic system.

[0099] In order to detect the photocatalytic ability of L / D-Au@CeO2 HNRs chiral photocatalysts, the photocurrent influence ability of L-Au@CeO2 HNRs chiral catalysts with different structural morphologies was further compared (e.g. Figure 8 The specific process is as follows: First, the synthesized L-Au@CeO2 HNRs chiral catalysts with different structural morphologies are applied to the front of the conductive glass, and then tested with an electrochemical workstation after drying. From the test results, it can be seen that the spatially separated heterostructure catalyst with coexistence of bare gold surface and cerium dioxide has the strongest photocurrent response ability (L-Little, L-Most). From the perspective of the photocatalytic nitrogen fixation efficiency of different morphologies (such as Fig. 9 ), when LPL was used to irradiate L-None, L-Little, L-Most, and L-Full catalytic materials, their nitrogen fixation efficiencies were 2.295, 116.612, 72.156, and 23.163 μmol h, respectively. -1 g -1 , which fully proves that Au@CeO2HNRs nanoparticles have good photocatalytic performance, especially when Au and CeO2 have a spatially separated structure.

[0100] To further analyze the catalytic effect of chiral catalysts, the heterogeneous catalyst with the highest charge separation efficiency (Little) was selected to carry out nitrogen fixation catalysis under polarized light (e.g. Fig.10 ), when LCPL was selected to irradiate L-Little and D-Little, the nitrogen fixation efficiencies of the materials were 190.102 and 70.34 μmol h -1 g -1When RCPL was selected for L-Little and D-Little, the nitrogen fixation efficiencies of the materials were 189.194 and 69.433 μmol h -1 g -1 In addition, when LPL was selected for irradiation, the nitrogen fixation efficiencies of L-Little and D-Little were 120.24 and 112.98 μmol h, respectively. -1 g -1 The catalytic results show that when the helicity of the photon and the material match, the catalytic efficiency is greatly improved, which further proves that the chiral catalyst of L / D-Au@CeO2 HNRs has good photocatalytic performance. The nitrogen fixation and ammonia production performance of L / D-Au@CeO2 HNR shows a circularly polarized light-dependent photocatalytic effect. When the chiral configuration of L / D-Au@CeO2 HNR matches the polarization direction of circularly polarized light, its catalytic efficiency is significantly higher than that obtained using circularly polarized light with the opposite polarization direction.

[0101] In summary, the present invention firstly constructs gold nanorods (L / D-AuHNR) with a chiral helical structure by a seed-mediated method, and then realizes the selective growth of CeO2 on the surface of L / D-Au HNR by a wet chemical method, and can controllably adjust the construction process of L / D-Au@CeO2 HNR to make Au and CeO2 have a spatial separation structure. This chiral structure improves the nitrogen fixation and ammonia production efficiency of L / D-Au HNR by 50.80±2.64 times. The L / D-Au@CeO2HNRs chiral catalytic system prepared in this application has good controllability and good photocatalytic performance. The preparation method is controllable, efficient, and suitable for large-scale production. It has high application value in the field of chiral catalyst regulation and chemical catalysis.

[0102] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. An Au@CeO2 HNRs chiral nanomaterial with a spatial separation structure, characterized in that: The chiral catalyst system includes chiral plasmonic gold helical nanorods and semiconductor CeO2 nanoparticles; The semiconductor CeO2 nanoparticles do not completely cover the surface of the chiral plasma gold spiral nanorods.

2. The method for preparing the Au@CeO2 HNRs chiral nanomaterial with a spatial separation structure according to claim 1, characterized in that: The following steps are involved: S1: Synthesis of gold nanorod precursor solution; S2: introducing chiral morphology and chiral signals into the gold nanorods prepared in step S1 to obtain chiral plasma gold helical nanorods; S3: In step S2, cerium acetate solution and precursor solution are introduced into the system, and a redox reaction occurs on the surface of the chiral plasma gold helical nanorods to obtain cerium dioxide nanoparticles, thereby obtaining the L / D-Au@CeO2HNRs chiral nanomaterial with structural spatial separation.

3. The method for preparing chiral nanomaterials according to claim 2, characterized in that: In step S1, a seed-mediated method is used to synthesize a gold nanorod precursor solution: a surfactant, sodium oleate, silver nitrate, ascorbic acid and a gold seed solution are added to form a first mixed reaction system for a first reaction, and a gold nanorod solution with an adjustable plasma absorption peak is obtained by adjusting the amount of hydrochloric acid added; And / or, in step S2, chiral amino acid, chloroauric acid solution, silver nitrate solution and ascorbic acid are added to the gold nanorod solution to form a second mixed reaction system for a second reaction to obtain a chiral gold helical nanorod solution containing a helical morphology and a chiral signal; And / or, in step S3, cerium ions and precursor ions are added to the chiral gold spiral nanorods obtained in step S2 to react to obtain cerium dioxide nanoparticles, and a third reaction system is formed by high-temperature reaction; a heterostructure containing a composite material of plasma and semiconductor is obtained to obtain the L / D-Au@CeO2 HNRs chiral catalyst.

4. The method for preparing chiral nanomaterials according to claim 3, characterized in that: In step S1, the surfactant is selected from at least one of CTAB and CTAC; And / or, in step S1, the temperature of the first reaction system is 30-35°C and the time is 12-16h.

5. The method for preparing chiral nanomaterials according to claim 3, characterized in that: Step S1 includes S11. preparing a seed solution; S12. preparing a growth solution; S13. mixing the seed solution with the growth solution to prepare a gold nanorod precursor solution; In step S12, the concentration of added hydrochloric acid is 11-12M, and the volume ratio of hydrochloric acid to the reaction system is (35-72):10000.

6. The method for preparing chiral nanomaterials according to claim 3, characterized in that: In step S2, the chiral amino acid is selected from at least one of cysteine ​​and chiral penicillamine; And / or, in step S2, the temperature of the second reaction system is 30-70°C, and the reaction time is 4-5h.

7. The method for preparing chiral nanomaterials according to claim 3, characterized in that: In step S3, The cerium ion includes at least one of cerium acetate and cerium nitrate; The precursor ions include at least one of silver ions, platinum ions, and platinum-containing ions; And / or, in step S3, the temperature of the third reaction system is 90-100° C., and the time is 1-1.2 h.

8. The method for preparing chiral nanomaterials according to claim 3, characterized in that: In step S3, the ratio of cerium ions to chiral plasmon gold helical nanorods is 1 ml: (1.75-2) mg; wherein the concentration of cerium ions is 0.1-0.3 mM.

9. The use of the L / D-Au@CeO2HNRs chiral catalytic material according to claim 1, characterized in that: It is used in the fields of circularly polarized light-mediated chemical catalysis and photocatalysis.

10. The use of the L / D-Au@CeO2HNRs chiral catalytic material according to claim 9, characterized in that: Applied to circularly polarized light-mediated nitrogen fixation catalysis to produce ammonia.

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