Chiral plasmonic photocatalyst and hydrogen production method using same

Abstract

The present application relates to a chiral plasmonic photocatalyst, a manufacturing method therefor, and a hydrogen production method using the chiral plasmonic photocatalyst. The photocatalyst according to embodiments of the present application can induce a high hydrogen production reaction by emitting a circularly polarized laser, capable of strongly interacting with chiral plasmonic metal nanoparticles, to induce the generation of a chiral near field and aligned thermal electrons, which correspond to effects corresponding to chiral plasmonic characteristics.

Description

Chiral plasmonic photocatalyst and hydrogen production method using the same

[0001] The present invention relates to a chiral plasmonic photocatalyst, a method for producing the same, and a method for producing hydrogen using the chiral plasmonic photocatalyst.

[0002] Hydrogen production via photocatalysis is an innovative and environmentally friendly approach that uses sunlight to produce hydrogen gas. Typically composed of semiconductor materials, photocatalysts absorb photons (light energy) to form electron-hole pairs. These electrons and holes then participate in a redox reaction to produce hydrogen and oxygen from water molecules. Photocatalysts contain cocatalysts that facilitate the separation and accumulation of electrons and holes. Using high-performance cocatalysts is crucial for enhancing photocatalytic performance. Cocatalysts can be precious metals such as platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir), and gold (Au), or transition metal oxides such as ruthenium oxide, rhodium oxide, nickel oxide, cobalt oxide, and chromium oxide.

[0003] Meanwhile, carbon-based eco-friendly photocatalysts such as graphitic carbon nitride and graphene are being studied, but the efficiency of the hydrogen production reaction is still limited due to the difficulty in controlling properties and low visible light absorption.

[0004] [Prior Art Literature]

[0005] [Patent Document]

[0006] Republic of Korea Patent Publication No. 10-2515798

[0007] The present invention provides a chiral plasmonic photocatalyst, a method for producing the same, and a method for producing hydrogen using the chiral plasmonic photocatalyst.

[0008] However, the problems that the present invention seeks to solve are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0009] The first aspect of the present invention provides a photocatalyst comprising: a substrate including a semiconductor; and chiral plasmonic metal nanoparticles formed on the substrate.

[0010] A second aspect of the present invention provides a method for producing a photocatalyst, comprising: obtaining a mixture comprising a substrate including a semiconductor and a metal precursor; and irradiating the mixture with circularly polarized light to grow chiral plasmonic metal nanoparticles on the substrate.

[0011] The third aspect of the present invention provides a method for producing hydrogen, comprising contacting a photocatalyst with water and irradiating the photocatalyst with circularly polarized light to obtain hydrogen, wherein the photocatalyst comprises a substrate comprising a semiconductor; and chiral plasmonic metal nanoparticles formed on the substrate.

[0012] The method for manufacturing a photocatalyst according to the embodiments of the present invention is to transfer chirality to metal particles through circularly polarized light to grow chiral plasmonic metal nanoparticles, and can be performed in a simple manner without introducing a chiral ligand.

[0013] The photocatalyst according to the embodiments of the present invention can induce a high hydrogen production reaction by irradiating a circularly polarized laser that can strongly interact with chiral plasmonic metal nanoparticles to induce chiral near-field and aligned hot electron generation, which are effects corresponding to chiral plasmonic properties.

[0014] Figure 1 is a schematic diagram showing a synthesis process of a chiral plasmonic photocatalyst in one embodiment of the present invention.

[0015] FIG. 2 shows the results of characterization of chiral plasmonic photocatalysts in one embodiment of the present invention, including TEM images of L-Au / C3N4 (a), R-Au / C3N4 (b), and 0-Au / C3N4 (c); EDS mapping analysis of R-Au / C3N4 (d); CD spectra (e), absorption spectra (f), BET analysis (g), and Tauc plots (h) of C3N4, L-Au / C3N4, R-Au / C3N4, and 0-Au / C3N4; and Au 4f XPS spectrum (i) of R-Au / C3N4.

[0016] FIG. 3 is a schematic diagram of hydrogen production reactions of L-Au / C3N4 and R-Au / C3N4 under RCP irradiation in one embodiment of the present invention (a); and a schematic diagram of CPL-enhanced generation of spin-oriented hot electrons of L-Au / C3N4 and R-Au / C3N4 under RCP irradiation (b).

[0017] Figure 4 shows, in one embodiment of the present invention, L-Au / C3N4 (a), R-Au / C3N4 (b), and (c) 0-Au / C3N 4- (d) shows the H2 production over time under LCP, RCP, and LP irradiation; and (e) shows the hydrogen production per hour compared.

[0018] FIG. 5 is a schematic diagram of an in-situ FT-IR aspect in one embodiment of the present invention (a), a change in transmittance obtained from real-time FT-IR spectra of each sample with different light irradiation conditions (b), a schematic diagram of the interaction of C3N4 and H2O molecules (c), FT-IR spectral changes according to irradiation time of LCP, LP, and RCP irradiated R-Au / C3N4 (d), and FT-IR spectral changes according to irradiation time of LCP, LP, and RCP irradiated L-Au / C3N4 (e).

[0019] FIG. 6 shows, in one embodiment of the present invention, the steady-state PL spectrum (a) of the photocatalyst and the time-resolved PL dynamics (b) of the photocatalyst at the corresponding steady-state emission peak, and a schematic diagram (c) of the charge transfer process of R-Au / C3N4 under LCP and RCP irradiation.

[0020] Hereinafter, with reference to the attached drawings, implementation examples and embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. However, the present invention may be implemented in various different forms and is not limited to the implementation examples and embodiments described herein. In addition, in the drawings, parts irrelevant to the description have been omitted to clearly explain the present invention, and similar parts have been designated with similar drawing reference numerals throughout the specification.

[0021] Throughout this specification, when a part is said to be "connected" to another part, this includes not only cases where it is "directly connected" but also cases where it is "electrically connected" with another element in between.

[0022] Throughout this specification, when it is said that an element is "on" another element, this includes not only cases where the element is in contact with the other element, but also cases where another element exists between the two elements.

[0023] Throughout this specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0024] The terms "about," "substantially," and the like used in this specification are used in a meaning that is at or close to the numerical value when manufacturing and material tolerances inherent in the meanings mentioned are presented, and are used to prevent unscrupulous infringers from unfairly exploiting the disclosure in which exact or absolute values ​​are mentioned to aid understanding of the present application.

[0025] The terms “step of ~” or “step of ~” as used throughout this specification do not mean “step for ~.”

[0026] Throughout this specification, the term "combination(s) thereof" included in the expressions in the Makushi format means one or more mixtures or combinations selected from the group consisting of the components described in the expressions in the Makushi format, and means including one or more selected from the group consisting of said components.

[0027] Throughout this specification, references to “A and / or B” mean “A or B, or A and B.”

[0028] Below, the implementation examples of the present invention are described in detail, but the present invention may not be limited thereto.

[0029] The first aspect of the present invention provides a photocatalyst comprising: a substrate including a semiconductor; and chiral plasmonic metal nanoparticles formed on the substrate.

[0030] In one embodiment of the present invention, the semiconductor may include at least one selected from graphitic carbon nitride (g-C3N4), titanium dioxide (TiO2), and strontium titanate (SrTiO3), but may not be limited thereto.

[0031] In one embodiment of the present invention, the substrate may be a semiconductor material that absorbs light to generate electron-hole pairs.

[0032] In one embodiment of the present invention, the metal nanoparticles may include one or more selected from Au, Ag, Pt, Zn, Cu, Pd, Rh, Re, and Rb, but may not be limited thereto.

[0033] In one embodiment of the present invention, the diameter of the metal nanoparticle may be from about 10 nm to about 100 nm, but may not be limited thereto.

[0034] In one embodiment of the present invention, the diameter of the metal nanoparticle may be, but is not limited to, about 10 nm to about 100 nm, about 10 nm to about 70 nm, about 10 nm to about 50 nm, about 10 nm to about 40 nm, about 30 nm to about 100 nm, about 30 nm to about 70 nm, about 30 nm to about 50 nm, or about 30 nm to about 40 nm.

[0035] In one embodiment of the present invention, the metal nanoparticles may have left-handed or right-handed chirality.

[0036] In one embodiment of the present invention, the metal nanoparticles may have left-handed or right-handed chirality, thereby interacting more strongly with circularly polarized light than with natural light and / or linearly polarized light. Specifically, the metal nanoparticles having left-handed chirality may interact more strongly with left-handed circularly polarized light, and the metal nanoparticles having right-handed chirality may interact more strongly with right-handed circularly polarized light.

[0037] In one embodiment of the present invention, the metal particles can strongly interact with circularly polarized light and promote the generation of excited electrons and holes, thereby exhibiting an enhanced catalytic activity effect.

[0038] In one embodiment of the present invention, the content ratio of the metal particles in the photocatalyst may be about 0.01 wt% to about 0.1 wt%, but may not be limited thereto.

[0039] In one embodiment of the present invention, the content ratio of the metal particles in the photocatalyst may be about 0.01 wt% to about 0.1 wt%, about 0.01 wt% to about 0.05 wt%, about 0.01 wt% to about 0.04 wt%, about 0.03 wt% to about 0.1 wt%, about 0.03 wt% to about 0.05 wt%, or about 0.03 wt% to about 0.04 wt%, but may not be limited thereto.

[0040] In one embodiment of the present invention, the metal particles can generate hot electrons having high energy by generating localized surface plasmon resonance (LSPR).

[0041] In one embodiment of the present invention, the metal particles have chirality, so that when irradiated with circularly polarized light, they may have a higher surface area, better thermal electron generation, and superior catalytic activity compared to a photocatalyst including conventional plasmonic metal particles.

[0042] In one embodiment of the present invention, the photocatalyst may be used in a water decomposition reaction.

[0043] In one embodiment of the present invention, the photocatalyst may be a photocatalyst for producing hydrogen, but may not be limited thereto.

[0044] A second aspect of the present invention provides a method for producing a photocatalyst, comprising: obtaining a mixture comprising a substrate including a semiconductor and a metal precursor; and irradiating the mixture with circularly polarized light to grow chiral plasmonic metal nanoparticles on the substrate.

[0045] Detailed descriptions of parts that overlap with the first aspect of the present application have been omitted, but the contents described in the first aspect of the present application may be equally applied even if the description is omitted in the second aspect of the present application.

[0046] In one embodiment of the present invention, the method for manufacturing the photocatalyst may be performed in a simple manner without introducing a chiral ligand by transferring chirality to the metal particles through circularly polarized light to grow chiral plasmonic metal particles.

[0047] In one embodiment of the present invention, the substrate absorbs circularly polarized light and emits electrons, and the metal ions in the metal precursor are reduced by the emitted electrons, thereby generating the metal nanoparticles.

[0048] In one embodiment of the present invention, at the initial stage of growth of the metal particles, metal seed particles having no chirality are generated, and thereafter, the metal seed particles are grown stereoselectively by circularly polarized light, so that metal particles having chirality can be formed.

[0049] In one embodiment of the present invention, when irradiating left-handed circularly polarized light, metal nanoparticles having left-handed chirality can be grown, and when irradiating right-handed circularly polarized light, metal nanoparticles having right-handed chirality can be grown.

[0050] In one embodiment of the present invention, the semiconductor may include at least one selected from graphitic carbon nitride (g-C3N4), titanium dioxide (TiO2), and strontium titanate (SrTiO3), but may not be limited thereto.

[0051] In one embodiment of the present invention, the metal nanoparticles may include one or more selected from Au, Ag, Pt, Zn, Cu, Pd, Rh, Re, and Rb, but may not be limited thereto.

[0052] In one embodiment of the present invention, the metal precursor may include HAuCl4, but may not be limited thereto.

[0053] In one embodiment of the present invention, the mixture may further comprise a sacrificial reagent.

[0054] In one embodiment of the present invention, the sacrificial reagent may include, but may not be limited to, methanol.

[0055] In one embodiment of the present invention, when the mixture includes the sacrificial reagent, the reduction of the metal ion can occur more easily as the holes generated by the light absorption of the substrate are removed by reacting with the sacrificial reagent.

[0056] The third aspect of the present invention provides a method for producing hydrogen, comprising contacting a photocatalyst with water and irradiating the photocatalyst with circularly polarized light to obtain hydrogen, wherein the photocatalyst comprises a substrate comprising a semiconductor; and chiral plasmonic metal nanoparticles formed on the substrate.

[0057] Detailed explanations of parts that overlap with the first aspect of the present application have been omitted, but the contents described in the first aspect of the present application may be equally applied even if the explanation is omitted in the third aspect of the present application.

[0058] In one embodiment of the present invention, the metal nanoparticles may have left-handed or right-handed chirality.

[0059] In one embodiment of the present invention, the circular polarization may be left-handed circular polarization or right-handed circular polarization.

[0060] In one embodiment of the present invention, when the metal nanoparticle has left-handed chirality, hydrogen can be generated by irradiating left-handed circularly polarized light, and when the metal nanoparticle has right-handed chirality, hydrogen can be generated by irradiating right-handed circularly polarized light.

[0061] In one embodiment of the present invention, in the hydrogen production method, the circularly polarized light can induce a higher hydrogen production reaction by strongly interacting with the chiral plasmonic metal particles of the photocatalyst, thereby inducing chiral near-field and thermal electron generation.

[0062] In one embodiment of the present invention, the hydrogen production rate of the hydrogen production method is about 1.2 μmol g -1 h -1 or about 1.3 μmol g -1 h -1 It could be strange.

[0063] Hereinafter, the present invention will be described in more detail using examples. However, the following examples are provided only to help understand the present invention, and the contents of the present invention are not limited to the following examples.

[0064] Example 1: Synthesis of chiral plasmonic photocatalysts

[0065] Figure 1 shows a schematic diagram of the synthesis process of a chiral plasmonic photocatalyst.

[0066] 1) 100 mg of graphitic carbon nitride (g-C3N4) was dispersed in 20 mL of deionized water and 5 mL of methanol. 100 μL of gold ion precursor HAuCl4 (7.06 mg / mL) was added, and the mixture was stirred and exposed to circularly polarized light (65 mW / cm 2) was irradiated for 2 hours. After the 2-hour reaction, centrifugation (10,000 rpm, 10 min) was performed twice to remove the supernatant, and the remaining solvent was dried in an oven at 70°C to obtain a catalyst in powder form. When irradiated with CPL light, C3N4 absorbs light, releases electrons, and gold ions are reduced. As the gold ions are reduced, gold nanoparticles with chirality grow on the g-C3N4 surface according to the polarization direction of the irradiated circularly polarized light (CPL). When irradiated with left circularly polarized (LCP) light, gold nanoparticles with left-circularly polarized ((L)-Au) chirality grow, and when irradiated with right-circularly polarized (RCP) light, gold nanoparticles with right-circularly polarized ((R)-Au) chirality grow. As a result, chiral plasmonic photocatalysts of L-Au / C3N4 and R-Au / C3N4 were obtained.

[0067] 2) In the early stage of growth, small, seed-shaped gold nanoparticles (Au seeds) without chirality are created, and then circularly polarized light promotes the growth of the particles enantioselectively, causing the particles to acquire directionality.

[0068] 3) When methanol is additionally added as a sacrificial agent, the holes created are removed through reaction, thereby enabling the reduction reaction of gold ions to occur more easily.

[0069] For comparison, linear polarization (LP) was investigated for 0-Au / C3N 4- was manufactured.

[0070] Table 1 below shows the synthesized photocatalysts (L-Au / C3N4, R-Au / C3N4, and 0-Au / C3N 4- ) shows the results of ICP-MS analysis.

[0071] Au sample weight (mg) sample concentration [ppm] RSDR-Au / g-C3N4 30 2.97 8 0.19 8 2 5.4 L-Au / g-C3N4 30 9.55 9 0.20 0 12.60 -Au / g-C3N4 40 2.69 5 0.58 12.0

[0072] Figure 2 shows the results of characterization of the synthesized chiral plasmonic photocatalysts. TEM (transmission electron microscope) images of L-Au / C3N4 (a), R-Au / C3N4 (b), and 0-Au / C3N4 (c); EDS (energy dispersive spectrometry) mapping analysis of R-Au / C3N4 (d); C3N4, L-Au / C3N4, R-Au / C3N4, and 0-Au / C3N 4-The CD (circular dichroism) spectrum (e), absorption spectrum (f), BET (Brunauer-Emmett-Teller) analysis (g), Tauc plot (h) and Au 4f XPS (X-ray photoelectron spectroscopy) spectrum (i) of R-Au / C3N4 are shown. (a-c) TEM image and (d) EDS mapping analysis data confirm that gold nanoparticles were uniformly formed on g-C3N4 without aggregation. In addition, it can be confirmed that chiral gold particles with directionality depending on the polarization were formed under LCP and RCP light, whereas achiral gold particles were synthesized under LP light. This can also be confirmed through the symmetric spectrum in (e) circular dichroism (CD) spectrum. (f) The absorption of gold nanoparticles (R-, 0-, L-Au / C3N4), which was not observed in C3N4, was optically confirmed at 540 nm in the absorption spectrum. (g) BET analysis confirmed that the surface area of ​​the catalyst with gold nanoparticles introduced was greater than that of C3N4, and that R-, L-Au / C3N4, which had chirality introduced, had a larger surface area than 0-Au / C3N4. (h) The band gap energies of R-, 0-, L-Au / C3N4 were calculated using the Tauuck plot, and were all confirmed to be approximately 2.57 eV. (i) XPS analysis of the R-Au / C3N4 catalyst confirmed that gold nanoparticles were well introduced.

[0073] Example 2: Hydrogen production reaction using chiral plasmonic photocatalyst

[0074] Figure 3a is a schematic diagram of the circularly polarized light (CPL)-enhanced hydrogen evolution reaction (HER) using a chiral plasmonic photocatalyst (Au / C3N4). Figure 3a is a schematic diagram of the hydrogen evolution reaction of L-Au / C3N4 and R-Au / C3N4 under RCP irradiation, which has an enhanced interaction between R-Au / C3N4 and water molecules under RCP irradiation and efficiently transfers oriented hot electrons to water molecules. Figure 3b is a schematic diagram of the CPL-enhanced generation of spin-oriented hot electrons of L-Au / C3N4 and R-Au / C3N4 under RCP irradiation, which shows that under RCP irradiation, R-Au generates a large number of chiroptical reactive hot electron carriers that can be transferred to C3N4 compared to L-Au, which can promote water to generate H2.

[0075] To explain the hydrogen generation reaction in more detail, g-C3N4 is excited by the irradiated light, generating excited holes and electrons. These can be collectively expressed as hot carriers. Chiral gold nanoparticles bonded to g-C3N4 are also excited simultaneously by the irradiated light, and the excitation at this time can be named plasmonic excitation. The degree of plasmonic excitation varies depending on the alignment of the polarization direction of the irradiated light and the chiral direction of the chiral gold nanoparticles. When the direction is aligned, the excitation is strengthened, and when the direction is misaligned, it is weakened. The spin-oriented hot carriers generated at this time are injected into g-C3N4 to directly participate in the hydrogen generation reaction, or recombine with the excited holes of g-C3N4 to eliminate the excited holes. At this time, methanol used as a sacrificial reagent provides electrons to chiral gold nanoparticles, thereby assisting in their reduction. Ultimately, hydrogen evolution proceeds through spin-aligned hot carriers accumulated in g-C3N4, and the rate of the hydrogen evolution reaction is determined by the amount of spin-aligned hot carriers.

[0076] Figure 4 shows the polarization-dependent hydrogen production reaction results of chiral plasmonic photocatalysts, L-Au / C3N4 (a), R-Au / C3N4 (b), and (c) 0-Au / C3N 4-The H2 production over time under LCP, RCP, and LP irradiation is shown. Figure 4d shows the comparison of the hydrogen production per hour. Under LCP, RCP, and LP, L-Au / C3N4 showed hydrogen production efficiencies of 1.252 μmol / g·h, 0.616 μmol / g·h, and 0.509 μmol / g·h, respectively, and R-Au / C3N4 showed efficiencies of 0.599 μmol / g·h, 1.270 μmol / g·h, and 0.423 μmol / g·hg, respectively. Finally, 0-Au / C3N 4- It showed efficiencies of 0.636 μmol / g·h, 0.640 μmol / g·h, and 0.733 μmol / g·h under LCP, RCP, and LP, respectively.

[0077] That is, chiral plasmonic photocatalysts interact more strongly with circularly polarized light in a specific direction, which can promote the generation of excited electrons and holes, resulting in enhanced catalytic activity. Even under low-intensity circularly polarized light irradiation, chiral photocatalysts exhibited enhanced hydrogen production compared to achiral photocatalysts, and it was confirmed that the hydrogen production response varied depending on the light polarization direction.

[0078] In addition, it was confirmed through in-situ FT-IR measurements that more active interactions with water molecules were performed under circularly polarized light irradiation in a specific direction (Fig. 5). Fig. 5 shows a schematic diagram of the in-situ FT-IR aspect (a), a change in transmittance obtained from real-time FT-IR spectra of each sample with different light irradiation conditions (b), a schematic diagram of the interaction between C3N4 and H2O molecules (c), FT-IR spectral changes according to irradiation time of LCP, LP, and RCP irradiated R-Au / C3N4 (d), and FT-IR spectral changes according to irradiation time of LCP, LP, and RCP irradiated L-Au / C3N4 (e).

[0079] To analyze the interaction between water molecules and photocatalysts in real time under CPL irradiation, an in-situ FT-IR device was designed by introducing a CPL light source as shown in (a). (b) Catalysts, methanol, and deionized water were placed together, and FT-IR was measured while irradiating each catalyst with LCP, RCP, and LP light. At this time, 2275 cm -1 The change in transmittance intensity at the (N=C=O) position is normalized and presented. When the chirality of the CPL light and the catalyst match, a greater intensity of transmittance change is observed, indicating more interactions with water molecules. (d) and (e) show the results of FT-IR measurements over time under LCP, LP, and RCP irradiation of R-Au / C3N4 and L-Au / C3N4 catalysts, respectively. (c) is a schematic representation of the possible interactions between water molecules and Au / C3N4 based on the FT-IR data, showing the bonding between molecules during the attachment and detachment process between water molecules and C3N4.

[0080] Figure 6 shows the proposed mechanism of H2 production kinetics of the polarization-dependent chiral Au / C3N4 photocatalyst of CPL, showing the steady-state PL spectrum of the photocatalyst (a) and the time-resolved PL kinetics of the photocatalyst at the corresponding steady-state emission peak (b), and a schematic diagram of the charge transfer process of R-Au / C3N4 under LCP and RCP irradiation (c).

[0081] (a) To investigate the electron-hole separation between gold nanoparticles and C3N4 support, the steady-state PL spectrum (excitation wavelength: 610 nm) was measured. A PL peak around 670 nm was observed in all R-, 0-, and L-Au / C3N4 with gold introduced, and in C3N4. The corresponding peak was not observed. (b) In addition, the time-resolved PL spectra of C3N4 and 0-Au / C3N4 with gold introduced were measured to confirm that electron transfer occurred between C3N4 and Au. (c) The electron transfer process was analyzed based on the steady-state PL and time-resolved PL data and represented according to the energy level. When irradiated with CPL, electron-hole pairs are formed in gold nanoparticles due to their plasmonic properties, and the electrons formed at this time are transferred to C3N4 and ultimately water molecules. It produces hydrogen gas by reduction. When the chirality of the catalyst and CPL match, more electrons are generated, generating more hydrogen gas and increasing the hydrogen production efficiency.

[0082] The above description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0083] The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. A substrate containing a semiconductor; and Chiral plasmonic metal nanoparticles formed on the above substrate A photocatalyst, including:

2. In paragraph 1, A photocatalyst, wherein the semiconductor comprises at least one selected from graphitic carbon nitride (g-C3N4), titanium dioxide (TiO2), and strontium titanate (SrTiO3).

3. In paragraph 1, A photocatalyst, wherein the metal nanoparticles include at least one selected from Au, Ag, Pt, Zn, Cu, Pd, Rh, Re and Rb.

4. In paragraph 1, A photocatalyst wherein the diameter of the metal nanoparticles is 10 nm to 100 nm.

5. In paragraph 1, A photocatalyst wherein the metal nanoparticles have left-handed or right-handed chirality.

6. In paragraph 1, A photocatalyst, wherein the content ratio of the metal nanoparticles in the photocatalyst is 0.01 wt% to 0.1 wt%.

7. In paragraph 1, A photocatalyst, which is a photocatalyst for hydrogen production.

8. Obtaining a mixture comprising a substrate including a semiconductor and a metal precursor; and A method for producing a photocatalyst, comprising irradiating the above mixture with circularly polarized light to grow chiral plasmonic metal nanoparticles on the above substrate.

9. In paragraph 8, A method for producing a photocatalyst, wherein the semiconductor comprises at least one selected from graphitic carbon nitride (g-C3N4), titanium dioxide (TiO2), and strontium titanate (SrTiO3).

10. In paragraph 8, A method for producing a photocatalyst, wherein the metal nanoparticles include at least one selected from Au, Ag, Pt, Zn, Cu, Pd, Rh, Re and Rb.

11. In paragraph 8, A method for producing a photocatalyst, wherein the above mixture further comprises a sacrificial reagent.

12. In paragraph 11, A method for producing a photocatalyst, wherein the sacrificial reagent comprises methanol.

13. In paragraph 8, When left-handed circularly polarized light is applied, metal nanoparticles with left-handed chirality are grown. A method for producing a photocatalyst, wherein metal nanoparticles having right-handed chirality are grown when right-handed circularly polarized light is irradiated.

14. Contacting a photocatalyst with water and irradiating it with circularly polarized light to obtain hydrogen. A method for producing hydrogen, comprising: A method for producing hydrogen, wherein the photocatalyst comprises a substrate including a semiconductor; and chiral plasmonic metal nanoparticles formed on the substrate.

15. In paragraph 14, A method for producing hydrogen, wherein the metal nanoparticles have left-handed or right-handed chirality.

16. In paragraph 14, A method for producing hydrogen, wherein the above circular polarization is left-hand circular polarization or right-hand circular polarization.

17. In paragraph 14, When the above metal nanoparticles have left-handed chirality, hydrogen is generated by irradiating left-handed circularly polarized light. A method for producing hydrogen, wherein hydrogen is produced by irradiating right-handed circularly polarized light when the above metal nanoparticles have right-handed chirality.

18. In paragraph 14, The hydrogen production rate is 1.2 μmol g -1 h -1 A method for producing hydrogen, which is an ideal thing.

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