Nuclear defect alloy nanocluster and application thereof in hydrogen production through water photolysis

Abstract

The invention discloses a nuclear defect alloy nanocluster and application thereof in hydrogen production through water photolysis, and belongs to the technical field of nano materials. The molecular formula of the core defect alloy nanocluster is Pt1Ag11 (SR) 5 (P (Ph-OMe) 3) 7, and is simply recorded as Pt1Ag11; wherein R < R > represents 2, 3, 5, 6-tetrafluorothiophenol, and P (Ph-OMe) < 3 > represents tris (4-methoxyphenyl) phosphine. According to the invention, hydrogen evolution reaction (HER) is taken as a model, and the influence of the nuclear structure defect composite material on the photocatalytic hydrogen production performance is explored. The Pt1Ag11 / g-C3N4 has good performance of producing hydrogen through water photolysis, which is caused by the fact that the Pt1Ag11 / g-C3N4 has higher photocurrent density and higher electron transmission speed, so that combination of electrons and holes is effectively inhibited.

Description

Technical Field

[0001] The invention relates to the technical field of nanomaterials, and in particular to a core defect alloy nanocluster and application thereof in hydrogen production by photolysis of water. Background Art

[0002] Photocatalytic water splitting to produce hydrogen has attracted widespread attention as it provides a pollution-free and sustainable way to alleviate the energy crisis and solve environmental problems. Due to the complex processes involved in photocatalytic reactions, including light absorption, charge separation, transport, dissociation, and recombination, achieving high conversion efficiency remains a major challenge. Therefore, the demand for developing efficient photocatalysts for photocatalytic hydrogen production is very high.

[0003] Metal nanoclusters (NCs) with atomic precision (1-3 nm in diameter) show potential application value in the field of photocatalysis due to their unique atomic stacking patterns, optical properties and abundant catalytic active sites. In addition, the ultra-small size gives metal NCs discrete electronic energy levels, similar to molecular behavior, and they themselves act as small bandgap semiconductors that can be excited to produce electrons and holes. In order to prevent the unfavorable agglomeration of metal NCs due to high surface energy during the photocatalytic reaction, composite photocatalysts based on NCs were prepared to improve the catalytic stability and activity. In 2013, Negishi et al. reported the use of glutathione-protected Au 25 Nanoclusters (NCs) loaded on BaLa4Ti4O 15 As a mixed catalyst for water splitting reaction, its photocatalytic activity is 2.6 times higher than that of the co-catalyst loaded with larger gold nanoparticles (10-30 nm). Since then, various metal nanoclusters have been applied in photocatalytic hydrogen production. For example, Lu et al. synthesized Pt5(GSH) 10 The Pt nanoclusters were fixed on multi-arm CdS nanorods (NRs). The study found that the Pt nanoclusters were able to extract the photoinduced electrons of the CdS nanorods and enhance the charge separation, so that the Pt5-CdS composite catalyst showed improved photocatalytic H2 performance with a H2 production rate of 13.0 mmol . g -1. h -1 In addition, Wang et al. synthesized Ag 44 NCs and immobilized them on titanium dioxide. 44 -TiO2 photocatalytic H2 production was 7.4 mmol . g - 1. h -1 . Ag 44The high performance of -TiO2 is attributed to the extension of the photoresponse and the efficient separation and transport of carriers. In addition, previous studies have shown that the introduction of vacancy defects in the NCs structure can significantly improve the catalytic performance. For example, Cu with a vacancy defect at the top of the structure 28 NCs, the vacancies lead to framework distortion, reducing its symmetry, and 29 + Compared with the conventional hydride-containing 2-electron palladium / copper superatom alloy, PdHCu 11 and PdHCu 12 Among them, PdHCu 11 The unique vacancy defect structure exposes the central Pd and provides an active site for the catalytic reaction. 11 The present invention provides a core defect alloy nanocluster and its application in hydrogen production by photolysis of water. Summary of the invention

[0004] The present invention provides a core defect alloy nanocluster and its application in photocatalytic hydrogen production by water splitting. The present invention uses the hydrogen evolution reaction (HER) as a model to explore the influence of the core structure defect composite material on the photocatalytic hydrogen production performance. 11 / g-C3N4 has good performance in photocatalytic water splitting to produce hydrogen, which may be the 11 / g-C3N4 has a higher photocurrent density and faster electron transfer speed, which effectively inhibits the combination of electrons and holes. The present invention describes the influence of defect cluster composite materials on photolysis of water to produce hydrogen, and provides ideas for the rational design of efficient photocatalysts.

[0005] The core defect alloy nanocluster of the present invention has the molecular formula of Pt1Ag 11 (SR)5(P(Ph-OMe)3)7, abbreviated as Pt1Ag 11 Wherein, SR represents 2,3,5,6-tetrafluorobenzenethiol, and P(Ph-OMe)3 represents tri(4-methoxyphenyl)phosphine.

[0006] The core defect alloy nanocluster of the present invention consists of a defective Pt1Ag9 core surrounded by five P(Ph-p-OMe)3 ligands, one Ag(SR)2(P(Ph-OMe)3) motif and one Ag(SR)3(P(Ph-OMe)3) motif.

[0007] The method for preparing the core defect alloy nanoclusters of the present invention comprises the following steps: Silver salt and platinum metal source are dissolved in methanol, stirred at room temperature, and 2,3,5,6-tetrafluorobenzenethiol is added, and the color of the solution changes from yellow transparent to black to milky yellow turbid; in the initial reaction, tri(4-methoxyphenyl)phosphine is added, stirred, and the color of the solution changes to yellow transparent; sodium borohydride is added, and the reaction is carried out in a protective atmosphere at room temperature in the dark to obtain a two-phase solution including an organic phase and an aqueous phase, and the organic phase is crystallized at room temperature to obtain the alloy nanoclusters.

[0008] The silver salt is silver nitrate; the platinum metal source is chloroplatinic acid hexahydrate.

[0009] The usage ratio of the silver salt, the platinum metal source, 2,3,5,6-tetrafluorobenzenethiol, tri(4-methoxyphenyl)phosphine and sodium borohydride is 40 mg:60 µL:40 µL:10 mL (200 mg):80 mg.

[0010] As a preferred embodiment, the initial reaction time is 5 min, and the light-proof reaction time is 12 h.

[0011] As a preferred embodiment, the organic phase is washed with water and methanol, and the organic phase is washed with dichloromethane / n-hexane (V 二氯甲烷 :V 正己烷 =1:4) and the organic phase is crystallized.

[0012] The invention discloses an application of the core defect alloy nanoclusters in the production of hydrogen by photolysis of water.

[0013] Specifically, the core defect alloy nanoclusters are loaded on a carrier and then catalyzed to photolyze water to produce hydrogen.

[0014] Furthermore, the carrier is g-C3N4 nanosheets.

[0015] Further, the loading process includes the following steps: 5 mg Pt1Ag 11 The nanoclusters were dissolved in dichloromethane and the solution was orange in color. 100 mg of g-C3N4 was added to the orange solution and the mixture was stirred for 12 h. The color of the supernatant turned colorless when the nanoclusters were successfully embedded in the g-C3N4. The reaction mixture was then centrifuged at 8000 rpm for 10 min to remove the transparent DCM layer and the g-C3N4 precipitate was dried in vacuum to obtain 5 wt% Pt1Ag 11 / g-C3N4 catalyst.

[0016] A 300W Xe lamp was used as a visible light source. 50 mg of the prepared photocatalyst was ultrasonically dissolved in 20 mL of triethanolamine (TEOA, sacrificial reagent) and 80 mL of water and then loaded into a 250 mL sealed quartz reactor. Before turning on the Xe lamp, the system was in complete vacuum. An online gas chromatograph (GC-5190, China) was used to sample and analyze hydrogen, with argon as the carrier gas. The temperature of the whole process was maintained at 8 °C by circulating cooling water.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The alloy nanoclusters of the present invention, namely Pt1Ag 11 (SR)5(P(Ph-OMe)3)7(Pt1Ag 11 ), consisting of a defective Pt1Ag9 core surrounded by five P(Ph-OMe)3 ligands, one Ag(SR)2(P(Ph-OMe)3) motif and one Ag(SR)3(P(Ph-OMe)3) motif. This paper uses the hydrogen evolution reaction (HER) as a model to explore the effect of core structure defect composite materials on the photocatalytic hydrogen production performance. Pt1Ag 11 / g-C3N4 has good performance in photocatalytic water splitting to produce hydrogen, which may be the 11 / g-C3N4 has a higher photocurrent density and faster electron transfer speed, which effectively inhibits the combination of electrons and holes. The present invention not only understands the influence of defect clusters on photolysis of water to produce hydrogen, but also provides ideas for the rational design of efficient photocatalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Pt1Ag 11 Structural analysis of .

[0019] Figure 2 Pt1Ag 11 ESI-MS results, inset: experimental (black) and simulated (red, blue) isotope patterns.

[0020] Figure 3 Pt1Ag 11 UV-vis results.

[0021] Figure 4 Pt1Ag 11 XPS graph of Pt1Ag. 11 ; (b) Pt 4f; (c) Ag 3d.

[0022] Figure 5 Pt1Ag 11Space-filling model diagram of the kernel; Figure 6 Pt1Ag 11 Bond lengths of (a) Pt-Ag, (b) Ag-Ag, (c) Ag-S and (d) Ag-P, (e) Pt-P.

[0023] Figure 7 Pt1Ag 11 TEM image of / g-C3N4, the average size is 1.16nm.

[0024] Figure 8 g-C3N4, Pt1Ag 11 , Pt1Ag 11 / g-C3N4 hydrogen production performance diagram.

[0025] Fig. 9 For g-C3N4 and Pt1Ag 11 UV-vis and Tauc plot of / g-C3N4.

[0026] Fig.10 For g-C3N4 and Pt1Ag 11 Photocurrent density diagram, EIS diagram, PL diagram and luminescence lifetime decay curve diagram of / g-C3N4. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solution of the present invention and implement it, the present invention is further described below in conjunction with specific embodiments and drawings, but the embodiments are not intended to limit the present invention. The following test methods and detection methods, unless otherwise specified, are conventional methods; the reagents and raw materials, unless otherwise specified, are commercially available.

[0028] Photocatalytic water decomposition to produce hydrogen has attracted widespread attention because it provides a pollution-free and sustainable way to alleviate the energy crisis and solve environmental problems. Since the processes involved in photocatalytic reactions are complex, including light absorption, charge separation, transmission, dissociation and recombination, achieving high conversion efficiency remains a major challenge. Therefore, the demand for developing efficient photocatalytic hydrogen production photocatalysts is very high. In response to the above problems, the present invention provides a PtAg alloy nanocluster, which uses silver salt, platinum group metal source, and 2,3,5,6-tetrafluorobenzenethiol as raw materials for initial reaction, and then adds tri(4-methoxyphenyl)phosphine, stirs, adds sodium borohydride, and reacts in a protective atmosphere at room temperature in the dark to obtain a two-phase solution comprising an organic phase and an aqueous phase, and the organic phase is crystallized at room temperature to obtain an alloy nanocluster.

[0029] The present invention obtains Pt1Ag 11Nanoclusters, the above nanoclusters are composed of a defective Pt1Ag9 core, surrounded by 5 P(Ph-OMe)3 ligands, 1 Ag(SR)2(P(Ph-OMe)3) motif and 1 Ag(SR)3(P(Ph-OMe)3) motif. The present invention uses the hydrogen evolution reaction (HER) as a model to explore the effect of core structure defect composite materials on the photocatalytic hydrogen production performance. Pt1Ag 11 / g-C3N4 has good performance in photocatalytic hydrogen production from water, which may be due to its higher photocurrent density and faster electron transfer speed, thereby effectively inhibiting the combination of electrons and holes. The present invention not only understands the influence of defect clusters on photocatalytic hydrogen production from water, but also provides ideas for the rational design of efficient photocatalysts.

[0030] The effects are described below in conjunction with the specific test process and preparation method.

[0031] Experimental chemicals: chloroplatinic acid hexahydrate (H2PtCl6·6H2O, 99.99%), silver nitrate (AgNO3, 98%), 2,3,5,6-tetrafluorothiophenol, sodium borohydride (NaBH4) and tri(4-methoxyphenyl)phosphine (P(Ph-OMe)3) were purchased from Shanghai MacLean Biochemical Co., Ltd. Solvents including dichloromethane (DCM, HPLC grade), methanol (MeOH, HPLC grade) and n-hexane (n-HeX, HPLC grade) were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Ultrapure water used in this study was purified on a microporous system. Embodiment 1:

[0032] A Pt1Ag 11 The method for preparing alloy nanoclusters comprises the following steps: In a 50 mL round-bottom flask, 40 mg of silver nitrate was dissolved in 10 mL of methanol, and 60 µL of chloroplatinic acid hexahydrate (concentration of 0.2 g / ml) was added. The solution was stirred vigorously at room temperature for 10 min, and the solution immediately turned yellow. 40 µL of 2,3,5,6-tetrafluorothiophenol was added to the round-bottom flask, and the reaction was continued for 5 min. 200 mg of tri(4-methoxyphenyl)phosphine dissolved in 10 mL of dichloromethane was added, and the color of the solution became transparent. After vigorous stirring for 30 min, 2 mL of sodium borohydride (40 mg / mL) aqueous solution was added, and the color of the solution immediately changed from yellow to black. The solution was reacted for 12 h at room temperature in a nitrogen atmosphere in the dark to obtain a two-phase solution containing an organic phase and an aqueous phase. The aqueous phase was removed, and the organic phase was washed with water and methanol. At room temperature, dichloromethane / n-hexane was used for crystallization, and orange rhombohedral single crystals were formed after 7 days to obtain Pt1Ag 11 Alloy nanoclusters, namely Pt1Ag11 (SR)5(P(Ph-OMe)3)7. Embodiment 2:

[0033] A method for preparing a carrier g-C3N4 nanosheet comprises the following steps: The original g-C3N4 was synthesized by thermal polymerization. 5 g of melamine was calcined at 550 °C for 4 h at a rate of 5 °C / min. Then, the obtained yellow sample was collected and spread in a crucible and then calcined at 500 °C for 2 h at a heating rate of 5 °C / min to obtain g-C3N4 nanosheets. Embodiment 3:

[0034] During the loading process, 5 mg Pt1Ag 11 The nanoclusters were dissolved in dichloromethane in a round-bottom flask and the solution color was orange. In the orange solution, 100 mg of g-C3N4 was added and the mixture was stirred for 12 h. The color of the supernatant turned colorless when the nanoclusters were successfully embedded on the g-C3N4. The reaction mixture was then centrifuged at 8000 rpm for 10 min. The transparent DCM layer was removed and the g-C3N4 precipitate was dried in vacuum for several hours. The dry powder was characterized by transmission electron microscopy analysis and used for catalytic reactions.

[0035] For the Pt1Ag prepared above 11 The performance of (SR)5(P(Ph-OMe)3)7 alloy nanoclusters was tested. The specific process and results are as follows: 1. Test methods 1. Electrospray ionization time-of-flight mass spectrometry (ESI-MS) measurements were performed using a Waters XEVO G2-XS Qtof mass spectrometer. The sample was directly injected into the chamber at a rate of 5 μL / min. To prepare the ESI sample, the nanoclusters were dissolved in dichloromethane (1 mg / mL) and then diluted with methanol (V / V = 1:1).

[0036] 2. The UV-visible absorption spectra of all nanoclusters were recorded using an Agilent 8453, the samples were dissolved in CH2Cl2, and the background correction was performed using a CH2Cl2 blank sample. In addition, the UV-visible diffuse reflectance spectra (DRS) were measured at room temperature using a Shimadzu UV-2600i spectrophotometer with BaSO4 as reference.

[0037] 3. The morphology of the samples was studied using transmission electron microscopy (TEM, JEM-2010).

[0038] 4. X-ray photoelectron spectroscopy (XPS) measurements were performed on a thermal scale ESCALAB 250 equipped with a monochromatic aluminum Kα (1486.8 Ev) 150 W X-ray source, 0.5 mm circular spot size and a flow ejector.

[0039] 5. Electrochemical impedance spectroscopy (EIS) and photocurrent time spectrum were recorded on a CHI760E electrochemical workstation using a standard three-electrode system, in which the photocatalyst-coated doped fluorinated tin oxide (FTO) was used as the working electrode, the Pt plate was used as the counter electrode, and the saturated Ag / AgCl electrode was used as the reference electrode. During the measurement, we used a 300 W xenon lamp MC-PF300C (Beijing Merry Change) and a 420 nm cutoff filter as the light source. The electrolyte was a 0.2 M sodium sulfate solution. The synthesized sample (10 mg) was added to a mixed solution of 400 μL ethanol and 20 μL Nafion, and the suspension (200 μL) was dropped onto the FTO glass substrate and dried at room temperature to prepare the working electrode.

[0040] 6. The photoluminescence (PL) spectra were measured using a HORIBA Fluorescence Max+ fluorescence spectrometer with the same optical density (OD) of ~ 0.05.

[0041] 7. The emission lifetime of nanoclusters was measured on the HORIBA FluoroMax-4P. The nanoclusters were purified with N2 for 5 min and then saturated with O2 for 5 min to obtain the corresponding UV-visible absorption, PL spectrum and emission lifetime. Both N2 and O2 gases were ultra-high purity.

[0042] (II) Test results 1. Pt1Ag 11 Synthesis and characterization of nanoclusters Pt1A 11 A one-pot synthesis method was used, as described in the preparation method of Example 1. The structural analysis of the alloy nanoclusters is shown in Figure 1 As shown, it consists of a defective Pt1Ag9 core surrounded by five P(Ph-p-OMe)3 ligands, one Ag(SR)2(P(Ph-OMe)3) motif and one Ag(SR)3(P(Ph-OMe)3) motif.

[0043] Electrospray ionization mass spectrometry (ESI-MS) was used in positive ion mode to identify Pt1Ag 11 The chemical composition of Pt1Ag 11 In the ESI-MS spectrum, two strong signals were observed at m / z = 2500.726 and 2511.792Da. Figure 2, corresponding to Pt1Ag 11 (C6HF4S)5(C 21 H 21 O3P)7Ag2(CH3OH) and Pt1Ag 11 (C6HF4S)5(C 21 H 21 O3P)7Ag2(CH3ONa) (calculated m / z = 2500.765 and 2511.755 Da, respectively). The results obtained from the experiment and simulation are found to be in good agreement, indicating that Pt1Ag 11 The nanoclusters are charge neutral. Pt1Ag 11 The UV-visible absorption spectrum in CH2Cl2 is as follows Figure 3 Pt1Ag 11 It shows a strong peak centered at 372 nm and three weak shoulders at 425, 455, and 550 nm.

[0044] In addition, X-ray photoelectron spectroscopy confirmed that 11 There are Pt, Ag, P, F, O, S and C in Pt1Ag 11 The center of Ag3d at 368.2 eV shows a zero valence state; 5 / 2 The peak indicates that the valence state of Ag is between Ag (0) and Ag (I), such as Figure 4 shown.

[0045] Single crystal X-ray crystallography results show that Pt1Ag 11 use P-1 space groups, as shown in Table 1. Compared with the Pt1Ag reported by Huang et al. 14 Icosahedral Pt1Ag 12 Compared with the core, it shows different icosahedral core defects, such as Figure 5 In addition, we also analyzed Pt1Ag 11 The bond length of NC. The length of Pt-Ag ranges from 2.695 to 2.787 Å (average 2.743 Å), the length of Ag-Ag ranges from 2.781 to 2.951 Å (average 2.861 Å); the length of Ag-P ranges from 2.416 to 2.493 Å (average 2.448 Å), the length of Ag-S ranges from 2.442 to 2.673 Å (average 2.532 Å), and the length of Pt-P is 2.263 Å, as shown in Figure 6 shown.

[0046] Table 1 is Pt1Ag 11 Crystallographic data and structural optimization of nanoclusters, Pt1Ag 11The CCDC number of (SR)5(P(Ph-OMe)3)7 is 2380779.

[0047]

[0048] 2. Pt1Ag 11 Synthesis and Characterization of / g-C3N4 Composites The present invention adopts photocatalytic hydrogen evolution reaction to study Pt1Ag 11 The effect of NC introduction on photocatalytic activity. First, layered g-C3N4 with a large specific surface area was synthesized by secondary calcination; and Pt1Ag 11 NC anchored on g-C3N4 photocatalyst to prepare Pt1Ag 11 / g-C3N4 composite material. Transmission electron microscopy (TEM) images show that Pt1Ag 11 The presence and uniform distribution of NC on g-C3N4, such as Figure 7 shown.

[0049] 3. Pt1Ag 11 Photocatalytic test of / g-C3N4 composites Different loading amounts of Pt1Ag 11 The hydrogen evolution performance of / g-C3N4 was tested under the full solar spectrum conditions, and the results showed that the optimal loading was 5 wt%. When 20 wt% triethanolamine (TEOA) was used as a sacrificial agent, Pt1Ag 11 / g-C3N4 has the highest hydrogen production performance (1780 μmol . g -1. h -1 ), which is 33.65 times that of the original g-C3N4 (52.9 μmol . g -1. h -1 ), for Pt1Ag 11 27.9 times (63.8 μmol . g -1. h -1 ),like Figure 8 shown.

[0050] 4. Pt1Ag 11 Mechanism of improved photocatalytic hydrogen evolution performance of g-C3N4 composites like Fig. 9 As shown, compared with pure g-C3N4, Pt1Ag 11 / g-C3N4 has enhanced light absorption intensity. This is conducive to the excitation of more photoelectrons to improve the photocatalytic activity, thereby improving the photocatalytic H2 evolution performance. In addition, in order to clarify the 11 / g-C3N4 composites have superior photocatalytic hydrogen evolution performance and explore the reasons for their significantly improved catalytic performance, such as Fig.10 As shown in Figure 2, we conducted a series of photoelectrochemical experiments to explore the electron-hole separation and electron transfer behavior of the composite photocatalyst. 11 / g-C3N4> g-C3N4, indicating that Pt1Ag 11 / g-C3N4 has a strong response, which promotes the separation of electron and hole pairs. The electrochemical impedance spectroscopy (EIS) of the composite material was tested to determine the interfacial charge transfer efficiency. As shown in the Nyquist curve, Pt1Ag 11 The charge transfer resistance of Pt1Ag / g-C3N4 is much smaller than that of g-C3N4. 11 / g-C3N4 composites have stronger electron transfer ability and higher current density. Under 373 nm excitation, the steady-state photoluminescence (PL) spectrum shows that g-C3N4 and Pt1Ag 11 The Pt1Ag / g-C3N4 composite has a broadband center at around 450 nm with significantly different PL intensity. The decrease in PL intensity in the composite reflects the electron transfer from g-C3N4 to Pt1Ag 11 NCs are effectively transferred. In addition, we also measured the time-resolved PL spectra to study the efficiency of electron transfer. The fitting of the time-resolved PL spectra determines the PL lifetime; among them, g-C3N4 and Pt1Ag 11 / g-C3N4 are 2.089 ns and 1.798 ns, respectively, indicating that Pt1Ag 11 NCs were loaded onto g-C3N4, thus facilitating efficient electron transfer.

[0051] In summary, the present invention designs and synthesizes a new Pt1Ag with core structure defects through ligand engineering. 11 (SR)5(P(Ph-OMe)3)7 nanoclusters. Using the hydrogen evolution reaction (HER) as a model, Pt1Ag 11 NC is loaded onto g-C3N4 to understand the effect of core structure defect composite materials on the photocatalytic hydrogen production performance. 11 / g-C3N4 has good performance in photocatalytic water splitting to produce hydrogen, which may be the 11 / g-C3N4 has a higher photocurrent density and faster electron transfer speed, which effectively inhibits the combination of electrons and holes. The present invention not only understands the influence of defect clusters on photolysis of water to produce hydrogen, but also provides ideas for the rational design of efficient photocatalysts.

[0052] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A core defect alloy nanocluster, characterized in that: The molecular formula of the core defect alloy nanocluster is Pt1Ag 11 (SR)5(P(Ph-OMe)3)7, abbreviated as Pt1Ag 11 ; Wherein, SR represents 2,3,5,6-tetrafluorobenzenethiol, and P(Ph-OMe)3 represents tri(4-methoxyphenyl)phosphine.

2. The method for preparing the core defect alloy nanoclusters according to claim 1, characterized in that The steps include: Silver salt and platinum metal source are dissolved in methanol, stirred at room temperature, and 2,3,5,6-tetrafluorobenzenethiol is added, and the color of the solution changes; in the initial reaction, tri(4-methoxyphenyl)phosphine is added, stirred, and the color of the solution changes to yellow and transparent; then sodium borohydride is added, and the reaction is carried out in a protective atmosphere at room temperature in the dark to obtain a two-phase solution including an organic phase and an aqueous phase, and the organic phase is crystallized at room temperature to obtain core defect alloy nanoclusters.

3. The preparation method according to claim 2, characterized in that: The silver salt is silver nitrate; the platinum metal source is chloroplatinic acid hexahydrate.

4. The preparation method according to claim 2, characterized in that: The organic phase is washed with water and methanol, and crystallized with a mixed solution of dichloromethane and n-hexane.

5. Use of the core-defect alloy nanoclusters described in claim 1 in catalytic photolysis of water to produce hydrogen.

6. The use according to claim 5, characterized in that: The core defect alloy nanoclusters are loaded on carrier g-C3N4 nanosheets and then catalyzed to photolyze water to produce hydrogen.

7. The use according to claim 6, characterized in that: The loading process includes the following steps: 11 The nanoclusters were dissolved in dichloromethane and the solution was orange in color. g-C3N4 was added to the orange solution and the mixture was stirred. When the nanoclusters were successfully embedded in the g-C3N4, the color of the supernatant turned colorless. The reaction mixture was then centrifuged and the g-C3N4 precipitate was dried in vacuum to obtain Pt1Ag 11 / g-C3N4 catalyst.

8. The use according to claim 6 or 7, characterized in that: The Pt1Ag 11 The loading amount of the core-defect alloy nanoclusters in the / g-C3N4 catalyst is 5wt%.

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