Ag27 nanocluster photosensitizer, preparation method and application thereof

Abstract

This invention belongs to the interdisciplinary field of nanomaterials and coordination chemistry, and specifically relates to an Ag... 27 Nanocluster photosensitizers, their preparation methods, and applications. This Ag... 27 The chemical formula of the nanocluster photosensitizer is C 170 H 167 Ag 27 Cl2N 18 O6P7, abbreviated as Ag 27 (DPCA)6(DPP)3(DPPB)2(Ac)3Cl2, belonging to the monoclinic crystal system; space group C2, α=90°, β=112.278(7)°, γ=90°, Ag 27 Ag, a composite photocatalyst formed by nanocluster photosensitizers and TiO2 27 TiO2 not only possesses excellent hydrogen production activity, but it can also oxidize methanol sacrificial agents into formaldehyde, a high-value-added product. Under 365nm LED illumination, 1% Ag... 27 The photocatalytic hydrogen production rate of TiO2 and the formaldehyde content in the solution are 12.13 times and 10.70 times that of TiO2, respectively, indicating good application prospects.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary field of nanomaterials and coordination chemistry, and in particular relates to an Ag... 27 Nanocluster photosensitizers, their preparation methods, and applications. Background Technology

[0002] With the increasing depletion of fossil fuel resources and the intensification of global warming, human energy supply is gradually shifting from reliance on fossil fuels to clean and renewable energy. Hydrogen, as an ideal clean energy carrier, produces only water during combustion with no pollutant emissions, and is considered a highly promising future alternative energy source. Sunlight, as one of the largest renewable energy sources on Earth, is also considered a cleaner and more efficient sustainable method for hydrogen production through photocatalysis. Among numerous photocatalytic materials, TiO2 is considered an ideal environmentally friendly photocatalytic material due to its stable chemical properties, high melting point, ease of doping and modification, non-toxicity, and low cost. However, despite TiO2's excellent physicochemical properties, the easy recombination of photogenerated electrons and holes leads to a shorter lifetime for photogenerated carriers, thus limiting its photocatalytic performance.

[0003] In recent years, atomically precise metal nanoclusters have emerged as a new class of photosensitizers. They not only possess strong absorption capabilities for visible light but also exhibit high specific surface area and abundant surface active sites. Composite photocatalytic materials formed by loading these nanoclusters onto TiO2 show significantly enhanced photogenerated electron-hole separation capabilities and photocatalytic performance. In particular, their precisely defined atomic structure provides an ideal model for in-depth research into the complex relationship between catalyst structure and performance. For example, Tian et al. used structurally precise Ni6(SCH2Ph) nanoclusters… 12 Nanoclusters uniformly loaded on TiO2 nanoparticles achieved a photocatalytic hydrogen evolution rate of 5.6 mmol·h⁻¹. -1 ·g -1 Bootharaju et al. used atomically precise [Au] 12 Ag 32 (SePh) 30 ] 4- Nanoclusters loaded on the TiO2 surface exhibited a photocatalytic hydrogen production activity of 6.810 mmol·h⁻¹. -1 ·g -1 Wang et al. used precisely structured Ag 44 (SR) 30 Nanoclusters loaded on TiO2 exhibit a photocatalytic rate of 7.4 mmol·h⁻¹ for H₂ generation. -1 ·g -1However, existing literature reports that precisely structured metal nanoclusters, when used as photosensitizers in composite photocatalytic materials formed with TiO2, exhibit low photocatalytic activity and generally low hydrogen production rates. Therefore, developing precisely structured metal nanocluster photosensitizers capable of forming high-performance composite photocatalytic materials with TiO2 to enhance photocatalytic activity and achieve efficient photocatalytic hydrogen production has become a crucial issue that urgently needs to be addressed. Summary of the Invention

[0004] One of the objectives of this invention is to provide an Ag 27 Nanocluster photosensitizers effectively solve the technical problem that existing metal nanocluster photosensitizers are difficult to form high-performance composite photocatalytic materials with TiO2 for efficient photocatalytic hydrogen production. This is because Ag... 27 The nanocluster photosensitizer exhibits strong absorption around 365 nm, thus effectively exciting Ag under LED illumination at a wavelength of 365 nm. 27 The transition of electrons from the ground state to the excited state in nanocluster photosensitizers is beneficial for TiO2 supports to improve the efficiency of photogenerated electron-hole separation, thereby achieving efficient photocatalytic hydrogen production.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: an Ag 27 Nanocluster photosensitizer, the Ag 27 The chemical formula of the nanocluster photosensitizer is C 170 H 167 Ag 27 Cl2N 18 O6P7 is composed of 27 Ag atoms, 3 DPP organic ligands, 6 DPCA organic ligands, 2 DPPB organic ligands, 3 Ac ligands, and 2 Cl halogen ligands, abbreviated as Ag. 27 (DPCA)6(DPP)3(DPPB)2(Ac)3Cl2 belongs to the monoclinic crystal system; space group C2. α=90°, β=112.278(7)°, γ=90°, The molecular weight is 5758.39 Da;

[0006] Among them, the organic ligand DPCA is deprotonated bis(2-pyridylmethyl)amine, the organic ligand DPP is deprotonated diphenylphosphine hydrogen, the organic ligand DPPB is 1,4-bis(diphenylphosphine)butane, and the ligand Ac is CH3COO. - The structural formulas of the organic ligands DPP, DPCA, and DPPB are shown in the following figures:

[0007]

[0008] As Ag 27 Further improvements to nanocluster photosensitizers:

[0009] Preferably, the Ag 27 Two twisted Ag atoms in the nanocluster photosensitizer 13 Icosahedrons are formed by fusing together shared triangular faces to form Ag. 23 The remaining 4 Ag atoms are respectively with Ag 23 The two Ag atoms in the core, the P atom in the diphenylphosphine ligand, and the two N atoms in the bis(2-pyridylmethyl)amine ligand coordinate to form four μ5-Ag sites. 23 Together with four μ5-Ag atoms, they form the cluster core Ag. 27 .

[0010] The second objective of this invention is to provide any one of the Ag claims. 27 The preparation method of the nanocluster photosensitizer includes the following steps:

[0011] S1. Dissolve the silver salt in a mixed solvent of dichloromethane and methanol, add monophosphine ligand and bisphosphine ligand, stir, then add nitrogen ligand and acetic acid, continue stirring thoroughly, add sodium borohydride aqueous solution, and stir thoroughly at room temperature in the dark to obtain a clear green solution.

[0012] S2. Using diethyl ether as a dispersant, gas-phase diffusion is carried out into a clear green solution to obtain crystals. The crystalline product is collected, washed with diethyl ether, and then dried under vacuum to obtain Ag. 27 Nanocluster photosensitizer.

[0013] As Ag 27 The preparation method of nanocluster photosensitizers has been further improved:

[0014] Preferably, the molar mass ratio of the silver salt, monophosphine ligand, bisphosphine ligand, nitrogen ligand, acetic acid, and sodium borohydride contained in the sodium borohydride aqueous solution is 1:(0.6-1.3):(1.2-1.7):(0.4-1):(2-4):(12-20).

[0015] Preferably, in step S1, the mixed solvent of dichloromethane and methanol is formed by mixing dichloromethane and methanol in a volume ratio of (4-5):1.

[0016] Preferably, in step S1, the concentration of the silver salt in the mixed solvent of dichloromethane and methanol is 0.009-0.012 mmol / ml.

[0017] Preferably, the silver salt is silver trifluoromethanesulfonate; or, the monophosphine ligand is diphenylphosphine hydrogen; or, the bisphosphine ligand is 1,4-bis(diphenylphosphine)butane; or, the nitrogen ligand is bis(2-pyridylmethyl)amine.

[0018] The second objective of this invention is to provide any one of the Ag claims. 27 Application of nanocluster photosensitizers in photocatalytic hydrogen production.

[0019] As Ag 27 Further improvements have been made to the application of nanocluster photosensitizers in photocatalytic hydrogen production:

[0020] Preferably, Ag 27 Nanoclusters of photosensitizers loaded on TiO2 are used for photocatalytic hydrogen production.

[0021] Preferred, Ag 27 The loading rate of the nanocluster photosensitizer on TiO2 was 1%.

[0022] The advantages of this invention compared to the prior art are as follows:

[0023] 1) This invention provides a structurally precise Ag 27 Nanocluster photosensitizer, chemical formula C 170 H 167 Ag 27 Cl2N 18 O6P7, Ag 27 The nanocluster photosensitizer exhibits strong absorption around 365 nm, thus effectively exciting Ag under LED illumination at a wavelength of 365 nm. 27 The transition of electrons from the ground state to the excited state in nanocluster photosensitizers is beneficial for TiO2 supports to improve the efficiency of photogenerated electron-hole separation, thereby achieving efficient photocatalytic hydrogen production.

[0024] 2) This invention provides an Ag 27 The preparation method of nanocluster photosensitizers utilizes both flexible ligands: a nitrogen ligand (bis(2-pyridylmethyl)amine) and a bisphosphine ligand (1,4-bis(diphenylphosphine)butane). The nitrogen ligand (bis(2-pyridylmethyl)amine) contains three nitrogen atoms, while the bisphosphine ligand (1,4-bis(diphenylphosphine)butane) contains two phosphine atoms. These nitrogen and phosphine atoms can form stable coordination bonds with metals, thereby stabilizing the metal clusters during catalysis. The flexible chains in both bis(2-pyridylmethyl)amine and bisphosphine ligand (1,4-bis(diphenylphosphine)butane) allow for free rotation and bending during catalysis, better adapting to different reaction environments and substrates, enhancing substrate binding energy, and improving photocatalytic efficiency.

[0025] 3) Ag of the present invention 27 Nanocluster photosensitizers can form high-performance composite photocatalytic materials Ag with TiO2. 27TiO2 not only exhibits excellent hydrogen production activity but can also oxidize methanol as a sacrificial agent into formaldehyde, a high-value-added product. Under 365nm LED illumination, with a loading rate of 1% Ag... 27 The photocatalytic hydrogen production rate of TiO2 is as high as 15.77 mmol·g. -1 ·h -1 The formaldehyde content in the solution was as high as 37.68 mmol / L, which is 12.13 times and 10.70 times that of pure TiO2 carrier without photosensitizer, respectively. Attached Figure Description

[0026] Figure 1 Ag prepared in Examples 1-5 27 Precise structure and size diagrams of nanoclusters, including Ag 27 Overall structure diagram of nanoclusters, removing Ag 27 The outer ligand diagram, Ag excluding C and H atoms 27 Diagram of coordinating atoms and Ag 27 Kernel diagram;

[0027] Figure 2 Ag prepared in Examples 1-5 27 UV-Vis absorption spectrum of nanocluster solution;

[0028] Figure 3 Ag with different loading rates prepared for Example 6 27 @Linear relationship between TiO2 hydrogen production and illumination time;

[0029] Figure 4 Ag with different loading rates prepared for Example 6 27 @TiO2 hydrogen production performance under 365nm illumination;

[0030] Figure 5 Ag with different loading rates prepared for Example 6 27 A schematic diagram illustrating the determination of formaldehyde content in the solution after photocatalytic hydrogen production using TiO2. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] Example 1

[0033] This embodiment provides an Ag 27 The preparation method of nanocluster photosensitizers specifically includes the following steps:

[0034] S1. Dissolve 15 mg of silver trifluoromethanesulfonate (0.058 mmol) in 5 mL of dichloromethane and 1 mL of methanol. Add 12 μL of diphenylphosphine hydrogen (0.069 mmol) and 40 mg of 1,4-bis(diphenylphosphine)butane (0.094 mmol). After stirring for 30 min, add 6 μL of bis(2-pyridylmethyl)amine (0.033 mmol) and 10 μL of acetic acid (0.17 mmol). After stirring thoroughly for 120 min, add 1 mL of sodium borohydride aqueous solution (concentration 30 mg / mL, containing 0.79 mmol of sodium borohydride). The solution changes from colorless to brownish-black. After stirring at room temperature for 36 h in the dark, the brownish-black solution turns into a clear green solution.

[0035] The molar ratio of silver salt, monophosphine ligand, bisphosphine ligand, nitrogen ligand, acetic acid, and sodium borohydride in the aqueous solution is 1:1.19:1.62:0.57:2.93:13.6.

[0036] S2. By using diethyl ether as a dispersant, gas-phase diffusion was carried out into a clear green solution to obtain crystals. The crystals were washed with diethyl ether, collected, and dried at room temperature to obtain Ag. 27 Nanocluster photosensitizer.

[0037] Example 2

[0038] This embodiment provides an Ag 27 The preparation method of nanocluster photosensitizers specifically includes the following steps:

[0039] S1. Dissolve 15 mg of silver trifluoromethanesulfonate (0.058 mmol) in 5 mL of dichloromethane and 1 mL of methanol. Add 10 μL of diphenylphosphine hydrogen (0.057 mmol) and 30 mg of 1,4-bis(diphenylphosphine)butane (0.070 mmol). After stirring for 30 min, add 10 μL of bis(2-pyridylmethyl)amine (0.056 mmol) and 12 μL of acetic acid (0.21 mmol). After stirring thoroughly for 120 min, add 1 mL of sodium borohydride aqueous solution (concentration 40 mg / mL, containing 1.06 mmol of sodium borohydride). The solution changes from colorless to brownish-black. After stirring at room temperature for 40 h in the dark, the brownish-black solution turns into a clear green solution.

[0040] The molar ratio of silver salt, monophosphine ligand, bisphosphine ligand, nitrogen ligand, acetic acid, and sodium borohydride in the aqueous solution is 1:0.98:1.21:0.97:3.62:18.3.

[0041] S2. By using diethyl ether as a dispersant, gas-phase diffusion was carried out into a clear green solution to obtain crystals. The crystals were washed with diethyl ether, collected, and dried at room temperature to obtain Ag. 27 Nanocluster photosensitizer.

[0042] Example 3

[0043] This embodiment provides an Ag 27 The preparation method of nanoclusters specifically includes the following steps:

[0044] S1. Dissolve 15 mg of silver trifluoromethanesulfonate (0.058 mmol) in 4 mL of dichloromethane and 1 mL of methanol. Add 11 μL of diphenylphosphine hydrogen (0.063 mmol) and 28 mg of 1,4-bis(diphenylphosphine)butane (0.066 mmol). After stirring for 30 min, add 8 μL of bis(2-pyridylmethyl)amine (0.044 mmol) and 9 μL of acetic acid (0.16 mmol). After stirring thoroughly for 120 min, add 1 mL of sodium borohydride aqueous solution (concentration 35 mg / mL, containing 0.926 mmol of sodium borohydride). The solution changes from colorless to brownish-black. After stirring at room temperature for 42 h in the dark, the brownish-black solution turns into a clear green solution.

[0045] The molar ratio of silver salt, monophosphine ligand, bisphosphine ligand, nitrogen ligand, acetic acid, and sodium borohydride in the aqueous solution is 1:1.09:1.14:0.76:2.76:16.

[0046] S2. By using diethyl ether as a dispersant, gas-phase diffusion was carried out into a clear green solution to obtain crystals. The crystals were washed with diethyl ether, collected, and dried at room temperature to obtain Ag. 27 Nanocluster photosensitizer.

[0047] Example 4

[0048] This embodiment provides an Ag 27 The preparation method of nanoclusters specifically includes the following steps:

[0049] S1. Dissolve 15 mg of silver trifluoromethanesulfonate (0.058 mmol) in 4 mL of dichloromethane and 1 mL of methanol. Add 7 μL of diphenylphosphine hydrogen (0.040 mmol) and 35 mg of 1,4-bis(diphenylphosphine)butane (0.082 mmol). After stirring for 30 min, add 4.2 μL of bis(2-pyridylmethyl)amine (0.023 mmol) and 7 μL of acetic acid (0.12 mmol). After stirring thoroughly for 120 min, add 1 mL of sodium borohydride aqueous solution (concentration 27 mg / mL, containing 0.714 mmol of sodium borohydride). The solution changes from colorless to brownish-black. After stirring at room temperature for 42 h in the dark, the brownish-black solution turns into a clear green solution.

[0050] The molar ratio of silver salt, monophosphine ligand, bisphosphine ligand, nitrogen ligand, acetic acid, and sodium borohydride in the aqueous solution is 1:0.69:1.41:0.4:2.07:12.3.

[0051] S2. By using diethyl ether as a dispersant, gas-phase diffusion was carried out into a clear green solution to obtain crystals. The crystals were washed with diethyl ether, collected, and dried at room temperature to obtain Ag. 27 Nanocluster photosensitizer.

[0052] Example 5

[0053] This embodiment provides an Ag 27 The preparation method of nanoclusters specifically includes the following steps:

[0054] S1. Dissolve 15 mg of silver trifluoromethanesulfonate (0.058 mmol) in 5 mL of dichloromethane and 1 mL of methanol. Add 13 μL of diphenylphosphine hydrogen (0.075 mmol) and 42 mg of 1,4-bis(diphenylphosphine)butane (0.098 mmol). After stirring for 30 min, add 10.5 μL of bis(2-pyridylmethyl)amine (0.058 mmol) and 13 μL of acetic acid (0.23 mmol). After stirring thoroughly for 120 min, add 1 mL of sodium borohydride aqueous solution (concentration 44 mg / mL, containing 1.16 mmol of sodium borohydride). The solution changes from colorless to brownish-black. After stirring at room temperature for 42 h in the dark, the brownish-black solution turns into a clear green solution.

[0055] The molar ratio of silver salt, monophosphine ligand, bisphosphine ligand, nitrogen ligand, acetic acid, and sodium borohydride in the aqueous solution is 1:1.29:1.69:1:3.96:20.

[0056] S2. By using diethyl ether as a dispersant, gas-phase diffusion was carried out into a clear green solution to obtain crystals. The crystals were washed with diethyl ether, collected, and dried at room temperature to obtain Ag.27 Nanocluster photosensitizer.

[0057] Take Ag obtained from Examples 1-3 27 The photosensitizer nanoclusters were further characterized as follows:

[0058] The crystals prepared in Examples 1-3 were tested using a Bruker SmartApex II CCD single-crystal X-ray diffractometer. During the testing, graphite-monochromatized Ga-Kα rays (wavelength λ = ...) were used. Using a ω-scan as the diffraction source, data were collected under nitrogen protection and at a low temperature of 193 K. The structure of the single crystal was then resolved using the ShelXT and ShelXL programs in the Olex2 software package. The refinement process employed a least-squares F2 method for optimization. Furthermore, the SADABS program was used to perform empirical absorption correction on all non-hydrogen atom positions, and the positions of these non-hydrogen atoms, including silver, nitrogen, phosphorus, chlorine, oxygen, and carbon, were directly determined. The positions of intramolecular hydrogen atoms were obtained through isotropic calculations. The resolved Ag... 27 The precise structure of nanoclusters, such as Figure 1 As shown, Ag 27 The nanocluster consists of 27 Ag atoms, 6 DPCA organic ligands, 3 DPP organic ligands, 2 DPPB organic ligands, 3 Ac ligands, and 2 Cl halogen ligands; among them, 2 are twisted Ag atoms. 13 Icosahedrons are formed by fusing together shared triangular faces to form Ag. 23 The remaining 4 Ag atoms are respectively with Ag 23 The two Ag atoms in the core, the P atom in the diphenylphosphine ligand, and the two N atoms in the bis(2-pyridylmethyl)amine ligand coordinate to form four μ5-Ag sites. 23 Together with four μ5-Ag atoms, they form the cluster core Ag. 27 The cluster size is approximately 2.2 nm. Detailed crystal measurement data are shown in Table 1.

[0059] Table 1. Main crystallographic data

[0060]

[0061]

[0062] R1=∑||Fo|-|Fc|| / ∑|Fo|.wR2=[∑w(F o 2 -F c 2 ) 2 / ∑w(F o 2 )2 ] 1 / 2

[0063] Example 6

[0064] This embodiment will use Ag 27 Composite photocatalytic materials were prepared by loading nanoclusters onto TiO2, and their photocatalytic hydrogen production performance was tested.

[0065] The Ag obtained in Example 1 27 Nanoclusters were dissolved in dichloromethane to prepare a 2 mg / mL green solution. 100 mg of commercially available TiO2 (P25) white powder was ultrasonically dispersed in 10 mL of dichloromethane to form a suspension. After continuous stirring, 250 μL, 500 μL, 1 mL, and 2 mL of Ag were added, respectively. 27 Nanocluster solution, Ag 27 The nanocluster solution rapidly changed from green to colorless, and the TiO2 powder changed from white to gray. After stirring at room temperature overnight, the suspension was centrifuged at 10,000 rpm for 3 minutes to remove the colorless and transparent upper clear solution. The gray precipitate at the bottom was dried in a vacuum drying oven to collect Ag. 27 The nanoclusters were loaded with Ag at rates of 0.5%, 1%, 2%, and 4%, respectively. 27 @TiO2 composite photocatalytic material.

[0066] A 100W LED lamp with a wavelength of 365nm was selected as the light source for the photocatalytic reaction. 10mg of Ag with different loading rates was used. 27 The TiO2 composite photocatalyst material was ultrasonically dispersed in 14 mL of methanol (used as a sacrificial agent) and 6 mL of water, and then placed in a 250 mL sealed quartz reactor. Before turning on the LED light, a nitrogen-argon mixture was purged for 30 minutes to remove air. To monitor and analyze the amount of hydrogen produced during the reaction, a GC9720 online gas chromatograph (manufactured by Fuli Instruments) was used for real-time sampling and detection, using high-purity argon as the carrier gas. Furthermore, a constant temperature circulation device was used to maintain the temperature of the entire experimental system at 50 °C. After 4 hours of illumination, the formaldehyde content after methanol oxidation was determined by liquid recovery, as follows: 1 mL of the solution from the photocatalytic hydrogen production reaction was centrifuged, and the clear supernatant was diluted 10 times; then 0.5 mL of the liquid product was mixed with 2.0 mL of water and 0.5 mL of reagent solution and shaken well, maintaining the solution at 35 °C. The colored substances in the solution were measured using a UV-Vis spectrophotometer until the intensity of the UV absorption peak at 412 nm did not increase further. The concentration of formaldehyde in the liquid product was then determined using a standard curve. The reagent solution is prepared by dissolving 15g ammonium acetate, 0.3mL acetic acid, and 0.2mL pentane-2,4-dione in 100mL of water.

[0067] The Ag prepared in Examples 1-5 27 Nanoclusters were dissolved in dichloromethane, and their UV-Vis absorption spectra were measured. Figure 2 As shown, Ag 27 The dichloromethane solution of nanoclusters exhibits ultraviolet absorption at 365 nm, 558 nm, and 623 nm, with a particularly strong absorption characteristic at 365 nm, indicating that Ag... 27 The nanocluster photosensitizer exhibits excellent response to a 365nm wavelength light source. Selecting a 365nm wavelength LED light source can effectively excite Ag. 27 The transition of electrons from the ground state to the excited state in nanocluster photosensitizers is beneficial for TiO2 supports to improve the efficiency of photogenerated electron-hole separation, thereby achieving efficient photocatalytic hydrogen production.

[0068] The loading rate of Ag was 0.5% to 4%. 27 The photocatalytic hydrogen production performance of the TiO2 composite photocatalyst material was tested under LED conditions at a wavelength of 365 nm. Figure 3 Ag with different loading rates prepared for Example 6 27 @Linear relationship between TiO2 hydrogen production and illumination time; Figure 4 Ag with different loading rates prepared for Example 6 27 @TiO2 hydrogen production performance under 365nm illumination; Figure 5 Ag with different loading rates prepared for Example 6 27 A schematic diagram illustrating the determination of formaldehyde content in the solution after photocatalytic hydrogen production using TiO2.

[0069] Figure 3 This indicates that different loading rates of Ag were used. 27 The hydrogen production of TiO2 has a good linear relationship with the duration of illumination, with the optimal loading rate being 1%. Figure 4 This indicates that when methanol is used as a sacrificial agent, 1% Ag 27 @TiO2 had the highest hydrogen production rate (15.77 mmol·g). -1 ·h -1 ), is a commercially available TiO2 carrier (1.30 mmol·g 1 ·h -1 It was 12.13 times that of [previous study]. Furthermore, liquid recovery was measured after 4 hours of illumination. Figure 5 The results showed that methanol can be oxidized into formaldehyde, a high-value-added product, using 1% Ag. 27 The formaldehyde content in the solution of the TiO2 composite photocatalyst (37.68 mmol / L) was 10.70 times that of the TiO2 support (3.52 mmol / L). These results indicate that Ag... 27Nanoclusters, as photosensitizers, significantly improve the photocatalytic efficiency of TiO2 under ultraviolet light irradiation, especially in promoting hydrogen generation and formaldehyde formation.

[0070] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments. It should be noted that many modifications and improvements can be made by those skilled in the art, and all modifications or improvements not exceeding the scope of the claims should be considered within the protection scope of the present invention.

Claims

1. An Ag 27 nanocluster photosensitizer characterized in that, The Ag 27 The chemical formula of the nanocluster photosensitizer is C 170 H 167 Ag 27 Cl2N 18 O6P7, consisting of 27 Ag atoms, 3 DPP organic ligands, 6 DPCA organic ligands, 2 DPPB organic ligands, 3 Ac ligands and 2 Cl, and is abbreviated as Ag 27 (DPCA)6(DPP)3(DPPB)2(Ac)3Cl2, belongs to monoclinic system; the space group is C2, α = 90°, β = 112.278 (7) °, γ = 90°, The molecular weight is 5758.39 Da; wherein the organic ligand DPCA is a deprotonated bis(2-pyridylmethyl)amine, the organic ligand DPP is a deprotonated diphenylphosphine hydrogen, the organic ligand DPPB is 1,4-bis(diphenylphosphino)butane, and the ligand Ac is CH3COO - The structural formulas of the organic ligands DPP, DPCA and DPPB are shown below, respectively:

2. The Ag of claim 1 27 Nanocluster photosensitizers characterized in that, The Ag 27 Two distorted Ag in nanocluster photosensitizer 13 Icosahedron fused by sharing triangular faces to form Ag 23 , and the remaining 4 Ag atoms are coordinated with Ag 23 Two Ag atoms in the core, P atoms in the diphenylphosphine ligand, and 2 N atoms in the bis (2-pyridylmethyl) amine ligand form 4 μ5-Ag sites, Ag 23 Together with 4 μ5-Ag to form the core of the cluster Ag 27 .

3. An Ag according to claim 1 or 2 27 A method for preparing a nanocluster photosensitizer, characterized by, It comprises the following steps: S1, dissolving silver salt in mixed solvent of dichloromethane and methanol, adding monophosphine ligand and bisphosphine ligand, stirring, then adding nitrogen ligand and acetic acid, continuing to stir fully, adding sodium borohydride aqueous solution, stirring fully under dark room temperature, obtaining green clear solution; the monophosphine ligand is diphenylphosphine hydrogen; the bisphosphine ligand is 1,4-bis(diphenylphosphino)butane; the nitrogen ligand is bis(2-pyridylmethyl)amine; S2, vapor diffusion of diethyl ether into the green clear solution as a diffusing agent, to obtain crystals, collect the crystal product, wash with diethyl ether and dry in vacuo to obtain Ag 27 Nanocluster photosensitizers.

4. The Ag of claim 3 27 A method for preparing a nanocluster photosensitizer, characterized by, The molar mass ratio of silver salt, monophosphine ligand, bisphosphine ligand, nitrogen ligand, acetic acid and sodium borohydride contained in sodium borohydride aqueous solution is 1:(0.6-1.3):(1.1-1.7):(0.4-1):(2-4):(12-20).

5. The Ag of claim 3 27 A method for preparing a nanocluster photosensitizer, characterized by, In step S1, the mixed solvent of dichloromethane and methanol is mixed by volume ratio of (4-5):1 of dichloromethane and methanol.

6. The Ag of claim 3 27 A method for preparing a nanocluster photosensitizer, characterized by, In step S1, the solubility concentration of silver salt in mixed solvent of dichloromethane and methanol is 0.009-0.012 mmol / ml.

7. The Ag of claim 3 27 A method for preparing a nanocluster photosensitizer, characterized by, The silver salt is silver trifluoromethane sulfonate.

8. An Ag as claimed in claim 1 or 2 27 Application of nanocluster photosensitizer in photocatalytic hydrogen production from water.

9. The Ag of claim 8 27 The application of nanocluster photosensitizer in photocatalytic hydrogen production from water, characterized in that, Ag 27 The nanocluster photosensitizer was loaded on TiO2 and applied to photocatalytic hydrogen production from water.

10. The Ag of claim 9 27 The application of nanocluster photosensitizer in photocatalytic hydrogen production from water, characterized in that, Ag 27 The loading of the nanocluster photosensitizer on TiO2 was 1%.

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