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CN-122011021-A - Gold nanocluster and preparation method thereof, catalyst and preparation method and application thereof

CN122011021ACN 122011021 ACN122011021 ACN 122011021ACN-122011021-A

Abstract

The application relates to the technical field of nano material synthesis and catalysis, in particular to a gold nanocluster, a preparation method thereof, a catalyst, a preparation method thereof and application thereof. The gold nanocluster has a molecular formula of Au 40 (TBBT) 24 (TPMP), wherein TBBT is 4-tert-butylthiophenol, and TPMP is tri-m-phenylphosphine. The catalyst has precise atomic number and definite molecular structure, the synergistic effect of the mixed ligand (mercaptan and phosphine) on the surface of the gold atomic nucleus further regulates and controls the electronic structure and the surface property of the cluster, and optimizes the adsorption and activation capability of substrate molecules, so that the catalytic efficiency and stability can be improved, and particularly for reduction reactions such as reduction of 4-nitrophenol, the cluster can realize high-efficiency catalytic conversion under mild conditions.

Inventors

  • HUANG BAOYU
  • ZHAO XIAOMEI
  • FANG ZHENGJUN

Assignees

  • 湖南工程学院

Dates

Publication Date
20260512
Application Date
20260409

Claims (10)

  1. 1. A gold nanocluster is characterized by having a molecular formula of Au 40 (TBBT) 24 (TPMP), wherein TBBT is 4-tert-butylphenol and TPMP is tri-m-phenylphosphine.
  2. 2. The method for preparing gold nanoclusters according to claim 1, comprising the steps of: S1, mixing a gold source and a phase transfer agent in a first organic solvent to form a first gold complex solution; s2, adding a first ligand and a second ligand into the first gold complex solution, stirring and mixing to form a second gold complex solution, wherein the first ligand is tri-m-phenylphosphine, and the second ligand is 4-tert-butylthiophenol; s3, adding a reducing agent into the second gold complex solution to perform a first reduction reaction to obtain a reaction solution containing a crude product; S4, removing the solvent, and washing to obtain a crude product; S5, dissolving the crude product in a second organic solvent, adding the first ligand and the second ligand, heating and stirring to perform curing treatment; s6, separating and purifying the cured product to obtain the gold nanocluster.
  3. 3. The preparation method of claim 2, wherein in the step S1, the gold source is chloroauric acid or chloroauric acid salt, the Jin Yuanyi Jin Yuanshui solution is added, and the concentration of the gold source in the Jin Yuanshui solution is 0.1-0.3 mg/mL; The phase transfer agent is selected from tetra-n-octyl ammonium bromide; The first organic solvent is a mixed solvent comprising dichloromethane and methanol; The second organic solvent is selected from toluene; The reducing agent is sodium borohydride or potassium borohydride, and is added in the form of aqueous solution.
  4. 4. The method according to claim 2, wherein the molar ratio of the gold source to the phase transfer agent is 1:1-3; in the step S2, the molar ratio of the added first ligand to the gold source is 0.2-0.3:1; In the step S2, the molar ratio of the added second ligand to the gold source is 3-5:1; In the step S3, the mol ratio of the reducing agent to the gold source is 6.5-8.2:1; In the step S5, the molar ratio of the added first ligand, second ligand and gold source is 0.06-0.085:2.5-3:1.
  5. 5. The preparation method according to claim 2, wherein in step S1, after the gold source and the phase transfer agent are mixed in the first organic solvent, stirring is continued for 3-5 min under the condition of a stirring rate of 1500-160 rmp; in the step S2, stirring and mixing are carried out for 3-5 min; In the step S5, the curing treatment is carried out at the temperature of 50-60 ℃ for 20-25 hours under the condition of the stirring rate of 200-300 rmp; In step S6, the separation and purification adopts thin layer chromatography, and the developing agent is a mixed solvent of dichloromethane and n-hexane.
  6. 6. The catalyst is characterized by comprising a carrier and an active component loaded on the carrier, wherein the active component comprises the gold nanocluster according to claim 1 or the gold nanocluster obtained by the preparation method according to any one of claims 2-5, and the carrier is selected from any one or more of activated carbon, carbon nanotubes, graphene and silicon dioxide.
  7. 7. The catalyst of claim 6, wherein the loading of the active component in the catalyst is 5wt% to 10wt%.
  8. 8. The method for preparing the catalyst according to any one of claims 6 to 7, characterized by comprising the steps of: mixing and stirring the active component and the carrier in a third organic solvent to load the active component on the carrier, and then sequentially carrying out centrifugal separation and drying to obtain the catalyst.
  9. 9. The use of the catalyst according to any one of claims 6 to 7 or the catalyst obtained by the preparation method according to claim 8 for catalyzing reduction of 4-nitrophenol to prepare 4-aminophenol, characterized by comprising the steps of: mixing the catalyst, 4-nitrophenol, sodium borohydride and water, and carrying out reduction reaction at normal temperature.
  10. 10. The use according to claim 9, wherein the mass ratio of the catalyst, the 4-nitrophenol and the sodium borohydride is 15-17:1:2.8-3.4.

Description

Gold nanocluster and preparation method thereof, catalyst and preparation method and application thereof Technical Field The application relates to the technical field of nano material synthesis and catalysis, in particular to a gold nanocluster, a preparation method thereof, a catalyst, a preparation method thereof and application thereof. Background The application of the atomic-scale precise metal nanocluster in the catalysis field marks the heterogeneous catalysis field to realize the breakthrough transition from the nano-age to the atomic-age. The conversion realizes high customization of catalytic activity and selectivity through accurate regulation and control of atomic-level active sites, and provides great potential for developing new-generation high-efficiency, excellent-selectivity, economical and practical industrial catalysts. The combination of these nanoclusters with a carrier is a key strategy, and its effect is not only to fix the clusters by physicochemical interactions, prevent migration and sintering, ensure high dispersibility and stability, but also to form novel high active sites at the interface. This innovation will shift the reaction mechanism from "single active site" to "complex active site". The reduction reaction of 4-nitrophenol is one of important organic synthesis reactions, and the product 4-aminophenol is widely applied to the preparation of medicines, dyes, rubber and polymer monomers, is a key basic raw material in the fields of fine chemical engineering and material science, and has great market demands. At present, the synthesis of 4-aminophenol mainly depends on a metal oxide catalyst (such as zinc oxide and aluminum oxide) or adopts high-temperature and high-pressure conditions, and the problems of harsh reaction conditions, easy influence of the catalyst on product selectivity, multiple byproducts and the like exist. Therefore, the development of the catalyst capable of realizing high-efficiency catalysis under mild conditions can obviously improve the production efficiency and reduce the production cost. The existing metal nanocluster still has the defect of lower catalytic efficiency when being used as an active component for catalyzing 4-nitrophenol to prepare 4-aminophenol, and based on the defect, the catalyst capable of further improving the efficiency of catalyzing 4-nitrophenol to prepare 4-aminophenol is needed to be provided. Disclosure of Invention Based on the above, the application aims to overcome the defects of the prior art and provides a gold nanocluster, a preparation method thereof, a catalyst, a preparation method thereof and application thereof. Solves the problems of harsh reaction conditions and low catalytic efficiency when the traditional catalyst catalyzes the reduction reaction of 4-nitrophenol to produce 4-aminophenol. In order to achieve the above purpose, the application adopts the following technical scheme: firstly, the application provides a gold nanocluster, which has a molecular formula of Au 40(TBBT)24 (TPMP), wherein TBBT is 4-tert-butylphenol and TPMP is tri-m-phenylphosphine. Based on a general inventive concept, the application also provides a preparation method of the gold nanocluster, comprising the following steps: S1, mixing a gold source and a phase transfer agent in a first organic solvent to form a first gold complex solution; s2, adding a first ligand and a second ligand into the first gold complex solution, stirring and mixing to form a second gold complex solution, wherein the first ligand is tri-m-phenylphosphine, and the second ligand is 4-tert-butylthiophenol; S3, adding a reducing agent into the second gold complex solution for reduction reaction to obtain a reaction solution containing a crude product; S4, removing the solvent, and washing to obtain a crude product; S5, dissolving the crude product in a second organic solvent, adding the first ligand and the second ligand, heating and stirring to perform curing treatment; s6, separating and purifying the cured product to obtain the gold nanocluster. Preferably, in the step S1, the gold source is chloroauric acid or chloroauric acid salt, the Jin Yuanyi Jin Yuanshui solution is added, and the concentration of the gold source in the Jin Yuanshui solution is 0.1-0.3 mg/mL. Preferably, the phase transfer agent is selected from tetra-n-octylammonium bromide. Preferably, the first organic solvent is a mixed solvent including dichloromethane and methanol. Preferably, the second organic solvent is selected from toluene. Preferably, the reducing agent is sodium borohydride or potassium borohydride, and the reducing agent is added in the form of an aqueous solution. Preferably, the molar ratio of the gold source to the phase transfer agent is 1:1-3, and more preferably, the molar ratio of the gold source to the phase transfer agent is 1:1.5-2. Preferably, in step S2, the molar ratio of the first ligand to the gold source is 0.2-0.3:1. More preferably, the molar ratio of t