A sulfur-indium-zinc-based monatomic catalyst, a preparation method and application thereof

Abstract

This invention belongs to the field of photocatalytic materials technology, specifically relating to a zinc sulfide-based single-atom catalyst, its preparation method, and its application. The preparation method of the zinc sulfide-based single-atom catalyst includes the following steps: dissolving zinc salt, indium salt, and thioacetamide in an aqueous glycerol solution and carrying out a hydrothermal reaction to obtain zinc sulfide nanosheets; dispersing the zinc sulfide nanosheets in a mixed solution of water and methanol, adding a metal salt solution dropwise, and irradiating with light to obtain the zinc sulfide-based single-atom catalyst. The zinc sulfide-based single-atom catalyst of this invention can effectively separate photogenerated carriers and is also beneficial for the adsorption and activation of oxygen, generating more reactive oxygen species, thereby effectively improving the conversion rate of HMF and the selectivity of the target product DFF.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic materials technology, specifically relating to an indium sulfide zinc-based single-atom catalyst, its preparation method, and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention.

[0003] As an alternative to traditional fossil resources, the search for renewable energy from abundant lignocellulosic biomass has recently received particular attention. Among the most promising sources is 5-hydroxymethylfurfural (HMF), which can be obtained by dehydration of C6 carbohydrates and has a structure consisting of an aldehyde group, a hydroxyl group, and a furan ring. Furthermore, various high-value intermediates, such as 2,5-dicarboxyfuran (DFF), 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), 5-methyl-2-furancarboxylic acid (FFCA), and 2,5-furancarboxylic acid (FDCA), can be obtained through the selective oxidation of HMF molecules and are used in furan-based polyesters, pharmaceutical intermediates, and antibacterial agents. The selective oxidation of HMF has been extensively studied in thermocatalysis, electrocatalysis, and photocatalysis. Unlike thermochemical and electrochemical pathways that require direct or indirect energy consumption, photocatalysis, driven by sunlight under mild reaction conditions, has attracted widespread attention due to its advantages such as high solar energy utilization, tunable redox capacity, and simple operation.

[0004] However, due to the low electron-hole utilization rate of existing photocatalytic materials, it is difficult to generate a large number of active oxygen species to react with substrate intermediates, which limits the feed conversion rate and product selectivity of photocatalytic HMF oxidation. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide an indium sulfide-zinc-based single-atom catalyst, its preparation method, and its applications. The indium sulfide-zinc-based supported single atoms of this invention can effectively separate photogenerated carriers and simultaneously facilitate the adsorption and activation of oxygen, generating more reactive oxygen species. This effectively improves the conversion rate of HMF and the selectivity of the target product DFF.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing an indium sulfide zinc-based single-atom catalyst, comprising the following steps:

[0008] S1. Dissolve zinc salt, indium salt and thioacetamide in an aqueous glycerol solution and carry out a hydrothermal reaction to obtain zinc indium thiosulfate nanosheets;

[0009] S2. Disperse indium zinc sulfide nanosheets in a mixed solution of water and methanol, add metal salt solution dropwise, and obtain the indium zinc sulfide-based single-atom catalyst after light irradiation.

[0010] Preferably, the zinc salt includes at least one of zinc chloride, zinc nitrate, and zinc acetate, and the indium salt includes at least one of indium chloride, indium bromide, and indium nitrate.

[0011] Preferably, the molar ratio of the zinc salt, indium salt and thioacetamide is 1:1.9-2.1:3.9-4.1.

[0012] Preferably, the hydrothermal reaction temperature is 70-80℃ and the time is 1.5-2.5h.

[0013] Preferably, the metal salt is a soluble salt of a transition metal or a noble metal.

[0014] More preferably, the metal salt includes at least one of cobalt nitrate, ferric nitrate, nickel nitrate, potassium chloroplatinate, and ruthenium trichloride.

[0015] Preferably, the ratio of the metal salt to indium zinc sulfide nanosheets is 30-176 μmol: 1 g. The concentration of the metal salt solution needs to be sufficiently low to ensure metal dispersion and avoid agglomeration.

[0016] Preferably, a 300W xenon lamp with λ≥420nm is used for illumination, and the illumination time is 20-40 minutes, while maintaining the solution temperature below 10°C during illumination. When preparing single-atom catalysts using photodeposition, atomic aggregation can easily occur, resulting in clusters or nanoparticles. However, the presence of clusters or nanoparticles can be effectively avoided at lower temperatures.

[0017] In a second aspect, the present invention provides a zinc sulfide-indium-zinc-based single-atom catalyst, characterized in that it is obtained by the preparation method described in the first aspect.

[0018] The introduction of single atoms improves the photogenerated carrier capacity of indium zinc sulfide. At the same time, single atoms are electron-rich centers that can effectively promote the adsorption and activation of oxygen, thereby generating more reactive oxygen species and thus improving the conversion rate of HMF and the yield of product DFF.

[0019] Thirdly, the present invention provides the application of the zinc sulfide-indium-zinc-based single-atom catalyst as described in the second aspect in the photocatalytic value-added conversion of biomass resources.

[0020] Preferably, the photocatalytic biomass resource enhancement is converted into photocatalytic HMF oxidation.

[0021] The beneficial effects achieved by one or more technical solutions of the present invention are as follows:

[0022] Single-atom catalysts can effectively separate photogenerated carriers and facilitate the adsorption and activation of oxygen, generating more reactive oxygen species. This effectively improves the conversion rate of HMF and the selectivity of the target product DFF. Furthermore, the prepared single-atom catalysts can efficiently convert other biomass resources such as benzyl alcohol, furfuryl alcohol, and 2-thiophene benzyl alcohol, and can achieve high selectivity for products containing aldehyde groups.

[0023] This invention prepares a Co1 / ZIS single-atom catalyst on pristine ZIS ultrathin nanosheets via a simple low-temperature photodeposition method, achieving high conversion rates of HMF and the target product DFF under a green catalyst air atmosphere. Within 12 hours, the HMF conversion rate was 98.6%, and the DFF selectivity was 92.4%. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0025] Figure 1 HAADF-STEM images of Co1 / ZIS, Fe1 / ZIS, Pt1 / ZIS, Ni1 / ZIS, and Ru1 / ZIS;

[0026] Figure 2 XAFS structural characterization of Co1 / ZIS is shown in (a) normalized Co k-edge XANES spectrum, (b) linear fitting of absorption edge position in XANES curve, (c) FT-EXAFS spectra of Co1 / ZIS and Co foil, CoO and Co3O4 references, and (d) EXAFS fitting curve of Co1 / ZIS in R space.

[0027] Figure 3 (a) Comparison of DFF yields of ZIS and Co1 / ZIS selectively oxidizing HMF in air for 12 h; (b) Comparison of conversion and DFF selectivity of TiO2, Co1 / TiO2 and Co1 / ZIS selectively oxidizing HMF in air; (c) Photooxidation of HMF on ZIS samples loaded with different metal sites for DFF yield and selectivity.

[0028] Figure 4 The conversion rates of ZIS and Co1 / ZIS samples in selective oxidation of HMF in air and O2;

[0029] Figure 5Cyclic experiments of HMF oxidation by Co1 / ZIS in (a) without MnO2 and (b) with MnO2, and UV-Vis absorption spectra of the oxidation product H2O2, (c) standard curve and (d) spectra at different concentrations;

[0030] Figure 6 For HMF through O2 - and 1 Schematic diagram of DFF product produced by selective aerobic oxidation of Co1 / ZIS via O2 pathway. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0032] Example 1

[0033] ZnCl2 (1 mmol), InCl3·4H2O (2 mmol), and thioacetamide (8.0 mmol) were dissolved in an aqueous glycerol solution (80 mL, 20 vol%, pH = 2.5) and stirred. The mixture was then transferred to a water bath and reacted at 75 °C for 2 h. After cooling to room temperature, the product was collected by centrifugation, washed several times with deionized water and ethanol, and then vacuum dried overnight at 60 °C. The resulting zinc indium sulfide nanosheets were designated as ZIS.

[0034] Add 50 mg ZIS to a mixture of 30 mL water and methanol (v:v = 1:1) and disperse by sonication. Take 22 μL of 0.1 M cobalt nitrate aqueous solution and add it to 3 mL water. Slowly add this mixture dropwise to the ZIS suspension. After stirring for 30 min, irradiate with a 300 W xenon lamp (λ≥420 nm) for half an hour. During the irradiation, maintain the temperature of the reaction solution below 10 °C. Collect the sample by centrifugation and dry it. The obtained zinc sulfide-based single-atom catalyst is denoted as Co1 / ZIS.

[0035] Example 2

[0036] Unlike Example 1, the cobalt nitrate aqueous solution was replaced with an equal volume and concentration of iron nitrate aqueous solution, and the resulting indium sulfide zinc-based single-atom catalyst was denoted as Fe1 / ZIS.

[0037] Example 3

[0038] Unlike Example 1, the cobalt nitrate aqueous solution was replaced with an equal volume and concentration of nickel nitrate aqueous solution, and the resulting indium sulfide zinc-based single-atom catalyst was denoted as Ni1 / ZIS.

[0039] Example 4

[0040] Unlike Example 1, the cobalt nitrate aqueous solution was replaced with an equal volume and concentration of potassium chloroplatinate aqueous solution, and the resulting indium sulfide zinc-based single-atom catalyst was designated Pt1 / ZIS.

[0041] Example 5

[0042] Unlike Example 1, the cobalt nitrate aqueous solution was replaced with an equal volume and concentration of ruthenium trichloride aqueous solution, and the resulting indium sulfide zinc-based single-atom catalyst was denoted as Ru1 / ZIS.

[0043] Example 6

[0044] Unlike Example 1, 15 μL of a 0.1 M cobalt nitrate aqueous solution was added to 3 mL of water and mixed. The resulting indium sulfide zinc-based single-atom catalyst was denoted as Co1 / ZIS-0.15.

[0045] Example 7

[0046] Unlike Example 1, 44 μL of a 0.1 M cobalt nitrate aqueous solution was added to 3 mL of water and mixed. The resulting indium sulfide zinc-based single-atom catalyst was denoted as Co1 / ZIS-0.5.

[0047] Example 8

[0048] Unlike Example 1, 88 μL of a 0.1 M cobalt nitrate aqueous solution was added to 3 mL of water and mixed. The resulting indium sulfide zinc-based single-atom catalyst was designated Co1 / ZIS-1.

[0049] Comparative Example 1

[0050] ZnCl2 (1 mmol), InCl3·4H2O (2 mmol), and thioacetamide (8.0 mmol) were dissolved in an aqueous glycerol solution (80 mL, 20 vol%, pH = 2.5) and stirred. The mixture was then transferred to a water bath and reacted at 75 °C for 2 h. After cooling to room temperature, the product was collected by centrifugation, washed several times with deionized water and ethanol, and then vacuum dried overnight at 60 °C. The resulting zinc indium sulfide nanosheets were designated as ZIS.

[0051] Comparative Example 2

[0052] 50 mg of commercial titanium dioxide was added to a mixture of 30 mL of water and methanol (v:v = 1:1) and ultrasonically dispersed. 22 μL of 0.1 M cobalt nitrate aqueous solution was added to 3 mL of water and mixed. This mixture was then slowly added dropwise to the titanium dioxide suspension. After stirring for 30 min, the mixture was irradiated for half an hour with a 300 W xenon lamp (λ ≥ 420 nm). During the irradiation, the temperature of the reaction solution was maintained below 10 °C. The sample was collected by centrifugation and dried. The obtained single-atom catalyst was designated Co1 / TiO2.

[0053] Photocatalytic HMF aerobic oxidation performance test:

[0054] In a typical photocatalytic experiment, a reaction solution of HMF (5 mM), catalyst (15 mg), and acetonitrile (15 mL) was placed in a 50 mL quartz reactor, which was maintained at 25 °C throughout the process. A 300 W xenon lamp equipped with a 400 nm cutoff filter was used as the visible light source. The reaction solution was analyzed by high-performance liquid chromatography (HPLC) to obtain information on the HMF oxidation products.

[0055] like Figure 1 As shown, because the atomic numbers of Co, Fe, and Ni are lower than those of Zn and In, it is difficult to clearly separate isolated Co, Fe, and Ni atoms from Z1 / Z1. However, no aggregated Co, Fe, and Ni clusters or nanoparticles are found in Co1 / Z1, Fe1 / Z1, and Ni1 / Z1. Meanwhile, because the atomic numbers of Pt and Ru are higher than those of Zn and In species, it is possible to... Figure 1 The bright spots of atomic dispersion are clearly visible (circled area), and no Pt- and Ru-based clusters or nanoparticles were observed. Figure 1 This demonstrates the successful preparation of the zinc sulfide-indium-zinc-based single-atom catalyst of the present invention.

[0056] X-ray absorbing near-edge structures (XANES) of Co1 / ZIS, such as Figure 2 As shown, Co in Co1 / ZIS is close to +2 valence, no Co-Co or Co-O-Co bonds were observed, and Co is coordinated with O, indicating that the Co species exist in Co1 / ZIS in an atomically dispersed form.

[0057] like Figure 3 As shown in a, the photocatalytic HMF oxidation capacity of Co1 / ZIS is significantly improved compared to ZIS. This is attributed to the fact that cobalt single atoms can effectively separate photogenerated carriers and facilitate the adsorption and activation of oxygen, thereby generating more reactive oxygen species. Figure 3 As shown in b, Co1 / TiO2 has a high conversion rate for HMF, but low selectivity for the target product DFF. This is mainly due to its strong oxidizing power causing over-oxidation, which mineralizes the HMF. Figure 3 As shown in c, Co1 / ZIS, Fe1 / ZIS, Ni1 / ZIS, Pt1 / ZIS and Ru1 / ZIS have improved HMF photocatalytic oxidation ability compared to ZIS, and have excellent DFF selectivity for HMF conversion. Among them, Co1 / ZIS has the highest HMF conversion (98.6%) and DFF selectivity (92.4%).

[0058] like Figure 4As shown, the HMF conversion rate of Co1 / ZIS in air is higher than that in oxygen. Most current photocatalytic HMF oxidation studies use oxygen as the oxidant, while Co1 / ZIS can achieve a high HMF conversion rate in air, a green oxidant, which is beneficial to the development of green chemistry.

[0059] like Figure 5 As shown in (a), the stability of Co1 / ZIS decreases after three cycles, mainly because the hydroxyl radicals generated from the decomposition of the byproduct H2O2 oxidize the Zn-S chemical bonds of the ZIS catalyst to Zn-O bonds. Figure 5 As shown in (b), the addition of MnO2 decomposes the generated H2O2, inhibiting the oxidation of Zn-S bonds and significantly improving cycle stability. Figure 5 The standard curve (c) and spectral data (d) show that the concentration of H2O2 without MnO2 is 3.69 mM, which is greater than the concentration of H2O2 with MnO2, which is 2.29 mM.

[0060] Figure 6 The photocatalytic aerobic oxidation process of HMF using Co1 / ZIS was demonstrated. Two pathways dominated the process. Under illumination, photogenerated electrons accumulated on Co single atoms, while photogenerated holes accumulated on the ZnS layer. In the superoxide radical-mediated pathway, oxygen was first reduced to superoxide radicals by photogenerated electrons accumulated on Co single atoms. These superoxide radicals oxidized and deprotonated HMF to form an alcohol-oxygen anion intermediate. This intermediate was further oxidized by photogenerated holes to alcohol-oxygen anion radicals, which were ultimately attacked by hydrogen peroxide radicals to become the target product DFF, while generating hydrogen peroxide as a byproduct. In the singlet oxygen-dominated pathway, superoxide radicals could be oxidized to singlet oxygen by photogenerated holes. The singlet oxygen directly oxidized HMF to alcohol-oxygen anion radicals, ultimately yielding DFF.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. The application of an indium sulfide-zinc-based single-atom catalyst in photocatalytic HMF oxidation, wherein the preparation method of the indium sulfide-zinc-based single-atom catalyst includes the following steps: S1. Dissolve zinc salt, indium salt and thioacetamide in an aqueous glycerol solution and carry out a hydrothermal reaction to obtain zinc indium thiosulfate nanosheets; S2. Disperse indium zinc sulfide nanosheets in a mixed solution of water and methanol, add metal salt solution dropwise, and obtain the indium zinc sulfide-based single-atom catalyst after light irradiation. The ratio of the metal salt to zinc indium sulfide nanosheets is 30-176 μmol: 1 g; The metal salt includes at least one of cobalt nitrate, ferric nitrate, nickel nitrate, potassium chloroplatinate, and ruthenium trichloride; The illumination was performed using a 300 W xenon lamp with a wavelength of λ ≥ 420 nm for 20-40 min, while maintaining the solution temperature below 10℃.

2. The application as described in claim 1, characterized in that, The zinc salt includes at least one of zinc chloride, zinc nitrate, and zinc acetate, and the indium salt includes at least one of indium chloride, indium bromide, and indium nitrate.

3. The application as described in claim 1, characterized in that, The molar ratio of the zinc salt, indium salt, and thioacetamide is 1:1.9-2.1:3.9-4.

1.

4. The application as described in claim 1, characterized in that, The hydrothermal reaction is carried out at a temperature of 70-80 ℃ for 1.5-2.5 h.

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