A noble metal single-atom doped metal oxide catalyst and a preparation method and application thereof

Abstract

The application discloses a noble metal single-atom doped metal oxide catalyst and a preparation method and application thereof. The noble metal single-atom doped metal oxide catalyst is prepared from a precursor a, an active metal b and an additive c as raw materials. The precursor is at least one of manganese nitrate, cobalt nitrate, iron nitrate, nickel nitrate, chromium nitrate and copper nitrate. The active metal is at least one of ruthenium trichloride, iridium trichloride, rhodium trichloride, silver nitrate, chloroauric acid, palladium chloride and platinum tetrachloride. The additive c is a polyhydric alcohol or an organic acid. The catalyst prepared by the method can effectively oxidize 5-hydroxymethylfurfural to prepare 2,5-furan dicarboxylic acid under the reaction of oxygen as an oxidant at 100-150 DEG C.

Description

Technical Field

[0001] This invention belongs to the field of natural fragrance technology, specifically relating to a noble metal single-atom doped metal oxide catalyst, its preparation method, and its application. Background Technology

[0002] The depletion of fossil fuels and global climate change have made the search for new renewable resources an urgent priority. Biomass energy, due to its widespread availability and renewability, is considered a potential alternative to fossil fuels. Currently, many studies indicate that biomass resources can be converted into biofuels and value-added chemicals. Among these, 2,5-furandicarboxylic acid (2,5-Furfural) is widely used due to its unique furan ring with added functional diacid groups. In the field of bio-based polymers, 2,5-Furfural has the potential to replace fossil-based terephthalic acid due to its structural similarity to terephthalic acid, and can be used as a monomer for the production of polyvinyl fluoride (PEF) plastics. PEF has significant advantages in oxygen content and oxygen separation rate, and is considered a promising raw material for polyester chemicals. Currently, the catalytic oxidation of the biomass-based platform molecule 5-hydroxymethylfurfural to prepare 2,5-furandicarboxylic acid is the main route for its synthesis. Most of these reactions are carried out on supported nanocatalysts. Single-atom catalysts, as a new type of catalyst, have a similar mechanism of action to traditional supported nanocatalysts. They have higher catalytic activity, selectivity, atomic utilization, and controllable active centers, making them a hot research direction in the field of catalysis in recent years.

[0003] Currently, the oxidation of 5-hydroxymethylfurfural is mainly achieved through supported bimetallic oxide catalysts. Liao et al. conducted a study on catalyst performance, comparing the reaction effects of Pd nanoparticle-supported MnO2 catalysts (PdNP-MnO2) and Pd atom-supported MnO2 catalysts (Pd-MnO2) in the oxidation of 5-hydroxymethylfurfural. Experimental results showed that the Pd-MnO2 catalyst achieved twice the yield of 2,5-furandicarboxylic acid compared to the PdNP-MnO2 catalyst. This means that under the same conditions, the latter catalyst has twice the catalytic efficiency of the former. This result indicates that the performance of the catalyst can be significantly affected by changing the distribution and morphology of the active components. The Pd-MnO2 catalyst can provide more active sites, thereby improving the yield of 2,5-furandicarboxylic acid. Therefore, developing single-atom catalysts is beneficial for solving problems such as low catalytic efficiency and low metal utilization. Summary of the Invention

[0004] The first objective of this invention is to provide a noble metal single-atom doped metal oxide catalyst; the second objective is to provide a method for preparing the noble metal single-atom doped metal oxide catalyst; and the third objective is to provide the application of the noble metal single-atom doped metal oxide catalyst.

[0005] The first objective of this invention is achieved as follows: the noble metal single-atom doped metal oxide catalyst is prepared from precursor a, active metal b, and auxiliary agent c as raw materials. The precursor is at least one of manganese nitrate, cobalt nitrate, iron nitrate, nickel nitrate, chromium nitrate, and copper nitrate; the active metal is at least one of ruthenium trichloride, iridium trichloride, rhodium trichloride, silver nitrate, chloroauric acid, palladium chloride, and platinum tetrachloride; and the auxiliary agent c is a polyol or organic acid.

[0006] The second objective of this invention is achieved by including pretreatment and calcination steps, specifically including: A. Pretreatment: Weigh the catalyst a, active metal b and additive c according to the formula ratio, mix and grind them thoroughly to obtain material a; B. Calcination: Material a is calcined to obtain the target material, a noble metal single-atom doped metal oxide catalyst.

[0007] The specific steps are as follows: At least one of the precursors manganese nitrate, cobalt nitrate, ferric nitrate, nickel nitrate, chromium nitrate, or copper nitrate (a), one of ruthenium trichloride, iridium trichloride, rhodium trichloride, silver nitrate, chloroauric acid, palladium chloride, or platinum tetrachloride (b), and a polyol or organic acid auxiliary (c) are placed in an agate mortar and ground thoroughly to obtain a homogeneous mixture. The resulting mixture is then calcined at 200-400 °C for 1-3 h to obtain a noble metal single-atom doped metal oxide catalyst, wherein the molar ratio of a to b is (95-99.9):(0.1-5), and the molar ratio of c to the sum of a+b is 0.1-0.3:1; the polyol or organic acid auxiliary (c) includes at least one of citric acid, ethylenediaminetetraacetic acid, malic acid, tartaric acid, sorbitol, vitamin C, or xylitol.

[0008] In a preferred embodiment of the present invention, the resulting mixture is calcined at 200-400 °C for 1-3 h.

[0009] In a preferred embodiment of the present invention, the polyol or organic acid auxiliaries include, but are not limited to, at least one of citric acid, ethylenediaminetetraacetic acid, malic acid, tartaric acid, sorbitol, vitamin C, or xylitol.

[0010] In a preferred embodiment of the invention, calcination is carried out in an air atmosphere.

[0011] The third objective of this invention is achieved by the application of the noble metal single-atom doped metal oxide catalyst in the catalytic oxidation of 5-hydroxymethylfurfural to prepare 2,5-furandicarboxylic acid.

[0012] The specific preparation steps are as follows: 5-Hydroxymethylfurfural, a base, and a solvent were mixed and placed in a reaction vessel. The aforementioned noble metal single-atom doped metal oxide catalyst was added, and the reaction was carried out using oxygen as the oxygen source. After the reaction was completed, the pH of the reaction solution was adjusted to acidic with concentrated hydrochloric acid to obtain 2,5-furandicarboxylic acid. The reaction temperature was 100-150 °C, the time was 0.5-3 h, the pressure was 1-20 bar, the concentration of 5-hydroxymethylfurfural in the solvent was 0.5-20 wt%, the mass ratio of catalyst to 5-hydroxymethylfurfural was 0.2-3:1, and the molar ratio of base to 5-hydroxymethylfurfural was 0.1-3:1.

[0013] In a preferred embodiment of the present invention, the reaction temperature is 100-150 °C, the time is 1-3 h, the pressure is 1-20 bar, the concentration of 5-hydroxymethylfurfural in the solvent is 0.5-20 wt%, the mass ratio of catalyst to 5-hydroxymethylfurfural is 0.5-2:1, and the molar ratio of base to 5-hydroxymethylfurfural is 0.5-2:1.

[0014] In a preferred embodiment of the present invention, the alkali used is one of sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, or potassium bicarbonate.

[0015] Compared with the prior art, this technical solution has the following advantages: 1. The catalyst prepared in this invention utilizes a low-doped amount of noble metal to prepare a single-atom catalyst, which effectively oxidizes 5-hydroxymethylfurfural to prepare 2,5-furandicarboxylic acid.

[0016] 2. This invention provides a solvent-free, simple, and easily scalable method for preparing metal oxides doped with a small amount of noble metal single atoms. The preparation process is solvent-free, simple, environmentally friendly, and easy to scale up. In this method, the desired metal oxide can be obtained through simple grinding and calcination. Furthermore, by selecting different metal molar ratios during the grinding process, the content of noble metal single atoms in the catalyst can be effectively changed, thereby greatly improving the catalytic oxidation activity of the catalyst.

[0017] This invention utilizes a solvent-free, simple, and easily scalable method to prepare noble metal single-atom-doped metal oxides as catalysts. The preparation process eliminates the need for solvents, acids, alkalis, and other expensive and polluting chemical reagents, making it an economical and environmentally friendly catalyst preparation process. The prepared single-atom-doped oxide catalyst exhibits high catalytic efficiency, effectively catalyzing the oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid under mild reaction conditions. Attached Figure Description

[0018] Figure 1 Aberration-corrected transmission electron microscopy (TEM) image of the catalyst; Among them, a-catalyst aberration-corrected high-angle annular dark-field scanning transmission electron microscope (TEM) image; b-catalyst aberration-corrected high-angle annular dark-field scanning TEM image; c-catalyst X-ray energy dispersive spectroscopy (EDS) analysis of Mn elemental spectrum; d-catalyst X-ray energy dispersive spectroscopy (EDS) analysis of Ru elemental spectrum. Figure 2 The synchrotron radiation spectrum of the catalyst; Among them, a- X-ray absorption near-edge structure of the Ru K-side catalyst; b- X-ray absorption fine structure spectrum of the Ru K-side catalyst. Detailed Implementation

[0019] The present invention will be further described below with reference to embodiments, but this is not intended to limit the present invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0020] The noble metal single-atom doped metal oxide catalyst of the present invention is prepared from precursor a, active metal b and auxiliary agent c as raw materials. The precursor is at least one of manganese nitrate, cobalt nitrate, iron nitrate, nickel nitrate, chromium nitrate and copper nitrate; the active metal is at least one of ruthenium trichloride, iridium trichloride, rhodium trichloride, silver nitrate, chloroauric acid, palladium chloride and platinum tetrachloride; and the auxiliary agent c is a polyol or organic acid.

[0021] The polyol mentioned is sorbitol or xylitol.

[0022] The organic acid mentioned is citric acid, ethylenediaminetetraacetic acid, malic acid, tartaric acid, or vitamin C.

[0023] The molar ratio of precursor a to active metal b is (95~99.9):(0.1~5); the molar ratio of auxiliary c to the sum of a+b is (0.1~0.3):1.

[0024] The method for preparing a noble metal single-atom doped metal oxide catalyst according to the present invention includes pretreatment and calcination steps, specifically including: A. Pretreatment: Weigh the catalyst a, active metal b and additive c according to the formula ratio, mix and grind them thoroughly to obtain material a; B. Calcination: Material a is calcined to obtain the target material, a noble metal single-atom doped metal oxide catalyst.

[0025] The calcination temperature in step B is 200~400℃, and the time is 1~3h.

[0026] The calcination described in step B is carried out in an air atmosphere.

[0027] The application of the noble metal single-atom doped metal oxide catalyst of the present invention is its application in the catalytic oxidation of 5-hydroxymethylfurfural to prepare 2,5-furandicarboxylic acid.

[0028] The catalytic oxidation of 5-hydroxymethylfurfural to prepare 2,5-furandicarboxylic acid includes pretreatment and main reaction steps, specifically including: A. Pretreatment: 5-hydroxymethylfurfural, alkali and deionized water are mixed and placed in a reaction vessel, and then the noble metal single-atom doped metal oxide catalyst is added; the alkali is sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate or potassium bicarbonate; B. Main reaction: Using oxygen as the oxygen source, react at a temperature of 100~150℃ and a pressure of 1~20 bar for 0.5~3h to obtain 2,5-furandicarboxylic acid.

[0029] In step A, the concentration of 5-hydroxymethylfurfural in the solvent is 0.5~20wt%; the mass ratio of noble metal single-atom doped metal oxide catalyst to 5-hydroxymethylfurfural is (0.2~3):1; and the molar ratio of alkali to 5-hydroxymethylfurfural is (0.1~3):1.

[0030] The invention will be further illustrated below with specific implementation examples: Example 1 Preparation of ruthenium single-atom-doped manganese oxide catalyst: Manganese nitrate a (9.99 mmol), ruthenium trichloride b (0.01 mmol), and auxiliary agent c (2 mmol) vitamin C were mixed and ground uniformly, wherein the molar ratio of a to b was 99.9 / 0.1, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the ruthenium single-atom-doped manganese oxide catalyst.

[0031] The oxidation process of 5-hydroxymethylfurfural: 0.03 g of 5-hydroxymethylfurfural, 0.04 g of sodium bicarbonate, and 3 g of water were added to a 10 mL autoclave, followed by 0.03 g of the aforementioned ruthenium-doped manganese oxide as a catalyst. After sealing the autoclave, oxygen was introduced to pressurize to 10 bar, and then the mixture was heated to 130 °C with vigorous stirring (600 rpm) and maintained for 1.5 hours to terminate the reaction. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 1.

[0032] Example 2 Preparation of ruthenium single-atom-doped manganese oxide catalyst: Manganese nitrate a (9.95 mmol), ruthenium trichloride b (0.05 mmol), and auxiliary agent c (2 mmol) vitamin C were mixed and ground uniformly, wherein the molar ratio of a to b was 99.5 / 0.5, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the ruthenium single-atom-doped manganese oxide catalyst.

[0033] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 2.

[0034] Example 3 Preparation of ruthenium single-atom-doped manganese oxide catalyst: Manganese nitrate a (9.9 mmol), ruthenium trichloride b (0.1 mmol), and auxiliary agent c (2 mmol) vitamin C were mixed and ground uniformly, wherein the molar ratio of a to b was 99 / 1, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the ruthenium single-atom-doped manganese oxide catalyst.

[0035] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 3.

[0036] Example 4 Preparation of ruthenium single-atom-doped cobalt oxide catalyst: Cobalt nitrate a (9.95 mmol), ruthenium trichloride b (0.05 mmol), and auxiliary agent c (2 mmol) vitamin C were mixed and ground uniformly, wherein the molar ratio of a to b was 99.5 / 0.5, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the ruthenium single-atom-doped cobalt oxide catalyst.

[0037] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 4.

[0038] Example 5 Preparation of ruthenium single-atom-doped iron oxide catalyst: Ferric nitrate a (9.95 mmol), ruthenium trichloride b (0.05 mmol), and auxiliary agent c (2 mmol) vitamin C were mixed and ground uniformly, wherein the molar ratio of a to b was 99.5 / 0.5, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the ruthenium single-atom-doped iron oxide catalyst.

[0039] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 5.

[0040] Example 6 Preparation of ruthenium single-atom-doped nickel oxide catalyst: Nickel nitrate a (9.95 mmol), ruthenium trichloride b (0.05 mmol), and auxiliary agent c (2 mmol) vitamin C were mixed and ground uniformly, wherein the molar ratio of a to b was 99.5 / 0.5, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the ruthenium single-atom-doped nickel oxide catalyst.

[0041] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 6.

[0042] Example 7 Preparation of ruthenium single-atom-doped chromium oxide catalyst: Chromium nitrate a (9.95 mmol), ruthenium trichloride b (0.05 mmol), and auxiliary agent c (2 mmol) vitamin C were mixed and ground uniformly, wherein the molar ratio of a to b was 99.5 / 0.5, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the ruthenium single-atom-doped chromium oxide catalyst.

[0043] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 7.

[0044] Example 8 Preparation of ruthenium single-atom-doped copper oxide catalyst: Copper nitrate a (9.95 mmol), ruthenium trichloride b (0.05 mmol), and auxiliary agent c (2 mmol) vitamin C were mixed and ground uniformly, wherein the molar ratio of a to b was 99.5 / 0.5, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the ruthenium single-atom-doped copper oxide catalyst.

[0045] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 8.

[0046] Example 9 Preparation of iridium-doped manganese oxide catalyst: Manganese nitrate a (9.95 mmol), iridium trichloride b (0.05 mmol), and auxiliary agent c (2 mmol) vitamin C were mixed and ground uniformly, wherein the molar ratio of a to b was 99.5 / 0.5, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the iridium-doped manganese oxide catalyst.

[0047] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 9.

[0048] Example 10 Preparation of rhodium-doped manganese oxide catalyst: Manganese nitrate a (9.95 mmol), rhodium trichloride b (0.05 mmol), and auxiliary agent c (2 mmol) vitamin C were mixed and ground uniformly, wherein the molar ratio of a to b was 99.5 / 0.5, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain rhodium-doped manganese oxide catalyst.

[0049] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 10.

[0050] Example 11 Preparation of silver-doped manganese oxide catalyst: Manganese nitrate a (9.95 mmol), silver nitrate b (0.05 mmol), and auxiliary agent c (2 mmol) vitamin C were mixed and ground evenly, with the molar ratio of a to b being 99.5 / 0.5 and the molar ratio of c to the sum of a and b being 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the silver-doped manganese oxide catalyst.

[0051] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 11.

[0052] Example 12 Preparation of gold-doped manganese oxide catalyst: Manganese nitrate a (9.95 mmol), chloroauric acid b (0.05 mmol), and auxiliary agent c (2 mmol) vitamin C were mixed and ground uniformly, wherein the molar ratio of a to b was 99.5 / 0.5, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the gold-doped manganese oxide catalyst.

[0053] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 12.

[0054] Example 13 Preparation of palladium single-atom-doped manganese oxide catalyst: Manganese nitrate a (9.95 mmol), palladium chloride b (0.05 mmol), and auxiliary agent c (2 mmol) vitamin C were mixed and ground uniformly, wherein the molar ratio of a to b was 99.5 / 0.5, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain palladium single-atom-doped manganese oxide catalyst.

[0055] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 13.

[0056] Example 14 Preparation of platinum single-atom-doped manganese oxide catalyst: Manganese nitrate a (9.95 mmol), platinum tetrachloride b (0.05 mmol), and auxiliary agent c (2 mmol) vitamin C were mixed and ground uniformly, wherein the molar ratio of a to b was 99.5 / 0.5, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain platinum single-atom-doped manganese oxide catalyst.

[0057] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 14.

[0058] Example 15 Preparation of ruthenium single-atom-doped manganese oxide catalyst: Manganese nitrate a (9.95 mmol), ruthenium trichloride b (0.05 mmol), and citric acid c (2 mmol) were mixed and ground uniformly, with the molar ratio of a to b being 99.5 / 0.5 and the molar ratio of c to the sum of a and b being 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the ruthenium single-atom-doped manganese oxide catalyst.

[0059] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 15.

[0060] Example 16 Preparation of ruthenium single-atom-doped manganese oxide catalyst: Manganese nitrate a (9.95 mmol), ruthenium trichloride b (0.05 mmol), and ethylenediaminetetraacetic acid c (2 mmol) were mixed and ground uniformly, wherein the molar ratio of a to b was 99.5 / 0.5, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the ruthenium single-atom-doped manganese oxide catalyst.

[0061] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 16.

[0062] Example 17 Preparation of ruthenium single-atom-doped manganese oxide catalyst: Manganese nitrate a (9.95 mmol), ruthenium trichloride b (0.05 mmol), and auxiliary agent c (2 mmol) malic acid were mixed and ground uniformly, wherein the molar ratio of a to b was 99.5 / 0.5, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the ruthenium single-atom-doped manganese oxide catalyst.

[0063] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 17.

[0064] Example 18 Preparation of ruthenium single-atom-doped manganese oxide catalyst: Manganese nitrate a (9.95 mmol), ruthenium trichloride b (0.05 mmol), and tartaric acid c (2 mmol) were mixed and ground uniformly, with the molar ratio of a to b being 99.5 / 0.5 and the molar ratio of c to the sum of a and b being 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the ruthenium single-atom-doped manganese oxide catalyst.

[0065] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 18.

[0066] Example 19 Preparation of ruthenium single-atom-doped manganese oxide catalyst: Manganese nitrate a (9.95 mmol), ruthenium trichloride b (0.05 mmol), and sorbitol c (2 mmol) were mixed and ground uniformly, wherein the molar ratio of a to b was 99.5 / 0.5, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the ruthenium single-atom-doped manganese oxide catalyst.

[0067] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 19.

[0068] Example 20 Preparation of ruthenium single-atom-doped manganese oxide catalyst: Manganese nitrate a (9.95 mmol), ruthenium trichloride b (0.05 mmol), and xylitol c (2 mmol) were mixed and ground uniformly, wherein the molar ratio of a to b was 99.5 / 0.5, and the molar ratio of c to the sum of a and b was 0.2. The resulting mixture was calcined at 350 °C for 2 hours in air to obtain the ruthenium single-atom-doped manganese oxide catalyst.

[0069] The oxidation process of 5-hydroxymethylfurfural was the same as in Example 1, except that the catalyst in Example 1 was replaced with this catalyst. Qualitative and quantitative analysis was performed using HPLC (Water 2487), and the results are listed in Table 1, numbered 20.

[0070] Examples 21-23 Add 0.03 g of 5-hydroxymethylfurfural, 3 g of water, and 0.04 g of sodium bicarbonate to a 10 mL autoclave, then add 0.03 g of ruthenium single-atom doped manganese oxide prepared in Example 2 as a catalyst. Seal the autoclave, introduce oxygen at 5 bar, 15 bar, or 20 bar, stir vigorously (600 rpm), heat to 130 °C and maintain for 1.5 hours, stop the reaction, cool to room temperature, and take samples. Perform qualitative and quantitative detection using HPLC (Water 2487). The detection results are listed in Table 1, serial numbers 21-23.

[0071] Examples 24-26 Add 0.15 g, 0.3 g, or 0.6 g of 5-hydroxymethylfurfural, 3 g of water, and 0.04 g, 0.19 g, 0.4 g, or 0.8 g of sodium bicarbonate to a 10 mL autoclave. Then add 0.15 g, 0.3 g, or 0.6 g of ruthenium-doped manganese oxide (0.15 g, 0.3 g, or 0.6 g) prepared in Example 2 as a catalyst. Seal the autoclave, introduce 10 bar of oxygen, stir vigorously (600 rpm), heat to 130 °C and maintain for 1.5 hours. After the reaction is completed, cool to room temperature and take samples. Perform qualitative and quantitative detection using HPLC (Water 2487). The detection results are listed in Table 1, serial numbers 27-29.

[0072] Table 1 shows the detection results in each embodiment. .

Claims

1. A noble metal single-atom doped metal oxide catalyst, characterized in that, The noble metal single-atom doped metal oxide catalyst is prepared from precursor a, active metal b, and auxiliary agent c. The precursor is at least one of manganese nitrate, cobalt nitrate, iron nitrate, nickel nitrate, chromium nitrate, and copper nitrate; the active metal is at least one of ruthenium trichloride, iridium trichloride, rhodium trichloride, silver nitrate, chloroauric acid, palladium chloride, and platinum tetrachloride; and the auxiliary agent c is a polyol or organic acid. The preparation method of the noble metal single-atom doped metal oxide catalyst specifically includes: A. Pretreatment: Weigh the catalyst a, active metal b and additive c according to the formula ratio, mix and grind them thoroughly to obtain material a; B. Calcination: Material a is calcined to obtain the target material, a noble metal single-atom doped metal oxide catalyst.

2. The noble metal single-atom doped metal oxide catalyst according to claim 1, characterized in that, The polyol mentioned is sorbitol or xylitol.

3. The noble metal single-atom doped metal oxide catalyst according to claim 1, characterized in that, The organic acid mentioned is citric acid, ethylenediaminetetraacetic acid, malic acid, tartaric acid, or vitamin C.

4. The noble metal single-atom doped metal oxide catalyst according to claim 1, characterized in that, The molar ratio of precursor a to active metal b is (95~99.9):(0.1~5); the molar ratio of auxiliary c to the sum of a+b is (0.1~0.3):

1.

5. A method for preparing a noble metal single-atom doped metal oxide catalyst according to any one of claims 1 to 4, characterized in that... This includes pretreatment and calcination steps, specifically: A. Pretreatment: Weigh the catalyst a, active metal b and additive c according to the formula ratio, mix and grind them thoroughly to obtain material a; B. Calcination: Material a is calcined to obtain the target material, a noble metal single-atom doped metal oxide catalyst.

6. The preparation method according to claim 5, characterized in that, The calcination temperature in step B is 200~400℃, and the time is 1~3h.

7. The preparation method according to claim 5, characterized in that, The calcination described in step B is carried out in an air atmosphere.

8. The application of a noble metal single-atom doped metal oxide catalyst according to any one of claims 1 to 4, characterized in that, The application of the noble metal single-atom doped metal oxide catalyst in the catalytic oxidation of 5-hydroxymethylfurfural to prepare 2,5-furandicarboxylic acid.

9. The application according to claim 8, characterized in that, The catalytic oxidation of 5-hydroxymethylfurfural to prepare 2,5-furandicarboxylic acid includes pretreatment and main reaction steps, specifically including: A. Pretreatment: 5-hydroxymethylfurfural, alkali and deionized water are mixed and placed in a reaction vessel, and then the noble metal single-atom doped metal oxide catalyst is added; the alkali is sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate or potassium bicarbonate; B. Main reaction: Using oxygen as the oxygen source, react at a temperature of 100~150℃ and a pressure of 1~20 bar for 0.5~3h to obtain 2,5-furandicarboxylic acid.

10. The application according to claim 9, characterized in that, In step A, the concentration of 5-hydroxymethylfurfural in the solvent is 0.5~20wt%; the mass ratio of noble metal single-atom doped metal oxide catalyst to 5-hydroxymethylfurfural is (0.2~3):1; and the molar ratio of alkali to 5-hydroxymethylfurfural is (0.1~3):1.

Images