Carbon-doped modified carrier and preparation method and application thereof, oxidation catalyst and preparation method and application thereof, and method for synthesizing hydrogen peroxide from hydrogen and oxygen

Abstract

The invention relates to a carbon-doped modified carrier and a preparation method and application thereof, an oxidation catalyst and a preparation method and application thereof, and a method for synthesizing hydrogen peroxide from hydrogen and oxygen, and discloses a carbon-doped modified carrier and a preparation method and application thereof. The carbon-doped modified carrier contains a carrier base material and a C element for carrying out carbon-doped modification on the carrier base material, the content of the C element is 0.1-30wt% based on the total weight of the carbon-doped modified carrier, and the Raman spectrum is characterized in that ID / IG is 0.5-1, and the water contact angle range is 10-120 degrees. The carbon-doped modified carrier is especially suitable for being used as a carrier of a catalyst, and is especially suitable for being used as a carrier of a catalyst for directly synthesizing hydrogen peroxide from hydrogen and oxygen.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, specifically to a carbon-doped modified support and its preparation method and application, an oxidation catalyst and its preparation method and application, and a method for synthesizing hydrogen peroxide from hydrogen and oxygen. Background Technology

[0002] Based on the reaction mechanism of H2 and O2 ( Figure 1 The competition between the formation of H2O2 (Ⅰ) and its subsequent decomposition (Ⅲ) and hydrogenation (Ⅳ) in a series largely determines the selectivity of the final product. Furthermore, the byproduct water also accumulates in the reaction system, leading to a decrease in the concentration of hydrogen peroxide solution after the reaction, increasing the cost of enrichment and concentration. Considering that this reaction involves three phases (gas, liquid, and solid), assuming that the generated H2O2 can be rapidly transferred from the catalyst, the series of side reactions will be suppressed due to the low H2O2 concentration on the catalytic surface.

[0003]

[0004] CN113856680A relates to a magnetic carbon-doped spinel copper ferrite catalyst, its preparation method and application. The carbon-containing stock solution in this technology is obtained by hydrothermal reaction of L-ascorbic acid, ethylene glycol and water.

[0005] The paper *Catalysts*, 2017, 7(6): 175, uses dichloromethane as a carbon precursor to synthesize a series of carbon-doped Pd-based catalysts for the direct synthesis of H2O2. The reaction results show that the hydrogenation side reaction is significantly suppressed on the modified catalyst, exhibiting higher H2O2 selectivity and yield. However, this method is complex, and the raw materials involve toxic substances such as phenylphosphonic acid and dichloromethane, which is detrimental to safe production. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of existing technologies, such as the easy occurrence of tandem side reactions of H2O2 on the catalyst surface and low selectivity and yield of H2O2. This invention provides a modified support, its preparation method, and its applications. This modified support is particularly suitable as a catalyst support, especially as a support for the direct synthesis of hydrogen peroxide from hydrogen and oxygen. This catalyst has the advantages of effectively suppressing side reactions and improving the selectivity and yield of the direct synthesis of H2O2.

[0007] According to a first aspect of the present invention, a carbon-doped modified support is provided, the carbon-doped modified support comprising a support base and carbon-doped C element of the support base, wherein the C element content is 0.1-30 wt% based on the total weight of the carbon-doped modified support, and the Raman spectral characteristics include: I D / I GThe range is 0.5-1, and the water contact angle ranges from 10-120°.

[0008] According to a second aspect of the present invention, the present invention provides a method for preparing the carbon-doped modified support of the present invention, the method comprising: contacting and impregnating a carbon precursor solution with a support base, followed by drying and calcination.

[0009] According to a third aspect of the present invention, the present invention provides the application of the carbon-doped modified support of the present invention in the use of oxidation catalyst support, degradation of organic pollutants in water, and preparation of conductive functional materials.

[0010] According to a fourth aspect of the present invention, an oxidation catalyst is provided, comprising: a carbon-doped modified support as described in the present invention, an oxidation active component, and optionally an oxidation aid component; preferably, the oxidation active component is Pd; and / or the oxidation aid component is selected from one or more of Au, Pt, Ag, Te, Ni, Co, Sn, Ce, W, Fe, Cu, and Zn, preferably Au and / or Pt; and / or the content of the carbon-doped modified support is 90-99.9 wt%, preferably 95-99.5 wt%, based on the total weight of the catalyst; and / or the content of the oxidation active component is 0.1-5 wt%, preferably 0.5-3 wt%; and / or the content of the oxidation aid component is 0-5 wt%, preferably 0.5-2 wt%.

[0011] According to a fifth aspect of the present invention, the present invention provides a method for preparing the oxidation catalyst of the present invention, wherein the method comprises:

[0012] (1) The carbon-doped modified carrier is prepared according to the preparation method of the carbon-doped modified carrier of the present invention;

[0013] (2) The precursor solution of the oxidizing active component source and optionally the oxidizing aid component source is impregnated with the carbon-doped modified support, and then dried and heat-treated to obtain the catalyst.

[0014] According to a sixth aspect of the present invention, the present invention provides an application of the oxidation catalyst provided by the present invention in the direct synthesis of hydrogen peroxide from hydrogen and oxygen.

[0015] According to a seventh aspect of the present invention, a method for synthesizing hydrogen peroxide from hydrogen and oxygen is provided, the method comprising: contacting H2 with O2 in the presence of the oxidation catalyst described herein. Preferably, the molar ratio of H2 to O2 is 1 / 5-1 / 2; preferably, the contact is carried out in the presence of a liquid solvent selected from water, methanol, or ethanol; preferably, the contact is carried out in the presence of nitrogen; the molar ratio of hydrogen to nitrogen is 1 / 2-3 / 4; and / or the contact conditions include: a reaction temperature of 5-20 K; and / or a reaction pressure of 1-5 atm; and / or a mixed gas flow rate of 30-120 mL·min. -1 Preferably 50-80 mL·min -1 .

[0016] The carbon-doped modified support of the present invention is particularly suitable as a support for catalysts, especially as a support for catalysts for the direct synthesis of hydrogen peroxide from hydrogen and oxygen. This catalyst has the advantages of effectively suppressing the occurrence of side reactions and improving the selectivity and yield of direct synthesis of H2O2. Attached Figure Description

[0017] Figure 1 The thermogravimetric analysis (TGA) diagrams of the catalyst samples from Examples 1-4 are shown.

[0018] Figure 2 This is a HADDF-STEM image of the modified carrier.

[0019] Figure 3-7 Water contact angle diagrams for the modified carriers 1-4 used in Examples 1-4, corresponding to TiO2 (Comparative Example 1).

[0020] Figure 8 The Raman spectra of the modified supports 1-4 used in Examples 1-4 are shown for TiO2 (Comparative Example 1). Detailed Implementation

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] This invention provides a carbon-doped modified support, which contains a support base and carbon (C) element to modify the support base. The C element content, based on the total weight of the carbon-doped modified support, is 0.1-30 wt%. The Raman spectral characteristics include: I D / I GThe concentration is 0.5-1, and the water contact angle ranges from 10-120°. The carbon-doped modified support of the present invention is particularly suitable as a support for catalysts, especially as a support for catalysts for the direct synthesis of hydrogen peroxide from hydrogen and oxygen. This catalyst has the advantages of effectively suppressing the occurrence of side reactions and improving the selectivity and yield of direct H2O2 synthesis.

[0023] The modified support of this invention has carbon elements highly dispersed on the surface of the support base. For example, the HADDF-STEM image of the modified support of Example 3 of this invention is shown in the attached figure. Figure 2 As shown in the figure, carbon elements (red) are mainly coated on the surface of the TiO2 support.

[0024] In this invention, carbon element is highly dispersed on the surface of the support base, thereby making the modified support particularly suitable as a catalyst support, especially as a catalyst support for the direct synthesis of hydrogen peroxide from hydrogen and oxygen. This catalyst has the advantages of effectively suppressing the occurrence of side reactions and improving the selectivity and yield of the direct synthesis of H2O2.

[0025] According to one embodiment of the present invention, the carbon content is 3-20 wt%, more preferably 7-16 wt%, based on the total weight of the carbon-modified support. Therefore, the modified support is particularly suitable as a catalyst support, especially as a support for a catalyst used in the direct synthesis of hydrogen peroxide from hydrogen and oxygen, which has the advantages of effectively suppressing side reactions and improving the selectivity and yield of the direct synthesis of H2O2.

[0026] In this invention, there are no special requirements for the carrier base material. The following is an illustrative description, but it does not limit the scope of the invention. According to one embodiment of the invention, the carrier base material is selected from one or more of Al2O3, TiO2 and SiO2, preferably TiO2.

[0027] According to one embodiment of the present invention, the Raman spectral characteristics of the carbon-doped modified support include: I D / I G It is 0.7-0.8.

[0028] According to one embodiment of the present invention, the water contact angle ranges from 20 to 90°, preferably from 40 to 80°.

[0029] The carbon-doped modified support with the aforementioned characteristics is particularly suitable as a support for catalysts, especially as a support for catalysts for the direct synthesis of hydrogen peroxide from hydrogen and oxygen. This catalyst has the advantages of effectively suppressing the occurrence of side reactions and improving the selectivity and yield of direct synthesis of H2O2.

[0030] In this invention, there are no special requirements for the preparation method of the carbon-doped modified support. The following is an illustrative description, but it does not limit the scope of the invention. According to one embodiment of the invention, the invention provides a method for preparing a carbon-doped modified support, which includes: contacting and impregnating a carbon precursor solution with a support base, followed by drying and calcination.

[0031] In this invention, the concentration of carbon precursor in the carbon precursor solution can be selected within a wide range during the preparation of the carbon-modified support, but this does not limit the scope of the invention. According to a preferred embodiment of the invention, the concentration of carbon precursor in the carbon precursor solution is 0.1-5 g / mL, preferably 0.5-2 g / mL, for example 0.5 g / mL, 1 g / mL, 1.5 g / mL, or 2 g / mL.

[0032] In this invention, the range of carbon precursors that can be selected is relatively wide during the preparation of the carbon-modified support. According to a preferred embodiment of this invention, the carbon precursor is a soluble carbon source, preferably selected from carbohydrates, and more preferably selected from monosaccharides (C6H4O2). 12 O6) and disaccharide (C 12 H 22 O 11 One or more of the following.

[0033] According to a preferred embodiment of the present invention, preferably, the monosaccharide comprises glucose and / or fructose.

[0034] According to a preferred embodiment of the present invention, the disaccharide includes sucrose and / or lactose.

[0035] In existing carbon-doped synthesis methods, the carbon precursors commonly used are: (1) organic compounds, such as dichloromethane, but these carbon precursors are highly toxic and pose potential risks; (2) resins, but the average cost of these carbon precursors is higher than US$2,000 per ton, which is not conducive to cost control and makes industrialization difficult. The raw materials used in this method are relatively safe and inexpensive, the synthesis steps are simple, the application range is wide, and the amount of carbon doped can be controlled.

[0036] The modified support prepared using the aforementioned carbon precursor is particularly suitable as a catalyst support, especially as a catalyst support for the direct synthesis of hydrogen peroxide from hydrogen and oxygen. This catalyst has the advantages of effectively suppressing the occurrence of side reactions and improving the selectivity and yield of the direct synthesis of H2O2.

[0037] In the preparation process of the carbon-doped modified carrier, the impregnation conditions can be selected from a wide range. This is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the impregnation conditions include: an impregnation time of 10-14 hours, for example, 10 hours, 11 hours, 12 hours, or 14 hours.

[0038] In this invention, the impregnation can be carried out under static or dynamic conditions, depending on the specific needs.

[0039] In this invention, there are no special requirements for the liquid-to-solid phase ratio; it can be selected and determined according to needs. According to a preferred embodiment of this invention, the contact impregnation is performed using either an equal-volume impregnation method or an excess impregnation method. Specifically, in excess impregnation, rotary evaporation is required, and the total liquid volume generally does not exceed 2.5 mL / g solid.

[0040] In this invention, there are no special requirements for drying conditions during the preparation of the carbon-doped modified carrier. This is an illustrative example and does not limit the scope of the invention. According to a preferred embodiment of the invention, the drying conditions include: a drying temperature of 373-393K, for example, 373K, 378K, 383K, or 393K. There are no special requirements for the drying time, which can be determined based on the drying conditions, etc. Generally, the drying time is 12-24 hours, for example, 12 hours, 15 hours, 18 hours, or 24 hours.

[0041] In this invention, after drying and before calcination, grinding can be performed as needed.

[0042] In this invention, the calcination conditions can be selected from a wide range during the preparation of the carbon-doped modified carrier. This is an illustrative example, but does not limit the scope of the invention. According to a preferred embodiment of the invention, the calcination conditions include a calcination temperature of 673-873K, for example, 673K, 723K, 773K, or 873K.

[0043] In this invention, there are no special requirements for the calcination equipment; for example, the calcination can be carried out in a tube furnace.

[0044] In this invention, the calcination time can be selected from a wide range, and the specific time is determined according to the calcination temperature. It is generally 1-3 hours, for example, 1 hour, 2 hours, 2.5 hours, or 3 hours.

[0045] In this invention, calcination is preferably carried out in an inert atmosphere; preferably, the inert atmosphere is a nitrogen atmosphere and / or an argon atmosphere.

[0046] In this invention, during calcination, the preferred gas flow rate is 30-60 mL / min.

[0047] The carbon-doped modified support provided by this invention is particularly suitable for use as an oxidation catalyst support, in the degradation of organic pollutants in water, and in the preparation of conductive functional materials.

[0048] The present invention provides a catalyst comprising: a carbon-doped modified support provided by the present invention or a modified support prepared by the method for preparing the modified support provided by the present invention, an oxidation-active component, and optionally an oxidation aid component.

[0049] In this invention, the range of oxidizing active components is relatively wide. Commonly used oxidizing active components can be applied to this invention. This is an illustrative example, but it does not limit the scope of this invention. Preferably, the oxidizing active component is Pd.

[0050] In this invention, the range of oxidizing agent components is relatively wide, and commonly used oxidizing agent components can all be applied to this invention. This is an illustrative example, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the oxidizing agent component is selected from one of Au, Pt, Ag, Te, Ni, Co, Sn, Ce, W, Fe, Cu, and Zn, preferably Au and / or Pt.

[0051] In this invention, the content of each component in the oxidation catalyst can be selected within a wide range. Commonly used content ranges can be applied to this invention. This is an illustrative example, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the content of the carbon-modified support is 90-99.9 wt% based on the total weight of the catalyst, preferably 95-99.5 wt%.

[0052] In this invention, the content of each component in the oxidation catalyst can be selected within a wide range. Commonly used content ranges can be applied to this invention. This is an illustrative example, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the content of the oxidation active component is 0.1-5 wt% based on the total weight of the catalyst, preferably 0.5-3 wt%.

[0053] In this invention, the content of each component in the oxidation catalyst can be selected within a wide range. Commonly used content ranges can be applied to this invention. This is an illustrative example, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the content of the oxidation aid component is 0-5 wt% based on the total weight of the catalyst, preferably 0.5-2 wt%.

[0054] In this invention, as long as the objective of this invention can be achieved, there are no special requirements for the preparation method of the oxidation catalyst provided by this invention. According to a preferred embodiment of this invention, the preparation method includes:

[0055] (1) The carbon-doped modified carrier is prepared according to the preparation method of the carbon-doped modified carrier of the present invention;

[0056] (2) The precursor solution of the oxidizing active component source and optionally the oxidizing aid component source is impregnated with the carbon-doped modified support, and then dried and heat-treated to obtain the catalyst.

[0057] The preparation method of the modified carrier in this invention has been described in detail above and will not be repeated here.

[0058] In this invention, there are no special requirements for the impregnation conditions during the preparation of the oxidation catalyst. This is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the impregnation conditions include an impregnation time of 4-12 hours.

[0059] In this invention, there are no special requirements for drying conditions during the preparation of the oxidation catalyst. This is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the drying conditions include a drying temperature of 333-433K, preferably 373-393K, for example 353K, 373K, 383K, or 393K.

[0060] In this invention, there are no special requirements for drying conditions during the preparation of the oxidation catalyst. This is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the drying time can be selected from a wide range, for example, 12-24 h, such as 12h, 15h, 18h, 24h, preferably 12-16h.

[0061] In this invention, there are no special requirements for heat treatment conditions during the preparation of the oxidation catalyst. This is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the heat treatment is divided into two stages: the first stage is calcination in air, and the second stage is reduction in a hydrogen-containing atmosphere.

[0062] In this invention, the range of selectable calcination conditions in the first stage is relatively wide. This is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the calcination temperature is 573-773K, for example, 573K, 673K, 723K, or 773K.

[0063] In this invention, the calcination time in the first stage can be selected from a wide range, and is specifically determined based on the calcination temperature. This is an illustrative example, but does not limit the scope of the invention. According to a preferred embodiment of the invention, the calcination time is 1-4 hours, for example, 1 hour, 2 hours, 2.5 hours, or 4 hours.

[0064] In this invention, the conditions for the reduction in the second stage in a hydrogen-containing atmosphere are available in a wide range. This is an illustrative example, but does not limit the scope of the invention. According to a preferred embodiment of the invention, the reduction temperature in the second stage is 473-673K, for example, 473K, 523K, 573K, or 673K.

[0065] In this invention, the reduction time in the second stage can be selected within a wide range, and is specifically determined based on the reduction temperature. This is an illustrative example, but does not limit the scope of the invention. According to a preferred embodiment of the invention, the reduction time is 1-4 hours, for example, 1 hour, 1.5 hours, 2 hours, or 4 hours.

[0066] In this invention, the hydrogen-containing atmosphere is preferably a mixture of H2 and an inert gas, preferably with a hydrogen content of 30-60% by volume, and preferably with nitrogen gas.

[0067] The oxidation catalyst provided by this invention is particularly suitable for use as a catalyst in the direct synthesis of hydrogen peroxide from hydrogen and oxygen. It has the advantages of effectively suppressing the occurrence of side reactions and improving the selectivity and yield of direct H2O2 synthesis.

[0068] This invention provides the application of the oxidation catalyst of this invention in the direct synthesis of hydrogen peroxide from hydrogen and oxygen; preferably, the application steps include: contacting H2 and O2 in the presence of the oxidation catalyst of this invention.

[0069] In this invention, the molar ratio of H2 to O2 can be selected within a wide range, for example, 1 / 5 to 1 / 2.

[0070] In this invention, the contact is preferably carried out in the presence of a liquid solvent, which is selected from one or more of water, methanol, and acidified ethanol, for example, a small amount of sulfuric acid acidified ethanol.

[0071] In this invention, the amount of liquid solvent can be selected from a wide range. For example, the mass ratio of liquid solvent to catalyst can be 1-10 mL / mg for testing.

[0072] In this invention, preferably, the contact is carried out in the presence of nitrogen; the molar ratio of hydrogen to nitrogen is 1 / 2-3 / 4.

[0073] In this invention, as long as the purpose of this invention can be achieved, there are no special requirements for the reaction conditions for the synthesis of hydrogen peroxide from hydrogen and oxygen. This is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the reaction conditions include: a reaction temperature of 278-303K, for example, 278K, 283K, 288K, or 303K.

[0074] In this invention, the range of selectable reaction pressures is relatively wide. This is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the reaction pressure is 1-5 atm, for example, 1 atm, 1.2 atm, 1.5 atm, or 3 atm.

[0075] In this invention, the range of selectable reaction gas rates is relatively wide, which is illustrative but does not limit the scope of the invention. According to a preferred embodiment of the invention, the mixed gas flow rate is 30-120 mL·min. -1 Preferably 50-80 mL·min -1 For example, 40 mL·min -1 60 mL·min -1 80 mL·min -1 100 mL·min -1 .

[0076] In this invention, during the preparation of the support or catalyst, in order to make the solid-liquid impregnation as complete as possible, the liquid can be added dropwise to the solid for contact, and stirring can be used during the contact process to make the impregnation as complete and thorough as possible. As needed, room temperature aging can be carried out, and the room temperature aging time can generally be 1-24 hours. The aging process is stirred irregularly as needed, for example, every 0.5-1 hour.

[0077] In this invention, during the specific implementation process, the solution is added drop by drop to the solid using a pipette and continuously stirred until it is uniformly mixed. Then, it is aged at room temperature with stirring every 0.5-1 hour. This is only an exemplary test method of this invention and should not be used to limit the scope of this invention.

[0078] In this invention, during the preparation of the support or catalyst, grinding can be performed as needed after drying and before calcination.

[0079] The present invention will be described in detail below through embodiments. In the following embodiments,

[0080] In this invention, the main raw materials are the substances listed in Table 1 below. Substances not shown are all commercially available industrial-grade reagents.

[0081] Table 1

[0082] name Molecular formula purity Manufacturer Palladium chloride <![CDATA[PdCl4]]> ≥99.9％ Sigma-Aldrich Tetrachloroauric acid trihydrate <![CDATA[HAuCl4·3H2O]]> ≥99.9％ Adamas-beta Titanium dioxide <![CDATA[TiO2(P25)]]> ≥99.5％ Evonik Industries Fumed silica <![CDATA[SiO2]]> ≥99.5％ Evonik Industries Activated alumina <![CDATA[Al2O3]]> >90.0％ Titan Technology Co., Ltd. glucose <![CDATA[C6H 12 O6]]> ≥99.5％ Sigma-Aldrich 30% hydrogen peroxide <![CDATA[H2O2]]> ≥30.0％ Shanghai Lingfeng Chemical Reagent Co., Ltd. ammonium sulfate <![CDATA[(NH4)2SO4]]> ≥99.0％ Shanghai Lingfeng Chemical Reagent Co., Ltd. Titanium sulfate oxysulfate-sulfuric acid hydrate <![CDATA[TiOSO4·xH2SO4·xH2O]]> ≥93.0％ Aladdin Biochemical Technology Co., Ltd. sulfuric acid <![CDATA[H2SO4]]> ≥96.0％ Sinopharm Chemical Reagent Co., Ltd. hydrochloric acid HCl 36-38％ General-reagent Anhydrous ethanol <![CDATA[C2H5OH]]> ≥99.7％ General-reagent Deionized water <![CDATA[H2O]]> Homemade (18.25Ω) Nanjing Yipu Yida Technology Development Co., Ltd.

[0083] The formula for calculating the carbon content in the carbon-modified carrier is as follows: thermogravimetric analysis, TG / % difference at 573-773K.

[0084] H2 conversion test method: Using N2 as an internal standard, a standard curve for H2 conversion is pre-plotted. The H2 / N2 area ratio collected chromatographically during the experiment is substituted into the standard curve to obtain the H2 conversion rate. The formula for calculating the H2O2 yield is as follows:

[0085]

[0086] The Raman characteristic testing method includes: acquiring laser Raman spectra using a Horiba LabRAM HR 800 confocal Raman spectrometer. For visible light at 514.5 nm or 633 nm, argon ions (Ar) are used for measurement. + Excitation was performed using a HeCd laser in 325nm ultraviolet light. The spectrum was collected through a 50× / 20× long-focal-length Leica objective lens and detected on the backscattered plane using a CCD array detector (1024×256 pixels). The grating was 1800 grids / mm, with a resolution of 1–4 cm⁻¹. -1 .

[0087] The water contact angle was tested using a Dataphysics OCA20 contact angle meter, which measured the water contact angle of different C-TiO2 supports. Before the test, approximately 100 mg of support powder was finely ground and compressed into tablets. The test solvent was a 10 wt.% H2O2 solution.

[0088] Figure 1 The thermogravimetric analysis (TGA) curves of the catalyst samples in Examples 1-4 show that each sample exhibits varying degrees of weight loss within the temperature range of 300-500°C. This difference directly represents the actual carbon content in the support.

[0089] Figure 2 The image shows the HADDF-STEM image of the modified support. Carbon elements (red) are mainly coated on the surface of the TiO2 support, and the thickness of the carbon layer varies depending on the amount of carbon doping.

[0090] Figure 3-7 The diagrams show the water contact angles of the modified supports 1-4 used in Examples 1-4, corresponding to TiO2 (Comparative Example 1). The results indicate that the unmodified TiO2 has strong hydrophilicity, while the water contact angle significantly increases after interfacial modulation, confirming that the modified C-TiO2 support exhibits significantly enhanced hydrophobicity.

[0091] Figure 8 Raman spectra of modified supports 1-4 used in Examples 1-4, corresponding to TiO2 (Comparative Example 1). Modified supports 1-4 correspond to Examples 1-4, and TiO2 corresponds to Comparative Example 1. The raw material TiO2 was used in samples with a wavelength <800 cm⁻¹. -1 Three consecutive peaks were observed at a depth of approximately 1350 cm⁻¹, the intensity of which decreased until it disappeared with increasing carbon content covering the surface. -1 and ~1590cm -1 At these locations, the D and G peaks, corresponding to amorphous carbon and graphitized carbon, gradually increase in intensity, respectively.

[0092] Example 1

[0093] [Preparation of carbon-doped modified supports]

[0094] 1. Weigh 2g of TiO2 into a 50mL beaker and prepare a 1g / mL glucose solution;

[0095] 2. Using a pipette, take 0.5 mL of glucose solution and 1.5 mL of deionized water respectively, and add them dropwise to the TiO2 carrier, stirring constantly with a glass rod until they are mixed evenly;

[0096] 3. Let the well-mixed mud-like substance stand at room temperature for 12 hours, stirring once every 1 hour;

[0097] 4. Place the beaker in an oven and dry it at 383K for 12 hours;

[0098] 5. After drying, the support is taken out, ground, and placed in a tube furnace. It is calcined at 773 K for 2 hours in an Ar atmosphere with a flow rate of 40 mL / min, and then allowed to cool naturally to room temperature to obtain the modified support.

[0099] The carbon doping amount, Raman characteristics, and water contact angle of the carbon-modified carrier are shown in Table 2.

[0100] [Preparation of Oxidation Catalysts]

[0101] 1. Place 1.94 g of carbon-modified carrier in a 50 mL beaker;

[0102] 2. Using a pipette, pipette 0.8 mL of 0.05 g / mL (concentration calculated as Pd) H2PdCl4 and 0.4 mL of 0.05 g / mL (concentration calculated as Au) HAuCl4 solution and place them in a 10 mL beaker and mix well.

[0103] 3. Transfer the above mixed solution dropwise to a beaker containing the carrier, stirring with a glass rod while adding the solution;

[0104] 4. Continue to add 0.4 mL of deionized water to the above beaker, and stir continuously with a glass rod until the mixture is homogeneous;

[0105] 5. Let the well-mixed slurry stand at room temperature for 6 hours, stirring once every hour.

[0106] 6. Place the beaker in an oven and dry it at 383K for 12 hours;

[0107] 7. Take out the dried catalyst, grind it, calcine it in air at 673 K for 2 hours, and reduce it in 50% H2 / N2 at 573 K for 2 hours to obtain the catalyst (specific composition: total content of Pd and Au is 3wt%, Pd / Au ratio is 2:1).

[0108] Example 2

[0109] The method is the same as in Example 1, except that in step 2 of the preparation of the carbon-modified support, 1.0 mL of glucose solution and 1.0 mL of deionized water are taken.

[0110] The carbon doping amount, Raman characteristics, and water contact angle of the carbon-modified carrier are shown in Table 2.

[0111] Example 3

[0112] The method is the same as in Example 1, except that in step 2 of the preparation of the carbon-modified carrier, 1.5 mL of glucose solution and 0.5 mL of deionized water are taken.

[0113] The carbon doping amount, Raman characteristics, and water contact angle of the carbon-modified carrier are shown in Table 2.

[0114] Example 4

[0115] The method is the same as in Example 1, except that in step 2 of the preparation of the carbon-modified carrier, 2.0 mL of glucose solution and 0.0 mL of deionized water are taken.

[0116] The carbon doping amount, Raman characteristics, and water contact angle of the carbon-modified carrier are shown in Table 1.

[0117] Example 5

[0118] The method is the same as in Example 1, except that gaseous SiO2 is used instead of TiO2.

[0119] The carbon doping amount, Raman characteristics, and water contact angle of the carbon-modified carrier are shown in Table 2.

[0120] Example 6

[0121] The method is the same as in Example 1, except that in step 1 of the preparation of the carbon-modified carrier, a 1 g / mL disaccharide (sucrose: lactose = 1:1) solution is used.

[0122] The carbon doping amount, Raman characteristics, and water contact angle of the carbon-modified carrier are shown in Table 2.

[0123] Example 7

[0124] The method is the same as in Example 1, except that in step 1 of the preparation of the carbon-modified support, a 0.1 g / mL glucose solution is used.

[0125] The carbon doping amount, Raman characteristics, and water contact angle of the carbon-modified carrier are shown in Table 2.

[0126] Example 8

[0127] The method is the same as in Example 1, except that in step 2 of the preparation of the oxidation catalyst, 0.4 mL of 0.05 g / mL (concentration calculated as Pd) H2PdCl4 and 0.8 mL of 0.05 g / mL (concentration calculated as Au) HAuCl4 solution are taken (specific composition: total content of Pd and Au is 3 wt%, Pd / Au is 1:2).

[0128] Example 9

[0129] The method is the same as in Example 1, except that in step 7 of the preparation of the oxidation catalyst, the catalyst is not reduced in hydrogen.

[0130] Comparative Example 1

[0131] The comparative catalyst was prepared according to the method of Example 1, except that unmodified TiO2 was used as the support.

[0132] Comparative Example 2

[0133] The C09 catalyst from CN113117671A is used.

[0134] Chemical evaluation test:

[0135] Hydrogen and oxygen can be directly synthesized into hydrogen peroxide.

[0136] The catalyst performance evaluation test was conducted at 1 atm and 283 K, with a total gas flow rate into the reactor of 60 mL / min. -1 (H2 / O2 / N2 = 15 / 60 / 25), acidified anhydrous ethanol as solvent (60 mL ethanol + 0.38 mL H2SO4), catalyst dosage of 50 mg, reaction carried out at a stirring rate of 1000 rpm.

[0137] In this experiment, the reaction solution was taken out from the reactor at different times, mixed with the colorimetric reagent, and then sent to UV Vis to analyze its absorbance and test the H2O2 content. The results are shown in Table 2.

[0138] Table 2

[0139]

[0140]

[0141] As can be seen from the results in Table 1, the preferred embodiments of the present invention have the advantages of effectively suppressing the occurrence of side reactions and improving the selectivity and yield of direct synthesis of H2O2.

[0142] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A carbon-modified carrier, characterized in that, The carbon-doped modified support contains a support base and carbon (C) elements that modify the support base with carbon. The C content, based on the total weight of the carbon-doped modified support, is 0.1-30 wt%. Raman spectral characteristics include: I D / I G The range is 0.5-1, and the water contact angle ranges from 10-120°.

2. The carbon-doped modified carrier according to claim 1, wherein, The carbon content is 3-20 wt%, more preferably 7-16 wt%, based on the total weight of the carbon-modified carrier; and / or The support base is selected from one or more of Al2O3, TiO2, and SiO2, preferably TiO2; and / or Raman spectral characteristics include: I D / I G 0.7-0.8; and / or The water contact angle ranges from 20 to 90°, preferably from 40 to 80°.

3. The method for preparing the carbon-doped modified support according to claim 1 or 2, characterized in that, The method includes: contacting and impregnating a carbon precursor solution with a carrier base, followed by drying and calcination.

4. The preparation method according to claim 3, wherein, The concentration of carbon precursor in the carbon precursor solution is 0.1-5 g / mL, preferably 0.5-2 g / mL; The carbon precursor is a soluble carbon source, preferably selected from carbohydrates, and more preferably from monosaccharides (C6H4O2). 12 O6) and disaccharide (C 12 H 22 O 11 One or more of the following; Preferably, the monosaccharide includes glucose and / or fructose, and the disaccharide includes sucrose and / or lactose; and / or The conditions for impregnation include: an impregnation time of 10-14 hours; and / or performing the contact impregnation under dynamic conditions; and / or performing the contact impregnation using an equal-volume impregnation method or an over-impregnation method. and / or The drying conditions include a temperature of 373-393 K and / or a time of 12-24 h; and / or The calcination conditions include: a temperature of 673-873 K; and / or a time of 1-3 h; and / or calcination is carried out in an inert atmosphere; preferably, the inert atmosphere is a nitrogen atmosphere and / or an argon atmosphere; and / or a gas flow rate of 30-60 mL / min.

5. The application of the carbon-doped modified support as described in claim 1 or 2 in the application of the support for oxidation catalysts, degradation of organic pollutants in water, and preparation of conductive functional materials.

6. An oxidation catalyst, characterized in that, The oxidation catalyst comprises: the carbon-modified support as described in claim 1 or 2, the oxidation active component, and optionally the oxidation aid component; Preferably, The oxidizing active component is Pd; and / or The oxidizing agent component is selected from one or more of Au, Pt, Ag, Te, Ni, Co, Sn, Ce, W, Fe, Cu, and Zn, preferably Au and / or Pt; and / or The content of the carbon-modified support, based on the total weight of the catalyst, is 90-99.9 wt%, preferably 95-99.5 wt%; and / or the content of the oxidation active component is 0.1-5 wt%, preferably 0.5-3 wt%; and / or the content of the co-active component is 0-5 wt%, preferably 0.5-2 wt%.

7. A method for preparing an oxidation catalyst, characterized in that, The method includes: (1) A carbon-modified support is prepared according to the method of any one of claims 3-4; (2) The precursor solution of the oxidizing active component source and optionally the oxidizing aid component source is impregnated with the carbon-doped modified support, and then dried and heat-treated to obtain the catalyst.

8. The preparation method according to claim 7, wherein, The immersion conditions include: an immersion time of 4-12 hours, preferably 8-10 hours; and / or The drying conditions include: a drying temperature of 333-433K, preferably 373-393K; a drying time of 12-24h, preferably 12-16h; and / or The heat treatment consists of two stages: the first stage is calcination in air, and the second stage is reduction in a hydrogen-containing atmosphere. The first stage calcination temperature is 573-773K, and the calcination time is 1-4h; the second stage reduction temperature is 473-673K, and the reduction time is 1-4h; and / or The hydrogen-containing atmosphere is a mixture of H2 and an inert gas, preferably with a hydrogen content of 30-60% by volume, and preferably, the inert gas is nitrogen.

9. The application of the oxidation catalyst according to claim 6 or the oxidation catalyst prepared by the preparation method according to claim 7 or 8 in the direct synthesis of hydrogen peroxide from hydrogen and oxygen.

10. A method for synthesizing hydrogen peroxide from hydrogen and oxygen, characterized in that, In the presence of the oxidation catalyst according to claim 6 or the catalyst prepared by the preparation method according to claim 7 or 8, H2 comes into contact with O2; Preferably, the molar ratio of H2 to O2 is 1 / 5 to 1 / 2; Preferably, the contact is carried out in the presence of a liquid solvent, which is selected from one or more of water, methanol, and acidified ethanol. The mass ratio of liquid solvent to catalyst is 1-10 mL / mg; Preferably, the contact is carried out in the presence of nitrogen; The molar ratio of hydrogen to nitrogen is 1 / 2 to 3 / 4; and / or The conditions for H2 to contact with O2 include: The reaction temperature is 278-303 K; and / or the reaction pressure is 1-5 atm; and / or the mixed gas flow rate is 30-120 mL·min. -1 Preferably 50-80 mL·min -1 .

Images