A carbon-supported MoO x Preparation of a cluster catalyst and its application for the electro-synthesis of hydrogen peroxide

Abstract

The application belongs to the technical field of catalysts, and particularly relates to a carbon-loaded MoO x The application relates to preparation of a cluster catalyst and application of the cluster catalyst to electro-synthesis of hydrogen peroxide. The catalyst comprises an oxygen-doped carbon carrier and a MoO x cluster active component; the oxygen-doped carbon carrier is a two-dimensional nanosheet structure, and the MoO x cluster is a sub-nanometer cluster with a size of <2 nm. The application successfully prepares a sub-nanometer molybdenum oxide cluster composite material loaded on an oxygen-doped carbon carrier by combining pre-adsorption and low-temperature pyrolysis. The composite material utilizes the excellent conductivity and stable structure of the functionalized carbon carrier to provide stable anchoring sites for the sub-nanometer molybdenum oxide cluster with high surface energy, and through construction of a strong interface coupling, the catalytic activity, selectivity and long-term stability of the catalyst in the electro-synthesis of hydrogen peroxide are synergistically enhanced, thereby providing a new material design idea for development of a high-efficiency, stable and low-cost non-noble metal hydrogen peroxide synthesis catalyst.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalyst preparation technology, specifically relating to a carbon-supported MoO2. x Preparation of cluster catalysts and their application in the electrosynthesis of hydrogen peroxide. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Hydrogen peroxide (H2O2), as an important green chemical, is mainly produced industrially via the anthraquinone process. However, this method suffers from high energy consumption, complex processes, and environmental pollution. Furthermore, centralized, large-scale production carries safety risks and high costs associated with transportation and storage. Therefore, developing a low-carbon, distributed, on-site H2O2 synthesis technology is of great significance. Electrocatalytic two-electron oxygen reduction reaction (2e...) - ORR (Organic Oxygen Reduction), driven by renewable electricity, directly converts water and oxygen into H2O2 under mild conditions and is considered a promising green alternative. However, the widespread application of this technology is limited by the lack of efficient and low-cost electrocatalysts. Currently, noble metal catalysts such as platinum-mercury (PtHg) and palladium-mercury (PdHg) exhibit good performance, but their high cost and scarcity restrict the large-scale promotion of the technology. Therefore, developing abundant non-noble metal catalysts has become the key to overcoming this bottleneck.

[0004] Among non-noble metal catalysts, molybdenum-based oxides and other materials have attracted attention due to their tunable electronic structure. However, their common crystalline forms often suffer from poor conductivity and limited intrinsic active sites. Reducing the size of metal oxides to the sub-nano cluster scale can expose a large number of coordination unsaturated sites, significantly improving their intrinsic catalytic activity. However, sub-nano clusters have extremely high surface energy, making them prone to agglomeration, sintering, or dissolution under electrochemical conditions, resulting in poor structural stability. Carbon materials, with their good conductivity, high specific surface area, and tunable surface properties, are excellent catalyst supports. Theoretically, constructing a composite material of "carbon-supported sub-nano metal oxide clusters" is expected to combine the stable conductivity of carbon supports with the high activity of sub-nano clusters. However, the construction of this system faces multiple challenges: sub-nano clusters are prone to agglomeration or growth during synthesis and processing; it is difficult to achieve uniform, high-density, and strong bonded anchoring of clusters on the carbon support surface; the surface chemistry and microstructure of the carbon support itself significantly affect cluster dispersion and performance, making its controllable design and matching quite complex. Summary of the Invention

[0005] The purpose of this invention is to provide a carbon-supported MoO xThe preparation of cluster catalysts and their application in the electrosynthesis of hydrogen peroxide overcomes the shortcomings of existing technologies by constructing oxygen-loving MoO₂ catalysts. x The strong coupling interface between the clusters and the functionalized carbon support enables a synergistic enhancement of the activity and selectivity of the catalyst in the electrosynthesis of hydrogen peroxide, and the structure-activity relationship and catalytic mechanism are explored in depth. This paper is expected to provide a new design approach for catalyst materials in the green synthesis of hydrogen peroxide.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, the present invention provides a carbon-supported MoO x Cluster catalysts, including oxygen-doped carbon supports and MoO supported on their surfaces. x Cluster-active components; Oxygen-doped carbon support is a two-dimensional nanosheet structure, MoO x The clusters are sub-nanometer clusters with a size of <2 nm and x is 2.5-2.7.

[0007] Carbon materials possess advantages such as good electrical conductivity, high specific surface area, and tunable surface properties, making them excellent catalyst supports. Oxygen doping is an effective method for optimizing the adsorption energy of the key intermediate OOH, preventing excessive OOH adsorption from causing the O2O2 bond to break and generate water. This, in turn, thermodynamically favors the two-electron pathway of oxygen for the electrosynthesis of hydrogen peroxide. The construction of MoO2 supported on an oxygen-doped carbon support... x Cluster composite materials can combine the stable electrical conductivity of carbon supports with the high activity of sub-nanometer clusters.

[0008] In some other embodiments, oxygen-doped carbon-supported MoO x The catalyst contains 28-32 wt% Mo, preferably 30-30.5 wt% Mo; more preferably 30.3 wt% Mo.

[0009] In some other embodiments, oxygen-doped carbon support and MoO x Clusters are bonded together through interfacial electronic interactions. MoO x The clusters are uniformly dispersed in the oxygen-doped carbon support, which exposes more active sites.

[0010] In a second aspect, the present invention provides the oxygen-doped carbon-supported MoO as described in the first aspect. x The preparation method of cluster catalysts includes the following steps: (1) Dissolve urea and citric acid in deionized water and stir to prepare a solution; after removing the solvent, a precursor is obtained; oxygen-doped carbon support is obtained by heat treatment and drying. (2) Molybdenum hexacarbonyl was reacted with an oxygen-doped carbon support under closed conditions to obtain an oxygen-doped carbon-supported molybdenum precursor; MoO2 was obtained by heat treatment. x Cluster catalysts.

[0011] In some other embodiments, in step (1), the molar ratio of urea to citric acid is (45-50):1; the concentration of urea is 11-12 mol / L; the solvent removal temperature is 75-85℃, and the time is 1-3 h. Preferably, the molar ratio of urea to citric acid is (48-49):1; the concentration of urea is 11-11.5 mol / L; the solvent removal temperature is 80℃, and the time is 2 h.

[0012] In some other embodiments, in step (1), the heat treatment is carried out under an argon atmosphere, first by raising the temperature from room temperature to 500-600℃ and holding it for 1-3 hours, then raising the temperature to 850-950℃ and holding it for 0.5-1.5 hours, with a heating rate of 1-5℃·min. -1 The drying temperature is 75-85℃, and the time is 20-30 h. Preferably, the heat treatment is carried out under an argon atmosphere, first heating from room temperature to 550℃ and holding for 2 h, then heating to 900℃ and holding for 1.0 h, with a heating rate of 3℃·min. -1 The drying temperature is 80℃ and the time is 24 hours.

[0013] In some other embodiments, in step (2), the mass ratio of hexacarbonylmolybdenum to oxygen-doped carbon support is (1-3):1; the heating temperature is 75-85°C, and the time is 20-30 h. Preferably, the mass ratio of hexacarbonylmolybdenum to oxygen-doped carbon support is 2:1; the heating temperature is 80°C, and the time is 24 h.

[0014] By precisely controlling the mass ratio of molybdenum hexacarbonyl to oxygen-doped carbon support, the coverage and dispersion of active components on the support surface can be effectively adjusted, avoiding agglomeration caused by excessive loading. Prolonged closed-loop heating at a relatively low temperature allows for the full sublimation of molybdenum hexacarbonyl and its slow, uniform chemical adsorption and reaction with oxygen-doped sites on the support surface, facilitating the formation of uniformly sized and firmly anchored molybdenum precursors. This process is mild and simple to operate, achieving highly dispersed loading of molybdenum species on oxygen-doped carbon supports while avoiding high-temperature decomposition or oxidation.

[0015] In some other embodiments, in step (2), the heat treatment is carried out under an argon atmosphere, first holding at 75-85℃ for 0.5-1.5 h, then raising the temperature to 170-190℃ and holding for 1-3 h, with a heating rate of 3-6℃ / min. -1Preferably, the heat treatment is carried out under an argon atmosphere, first holding at 80°C for 1.0 h, then raising the temperature to 180°C and holding for 2 h, with a heating rate of 5°C / min. -1 .

[0016] Initially holding at a lower temperature helps remove physically adsorbed volatile substances and initially stabilizes the precursor. Then, raising the temperature and holding it there allows the hexacarbonylmolybdenum derivative to slowly decompose under argon protection and fully combine with oxygen-doped sites on the support surface, promoting the formation of fine-sized, uniformly dispersed MoO₂. x Cluster.

[0017] Thirdly, the present invention provides the oxygen-doped carbon-supported MoO as described in the first aspect. x Application of catalysts in the electrosynthesis of H₂O₂. Highly dispersed MoO₂ x The strong interaction between the clusters and the oxygen-doped carbon support enhances the conductivity and stability of the catalyst, and also improves its selectivity for the two-electron oxygen reduction reaction by regulating the electronic state of the active sites.

[0018] Fourthly, the present invention provides a method for electrosynthesizing H2O2, using the oxygen-doped carbon-supported MoO2 described in the first aspect. x Catalyst. The electrochemical synthesis of H2O2 exhibits high Faradaic efficiency, high H2O2 yield, and good cycle stability.

[0019] The beneficial effects of this invention are: (1) The catalyst of the present invention uses oxygen-doped carbon with a two-dimensional nanosheet structure as a support, and the supported MoO x The active component consists of sub-nanometer clusters with a size of less than 2 nm, which greatly exposes the active sites and significantly improves atom utilization efficiency. Simultaneously, the strong interfacial electronic interactions that may form between the support and the clusters can effectively modulate the electronic structure of the active centers, enhancing their intrinsic activity and stability. This improves the activity, selectivity, and durability of the catalyst in reactions such as the electrochemical synthesis of hydrogen peroxide.

[0020] (2) The preparation method of the catalyst of the present invention utilizes the low-temperature sublimation and diffusion of molybdenum hexacarbonyl under closed conditions to achieve uniform pre-anchoring of the molybdenum precursor on the support; then, through programmed temperature thermal decomposition, it is converted in situ into highly dispersed, small-sized (less than 2 nm) MoO under mild conditions. x Sub-nanometer clusters. This preparation method is simple, mild, requires no complex equipment, and avoids the use of strong acids or organic solvents. Through precursor design and stepwise pyrolysis, the size, dispersion, and metal-support interface of the active components are effectively controlled, providing a green and controllable synthesis strategy for obtaining high-performance catalytic materials.

[0021] (3) The present invention uses oxygen-doped carbon-supported MoO x The catalyst significantly enhanced the activity, selectivity, and stability of ORR electrosynthesis of H2O2. MoO x The ORR half-wave potential of -OC is 0.76 V, and the Faraday efficiency of H2O2 is as high as 99%. Attached Figure Description

[0022] 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.

[0023] Figure 1 The MoO prepared according to the present invention x - SEM images of the OC sample at different scales, where a is the SEM image at a 1 μm scale and b is the SEM image at a 500 nm scale; Figure 2 The MoO prepared according to the present invention x -HR-TEM image of the OC sample; Figure 3 The MoO prepared according to the present invention x - Aberration-corrected HAADF-STEM image of OC sample; Figure 4 The OC and MoO prepared by this invention x XRD patterns of -OC and MoO3-OC samples; Figure 5 The images shown are HR-TEM images of the MoO3-OC sample prepared in this invention, where a and b are HR-TEM images and c is an enlarged lattice fringe image. Figure 6 The XRD patterns are of the MoO3-OC-400 and MoO2-OC-500 samples prepared in this invention. Figure 7 The MoO prepared according to the present invention x EPR plots of -OC and MoO3-OC samples; Figure 8 The OC sample and MoO prepared in this invention x LSV curves of electrosynthesis of H2O2 from -OC sample and MoO3-OC sample; Figure 9 The OC sample and MoO prepared in this invention x -OC sample and MoO3-OC sample: percentage of hydrogen peroxide yield and number of electrons transferred; Figure 10 The MoO prepared according to the present invention x -It stability test curve of OC sample; Figure 11 The MoO prepared according to the present invention x -Faraday efficiency plot of hydrogen peroxide for OC sample; Among them, MoO x -OC sample is the sample prepared in Example 1, OC sample is the sample prepared in Comparative Example 1, MoO3-OC sample is the sample prepared in Comparative Example 2, MoO3-OC-400 sample is the sample prepared in Comparative Example 3, and MoO2-OC-500 sample is the sample prepared in Comparative Example 4. Detailed Implementation

[0024] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0025] As mentioned earlier, existing highly active catalysts in the electrosynthesis of hydrogen peroxide (such as platinum-mercury and palladium-mercury alloys) rely on expensive precious metals, resulting in excessively high costs; while inexpensive non-precious metal materials (such as traditional molybdenum oxide) suffer from poor conductivity and limited active sites. Reducing the size of metal oxides to the sub-nanometer scale can improve intrinsic activity, but their extremely high surface energy makes clusters prone to agglomeration and deactivation under reaction conditions, resulting in insufficient stability.

[0026] This invention successfully prepared oxygen-doped carbon-supported sub-nanometer molybdenum oxide clusters (MoO₂) by combining pre-adsorption with low-temperature pyrolysis. x -OC) composite material. This composite material utilizes the excellent conductivity and stable structure of functionalized carbon support to provide stable anchoring sites for high surface energy sub-nanometer molybdenum oxide clusters. By constructing strongly interacting interfacial couplings, it synergistically enhances the catalytic activity, selectivity, and long-term stability of the catalyst in the electrosynthesis of hydrogen peroxide. This provides a new material design approach for developing efficient, stable, and low-cost non-precious metal hydrogen peroxide synthesis catalysts.

[0027] Example 1 This embodiment provides an oxygen-doped carbon-supported MoO₂. x The catalyst and its preparation method specifically include the following steps: (1) Preparation of OC: 10 g (0.17 mol) of urea and 0.67 g (3.49 mmol) of anhydrous citric acid were dissolved in 15 mL of deionized water and stirred at room temperature until a colorless and transparent solution was obtained. Then, the solution was stirred in an 80 °C water bath for 2 h to completely evaporate the solvent. The white solid product was collected and placed in a tube furnace for heat treatment. The heat treatment process consisted of two stages: under an argon atmosphere, the temperature was first raised from room temperature to 550 °C and held for 2 h, and then raised to 900 °C and held for 1 h, with a heating rate of 3 °C·min. -1The collected black powder product was dried in an oven at 80 °C for 24 h and named OC.

[0028] (2) MoO x Preparation of OC: 40 mg (0.15 mmol) of molybdenum hexacarbonyl was placed in a 3 mL open glass bottle. This bottle was then placed inside a 20 mL glass bottle containing 20 mg of OC support. The bottles were sealed and placed in a drying oven at 80 °C for 24 h. After natural cooling, the molybdenum carbonyl precursor powder supported on the OC support was collected. Subsequently, a certain amount of sample was placed in a tube furnace and heated under an argon atmosphere at 80 °C and 180 °C for 1 and 2 h, respectively, with a heating rate of 5 °C / min. -1 The final black product was named MoO. x -OC.

[0029] Based on the peak area after fitting the Mo peaks in XPS, x was calculated to be 2.5-2.7, and the Mo content measured by ICP-MS was 30.3 wt%.

[0030] Comparative Example 1 Unlike Example 1, only the OC support was prepared as a catalyst. The preparation method of the OC support was the same as that of the OC support in step (1) of Example 1.

[0031] Comparative Example 2 Unlike Example 1, the MoO3-OC catalyst was prepared. Specifically, the preparation steps of MoO3-OC-300 are as follows: The carbonyl molybdenum precursor powder prepared in step (2) of Example 1 was placed in a tube furnace and calcined at 80 °C and 180 °C for 1 and 2 h respectively under an argon atmosphere, with a heating rate of 5 °C·min. -1 Subsequently, at 5℃·min -1 The temperature was rapidly increased to 300℃ and held for 10 min. The resulting black product was named MoO3-OC. The only difference in this process was the final pyrolysis temperature; all other steps remained the same.

[0032] Comparative Example 3 Unlike Example 1, a MoO3-OC-400 catalyst was prepared. Specifically, the preparation steps of MoO3-OC-400 are as follows: The carbonyl molybdenum precursor powder prepared in step (2) of Example 1 was placed in a tube furnace and calcined at 80 °C and 180 °C for 1 and 2 h respectively under an argon atmosphere, with a heating rate of 5 °C·min. -1 Subsequently, at 5℃·min -1The temperature was rapidly increased to 400℃ and held for 10 min. The resulting black product was named MoO3-OC-400. The only difference in this process was the final pyrolysis temperature; all other steps remained the same.

[0033] Comparative Example 4 Unlike Example 1, a MoO2-OC-500 catalyst was prepared. Specifically, the preparation steps of MoO2-OC-500 are as follows: The carbonyl molybdenum precursor powder prepared in step (2) of Example 1 was placed in a tube furnace and calcined at 80 °C and 180 °C for 1 and 2 h respectively under an argon atmosphere, with a heating rate of 5 °C·min. -1 Subsequently, at 5℃·min -1 The temperature was rapidly increased to 500℃ and held for 10 min. The resulting black product was named MoO2-OC-500. The only difference in this process was the final pyrolysis temperature; all other steps remained the same.

[0034] Performance characterization: (1) Morphological and structural characterization: The prepared MoO was analyzed using scanning electron microscopy (SEM). x The morphology of the OC catalyst was observed. The OC support was an ultrathin two-dimensional nanosheet structure. Figure 1 (a and b in the text), in anchoring high-density MoO x The clustered carrier retains its layered structure, which is beneficial for mass transfer of reactants and exposure of active sites. Figure 2 High-resolution transmission electron microscopy (HR-TEM) images confirmed MoO x It consists of sub-nanometer clusters smaller than 2 nm. High-angle annular dark-field scanning transmission microscopy (HAADF-STEM) with spherical aberration correction further revealed MoO₂. x Clusters were uniformly distributed on the surface of the OC support without obvious aggregation. x The average size of the clusters is 1.59 nm. Figure 3 ).

[0035] MoO x The XRD pattern of -OC shows only a typical graphitic carbon characteristic peak at 26.8°, without any crystallization peaks of Mo-related compounds, which is consistent with MoO. x The small cluster size exceeding the XRD detection limit is related to factors such as the small size of the clusters, which is consistent with the observations of aberration-corrected electron microscopy. The positive shift of the diffraction peak at 25.7° compared to the OC sample indicates that MoO2... x Strong interfacial interactions exist between the clusters and the OC support. This interfacial stress may lead to shrinkage of the interplanar spacing, causing diffraction peaks to shift to higher angles. Furthermore, thermally driven processes will further enhance the dispersion of highly dispersed MoO.x The clusters transform into long-range ordered MoO3, exhibiting sharp characteristic diffraction peaks at positions such as 23.4, 25.8, 33.2, and 39.7°, indicating that the clusters transform into larger particles through Ostwald ripening. Figure 4 The high-resolution TEM images further corroborate this result. Figure 5 (ac in the text).

[0036] from Figure 6 The XRD pattern reveals that thermal drive not only increased the crystallinity of the material but also triggered a redox-induced phase transition process; at 500℃, MoO3 thermally decomposed and reduced to MoO2. In the electron paramagnetic resonance (EPR) spectrum, MoO... x Both the -OC and MoO3-OC samples showed EPR around g = 2.000, indicating the presence of oxygen vacancies, and MoO3-OC samples also showed EPR. x The -OC sample exhibits a stronger EPR signal, indicating more edge defects and uncoordinated electrons, which will increase the number of Mo sites exposed at oxygen vacancies during the electrosynthesis of hydrogen peroxide. x The signal of the -OC sample at g = 1.929 corresponds to Mo 5+ The generation ( Figure 7 ).

[0037] (2) MoO x -Activity and selectivity of electrosynthesis of H2O2 in OC samples: To evaluate MoO x The activity and selectivity of the -OC sample in the electrosynthesis of H2O2 were measured by linear sweep voltammetry (LSV) in 0.1 M KOH solution using a standard three-electrode system and a rotating ring-disk electrode (RRDE). The scan rate was 5 mV / s. -1 The polarization curves of each sample obtained at a rotation speed of 1600 rpm are shown below. Figure 8 As shown. MoO x The -OC sample exhibited significant electrocatalytic activity for the synthesis of H2O2 via two-electron ORR, with an onset potential of 0.76 V, which was superior to MoO3-OC and OC catalysts.

[0038] The electron transfer number (n) and hydrogen peroxide yield were investigated using RRDE testing. Figure 9 As shown, in MoO x In the ORR reaction of the -OC sample, the number of electrons transferred per oxygen atom is around 2.0, indicating that there are 2 electrons transferred. - Selectivity. At 0.65 V vs. RHE, MoO x The H2O2 yield of -OC is as high as 99%, which further indicates that the catalyst has high H2O2 selectivity.

[0039] It is worth noting that after 12 hours of stability testing, MoO x - The disk current and ring current of the OC catalyst can still be maintained at 0.38 and 0.12 mA, respectively, and the H2O2 yield is higher than 92.5%. Figure 10 It exhibits excellent stability. Furthermore, the Faraday efficiency of H₂O₂ at different potentials was calculated. MoO x The -OC catalyst exhibits a H2O2 faradaic efficiency higher than 84.1% in the potential range of 0.15–0.65 V vs. RHE, and the H2O2 faradaic efficiency can reach 99.8% at 0.65 V vs. RHE. Figure 11 Therefore, the prepared MoO x -OC catalysts exhibit good electrocatalytic activity, selectivity, and stability in the synthesis of H2O2 via ORR.

[0040] In summary, a high-density MoO2 supported on oxygen-modified carbon ultrathin nanosheets was synthesized through a pre-adsorption and low-temperature pyrolysis strategy. x Cluster catalysts. Compared with MoO3-OC catalysts, the strong interfacial electronic interactions between sub-nanometer clusters and the oxygen-carbon support, as well as the increased oxygen vacancy concentration, significantly enhance the activity, selectivity, and stability of ORR electrosynthesis of H2O2. Experimental results show that MoO... x The ORR half-wave potential of -OC is 0.76 V, and the Faraday efficiency of H2O2 is as high as 99%. This work provides a new approach for the design and application of sub-nanometer metal oxide cluster catalysts.

[0041] The above are merely preferred embodiments of the present invention and are not intended to limit the present 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. An oxygen-doped carbon-supported MoO x Catalyst, characterized in that, Including oxygen-doped carbon supports and supported MoO x Cluster-active components; The oxygen-doped carbon support is a two-dimensional nanosheet structure, and the MoO x The clusters are sub-nanometer clusters with a size of <2 nm and x is 2.5-2.

7.

2. The oxygen-doped carbon-supported MoO₂ according to claim 1 x Catalyst, characterized in that, The oxygen-doped carbon-supported MoO x The Mo content in the catalyst is 28-32 wt%.

3. The oxygen-doped carbon-supported MoO according to claim 1 x Catalyst, characterized in that, The oxygen-doped carbon support and MoO x Clusters bind together through interfacial electronic interactions.

4. An oxygen-doped carbon-supported MoO according to any one of claims 1-3 x A method for preparing a catalyst, characterized in that, Includes the following steps: (1) Dissolve urea and citric acid in deionized water and stir to make a solution; After removing the solvent, a precursor is obtained; oxygen-doped carbon support is obtained by heat treatment and drying. (2) Molybdenum hexacarbonyl was reacted with an oxygen-doped carbon support under closed conditions to obtain an oxygen-doped carbon-supported molybdenum precursor; MoO2 was obtained by heat treatment. x Cluster catalysts.

5. The oxygen-doped carbon-supported MoO according to claim 4 x A method for preparing a catalyst, characterized in that, In step (1), the molar ratio of urea to citric acid is (45-50):1; the concentration of urea is 11-12 mol / L; the temperature for solvent removal is 75-85℃ and the time is 1-3 h.

6. The oxygen-doped carbon-supported MoO according to claim 4 x A method for preparing a catalyst, characterized in that, In step (1), the heat treatment is carried out under an argon atmosphere, first by raising the temperature from room temperature to 500-600℃ and holding it for 1-3 hours, then raising the temperature to 850-950℃ and holding it for 0.5-1.5 hours, with a heating rate of 1-5℃ / min. -1 ; The drying temperature is 75-85℃, and the time is 20-30 h.

7. The oxygen-doped carbon-supported MoO according to claim 4 x A method for preparing a catalyst, characterized in that, In step (2), the mass ratio of the hexacarbonyl molybdenum to the oxygen-doped carbon support is (1-3):1; The heating reaction is carried out at a temperature of 75-85℃ for 20-30 hours.

8. The oxygen-doped carbon-supported MoO according to claim 4 x A method for preparing a catalyst, characterized in that, In step (2), the heat treatment is carried out under an argon atmosphere, first holding at 75-85℃ for 0.5-1.5 h, then raising the temperature to 170-190℃ and holding for 1-3 h, with a heating rate of 3-6℃·min. -1 .

9. An oxygen-doped carbon-supported MoO according to any one of claims 1-3 x Application of catalysts in the electrosynthesis of H2O2.

10. A method for electrosynthesizing H2O2, characterized in that, MoO supported on oxygen-doped carbon as described in any one of claims 1-3 x catalyst.

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