A kind of front transition metal oxide nanoparticles and its preparation method and oxygen reduction synthesis hydrogen peroxide application
By preparing pre-transition metal oxide nanoparticle catalysts with a particle size of 10-100 nm, the shortcomings of noble metal alloys and carbon-based materials were overcome, and large-scale preparation of hydrogen peroxide with high selectivity and stability was achieved. This simplified the preparation process and avoided environmental pollution and safety hazards.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HAINAN UNIV
- Filing Date
- 2026-03-03
- Publication Date
- 2026-06-09
AI Technical Summary
In the existing technology, precious metal alloy catalysts are expensive and have poor stability, while carbon-based material catalysts have short lifespans, making it difficult to meet the needs of large-scale hydrogen peroxide preparation. Furthermore, existing pre-transition metal oxide catalysts have insufficient performance and stability in alkaline media, and the preparation process poses environmental pollution and safety hazards.
A 10-100 nm particle catalyst for the synthesis of hydrogen peroxide by oxygen reduction was prepared by stirring a soluble pre-transition metal salt and ammonium chloride in a solvent, heating the mixture, and then calcining it in an inert gas atmosphere.
It achieves high selectivity and stability, with a hydrogen peroxide selectivity of up to 99.8% and a Faraday efficiency of up to 99.6% in alkaline media. It is suitable for large-scale industrial production, and the preparation process is simple, safe and environmentally friendly.
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Figure CN122166813A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrosynthesis technology of hydrogen peroxide in alkaline media, specifically a pre-transition metal oxide nanoparticle, its preparation method, and its application in oxygen reduction synthesis of hydrogen peroxide. Background Technology
[0002] Hydrogen peroxide (H2O2) is an important green industrial chemical widely used in papermaking, textiles, printing and dyeing, water quality improvement, and semiconductors. Traditional methods for preparing H2O2 mostly employ the anthraquinone oxidation process. While this process is mature and can produce H2O2 on a large scale and automatically, it also suffers from high energy consumption, environmental pollution, and safety hazards. In contrast, preparing H2O2 via an electrochemical two-electron oxygen reduction reaction effectively avoids large-scale transportation of H2O2, enabling on-site production and use. This method is also safe, portable, environmentally friendly, and energy-efficient. Nevertheless, the electrochemical oxygen reduction process for H2O2 preparation requires a catalyst to lower the reaction energy barrier and achieve high selectivity. Currently, the catalysts used in the electrochemical oxygen reduction process for H2O2 preparation are mainly noble metal alloys and single-atom metal materials. While both types of materials exhibit excellent H2O2 selectivity, the high cost and scarcity of precious metal alloy catalysts significantly limit their future large-scale application; while single-atom metal catalysts suffer from short service life due to unavoidable carbon corrosion, making them unsuitable for practical applications. Therefore, there is an urgent need to develop new, inexpensive, and structurally stable materials with high H2O2 selectivity.
[0003] Pre-transition metal oxides are widely available and structurally stable, and their relatively low d-electron count facilitates moderate interactions with OOH intermediates. Therefore, they are promising catalysts for the electrosynthesis of H₂O₂. Studies have shown that while pre-transition metal oxides exhibit good H₂O₂ selectivity, they still fall short of the requirements for practical applications.
[0004] Carneiro et al. prepared a Nb₂O₅-rG composite catalyst using graphene oxide as a support via a hydrothermal method (Carneiro, JF; Paulo, MJ; Siaj, M.; Tavares, AC; Lanza, MRV; Journal of Catalysis 2015, 332, 51-61.). The catalyst exhibited only 75% H₂O₂ selectivity in 0.1 M NaOH electrolyte, significantly lower than the average reported to date. Furthermore, this study only covered electrochemical rotating disk testing and did not verify its H₂O₂ yield and Faradaic efficiency in gas diffusion electrode (GDE) devices.
[0005] Chen et al. prepared a Mn-TiO2 nanoparticle catalyst via a reflux method (Chen Q, Ma C, Yan S, Liang J, Dong K, Luo Y, et al. ACS Applied Materials & Interfaces. 2021;13(39):46659-64). This catalyst exhibited excellent catalytic performance in 0.1 M KOH electrolyte, with an H2O2 selectivity as high as 92.7%, and the performance of the electrochemical oxygen reduction assay was highly consistent with that of the H-type battery device. However, it should be noted that the preparation and application of this catalyst face several challenges: the Mn doping amount needs to be precisely controlled during preparation to avoid the formation of manganese oxide impurities that weaken the catalytic efficiency; at the same time, the dissolution of Mn is detrimental to the long-term stability of the catalyst. Furthermore, the catalyst performance depends on a specific potential window. Although the tested performance is good, there is still potential competition from side reaction pathways, presumably related to the competitive consumption of OOH intermediates at high negative potentials, which also affects its Faraday efficiency in practical device applications.
[0006] Jiang et al. prepared an α-MoO2 compound by calcining ammonium molybdate tetrahydrate under a hydrogen-argon mixed atmosphere. 3-X The catalyst (Jiang H, Zhang C, Wang Z, et al. Applied Catalysis A:General, 2023, 661: 119242.) exhibits a 93% selectivity for H2O2 in 0.1 M KOH electrolyte. However, in device testing, the catalyst's Faradaic efficiency was only 87%, showing a significant difference. This result indicates that the catalyst is subject to competitive consumption by side reactions during the reaction process, resulting in incomplete conversion of electrons into H2O2 formation and reduced overall energy utilization efficiency. Furthermore, the current density of this catalyst in device testing was only 6 mAcm⁻¹. -2 This method cannot meet the requirements for large-scale preparation of hydrogen peroxide. Furthermore, the synthesis of this material uses flammable and explosive hydrogen gas, which is not conducive to scale-up production.
[0007] Hou et al. prepared an H-TiO2 catalyst using an acid-metal treatment method (Hou N, Ye K, Wang M, et al. Angewandte Chemie International Edition, 2026, 65(3): e19411.). This catalyst achieved a 95% selectivity for H2O2 in 0.5 M NaSO4 electrolyte; however, after a 40,000-s chronoamperometry stability test, the selectivity decreased to 85%. This result indicates that the high selectivity of the catalyst has a certain long-term effect but is not absolutely stable. Although the Ti-O2C-H bifunctional active center constructed by lattice hydrogen engineering did not completely deactivate, slight imbalances in the lattice hydrogen proton supply and demand, slight oxidation of the active center surface, or impurity adsorption may occur during long-term electrocatalysis, leading to a slight weakening of the competitive advantage of the two-electron oxygen reduction pathway. Furthermore, current research only tested and verified the oxygen reduction performance of this catalyst in neutral media, and has not yet addressed the evaluation of its oxygen reduction catalytic performance in alkaline media or its practical application scenarios.
[0008] Chinese patent (publication number: CN120330791 A) discloses a method for preparing a metal oxide heterojunction catalyst and its application in electrocatalytic hydrogen peroxide production in aquaculture. First, zinc oxide is obtained through a hydrothermal reaction using soluble zinc salt and urea as raw materials. Then, soluble nickel salt and zinc oxide are used as raw materials, and a co-precipitation reaction is conducted to separate the solvent and obtain the precursor. Finally, the precursor is calcined to obtain a metal oxide heterojunction. The NiO / ZnO-450 catalyst prepared by this method achieved an H2O2 yield of 0.942 μmol / min under 2.9V vs. RHE conditions. -1 cm -2 However, this catalyst is used to produce H2O2 via electrocatalytic water oxidation, and its application has not yet been extended to electrocatalytic oxygen reduction for H2O2 production. Furthermore, the catalyst material involved in this invention is a post-transition metal oxide, rather than a pre-transition metal oxide.
[0009] Chinese invention patent (publication number: CN113774426 A) reports a preparation process for a hydrogen-doped titanium dioxide electrocatalyst. First, using tetrabutyl titanate as the titanium source, a titanium dioxide (TiO2) precursor with exposed high-energy {001} crystal faces is synthesized in a hydrofluoric acid (HF) aqueous solution via a solvothermal method. Subsequently, the TiO2 precursor is modified by hydrogen doping through an acid-metal reduction treatment strategy, incorporating hydrogen elements into the TiO2 lattice, ultimately yielding a high-energy, crystal-faceted exposed hydrogen-doped titanium dioxide catalyst (H-TiO2). This catalyst achieves a 90% H2O2 selectivity in 0.1M KOH electrolyte. However, this preparation route has two significant drawbacks: first, the crystal facet control process requires a 20%–30% HF solution, which is highly corrosive, posing operational safety hazards and environmental problems; second, the overall process requires two steps—solvothermal reaction and acid-metal reduction treatment—making the process relatively cumbersome and unsuitable for large-scale preparation.
[0010] In summary, while research on the preparation methods of pre-transition metal oxides and their performance in the oxygen reduction synthesis of hydrogen peroxide has been conducted, there are still significant shortcomings in the research on the preparation of pre-transition metal oxide nanoparticle catalysts with both high hydrogen peroxide selectivity and excellent stability through simplified synthesis strategies, and in their application in devices for the production of hydrogen peroxide via oxygen reduction. Furthermore, the preparation processes described in existing literature or patents pose environmental pollution and safety hazards. Therefore, developing a simple, safe, and environmentally friendly pre-transition metal oxide nanoparticle catalyst preparation scheme with high H2O2 selectivity and excellent stability, and applying it to devices for the oxygen reduction synthesis of hydrogen peroxide, is a crucial direction that urgently needs breakthrough in this research field. Summary of the Invention
[0011] The purpose of this invention is to overcome the shortcomings of the prior art. In view of the high cost of noble metal alloys and the poor stability of carbon-based materials in the current electrosynthesis of hydrogen peroxide, this invention proposes a simple, safe, low-cost method for preparing pre-transition metal oxide nanoparticle catalysts that is suitable for large-scale production. This method is of great significance for promoting the commercial development of oxygen reduction synthesis of hydrogen peroxide.
[0012] To achieve the above objectives, the technical solution provided by the present invention is as follows: The present invention provides a method for preparing pre-transition metal oxide nanoparticles, wherein a soluble pre-transition metal salt and ammonium chloride are dissolved in a solvent, stirred thoroughly and sonicated, and heated and stirred to obtain a precursor. The precursor is then placed in a tube furnace and calcined in an inert gas atmosphere to finally obtain pre-transition metal oxide nanoparticles.
[0013] Furthermore, the soluble pre-transition metal salt includes any one or more of the following: scandium nitrate, scandium chloride, scandium acetylacetonate, zirconium oxychloride, zirconium oxynitrate, zirconium sulfate, zirconium acetate, zirconium acetylacetonate, hafnium dichloride, hafnium nitrate, hafnium sulfate, hafnium acetylacetonate, tungstic acid, ammonium tungstate, ammonium metatungstate, ammonium paratungstate, sodium tungstate, sodium metatungstate, sodium paratungstate, potassium tungstate, potassium metatungstate, potassium paratungstate, lithium tungstate, lithium metatungstate, and lithium paratungstate.
[0014] Furthermore, the molar ratio of the soluble pre-transition metal salt to ammonium chloride is between 1:1 and 1:50.
[0015] Furthermore, the process of dissolving the soluble pre-transition metal salt and ammonium chloride in 10–50 mL of water or ethanol also includes ultrasonic or stirring dissolution for 0.5–3 hours.
[0016] Furthermore, the solvent is evaporated by using a magnetic heating stirrer, water bath, oil bath, or sand bath, with the heating temperature being 80-120℃ and the heating time being 5-8 hours.
[0017] Furthermore, the calcination atmosphere is argon or nitrogen, the calcination temperature is 300-1200℃, and the calcination time is 0.5-3 h.
[0018] The nanoparticles prepared by the method of this invention are different from those of the prior art, so the nanoparticles of this invention are also within the scope of protection, with a particle size of 10-100 nm.
[0019] The present invention also provides the application of the nanoparticles as a catalyst for the oxygen reduction synthesis of hydrogen peroxide.
[0020] Compared with existing technologies, the preparation of pre-transition metal oxide nanoparticles and their application in the oxygen reduction synthesis of hydrogen peroxide according to the present invention have the following advantages: (1) The method provided by the present invention can prepare different pre-transition metal oxide nanoparticle catalysts in a simple, safe and low-energy way. It is a universal preparation method that is suitable for large-scale industrial production.
[0021] (2) The catalysts prepared by the method provided in this invention are structurally stable and resistant to alkali corrosion. Furthermore, their d-electron counts are relatively low, which facilitates moderate interaction with OOH intermediates, resulting in excellent hydrogen peroxide selectivity and catalytic stability. The catalysts prepared in this invention exhibit a hydrogen peroxide selectivity of up to 99.8% in a rotating ring disk test and a high selectivity in a flow cell at 100 mA cm⁻¹. -2 The Faraday efficiency reached 99.6% in constant current testing, and remained at 96% within 24 hours, making it one of the best catalysts for preparing hydrogen peroxide in alkaline media. Attached Figure Description
[0022] Figure 1 This is a transmission electron microscope (TEM) image of scandium trioxide, a pre-transition metal oxide, prepared in Example 1.
[0023] Figure 2 This is a high-resolution transmission electron microscope (HR-TEM) image of scandium trioxide, a pre-transition metal oxide, prepared in Example 1.
[0024] Figure 3 The image shows the X-ray diffraction pattern of scandium trioxide, a pre-transition metal oxide, prepared in Example 1.
[0025] Figure 4 The image shows the polarization curve of scandium trioxide, the pre-transition metal oxide prepared in Example 1, in an alkaline medium.
[0026] Figure 5 This is a graph showing the selectivity of hydrogen peroxide for the scandium trioxide, a pre-transition metal oxide prepared in Example 1, in an alkaline medium, as calculated.
[0027] Figure 6 This is a graph showing the selectivity of hydrogen peroxide after stabilizing the scandium trioxide, a pre-transition metal oxide prepared in Example 1, in an alkaline medium.
[0028] Figure 7 The graph shows the Faraday efficiency of the scandium trioxide, a pre-transition metal oxide prepared in Example 1, under different constant current tests in a flow cell.
[0029] Figure 8 The image shows the Faraday test diagram of scandium trioxide, a pre-transition metal oxide prepared in Example 1, in a constant current test in a flow cell.
[0030] Figure 9 This is a graph showing the selectivity of hydrogen peroxide calculated for the pre-transition metal oxide zirconium dioxide prepared in Example 2 in an alkaline medium.
[0031] Figure 10 This is a graph showing the selectivity of hydrogen peroxide calculated for the pre-transition metal oxide hafnium dioxide prepared in Example 3 in an alkaline medium.
[0032] Figure 11 This is a graph showing the selectivity of hydrogen peroxide calculated for the tungsten trioxide, a pre-transition metal oxide prepared in Example 4, in an alkaline medium. Detailed Implementation
[0033] The following description, in conjunction with specific embodiments, provides a complete and clearer explanation of this technical solution. Unless otherwise specified, all technical means employed are existing technologies. Unless otherwise specified, the materials and reagents used in the embodiments of this invention are commercially available.
[0034] Example 1: Sc2O3 catalyst (1) Preparation of Sc2O3 precursor 0.1–1 mmol scandium acetate hydrate and 1–10 mmol ammonium chloride were weighed and dissolved in 50 mL of ultrapure water to prepare a precursor solution. The solution was stirred for 10–30 min, followed by sonication for 0.5–3 h. After heating and stirring, the Sc2O3 precursor was obtained.
[0035] (2) Preparation of Sc2O3 catalyst Weigh 0.1~0.5 g of Sc2O3 precursor and place it in a quartz boat. Then place the quartz boat in a tube furnace with a fitting tube. First, purge the air in the quartz tube with argon gas for 30~60 min. Raise the temperature from room temperature to 700~900℃ at a rate of 1~5℃ / min. After reaching the target temperature, hold it for 2 h. Finally, allow it to cool naturally to room temperature to obtain the desired catalyst sample.
[0036] (3) Structural morphology and elemental characterization of the catalyst The morphology of the catalyst nanoparticles can be seen from field emission transmission electron microscopy (TEM). Figure 1 ), and the lattice fringes of scandium trioxide can be clearly seen using a high-resolution transmission electron microscope. Figure 2 ), and calculations further confirmed that it was a Sc2O3 catalyst.
[0037] X-ray diffraction was used to characterize the elemental composition of the Sc2O3 nanoparticle catalyst. Figure 3 ).from Figure 3 It can be seen that the prepared material corresponds to the standard card, further confirming that the catalyst is Sc2O3.
[0038] (4) ORR performance test of catalyst The polarization curves were recorded by linear voltammetric scanning using a three-electrode system in oxygen- and nitrogen-saturated 0.1 M KOH at a scan rate of 10 mV / s and an electrode rotation speed of 1600 rpm. Figure 4 The calculated selectivity of hydrogen peroxide ( Figure 5 The stability of the synthesized hydrogen peroxide was tested after 100,000 cyclic voltammetric scans at 0.1–0.7 V. Figure 6 ).
[0039] Unless otherwise specified, the methods for testing the selectivity of the catalysts involved in this invention for hydrogen peroxide in alkaline media are the same as those described above.
[0040] The catalyst prepared in this embodiment exhibits excellent hydrogen peroxide selectivity and stability in alkaline media, with an initial hydrogen peroxide selectivity of up to 93%. After 100,000 cycles of cyclic voltammetry testing, its hydrogen peroxide selectivity reaches as high as 99.8%. In a flow cell at 100 mA cm⁻¹... -2 In constant current testing, the Faraday efficiency reached 99.6% ( Figure 7 Furthermore, the Faraday efficiency remains as high as 96% within 24 hours. Figure 8 ).
[0041] Example 2: ZrO2 catalyst (1) Preparation of ZrO2 precursor 0.1–1 mmol of zirconium oxychloride octahydrate and 1–10 mmol of ammonium chloride were weighed and dissolved in 50 mL of ultrapure water to prepare a precursor solution. The solution was stirred for 10–30 min, followed by sonication for 0.5–3 h. After heating and stirring, the ZrO2 precursor was obtained.
[0042] (2) Preparation of ZrO2 catalyst Weigh 0.1~0.5 g of ZrO2 precursor and place it in a quartz boat. Then place the quartz boat in a tube furnace with a fitting tube. First, purge the air in the quartz tube with argon gas for 30~60 min. Raise the temperature from room temperature to 700~1000℃ at a rate of 1~5℃ / min. After reaching the target temperature, hold it for 2 h. Finally, allow it to cool naturally to room temperature to obtain the desired catalyst sample.
[0043] (3) ORR performance test of catalyst A three-electrode system was used, and linear voltammetric scans were performed in 0.1 M KOH saturated with oxygen and nitrogen, respectively. The polarization curves recorded were obtained by scanning at a rate of 10 mV / s and an electrode rotation speed of 1600 rpm. The hydrogen peroxide selectivity was then calculated. Figure 9 ).
[0044] The catalyst prepared in this embodiment exhibits excellent hydrogen peroxide selectivity in alkaline media, with a selectivity of 92-98.5% in the potential range of 0.1-0.5 V vs. RHE.
[0045] Example 3: HfO2 catalyst (1) Preparation of HfO2 precursor Weigh 0.1–1 mmol hafnium dichloride octahydrate and 1–10 mmol ammonium chloride respectively and dissolve them in 50 mL of ultrapure water to prepare a precursor solution. Stir for 10–30 min, then sonicate for 0.5–3 h. After heating and stirring, obtain the HfO2 precursor.
[0046] (2) Preparation of HfO2 catalyst Weigh 0.1~0.5 g of HfO2 precursor and place it in a quartz boat. Then place the quartz boat in a tube furnace with a fitting tube. First, purge the air in the quartz tube with argon gas for 30~60 min. Raise the temperature from room temperature to 700~1100℃ at a rate of 1~5℃ / min. After reaching the target temperature, hold it for 2 h. Finally, allow it to cool naturally to room temperature to obtain the desired catalyst sample.
[0047] (3) ORR performance test of catalyst A three-electrode system was used, and linear voltammetric scans were performed in 0.1 M KOH saturated with oxygen and nitrogen, respectively. The polarization curves recorded were obtained by scanning at a rate of 10 mV / s and an electrode rotation speed of 1600 rpm. The hydrogen peroxide selectivity was then calculated. Figure 10 ).
[0048] The catalyst prepared in this embodiment exhibits excellent hydrogen peroxide selectivity in alkaline media, with a selectivity of 92.5-99% in the potential range of 0.1-0.5 V vs. RHE.
[0049] Example 4: WO3 catalyst (1) Preparation of WO3 precursor 0.1–1 mmol of ammonium metatungstate hydrate and 1–10 mmol of ammonium chloride were weighed and dissolved in 50 mL of ultrapure water to prepare a precursor solution. The solution was stirred for 10–30 min, followed by sonication for 0.5–3 h. After heating and stirring, the WO3 precursor was obtained.
[0050] (2) Preparation of WO3 catalyst Weigh 0.1~0.5 g of WO3 precursor and place it in a quartz boat. Then place the quartz boat in a tube furnace with a fitting tube. First, purge the air in the quartz tube with argon gas for 30~60 min. Raise the temperature from room temperature to 700~1100℃ at a rate of 1~5℃ / min. After reaching the target temperature, hold it for 2 h. Finally, allow it to cool naturally to room temperature to obtain the desired catalyst sample.
[0051] (3) ORR performance test of catalyst A three-electrode system was used, and linear voltammetric scans were performed in 0.1 M KOH saturated with oxygen and nitrogen, respectively. The polarization curves recorded were obtained by scanning at a rate of 10 mV / s and an electrode rotation speed of 1600 rpm. The hydrogen peroxide selectivity was then calculated. Figure 11 ).
[0052] The catalyst prepared in this embodiment exhibits excellent hydrogen peroxide selectivity in alkaline media, with a selectivity of 93.5-99% in the potential range of 0.1-0.5 V vs. RHE.
[0053] It should be noted that the soluble pre-transition metal salt of the present invention can be any one of the following: scandium nitrate, scandium chloride, scandium acetylacetonate, zirconium oxychloride, zirconium oxynitrate, zirconium sulfate, zirconium acetate, zirconium acetylacetonate, hafnium dichloride, hafnium nitrate, hafnium sulfate, hafnium acetylacetonate, tungstic acid, ammonium tungstate, ammonium metatungstate, ammonium paratungstate, sodium tungstate, sodium metatungstate, sodium paratungstate, potassium tungstate, potassium metatungstate, potassium paratungstate, lithium tungstate, lithium metatungstate, and lithium paratungstate. They can also be used in combination, and the mixture can be prepared in any mass. The ratio, for example, 1:1, 1:2, etc., can be between 1:1 and 1:50, such as 1:1, 1:50, 1:30. The soluble pre-transition metal salt and ammonium chloride are dissolved in 10 to 50 mL of water or ethanol, such as 10, 50, 30 mL, etc. Since the performance of the obtained catalysts is within the data range provided in Examples 1-4 of this invention, it will not be described redundantly in order to reduce unnecessary repetition.
[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.
Claims
1. A method for preparing pre-transition metal oxide nanoparticles, characterized in that, A soluble pre-transition metal salt and ammonium chloride were selected and dissolved in a solvent, stirred thoroughly and sonicated, and heated and stirred to obtain a precursor. The precursor was then placed in a tube furnace and calcined in an inert gas atmosphere to finally obtain pre-transition metal oxide nanoparticles.
2. The method according to claim 1, characterized in that, The soluble pre-transition metal salts include any one or more of the following: scandium nitrate, scandium chloride, scandium acetylacetonate, zirconium oxychloride, zirconium oxynitrate, zirconium sulfate, zirconium acetate, zirconium acetylacetonate, hafnium dichloride, hafnium nitrate, hafnium sulfate, hafnium acetylacetonate, tungstic acid, ammonium tungstate, ammonium metatungstate, ammonium paratungstate, sodium tungstate, sodium metatungstate, sodium paratungstate, potassium tungstate, potassium metatungstate, potassium paratungstate, lithium tungstate, lithium metatungstate, and lithium paratungstate.
3. The method according to claim 1, characterized in that, The molar ratio of the soluble pre-transition metal salt to ammonium chloride is between 1:1 and 1:
50.
4. The method according to claim 1, characterized in that, The method of dissolving soluble pre-transition metal salts and ammonium chloride in 10-50 mL of water or ethanol also includes ultrasonic or stirring dissolution for 0.5-3 hours.
5. The method according to claim 1, characterized in that, The solvent is evaporated by using a magnetic heating stirrer, water bath, oil bath, or sand bath. The heating temperature is 80-120℃ and the heating time is 5-8 hours.
6. The method according to claim 1, characterized in that, The calcination atmosphere is argon or nitrogen, the calcination temperature is 300-1200℃, and the calcination time is 0.5-3 h.
7. A pre-transition metal oxide nanoparticle, characterized in that, The nanoparticles are obtained by any one of the methods of claims 1-6, and the particle size of the pre-transition metal oxide nanoparticles is 10-100 nm.
8. The application of the nanoparticles according to claim 7, characterized in that, The nanoparticles were used as a catalyst for the oxygen reduction synthesis of hydrogen peroxide.