Preparation method of metal oxide modified oxygen-rich vacancy conductive titanium oxide and application thereof

Abstract

The application discloses a preparation method and application of metal oxide modified oxygen vacancy-rich conductive titanium oxide, and when the metal oxide modified oxygen vacancy-rich conductive titanium oxide is used as an iridium-based supported oxygen electrode reaction catalyst carrier, an electronic synergistic effect is generated between oxygen vacancies in the carrier and iridium nanoparticles; the oxygen vacancies can activate originally inert titanium sites in the carrier, and provide electrons to the iridium nanoparticles through Ir-O-Ti bridging bonds; further, the introduction of metal oxide regulating components can adjust the local electronic structure and oxygen vacancy distribution of the carrier, enhance the stability of the defect structure under strong acidity and high oxidation potential conditions, and thus enhance the intrinsic catalytic activity and structural stability of the catalyst. Compared with a commercial iridium oxide supported catalyst, the catalyst prepared in the application can reduce the iridium consumption by more than 50% when reaching the same catalytic activity, significantly improve the utilization rate of noble metal atoms, and effectively reduce the noble metal consumption.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic materials technology, and relates to a method for preparing conductive titanium oxide and its application, specifically a method for preparing a metal oxide-modified, vacancy-rich conductive titanium oxide support and its application in oxygen electrode reactions. Background Technology

[0002] Proton exchange membrane electrolysis (PEMWE) and fuel cell technology, centered on the oxygen electrode reaction (OER, ORR), have become important research directions in the field of clean energy. However, this reaction still faces a series of problems that urgently need to be solved, such as high dependence on precious metal materials, slow oxygen evolution kinetics, and how to maintain long-term stability under operating conditions. To address these issues, supported catalysts using titanium dioxide as a carrier have become an important candidate system due to their low cost of raw materials, simple preparation, and excellent stability under acidic and high-potential conditions, and have already achieved some commercial applications. However, ordinary titanium dioxide has poor intrinsic conductivity (10... -12 ~ 10 -7 S·cm -1 Smaller specific surface area (<50 m²) 2 ·g -1 Defects such as these hinder the efficient dispersion of active components and the improvement of electron transport performance. To ensure catalyst performance, it is usually necessary to increase the loading of the noble metal Ir (≥60 wt%), which significantly increases the overall cost of the system and restricts the practical application of the technology. Therefore, there is an urgent need to prepare a catalyst that can maintain excellent stability under acidic and high potential (>1.5 V) conditions, while possessing improved conductivity and a large specific surface area (>100 m²). 2 ·g -1 The catalyst support material is of great significance for reducing the overall cost of this technology, improving catalytic performance, and promoting its practical application. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method for preparing conductive titanium oxide modified with metal oxide and oxygen-rich vacancies, and its application.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A method for preparing conductive titanium oxide modified with metal oxide and containing oxygen-rich vacancies includes the following two technical solutions:

[0006] Technical Solution 1

[0007] Step S1: Mix the titanium source and alcohol at a volume ratio of 1:1 to 1:5 to obtain mixture A; dissolve an acid of a certain concentration in the alcohol, add the metal source and mix thoroughly, with the mass ratio of the metal source to the titanium source being 1:1 to 100, to obtain mixture B; continuously add mixture B to mixture A until a distinct white gel appears, adjust the pH to 1 to 7, and obtain the titanium oxide precursor, which is then aged. The titanium source is selected from one of titanium tetrachloride, tetrabutyl titanate, titanium isopropoxide, and titanium sulfate; the alcohol is selected from isopropoxide... The mixture contains one of the following: alcohol, ethanol, and methanol; the acid-alcohol volume ratio in the mixture B is 1-3:2-9; the acid is selected from one of the following: sulfuric acid, hydrochloric acid, nitric acid, glacial acetic acid, hydrofluoric acid, citric acid, and ascorbic acid, with a concentration of 0.1M-1M; the metal source includes cerium acetate, cerium nitrate, lanthanum acetate, lanthanum nitrate, lanthanum chloride, neodymium nitrate, neodymium sulfate, neodymium acetate, neodymium oxalate, gadolinium acetate, samarium nitrate, samarium acetate, samarium oxalate, and similar rare earth metals or transition metal sources; the aging time is 8-12 h.

[0008] Step S2: Add a reducing agent to the titanium oxide precursor, the mass of the reducing agent being 0.1 wt%~20 wt% of the precursor mass, and stir evenly. Then calcine under an inert atmosphere (argon, nitrogen) or a weakly reducing atmosphere (Ar / N2 containing 5% H2) to obtain conductive titanium oxide. Afterward, acid washing is performed to remove excess reducing agent and soluble by-products. The reducing agent is at least one of urea, sodium borohydride, and magnesium powder. The calcination temperature is 400~850 ℃, the heating rate is 3~5 ℃ / min, and the holding time is 2~6 h. The acid washing uses at least one of hydrochloric acid, nitric acid, and sulfuric acid, the acid concentration is 1~3 M, and the acid washing time is 2~8 h.

[0009] Step S3: Process the conductive titanium oxide obtained in step S2 by pulverizing it to a particle size of 10 nm to 500 nm (preferably 50 to 200 nm), followed by filtration and drying to obtain metal oxide-modified oxygen-vacancy-rich conductive titanium oxide (TiO2). x (1 < x < 2), wherein: the pulverization method is ball milling or ultrafine pulverization, the ball milling time is 1~24 h, the ball milling speed is 500~2000 rpm, and the ball-to-material ratio is 25:1~4:1 (sample:ball); the gas pressure for ultrafine pulverization is 0.2~1.5 MPa, and the gas flow rate is 10~100 m³ / s. 3 / h, the crushing time is 30 min~12 h, and the classifying wheel speed is 500~3000 r / min;

[0010] Technical Solution 2

[0011] Step S1: Mix the titanium source and alcohol at a volume ratio of 1:1 to 1:5 to obtain mixture A; dissolve an acid of a certain concentration in the alcohol to obtain mixture B; continuously add mixture B to mixture A until a distinct white gel appears, adjust the pH to 1 to 7, obtain the titanium oxide precursor, and age it. The titanium source is selected from tetrabutyl titanate, titanium tetrachloride, titanium isopropoxide, tetraisopropanolamine titanate, and titanium oxysulfate; the alcohol is selected from methanol, ethanol, n-propanol, and isopropanol; the acid-alcohol volume ratio in mixture B is 1 to 3:2 to 9; the acid is selected from sulfuric acid, hydrochloric acid, nitric acid, glacial acetic acid, hydrofluoric acid, citric acid, and ascorbic acid, with a concentration of 0.1 M to 1 M; the aging time is 8 to 12 hours.

[0012] Step S2: Add a reducing agent to the titanium oxide precursor, the mass of the reducing agent being 0.1 wt%~20 wt% of the precursor mass, and stir evenly. Then calcine under an inert atmosphere (argon, nitrogen) or a weakly reducing atmosphere (Ar / N2 containing 5% H2). Afterward, acid washing is performed to remove excess reducing agent and soluble by-products to obtain conductive titanium oxide. The reducing agent is selected from at least one of urea, sodium borohydride, magnesium powder, aluminum powder, zinc powder, and hydrazine hydrate. The calcination temperature is 400~850 ℃, the heating rate is 3~5 ℃ / min, and the holding time is 2~6 h. The acid washing uses at least one of hydrochloric acid, nitric acid, and sulfuric acid, with an acid concentration of 1~3 M, and the acid washing time is 2~8 h.

[0013] Step S3: Add metal oxide nanoparticles (10 nm~1000 nm) to the conductive titanium oxide obtained in step S2, controlling the mass ratio of metal oxide to conductive titanium oxide to be 1:1~500; pulverize to a particle size of 10 nm~500 nm (preferably 50~200 nm), then filter and dry to obtain metal oxide modified oxygen-vacancy-rich conductive titanium oxide (TiO2). x (1 < x < 2, preferably 1.6 < x < 1.8), wherein: the metal oxide nanoparticles are one or more of lanthanum oxide, cerium oxide, nickel oxide, cobalt oxide, copper oxide, ruthenium oxide, iron oxide, and manganese oxide; the pulverization method is ball milling or ultrafine pulverization, the ball milling time is 1~24 h, the ball milling speed is 500~2000 rpm, and the ball-to-material ratio is 25:1~4:1 (sample:ball); the gas pressure for ultrafine pulverization is 0.2~1.5 MPa, and the gas flow rate is 10~100 m³ / h. 3 The crushing time is 30 min to 12 h, and the classifying wheel speed is 500 to 3000 r / min.

[0014] Application of metal oxide-modified oxygen-vacancy-rich conductive titanium dioxide prepared by the above method in an oxygen electrode reaction catalyst support.

[0015] An iridium-based supported oxygen electrode reaction catalyst includes a support and an active component supported on its surface, wherein: the support is conductive titanium oxide modified with the above-mentioned metal oxide and rich in oxygen vacancies; the active component is selected from one of iridium nanoparticles highly dispersed on the surface of the support, iridium oxide, and amorphous iridium oxide; the active component accounts for 0.01~50 wt% of the catalyst, preferably 5~40 wt%, more preferably 10~30 wt%; the particle size of the active component is 1~10 nm, preferably 2~5 nm.

[0016] A method for preparing the above-mentioned iridium-based supported oxygen electrode reaction catalyst includes the following steps:

[0017] Step S1: The carrier material and surfactant are uniformly dispersed in a solvent at a mass ratio of 1:5~50 to obtain solution A; simultaneously, the iridium source is dispersed in the same solvent to obtain solution B, wherein: the surfactant is selected from at least one of hexadecyltrimethylammonium bromide (CTAB), polyvinylpyrrolidone (PVP), and sodium hexadecyl sulfate (SDS); the iridium source is selected from one of chloroiridium acid, iridium acetylacetonate, iridium acetate, and iridium chloride hydrate, and the iridium source concentration is 1~5 mg / mL; the solvent is selected from at least one of methanol, ethanol, ethylene glycol, isopropanol, ammonia, and hydrazine hydrate; the dispersion method is stirring or ultrasonic dispersion.

[0018] Step S2: Mix solution A and solution B under stirring, and treat the mixture using a hydrothermal method or a reflux method, wherein: the hydrothermal time is 8~12 h and the temperature is 80~220 ℃; the reflux time is 3~5 h and the temperature is 120~180 ℃.

[0019] Step S3: Filtration and drying yield an iridium-based supported oxygen electrode reaction catalyst.

[0020] The above-mentioned iridium-based supported oxygen electrode reaction catalyst can be used in oxygen electrode reactions, specifically as an electrocatalyst for hydrogen production by water electrolysis, an oxygen reduction electrocatalyst for fuel cells, and an electrocatalyst for carbon dioxide reduction.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. This invention provides a method for preparing a metal oxide-modified oxygen-rich vacancy titanium oxide support, wherein titanium is present in the support as Ti. 4+ / T i3+ With mixed valence states present, the room temperature electronic conductivity increases to 10. -3 ~10 S·cm -1 Specific surface area reaches 80~200 m² 2 ·g -1Modification with metal oxides can form a tight heterogeneous interface, enhancing electron transport within the support and redistribution of interfacial charges. This titanium oxide support is simple to prepare (one-step reduction-calcination method), operates under mild conditions (atmospheric pressure, 400–700°C), is safe to operate (no high temperature, high pressure, or toxic gases), and has a yield >90%, making it suitable for large-scale preparation.

[0023] 2. After loading iridium nanoparticles, the oxygen vacancies (V) in the support O An electronic synergistic effect is generated between the iridium nanoparticles and the catalyst: oxygen vacancies can activate the originally inert titanium sites in the support and provide electrons to the iridium nanoparticles through Ir-O-Ti bridging bonds; furthermore, the introduction of metal oxide modulators can regulate the local electronic structure and oxygen vacancy distribution of the support, enhance the stability of the defect structure under strong acid and high oxidation potential conditions, thereby enhancing the intrinsic catalytic activity of the catalyst (mass activity increased to 1008 A / g). Ir The catalyst exhibits excellent catalytic activity (e.g., 10 mA / cm³) and structural stability (overpotential decay <5% after 100 h of continuous operation in 0.5 M H₂SO₄). Compared to commercially available iridium oxide supported catalysts, the catalyst prepared in this invention achieves the same catalytic activity (e.g., 10 mA / cm³). 2 When using iridium, the amount of iridium used is reduced by more than 50%, which significantly improves the utilization rate of precious metal atoms, effectively reduces the amount of precious metal used, and has better economic efficiency and application prospects. Attached Figure Description

[0024] Figure 1 A flowchart illustrating the preparation process of conductive titanium oxide modified with oxygen-rich vacancies using metal oxides.

[0025] Figure 2 The modified oxygen-rich vacancy titanium dioxide (La-TiO2) prepared in Example 1 x ) support and Ir / TiO x X-ray diffraction (XRD) patterns of the catalyst and commercial anatase TiO2 (Comparative Example 1).

[0026] Figure 3 The electron paramagnetic resonance (EPR) spectra of the modified oxygen-rich vacancy titanium dioxide prepared in Example 1 and the comparative example of commercial TiO2 are shown. The signal at a g-factor of approximately 2.003 confirms the presence of oxygen vacancies.

[0027] Figure 4 The image shows a scanning electron microscope (SEM) image of the modified oxygen-rich vacancy titanium oxide prepared in Example 1, which shows the morphology of small particle packing with a particle size distribution of 100~500 nm.

[0028] Figure 5The above are X-ray photoelectron spectroscopy (XPS) spectra of Ti 2p in titanium oxide prepared from commercial TiO2 in Examples 1 (argon calcination), Example 2 (air calcination), and Comparative Example 1, showing the Ti 2p content in the support of this invention. 3+ / Ti 4+ The existence of mixed valence states.

[0029] Figure 6 XPS measurements of Ir / La-TiOx in Example 1 and IrO2 in Comparative Example 2 show Ir 4f. 0 The presence of the peak and its shift to lower binding energies confirm the transfer of electrons from the carrier to Ir.

[0030] Figure 7 The linear sweep voltammetric polarization (LSV) curves of the catalysts prepared in Examples 1, 2, 3, and Comparative Example 2 under acidic conditions are shown.

[0031] Figure 8 The Tafel slope diagrams of the catalysts prepared in Examples 1, 2, 3, and Comparative Example 2 under acidic conditions are used to evaluate the OER reaction kinetics.

[0032] Figure 9 The Nyquist (EIS) plots of the catalysts prepared in Examples 1, 2, 3, and Comparative Example 2 under acidic conditions are used to evaluate the charge transfer resistance Rct. Detailed Implementation

[0033] The technical solution of the present invention will be further described below with reference to the accompanying drawings, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0034] Test equipment and methods:

[0035] XRD tests were performed on a PANalytical X Pert PRO XRD analyzer using Cu Kα rays at a wavelength of λ = 0.1542 nm and a scan rate of 5 ° / min.

[0036] SEM tests were performed on a Hitachi SU-8010 instrument.

[0037] Electrochemical performance tests were performed using a Shanghai Chenhua CHI760E electrochemical workstation in a three-electrode system. The LSV scan rate was 5 mV / s, and the test voltage range was 1.0–1.8 V. All electrode potentials in the polarization curves were manually corrected using iR compensation.

[0038] Example 1:

[0039] (1) Preparation of conductive titanium oxide with oxygen-rich vacancies modified by metal oxide (pre-doped):

[0040] Step S1: Measure 10 mL of tetrabutyl titanate and dissolve it in 15 mL of anhydrous ethanol to obtain solution A; prepare 12 mL of 1M hydrochloric acid, mix it with 8 mL of anhydrous ethanol, then add 0.1 g of lanthanum chloride and stir thoroughly to obtain solution B.

[0041] Step S2: Add solution B dropwise to solution A under magnetic stirring, adjust the pH to 4, and then seal and age the precursor for 12 h.

[0042] Step S3: Add 0.2 g of sodium borohydride to the precursor, stir evenly, and place it in a tube furnace. Set the atmosphere of the tube furnace to argon, the furnace temperature to 550℃, and increase the temperature to 550℃ at 3℃ / min. Hold the temperature for 4 h, and then cool it to room temperature with the furnace.

[0043] Step S4: After calcination, wash the sample thoroughly with 1M hydrochloric acid to remove excess reducing agent, and then vacuum dry at 60 °C for 12 h.

[0044] Step S5: Mix the sample obtained in step S4 with zirconia grinding balls at a mass ratio of 10:1 (sample:ball) and ball mill. Introduce argon gas at a flow rate of 150 mL / min, set the ball milling time to 2 h and the rotation speed to 500 rpm. Collect the sample after ball milling to obtain metal oxide modified oxygen-rich vacancy conductive titanium dioxide.

[0045] (2) Acidic OER supported catalyst (Ir / La-TiO) x Preparation of )

[0046] Step S1: Weigh 0.1 g of modified titanium dioxide carrier, 10 mg of CTAB, mix with 25 mL of ethylene glycol, and then ultrasonically disperse for 30 min (power 200 W) to achieve uniform dispersion.

[0047] Step S2: Add 5 mg / mL of chloroiridium acid in ethanol (theoretical Ir loading is 30 wt%) to the suspension obtained in step S1 and stir continuously for 2 h to allow IrCl4 to form. 2- After complete adsorption, the mixture was refluxed at 170 °C under nitrogen protection for 4 h, then cooled to room temperature, centrifuged at 8000 rpm for 5 min, washed three times with ethanol, and then dried under vacuum at 60 °C for 12 h to obtain Ir / La-TiO₂. x catalyst.

[0048] Example 2:

[0049] (1) Preparation of conductive titanium dioxide with oxygen-rich vacancies modified by metal oxide (ball milling):

[0050] Step S1: Measure 10 mL of tetrabutyl titanate and dissolve it in 15 mL of anhydrous ethanol to obtain solution A; prepare 12 mL of 1M hydrochloric acid and mix it with 8 mL of anhydrous ethanol to obtain solution B.

[0051] Step S2: Add solution B dropwise to solution A under magnetic stirring, adjust the pH to 4, and then seal and age the precursor for 12 h.

[0052] Step S3: Add 0.2 g of sodium borohydride to the precursor, stir evenly, and place it in a tube furnace. Set the atmosphere of the tube furnace to argon, the furnace temperature to 550℃, and increase the temperature to 550℃ at 3℃ / min. Hold the temperature for 4 h, and then cool it to room temperature with the furnace.

[0053] Step S4: After calcination, wash the sample thoroughly with 1M hydrochloric acid to remove excess reducing agent, and then vacuum dry at 60 °C for 12 h.

[0054] Step S5: Mix the sample obtained in step S4 with zirconia grinding balls at a mass ratio of 10:1 (sample:ball) and ball mill. Add 0.5 g of lanthanum nitrate and introduce argon gas at a flow rate of 150 mL / min. Set the ball milling time to 2 h and the rotation speed to 500 rpm. Collect the sample after ball milling to obtain metal oxide modified oxygen-rich vacancy conductive titanium dioxide.

[0055] (2) Preparation of acidic OER supported catalyst (Ir / La-TiOx): carried out according to Example 1.

[0056] Example 3:

[0057] (1) Preparation of oxygen-rich conductive titanium oxide: carried out according to Example 1.

[0058] (2) Preparation of acidic OER supported catalyst (Ir / La-TiOx): The difference from Example 1 is that the concentration of chloroiridium ethanol solution is 1 mg / mL, and other conditions are exactly the same as in Example 1, which is used to study the effect of Ir loading on catalytic performance.

[0059] Test Example 1:

[0060] Ir / La-TiO prepared in Example 1 was selected. x The catalyst slurry was prepared by adding 5 mg of catalyst, 60 μL of 5‰ Nafion perfluorinated sulfonate, and 2 mL of isopropanol. The glassy carbon electrode used had an area of ​​0.07 cm². 2Electrochemical tests for OER were performed using an electrochemical workstation. Linear sweep voltammetry (LSV) was conducted in a 0.5 M H2SO4 electrolyte solution, with a scan range of 1.0–1.8 V and a scan rate of 5 mV / s. Mercurous sulfate, platinum wire, and glassy carbon electrodes were used as the reference electrode, counter electrode, and working electrode, respectively.

[0061] Test Example 2:

[0062] The catalyst prepared in Example 2 was selected, and the conditions were kept the same as those in Test Example 1, except that the catalyst source was different.

[0063] Test Example 3:

[0064] The catalyst prepared in Example 3 was selected, and the conditions were kept the same as those in Test Example 1, except that the catalyst source was different.

[0065] Comparative Example 1:

[0066] Commercial anatase titanium dioxide (specific surface area ~50 m²) was used. 2 / g, anaerobic vacancies), other conditions are the same as in test example 1.

[0067] Comparative Example 2:

[0068] Commercial iridium dioxide (IrO2, Alfa, Ir content ≥85%) was used, and other conditions were kept the same as in Test Example 1.

[0069] Material structure and composition analysis:

[0070] Figure 2 The images show the X-ray diffraction patterns of the unmodified titanium dioxide and the metal oxide-modified support prepared in Example 1, and those of Comparative Example 1. Figure 2 It can be seen that the unmodified oxygen-rich vacancy titanium dioxide crystal phase prepared by calcination is anatase, similar to the commercial anatase titanium dioxide crystal phase; after predoping with lanthanum chloride, a new peak appears in the XRD of the sample, corresponding to La 0.66 TiO 2.993 (PDF: 00-026-0827) proves that the lanthanum source was successfully doped.

[0071] Figure 3 The electron paramagnetic resonance (EPR) spectra of Example 1 and Comparative Example 1 are shown. Figure 3 As can be seen, oxygen vacancies were successfully introduced into the prepared titanium oxide sample.

[0072] Figure 4 The image shown is a scanning electron microscope (SEM) image of the carrier obtained in Example 1. Figure 4 As can be seen, the sample exhibits a small particle accumulation pattern with a particle size distribution range of 100~500 nm.

[0073] Figure 5 The images show the Ti 2p spectra of titanium oxide prepared in Examples 1, 2, and Comparative Example 1. Figure 5 As can be seen from the data, in the titanium oxide sample, Ti is mainly composed of Ti... 4+ / Ti 3+ The presence of mixed valence states significantly improves the intrinsic electronic conductivity of the carrier.

[0074] Figure 6 The images show the XPS spectra of Ir 4f for the catalysts prepared in Examples 1, 2, and 2 (Comparative Example 2). Figure 6 As can be seen from Ir 0 The peak gradually increases, and Ir 0 The shift of the peak to a lower binding energy indicates that electrons are transferred to Ir through the Ir-O-Ti bridge, and the Ir element exists in the catalyst in the form of Ir nanoparticles.

[0075] Material performance testing:

[0076] Table 1 Performance Test Results

[0077]

[0078] From Table 1 and Figures 7-9 The results show that this catalyst uses oxygen-vacancy-rich titanium dioxide as a support, and by introducing metal oxides to regulate the composition, a metal oxide-titanium oxide heterostructure is constructed. Subsequently, iridium nanoparticles are further loaded to form an Ir / metal oxide / TiO₂ interface. x Multiphase synergistic catalytic structure.

[0079] Compared to ordinary titanium dioxide, this titanium-based support exhibits higher electronic conductivity and more abundant defect sites, which enhances the interaction between iridium nanoparticles and the support, promotes interfacial charge transfer, and inhibits the migration and aggregation of iridium nanoparticles during the oxygen electrode reaction. Furthermore, the introduction of metal oxide modulators can regulate the local electronic structure and oxygen vacancy distribution of oxygen-rich vacancy titanium dioxide, enhancing the stability of the defect structure under strong acid and high oxidation potential conditions.

[0080] In a preferred embodiment, the doping method and metal source are pre-doped lanthanum chloride. The doping introduces La... 3+ Species can modulate the Ti-O network structure during crystal phase formation. Due to La... 3+ With Ti 4+ Differences in ionic radius and valence state allow the introduction of La species to induce local structural distortions and charge redistribution in titanium dioxide, promoting the formation of oxygen vacancies and Ti. 3+The formation of defects enhances the electronic conductivity and defect density of the titanium-based support. Furthermore, the La-O-Ti interface and oxygen-rich vacancy structure serve as anchoring sites for iridium nanoparticles, strengthening the interaction between the nanoparticles and the support and inhibiting the migration, aggregation, and dissolution of iridium species during the oxygen electrode reaction. Simultaneously, the lanthanum-regulated titanium oxide support modulates the electronic structure of the iridium active centers, maintaining the iridium species in a suitable electronic state and optimizing the process. The adsorption strength of reaction intermediates such as O and OOH is increased, thereby simultaneously improving the activity, stability and utilization rate of the oxygen electrode reaction.

Claims

1. A method for preparing conductive titanium oxide modified with metal oxide and containing oxygen-rich vacancies, characterized in that... The method includes the following steps: Step S1: Mix the titanium source and alcohol at a volume ratio of 1:1 to 1:5 to obtain mixture A; dissolve the acid in the alcohol, add the metal source and mix thoroughly, the mass ratio of the metal source to the titanium source is 1:1 to 100, and the volume ratio of the acid to the alcohol is 1 to 3:2 to 9 to obtain mixture B; continuously add mixture B to mixture A, adjust the pH to 1 to 7, obtain the titanium oxide precursor and age it; Step S2: Add a reducing agent to the titanium oxide precursor. The amount of reducing agent added is 0.1~20 wt% of the precursor. Stir evenly and then calcine under an inert atmosphere or a weak reducing atmosphere to obtain conductive titanium oxide. Then, acid wash is performed to remove excess reducing agent and soluble by-products. Step S3: Process the conductive titanium oxide obtained in step S2 by pulverizing it to a particle size of 10 nm to 500 nm, followed by filtration and drying to obtain metal oxide-modified oxygen-vacancy-rich conductive titanium oxide TiO2. x , 1 < x < 2.

2. The method for preparing conductive titanium oxide modified with oxygen-rich vacancies by metal oxide according to claim 1, characterized in that... In step S1, the titanium source is selected from titanium tetrachloride, tetrabutyl titanate, titanium isopropoxide, and titanium sulfate; the alcohol is selected from isopropanol, ethanol, and methanol; the acid is selected from sulfuric acid, hydrochloric acid, nitric acid, glacial acetic acid, hydrofluoric acid, citric acid, and ascorbic acid, with a concentration of 0.1M to 1M; the metal source includes cerium acetate, cerium nitrate, lanthanum acetate, lanthanum nitrate, lanthanum chloride, neodymium nitrate, neodymium sulfate, neodymium acetate, neodymium oxalate, gadolinium acetate, samarium nitrate, samarium acetate, samarium oxalate, or rare earth metals or transition metal sources; the aging time is 8 to 12 h; in step S2, the reducing agent is at least one of urea, sodium borohydride, and magnesium powder; the calcination temperature is 400 to 850 ℃, the heating rate is 3 to 5 ℃ / min, and the holding time is 2 to 6 h; the pickling uses at least one of hydrochloric acid, nitric acid, and sulfuric acid, with an acid concentration of 1 to 3 M, and the pickling time is 2 to 8 h. h; In step S3, the pulverization method is ball milling or ultrafine pulverization, the ball milling time is 1~24 h, the ball milling speed is 500~2000 rpm, and the ball-to-material ratio is 25:1~4:1; the gas pressure for ultrafine pulverization is 0.2~1.5 MPa, and the gas flow rate is 10~100 m³ / h. 3 The crushing time is 30 min to 12 h, and the classifying wheel speed is 500 to 3000 r / min.

3. The application of a metal oxide-modified oxygen-vacancy-rich conductive titanium dioxide prepared by the method of any one of claims 1-2 in an oxygen electrode reaction catalyst support.

4. An iridium-based supported oxygen electrode reaction catalyst, comprising a support and an active component supported on its surface, characterized in that... The carrier is conductive titanium oxide modified with oxygen-rich vacancies by the method of any one of claims 1-2, and the active component is selected from iridium nanoparticles dispersed on the surface of the carrier, iridium oxide, and amorphous iridium oxide.

5. The application of the iridium-based supported oxygen electrode reaction catalyst of claim 4 in the oxygen electrode reaction.

6. A method for preparing conductive titanium oxide modified with metal oxide and containing oxygen-rich vacancies, characterized in that... The method includes the following steps: Step S1: Mix the titanium source and alcohol at a volume ratio of 1:1 to 1:5 to obtain a mixture A; dissolve the acid in the alcohol to obtain a mixture B, wherein the volume ratio of acid to alcohol in mixture B is 1 to 3: 2 to 9; continuously add mixture B to mixture A, adjust the pH to 1 to 7, obtain the titanium oxide precursor and age it. Step S2: Add a reducing agent to the titanium oxide precursor. The amount of reducing agent added is 0.1~20 wt% of the precursor. Stir evenly and then calcine under an inert atmosphere or a weak reducing atmosphere. After that, acid washing is performed to remove excess reducing agent and soluble by-products to obtain conductive titanium oxide. Step S3: Add metal oxide nanoparticles to the conductive titanium oxide obtained in step S2, controlling the mass ratio of metal oxide to conductive titanium oxide to be 1:1~500; pulverize to a particle size of 10 nm~500 nm, then filter and dry to obtain metal oxide modified oxygen-vacancy-rich conductive titanium oxide TiO. x , 1 < x < 2.

7. The method for preparing conductive titanium oxide modified with oxygen-rich vacancies by metal oxide according to claim 6, characterized in that... In step S1, the titanium source is selected from one of tetrabutyl titanate, titanium tetrachloride, titanium isopropoxide, tetraisopropanolamine titanate, and titanium oxysulfate; the alcohol is selected from one of methanol, ethanol, n-propanol, and isopropanol; the acid is selected from one of sulfuric acid, hydrochloric acid, nitric acid, glacial acetic acid, hydrofluoric acid, citric acid, and ascorbic acid, with a concentration of 0.1M to 1M; the aging time is 8 to 12 h. In step S2, the reducing agent is selected from at least one of urea, sodium borohydride, magnesium powder, aluminum powder, zinc powder, and hydrazine hydrate; the calcination temperature is 400 to 850 ℃, the heating rate is 3 to 5 ℃ / min, and the holding time is 2 to 6 h; the acid washing uses at least one of hydrochloric acid, nitric acid, and sulfuric acid, with an acid concentration of 1 to 3 M, and the acid washing time is 2 to 8 h. In step S3, the particle size of the metal oxide nanoparticles is 10 nm to 1000 nm. nm; the metal oxide nanoparticles are one or more of lanthanum oxide, cerium oxide, nickel oxide, cobalt oxide, copper oxide, ruthenium oxide, iron oxide, and manganese oxide; the pulverization method is ball milling or ultrafine pulverization, the ball milling time is 1~24 h, the ball milling speed is 500~2000 rpm, and the ball-to-material ratio is 25:1~4:1; the gas pressure for ultrafine pulverization is 0.2~1.5 MPa, and the gas flow rate is 10~100 m³ / h. 3 The crushing time is 30 min to 12 h, and the classifying wheel speed is 500 to 3000 r / min.

8. The application of a metal oxide-modified oxygen-vacancy-rich conductive titanium dioxide prepared by the method of any one of claims 6-7 in an oxygen electrode reaction catalyst support.

9. An iridium-based supported oxygen electrode reaction catalyst, comprising a support and an active component supported on its surface, characterized in that... The carrier is conductive titanium dioxide with oxygen-rich vacancies modified by metal oxide prepared by the method of any one of claims 6-7, and the active component is selected from iridium nanoparticles dispersed on the surface of the carrier, iridium oxide, and amorphous iridium oxide.

10. The application of the iridium-based supported oxygen electrode reaction catalyst of claim 9 in the oxygen electrode reaction.

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