Fluorine-doped titanium-based gas diffusion electrode with lattice distortion, method of preparation and use thereof

Abstract

The application discloses a fluorine-doped titanium-based gas diffusion electrode with lattice distortion, a preparation method and application thereof, and the electrode material is a fluorine-doped titanium oxide electrode material, has a titanium-oxygen octahedral cell distortion structure, and the size of the electrode material is 20-50 nm; the electrode material is loaded on a carbon base and is treated to obtain a gas diffusion electrode. When the electrode is applied to a cathode of an electrolytic cell, excellent electrocatalytic reduction synthesis of hydrogen peroxide in an acid and alkali electrolyte is exhibited, the distortion degree of the titanium dioxide octahedron in the electrode can be adjusted by adjusting experimental parameters, the resistance of the electrode to the strong acid and strong alkali electrolyte is strengthened, the gas mass transfer efficiency and oxygen utilization rate are extremely high, and the high energy loss of the electrode caused by the pH of the electrolyte is avoided.

Description

Technical Field

[0001] This invention relates to a titanium-based gas diffusion electrode, belonging to the field of electrode fabrication technology. Background Technology

[0002] Hydrogen peroxide (H2O2) is not only a valuable oxidant in various chemical processes, but also a clean fuel with an energy density comparable to hydrogen. It also holds great promise for applications including chemical synthesis, water treatment, pulp / paper bleaching, aircraft propulsion, and disinfection. Due to the rapidly growing demand for hydrogen peroxide, annual production reached 9.07 million tons in 2017 and is projected to reach 13.5 million tons by 2022. The industrial production method for hydrogen peroxide typically employs the anthraquinone process, but the industrial-scale production of H2O2 using the anthraquinone process is extremely energy-intensive and involves multiple steps, large consumption of organic solvents, significant waste release, and explosion hazards. Therefore, the question of how to produce hydrogen peroxide in a "green" manner has attracted increasing attention. In the 1930s, Berl first reported the electrochemical production of H2O2 using the anthraquinone process. - Small-scale on-site H2O2 production route: oxygen reduction reaction (2e) - ORR, O2+2H + +2e - →H2O2), further developed by Dow and Huron Technologies, Inc., and commercialized in 1991. Since then, the electrochemical H2O2 production strategy has attracted increasing research interest as a potential alternative to the traditional anthraquinone redox process.

[0003] To the best of our knowledge, currently all reports of 2e - ORR catalysts fail to maintain excellent activity when pH is changed; therefore, developing novel pH-tolerant catalysts is crucial for addressing 2e⁻. - The large-scale practical application of ORR is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a titanium-based gas diffusion electrode material, its preparation method, and its application in the rapid electrocatalytic reduction of oxygen to hydrogen peroxide in strong bases and strong acids.

[0005] The technical solution to achieve the purpose of this invention is as follows:

[0006] A sub-nanometer titanium-based cell-twisted gas diffusion electrode material and its preparation method include the following steps:

[0007] Step 1: Dissolve ammonium fluoride and concentrated hydrochloric acid in ethanol and stir to form a homogeneous mixed solution;

[0008] Step 2: Add tetraisopropyl titanate to the mixed solution obtained in Step 1 and stir to form a homogeneous mixed solution;

[0009] Step 3: Place the solution obtained in Step 2 in a closed environment for hydrothermal reaction for a period of time, and then centrifuge and freeze dry to obtain titanium-based gas diffusion electrode material.

[0010] Furthermore, the molar ratio of tetraisopropyl titanate, ammonium fluoride, and concentrated hydrochloric acid is 0.005–0.05:0.0055–0.055:0.001–0.01.

[0011] Furthermore, in step three, the hydrothermal reaction temperature is 100-300℃, and the reaction time is 20-50h.

[0012] This invention provides a sub-nanometer titanium-based cell-twisted gas diffusion electrode material, which is a fluorine-doped titanium oxide electrode material with a titanium-oxygen octahedral cell-twisted structure and a size of 20-50 nm.

[0013] In addition, the present invention also provides a gas diffusion electrode based on the above-mentioned electrode material. The electrode material, binder Nafion and conductive agent carbon black are dispersed evenly in isopropanol to prepare a catalyst dispersion, which is then dropped onto a carbon substrate and allowed to dry naturally; and then assembled with a polytetrafluoroethylene film to form a gas diffusion electrode.

[0014] Finally, the present invention also provides the use of a sub-nanometer titanium-based cell-twisted gas diffusion electrode as a catalyst for the electrocatalytic reduction of oxygen to hydrogen peroxide in strong acid and strong base electrolytes.

[0015] Compared with the prior art, the advantages of this invention are: (1) The electrode is composed of sub-nanometer titanium-based cell-twisted material to form an oxygen diffusion electrode, which is simple to prepare and can be mass-produced industrially; (2) This material is conducive to the exposure of more active sites, providing abundant active sites; (3) It improves the tolerance to electrolytes with different pH values, eliminating the need for electrolyte acidity or alkaliness for electrocatalytic reduction under specific conditions; (4) The current density is close to the ampere level (1000 mA / cm²) under electrolyte pH = 1 to 13 conditions. -2 The Faraday efficiency of hydrogen peroxide production by oxygen electrolysis can still be maintained at around 90%, which has broad application prospects. Attached Figure Description

[0016] Figure 1 (a) is a schematic diagram of the assembly of the sub-nanometer titanium-based unit cell twisted gas diffusion electrode in this invention. Figure 1 Image (b) shows a physical picture of the gas diffusion electrode assembled into the electrolytic cell.

[0017] Figure 2These are TEM images of Example 1 of the present invention, wherein (a) is the overall morphology of the particles in Example 1, (b) is a high-resolution TEM partial image of Example 1, (c) is a partial lattice stripe image of Example 1, and (d) is a partial lattice stripe image of Example 1.

[0018] Figure 3 The present invention includes the lattice distortion sites marked in the high-resolution TEM image of Example 1 (a) and the lattice site size measurement (b).

[0019] Figure 4 In the image, (a) is the full X-ray photoelectron spectroscopy (XPS) image of Example 1 and Comparative Example 1 of the present invention, (b) is the 2p characteristic spectrum of Ti element of Example 1 and Comparative Example 1 of the present invention, (c) is the 1s characteristic spectrum of O element of Example 1 and Comparative Example 1 of the present invention, and (d) is the 1s characteristic spectrum of F element of Example 1 of the present invention.

[0020] Figure 5 In the figures, (a) is the X-ray diffraction pattern (XRD) of Comparative Example 1 of the present invention, and (b) is the X-ray diffraction pattern (XRD) of Example 1 of the present invention.

[0021] Figure 6 In the figures, (a) is the electron paramagnetic resonance (EPR) spectrum of Comparative Example 1 and Example 1 of the present invention, and (b) is the solid-state ultraviolet-visual spectrum (UV-Vis) of Comparative Example 1 and Example 1 of the present invention.

[0022] Figure 7 (a) shows the CV polarization curves of Example 1 and Comparative Example 1 in an H-type electrolytic cell in oxygen, with the inset showing the LSV polarization curves. (b) shows the CV polarization curves of Example 1 in argon and oxygen, with the inset showing the LSV polarization curves.

[0023] Figure 8 These are RRDE data plots for Comparative Example 1 and Example 1 of the present invention, showing selectivity (a) and the number of transferred electrons (b).

[0024] Figure 9 The UV absorbance curve of the colorimetric hydrogen peroxide in Comparative Example 1 of this invention (a) shows that the potential / product concentration increases with increasing current density gradient. (b) shows the potential change graph of Example 1 under constant current testing at 100-1000 mA cm⁻².

[0025] Figure 10 In the diagram, (a) is the Faraday efficiency (FE) diagram of the full pH electrolyte of Comparative Example 1 of the present invention, and (b) is the Faraday efficiency (FE) diagram of the full pH electrolyte of Example 1 of the present invention.

[0026] Figure 11The above describes the stability test of the full pH electrolyte in Example 1 of this invention.

[0027] Figure 12 In the diagram, (a) is a graph showing the Faradaic efficiency and yield of the neutral electrolyte of Comparative Example 1 of the present invention, (b) is a graph showing the Faradaic efficiency and yield of the neutral electrolyte of Example 2 of the present invention, (c) is a graph showing the Faradaic efficiency and yield of the neutral electrolyte of Example 3 of the present invention, (d) is a graph showing the Faradaic efficiency and yield of the neutral electrolyte of Example 4 of the present invention, (e) is a graph showing the Faradaic efficiency and yield of the neutral electrolyte of Example 5 of the present invention, and (f) is a graph showing the Faradaic efficiency and yield of the neutral electrolyte of Example 6 of the present invention.

[0028] Figure 13 In the diagram, (a) is the impedance diagram (EIS) of Embodiment 2 of the present invention, (b) is the impedance diagram (EIS) of Embodiment 3 of the present invention, (c) is the impedance diagram (EIS) of Embodiment 1 and Comparative Example 1 of the present invention, (d) is the impedance diagram (EIS) of Embodiment 4 of the present invention, (e) is the impedance diagram (EIS) of Embodiment 5 of the present invention, and (f) is the impedance diagram (EIS) of Embodiment 6 of the present invention.

[0029] Figure 14 The following are data graphs showing the economic analysis of Example 1 of the present invention in oxygen: (a) shows the cost of producing hydrogen peroxide in oxygen in Example 1 of the present invention and Comparative Example 1; (b) shows the cost of producing hydrogen peroxide in oxygen in Example 1 of the present invention using electrolytes with different pH values; (c) shows the cost percentage of Example 1 of the present invention in oxygen; (d) shows the single-factor analysis of Example 1 of the present invention in oxygen; and (e) shows the comparative analysis of the cumulative net present value of producing hydrogen peroxide in oxygen in Example 1 of the present invention and Comparative Example 1.

[0030] Figure 15 This is a schematic diagram illustrating the synthesis process and principle of the sub-nanometer titanium-based cell-twisted gas diffusion electrode material described in this invention. Detailed Implementation

[0031] Combination Figure 15 To improve the 2e-ORR performance of TiO2, we first doped it with non-metallic elements such as P, S, and Se, but the performance did not improve significantly. Then we doped it with F and surprisingly found that the strong electronegativity of F caused the Ti charge in TiO2 to be plundered by F, which led to an increase in the adsorption capacity of Ti sites for the 2e-ORR intermediate OOH. This increased the 2e-ORR performance and made it more resistant to acids and alkalis. Furthermore, the F doping caused the Ti-O octahedral cell to be distorted, which further enhanced the acid and alkali resistance of the already stable titanium dioxide metal oxide.

[0032] This invention is illustrated by the following examples, but these examples are for illustrative purposes only and should not be construed as limiting the scope or application of the invention. Unless otherwise specified, all materials used in this invention are commercially available.

[0033] Example 1:

[0034] Step 1: Dissolve 411 mg of ammonium fluoride and 0.732 mL of concentrated hydrochloric acid in 56 mL of ethanol and stir for 30 minutes to form a homogeneous mixed solution;

[0035] Step 2: Add 1.517 mL of tetraisopropyl titanate to the mixed solution obtained in Step 1 and stir for another 2 hours to form a homogeneous mixed solution;

[0036] Step 3: The solution obtained in Step 2 was placed in a closed environment and reacted at 150°C for 48 hours. After centrifugation and freeze-drying, titanium-based gas diffusion electrode material was obtained. Its XPS quantitative analysis is shown in Table 1.

[0037] Step 4: Combine the sub-nanometer titanium-based cell-twisted catalytic material obtained in Step 3 with Nafion, carbon black, carbon substrate, and polytetrafluoroethylene film to form a sub-nanometer titanium-based cell-twisted gas diffusion electrode.

[0038] Example 2:

[0039] Step 1: Dissolve 137 mg ammonium fluoride and 0.244 mL concentrated hydrochloric acid in 56 mL ethanol and stir for 30 minutes to form a homogeneous solution;

[0040] Step 2: Add 1.517 mL of tetraisopropyl titanate to the mixed solution obtained in Step 1 and stir for another 2 hours to form a homogeneous mixed solution;

[0041] Step 3: The solution obtained in Step 2 was placed in a sealed environment and reacted at 150°C for 48 hours. After centrifugation and freeze-drying, titanium-based gas diffusion electrode material was obtained.

[0042] Step 4: Combine the sub-nanometer titanium-based cell-twisted catalytic material obtained in Step 3 with Nafion, carbon black, carbon substrate, and polytetrafluoroethylene film to form a sub-nanometer titanium-based cell-twisted gas diffusion electrode.

[0043] Example 3:

[0044] Step 1: Dissolve 274 mg of ammonium fluoride and 0.488 mL of concentrated hydrochloric acid in 56 mL of ethanol and stir for 30 minutes to form a homogeneous mixture.

[0045] Step 2: Add 1.517 mL of tetraisopropyl titanate to the mixed solution obtained in Step 1 and stir for another 2 hours to form a homogeneous mixed solution;

[0046] Step 3: The solution obtained in Step 2 was placed in a sealed environment and reacted at 150°C for 48 hours. After centrifugation and freeze-drying, titanium-based gas diffusion electrode material was obtained.

[0047] Step 4: Combine the sub-nanometer titanium-based cell-twisted catalytic material obtained in Step 3 with Nafion, carbon black, carbon substrate, and polytetrafluoroethylene film to form a sub-nanometer titanium-based cell-twisted gas diffusion electrode.

[0048] Example 4:

[0049] Step 1: Dissolve 548 mg of ammonium fluoride and 0.976 mL of concentrated hydrochloric acid in 56 mL of ethanol and stir for 30 minutes to form a homogeneous mixed solution;

[0050] Step 2: Add 1.517 mL of tetraisopropyl titanate to the mixed solution obtained in Step 1 and stir for another 2 hours to form a homogeneous mixed solution;

[0051] Step 3: The solution obtained in Step 2 was placed in a sealed environment and reacted at 150°C for 48 hours. After centrifugation and freeze-drying, titanium-based gas diffusion electrode material was obtained.

[0052] Step 4: Combine the sub-nanometer titanium-based cell-twisted catalytic material obtained in Step 3 with Nafion, carbon black, carbon substrate, and polytetrafluoroethylene film to form a sub-nanometer titanium-based cell-twisted gas diffusion electrode.

[0053] Example 5:

[0054] Step 1: Dissolve 685 mg of ammonium fluoride and 1.22 mL of concentrated hydrochloric acid in 56 mL of ethanol and stir for 30 minutes to form a homogeneous mixture.

[0055] Step 2: Add 1.517 mL of tetraisopropyl titanate to the mixed solution obtained in Step 1 and stir for another 2 hours to form a homogeneous mixed solution;

[0056] Step 3: The solution obtained in Step 2 was placed in a sealed environment and reacted at 150°C for 48 hours. After centrifugation and freeze-drying, titanium-based gas diffusion electrode material was obtained.

[0057] Step 4: Combine the sub-nanometer titanium-based cell-twisted catalytic material obtained in Step 3 with Nafion, carbon black, carbon substrate, and polytetrafluoroethylene film to form a sub-nanometer titanium-based cell-twisted gas diffusion electrode.

[0058] Example 6:

[0059] Step 1: Dissolve 822 mg of ammonium fluoride and 1.464 mL of concentrated hydrochloric acid in 56 mL of ethanol and stir for 30 minutes to form a homogeneous mixture.

[0060] Step 2: Add 1.517 mL of tetraisopropyl titanate to the mixed solution obtained in Step 1 and stir for another 2 hours to form a homogeneous mixed solution;

[0061] Step 3: The solution obtained in Step 2 was placed in a sealed environment and reacted at 150°C for 48 hours. After centrifugation and freeze-drying, titanium-based gas diffusion electrode material was obtained.

[0062] Step 4: Combine the sub-nanometer titanium-based cell-twisted catalytic material obtained in Step 3 with Nafion, carbon black, carbon substrate, and polytetrafluoroethylene film to form a sub-nanometer titanium-based cell-twisted gas diffusion electrode.

[0063] Comparative Example 1:

[0064] Step 1: Add 1.517 mL of tetraisopropyl titanate to 56 mL of ethanol and stir for 30 minutes to form a homogeneous mixture.

[0065] Step 2: The solution obtained in Step 1 was placed in a closed environment and reacted at 150°C for 48 hours. After centrifugation and freeze-drying, titanium-based gas diffusion electrode material was obtained. Its XPS quantitative analysis is shown in Table 1.

[0066] Step 3: Combine the sub-nanometer titanium-based cell-twisted catalytic material obtained in Step 2 with Nafion, carbon black, carbon substrate, and polytetrafluoroethylene film to form a sub-nanometer titanium-based cell-twisted gas diffusion electrode.

[0067] Table 1 shows the atomic content of Example 1 and Comparative Example 1 in XPS quantitative analysis.

[0068]

[0069] Figure 1 (a) is a schematic diagram of the assembly of the sub-nanometer titanium-based cell twisted gas diffusion electrode in this invention. The catalyst material is loaded on the hydrophobic side of the carbon substrate to form a gas diffusion electrode, which is assembled into the electrolytic cell to become the cathode. The cathode and anode are separated by a cation membrane. Figure 1 Image (b) shows a physical picture of the gas diffusion electrode assembled into the electrolytic cell.

[0070] Comparative Example 1 TEM image as follows Figure 2 As shown in (a) of Example 1, Figure 2 Compared to (b) in Example 1, the overall morphology of the material did not change significantly, and Example 1 basically retained the particle size of Comparative Example 1. When the local area of ​​the material was further magnified, the high-resolution TEM of Comparative Example 1 showed... Figure 2 (c) shows that the nanoparticles have a well-defined interplanar spacing of 0.234 nm, which corresponds to the (100) plane of TiOF2. Figure 2 The figure shows that the interplanar spacing of the nanoparticles is 0.273 nm, which corresponds to the (110) crystal plane of the rutile phase TiO2.

[0071] To further determine the specific doping characteristics of Example 1, we further magnified the high-resolution TEM image and found dislocation fracture in the lattice fringes of the material in Example 1. We also... Figure 2 Further observation can be made by magnifying the localized lattice fringe distortion sites in (c) of the image. Figure 3 In (a), the cell distortions at two locations are clearly indicated and their dimensions are measured, as shown in [example image]. Figure 3 (b) We found that the size of the cell twist reaches the sub-nanometer scale of about 0.2 nm.

[0072] Figure 4 The XPS measurement spectrum of Comparative Example 1 (a) mainly consists of Ti and O peaks, while the XPS measurement spectrum of Example 1 mainly consists of Ti, F and O peaks. Figure 4 The (b)O 1s XPS spectrum in Example 1 shows a main peak at 529.7 eV, corresponding to lattice oxygen (Ti-O) in Comparative Example 1. Interestingly, a small peak at 533.0 eV, attributed to surface hydroxyl groups (Ti-OH), appears in Example 1. Since oxygen vacancies on the surface are filled by reacting with H₂O in the air, these oxygen vacancies induce the dissociation of water molecules and their dissociation via H₂O. + Two hydroxyl groups are formed by transferring oxygen to an adjacent lattice. Figure 4 In (c) the high-resolution Ti 2p XPS spectrum, the two peaks at 458.5 and 464.2 eV correspond to Ti 2p, respectively. 3 / 2 and Ti 2p 1 / 2 After F doping, Ti 2p 3 / 2 Peaks and Ti 2p 1 / 2 The peak shifts towards smaller bond energies, indicating the presence of Ti. 3+ Species. Figure 4 The F1s XPS spectrum of (d) after F-doping TiO2 is decomposed into two peaks: the peak at 684.7 eV corresponds to surface F ions, and the peak at 686.1 eV belongs to substituted F ions in the F-TiO2 lattice, which is consistent with the reported value of bulk F ions in the TiO2 lattice.

[0073] Furthermore, based on the characteristic peaks of Ti, O, and F elements in the XPS spectra, we performed elemental analysis on Example 1 and Comparative Example 1, and the elemental atom proportions are shown in Table 1. The presence of F atoms in Example 1 indicates successful doping with F atoms, which replaced some O atoms, creating oxygen vacancies. Combined with TEM data, this shows that while the introduction of abundant F atoms in Example 1 caused lattice distortion, it did not lead to drastic changes in the crystal structure.

[0074] Figure 5Further X-ray diffraction (XRD) analysis was conducted on the crystal structures of Example 1 and Comparative Example 1, revealing differences in peak positions. Comparison showed that Example 1 had an increased number of crystal planes, indicating that F doping caused significant changes in the crystal.

[0075] Figure 6 Figure (a) shows the electron paramagnetic resonance (EPR) spectra of Example 1 and Comparative Example 1. It is clear that the EPR signal of the material in Example 1 at g = 2.003 is significantly different from that in Comparative Example 1, proving the presence of oxygen vacancies in Example 1. Figure 6 Figure (b) shows the UV-Vis absorption spectra of the prepared Sample 1 and Comparative Example 1. It can be clearly seen that Comparative Example 1 exhibits significantly enhanced light absorption in the visible region. The strong visible light absorption is attributed to the presence of oxygen vacancies, which can induce continuous donor levels in electronic states below the conduction band, consistent with the conclusions drawn by XPS and EPR.

[0076] Figure 7 As shown in (a), the electrochemical performance of the ORR of the relevant materials in Example 1 is compared with that of Comparative Example 1. Example 1 exhibits a higher reduction potential, but the current density does not change significantly, indicating that the material in Example 1 has a larger electrochemical active area and abundant active sites. This is because the F doping in the material of Example 1 induces oxygen vacancies to achieve efficient ORR utilization through oxygen polarization. Furthermore, through... Figure 3 As shown in the small figure, the reduction peaks of the materials in Comparative Example 1 and Example 1 are both around 0.35V. However, the current density of Example 1 is slightly higher than that of Comparative Example 1. This also indicates that the material in Example 1 has a larger electrochemical active area and abundant active sites. Figure 7 In (b) of the diagram, the CV curve shows a reduction peak at 0.31 V vs. RHE in the oxygen-saturated electrolyte. This reduction peak disappears when the electrolyte is replaced with an argon-saturated electrolyte, indicating that oxygen in the electrolyte undergoes a reduction reaction under the corresponding voltage conditions. Furthermore, comparing the LSV values ​​of the reactions under O2 and Ar2 conditions in the inset shows a reduction peak at 0.35 V vs. RHE in the oxygen-saturated electrolyte. This also confirms that oxygen in the electrolyte undergoes a reduction reaction under the corresponding voltage conditions, and this reduction peak is an oxygen reduction peak.

[0077] Figure 8 As shown in (a) by the RRDE method, the selectivity of Example 1 in the voltage range of -0.2 to 0.2 V is about 80%, while the selectivity of Comparative Example 1 drops sharply from 60% to 3% in the same voltage range. This also proves that the two-electron oxygen reduction efficiency of Comparative Example 1 is much lower than that of Example 1. Figure 7In example (b), within the voltage range of -0.2 to 0.2 V, the number of electrons transferred is approximately 2.3, indicating that the reaction process in electrocatalytic oxygen reduction is more inclined towards a two-electron reaction. Comparative Example 1 shows that the number of transferred electrons within the voltage range of -0.2 to 0.2 V is approximately 3. This demonstrates that the oxygen reduction efficiency of Comparative Example 1 is significantly lower than that of Example 1 within this reaction potential range of -0.2 to 0.2 V.

[0078] Figure 9 In (a) after constant potential test, the cathode electrolyte is taken out for color reaction and ultraviolet test. The ultraviolet spectra of different materials are shown. The absorbance peak is at 408nm. The material in Example 1 has the highest absorbance, that is, the hydrogen peroxide concentration in its corresponding electrolyte is the highest. Figure 9 (b) shows the chronoamperometry test (5 min) of the material in Example 1 at different voltages and the chronoamperometry test of different materials at the same voltage. As the current density changes, the voltage also changes, which is consistent with the general law of ORR. During the 5-minute test, the voltage fluctuated within a small range, which is due to the disturbance caused by the continuous introduction of oxygen into the electrolyte to the electrochemical test system, and is a normal phenomenon. The current density remained basically stable over a large range without significant attenuation; therefore, the test results have stable reference value. When the current density is -1000 mA / cm²... -2 At the specified potential, hydrogen peroxide yield was highest, and the relationship between hydrogen peroxide yield and current density was basically consistent for different materials. Among the various materials tested, the material in Example 1 exhibited the best performance across all tested potentials.

[0079] Figure 10 (a) in the figure shows the Faraday efficiency of the ORR test in electrolytes of Comparative Example 1 at different pH values. The Faraday efficiency gradually decreases with increasing current. Figure 10 (b) is a Faraday efficiency graph of ORR test in electrolytes of Example 1 at different pH values. As can be seen from the graph, the Faraday efficiency does not decrease with the change of electrolyte pH and remains above 90%, which proves that the oxygen reduction performance of Example 1 is not affected by the change of electrolyte pH.

[0080] Figure 11 The results show that Example 1 can work stably for more than 50 hours in long-term stability tests.

[0081] Figure 12(a) is the Faraday efficiency and yield graph of Comparative Example 1 in neutral electrolyte; (b) is the Faraday efficiency and yield graph of Example 2 in neutral electrolyte; (c) is the Faraday efficiency and yield graph of Example 3 in neutral electrolyte; (d) is the Faraday efficiency and yield graph of Example 4 in neutral electrolyte; (e) is the Faraday efficiency and yield graph of Example 5 in neutral electrolyte; and (f) is the Faraday efficiency and yield graph of Example 6 in neutral electrolyte. The Faraday efficiency decreases with increasing current density, indicating that Comparative Example 1, Example 2, Example 3, and Example 4 are not resistant to high currents.

[0082] Figure 13 (a) is the impedance diagram (EIS) of Example 2; (b) is the impedance diagram (EIS) of Example 3; (c) is the impedance diagram (EIS) of Comparative Example 1 and Example 1; (d) is the impedance diagram (EIS) of Example 4; (e) is the impedance diagram (EIS) of Example 5; and (f) is the impedance diagram (EIS) of Example 6. Among them, the impedance of Example 4 is the largest at 150Ω, while the others are all around 50Ω.

[0083] Figure 14 The following is an economic analysis of hydrogen peroxide production in oxygen in Example 1. (a) shows a cost comparison analysis between Example 1 and Comparative Example 1 in oxygen production. The higher the current density, the lower the production cost of Example 1 in oxygen, and it is consistently lower than the production cost of the Comparative Example in oxygen. (b) A cost comparison analysis of hydrogen peroxide production in oxygen with different pH electrolytes in Example 1 shows that the cost of hydrogen peroxide production does not increase significantly with changes in electrolyte pH. (c) The cost percentage of Example 1 in oxygen. (d) A single-factor analysis of Example 1 in oxygen. (e) A cumulative net present value analysis of electrolysis in oxygen for Example 1 and Comparative Example 1. The data shows that as time increases, the profit gap between Example 1 and Comparative Example 1 gradually widens, and the advantages of electrolysis in Example 1 become increasingly prominent.

Claims

1. A method for preparing a sub-nanometer titanium-based crystalline cell distorted gas diffusion electrode material, characterized in that, The method comprises the following steps: Step 1: Dissolve ammonium fluoride and concentrated hydrochloric acid in ethanol to form a uniform mixed solution; Step 2: Add titanium isopropyl to the mixed solution obtained in step 1 and stir to form a uniform mixed solution; Step 3: Place the solution obtained in step 2 in a sealed environment and hydrothermally react for a period of time, then centrifuge and freeze-dry to obtain a titanium-based gas diffusion electrode material.

2. The method of claim 1, wherein, The molar ratio of titanium isopropyl, ammonium fluoride and concentrated hydrochloric acid is 0.005-0.05:0.0055-0.055:0.001-0.

01.

3. The method of claim 1, wherein, In step 3, the hydrothermal reaction temperature is 100-300 ℃ and the reaction time is 20-50 h.

4. A sub-nanometer titanium-based crystal cell distorted gas diffusion electrode material prepared by the method of any one of claims 1-3.

5. The electrode material of claim 4, wherein, The electrode material is a fluorine-doped titanium oxide electrode material with a titanium-oxygen octahedral cell distorted structure, and the size of the electrode material is 20-50 nm.

6. A gas diffusion electrode based on the electrode material of claim 4 or 5, characterized in that After dispersing the electrode material, the adhesive Nafion and the conductive agent carbon black with isopropyl alcohol, drop them onto the carbon base and dry naturally; then assemble them with a polytetrafluoroethylene film to form a gas diffusion electrode.

7. Use of the gas diffusion electrode of claim 6 as a catalyst for electrocatalytic oxygen reduction to synthesize hydrogen peroxide in a strong acid and strong base electrolyte.

8. An oxygen electrolysis cell characterized in that, It comprises the gas diffusion electrode of claim 6.

7. Use of the gas diffusion electrode of claim 6 as a catalyst for electrocatalytic oxygen reduction to synthesize hydrogen peroxide in a strong acid and strong base electrolyte. It comprises the gas diffusion electrode of claim 6.

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