A transition metal-doped titanium dioxide catalyst, a preparation method and use thereof, and an apparatus for producing hydrogen peroxide through electrochemical water oxidation
By using a transition metal-doped titanium dioxide catalyst, the problems of insufficient selectivity and activity in hydrogen peroxide production in existing technologies have been solved, and efficient electrochemical water oxidation to produce hydrogen peroxide with high selectivity and high yield has been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING UNIV OF CHEM TECH
- Filing Date
- 2022-09-13
- Publication Date
- 2026-06-26
AI Technical Summary
In existing technologies, transition metal compounds are generally used for electrocatalytic water production of oxygen, rather than hydrogen peroxide. Furthermore, titanium dioxide has poor performance in electrochemical water oxidation to produce hydrogen peroxide, making it difficult to achieve high selectivity and high activity.
A titanium dioxide catalyst doped with transition metals (such as ruthenium, nickel, iron, cobalt, manganese, and palladium) exists in a MO-Ti coordination form with atomically uniform distribution of the transition metals. The catalyst particle size is 200-300 nm. Hydrogen peroxide is produced by electrochemical water oxidation.
It achieves high selectivity (up to 70%) and high yield (the highest hydrogen peroxide yield per square centimeter electrode reaches 39.64 micromoles per minute) in hydrogen peroxide production, and achieves in-situ production without the need for hydrogen consumption.
Smart Images
Figure CN115261925B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrochemical technology, and specifically relates to a transition metal-doped titanium dioxide catalyst, its preparation method and uses, and an apparatus for producing hydrogen peroxide by electrochemical water oxidation. Background Technology
[0002] Water resources are vital to human life. Although the Earth has abundant water resources, less than 1% are available for human use. Furthermore, usable water resources are frequently polluted by urban, industrial, and agricultural activities. These pollutants require an effective and safe oxidant for complete removal through oxidation. Peroxides, represented by hydrogen peroxide, are mild and green oxidants capable of removing harmful bacteria, organic molecules, odors, and gases without leaving any residue.
[0003] Hydrogen peroxide is one of the most important basic chemicals in modern chemical industry and energy and environmental applications, with a global annual demand of approximately 4 million tons. Currently, hydrogen peroxide is mainly produced industrially via the anthraquinone process, but this method consumes large amounts of hydrogen and energy during production and poses risks during transportation. Electrochemical water oxidation selectively oxidizes water molecules to produce hydrogen peroxide, enabling on-site production, eliminating transportation hassles, and avoiding the consumption of hydrogen energy, thus achieving green synthesis.
[0004] The electrochemical oxidation of water to synthesize hydrogen peroxide requires a highly selective and active catalyst that can oxidize water by two electrons to produce hydrogen peroxide.
[0005] To address the above problems, this invention is proposed. Summary of the Invention
[0006] The first aspect of the present invention provides a transition metal-doped titanium dioxide catalyst, wherein the catalyst is a transition metal-doped titanium dioxide catalyst, and the transition metal is one of ruthenium, nickel, iron, cobalt, iron, manganese, rhodium, and palladium. The elements in the catalyst are uniformly distributed at the atomic level and exist in the form of MO-Ti coordination.
[0007] M is a transition metal atom.
[0008] Preferably, the transition metal is in a single-atom dispersed state. The catalyst particle size is 200-300 nm.
[0009] A second aspect of the present invention provides a method for preparing the transition metal-doped titanium dioxide catalyst described in the first aspect, comprising the following steps:
[0010] Step 1: Add the titanium source dropwise to the alcohol, and denote this as solution A;
[0011] Step 2: Dissolve the transition metal salt in alcohol, add water and acid, and label this solution as solution B;
[0012] Step 3: Mix solution A with solution B;
[0013] Step 4: Transfer the mixed solution from Step 3 and react it at 60℃-200℃ for 6 to 24 hours.
[0014] Step 5: Take out the product from Step 4, separate the solid and liquid, wash and dry the solid, and calcine it to obtain the transition metal-doped titanium dioxide catalyst.
[0015] Preferably, the titanium source is one of tetrabutyl titanate, isopropyl titanate, titanium sulfate, titanium oxysulfate, titanium trichloride, titanium tetrabromide, or titanium tetrachloride.
[0016] Preferably, the molar ratio of the transition metal salt to the titanium source is 1:100 to 1:5.
[0017] Preferably, the transition metal salt is any one of ruthenium chloride, ruthenium nitrite nitrate, nickel chloride, nickel nitrate, nickel sulfate, nickel acetylacetonate, ferric chloride, ferric nitrate, ferric sulfate, ferric acetylacetonate, cobalt chloride, cobalt sulfate, cobalt acetylacetonate, and cobalt nitrate.
[0018] Preferably, the acid is any one of hydrochloric acid, nitric acid, acetic acid, sulfuric acid, and oxalic acid.
[0019] Preferably, the calcination temperature is 400℃-1000℃ and the time is 1-12h.
[0020] The third aspect of this invention provides the use of the transition metal-doped titanium dioxide catalyst described in the first aspect for the electrocatalytic oxidation of water to produce hydrogen peroxide.
[0021] A fourth aspect of the present invention provides an apparatus for producing hydrogen peroxide by electrochemical water oxidation, comprising:
[0022] Anode, cathode, diaphragm, and voltage supply device;
[0023] The anode uses the catalyst described in the first aspect as the anode catalyst.
[0024] The voltage providing device is electrically connected to both the anode and the cathode.
[0025] The diaphragm is placed between the anode and the cathode;
[0026] The diaphragm is an ion exchange membrane;
[0027] The electrolyte is one of the following: sodium bicarbonate aqueous solution, potassium bicarbonate aqueous solution, sodium carbonate aqueous solution, and potassium carbonate aqueous solution.
[0028] Preferably, the conductive substrate of the anode is any one of carbon fiber paper, titanium sheet, titanium felt, and FTO.
[0029] Preferably, the cathode is one of the following: carbon rod, carbon fiber paper, platinum sheet, platinum mesh, RuS-GO, carbon black oxide, PtHg4, CoN4-C, PdCO, CoS2, or N,O-CNTs.
[0030] Preferably, the electrolyte concentration is 0.1-5 mol / L.
[0031] The fifth aspect of this invention provides a method for simultaneous production of hydrogen peroxide at both the anode and cathode, using the apparatus described in the fourth aspect;
[0032] The cathode is one of carbon black oxide, PtHg4, CoN4-C, PdCO, CoS2 or N,O-CNTs, which can achieve the effect of simultaneous production of hydrogen peroxide by coupling anodic water oxidation with cathode oxygen reduction.
[0033] The preparation methods of carbon black oxide, PtHg4, CoN4-C, PdCO, CoS2 or N,O-CNTs are well known to those skilled in the art.
[0034] The above technical solutions can be freely combined, provided they do not contradict each other.
[0035] Compared with the prior art, the beneficial effects of the present invention are:
[0036] 1. In existing technologies, compounds of transition metals such as ruthenium, nickel, cobalt, iron, manganese, and palladium are generally used for electrocatalytic oxygen production from water. However, oxygen production and hydrogen peroxide production from water are competing reactions. Technicians generally cannot use compounds of ruthenium, nickel, cobalt, iron, manganese, and palladium to catalyze hydrogen peroxide production from water.
[0037] Titanium dioxide is generally considered a photocatalyst, but its performance in producing hydrogen peroxide through electrochemical water oxidation is not good.
[0038] This invention is the first to dope transition metals ruthenium and nickel into titanium dioxide, and unexpectedly discovered that its catalytic water oxidation to hydrogen peroxide production has high selectivity (up to 70%) and high yield (the highest hydrogen peroxide yield per square centimeter electrode reaches 39.64 micromoles per minute).
[0039] 2. The transition metal-doped titanium dioxide catalyst proposed in this invention is wherein the transition metal is atomically uniformly dispersed and exists in a MO-Ti coordination form.
[0040] 3. The method of the present invention for producing hydrogen peroxide by electrochemical water oxidation only requires the electrolyte to provide the reactants and does not require gasification, thus realizing the in-situ production of hydrogen peroxide.
[0041] 4. The electrode for producing hydrogen peroxide by electrochemical water oxidation proposed in this invention is coupled with the corresponding catalytic electrode for the cathode oxygen reduction reaction, which can realize the simultaneous in-situ production of hydrogen peroxide at both the cathode and anode. Attached Figure Description
[0042] Figure 1 This is a schematic diagram of the H-type electrolytic cell used for electrochemical testing in this invention.
[0043] Figure 2 The image shows the X-ray diffraction (XRD) pattern of the ruthenium-doped titanium dioxide catalyst in Example 1.
[0044] Figure 3 This is a transmission electron microscope image of the ruthenium-doped titanium dioxide catalyst in Example 1.
[0045] Figure 4 This is an elemental distribution diagram of the ruthenium-doped titanium dioxide catalyst in Example 1.
[0046] Figure 5 The image shows the X-ray diffraction (XRD) pattern of the nickel-doped titanium dioxide catalyst in Example 2.
[0047] Figure 6 This is a transmission electron microscope image of the transition metal nickel-doped titanium dioxide catalyst in Example 2.
[0048] Figure 7 This is an elemental distribution diagram of the nickel-doped titanium dioxide catalyst in Example 2.
[0049] Figure 8 Linear sweep voltammetry (LSV) plot of the ruthenium-doped titanium dioxide electrode in Application Example 1.
[0050] Figure 9 The graph shows the selectivity curves of the ruthenium-doped titanium dioxide electrode in Application Example 1 at different voltages.
[0051] Figure 10 The graph shows the hydrogen peroxide production rate at different voltages for the transition metal ruthenium-doped titanium dioxide electrode used in Example 1.
[0052] Figure 11 The linear sweep voltammetry (LSV) plot is shown for the transition metal nickel-doped titanium dioxide electrode in Application Example 2.
[0053] Figure 12 The graph shows the selectivity curves of the nickel-doped titanium dioxide electrode in Application Example 2 at different voltages.
[0054] Figure 13 The graph shows the hydrogen peroxide production rate at different voltages using the nickel-doped titanium dioxide electrode in Application Example 2.
[0055] Figure 14 The image shows the X-ray diffraction (XRD) pattern of the titanium dioxide catalyst in Comparative Example 1.
[0056] Figure 15 The graph shows the selectivity curves of the titanium dioxide electrode in Comparative Example 1 at different voltages.
[0057] Figure 16 The graph shows the hydrogen peroxide production rate of the titanium dioxide electrode in Comparative Example 1 under different voltages.
[0058] Figure 17 The graph shows the selectivity curves of the carbon fiber paper electrode under different voltages in Comparative Example 2.
[0059] Figure 18 The graph shows the hydrogen peroxide production rate of the carbon fiber paper electrode in Comparative Example 2 under different voltages.
[0060] Figure 19 This is a transmission electron microscope image with spherical aberration correction of the transition metal ruthenium-doped titanium dioxide catalyst in Example 1.
[0061] Figure 20 The image shows the near-edge X-ray absorption structure of Ru k-side in the transition metal ruthenium-doped titanium dioxide catalyst in Example 1.
[0062] Figure 21 The image shows the Fourier transform spectrum of the fine structure of Ru k-edge X-ray absorption in the transition metal ruthenium-doped titanium dioxide catalyst in Example 1.
[0063] Figure 22 The image shows the near-edge structure of Ni k-edge X-ray absorption in the transition metal nickel-doped titanium dioxide catalyst in Example 2.
[0064] Figure 23 The image shows the Fourier transform spectrum of the fine structure of Ni k-edge X-ray absorption in the transition metal nickel-doped titanium dioxide catalyst in Example 2.
[0065] Figure 24 The bar chart shows the overall Faraday efficiency of the anode and cathode under different voltages in Application Example 3. Detailed Implementation
[0066] The present invention will be further described below through embodiments, but is not limited to these embodiments. Experimental methods not specifically described in the embodiments generally use conventional conditions and conditions described in the manual, or conditions recommended by the manufacturer. The general equipment, materials, reagents, etc., used are all commercially available unless otherwise specified. The raw materials used in the following embodiments and comparative examples are all commercially available.
[0067] Example 1
[0068] This embodiment relates to an electrode for preparing highly selective and highly active electrochemical water oxidation to produce hydrogen peroxide, using carbon fiber paper as a conductive substrate, tetrabutyl titanate as a titanium source for synthesis precursor, ruthenium trichloride as a doped transition metal salt, and anhydrous ethanol as a hydrothermal reaction solvent.
[0069] Step 1: Measure 1 ml of titanium tetrachloride and add it dropwise to 10 ml of anhydrous ethanol, and record this as solution A;
[0070] Step 2: Weigh 0.1510g of ruthenium trichloride and dissolve it in 20ml of anhydrous ethanol. Add 2ml of deionized water and 2ml of glacial acetic acid. This solution is labeled as solution B.
[0071] Step 3: Mix solution A with solution B;
[0072] Step 4: Transfer the mixed solution from Step 3 to a 50ml reaction vessel liner and react in an oven at 110℃ for 11 hours.
[0073] Step 5: Take out the product from Step 4 and place it in a 50ml centrifuge tube. Centrifuge to obtain powder material. Wash it 2-3 times with 0.1mol / L ammonia solution and deionized water respectively, and dry it overnight in an oven at 80℃.
[0074] Step 6: Spread the powder material dried overnight in Step 5 evenly on the bottom of the ceramic boat, place the ceramic boat in a tube furnace, and calcine at 800°C for 2 hours in an air atmosphere to obtain a transition metal ruthenium-doped titanium dioxide catalyst.
[0075] Figure 1 This is a schematic diagram of the H-type electrolytic cell used for electrochemical testing in this invention. Figure 2 This is the X-ray diffraction (XRD) pattern of the transition metal ruthenium-doped titanium dioxide catalyst in Example 1 of the present invention. Figure 3 This is a transmission electron microscope image of the ruthenium-doped titanium dioxide catalyst in Example 1 of the present invention. Figure 4 This is an elemental distribution diagram of the ruthenium-doped titanium dioxide catalyst in Example 1 of the present invention.
[0076] like Figure 2 The synthesized ruthenium-doped titanium dioxide catalyst shown is a pure rutile phase with no other diffraction peaks. Figure 3 As shown, the synthesized ruthenium-doped titanium dioxide catalyst has a particle size of approximately 200-300 nm. Figure 4 As shown, the material is composed of ruthenium, titanium, and oxygen; and the various elements are evenly distributed throughout the material. Figures 19-21 As shown, Ru in this catalyst is distributed in the form of single atoms. The k-edge X-ray absorption fine structure Fourier transform spectrum of Ru shows that Ru exists in the synthesized catalyst in the form of Ru-O-Ti coordination.
[0077] Step 7: Grind the catalyst obtained in Step 6 in a mortar; weigh 5 mg of the ground catalyst into 1 ml of isopropanol, and disperse it by ultrasonication to obtain catalyst ink.
[0078] Step 8: Cut 1cm*2cm carbon fiber paper, sonicate the carbon fiber paper in anhydrous ethanol to remove surface stains; drop the catalyst ink obtained in step 7 onto a 1cm*1cm area of the carbon fiber paper; obtain an electrode for electrochemical water oxidation to produce hydrogen peroxide.
[0079] Example 2
[0080] This embodiment relates to an electrode for preparing highly selective and highly active electrochemical water oxidation to produce hydrogen peroxide, using carbon fiber paper as a conductive substrate, titanium tetrachloride as a titanium source for synthesis precursor, nickel nitrate as a doped transition metal salt, and anhydrous ethanol as a hydrothermal reaction solvent.
[0081] Step 1: Measure 1 ml of tetrabutyl titanate and add it dropwise to 10 ml of anhydrous ethanol, and record this as solution C;
[0082] Step 2: Weigh 0.1106g of nickel nitrate and dissolve it in 20ml of anhydrous ethanol. Add 2ml of deionized water and 2ml of glacial acetic acid. This solution is labeled as solution D.
[0083] Step 3: Add solution C dropwise to solution D;
[0084] Step 4: Transfer the mixed solution from Step 3 to a 50ml reaction vessel liner and react in an oven at 150℃ for 8 hours.
[0085] Step 5: Take out the product from Step 4 after the reaction is complete, place it in a 50ml centrifuge tube, centrifuge to obtain powder material, wash it 2-3 times with deionized water, and dry it overnight in an 80℃ oven.
[0086] Step 6: Spread the powder material dried overnight in Step 5 evenly on the bottom of the ceramic boat, place the ceramic boat in a tube furnace, and calcine at 700°C for 2 hours in an air atmosphere to obtain a transition metal nickel-doped titanium dioxide catalyst.
[0087] Figure 5 This is the X-ray diffraction (XRD) pattern of the transition metal nickel-doped titanium dioxide catalyst in Example 2 of the present invention. Figure 6 This is a transmission electron microscope image of the transition metal nickel-doped titanium dioxide catalyst in Example 2 of the present invention. Figure 7 This is an elemental distribution diagram of the nickel-doped titanium dioxide catalyst in Example 2 of the present invention.
[0088] like Figure 5The synthesized nickel-doped transition metal titanium dioxide catalyst shown is a pure rutile phase with no other diffraction peaks. For example... Figure 6 As shown, the synthesized transition metal nickel-doped titanium dioxide catalyst has a particle size of approximately 200-300 nm. Figure 7 The material is composed of nickel, titanium, and oxygen; and these elements are evenly distributed throughout the material. Figures 22-23 As shown, Ni exists in the catalyst in the form of single atoms, and Ni exists in the coordination form of Ni-O-Ti.
[0089] Step 7: Grind the catalyst obtained in Step 6 in a mortar; weigh 5 mg of the ground catalyst into 1 ml of isopropanol, and disperse it by ultrasonication to obtain catalyst ink.
[0090] Step 8: Cut 1cm*2cm carbon fiber paper, sonicate the carbon fiber paper in anhydrous ethanol to remove surface stains; drop the catalyst ink obtained in step 7 onto a 1cm*1cm area of the carbon fiber paper; obtain an electrode for electrochemical water oxidation to produce hydrogen peroxide.
[0091] Application Example 1
[0092] The electrode prepared in Example 1 was subjected to... Figure 1 Electrochemical tests were performed using an H-type testing system. The specific structure of the H-type testing system includes an electrochemical workstation 1, an H-type electrolytic cell 2, and an ion-exchange membrane 3. The electrochemical workstation 1 includes a reference electrode clamp 4, a working electrode clamp 5, and a counter electrode clamp 6. The reference electrode 21 of the H-type electrolytic cell 2 is connected to the reference electrode clamp 4 of the electrochemical workstation 1, the working electrode 22 of the H-type electrolytic cell 2 is connected to the working electrode clamp 5 of the electrochemical workstation 1, and the counter electrode 23 of the H-type electrolytic cell 2 is connected to the counter electrode clamp 6 of the electrochemical workstation 1. A proton exchange membrane is placed between the anode chamber 7 and the cathode chamber 8 to separate the anode and cathode chambers.
[0093] The ion-exchange membrane is a Nafion membrane. The counter electrode is a carbon rod electrode. The reference electrode is a silver / silver chloride electrode.
[0094] Using the electrode prepared in Example 1 as the working electrode, through... Figure 1 Electrochemical tests were performed using the H-type test system. The electrolyte was a 2 mol / L potassium bicarbonate solution.
[0095] The results are as follows Figure 8 As shown, the current density reaches 10 mA cm⁻¹ -2 At this point, the peak potential is approximately 1.95V, indicating that this electrode possesses oxygen evolution reaction inertness, thus exhibiting good selectivity for two-electron water oxidation, and the current density can reach up to 120mA cm⁻¹. -2 .
[0096] The electrode prepared in Example 1 was subjected to... Figure 1 The H-type test system was used to test hydrogen peroxide production, and the selectivity and yield of hydrogen peroxide production by electrochemical water oxidation with a ruthenium-doped titanium dioxide electrode were calculated. Figure 9 As shown, the selectivity of the electrode for the oxidation of water to hydrogen peroxide with two electrons varies with the applied potential; by applying different potentials of 2.7-3.2V on an electrochemical workstation, the changes in the electrode selectivity and yield at different voltages were tested; the results are as follows. Figure 9 and Figure 10 As shown, when the applied potential is 3.1V, the selectivity for the oxidation of water to hydrogen peroxide by the ruthenium-doped titanium dioxide electrode reaches the highest level of 62.8%; the hydrogen peroxide yield per square centimeter of electrode reaches a maximum of 22.4 micromoles per minute.
[0097] Application Example 2
[0098] The electrode prepared in Example 2 was subjected to... Figure 1 Electrochemical tests were performed using an H-type testing system. The specific structure of the H-type testing system includes an electrochemical workstation 1, an H-type electrolytic cell 2, and an ion-exchange membrane 3. The electrochemical workstation 1 includes a reference electrode clamp 4, a working electrode clamp 5, and a counter electrode clamp 6. The reference electrode 21 of the H-type electrolytic cell 2 is connected to the reference electrode clamp 4 of the electrochemical workstation 1, the working electrode 22 of the H-type electrolytic cell 2 is connected to the working electrode clamp 5 of the electrochemical workstation 1, and the counter electrode 23 of the H-type electrolytic cell 2 is connected to the counter electrode clamp 6 of the electrochemical workstation 1. A proton exchange membrane is placed between the anode chamber 7 and the cathode chamber 8 to separate the anode and cathode chambers.
[0099] The ion-exchange membrane is a Nafion membrane. The counter electrode is a carbon rod electrode. The reference electrode is a silver / silver chloride electrode.
[0100] The electrode prepared in Example 2 was subjected to... Figure 1 Electrochemical tests were performed on the H-type test system. The electrolyte was a 2 mol / L potassium bicarbonate solution. The results are as follows: Figure 11 As shown, the current density reaches 10 mA cm⁻¹ -2 At this point, the peak potential is approximately 1.975V, indicating that this electrode possesses oxygen evolution reaction inertness, thus exhibiting good selectivity for two-electron water oxidation, and the current density can reach up to 120mA cm⁻¹. -2 .
[0101] The electrode prepared in Example 2 was subjected to... Figure 1 The H-type test system was used to test hydrogen peroxide production, and the selectivity and yield of hydrogen peroxide production by electrochemical water oxidation using a nickel-doped titanium dioxide electrode were calculated. Figure 12 As shown, the selectivity of the electrode for the oxidation of water to hydrogen peroxide with two electrons varies with the applied potential; by applying different potentials of 2.8-3.3V on an electrochemical workstation, the changes in the selectivity and yield of the electrode under different voltages were tested; the results are as follows. Figure 12 and Figure 13 As shown, when the applied potential is 3.2V, the selectivity for the oxidation of water to hydrogen peroxide by the ruthenium-doped titanium dioxide electrode reaches the highest level of 70.05%; the hydrogen peroxide yield per square centimeter of electrode reaches a maximum of 39.64 micromoles per minute.
[0102] Comparative Example 1
[0103] This embodiment relates to an electrode for preparing an electrochemical water oxidation to produce hydrogen peroxide without transition metal doping, using carbon fiber paper as a conductive substrate, titanium tetrachloride as a titanium source for synthesis precursor, and anhydrous ethanol as a hydrothermal reaction solvent.
[0104] Step 1: Measure 1 ml of titanium tetrachloride and add it dropwise to 10 ml of anhydrous ethanol, and record it as solution E;
[0105] Step 2: Add 2 ml of deionized water and 2 ml of glacial acetic acid to 20 ml of anhydrous ethanol, and denote this as solution F;
[0106] Step 3: Add solution E dropwise to solution F;
[0107] Step 4: Transfer the mixed solution from Step 3 to a 50ml reaction vessel liner and react in an oven at 110℃ for 11 hours.
[0108] Step 5: Take out the product from Step 4 and place it in a 50ml centrifuge tube. Centrifuge to obtain powder material. Wash it 2-3 times with 0.1mol / L ammonia solution and deionized water respectively, and dry it overnight in an oven at 80℃.
[0109] Step 6: Spread the powder material dried overnight in Step 5 evenly on the bottom of the ceramic boat, place the ceramic boat in a tube furnace, and calcine at 900°C for 2 hours in an air atmosphere to obtain the titanium dioxide catalyst.
[0110] Characterizing materials: such as Figure 14 The synthesized titanium dioxide catalyst shown is pure rutile phase and has no other diffraction peaks.
[0111] Step 7: Grind the catalyst obtained in Step 6 in a mortar; weigh 5 mg of the ground catalyst into 1 ml of isopropanol, and disperse it by ultrasonication to obtain catalyst ink.
[0112] Step 8: Cut 1cm*2cm carbon fiber paper, sonicate the carbon fiber paper in anhydrous ethanol to remove surface stains; drop the catalyst ink obtained in step 7 onto a 1cm*1cm area of the carbon fiber paper; obtain an electrode for electrochemical water oxidation to produce hydrogen peroxide.
[0113] Using the electrode prepared in this embodiment as the working electrode, and referring to Application Example 1, by... Figure 1The H-type test system was used to test hydrogen peroxide production, and the selectivity and yield of hydrogen peroxide production by electrochemical water oxidation using a titanium dioxide electrode were calculated. The results are as follows: Figure 15 and Figure 16 As shown, the selectivity for hydrogen peroxide production via the two-electron oxidation of water using the titanium dioxide electrode is up to 11.75%, and the highest yield per square centimeter of electrode is 4.79 micromoles per minute. Therefore, the selectivity and yield of hydrogen peroxide production using the titanium dioxide electrode are far lower than those of the catalyst of this invention.
[0114] Comparative Example 2
[0115] Using a carbon fiber paper conductive substrate without a drop-coated catalyst as the working electrode, and referring to Application Example 1, through... Figure 1 The H-type test system was used to test hydrogen peroxide production, and the selectivity and yield of hydrogen peroxide production by electrochemical water oxidation using carbon fiber paper electrodes were calculated. The results are as follows: Figure 17 and Figure 18 As shown, the carbon fiber paper electrode exhibits the highest selectivity of 3.98% for the oxidation of water to hydrogen peroxide using two electrons; the highest yield per square centimeter of electrode is 1.83 micromoles per minute.
[0116] Therefore, in Comparative Example 2, the selectivity and yield of water oxidation to hydrogen peroxide on the carbon fiber paper conductive substrate without the drop-coated catalyst are far lower than those on the carbon fiber paper conductive substrate with the drop-coated catalyst of the present invention.
[0117] Application Example 3
[0118] This example relates to a method for simultaneously producing hydrogen peroxide at both the anode and cathode using a ruthenium-doped titanium dioxide electrode as the anode and an N,O-CNTs electrode (electrode preparation method can be found in doi.org / 10.1002 / advs.202201421) as the cathode.
[0119] The anode and cathode prepared in this embodiment are passed through... Figure 1 Electrochemical tests were performed using an H-type testing system. The specific structure of the H-type testing system includes an electrochemical workstation 1, an H-type electrolytic cell 2, and an ion-exchange membrane 3. The electrochemical workstation 1 includes a reference electrode clamp 4, a working electrode clamp 5, and a counter electrode clamp 6. The reference electrode 21 of the H-type electrolytic cell 2 is connected to the reference electrode clamp 4 of the electrochemical workstation 1, the working electrode 22 of the H-type electrolytic cell 2 is connected to the working electrode clamp 5 of the electrochemical workstation 1, and the counter electrode 23 of the H-type electrolytic cell 2 is connected to the counter electrode clamp 6 of the electrochemical workstation 1. A proton exchange membrane is placed between the anode chamber 7 and the cathode chamber 8 to separate the anode and cathode chambers.
[0120] The ion exchange membrane is a Nafion membrane. The working electrode is a ruthenium-doped titanium dioxide electrode, the counter electrode is an N,O-CNTs electrode, and the reference electrode is a silver / silver chloride electrode.
[0121] The anode and cathode prepared in this embodiment are passed through... Figure 1 Electrochemical tests were performed on the H-type test system. The anolyte was a 2 mol / L potassium bicarbonate solution, and the cathode electrolyte was a 1 mol / L potassium hydroxide solution. The results are as follows: Figure 24 As shown, with a total voltage in the range of 2.1-2.7V, the overall Faraday efficiency of the anode and cathode exceeds 100%, enabling the simultaneous production of hydrogen peroxide at both the anode and cathode.
Claims
1. The use of a transition metal-doped titanium dioxide catalyst for the electrocatalytic oxidation of water to produce hydrogen peroxide, characterized in that, The catalyst is a transition metal-doped titanium dioxide catalyst, wherein the transition metal is one of ruthenium and nickel, and the elements in the catalyst are uniformly distributed at the atomic level and exist in the form of MO-Ti coordination. M is a transition metal atom; The transition metal ruthenium-doped titanium dioxide catalyst is a pure rutile phase with a particle size of 200-300 nm. The transition metal nickel-doped titanium dioxide catalyst is a pure rutile phase with a particle size of 200-300 nm. The preparation method of the transition metal-doped titanium dioxide catalyst includes the following steps: Step 1: Add the titanium source dropwise to the alcohol, and denote this as solution A; Step 2: Dissolve the transition metal salt in alcohol, add water and acid, and label this solution as solution B; Step 3: Mix solution A with solution B; Step 4: React the mixed solution from Step 3 at 60℃-200℃ for 6~24 hours; Step 5: Take out the product from Step 4, separate the solid and liquid, wash and dry the solid, and calcine it to obtain the transition metal-doped titanium dioxide catalyst. The molar ratio of the transition metal salt to the titanium source is 1:100-1:5; The calcination temperature is 400℃-1000℃, and the time is 1-12h.
2. The use according to claim 1, characterized in that, The titanium source is one of tetrabutyl titanate, isopropyl titanate, titanium sulfate, titanium oxysulfate, titanium trichloride, titanium tetrabromide, or titanium tetrachloride.
3. The use according to claim 1, characterized in that, The transition metal salt is any one of ruthenium chloride, ruthenium nitrite nitrate, nickel chloride, nickel nitrate, nickel sulfate, and nickel acetylacetonate; The acid is any one of hydrochloric acid, nitric acid, acetic acid, sulfuric acid, and oxalic acid.