High-activity oer electrocatalyst, and preparation method and application thereof
Patent Information
- Application Number
- CN202311280155.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-28
- Publication Date
- 2026-10-30
- Estimated Expiration
- 2043-09-28
AI Technical Summary
电化学氧化法依赖于电化学工作站，而且金属态Ir需要事先涂在工作电极表面、在一定电位范围内通过动电位扫描后逐渐转变为IrOx(OH)y，此法生产效率极低，不利于析氧活性物的大规模生产
[0025](1)本发明采用一种简单易行的诱导水解方法，不使用任何有机试剂，借助高比表面积的过渡金属的氧化物和/或氮化物与水溶性铱盐之间的相互作用，在特定温度下使得Ir离子一步转化成羟基氧化铱。该方法简单有效，绿色环保，得到的羟基氧化铱不需要经过额外的氧化步骤就具有高的OER活性；此外，其在诱导物表面沉积有助于提高贵金属Ir的原子利用率，可作为高活性析氧催化剂用于水电解池的阳极。
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of water electrolysis for hydrogen production technology, specifically relating to a highly active OER electrocatalyst for water electrolysis for hydrogen production, its preparation method, and its application. Background Technology
[0002] Hydrogen energy is considered the most promising energy carrier to replace traditional fossil fuels. Compared with other energy sources, hydrogen has a high calorific value (140 MJ / kg), which is 3.26 times that of crude oil, 3.87 times that of natural gas, and 5.19 times that of coke. Furthermore, its combustion product is water, making it widely recognized as a clean energy source. Given the current severe "three abandonments" (abandoned water, wind, and solar power) problem in my country, utilizing renewable energy for water electrolysis to produce hydrogen has significant economic value. In recent years, proton exchange membrane (PEM) water electrolysis technology has become a research hotspot in the field of water electrolysis for hydrogen production due to its advantages such as high efficiency, zero emissions, compact structure, environmental friendliness, and high product purity. In the PEM water electrolysis process, the oxygen evolution reaction (OER) at the anode is a four-electron-proton coupled reaction. Oxidation evolution potential (OER) is extremely slow kinetically and is considered the main source of overpotential in electrolyzers. High overpotential means high energy consumption and low energy utilization. Furthermore, high overpotential exacerbates the electro-oxidative corrosion of materials (such as catalysts, diffusion layers, and bipolar plates). Therefore, much research has focused on designing highly efficient OER electrocatalysts to reduce OER overpotential. Currently, considering both oxygen evolution activity and corrosion resistance, the main material suitable for PEM (polyhydric oxygen evolution membrane) anode catalysts for water electrolysis to produce hydrogen is the noble metal iridium (Ir). It is worth noting that metallic Ir exhibits very poor OER activity; it only acquires considerable OER activity after oxidation. Generally, Ir oxides can be prepared by thermal oxidation or electrochemical oxidation. However, the OER activity of thermally oxidized iridium oxide is lower than that of electrochemically oxidized iridium hydroxyoxide (IrO). x (OH) y Electrochemical oxidation relies on an electrochemical workstation, and metallic Ir needs to be pre-coated onto the surface of the working electrode and gradually transformed into IrO through potentiodynamic scanning within a certain potential range. x (OH) y This method has extremely low production efficiency and is not conducive to the large-scale production of oxygen evolution reactive substances. Summary of the Invention
[0003] Therefore, the purpose of this invention is to provide a highly active OER electrocatalyst for hydrogen production by water electrolysis, its preparation method and application. This invention uses oxides and / or nitrides of transition metals with high specific surface area as supports and inducers, and converts water-soluble Ir salts into iridium hydroxyoxides through a one-step hydrothermal method. The oxides do not require additional oxidation steps and have good OER activity.
[0004] To achieve the above objectives, the present invention provides the following technical solution:
[0005] This invention provides a method for preparing a highly active OER electrocatalyst, using oxides and / or nitrides of transition metals as inducing supports. The induced hydrolysis of the inducing supports promotes the transformation of iridium salts into highly active oxygen evolution iridium hydroxyoxides, which are then deposited on the surface of the inducing supports to obtain a highly active OER electrocatalyst.
[0006] Based on the above technical solution, the preparation method further includes the following steps:
[0007] 1) Add the inducing carrier to water and disperse it evenly to obtain the first dispersion;
[0008] 2) Preheat the first dispersion at 100-300℃ to obtain the second dispersion;
[0009] 3) Add the Ir precursor solution to the second dispersion and react at 100-300℃ for at least 1 hour to obtain the third dispersion;
[0010] 4) Separate the solids in the third dispersion to obtain the highly active OER electrocatalyst.
[0011] Based on the above technical solution, further, the dispersion mentioned in step 1) includes ultrasonic dispersion and stirring dispersion.
[0012] Based on the above technical solution, further, the concentration of the first dispersion in step 1) is 0.1-10 mg / mL.
[0013] Based on the above technical solution, further, in step 1), the transition metal oxide is at least one of TiO2, Ti4O7, Nb2O5, and Ta2O5, and the transition metal nitride is at least one of TiN, NbN, and TaN.
[0014] Based on the above technical solution, further, in step 2), the preheating temperature is 100-200℃; the preheating time is more than 10 minutes.
[0015] Based on the above technical solution, further, in step 3), the Ir precursor solution is an aqueous solution of a soluble salt or soluble acid of Ir, preferably an aqueous solution of at least one of IrCl3, IrCl4, H2IrCl6, K2IrCl6, and (NH4)2IrCl6.
[0016] Based on the above technical solution, further, in step 3), the mass ratio of Ir in the Ir precursor solution to the inducing carrier in the second dispersion is 1:9-9:1.
[0017] Based on the above technical solution, further, in step 3), the reaction temperature is 100-200℃, and the reaction time is at least 6 hours, preferably at least 12 hours.
[0018] Based on the above technical solution, further, in step 4), the separation method includes filtration and centrifugation, and the separated solids are washed with water and dried to obtain a highly active OER electrocatalyst.
[0019] In another aspect, the present invention provides a highly active OER electrocatalyst prepared by the above-described preparation method.
[0020] Based on the above technical solution, the highly active OER electrocatalyst further uses iridium hydroxyoxide as the active component.
[0021] Based on the above technical solution, the iridium hydroxyoxide is in the form of nanoparticles (≤5 nanometers), which are dispersed and deposited on the surface of the induction carrier in the form of single particles, or in the form of multiple nanoparticles agglomerated together to form aggregates covering the surface of the induction carrier.
[0022] This invention also provides the application of the above-mentioned highly active OER electrocatalyst in water electrolysis for hydrogen production.
[0023] Based on the above technical solution, the highly active OER electrocatalyst is further used as an anode oxygen evolution catalyst.
[0024] Compared with the prior art, the present invention has the following beneficial effects:
[0025] (1) This invention employs a simple and easy-to-implement induced hydrolysis method that does not use any organic reagents. It utilizes the interaction between the high specific surface area of transition metal oxides and / or nitrides and water-soluble iridium salts to convert Ir ions into iridium hydroxyoxide in a single step at a specific temperature. This method is simple, effective, and environmentally friendly. The resulting iridium hydroxyoxide exhibits high OER activity without requiring additional oxidation steps. Furthermore, its deposition on the inducer surface helps improve the atomic utilization of the noble metal Ir, making it suitable as a highly active oxygen evolution catalyst for use as the anode in water electrolysis cells.
[0026] (2) The preparation method of the present invention is simpler than the traditional electrochemical oxidation method. It does not rely on an electrochemical workstation and a slow potentiodynamic scanning process. It is a simple, efficient and green synthesis method that is suitable for large-scale production.
[0027] (3) The oxygen evolution catalyst prepared by the present invention has a high OER active component - iridium hydroxyl oxide. When used as an oxygen evolution catalyst, it does not need to undergo thermal oxidation or electrochemical oxidation process and has high oxygen evolution activity. Its OER activity is much higher than that of commercial iridium oxide catalysts. Attached Figure Description
[0028] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof.
[0029] Figure 1 This is a transmission electron microscope (TEM) image of the OER electrocatalyst prepared in Example 1.
[0030] Figure 2 This is a comparison of the OER polarization curves of the OER electrocatalyst prepared in Example 1 and the commercial iridium oxide catalyst in an O2-saturated 0.1M HClO4 solution.
[0031] Figure 3 This is a transmission electron microscope (TEM) image of the OER electrocatalyst prepared in Example 6.
[0032] Figure 4 This is a comparison of the OER polarization curves of the comparative catalyst prepared in Comparative Example 2 before and after electrochemical oxidation in an O2-saturated 0.1M HClO4 solution. Detailed Implementation
[0033] The present invention will be described in detail below with reference to the embodiments. However, the implementation of the present invention is not limited thereto. Obviously, the embodiments described below are only some embodiments of the present invention. For those skilled in the art, other similar embodiments can be obtained without creative effort and all fall within the protection scope of the present invention.
[0034] Example 1:
[0035] This embodiment provides a method for preparing a highly active OER electrocatalyst for hydrogen production by water electrolysis, comprising the following steps:
[0036] 1. Accurately weigh 10 mg of commercially available nano TiO2 powder and add it to 5 mL of deionized water, then ultrasonically disperse for 15 min;
[0037] 2. After preheating the above dispersion at 100℃ for 15 min, add the pre-prepared H2IrCl6 aqueous solution so that the mass ratio of Ir to TiO2 is 1:9, and then react at 100℃ for 24 h.
[0038] 3. After the reaction is complete, the mixture is allowed to cool naturally to room temperature, then centrifuged and washed four times with deionized water to obtain a highly active OER electrocatalyst.
[0039] Figure 1 This is a transmission electron microscope (TEM) image of the OER electrocatalyst prepared in Example 1. As can be seen from the image, iridium hydroxyoxide nanoparticles (≤5 nm) are uniformly dispersed on the surface of the TiO2 support.
[0040] Figure 2 This is a comparison of the OER polarization curves of the OER electrocatalyst prepared in Example 1 and the commercial iridium oxide catalyst (Johnson Matthey) in an O2-saturated 0.1M HClO4 solution. The OER polarization curve testing conditions were: ensuring the same catalyst loading (Ir loading of 20 μg / cm³). 2 Linear scan polarization testing was performed at a linear scan rate of 5 mV / s, with a potential scan range of 800–1366 mV vs. SCE, in a forward scan. Figure 2 It is evident that the oxygen evolution activity of the catalyst prepared in this embodiment is significantly higher than that of commercial iridium oxide. The current density results of the OER electrocatalyst prepared in this embodiment and the commercial iridium oxide catalyst at 1366 mV vs. SCE potential are shown in Table 1.
[0041] Example 2:
[0042] This embodiment provides a method for preparing a highly active OER electrocatalyst for hydrogen production by water electrolysis, comprising the following steps:
[0043] 1. Accurately weigh 10 mg of commercially available nano Ti4O7 powder and add it to 10 mL of deionized water, then ultrasonically disperse for 15 min;
[0044] 2. After preheating the above dispersion at 120℃ for 15 min, add the pre-prepared H2IrCl6 aqueous solution so that the mass ratio of Ir to Ti4O7 is 1:3, and then react at 120℃ for 24 h.
[0045] 3. After the reaction is complete, the mixture is allowed to cool naturally to room temperature, then centrifuged and washed four times with deionized water to obtain a highly active OER electrocatalyst.
[0046] The current density of the OER electrocatalyst prepared in this example at a potential of 1366 mV vs. SCE is shown in Table 1.
[0047] Example 3:
[0048] This embodiment provides a method for preparing a highly active OER electrocatalyst for hydrogen production by water electrolysis, comprising the following steps:
[0049] 1. Accurately weigh 10 mg of commercially available nano Nb2O5 powder and add it to 20 mL of deionized water, then ultrasonically disperse for 15 min;
[0050] 2. After preheating the above dispersion at 120℃ for 15 min, add the pre-prepared H2IrCl6 aqueous solution so that the mass ratio of Ir to Nb2O5 is 1:2, and then react at 120℃ for 24 h.
[0051] 3. After the reaction is complete, the mixture is allowed to cool naturally to room temperature, then centrifuged and washed four times with deionized water to obtain a highly active OER electrocatalyst.
[0052] The current density of the OER electrocatalyst prepared in this example at a potential of 1366 mV vs. SCE is shown in Table 1.
[0053] Example 4:
[0054] This embodiment provides a method for preparing a highly active OER electrocatalyst for hydrogen production by water electrolysis, comprising the following steps:
[0055] 1. Accurately weigh 10 mg of commercially available nano Ta2O5 powder and add it to 5 mL of deionized water, then ultrasonically disperse for 15 min;
[0056] 2. After preheating the above dispersion at 150℃ for 30 min, add the pre-prepared H2IrCl6 aqueous solution so that the mass ratio of Ir to Ta2O5 is 1:1, and then react at 150℃ for 18 h.
[0057] 3. After the reaction is complete, the mixture is allowed to cool naturally to room temperature, then centrifuged and washed four times with deionized water to obtain a highly active OER electrocatalyst.
[0058] The current density of the OER electrocatalyst prepared in this example at a potential of 1366 mV vs. SCE is shown in Table 1.
[0059] Example 5:
[0060] This embodiment provides a method for preparing a highly active OER electrocatalyst for hydrogen production by water electrolysis, comprising the following steps:
[0061] 1. Accurately weigh 10 mg of commercially available nano TiN powder and add it to 5 mL of deionized water, then ultrasonically disperse for 15 min;
[0062] 2. After preheating the above dispersion at 180℃ for 15 min, add the pre-prepared H2IrCl6 aqueous solution so that the mass ratio of Ir to TiN is 1:1, and then react at 180℃ for 15 h.
[0063] 3. After the reaction is complete, the mixture is allowed to cool naturally to room temperature, then centrifuged and washed four times with deionized water to obtain a highly active OER electrocatalyst.
[0064] The current density of the OER electrocatalyst prepared in this example at a potential of 1366 mV vs. SCE is shown in Table 1.
[0065] Example 6:
[0066] This embodiment provides a method for preparing a highly active OER electrocatalyst for hydrogen production by water electrolysis, comprising the following steps:
[0067] 1. Accurately weigh 10 mg of commercially available nano NbN powder and add it to 5 mL of deionized water, then ultrasonically disperse for 15 min;
[0068] 2. After preheating the above dispersion at 200℃ for 15 min, add the pre-prepared H2IrCl6 aqueous solution so that the mass ratio of Ir to NbN is 1:1, and then react at 200℃ for 12 h.
[0069] 3. After the reaction is complete, the mixture is allowed to cool naturally to room temperature, then centrifuged and washed four times with deionized water to obtain a highly active OER electrocatalyst.
[0070] Figure 3 This is a transmission electron microscope (TEM) image of the OER electrocatalyst prepared in Example 6. As can be seen from the image, iridium hydroxyoxide nanoparticles are aggregated together and cover the surface of the NbN support.
[0071] The current density of the OER electrocatalyst prepared in this example at a potential of 1366 mV vs. SCE is shown in Table 1.
[0072] Example 7:
[0073] This embodiment provides a method for preparing a highly active OER electrocatalyst for hydrogen production by water electrolysis, comprising the following steps:
[0074] 1. Accurately weigh 10 mg of commercially available nano TaN powder and add it to 10 mL of deionized water, then ultrasonically disperse for 15 min;
[0075] 2. After preheating the above dispersion at 200℃ for 60 min, add the pre-prepared H2IrCl6 aqueous solution so that the mass ratio of Ir to TaN is 2:1, and then react at 200℃ for 12 h.
[0076] 3. After the reaction is complete, the mixture is allowed to cool naturally to room temperature, then centrifuged and washed four times with deionized water to obtain a highly active OER electrocatalyst.
[0077] The current density of the OER electrocatalyst prepared in this example at a potential of 1366 mV vs. SCE is shown in Table 1.
[0078] Example 8:
[0079] This embodiment provides a method for preparing a highly active OER electrocatalyst for hydrogen production by water electrolysis, comprising the following steps:
[0080] 1. Accurately weigh 10 mg of commercially available nano TiO2 powder and add it to 15 mL of deionized water, then ultrasonically disperse for 15 min;
[0081] 2. After preheating the above dispersion at 100℃ for 15 min, add the pre-prepared IrCl3 aqueous solution so that the mass ratio of Ir to TiO2 is 3:1, and then react at 100℃ for 24 h.
[0082] 3. After the reaction is complete, the mixture is allowed to cool naturally to room temperature, then centrifuged and washed four times with deionized water to obtain a highly active OER electrocatalyst.
[0083] The current density of the OER electrocatalyst prepared in this example at a potential of 1366 mV vs. SCE is shown in Table 1.
[0084] Example 9:
[0085] This embodiment provides a method for preparing a highly active OER electrocatalyst for hydrogen production by water electrolysis, comprising the following steps:
[0086] 1. Accurately weigh 10 mg of commercially available nano TiO2 powder and add it to 15 mL of deionized water, then ultrasonically disperse for 15 min;
[0087] 2. After preheating the above dispersion at 100℃ for 15 min, add the pre-prepared K2IrCl6 aqueous solution so that the mass ratio of Ir to TiO2 is 5:1, and then react at 100℃ for 24 h.
[0088] 3. After the reaction is complete, the mixture is allowed to cool naturally to room temperature, then centrifuged and washed four times with deionized water to obtain a highly active OER electrocatalyst.
[0089] The current density of the OER electrocatalyst prepared in this example at a potential of 1366 mV vs. SCE is shown in Table 1.
[0090] Implementation 10:
[0091] 1. Accurately weigh 10 mg of commercially available nano TiO2 powder and add it to 15 mL of deionized water, then ultrasonically disperse for 15 min;
[0092] 2. After preheating the above dispersion at 100℃ for 15 min, add the pre-prepared IrCl4 aqueous solution so that the mass ratio of Ir to TiO2 is 9:1, and then react at 100℃ for 24 h.
[0093] 3. After the reaction is complete, the mixture is allowed to cool naturally to room temperature, then centrifuged and washed four times with deionized water to obtain a highly active OER electrocatalyst.
[0094] The current density of the OER electrocatalyst prepared in this example at a potential of 1366 mV vs. SCE is shown in Table 1.
[0095] Implementation 11:
[0096] This embodiment provides a method for preparing a highly active OER electrocatalyst for hydrogen production by water electrolysis, comprising the following steps:
[0097] 1. Accurately weigh 10 mg of commercially available nano TiO2 powder and add it to 5 mL of deionized water, then ultrasonically disperse for 15 min;
[0098] 2. After preheating the above dispersion at 100℃ for 15 min, add the pre-prepared (NH4)2IrCl6 aqueous solution so that the mass ratio of Ir to TiO2 is 1:1, and then react at 100℃ for 24 h.
[0099] 3. After the reaction is complete, the mixture is allowed to cool naturally to room temperature, then centrifuged and washed four times with deionized water to obtain a highly active OER electrocatalyst.
[0100] The current density of the OER electrocatalyst prepared in this example at a potential of 1366 mV vs. SCE is shown in Table 1.
[0101] Comparative Example 1:
[0102] Without adding an inducing carrier, the pre-prepared H₂IrCl₆ aqueous solution was heated at 100-200℃ for 12-48 hours and then naturally cooled to room temperature. Upon observation, the H₂IrCl₆ aqueous solution only changed from its initial brownish-yellow color to a light yellow, and no precipitate was formed. This indicates that iridium salts do not transform into solid precipitates without an inducing carrier.
[0103] Comparative Example 2:
[0104] This comparative example provides a method for preparing an OER electrocatalyst, comprising the following steps:
[0105] 1. Accurately weigh 10 mg of commercially available nano TiO2 powder and add it to 5 mL of deionized water, then ultrasonically disperse for 15 min;
[0106] 2. After preheating the above dispersion at 80℃ for 15 min, add the pre-prepared H2IrCl6 aqueous solution so that the mass ratio of Ir to TiO2 is 1:9, and then react at 80℃ for 24 h.
[0107] 3. After the reaction was completed, the mixture was allowed to cool naturally to room temperature, then centrifuged and washed four times with deionized water to obtain the control catalyst.
[0108] Figure 4This is a comparison of the OER polarization curves of the comparative catalyst prepared in Comparative Example 2 before and after electrochemical oxidation in an O2-saturated 0.1M HClO4 solution. The electrochemical oxidation conditions were: 60 cycles of potentiodynamic scanning at a scan rate of 50 mV / s, with a potentiodynamic scanning range of -274 to 1136 to -274 mV vs. SCE; the OER polarization curve testing conditions were: a linear scan rate of 5 mV / s, a potential scan range of 800 to 1366 mV vs. SCE, and a forward scan. The graph shows that the comparative catalyst exhibits very low oxygen evolution activity when directly tested for OER polarization, but only after electrochemical oxidation does it possess considerable OER activity. This indicates that below 100℃, iridium salts do not transform into iridium hydroxyoxide with high OER activity.
[0109] Table 1. Comparison of current densities at 1366 mV vs. SCE potential between the catalysts of Examples 1-11 and commercial iridium oxide catalysts.
[0110] Example 1 9.3 Example 2 8.6 Example 3 8.3 Example 4 8.5 Example 5 8.7 Example 6 8.2 Example 7 8.8 Example 8 8.4 Example 9 7.5 Example 10 6.8 Example 11 5.6 Commercial iridium oxide 3.2
Claims
1. A highly active OER electrocatalyst, characterized in that, The highly active OER electrocatalyst uses iridium hydroxyoxide as the active component; iridium hydroxyoxide is in the form of nanoparticles ≤5 nanometers, which are dispersed and deposited on the surface of the induction support in the form of single particles, or aggregated together in the form of multiple nanoparticles to form aggregates covering the surface of the induction support. Using transition metal oxides and / or nitrides as inducing supports, the iridium salt is converted into iridium hydroxyoxide and deposited on the surface of the inducing support through the induced hydrolysis of the inducing support, thus obtaining the OER electrocatalyst. The preparation method of the OER electrocatalyst includes the following steps: 1) Add the inducing carrier to water and disperse it evenly to obtain the first dispersion; 2) Preheat the first dispersion at 100-300℃ to obtain the second dispersion; 3) Add the Ir precursor solution to the second dispersion and react at 100-300℃ for at least 1 hour to obtain the third dispersion; 4) Separate the solids from the third dispersion to obtain the highly active OER electrocatalyst; In step 1), the transition metal oxide is at least one of TiO2, Ti4O7, Nb2O5, and Ta2O5, and the transition metal nitride is at least one of TiN, NbN, and TaN; In step 3), the Ir precursor solution is an aqueous solution of a soluble salt or soluble acid of Ir; the mass ratio of Ir in the Ir precursor solution to the inducing carrier in the second dispersion is 1:9-9:
1.
2. The highly active OER electrocatalyst according to claim 1, characterized in that, The dispersion described in step 1) includes ultrasonic dispersion and stirring dispersion; the concentration of the first dispersion is 0.1-10 mg / mL.
3. The highly active OER electrocatalyst according to claim 1, characterized in that, In step 2), the preheating temperature is 100-200℃; the preheating time is more than 10 minutes.
4. The highly active OER electrocatalyst according to claim 1, characterized in that, In step 3), the reaction temperature is 100-200℃ and the reaction time is at least 6 hours.
5. The highly active OER electrocatalyst according to claim 1, characterized in that, In step 4), the separation method includes filtration and centrifugation. The separated solids are washed with water and dried to obtain a highly active OER electrocatalyst.
6. The application of the highly active OER electrocatalyst according to any one of claims 1-5 in hydrogen production by water electrolysis.
7. The application according to claim 6, characterized in that, The highly active OER electrocatalyst described herein serves as an anode oxygen evolution catalyst.