Ir / IrO2 catalyst, preparation method and application thereof, and membrane electrode
Ir/IrO2 catalysts were prepared by solid-state calcination and their electronic structure was controlled, which solved the problem of poor stability of Ir-based catalysts in acidic water electrolysis. This resulted in highly active and stable Ir/IrO2 catalysts suitable for oxygen evolution reaction in acidic water electrolysis and proton exchange membrane water electrolysis.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI H RAY S & T CO LTD
- Filing Date
- 2025-12-22
- Publication Date
- 2026-04-14
AI Technical Summary
Existing Ir-based catalysts exhibit poor stability and low activity in acidic water electrolysis, making it difficult to maintain stability under high current and high voltage conditions.
Ir/IrO2 catalysts were prepared by solid-state calcination. By adjusting the calcination temperature and atmosphere and using inorganic acid salts as barrier agents, the electronic structure of IrO2 was controlled, and nanoscale dispersed Ir/IrO2 catalysts were synthesized.
This improved the activity and stability of the Ir/IrO2 catalyst, resulting in a low overpotential and stable operation over a long period at high current densities, thus enhancing the catalytic performance of the membrane electrode.
Smart Images
Figure CN121853010A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of water electrolysis for hydrogen production technology, specifically to an Ir / IrO2 catalyst, its preparation method and application, and a membrane electrode. Background Technology
[0002] With the rapid development of low-carbon economy and renewable energy, hydrogen energy has received widespread attention as an ideal energy carrier and efficient energy storage technology. Proton exchange membrane (PEM) water electrolysis for hydrogen production is a key research focus and the most promising hydrogen production technology due to its advantages such as cleanliness, high current density, high electrolysis efficiency, and high hydrogen purity. In PEM water electrolysis for hydrogen production, high-performance catalysts are limited to precious metals; therefore, cost reduction and efficiency improvement are crucial for the large-scale application of PEM water electrolysis for hydrogen production. Currently, iridium-based and ruthenium-based catalysts are mainly used in acidic water electrolysis. However, ruthenium-based catalysts are easily dissolved under acidic and high-potential conditions, leading to catalyst deactivation, while iridium-based catalysts have relatively low activity. Therefore, simultaneously improving catalyst activity and stability is a current research focus and hot topic.
[0003] Currently, the main method to simultaneously improve activity and stability is elemental doping. For example, Peng et al. reported a Ru1−xMxO2 (M=Sb, In, and Sn) bimetallic solid solution oxide, which constructs a highly asymmetric Ru-O-Sb unit with a strong electronic conjugation effect, greatly shortening the spatial distance between Ru and Sb sites and improving the overall bonding strength. The optimized Ru... 0.8 Sb 0.2 O2 solid solution at 10 mA cm -2 Under these conditions, it exhibits an ultra-low overpotential of 160 mV and achieves a record-breaking stability of 1100 hours in acidic electrolytes. Yong-Tae Kim reported the formation of Ir via rapid desmotrinization. 25 Os 75 The highly conductive nanoporous core-shell structure of @IrO2 exhibits an unusual balance between oxygen evolution activity and stability (quantified by the activity-stability factor). Based on this metric, compared to conventional iridium-based oxide materials, dealloyed IrO2... 25 Os 75 The activity-stability factor of the nanoporous Ir / IrO2 morphology of @IrO2 is increased by about 30 times. However, this regulation is often effective in three-electrode systems, but the stability of the dopant element is difficult to maintain under high current and high voltage conditions. Summary of the Invention
[0004] The technical problem this invention aims to solve is to overcome the defects of poor stability and low activity of catalysts in the prior art, and to provide an Ir / IrO2 catalyst, its preparation method, its application, and a membrane electrode. When the Ir / IrO2 catalyst of this invention is applied to the oxygen evolution reaction in acidic water electrolysis, it exhibits a low overpotential and high stability. When the membrane electrode prepared using the Ir / IrO2 catalyst of this invention is applied to the proton exchange membrane water electrolysis catalytic reaction, it exhibits high activity and stability.
[0005] The present invention solves the above-mentioned technical problems through the following technical solution:
[0006] A method for preparing an Ir / IrO2 catalyst, the method comprising the following steps:
[0007] The Ir / IrO2 catalyst is obtained by calcining a mixture including an iridium source and an inorganic acid salt in the solid phase.
[0008] Preferably, the calcination atmosphere includes one or more of air, argon, carbon dioxide, hydrogen, and nitrogen, such as carbon dioxide or nitrogen.
[0009] Preferably, the iridium source includes one or more of IrCl3·xH2O, IrCl3, H2IrCl6, K3IrCl6, and K2IrCl6, such as K2IrCl6.
[0010] Preferably, the inorganic acid salt includes one or more combinations of KNO3, NaNO3, K2CO3, Na2CO3, K2SO4, Na2SO4, NaCl and KCl, such as K2CO3.
[0011] Preferably, the mixture of the iridium source and the inorganic acid salt is obtained by thoroughly grinding the iridium source and the inorganic acid salt. More preferably, the mixture of the iridium source and the inorganic acid salt is obtained by separately weighing the iridium source and the inorganic acid salt, and then thoroughly grinding them. Generally, the iridium source is colored, the inorganic acid salt is white, and the endpoint of thorough grinding is when the colors of the iridium source and the inorganic acid salt are uniformly mixed.
[0012] The mass ratio of iridium source to inorganic acid salt can be 1:(1-10), preferably including 1:1, 1:2, 1:3, 1:5 or 1:10.
[0013] The calcination equipment can be conventional in the art, such as a tube furnace.
[0014] The preferred calcination temperature is 350-550℃, more preferably 400-500℃, for example 450℃.
[0015] Preferably, the holding time during calcination is 0.5-4 hours, for example, 1 hour.
[0016] Preferably, the heating rate from room temperature to the calcination temperature is 1-5°C / min, for example, 5°C / min.
[0017] In a preferred embodiment, the calcination conditions are as follows: the calcination atmosphere includes carbon dioxide; the calcination temperature is 350℃-550℃, the heating rate from room temperature to the calcination temperature is 1-5℃ / min, and the holding time during calcination is 0.5-4h.
[0018] The calcination atmosphere, calcination temperature, and time affect the molar ratio of Ir and IrO2 in the catalyst, thus influencing the electronic structure of Ir. The calcination temperature affects the crystallinity of the prepared catalyst; higher calcination temperatures result in higher crystallinity. However, excessively high temperatures lead to larger catalyst particle sizes and smaller active areas, while excessively low calcination temperatures result in incomplete reactions. Therefore, based on various influencing factors and through extensive creative work, the heating rate in this invention can be any value within the range of 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, etc., and can be adjusted according to actual conditions; the calcination temperature can be any value within the range of 350℃, 400℃, 500℃, 550℃, etc., and can be adjusted according to actual conditions; the holding time can be any value within the range of 0.5 h, 1 h, 2 h, 2.5 h, 3 h, etc., and can be adjusted according to actual conditions.
[0019] Preferably, the calcination process further includes conventional cooling, washing, and drying steps. The cooling operation can be conventional, such as natural cooling to room temperature, typically 20-30°C. The washing solvent preferably includes one or a combination of water, ethanol, and isopropanol, for example, water, or water and ethanol. The volume ratio of water to ethanol is preferably (0-1):(1-2), for example, 1:1. The drying operation can be conventional, such as vacuum drying. The drying temperature is preferably 50-70°C, for example, 60°C.
[0020] Preferably, the molar ratio of IrO2 to Ir in the Ir / IrO2 catalyst is 0.5-1.5, more preferably 0.8-1.4, for example 0.89, 1.08 or 1.27.
[0021] Preferably, in the Ir / IrO2 catalyst, Ir +4 With (Ir) 0 + Ir +4 The molar ratio can be 0.3-0.7, for example 0.47, 0.52 or 0.56.
[0022] Preferably, the Ir / IrO2 catalyst has a particle size of 1-6 nm, for example 2-3 nm.
[0023] Preferably, the Ir / IrO2 catalyst prepared by the method described above is used as an oxygen evolution catalyst in the acidic water electrolysis oxygen evolution reaction.
[0024] In this invention, the inventors discovered during the research and development process that calcining a mixture including an iridium source and an inorganic acid salt in the solid phase, relying on the uniform ionic environment and the electrostatic repulsion of salt ions, can avoid Ostwald ripening (i.e., particle size rearrangement and aggregation), iridium source aggregation, and inorganic acid salt residue caused by high-temperature calcination. At low temperature and low consumption, highly dispersed ultra-small nanoparticle Ir / IrO2 catalysts can be synthesized, and the active sites can be exposed to the maximum extent. This provides a good foundation for subsequent acidic water electrolysis oxygen evolution reaction and the preparation of membrane electrodes for use in proton exchange membrane water electrolysis catalytic reaction.
[0025] The present invention also provides an Ir / IrO2 catalyst, which is prepared by the above-described method for preparing an Ir / IrO2 catalyst.
[0026] This invention utilizes inorganic acid salts as barrier agents and successfully modulates the electronic structure of IrO2 by adjusting reaction temperature and atmosphere, thereby simultaneously enhancing the activity and stability of Ir-based catalysts. The final result is a nanoscale dispersed Ir / IrO2 catalyst.
[0027] Preferably, the molar ratio of IrO2 to Ir in the Ir / IrO2 catalyst is 0.5-1.5, more preferably 0.8-1.4, for example 0.89, 1.08 or 1.27.
[0028] Preferably, in the Ir / IrO2 catalyst, Ir +4 With (Ir) 0 + Ir +4 The molar ratio can be 0.3-0.7, for example 0.47, 0.52 or 0.56.
[0029] Preferably, the Ir / IrO2 catalyst has a particle size of 1-6 nm, for example 2-3 nm.
[0030] The present invention also provides an application of the Ir / IrO2 catalyst, which is used as an oxygen evolution catalyst in the acidic water electrolysis oxygen evolution reaction, wherein the Ir / IrO2 catalyst is prepared by the above-described preparation method.
[0031] The present invention also provides a membrane electrode comprising the Ir / IrO2 catalyst as described above.
[0032] The positive and progressive effects of this invention are as follows:
[0033] This invention uses inorganic acid salts as barrier agents. The iridium source and inorganic acid salts are calcined in the solid phase to obtain an Ir / IrO2 catalyst. When applied to the oxygen evolution reaction of acidic water electrolysis, the catalyst exhibits low overpotential and high stability. When the membrane electrode made using the Ir / IrO2 catalyst of this invention is applied to the proton exchange membrane water electrolysis catalytic reaction, it exhibits high activity and stability.
[0034] Preferably, by adjusting the reaction temperature and atmosphere, the electronic structure of IrO2 was successfully controlled, thereby simultaneously improving the activity and stability of the Ir-based catalyst, ultimately obtaining a uniformly dispersed Ir / IrO2 catalyst with a particle size of only about 3 nm; and this catalyst can withstand 10 mA cm⁻¹ -2 The overpotential is 270-302 mV at a current density of 10 mA cm⁻¹. -2 The constant current test showed stability for 150-400 h; the prepared Ir / IrO2 catalyst maintained high activity and stability on the membrane electrode, while exhibiting high metal utilization. The Ir / IrO2 catalyst demonstrated excellent performance in water electrolysis devices, with a current density reaching 3 A / cm². 2 The cell voltage dropped to 1.745 V. Meanwhile, Ir / IrO2 also exhibited excellent stability, with a voltage of 2 A / cm². 2 It can operate stably for 2000 hours with a decay rate of only 8.1 μV / h. Different Ir / IrO2 catalyst ratios were obtained by adjusting the reaction temperature. Analysis revealed that the OER activity is related to the Ir / IrO2 ratio, with Ir showing the best performance. 4+ / (Ir 0 +Ir 4+ The performance is optimal when the value is 0.47. Attached Figure Description
[0035] Figure 1 The diagram shows a process flow chart of the preparation method of the Ir / IrO2 catalyst in an embodiment of the present invention.
[0036] Figure 2 Part a shows the HRTEM image of the Ir / IrO2 catalyst prepared in Specific Example 1 of the present invention;
[0037] Figure 2 Part b shows the selected area electron diffraction pattern of the Ir / IrO2 catalyst prepared in Specific Example 1 of the present invention;
[0038] Figure 3 The image shown is the XPS Ir 4f spectrum of the Ir / IrO2 catalyst prepared in Examples 1 to 3 of this invention;
[0039] Figure 4 The image shown is an XRD pattern of the Ir / IrO2 catalyst prepared in Examples 1 to 3 of this invention.
[0040] Figure 5 Part a Figure 5 Part b shows the linear sweep voltammetry (LSV) curves of the Ir / IrO2 catalysts prepared in Specific Examples 1 to 3 and Comparative Example 1 of the present invention, respectively.
[0041] Figure 6 The OER activity of the Ir / IrO2 catalyst prepared in Examples 1 to 3 of this invention is shown as the relationship between Ir and Ir. 4+ / (Ir 0 +Ir 4+ Relationship change curve;
[0042] Figure 7 The graphs shown are electrochemical lifetime test results of the Ir / IrO2 catalysts prepared in Examples 1 to 3 of the present invention at 10 mA cm-2.
[0043] Figure 8 The diagram shows the polarization curve of the membrane electrode prepared in specific embodiment 4 of the present invention.
[0044] Figure 9 The figure shown is a stability test diagram of the membrane electrode prepared according to specific embodiment 4 of the present invention. Detailed Implementation
[0045] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.
[0046] The flowchart of the preparation method of the Ir / IrO2 catalyst in the following examples is shown below. Figure 1 As shown.
[0047] Example 1
[0048] This embodiment provides a method for preparing an Ir / IrO2 catalyst, which includes the following steps:
[0049] S1. Weigh 100 mg K2IrCl6 and 0.5 g K2CO3, and grind them thoroughly to obtain a mixture;
[0050] S2. Place the mixture from step S1 in a CO2 atmosphere in a tube furnace, heat it to 400°C at a heating rate of 5°C / min and hold it at that temperature for 1 hour, then let it cool naturally to room temperature to obtain a solid powder.
[0051] S3. After cooling the solid powder obtained in step S2, wash off the excess potassium carbonate with deionized water and dry it under vacuum at 60°C to obtain the Ir / IrO2 catalyst (denoted as Ir / IrO2-400).
[0052] Example 2
[0053] This embodiment provides a method for preparing an Ir / IrO2 catalyst, which differs from that in Example 1 in that: in step S3, the temperature is increased to 450°C at a heating rate of 5°C / min and held for 1 hour; other steps and methods are the same as in Example 1 and will not be repeated here (denoted as Ir / IrO2-450).
[0054] Example 3
[0055] This embodiment provides a method for preparing an Ir / IrO2 catalyst, which differs from that in Example 1 in that: in step S3, the temperature is increased to 500°C at a heating rate of 5°C / min and held for 1 hour; other steps and methods are the same as in Example 1 and will not be repeated here (denoted as Ir / IrO2-500).
[0056] Comparative Example 1
[0057] This comparative example provides a method for preparing an Ir / IrO2 catalyst. The difference between this method and that of Example 1 is that in step S1, 100 mg of K2IrCl6 and 0.5 g of K2CO3 are weighed and dispersed in 100 mL of ethanol solution, then dried and ground. Other steps and methods are the same as those in Example 1 and will not be repeated here.
[0058] Performance test results
[0059] See Figure 2 Part a Figure 2 Part b shows the high-resolution transmission electron microscope (HRTEM) image and selected area electron diffraction pattern of the Ir / IrO2-400 catalyst prepared in Example 1. As can be seen from the figure, Example 1 successfully prepared a uniformly distributed ultra-small Ir / IrO2 catalyst with a particle size of about 3 nm.
[0060] See Figure 3 The above are XPS spectra of Ir 4f in the Ir / IrO2 catalysts prepared in Examples 1 to 3. Figure 3 ( Figure 3 (Both mid-satellite peaks 1 and 2 are auxiliary peaks in the XPS fitting process.) It can be seen that the two peaks located near 61.3 eV and 64.3 eV correspond to Ir, respectively. 0 4f 7 / 2 and Ir 0 4f5 / 2 The two peaks at 62.1 eV and 65.1 eV correspond to Ir, respectively. +4 4f 7 / 2 and Ir +4 4f 5 / 2 The molar ratio of Ir to tetravalent Ir can be obtained by comparing the peak areas of 0-valent Ir and tetravalent Ir. Different Ir and IrO2 molar ratios result in different average valence states of Ir, thereby altering the electronic structure of Ir. The molar ratios of 0-valent Ir and tetravalent Ir in various embodiments are shown in Table 1 below; the molar ratios of IrO2 and Ir in various embodiments are also shown in Table 1 below.
[0061] See Figure 4 The images show the XRD patterns of the Ir / IrO2 catalysts prepared in Examples 1 to 3. According to the Scherrer equation, the particle size of the Ir / IrO2 prepared in Examples 1 to 3 is 2~3 nm.
[0062] Electrochemical performance evaluation
[0063] The Ir / IrO2 catalysts prepared in Examples 1-3 and Comparative Example 1 were applied to the acidic water electrolysis oxygen evolution reaction to evaluate their electrochemical performance. The specific methods included the following:
[0064] A1. Mix 3 mg of the catalyst, 10 μL of 5% perfluorosulfonic acid (Nafion) aqueous solution, 750 μL of isopropanol and 250 μL of ultrapure water, and sonicate for 1 h to prepare an electrochemical test ink solution.
[0065] A2. Select a glassy carbon electrode tip (GC) with a diameter of 5mm and an area of 0.196cm². 2 The electrode was polished using Al2O3 powder with particle sizes of 1.0, 0.3, and 0.05 μm on a chamois surface. The polished electrode was then ultrasonically cleaned with ultrapure water and ethanol to ensure a smooth and even surface, and allowed to air dry. 15 μL of ink solution was added to the pre-polished GC electrode, which was then allowed to air dry to create the test electrode. At this point, the Ir loading was 150 μg·cm³. -2 ;
[0066] A3. The oxygen evolution performance of the test electrode in water electrolysis was tested. Specifically, a 0.5M H2SO4 solution was placed in a five-cell electrolytic cell, and N2 was introduced for half an hour to saturate the solution. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) tests were then performed. The scan rate for the CV test was 50 mVs. -1The scan was performed until the CV curve coincided, with a voltage range of 0.7~1.5V / RHE; during linear scan testing, the scan speed was 5 mVs. -1 The scanning range was 1.2~1.7V / RHE; then, at a current density of 10mA / cm², the scanning range was... -2 Electrochemical lifetime testing was then conducted.
[0067] See test results Figure 5 and Figure 6 , Figure 5 Part a Figure 5 Part b shows the linear sweep voltammetry (LSV) curves of the Ir / IrO2 catalysts prepared in Specific Examples 1 to 3 and Comparative Example 1 of the present invention, respectively. Figure 6 The OER activity of the Ir / IrO2 catalyst prepared in Examples 1 to 3 of this invention is shown as the relationship between Ir and Ir. 4+ / (Ir 0 +Ir 4+ Relationship change curve;
[0068] Depend on Figure 6 It can be seen that the Ir / IrO2 catalysts prepared in Examples 1 to 3 have a performance of 10 mA cm⁻¹ -2 The overpotential is 270 mV-302 mV.
[0069] Figure 7 The Ir / IrO2 catalyst prepared in Examples 1 to 3 of this invention is shown at 10 mA cm⁻¹. -2 The following is a graph of electrochemical lifetime test results; by Figure 7 It can be seen that the Ir / IrO2 catalyst prepared in Example 1 has excellent stability and no significant degradation after 350 h of constant current.
[0070] The above performance data are shown in Table 1.
[0071] Table 1
[0072] Specific Implementation Example 4:
[0074] This embodiment provides a method for preparing a low-noble-metal-loading water electrolysis film electrode, the method comprising the following steps:
[0075] B1. Take 20 mg of the Ir / IrO2 catalyst prepared in Example 1, add water and isopropanol in a mass ratio of 15:15:1, then add 20% Nafion membrane aqueous solution, sonicate for 1 hour to obtain anode catalyst ink, and spray the anode catalyst ink onto the surface of proton exchange membrane (GORE 275.80).
[0076] B2. Take 20 mg of Pt / C catalyst (Pt content 60 wt%), add water and isopropanol in a mass ratio of 15:15:1, then add 20% Nafion membrane aqueous solution, where the mass of Nafion resin is 20% of the mass of Pt / C catalyst. After sonication for 1 hour, obtain cathode catalyst ink. Spray the cathode catalyst ink onto the other side of the above proton exchange membrane (GORE 275.80) to finally obtain a low noble metal loading water electrolysis membrane electrode (denoted as Ir / IrO2-0.6 mgIr / cm). 2 ).
[0077] In this embodiment, the catalyst loading in the prepared membrane electrode was obtained by gravimetric measurement, and the Ir loading in the membrane electrode was determined to be 0.6 mg / cm³. 2 .
[0078] The membrane electrode (Ir / IrO2-0.6mgIr / cm) prepared in Example 4 was used. 2 This method is applied to the catalytic reaction of proton exchange membrane water electrolysis. Each membrane electrode is placed in a small water electrolysis fixture. The anode is immersed in 65°C deionized pure water, and the entire system is kept at 65°C. The current density for water electrolysis is set to 0~3 A / cm². 2 The polarization curves of the membrane electrode for water electrolysis were obtained through testing. (See attached document.) Figure 8 As shown, by Figure 8 It can be seen that Ir / IrO2 = 0.6 mgIr / cm 2 It maintains excellent activity even with ultra-low iridium loading. The membrane electrode prepared in Example 4 has an Ir / IrO2 ratio of -0.6 mgIr / cm. 2 At 3 A / cm 2 The cell voltage at 65°C is only 1.745 V; this indicates that the membrane electrode prepared by the Ir / IrO2 catalyst in Example 1 can effectively improve the utilization rate of the water electrolysis catalyst and improve the reaction performance. The Ir / IrO2 catalyst prepared in Example 1 has high catalytic activity and high utilization rate of precious metals.
[0079] The membrane electrode (Ir / IrO2-0.6mgIr / cm) prepared in Example 4 was used. 2 This method is applied to the catalytic reaction of proton exchange membrane water electrolysis. The membrane electrodes are placed in a small water electrolysis fixture, and stability tests are conducted at 65°C. During the test, ultrapure water is passed through the anode, and the current density is set to 2 A / cm². 2 The stability test results are available in the reference section. Figure 9 As shown, by Figure 9 It can be seen that Ir / IrO2 = 0.6 mg Ir / cm2 At 2 A / cm 2 It can operate stably for at least 2000 hours with a decay of only 8.1 μV / h.
[0080] In summary, this invention utilizes inorganic acid salts as barrier agents and successfully modulates the electronic structure of IrO2 by adjusting reaction temperature and atmosphere, thereby simultaneously improving the activity and stability of Ir-based catalysts. The final result is a uniformly dispersed Ir / IrO2 catalyst with a particle size of only approximately 3 nm. Furthermore, this catalyst exhibits good performance at 10 mA cm⁻¹. -2 The overpotential is 270-302 mV at a current density of 10 mA cm⁻¹. -2 The constant current test showed stability for 150-400 h; the prepared Ir / IrO2 catalyst maintained high activity and stability on the membrane electrode, while exhibiting high metal utilization. The Ir / IrO2 catalyst demonstrated excellent performance in water electrolysis devices, with a current density reaching 3 A / cm². 2 The cell voltage dropped to 1.745 V. Meanwhile, Ir / IrO2 also exhibited excellent stability, with a voltage of 2 A / cm². 2 It can operate stably for 2000 hours with a decay of only 8.1 μV / h. Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.
[0081] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.
Claims
1. A method for preparing an Ir / IrO2 catalyst, characterized in that, The preparation method includes the following steps: The Ir / IrO2 catalyst is obtained by calcining a mixture including an iridium source and an inorganic acid salt in the solid phase.
2. The method for preparing the Ir / IrO2 catalyst according to claim 1, characterized in that, The preparation method includes one or a combination of the following conditions: (1) The iridium source includes one or more of IrCl3·xH2O, IrCl3, H2IrCl6, K3IrCl6 and K2IrCl6, such as K2IrCl6; (2) The inorganic acid salt includes one or more combinations of KNO3, NaNO3, K2CO3, Na2CO3, K2SO4, Na2SO4, NaCl and KCl, such as K2CO3; (3) The mass ratio of the iridium source to the inorganic acid salt is 1:(1-10), preferably 1:1, 1:2, 1:3, 1:5 or 1:
10.
3. The method for preparing the Ir / IrO2 catalyst according to claim 1, characterized in that, The mixture of the iridium source and the inorganic acid salt is obtained by thoroughly grinding the iridium source and the inorganic acid salt; preferably, the mixture of the iridium source and the inorganic acid salt is obtained by weighing the iridium source and the inorganic acid salt separately and then thoroughly grinding them.
4. The method for preparing the Ir / IrO2 catalyst according to claim 1, characterized in that, The preparation method includes one or a combination of the following conditions: (1) The calcination atmosphere includes one or more of air, argon, carbon dioxide, hydrogen and nitrogen, such as carbon dioxide or nitrogen; (2) The calcination temperature is 350-550℃, preferably 400-500℃, for example 450℃; (3) The heat preservation time during calcination is 0.5-4h, for example, 1h; (4) The heating rate from room temperature to the calcination temperature is 1-5℃ / min, for example 5℃ / min.
5. The method for preparing the Ir / IrO2 catalyst according to claim 1, characterized in that, The calcination process preferably also includes steps of cooling, washing, and drying; Preferably, the cooling is natural cooling to 20-30°C; The solvent used for washing preferably includes one or a combination of water, ethanol and isopropanol, such as water, or water and ethanol. The drying process is preferably vacuum drying; the drying temperature is preferably 50-70℃, for example 60℃.
6. The method for preparing the Ir / IrO2 catalyst according to claim 1, characterized in that, The preparation method includes one or a combination of the following conditions: (1) The molar ratio of IrO2 to Ir in the Ir / IrO2 catalyst is 0.5-1.5, more preferably 0.8-1.4, for example 0.89, 1.08 or 1.27; (2) In the Ir / IrO2 catalyst, Ir +4 With (Ir) 0 + Ir +4 The molar ratio is 0.3-0.7, for example 0.47, 0.52 or 0.56; (3) The particle size of the Ir / IrO2 catalyst is 1-6 nm, for example 2-3 nm.
7. An Ir / IrO2 catalyst, characterized in that, The catalyst is prepared by the method for preparing Ir / IrO2 catalyst as described in any one of claims 1-6.
8. The Ir / IrO2 catalyst according to claim 7, characterized in that, The Ir / IrO2 catalyst satisfies one or more of the following conditions: (1) The molar ratio of IrO2 to Ir in the Ir / IrO2 catalyst is 0.5-1.5, more preferably 0.8-1.4, for example 0.89, 1.08 or 1.27; (2) In the Ir / IrO2 catalyst, Ir +4 With (Ir) 0 + Ir +4 The molar ratio is 0.3-0.7, for example 0.47, 0.52 or 0.56; (3) The particle size of the Ir / IrO2 catalyst is 1-6 nm, for example 2-3 nm.
9. The application of the Ir / IrO2 catalyst as described in claim 7 or 8, characterized in that: The Ir / IrO2 catalyst is used as an oxygen evolution catalyst in the oxygen evolution reaction of acidic water electrolysis.
10. A membrane electrode, characterized in that, It includes the Ir / IrO2 catalyst as described in claim 7 or 8.