Anode slurry, preparation method therefor, and use thereof

Abstract

Disclosed are an anode slurry, a preparation method therefor, and a use thereof. The present invention provides a method for preparing anode slurry C, which comprises the following steps: step 1, mixing an iridium catalyst, a perfluorosulfonic acid resin dispersion, and a solvent to obtain slurry A; step 2, adding a platinum precursor to slurry A to obtain slurry B; and step 3, reacting slurry B at 50-90 °C to prepare anode slurry C. In the present invention, by means of directly adding a water-soluble platinum precursor into an anode oxidation iridium catalyst slurry, the dispersion of platinum and the hydrogen removal capability in oxygen per unit mass of platinum are significantly improved.

Description

Anode slurry, preparation method and application thereof

[0001] The present application claims priority from Chinese patent application 2024113328770 with a filing date of 2024 / 9 / 24. The present application incorporates the entire text of the aforementioned Chinese patent application. TECHNICAL FIELD

[0002] The present application belongs to the field of PEM electrolysis of water, and relates to an anode slurry, a preparation method and application thereof. BACKGROUND

[0003] PEM electrolysis of water to produce hydrogen is the mainstream direction of current green hydrogen development, which has the characteristics of high energy efficiency, high gas purity, and strong power adaptability. In order to promote large-scale application, in addition to factors such as energy consumption, service life and cost, it is also necessary to focus on the safety problem of high hydrogen content in oxygen (oxygen hydrogen) caused by hydrogen permeation from the cathode to the anode, especially under high hydrogen outlet pressure.

[0004] In order to reduce the hydrogen content in oxygen, one method is to add platinum to the anode to eliminate oxygen hydrogen, usually by physically mixing platinum with iridium oxide to prepare the anode. The amount of platinum added should be appropriate, and too much platinum will cause a significant decrease in the performance of the membrane electrode and an increase in cost. Therefore, it is necessary to improve the dispersion of platinum in the anode as much as possible, improve the oxygen hydrogen elimination capacity of unit mass platinum, ensure the oxygen hydrogen elimination performance while reducing the amount of platinum, and avoid the reduction of the water electrolysis performance of the membrane electrode and the increase of the material cost.

[0005] SUMMARY

[0006] The present application is to overcome the problem that the dispersion of platinum in the anode and the oxygen hydrogen elimination capacity of unit mass platinum cannot be sufficiently improved in the prior art. An anode slurry, a preparation method and application thereof are provided. The present application significantly improves the dispersion of platinum and the oxygen hydrogen elimination capacity of unit mass platinum by directly adding a water-soluble platinum precursor to the anode iridium oxide catalyst slurry.

[0007] The present application solves the above technical problems by adopting the following technical solutions.

[0008] The present application provides a preparation method of an anode slurry C, which comprises the following steps:

[0009] Step 1, mixing iridium catalyst, perfluorosulfonic acid resin dispersion and solvent to obtain slurry A;

[0010] Step 2, adding platinum precursor to slurry A to obtain slurry B;

[0011] Step 3, preparing anode slurry C by reacting slurry B at 50-90℃.

[0012] In some embodiments, in step 1, the iridium catalyst is iridium oxide or iridium black; for example, iridium oxide.

[0013] In some embodiments, in step 1, the perfluorosulfonic acid resin dispersion is a 20wt% perfluorosulfonic acid resin dispersion (wt% is the mass percentage, which refers to the proportion of a substance in a mixture).

[0014] In some embodiments, in step 1, the solvent is water and an alcohol solvent; the alcohol solvent can be one or more of ethanol, isopropanol, n-propanol, ethylene glycol, and glycerol; for example, ethanol.

[0015] In some embodiments, in step 1, the mass ratio of the iridium catalyst to the perfluorosulfonic acid resin dispersion is 1:(1-2); preferably 1:1.25.

[0016] In some embodiments, in step 1, the molar volume ratio of the iridium catalyst to the solvent is (1.5-2.5)mmol / ml:1; preferably 1.93mmol / ml.

[0017] In some embodiments, in step 2, the platinum precursor is one or more of chloroplatinic acid, potassium chloroplatinate, potassium chloroplatous acid, dinitrosoplatinum diammine, and platinum nitrate; for example, potassium chloroplatous acid or dinitrosoplatinum diammine.

[0018] In some embodiments, the molar ratio of the iridium catalyst in step 1 to the platinum precursor in step 2 is 1:(0.04-0.06); preferably 1:0.056.

[0019] In some embodiments, in step 3, the reaction temperature of the reaction is 60°C.

[0020] In some embodiments, in step 3, the reaction time of the reaction is 1-5h; for example, 2h.

[0021] In some embodiments, in step 3, the reaction must be carried out under inert gas conditions, which can be one or both of argon or nitrogen; preferably nitrogen.

[0022] In some embodiments, the preparation method of the anode slurry C is to mix the iridium oxide, the perfluorosulfonic acid resin dispersion, and the solvent to obtain slurry A; then the platinum precursor is added to slurry A and dispersed uniformly to obtain slurry B; the slurry B is reacted at 50-90°C to obtain the anode slurry C.

[0023] The present application also provides an anode slurry C; the anode slurry C is prepared by the preparation method of the anode slurry C as described above.

[0024] The present application also provides an application of the anode slurry C in the preparation of a platinum-containing anode, wherein the anode slurry C is as described in any of the embodiments of the present application.

[0025] The present application also provides a preparation method of a platinum-containing anode, comprising the following steps: coating the anode slurry C as described above on a substrate film to obtain the platinum-containing anode.

[0026] In some embodiments, the substrate film is a polytetrafluoroethylene film, a polyethylene terephthalate film with a release layer, or a polyimide film with a release layer; for example, a polytetrafluoroethylene film.

[0027] In some embodiments, in the preparation method of the platinum-containing anode, the anode slurry C is used to prepare the platinum-containing anode on the substrate film by a coating method or an ultrasonic spraying method; preferably, the coating method.

[0028] The present application also provides a platinum-containing anode prepared by the preparation method of the platinum-containing anode as described above.

[0029] The present application also provides a preparation method of a membrane electrode, comprising the following steps: combining a platinum-containing anode, a cathode, and a proton exchange membrane to obtain a membrane electrode; wherein the platinum-containing anode is as described in any of the embodiments of the present application.

[0030] In some embodiments, the membrane electrode is immersed in an acid solution for 10-48 hours; for example, 12 hours.

[0031] In some embodiments, the cathode is a conventional cathode in the art, preferably, the cathode comprises carbon-supported platinum, a perfluorosulfonic acid resin dispersion, and a polytetrafluoroethylene film.

[0032] In some embodiments, in the cathode, the perfluorosulfonic acid resin dispersion is a 20wt% perfluorosulfonic acid resin dispersion.

[0033] In some embodiments, in the cathode, the platinum content in the carbon-supported platinum is 40wt%.

[0034] In some embodiments, the cathode contains a solvent A, wherein the solvent A is water and an alcohol solvent; the alcohol solvent can be one or more of ethanol, isopropanol, n-propanol, ethylene glycol, and glycerol; for example, ethanol.

[0035] In some embodiments, in the cathode, the mass ratio of the carbon-supported platinum to the perfluorosulfonic acid resin dispersion is 1:(1-2); preferably, 1:1.7.

[0036] In some embodiments, the mass-volume ratio of the carbon-supported platinum to the solvent A in the cathode is (0.12-0.2) g / mL; preferably 0.16 g / mL.

[0037] In some embodiments, after the carbon-supported platinum, the perfluorosulfonic acid resin dispersion, and the solvent A are uniformly dispersed by shearing, the cathode is prepared on a polytetrafluoroethylene film by a coating method or an ultrasonic spraying method; preferably by a coating method.

[0038] In some embodiments, the components of the cathode are the carbon-supported platinum, the perfluorosulfonic acid resin dispersion, the polytetrafluoroethylene film, and the solvent.

[0039] In some embodiments, the proton exchange membrane is a conventional proton exchange membrane in the art, preferably a proton exchange membrane with a thickness of 80-250 microns.

[0040] In some embodiments, the acid solution is one or more of a sulfuric acid solution, a perchloric acid solution, a sulfurous acid solution, a formic acid solution, a nitric acid solution, or an acetic acid solution; preferably a sulfuric acid solution, for example, a 0.5 M sulfuric acid solution.

[0041] In some embodiments, the area of the platinum-containing anode is 50 cm 2 .

[0042] In some embodiments, the area of the cathode is 50 cm 2 .

[0043] In some embodiments, the membrane electrode further comprises a post-treatment step of washing with water, for example, washing with deionized water for 5 times.

[0044] The present application also provides a membrane electrode prepared by the method for preparing a membrane electrode as described above.

[0045] The present application also provides a platinum-containing anode for use in an electrolytic water device; the platinum-containing anode is as described in any of the embodiments of the present application.

[0046] In some embodiments, the electrolytic water device comprises a proton exchange membrane electrolytic water device.

[0047] In the present application, 1 mol of iridium catalyst is taken as one portion.

[0048] On the basis of not violating the common sense in the art, the above-mentioned preferred conditions can be combined arbitrarily, thereby obtaining each preferred example of the present application.

[0049] The reagents and raw materials used in the present application are commercially available.

[0050] The positive and progressive effects of this invention are as follows: By directly adding a water-soluble platinum precursor to the iridium oxide catalyst slurry, this invention significantly improves the dispersion of platinum and the oxygen hydrogen removal capacity per unit mass of platinum, providing a new approach for the design and preparation of anodes with oxygen hydrogen removal function, and has broad application prospects in the field of water electrolysis. Attached Figure Description

[0051] Figure 1 is a transmission electron microscope image of the iridium oxide / platinum catalyst in Example 2;

[0052] Figure 2 is a magnified view of section a in the transmission electron microscope image of the iridium oxide / platinum catalyst in Example 2;

[0053] Figure 3 is a magnified view of part b in the transmission electron microscope image of the iridium oxide / platinum catalyst in Example 2;

[0054] Figure 4 shows the elemental distribution of the iridium oxide / platinum catalyst in Example 2;

[0055] Figure 5 shows the X-ray photoelectron spectrum of Ir in the iridium oxide / platinum catalyst;

[0056] Figure 6 shows the polarization curves of the membrane electrodes corresponding to Example 1, Example 2, Comparative Example 1 and Comparative Example 2 at 65°C;

[0057] Figure 7 shows the hydrogen content in oxygen on the anode side of the electrolytic cell under different current densities in Example 2. Detailed Implementation

[0058] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0059] Example 1

[0060] The preparation method of the platinum-containing anode in this embodiment is as follows:

[0061] S1. Weigh out 1.2 g (5.35 mmol) of iridium oxide and 1.5 g of perfluorosulfonic acid resin dispersion (Nafion). TM D2020 (resin content 20wt%), 1.5g (1.5ml) of deionized water and 1g (1.27ml) of ethanol were placed in a beaker and initially mixed to obtain slurry A. Then, 0.13g (0.3mmol) of potassium chloroplatinate was weighed and added to the above slurry A and dispersed evenly to obtain slurry B. Nitrogen gas was then introduced into the slurry to remove air.

[0062] S2. Place the slurry B obtained in S1 in a water bath, heat it to 60°C and maintain the temperature for 2 hours to obtain slurry C.

[0063] S3. The slurry C obtained in S2 is sheared and dispersed evenly, and then coated onto a polytetrafluoroethylene membrane to form a platinum-containing anode.

[0064] Fabrication of membrane electrodes:

[0065] S4. Weigh out 0.7g of carbon-supported platinum (platinum content 40wt%) and 1.2g of perfluorosulfonic acid resin dispersion (Nafion). TM D2020 (resin content 20wt%), 3g (3ml) of deionized water and 1g (1.27ml) of ethanol were placed in a beaker and dispersed evenly by shearing to obtain a cathode slurry. Then, the cathode was fabricated on a polytetrafluoroethylene membrane by coating.

[0066] S5. Cut the platinum-containing anode and cathode into 50cm pieces respectively. 2 The square pieces, then with the proton exchange membrane (Nafion) TM The membrane electrode (MEA) was fabricated by hot pressing transfer. The MEA was then immersed in a 0.5M sulfuric acid solution for 12 hours and finally rinsed with deionized water 5 times.

[0067] Example 2

[0068] The preparation method of the platinum-containing anode in this embodiment is as follows:

[0069] S1. Weigh out 1.2g of iridium oxide (5.35mmol) and 1.5g of perfluorosulfonic acid resin dispersion (20wt% Nafion). TM 1.5 g (1.5 ml) of deionized water and 1 g (1.27 ml) of ethanol were placed in a beaker and mixed initially to obtain slurry A. Then, 0.1 g (0.3 mmol) of dinitrosodiamineplatin was weighed and added to the above slurry A and dispersed evenly to obtain slurry B. Nitrogen gas was then introduced into the slurry to remove air.

[0070] S2. Place the slurry B obtained in S1 in a water bath, heat it to 60°C and maintain the temperature for 2 hours to obtain slurry C.

[0071] S3. The slurry C obtained in S2 is sheared and dispersed evenly, and then coated onto a polytetrafluoroethylene membrane to form a platinum-containing anode.

[0072] Cathode preparation:

[0073] S4. Weigh out 0.7g of carbon-supported platinum (platinum content 40wt%) and 1.2g of perfluorosulfonic acid resin dispersion (Nafion). TMD2020 (resin content 20wt%), 3g deionized water and 1g ethanol were placed in a beaker and sheared and dispersed evenly to obtain a cathode slurry, which was then coated onto a polytetrafluoroethylene membrane to form a cathode.

[0074] Fabrication of membrane electrodes:

[0075] S5. Cut the platinum-containing anode and cathode into 50cm pieces respectively. 2 The square pieces, then with the proton exchange membrane (Nafion) TM The membrane electrode (MEA) was fabricated by hot pressing transfer. The MEA was then immersed in a 0.5M sulfuric acid solution for 12 hours and finally rinsed with deionized water 5 times.

[0076] Figures 1-3 and 4 are transmission electron microscopy (TEM) images and elemental distribution maps of the iridium oxide / platinum catalyst after step S2 in this embodiment, respectively. Analysis of the results in the figures shows that the method of this patent can achieve a high and uniform dispersion of platinum on the iridium oxide surface, thereby significantly improving the utilization rate of platinum.

[0077] Figure 5 shows the X-ray photoelectron spectrum of iridium in the iridium oxide / platinum catalyst after the S2 step in this embodiment. Analysis of the results in the figure shows that the binding energy of iridium in iridium oxide / platinum has shifted compared to the binding energy of iridium in iridium oxide, indicating that there is an electronic interaction between platinum and iridium oxide, which may be beneficial to improving the catalyst's ability to eliminate hydrogen from oxygen.

[0078] Comparative Example 1

[0079] The conventional anode preparation method for this comparative example is as follows:

[0080] S1. Weigh out 1.2g of iridium oxide and 1.5g of perfluorosulfonic acid resin dispersion (20wt% Nafion). TM 1.5g of deionized water and 1g of ethanol were placed in a beaker and dispersed evenly by shearing to obtain slurry A. The obtained slurry A was then coated onto a polytetrafluoroethylene membrane to form an anode.

[0081] Cathode preparation:

[0082] S2. Weigh out 0.7g of carbon-supported platinum (platinum content 40wt%) and 1.2g of perfluorosulfonic acid resin dispersion (Nafion). TM D2020 (resin content 20wt%), 3g deionized water and 1g ethanol were placed in a beaker and sheared and dispersed evenly to obtain a cathode slurry, which was then coated onto a polytetrafluoroethylene membrane to form a cathode.

[0083] Fabrication of membrane electrodes:

[0084] S3, cut the anode and cathode into 50cm 2 square pieces respectively, then make a membrane electrode by hot-press transfer printing with a proton exchange membrane (Nafion TM N115), then immerse the membrane electrode in a 0.5M sulfuric acid solution for 12 hours, and finally wash the membrane electrode with deionized water for 5 times.

[0085] Comparative Example 2

[0086] The preparation method of the anode added with platinum black is as follows:

[0087] S1, take 1.2g of iridium oxide, 1.5g of a perfluorosulfonic acid resin dispersion solution (20wt% Nafion TM ), 1.5g of deionized water and 1g of ethanol, mix them in a beaker to obtain slurry A, then take 0.06g of platinum black and add it to the slurry A, and uniformly disperse it by shearing to obtain slurry B. The prepared slurry B is made into an anode on a polytetrafluoroethylene film by coating.

[0088] Preparation of the cathode:

[0089] S2, take 0.7g of platinum on carbon (platinum content 40wt%), 1.2g of a perfluorosulfonic acid resin dispersion solution (Nafion TM D2020, resin content 20wt%), 3g of deionized water and 1g of ethanol, mix them in a beaker to obtain a cathode slurry, and then make a cathode on a polytetrafluoroethylene film by coating.

[0090] Preparation of the membrane electrode:

[0091] S3, cut the anode and cathode into 50cm 2 square pieces respectively, then make a membrane electrode by hot-press transfer printing with a proton exchange membrane (Nafion TM N115), then immerse the membrane electrode in a 0.5M sulfuric acid solution for 12 hours, and finally wash the membrane electrode with deionized water for 5 times.

[0092] Example 1

[0093] 1. Test of the electrical performance of the anode in a proton exchange membrane electrolysis cell and the hydrogen elimination effect in oxygen, which includes the following steps:

[0094] 1) Assembly of the electrolysis cell and test of the electrical performance. Take one of each of the electrolytic water membrane electrodes prepared in Example 1, Example 2, Comparative Example 1 and Comparative Example 2, and assemble them in turn into the same set of electrolysis cell test device (self-made test device, composed of end plate, conductive plate, sealing element, screw fastener) for electrical performance test. The test conditions are as follows: deionized water is passed through the anode at a flow rate of 1.6mL·cm-2 ·min -1 , the pressure was normal pressure; the cathode pressure was normal pressure; the test temperature was 65℃; the constant current test was carried out for 2 min under each current density value, the current and voltage values were recorded, and the polarization curve was drawn. The relevant test results are shown in FIG. 6 and Table 1, and the electrical properties of the four membrane electrodes are close, indicating that the addition of a small amount of platinum catalyst to the anode has little effect on the electrical properties.

[0095] 2) Anode hydrogen elimination effect test on oxygen in the anode side of the electrolytic cell under different pressures. After completing the test in step 1), the hydrogen elimination effect test on oxygen in the anode side of the electrolytic cell under different pressures was carried out for the four membrane electrodes in turn. Among them, the test conditions are as follows: the anode passes deionized water, the flow rate is 1.6 mL·cm -2 ·min -1 ; the pressure of the anode and the cathode is controlled to be 0.1, 0.5 and 1.0 MPa in turn; the test temperature is 65℃; the current value is set to 75 A, and the constant current is run; the hydrogen gas concentration sensor is used to measure the hydrogen content in oxygen, and the hydrogen content in oxygen at 20 min under each pressure is recorded. The relevant test results are shown in Table 2, and it can be seen that under all pressures, the anode directly added with platinum black catalyst can reduce the hydrogen content in oxygen to a certain extent, but the effect is general, while the anode prepared by using the patent of the application can significantly reduce the hydrogen content in oxygen. For example, under the pressure of 1.0 MPa, the hydrogen content in oxygen corresponding to the conventional anode (comparative example 1), the anode added with platinum black (comparative example 2), the anode with in-situ grown platinum (examples 1 and 2) is 10100, 8230, 580 and 80 ppm in turn.

[0096] 3) Anode hydrogen elimination effect test on oxygen in the anode side of the electrolytic cell under different current densities. In order to more comprehensively evaluate the hydrogen elimination effect of the anode of the application on oxygen, the hydrogen elimination effect test on oxygen in the anode side of the electrolytic cell under different current densities was carried out for the membrane electrode corresponding to example 2. Among them, the test conditions are as follows: the anode passes deionized water, the flow rate is 1.6 mL·cm -2 ·min -1 , the pressure is normal pressure; the cathode pressure is normal pressure; the test temperature is 65℃; the hydrogen content in oxygen is measured by using the hydrogen gas concentration sensor, and the hydrogen content in oxygen at 20 min under each current density value is recorded, and the hydrogen content in oxygen-current density curve is drawn. FIG. 7 is the hydrogen content in oxygen in the anode side of the electrolytic cell under different current densities of example 2. It can be seen from FIG. 7 that in the range of 0.15-2.0 Acm -2 , the hydrogen content in oxygen is relatively low, below 150 ppm.

[0097] Table 1 Electrical properties of the membrane electrodes corresponding to the anodes

[0098] Table 2 Oxygen hydrogen content of the membrane electrodes corresponding to the anodes under different pressures

[0099] The above description is only the preferred embodiment of the present application, and is not any form and substantial limitation of the present application. It should be pointed out that, for ordinary skilled in the art, without departing from the method of the present application, a number of improvements and supplements can also be made, which should be considered as the protection scope of the present application. For those skilled in the art, without departing from the spirit and scope of the present application, some changes, modifications and equivalent changes made by using the above disclosed technical content are equivalent embodiments of the present application; at the same time, any equivalent changes, modifications and evolution made according to the essential technology of the present application to the above embodiments are still within the scope of the technical solutions of the present application.

Claims

1. A method for preparing an anode slurry C, comprising the following steps: Step 1, mixing iridium catalyst, perfluorosulfonic acid resin dispersion and solvent to obtain slurry A; Step 2, adding platinum precursor into slurry A to obtain slurry B; Step 3, reacting slurry B at 50-90℃ to prepare anode slurry C.

2. The production process according to claim 1; characterized in that, It meets one or more of the following conditions: (1) In step 1, the iridium catalyst is iridium oxide or iridium black; for example, iridium oxide; (2) In step 1, the perfluorosulfonic acid resin dispersion is 20wt% perfluorosulfonic acid resin dispersion; (3) In step 1, the solvent is water and alcohol solvent; the alcohol solvent can be one or more of ethanol, isopropanol, n-propanol, ethylene glycol and glycerol; for example, ethanol; (4) In step 1, the mass ratio of the iridium catalyst to the perfluorosulfonic acid resin dispersion is 1: (1-2); preferably 1:1.25; (5) In step 1, the molar volume ratio of the iridium catalyst to the solvent is (1.5-2.5) mmol / ml:1; preferably 1.93 mmol / ml; (6) In step 2, the platinum precursor is one or more of chloroplatinic acid, potassium chloroplatinate, potassium chloroplatinite, dinitrosyl diaminoplatinum and platinum nitrate; for example, potassium chloroplatinite or dinitrosyl diaminoplatinum; (7) The molar ratio of the iridium catalyst in step 1 to the platinum precursor in step 2 is 1: (0.04-0.06); preferably 1:0.056; (8) In step 3, the reaction temperature of the reaction is 60℃; (9) In step 3, the reaction time of the reaction is 1-5h; for example, 2h; and (10) In step 3, the reaction must be under inert gas conditions, which can be one or both of argon or nitrogen; preferably nitrogen.

3. The production process according to claim 1; characterized in that, The method for preparing the anode slurry C is mixing iridium oxide, perfluorosulfonic acid resin dispersion and solvent to obtain slurry A; then adding platinum precursor into slurry A and dispersing uniformly to obtain slurry B; reacting slurry B at 50-90℃ to obtain anode slurry C; the iridium oxide, the perfluorosulfonic acid resin dispersion, the solvent and the platinum precursor are as described in claim 1 or 2.

4. An anode slurry C characterized by, The anode slurry C is prepared by the method for preparing anode slurry C according to any one of claims 1-3.

5. Use of an anode slurry C for the preparation of a platinum-containing anode, characterized in that The anode slurry C is as described in claim 4.

6. A method of producing a platinum-containing anode, characterized by, It comprises the following steps: coating the anode slurry C according to any one of claims 1-3 onto a substrate film to prepare a platinum-containing anode.

7. The method of claim 6, wherein the platinum-containing anode is prepared by, It meets one or two of the following conditions: (1) The substrate film is a polytetrafluoroethylene film, a polyethylene terephthalate film with a release layer or a polyimide film with a release layer; for example, a polytetrafluoroethylene film; (2) In the method for preparing the platinum-containing anode, the anode slurry C is prepared into the platinum-containing anode on the substrate film by coating method or ultrasonic spraying method; preferably coating method.

8. A platinum-containing anode, characterized by, It is prepared by the method for preparing a platinum-containing anode according to claim 6 or 7.

9. Use of a platinum-containing anode in an electrolytic water device; the platinum-containing anode is as described in claim 8.

10. Use according to claim 9, characterized in that, The water electrolysis device includes a proton exchange membrane water electrolysis device.

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