Preparation method of zirconium-loaded iridium oxide type PEMWE anode catalyst

Abstract

The invention relates to the field of catalyst preparation, and discloses a preparation method of a zirconium-loaded iridium oxide type PEMWE anode catalyst, which comprises the following steps: dispersion: putting zirconium dioxide as carrier powder to be loaded into an iridium dispersion liquid, and uniformly dispersing the zirconium dioxide in the dispersion liquid to obtain a carrier solvent mixed liquid; evaporation: uniformly drying the mixed dispersion liquid, so that the iridium precursor is uniformly distributed on the surface of the carrier; mixing: adding molten salt into the mixture, and uniformly mixing the molten salt with the loaded precursor; annealing: calcining and crystallizing the mixed reactants at high temperature to form a final product; and washing: re-dissolving the calcined and annealed powder, washing with a detergent, and drying after washing to obtain the zirconium-loaded iridium oxide catalyst. The preparation method disclosed by the invention is simple in process principle and free of complex operation and expensive consumables, and has the advantages that the consumption of iridium can be greatly reduced, and the small active particles are stabilized to prevent sintering and increase the catalytic activity.

Description

Technical Field

[0001] The invention relates to the field of catalyst preparation, and in particular to a method for preparing a zirconium-supported iridium oxide type PEMWE anode catalyst. Background Art

[0002] Hydrogen can be produced by water electrolysis using electricity from renewable energy sources, including alkaline water electrolysis (AWE), proton exchange membrane water electrolysis (PEMWE) and solid oxide electrolysis cell (SOEC). Among them, PEMWE is regarded as the most promising hydrogen production route due to its high operating current density, low ohmic loss and high hydrogen purity. Currently, the anodic oxygen evolution reaction in PEMWE heavily relies on iridium-based electrocatalysts (such as pure iridium powder and iridium oxide powder). However, the scarcity and extremely high cost of iridium have greatly affected the realization of large-scale application of PEMWE.

[0003] In addition, anodic iridium oxide catalysts usually exhibit unsatisfactory OER activity and relatively large overpotential, and show relatively low durability due to the leaching of iridium species during the OER catalysis. Therefore, the development of new, efficient, durable, and low-cost iridium-based catalysts is key to achieving practical applications of PEMWE.

[0004] Combining iridium metal oxide with other metal materials is an effective method. However, in the prior art, the preparation process of iridium oxide catalyst loaded with PEMWE anode is expensive and the consumables are high, which makes the preparation cost of iridium oxide catalyst high and inconvenient to use. In addition, the preparation process is prone to aggregation to form large particles, and the mechanical properties are poor, which affects the catalytic efficiency and durability of the catalyst. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing a zirconium-supported iridium oxide-type PEMWE anode catalyst to solve the problems in the prior art.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] The invention relates to the field of catalyst preparation, and is a method for preparing a zirconium-supported iridium oxide-type PEMWE anode catalyst, comprising the following steps:

[0008] Step 1, dispersion: adding zirconium dioxide as a carrier powder to be loaded into an iridium dispersion and uniformly dispersing it in the dispersion to obtain a carrier solvent mixed solution;

[0009] Step 2, evaporation: drying the mixed dispersion evenly to make the iridium precursor evenly distributed on the surface of the carrier;

[0010] Step 3, mixing: adding molten salt to the mixture and uniformly mixing the molten salt and the loaded precursor;

[0011] Step 4: Annealing: calcining the mixed reactants at high temperature to crystallize the final product;

[0012] Step 5, washing: re-dissolving the calcined and annealed powder, washing it with a detergent, and drying it after washing to obtain a zirconium-supported iridium oxide catalyst.

[0013] Furthermore, the raw material ratios of the components for preparing the zirconium-supported iridium oxide-type PEMWE anode catalyst are as follows:

[0014] 1 part to 2.8 parts of zirconium dioxide, 1.25 parts to 8 parts of iridium-containing solution, 500 parts to 1000 parts of dispersant, 40 parts to 80 parts of fusion salt, and 2000 parts to 4000 parts of detergent.

[0015] Furthermore, in step 1, the dispersant is selected from one or more of deionized water, ethanol, n-propanol, isopropanol, ethylene glycol, methanol, and acetone.

[0016] Furthermore, in step 1, the solute used in the iridium-containing solution is selected from one or more of chloroiridic acid, potassium chloroiridate, iridium chloride, iridium acetate, iridium acetylacetonate, iridium chloride, sodium chloroiridate, and ammonium chloroiridate.

[0017] Furthermore, in the step 2, the evaporation method is selected from one or more of low-temperature drying, vacuum drying, freeze drying, and rotary evaporation.

[0018] Furthermore, in step three, the molten salt is selected from one or more of sodium nitrate, sodium acetate, sodium citrate, sodium formate, sodium chloride, sodium nitrite, sodium carbonate, ammonium nitrate, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, polyvinyl pyrrolidone, and polyethylene glycol.

[0019] Furthermore, in step three, the mixing method of the precursor molten salt is selected from one or more of ball milling, stirring, rotary evaporation, and grinding.

[0020] Furthermore, in the step 4, the annealing equipment used during the annealing treatment is one or more of a muffle furnace, a tubular furnace, and a Joule heat reactor.

[0021] Furthermore, in step 4, the annealing temperature is 200° C. to 600° C., the annealing time is 0.5 h to 3 h, and the high temperature annealing environment is one of air, oxygen, ozone, nitrogen, argon and oxygen-argon.

[0022] Furthermore, in step five, the detergent is selected from one or more of deionized water, anhydrous ethanol, isopropanol, n-propanol, methanol, acetone, ammonium hydroxide, sodium hydroxide, nitric acid, and sulfuric acid.

[0023] Beneficial effects of the present invention:

[0024] 1. The preparation method of the present invention uses zirconium dioxide as a carrier to form a PEM water electrolysis hydrogen production catalyst with a lower iridium content, and controls the agglomeration of iridium oxide during the annealing process by dispersing and mixing, so that it is evenly loaded on the zirconium oxide carrier. At the same time, zirconium oxide is selected as a carrier to effectively improve the mechanical properties of the catalyst and the degree of easy dispersion when preparing the slurry. The tolerance and service life of the catalyst are more effectively improved;

[0025] 2. The preparation method of the present invention has a simple process principle, without complicated operations and expensive consumables. The advantages also include that the amount of iridium used can be greatly reduced, small active particles can be stabilized to prevent sintering and catalytic activity can be increased.

[0026] 3. The preparation method of the present invention can significantly reduce the crystallite particles of the catalyst, increase the specific surface area of ​​the catalyst, and enhance the activity of the catalyst by adjusting the temperature and time of the annealing process;

[0027] 4. The anode catalyst prepared by the preparation method of the present invention has better catalytic effect. When the catalyst of the present invention is used as the anode of the acidic water electrolysis device at the same current density, the use effect is better than that of the iridium oxide catalyst prepared by other processes. The production unit volume of oxygen has lower specific energy consumption and has a basic electrolysis voltage at the same current density, while the iridium oxide catalyst of other processes has a lower specific energy consumption at 10mA / cm 2 The overpotential under the condition is 300mV~350mV; and when the supported iridium oxide catalyst prepared by the present invention is used as the anode catalyst for water electrolysis, 10mA / cm 2 The electrolysis voltage was 280 mV at 2 A / cm 2 The cell voltage is 1.81V. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below in conjunction with the accompanying drawings.

[0029] Figure 1 is a preparation flow chart of the zirconium-supported iridium oxide catalyst of the present invention;

[0030] Figure 2 is a transmission electron microscope scanning image of Example 1 of the present invention;

[0031] Figure 3 It is a linear voltammetric curve scanning diagram of Example 1, Example 2 and Example 3 of the present invention under 0.5M sulfuric acid;

[0032] Figure 4 It is a polarization curve diagram of PEM hydrogen production in Example 1 of the present invention.

[0033] Figure 5This is a durability diagram of Example 1 of the present invention when a small electrolytic cell stack is assembled. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] A method for preparing a zirconium-supported iridium oxide-type PEMWE anode catalyst, such as Figure 1 , Figure 5 As shown, the preparation method comprises the following steps:

[0036] Step 1: Dispersion:

[0037] Zirconium dioxide as a carrier powder to be loaded is put into an iridium dispersion and uniformly dispersed in the dispersion to obtain a carrier solvent mixed solution.

[0038] Step 2: Evaporation:

[0039] The mixed dispersion is dried evenly to make the iridium precursor evenly distributed on the surface of the carrier;

[0040] The evaporation method is selected from one or more of low-temperature drying, vacuum drying, freeze drying and rotary evaporation.

[0041] Step 3: Mixing:

[0042] adding molten salt to the mixture and uniformly mixing the molten salt with the loaded precursor;

[0043] The mixing method of the precursor molten salt is selected from one or more of ball milling, stirring, rotary evaporation and grinding.

[0044] Step 4: Annealing:

[0045] calcining and crystallizing the mixed reactants at high temperature to form a final product;

[0046] The annealing equipment used during the annealing treatment is one or more of a muffle furnace, a tubular furnace, and a Joule heat reactor;

[0047] The annealing temperature is 200° C. to 600° C., the annealing time is 0.5 h to 3 h, and the high temperature annealing environment is one of air, oxygen, ozone, nitrogen, argon and oxygen-argon.

[0048] Step 5: Washing:

[0049] The calcined and annealed powder is redissolved, washed with a large amount of detergent, and dried after washing to obtain a zirconium-supported iridium oxide catalyst;

[0050] The detergent is selected from one or more of deionized water, anhydrous ethanol, isopropanol, n-propanol, methanol, acetone, ammonium hydroxide, sodium hydroxide, nitric acid, and sulfuric acid.

[0051] The raw material ratios of the components for preparing the zirconium-supported iridium oxide-type PEMWE anode catalyst are as follows:

[0052] 1 part to 2.8 parts of zirconium dioxide, 1.25 parts to 8 parts of iridium-containing solution, 500 parts to 1000 parts of dispersant, 40 parts to 80 parts of fusion salt, and 2000 parts to 4000 parts of detergent.

[0053] The dispersant is selected from one or more of deionized water, ethanol, n-propanol, isopropanol, ethylene glycol, methanol and acetone.

[0054] The solute used in the iridium-containing solution is selected from one or more of chloroiridic acid, potassium chloroiridate, iridium chloride, iridium acetate, iridium acetylacetonate, iridium chloride, sodium chloroiridate, and ammonium chloroiridate.

[0055] The molten salt is selected from one or more of sodium nitrate, sodium acetate, sodium citrate, sodium formate, sodium chloride, sodium nitrite, sodium carbonate, ammonium nitrate, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, polyvinyl pyrrolidone, and polyethylene glycol.

[0056] Example 1

[0057] Dispersing 1 part of zirconium dioxide uniformly in 500 parts of deionized water to obtain a carrier solvent mixture;

[0058] Then, 1.25 parts of chloroiridic acid was slowly added into the obtained carrier solvent mixture, and the mixture was rapidly stirred for 30 minutes.

[0059] Then transfer it to a rotary evaporation bottle and evaporate it under reduced pressure for 2 hours to make it completely dry.

[0060] After it is completely dried, the precursor is transferred to a ball mill, and 40 parts of sodium nitrate are added thereto, and ball milling is performed for 2 hours to uniformly mix the precursor with the precursor.

[0061] Afterwards, the mixture was spread evenly in a crucible and calcined at 375° C. for 1 h to convert the precursor into a zirconium-supported iridium oxide powder product.

[0062] After the reaction is completed, the reactor is taken out, washed by centrifugation with deionized water and ethanol for multiple times, and dried under vacuum at 60° C. to obtain the final product (i.e., zirconium-supported iridium oxide catalyst).

[0063] In the electrochemical test, the obtained iridium oxide is evenly distributed on the surface of zirconium dioxide, the iridium content is about 40%, and the content of other impurities is less than 0.01%. 2 The lower overpotential is 251mV at 2A / cm -2 The voltage of PEM water electrolysis to produce hydrogen is 1.824V.

[0064] Example 2

[0065] Dispersing 1.5 parts of zirconium dioxide uniformly in 750 parts of deionized water to obtain a carrier solvent mixture;

[0066] Then, 2 parts of chloroiridic acid were slowly added into the obtained carrier solvent mixture and stirred rapidly for 30 minutes.

[0067] Then transfer it to a rotary evaporation bottle and evaporate it under reduced pressure for 2 hours to make it completely dry.

[0068] After it is completely dried, the precursor is transferred to a ball mill, and 60 parts of sodium nitrate are added thereto, and ball milling is performed for 2 hours to uniformly mix the precursor with the precursor.

[0069] Afterwards, the mixture was spread evenly in a crucible and calcined at 500 degrees for 1 hour to convert the precursor into a zirconium-supported iridium oxide powder product.

[0070] After the reaction is completed, the reactor is taken out, washed by centrifugation with deionized water and ethanol for multiple times, and dried under vacuum at 60° C. to obtain the final product (i.e., zirconium-supported iridium oxide catalyst).

[0071] In the electrochemical test, the obtained iridium oxide is evenly distributed on the surface of zirconium dioxide, the iridium content is about 40%, and the content of other impurities is less than 0.01%. 2 The lower overpotential is 250mV at 2A / cm -2 The voltage of PEM water electrolysis to produce hydrogen is 1.818V.

[0072] Example 3

[0073] 2.8 parts of zirconium dioxide are uniformly dispersed in 1000 parts of deionized water to obtain a carrier solvent mixed solution;

[0074] Then, 8 parts of chloroiridic acid were slowly added to the obtained carrier solvent mixture, and 30 parts were quickly stirred.

[0075] Then transfer it to a rotary evaporation bottle and evaporate it under reduced pressure for 2 hours to make it completely dry.

[0076] After it is completely dried, the precursor is transferred to a ball mill, and 80 parts of sodium nitrate are added thereto, and ball milling is performed for 2 hours to uniformly mix the precursor with the precursor.

[0077] Afterwards, the mixture was spread evenly in a crucible and calcined at 600 degrees for 1 hour to convert the precursor into a zirconium-supported iridium oxide powder product.

[0078] After the reaction is completed, the reactor is taken out, washed by centrifugation with deionized water and ethanol for multiple times, and dried under vacuum at 60° C. to obtain the final product (i.e., zirconium-supported iridium oxide catalyst).

[0079] In the electrochemical test, the obtained iridium oxide is evenly distributed on the surface of zirconium dioxide, the iridium content is about 50%, and the content of other impurities is less than 0.01%. 2 The lower overpotential is 254mV at 2A / cm -2 The voltage of PEM water electrolysis to produce hydrogen is 1.820V.

[0080] In this embodiment, zirconium dioxide is used as a carrier to form a PEM water electrolysis hydrogen production catalyst with a low iridium content, and the agglomeration of iridium oxide during the annealing process is controlled and solved by a dispersed mixing method, so that it is evenly loaded on the zirconium oxide carrier. At the same time, zirconium oxide is selected as a carrier to effectively improve the mechanical properties of the catalyst and the degree of dispersion when preparing the slurry. More effectively improve the tolerance and service life of the catalyst; the preparation process principle is simple, without complex operations and expensive consumables; by adjusting the temperature and time of the annealing process, the microcrystalline particles of the catalyst can be significantly reduced, the specific surface area of ​​the catalyst can be increased, and the activity of the catalyst can be enhanced; the prepared anode catalyst has a better catalytic effect. When the catalyst of the present invention is used for the anode of the acidic water electrolysis device at the same current density, the use effect is due to the iridium oxide catalyst prepared by other processes. The production unit volume of oxygen has a lower specific energy consumption and a basic electrolysis voltage at the same current density, while the iridium oxide catalyst of other processes is at 10mA / cm 2 The overpotential under the condition is 300mV~350mV; and when the supported iridium oxide catalyst prepared by the present invention is used as the anode catalyst for water electrolysis, 10mA / cm 2 The electrolysis voltage was 280 mV at 2 A / cm 2 The cell voltage is 1.81V.

[0081] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for preparing a zirconium-supported iridium oxide-type PEMWE anode catalyst, characterized in that: The following steps are involved: Step 1, dispersion: adding zirconium dioxide as a carrier powder to be loaded into an iridium dispersion and uniformly dispersing it in the dispersion to obtain a carrier solvent mixed solution; Step 2, evaporation: drying the mixed dispersion evenly to make the iridium precursor evenly distributed on the surface of the carrier; Step 3, mixing: adding molten salt to the mixture and uniformly mixing the molten salt and the loaded precursor; Step 4: Annealing: calcining the mixed reactants at high temperature to crystallize the final product; Step 5, washing: re-dissolving the calcined and annealed powder, washing it with a detergent, and drying it after washing to obtain a zirconium-supported iridium oxide catalyst.

2. The method for preparing a zirconium-supported iridium oxide-type PEMWE anode catalyst according to claim 1, characterized in that: The raw material ratios of the components for preparing the zirconium-supported iridium oxide-type PEMWE anode catalyst are as follows: 1 part to 2.8 parts of zirconium dioxide, 1.25 parts to 8 parts of iridium-containing solution, 500 parts to 1000 parts of dispersant, 40 parts to 80 parts of fusion salt, and 2000 parts to 4000 parts of detergent.

3. The method for preparing a zirconium-supported iridium oxide-type PEMWE anode catalyst according to claim 1, characterized in that: In the step 1, the dispersant is selected from one or more of deionized water, ethanol, n-propanol, isopropanol, ethylene glycol, methanol, and acetone.

4. The method for preparing a zirconium-supported iridium oxide-type PEMWE anode catalyst according to claim 1, characterized in that: In the step 1, the solute used in the iridium-containing solution is selected from one or more of chloroiridic acid, potassium chloroiridate, iridium chloride, iridium acetate, iridium acetylacetonate, iridium chloride, sodium chloroiridate, and ammonium chloroiridate.

5. The method for preparing a zirconium-supported iridium oxide-type PEMWE anode catalyst according to claim 1, characterized in that: In the step 2, the evaporation method is selected from one or more of low-temperature drying, vacuum drying, freeze drying, and rotary evaporation.

6. The method for preparing a zirconium-supported iridium oxide-type PEMWE anode catalyst according to claim 1, characterized in that: In the step three, the molten salt is selected from one or more of sodium nitrate, sodium acetate, sodium citrate, sodium formate, sodium chloride, sodium nitrite, sodium carbonate, ammonium nitrate, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, polyvinyl pyrrolidone, and polyethylene glycol.

7. The method for preparing a zirconium-supported iridium oxide-type PEMWE anode catalyst according to claim 1, characterized in that: In the step three, the mixing method of the precursor molten salt is selected from one or more of ball milling, stirring, rotary evaporation and grinding.

8. The method for preparing a zirconium-supported iridium oxide-type PEMWE anode catalyst according to claim 1, characterized in that: In the step 4, the annealing equipment used during the annealing treatment is one or more of a muffle furnace, a tubular furnace, and a Joule heat reactor.

9. The method for preparing a zirconium-supported iridium oxide-type PEMWE anode catalyst according to claim 8, characterized in that: In the step 4, the annealing temperature is 200° C. to 600° C., the annealing time is 0.5 h to 3 h, and the high temperature annealing environment is one of air, oxygen, ozone, nitrogen, argon and oxygen-argon.

10. The method for preparing a zirconium-supported iridium oxide-type PEMWE anode catalyst according to claim 1, characterized in that: In the step 5, the detergent is selected from one or more of deionized water, anhydrous ethanol, isopropanol, n-propanol, methanol, acetone, ammonium hydroxide, sodium hydroxide, nitric acid, and sulfuric acid.

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