A type of Ir 0.82 Sn 0.18 O2 porous nanosheets, their preparation methods and applications

Abstract

This invention discloses an Ir 0.82 Sn 0.18 O2 porous nanosheets, their preparation method and application, the method comprising the following steps: (1) dissolving iridium chloride, hydrated tin chloride, sodium nitrate and hydrated citric acid in a mixed solvent of ethanol and deionized water, stirring evenly to obtain a precursor mixed solution; (2) centrifuging the precursor mixed solution, collecting the precipitate and drying it to obtain precursor powder; (3) calcining the precursor powder in an air atmosphere, and naturally cooling it to obtain the calcined product; (4) washing the calcined product alternately with deionized water and ethanol, and drying it to obtain Ir 0.82 Sn 0.18 O2 porous nanosheets. This invention is simple to operate and has good reproducibility. By doping with Sn, the loading of the noble metal Ir is reduced, while the synergistic effect between Ir and Sn is utilized to effectively improve the catalytic activity and operational stability of the material.

Description

Technical Field

[0001] This invention relates to the field of acidic water electrolysis technology, specifically to an Ir 0.82 Sn 0.18 O2 porous nanosheets, their preparation methods, and applications. Background Technology

[0002] To alleviate the environmental pressure from fossil fuels, developing new energy infrastructure based on renewable energy is imperative, with building a sustainable hydrogen economy being a key direction. Proton exchange membrane electrolysis (PEMWE) has attracted significant attention due to its rapid response, ability to directly produce high-pressure hydrogen, and good compatibility with the highly volatile renewable energy sources. However, the large-scale application of PEMWE technology is still limited by the performance of its oxygen evolution reaction (OER) catalyst. IrO2 has relatively good stability and has therefore become the mainstream anode material for PEMWE. However, the scarcity and high price of the precious metal Ir increases the cost of hydrogen production through water electrolysis. Therefore, developing efficient, stable, and low-cost acidic OER catalysts is crucial for promoting the widespread application of PEMWE technology.

[0003] In summary, a simple and efficient preparation method is needed to synthesize highly efficient and stable Ir-based electrocatalysts, ensuring that the material possesses high activity and good stability to meet its application as an Ir-based catalyst material in water electrolysis. Summary of the Invention

[0004] The purpose of this invention is to provide an Ir 0.82 Sn 0.18 O2 porous nanosheets, their preparation methods, and applications: By introducing Sn elements to form a composite oxide structure, the catalytic performance is optimized and the operational stability is improved by utilizing the synergistic effect between Ir and Sn while reducing the Ir loading. This provides a new strategy for efficient, stable, and low-cost PEMWE anode catalysts.

[0005] In one aspect of the invention, an Ir is proposed. 0.82 Sn 0.18 A method for preparing O2 porous nanosheets. According to an embodiment of the present invention, the method includes the following steps:

[0006] (1) Dissolve iridium chloride, hydrated tin chloride, sodium nitrate and hydrated citric acid in a mixed solvent of ethanol and deionized water, stir evenly to obtain a precursor mixed solution;

[0007] (2) Centrifuge the precursor mixture solution, collect the precipitate and dry it to obtain precursor powder;

[0008] (3) The precursor powder was calcined in air atmosphere and then naturally cooled to obtain the calcined product;

[0009] (4) The calcined product was washed alternately with deionized water and ethanol, and dried to obtain Ir. 0.82 Sn 0.18 O2 porous nanosheets.

[0010] In addition, according to the above embodiments of the present invention, an Ir 0.82 Sn 0.18 The preparation method of O2 porous nanosheets can also have the following additional technical features:

[0011] In some embodiments of the present invention, in step (1), the mass ratio of iridium chloride, hydrated tin chloride, sodium nitrate, and hydrated citric acid is (30~50):(40~60):(1800~2200):(50~70), and the volume ratio of ethanol to deionized water is (8~12):(28~32). Iridium chloride is used as an iridium source, hydrated tin chloride is used as a tin source, sodium nitrate provides a sheet template, and citric acid is used as a crosslinking agent.

[0012] In some embodiments of the present invention, the stirring time in step (1) is 0.5 to 1.5 h. Thorough stirring can ensure that the raw materials are evenly dispersed, which is beneficial for subsequent calcination to generate uniformly dispersed Ir and Sn oxide nanosheets.

[0013] In some embodiments of the present invention, in step (2), the centrifugation speed is 8000~12000 rpm, and the centrifugation time is 5~10 min; the drying temperature is 60~80 ℃, and the drying time is 10~14 h. Thorough centrifugation is performed to collect the pretreated sample and reduce losses. The sample is then dried in an oven at a suitable temperature for subsequent calcination.

[0014] In some embodiments of the present invention, in step (3), the heating rate of the calcination treatment is 3~8 ℃ / min, the calcination temperature is 350~450 ℃, and the holding time is 80~120 min. Sufficient calcination forms iridium-tin oxide nanosheets. If the temperature is too low, the sample will not be completely oxidized; if the temperature is too high, the sample is prone to agglomeration, which is not conducive to maintaining the morphology.

[0015] In some embodiments of the present invention, in step (4), the total number of washing cycles is 5 to 7; the drying temperature is 60 to 80 °C, and the drying time is 4 to 6 h. The mixture is washed several times with water and ethanol to remove residual impurities and unreacted substances, and then dried and stored.

[0016] In another aspect of the invention, the invention proposes a method for providing the aforementioned Ir 0.82 Sn 0.18Ir prepared by O2 porous nanosheets 0.82 Sn 0.18 O2 porous nanosheets were formed using iridium chloride as the iridium source, hydrated tin chloride as the tin source, sodium nitrate as the sheet template, and water and citric acid to stabilize the morphology. After homogeneous mixing, the mixture was calcined in air to form iridium-tin oxide nanosheets. Simultaneously, nitrate ions reacted at high temperature to generate NO2, which detached and formed pores on the sheets. Finally, washing removed sodium and unreacted substances to obtain Ir. 0.82 Sn 0.18 O2 porous nanosheets.

[0017] In another aspect of the invention, the invention proposes a method for providing the aforementioned Ir 0.82 Sn 0.18 Applications of O2 porous nanosheets. According to embodiments of the present invention, the Ir... 0.82 Sn 0.18 O2 porous nanosheets were used to prepare anode catalysts for proton exchange membrane water electrolysis. Ir 0.82 Sn 0.18 O2 porous nanosheets, through the strong electronic synergy between Ir and Sn, significantly enhance the catalyst's corrosion resistance while ensuring high catalytic activity. Furthermore, their unique porous nanosheet structure increases the number of active sites and optimizes the transport efficiency of reactants and protons. Therefore, it becomes a high-quality anode catalyst for proton exchange membrane water electrolysis that can reduce the amount of precious metal iridium used, achieving high performance and long lifespan.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. This invention successfully constructs porous IrSn composite oxide nanosheets through a simple liquid-phase mixing and high-temperature calcination process. This method is simple to operate, low in cost, easily reproducible, and yields a stable product structure.

[0020] 2. This invention introduces the non-noble metal Sn to IrO x By doping, the surface electronic structure of the catalyst was modulated by utilizing the electronic synergistic effect between Ir and Sn, while significantly reducing the loading of the noble metal Ir. The strong electronic interaction between Ir and Sn can greatly reduce the d-band holes in the Ir species. The fewer the d-band holes, the lower the oxidation state of Ir. The lower oxidation state makes Ir less likely to be oxidized to a higher oxidation state and dissolve, even at the high anodic potential (>1.6 V) of PEMWE, thus significantly improving the corrosion resistance of the catalyst. The synergistic effect between Ir and Sn can also optimize the adsorption energy of OER reaction intermediates on the catalyst surface. This helps the catalyst to drive the reaction with a lower energy barrier, intrinsically improving the catalytic activity. Therefore, Sn is beneficial to IrO. xDoping can effectively enhance the intrinsic catalytic activity and stability of materials, while reducing the loading of noble metals.

[0021] 3. The product obtained by this invention has a unique porous nanosheet structure. Its large specific surface area is conducive to exposing more active sites. At the same time, the porous structure provides an efficient channel for rapid mass transfer, thereby significantly improving its performance in PEMWE anodes and providing a new strategy for achieving efficient, stable and low-cost water electrolysis hydrogen production technology. Attached Figure Description

[0022] Figure 1 The Ir obtained in Embodiment 1 of the present invention 0.82 Sn 0.18 Transmission electron microscopy (TEM) images and high-resolution transmission electron microscopy (HRTEM) images of O2 porous nanosheets are shown. Image a is a TEM image, image b is a HRTEM image, and image c is an energy dispersive spectroscopy (EDS) elemental mapping image. From left to right, the images are: high-angle annular dark field image of the sample, EDS surface distribution map of Ir element, EDS surface distribution map of Sn element, and EDS surface distribution map of O element.

[0023] Figure 2 These are TEM images of IrSn composite oxide nanosheets with different ratios obtained in Comparative Examples 1, 2, and 3 of this invention, where image a is Comparative Example 1 (Ir 0.93 Sn 0.07 TEM images of the O2 composite material, and Figure b is a comparative example 2 (Ir). 0.73 Sn 0.27 TEM images of the O2 composite material, and image c is comparative example 3 (Ir). 0.58 Sn 0.42 TEM image of the O2 composite material;

[0024] Figure 3 The Ir obtained in Embodiment 1 of the present invention 0.82 Sn 0.18 X-ray diffraction (XRD) pattern of O2 porous nanosheets. In the figure, IrO2-PDF#15-1870 represents the iridium dioxide standard PDF (powder diffraction card database) card, number 15-1870, and SnO2-PDF#41-1445 represents the tin dioxide standard PDF card, number 41-1445.

[0025] Figure 4 This is a comparison chart of the electrochemical performance of IrSn composite oxide nanosheets with different proportions obtained in Example 1 and Comparative Examples 1-3 of the present invention and commercial IrO2.

[0026] Figure 5 In Example 1 of the present invention, the Ir obtained in Example 1 is used. 0.82 Sn 0.18PEMWE activity test results of O2 porous nanosheets and commercial IrO2;

[0027] Figure 6 In Example 1 of the present invention, the Ir obtained in Example 1 is used. 0.82 Sn 0.18 PEMWE stability test results of O2 porous nanosheets. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] The electric thermostatic drying oven (DHG) used in the following examples and comparative examples was a DHG-9011A oven manufactured by Shanghai Jinghong; the transmission electron microscope was a JEOL (Japan Electronics Corporation) F2010 manufactured in Japan; and the centrifuge was a (Anting) TGL (tabletop high-speed refrigerated centrifuge)-10B manufactured by Shanghai Anting Scientific Instrument Factory, PEMWE Automatic Measurement Green Energy Co., Ltd. The chemicals used in the following examples were used directly without any treatment after purchase.

[0030] Example 1

[0031] A type of Ir 0.82 Sn 0.18 The method for preparing O2 porous nanosheets includes the following steps:

[0032] Step 1: Take a clean 100 mL beaker and add 40 mg of IrCl3, 47 mg of SnCl4·5H2O, 2 g of NaNO3, and 60 mg of C6H8O7·H2O in sequence. Then add 10 mL of ethanol and 30 mL of deionized water to the beaker as a mixed solvent. Place the mixture on a magnetic stirrer and stir at room temperature for 1 h to ensure that all solids are fully dissolved and mixed evenly, thus obtaining the precursor solution.

[0033] Step 2: Transfer the precursor solution obtained in Step 1 to a 50 mL centrifuge tube and centrifuge at 10,000 rpm for 7 min, collecting the precipitate. Place the precipitate in a vacuum drying oven and dry at 80 °C for 12 h to obtain the precursor powder.

[0034] Step 3: Place the precursor powder obtained in Step 2 into a high-temperature tube furnace and heat it to 400 °C at a heating rate of 5 °C / min in air atmosphere, and hold it at this temperature for 100 min. After the furnace body cools naturally to room temperature, remove the calcined product.

[0035] Step 4: Wash the calcined product obtained in Step 3 six times with deionized water and ethanol to remove unreacted impurities and residual solvent. Finally, dry the washed product in a vacuum drying oven at 60 °C for 4 h to obtain Ir. 0.82 Sn 0.18 O2 porous nanosheets.

[0036] Depend on Figure 1 As shown in Figure a, Ir can be seen 0.82 Sn 0.18 O2 porous nanosheets have a microporous structure, as shown in Figure b. 0.82 Sn 0.18 The lattice spacing of the O2 porous nanosheets is between that of IrO2 and SnO2. Figure c shows the IrO2... 0.82 Sn 0.18 EDS mapping analysis of the O2 porous nanosheet catalyst revealed that Ir and Sn were uniformly distributed on the nanosheets. EDS analysis confirmed that the IrSn composite porous nanosheet component was composed primarily of Ir. 0.82 Sn 0.18 O2.

[0037] Depend on Figure 3 As shown, Ir 0.82 Sn 0.18 The XRD peaks of the O2 porous nanosheets are between IrO2 and SnO2.

[0038] Example 2

[0039] A type of Ir 0.82 Sn 0.18 The preparation method of O2 porous nanosheets differs from that of Example 1 only in that: in step 3, the calcination temperature is raised to 300 °C, while the other steps and parameters are the same as in Example 1.

[0040] Example 3

[0041] A type of Ir 0.82 Sn 0.18 The preparation method of O2 porous nanosheets differs from that of Example 1 only in that: in step 3, the calcination temperature is raised to 500 °C, while the other steps and parameters are the same as in Example 1.

[0042] Comparative Example 1

[0043] A type of Ir 0.93 Sn 0.07The preparation method of the O2 composite material differs from Example 1 only in that: in step 1, the mass of IrCl3 is 40 mg and the mass of SnCl4·5H2O is 23 mg; all other steps and parameters are the same as in Example 1. This embodiment ultimately yields IrCl3. 0.93 Sn 0.07 O2 composite material.

[0044] Comparative Example 2

[0045] A type of Ir 0.73 Sn 0.27 The preparation method of the O2 composite material differs from Example 1 only in that: in step 1, the mass of IrCl3 is 40 mg and the mass of SnCl4·5H2O is 93 mg; all other steps and parameters are the same as in Example 1. This embodiment ultimately yields Ir... 0.73 Sn 0.27 O2 composite material.

[0046] Comparative Example 3

[0047] A type of Ir 0.58 Sn 0.42 The preparation method of the O2 composite material differs from Example 1 only in that: in step 1, the mass of IrCl3 is 40 mg and the mass of SnCl4·5H2O is 140 mg; all other steps and parameters are the same as in Example 1. This embodiment ultimately yields Ir... 0.58 Sn 0.42 O2 composite material.

[0048] like Figure 2 As shown, Ir 0.93 Sn 0.07 O2 composite materials, Ir 0.73 Sn 0.27 O2 composite materials, Ir 0.58 Sn 0.42 All O2 composite materials have a sheet-like structure.

[0049] Weigh out 2 mg of Ir 0.82 Sn 0.18 O2 porous nanosheets, Ir 0.93 Sn 0.07 O2 composite materials, Ir 0.73 Sn 0.27 O2 composite materials, Ir 0.58 Sn 0.42O2 composite material and commercial IrO2 were mixed with 390 μL ethanol and 10 μL Nafion, and sonicated for at least 30 min to form a uniform dispersion of the catalyst. Subsequently, 25 μL of the dispersion was drop-coated onto the surface of a glassy carbon electrode. After the solvent dried, the resulting modified electrode was used as the working electrode for OER performance testing. A three-electrode system was used, with an Ag / AgCl electrode as the reference electrode and a graphite carbon electrode as the counter electrode, in an O2-saturated atmosphere at 0.5 mol / L... -1 Electrochemical tests were conducted in H2SO4 electrolyte.

[0050] like Figure 4 As shown, the Ir prepared by this invention 0.82 Sn 0.18 The activity of O2 porous nanosheets is significantly higher than that of Ir. 0.93 Sn 0.07 O2 composite materials, Ir 0.73 Sn 0.27 O2 composite materials, Ir 0.58 Sn 0.42 O2 composite materials and commercial IrO2. At a current density of 10 mA cm⁻¹. -2 At that time, its overpotential is 294 mV.

[0051] Application Example 1

[0052] The Ir prepared in Example 1 0.82 Sn 0.18 O2 porous nanosheets were used as an anode catalyst in PEMWE devices, and the specific testing method is as follows:

[0053] The Ir prepared in Example 1 0.82 Sn 0.18 O2 porous nanosheet catalyst was sprayed onto the anode side of a proton exchange membrane (PEM) as the anode material, wherein the Ir noble metal loading was controlled at 0.35 mg / cm³. −2 The cathode was coated with 60% commercially available Pt / C catalyst on the PEM cathode side, with a Pt loading of 0.4 mg / cm³. −2 The PEM used was a Nafion (perfluorosulfonic acid proton exchange membrane) 115 membrane. The membrane with double-sided catalyst coating, the anode porous transport layer (PTL, 0.23 mm thick platinum-titanium fiber felt), the cathode gas diffusion layer (Toray carbon paper TGP-H-060), the PTFE gasket, and the bipolar plate were assembled into a membrane electrode assembly (MEA). The assembled MEA assembly was subjected to PEMWE performance testing. Before testing, the temperature was 0.4 A cm⁻¹. -2 Activation was completed after running at the current density for 1 hour.

[0054] like Figure 5 As shown, the Ir prepared in Example 10.82 Sn 0.18 O2 porous nanosheets at 1 A cm -2 At the current density, the voltage is only 1.64 V, which is significantly lower than that of commercial IrO2 catalysts.

[0055] like Figure 6 As shown, the Ir prepared in Example 1 0.82 Sn 0.18 O2 porous nanosheets at 1 A cm -2 It exhibits excellent stability at current densities.

[0056] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A type of Ir 0.82 Sn 0.18 The method for preparing O2 porous nanosheets is characterized by, Includes the following steps: (1) Dissolve iridium chloride, hydrated tin chloride, sodium nitrate and hydrated citric acid in a mixed solvent of ethanol and deionized water, stir evenly to obtain a precursor mixed solution; (2) Centrifuge the precursor mixture solution, collect the precipitate and dry it to obtain precursor powder; (3) The precursor powder was calcined in air atmosphere and then naturally cooled to obtain the calcined product; (4) The calcined product was washed alternately with deionized water and ethanol, and dried to obtain Ir. 0.82 Sn 0.18 O2 porous nanosheets.

2. An Ir according to claim 1 0.82 Sn 0.18 The method for preparing O2 porous nanosheets is characterized by: In step (1), the mass ratio of iridium chloride, hydrated tin chloride, sodium nitrate, and hydrated citric acid is (30~50):(40~60):(1800~2200):(50~70), and the volume ratio of ethanol to deionized water is (8~12):(28~32).

3. An Ir according to claim 1 0.82 Sn 0.18 The method for preparing O2 porous nanosheets is characterized by: In step (1), the stirring time is 0.5~1.5 h.

4. An Ir according to claim 1 0.82 Sn 0.18 The method for preparing O2 porous nanosheets is characterized by: In step (2), the centrifugation speed is 8000~12000 rpm and the centrifugation time is 5~10 min; the drying temperature is 60~80 ℃ and the drying time is 10~14 h.

5. An Ir according to claim 1 0.82 Sn 0.18 The method for preparing O2 porous nanosheets is characterized by: In step (3), the heating rate of the calcination treatment is 3~8 ℃ / min, the calcination temperature is 350~450 ℃, and the holding time is 80~120 min.

6. An Ir according to claim 1 0.82 Sn 0.18 The method for preparing O2 porous nanosheets is characterized by: In step (4), the total number of washing cycles is 5 to 7; the drying temperature is 60 to 80 ℃, and the drying time is 4 to 6 h.

7. An Ir according to any one of claims 1-6 0.82 Sn 0.18 Ir prepared by O2 porous nanosheets 0.82 Sn 0.18 O2 porous nanosheets.

8. The Ir as described in claim 7 0.82 Sn 0.18 The application of O2 porous nanosheets is characterized by: The Ir 0.82 Sn 0.18 O2 porous nanosheets were used to prepare an anode catalyst for proton exchange membrane water electrolysis.

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