Mica-metal oxide composite nanomaterial, and preparation method and application thereof

Abstract

The application relates to the technical field of hydrogen production by electrolysis of water, in particular to a mica-metal oxide composite nanomaterial and a preparation method and application thereof. The composite nanomaterial takes mica powder as a carrier and is loaded with nickel oxide nanoparticles. The mica powder is used as the carrier of the nickel oxide nanoparticles, which can not only solve the problem of reduced catalytic effect of the nickel oxide nanoparticles due to agglomeration, but also can improve the overall catalytic life of the composite nanomaterial due to good wear resistance.

Description

Technical Field

[0001] This invention relates to the field of water electrolysis for hydrogen production, specifically to a mica-metal oxide composite nanomaterial, its preparation method, and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Hydrogen, with its high energy density and zero carbon emissions, is widely recognized as a crucial carrier for driving sustainable energy transformation and is considered one of the most promising clean energy sources of the 21st century. Electrolysis of water to produce hydrogen has become a key technology in the hydrogen production field due to its ease of operation and pure products. However, the slow kinetics and large overpotentials in the electrochemical oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) significantly hinder the achievement of high energy efficiency and power output in various related applications. Therefore, ideal electrocatalysts with high activity, high stability, and low cost are extremely important for accelerating the redox kinetics of electrochemical processes.

[0004] To date, noble metal catalysts, such as Pt-based, Ru-based, and Ir-based catalysts, remain commercially available catalysts for the electrochemical oxygen reduction reaction, oxygen evolution reaction, and hydrogen evolution reaction. However, noble metal catalysts are not only expensive and lack long-term durability, but their catalytic activity is also limited, restricting their further development.

[0005] In recent years, transition metals and their compounds have been considered as potential substitutes for precious metals due to their abundant reserves, tunable catalytic performance, and low price. However, the catalytic activity, stability, and multifunctionality of unregulated transition metals and their compounds cannot meet the application requirements. Summary of the Invention

[0006] To overcome the above problems, this invention provides a mica-metal oxide composite nanomaterial, its preparation method, and its application.

[0007] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a mica-metal oxide composite nanomaterial, wherein mica powder is used as a carrier and nickel oxide nanoparticles are loaded thereon.

[0009] The particle size of the mica powder is 5~8 μm.

[0010] Nickel oxide nanoparticles are nanosheets with a particle size of 1~2 μm.

[0011] A second aspect of the present invention provides a method for preparing the mica-metal oxide composite nanomaterial described in the first aspect, comprising the following steps:

[0012] (1) Mica powder and nickel powder were ball-milled to obtain a precursor;

[0013] (2) The precursor is calcined in an oxygen atmosphere to obtain the mica-metal oxide composite nanomaterial.

[0014] A third aspect of the present invention provides the application of the mica-metal oxide composite nanomaterial described in the first aspect as a catalyst.

[0015] A fourth aspect of the present invention provides a catalyst layer slurry for hydrogen production by water electrolysis, comprising a binder, a conductive material, and the mica-metal oxide composite nanomaterial described in the first aspect.

[0016] The beneficial effects of this invention are as follows:

[0017] (1) This invention provides a mica-metal oxide composite nanomaterial, its preparation method, and its application. The composite nanomaterial uses mica powder as a carrier and loads nickel oxide nanoparticles. Using mica powder as a carrier for nickel oxide nanoparticles can not only solve the problem of reduced catalytic effect due to agglomeration of nickel oxide nanoparticles, but also improve the overall catalytic life of the composite nanomaterial due to its good wear resistance.

[0018] (2) In this invention, mica powder is used as a carrier for nickel oxide nanoparticles, which can improve the catalytic effect while reducing the amount of transition metal nickel.

[0019] (3) The mica-metal oxide composite nanomaterials provided by the present invention have a simple preparation method, low cost, and are easy to industrialize. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0021] Figure 1 Scanning electron microscope images of the mica-metal oxide composite nanomaterial NiO / Mica at different magnifications (a~d).

[0022] Figure 2 XRD images of mica powder, precursor Ni / Mica, and mica-metal oxide composite nanomaterial NiO / Mica;

[0023] Figure 3EDX image of the mica-metal oxide composite nanomaterial NiO / Mica;

[0024] Figure 4 OER polarization curves of nickel-iron foam substrate, mica powder, precursor Ni / Mica, mica-metal oxide composite nanomaterials NiO / Mica and RuO2;

[0025] Figure 5 Tafel slopes of OER polarization curves for foamed nickel-iron substrate, mica powder, precursor Ni / Mica, mica-metal oxide composite nanomaterials NiO / Mica, and RuO2.

[0026] Figure 6 Electrochemical impedance spectroscopy results for nickel-iron foam substrate, mica powder, precursor Ni / Mica, mica-metal oxide composite nanomaterials NiO / Mica, and RuO2;

[0027] Figure 7 The results show the stability test results of the mica-metal oxide composite nanomaterial NiO / Mica.

[0028] Figure 8 Polarization curves of working electrodes and substrates prepared for NiO / Mica composite nanomaterials with different Ni contents. Detailed Implementation

[0029] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0030] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] The first typical embodiment of the present invention provides a mica-metal oxide composite nanomaterial, which uses mica powder as a carrier and loads nickel oxide nanoparticles.

[0032] The particle size of the mica powder is 5~8 μm.

[0033] Nickel oxide nanoparticles are nanosheets with a particle size of 1~2 μm.

[0034] A second typical embodiment of the present invention provides a method for preparing the mica-metal oxide composite nanomaterial described in the first aspect, comprising the following steps:

[0035] (1) Mica powder and nickel powder were ball-milled to obtain a precursor;

[0036] (2) The precursor is calcined in an oxygen atmosphere to obtain the mica-metal oxide composite nanomaterial.

[0037] In one or more embodiments, in step (1), the mass ratio of mica powder to nickel powder is 3:2 to 6, preferably 3:5.

[0038] In one or more embodiments, in step (1), a ball milling aid needs to be added during the ball milling process, and the ball milling aid is ethanol.

[0039] In one or more embodiments, in step (1), during the ball milling process, the ball-to-material ratio is (24~26):(1.8~2.2), preferably 25:2.

[0040] In one or more embodiments, in step (1), during the ball milling process, the rotation speed of the ball mill is 350~500 r / min, preferably 400 r / min; the ball milling time is 7~9 h, preferably 8 h.

[0041] In one or more embodiments, in step (2), the calcination temperature is 550~700 ℃, preferably 600 ℃, and the calcination time is 7~9 h, preferably 8 h.

[0042] Preferably, the heating rate during calcination is 8~12 ℃ / min, more preferably 10 ℃ / min.

[0043] A third typical embodiment of the present invention provides the application of the mica-metal oxide composite nanomaterial described in the first aspect as a catalyst.

[0044] In one or more embodiments, the application includes: producing hydrogen by electrolysis of water.

[0045] A fourth typical embodiment of the present invention provides a catalyst layer slurry for hydrogen production by water electrolysis, comprising a binder, a conductive material, and the mica-metal oxide composite nanomaterial described in the first aspect.

[0046] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0047] Example 1

[0048] Preparation based on mica-metal oxide composite nanomaterials:

[0049] (1) Pretreatment of mica powder: The mica powder was pulverized in a pulverizer; anhydrous ethanol was added to the pulverized mica powder, and the mixture was allowed to stand for 2 hours. The supernatant was centrifuged (15,000 rpm for 8 minutes) and the precipitate was collected. The precipitate was then vacuum dried in a vacuum drying oven at 60 °C to obtain mica powder with a nanoparticle size of 5~8 μm.

[0050] (2) Add 3 g of mica powder obtained in step (1) and 5 g of nickel powder to a ball mill jar, add 20 mL of ethanol as a grinding aid, add zirconium oxide grinding balls with diameters of 5 mm, 8 mm and 10 mm respectively, and a ball-to-material ratio of 25:2, and perform ball milling. The forward rotation time is 30 min, the reverse rotation time is 30 min, the total ball milling time is 8 h, and the rotation speed is 400 r / min.

[0051] The ball-milled sample was placed in a vacuum drying oven and dried at 80 °C for 4 h to obtain the precursor, which was named Ni / Mica.

[0052] (3) The precursor Ni / Mica obtained in step (2) was ground into powder by mortar and pestle. Then, 200 mg of the sample was weighed and evenly spread on a quartz boat. The sample was heated to 600 °C in an air atmosphere at a heating rate of 10 °C / min and calcined for 8 h to obtain mica-metal oxide composite nanomaterial, named NiO / Mica.

[0053] Figure 1 Scanning electron microscope (SEM) images of the mica-metal oxide composite nanomaterial NiO / Mica, from... Figure 1 As can be seen, NiO nanosheets are uniformly distributed on mica powder, avoiding the aggregation of nickel oxide nanoparticles, thus exposing more active sites and improving electrocatalytic performance.

[0054] Figure 2 XRD images of mica powder, the precursor Ni / Mica, and the mica-metal oxide composite nanomaterial NiO / Mica, from... Figure 2 As can be seen, Mica has a high degree of crystallinity. Three characteristic peaks of Mica can be clearly observed at 2θ = 17.8°, 26.8°, and 45.6°, corresponding to the (004), (006), and (224) crystal planes of Mica (26-0911), respectively. Two peaks are observed at 2θ = 27.2° and 43.3°, exhibiting characteristics of the cubic NiO phase (71-1179). Peaks at 2θ = 44.5° and 51.8° represent Ni (04-0850).

[0055] Figure 3 EDX images of the mica-metal oxide composite nanomaterial NiO / Mica, from Figure 3 As can be seen, the distribution of each element is relatively uniform, and Ni can be successfully loaded onto mica, thus ensuring the feasibility of catalysis.

[0056] Example 2

[0057] Add 3 g of mica powder obtained in step (1) of Example 1 and 3 g of nickel powder to a ball mill jar, add 20 mL of ethanol as a grinding aid, add zirconium oxide grinding balls with diameters of 5 mm, 8 mm and 10 mm respectively, and a ball-to-material ratio of 25:2, and perform ball milling. The forward rotation time is 30 min, the reverse rotation time is 30 min, the total ball milling time is 8 h, and the rotation speed is 400 r / min.

[0058] The ball-milled sample was placed in a vacuum drying oven and dried at 80 °C for 4 h to obtain the precursor, which was named Ni / Mica.

[0059] (3) The precursor Ni / Mica obtained in step (2) was ground into powder by mortar and pestle. Then, 200 mg of the sample was weighed and evenly spread on a quartz boat. The sample was heated to 600 °C in an air atmosphere at a heating rate of 10 °C / min and calcined for 8 h to obtain mica-metal oxide composite nanomaterial, named NiO / Mica.

[0060] Example 3

[0061] Add 3 g of mica powder obtained in step (1) of Example and 4 g of nickel powder to a ball mill jar, add 20 mL of ethanol as a grinding aid, add zirconium oxide grinding balls with diameters of 5 mm, 8 mm and 10 mm respectively, and a ball-to-material ratio of 25:2, and perform ball milling treatment. The forward rotation time is 30 min, the reverse rotation time is 30 min, the total ball milling time is 8 h, and the rotation speed is 400 r / min.

[0062] The ball-milled sample was placed in a vacuum drying oven and dried at 80 °C for 4 h to obtain the precursor, which was named Ni / Mica.

[0063] The precursor Ni / Mica obtained in step (2) was ground into powder using a mortar and pestle. Then, 200 mg of the sample was weighed and evenly spread on a quartz boat. The sample was then heated to 600 °C in an air atmosphere at a heating rate of 10 °C / min and calcined for 8 h to obtain mica-metal oxide composite nanomaterials, which were named NiO / Mica.

[0064] Example 4

[0065] Add 3 g of mica powder obtained in step (1) of Example and 6 g of nickel powder to a ball mill jar, add 20 mL of ethanol as a grinding aid, add zirconium oxide grinding balls with diameters of 5 mm, 8 mm and 10 mm respectively, and a ball-to-material ratio of 25:2, and perform ball milling treatment. The forward rotation time is 30 min, the reverse rotation time is 30 min, the total ball milling time is 8 h, and the rotation speed is 400 r / min.

[0066] The ball-milled sample was placed in a vacuum drying oven and dried at 80 °C for 4 h to obtain the precursor, which was named Ni / Mica.

[0067] The precursor Ni / Mica obtained in step (2) was ground into powder using a mortar and pestle. Then, 200 mg of the sample was weighed and evenly spread on a quartz boat. The sample was then heated to 600 °C in an air atmosphere at a heating rate of 10 °C / min and calcined for 8 h to obtain mica-metal oxide composite nanomaterials, which were named NiO / Mica.

[0068] Example 5

[0069] Add 3 g of mica powder obtained in step (1) of Example and 7 g of nickel powder to a ball mill jar, add 20 mL of ethanol as a grinding aid, add zirconium oxide grinding balls with diameters of 5 mm, 8 mm and 10 mm respectively, and a ball-to-material ratio of 25:2, and perform ball milling treatment. The forward rotation time is 30 min, the reverse rotation time is 30 min, the total ball milling time is 8 h, and the rotation speed is 400 r / min.

[0070] The ball-milled sample was placed in a vacuum drying oven and dried at 80 °C for 4 h to obtain the precursor, which was named Ni / Mica.

[0071] The precursor Ni / Mica obtained in step (2) was ground into powder using a mortar and pestle. Then, 200 mg of the sample was weighed and evenly spread on a quartz boat. The sample was then heated to 600 °C in an air atmosphere at a heating rate of 10 °C / min and calcined for 8 h to obtain mica-metal oxide composite nanomaterials, which were named NiO / Mica.

[0072] Example 6

[0073] Add 3 g of mica powder obtained in step (1) of Example and 8 g of nickel powder to a ball mill jar, add 20 mL of ethanol as a grinding aid, add zirconium oxide grinding balls with diameters of 5 mm, 8 mm and 10 mm respectively, and a ball-to-material ratio of 25:2, and perform ball milling treatment. The forward rotation time is 30 min, the reverse rotation time is 30 min, the total ball milling time is 8 h, and the rotation speed is 400 r / min.

[0074] The ball-milled sample was placed in a vacuum drying oven and dried at 80 °C for 4 h to obtain the precursor, which was named Ni / Mica.

[0075] The precursor Ni / Mica obtained in step (2) was ground into powder using a mortar and pestle. Then, 200 mg of the sample was weighed and evenly spread on a quartz boat. The sample was then heated to 600 °C in an air atmosphere at a heating rate of 10 °C / min and calcined for 8 h to obtain mica-metal oxide composite nanomaterials, which were named NiO / Mica.

[0076] Example 7

[0077] The precursor Ni / Mica obtained in step (2) of Example 1 was ground into powder using a mortar and pestle. Then, 200 mg of the sample was weighed and evenly spread on a quartz boat. The sample was then heated to 550 °C in an air atmosphere at a heating rate of 10 °C / min and calcined for 9 h to obtain mica-metal oxide composite nanomaterials, which were named NiO / Mica.

[0078] Example 8

[0079] The precursor Ni / Mica obtained in step (2) of Example 1 was ground into powder using a mortar and pestle. Then, 200 mg of the sample was weighed and evenly spread on a quartz boat. The sample was then heated to 700 °C in an air atmosphere at a heating rate of 10 °C / min and calcined for 7 h to obtain mica-metal oxide composite nanomaterials, named NiO / Mica.

[0080] Example 9

[0081] Two mg of the mica-metal oxide composite nanomaterial NiO / Mica prepared in Example 1 and eight mg of carbon powder were dispersed in 1.5 mL of isopropanol, and 0.5 mL of Nafion solution (0.5 wt%) was added. The mixture was sonicated for 30 min until a homogeneous catalyst slurry was formed. A 1×1 cm piece of nickel-iron foam (5:5) was cut as a substrate, and the catalyst slurry was evenly brushed onto the surface of the nickel-iron foam substrate to form a working electrode for electrochemical performance testing. In a three-electrode system at room temperature, an electrochemical workstation was used, with a graphite rod and Ag / AgCl (4.0 M KCl) as the counter electrode and reference electrode, respectively, and 1 M KOH as the electrolyte.

[0082] Figure 4 OER polarization curves of nickel-iron foam substrate, mica powder, precursor Ni / Mica, mica-metal oxide composite nanomaterials NiO / Mica and RuO2 are shown. Figure 4 As can be seen, the mica-metal oxide composite nanomaterial NiO / Mica exhibits particularly outstanding activity, requiring only 270mV overpotential to reach 10mA cm⁻¹. -2 It is higher than other materials (RuO2 is 295mV, Ni / Mica is 320mV, Mica is 321mV, and pure substrate is 355mV).

[0083] To gain a deeper understanding of the OER reaction pathway, the Tafel slopes of the OER polarization curves for various catalysts (foamed nickel-iron substrate, mica powder, precursor Ni / Mica, mica-metal oxide composite nanomaterials NiO / Mica, and RuO2) are shown below. Figure 5 As shown, from Figure 5 It is quite evident that, compared to the substrate (260.9 mV dec), -1 Mica (196.1 mV dec) -1 Ni / Mica (176.2 mV dec) -1 ), RuO2 (102.3 mV dec) -1 ), mica-metal oxide composite nanomaterial NiO / Mica (51.2 mV dec) -1 The NiO / Mica electrode exhibits a smaller Tafel slope, indicating that it possesses superior intrinsic catalytic activity compared to other electrodes.

[0084] Electrochemical impedance spectroscopy was performed on the electrodes of various catalysts (foamed nickel-iron substrate, mica powder, precursor Ni / Mica, mica-metal oxide composite nanomaterial NiO / Mica, and RuO2) to further study the catalytic kinetics. Figure 6As shown, the similar semicircular curves among different samples indicate similar electrochemical mechanisms and charge transfer characteristics. A linear correlation exists between the charge transfer resistance (Rct) and the semicircular diameter of the Nyquist curve. Through fitting, it is found that the NiO / Mica electrode has the smallest Rct value of 1.7 Ω, reflecting its faster charge transfer kinetics, consistent with the overpotential and Tafel slope mentioned earlier.

[0085] Example 10

[0086] Besides excellent catalytic activity, stability is another important factor in evaluating the quality of a catalyst. The stability test of the NiO / Mica electrode was conducted in an O2-saturated 1.0 M KOH solution, with a constant current density of 10 mAcm⁻¹ applied to the electrode. -2 To perform long-loop testing, such as Figure 7 As shown. After 111 hours of testing, the overpotential of the electrode prepared in Example 9 did not increase significantly, indicating its excellent stability.

[0087] Example 11

[0088] To gain a deeper understanding of the effect of Ni content on catalytic activity, only the mass of Ni was varied while keeping other conditions constant. The polarization curves of the working electrodes and substrates prepared according to the electrode preparation method in Example 9 for NiO / Mica composite nanomaterials with different mica and nickel powder ratios prepared in Examples 1-6 are shown below. Figure 8 As shown, it is clear that the sample in Example 1 has the best catalytic activity, indicating that the ratio of mica to nickel powder affects the final catalytic activity.

Claims

1. A method for preparing mica-metal oxide composite nanomaterials, characterized in that, Includes the following steps: (1) Mica powder and nickel powder were ball-milled to obtain a precursor; (2) The precursor is calcined in an oxygen atmosphere to obtain the mica-metal oxide composite nanomaterial; In step (1), the mass ratio of mica powder to nickel powder is 3:2~6.

2. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of mica powder to nickel powder is 3:

5.

3. The preparation method according to claim 1, characterized in that, In step (1), a ball milling aid needs to be added during the ball milling process, and the ball milling aid is ethanol.

4. The preparation method according to claim 1, characterized in that, In step (1), during the ball milling process, the ball-to-material ratio is (24~26):(1.8~2.2). Alternatively, in step (1), during the ball milling process, the rotation speed of the ball mill is 350~500 r / min; the ball milling time is 7~9 h.

5. The preparation method according to claim 1, characterized in that, In step (1), the ball-to-material ratio is 25:2 during the ball milling process.

6. The preparation method according to claim 1, characterized in that, In step (1), the ball milling speed is 400 r / min and the ball milling time is 8 h.

7. The preparation method according to claim 1, characterized in that, In step (2), the calcination temperature is 550~700 ℃ and the calcination time is 7~9 h.

8. The preparation method according to claim 1, characterized in that, In step (2), the calcination temperature is 600 ℃ and the calcination time is 8 h.

9. The preparation method according to claim 1, characterized in that, In step (2), the heating rate during calcination is 8~12 ℃ / min.

10. The preparation method according to claim 1, characterized in that, In step (2), the heating rate during calcination is 10℃ / min.

11. The mica-metal oxide composite nanomaterial obtained by the preparation method according to any one of claims 1-10, characterized in that, It uses mica powder as a carrier and loads nickel oxide nanoparticles.

12. The mica-metal oxide composite nanomaterial as described in claim 11, characterized in that, The particle size of the mica powder is 5~8 μm; Nickel oxide nanoparticles are nanosheets with a particle size of 1~2 μm.

13. The application of the mica-metal oxide composite nanomaterial according to claim 11 or 12 as a catalyst.

14. The application as described in claim 13, characterized in that, The applications include: hydrogen production via water electrolysis.

15. A catalyst slurry for hydrogen production by water electrolysis, characterized in that, Includes binders, conductive materials, and the mica-metal oxide composite nanomaterials as described in claim 11 or 12.

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