Composite electrode material and preparation method and application thereof

Abstract

The application relates to the technical field of electrolytic water oxygen production, in particular to a composite electrode material and a preparation method and application thereof. The preparation method of the composite electrode material comprises the following steps: roughening the surface of a stainless steel mesh by performing first CV activation on the stainless steel mesh in a KOH solution, releasing Cr 3+ ions in the stainless steel mesh 3+ ions, and obtaining the stainless steel mesh after CV activation; performing second CV activation on the stainless steel mesh after CV activation in a Ni 2+ ion solution, forming Cr-doped nickel-iron hydroxide covering the surface of the stainless steel mesh, and obtaining the composite electrode material. The Cr-doped nickel-iron hydroxide loaded on the surface of the stainless steel mesh obtained by the preparation method can solve the technical problems of iron element dissolution, deactivation and active stability decline of the existing nickel-iron hydroxide in a long-period oxygen evolution process.

Description

Technical Field

[0001] This invention relates to the field of water electrolysis for oxygen production, specifically to a composite electrode material, its preparation method, and its application. Background Technology

[0002] Nickel-iron hydroxide (NiFeHb) is an important electrochemical energy conversion and storage material composed of elements such as nickel, iron, hydrogen, and oxygen. It possesses a high specific surface area, abundant pore structure, and excellent electrochemical performance. Due to its superior catalytic performance in water electrolysis for oxygen production, NiFeHb's application in this field has attracted widespread attention.

[0003] Traditional nickel-iron hydroxides (NiFeHb) are typically nickel-based supported catalysts. During long-term water electrolysis for oxygen production, they suffer from iron dissolution, loss, and performance degradation, severely impacting their lifespan. To address these issues, existing technologies have proposed using foamed iron as a carrier to support NiFeHb catalysts. This method continuously replenishes the catalyst surface with iron via foamed iron, mitigating iron dissolution and loss. However, during water electrolysis for oxygen production, iron in foamed iron undergoes its own redox reaction, resulting in rust formation and damage to the active center structure of the NiFeHb, further degrading its performance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a composite electrode material, its preparation method and application, which solves the technical problems of iron dissolution, deactivation and decreased activity stability of existing nickel-iron hydroxides during long-term oxygen evolution.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a composite electrode material and its preparation method, comprising the following steps:

[0007] The stainless steel mesh was subjected to a first CV activation in KOH solution to achieve surface roughening treatment and release the Cr inside the stainless steel mesh. 3+ Ions and Fe 3+ Ions were used to prepare stainless steel mesh after CV activation; in Ni 2+ In an ionic solution, a second CV activation is performed on a stainless steel mesh that has already undergone CV activation, forming a Cr-doped nickel-iron hydroxide covering the surface of the stainless steel mesh, thus obtaining a composite electrode material.

[0008] The Cr inside the stainless steel mesh is released through the first CV activation. 3+ Ions and Fe 3+The surface of the ion-doped nickel-iron hydroxide nanosheets is roughened to facilitate the generation of Cr-doped nickel-iron hydroxide nanosheets loaded on the surface of a stainless steel mesh via a second CV activation process. Using stainless steel as the carrier for the composite electrode material mitigates the catalyst detachment due to rusting that occurs with foamed iron mesh. Furthermore, the stainless steel mesh acts as an iron source, replenishing the iron in the Cr-doped nickel-iron hydroxide in real time. This effectively addresses the problem of reduced catalyst stability caused by iron dissolution and loss during water electrolysis for oxygen production, thus resolving the technical issues of iron dissolution, deactivation, and decreased activity stability in existing nickel-iron hydroxides during long-term oxygen evolution processes.

[0009] Optionally, the potential range of the first CV activation is -0.34V to 0.24V vs. RHE, and the number of activation cycles is 5 to 30.

[0010] Optionally, the concentration of the KOH solution is 0 mol / L to 0.2 mol / L.

[0011] Optionally, the potential range of the second CV activation is 1V to 1.6V vs. RHE, and the number of activation cycles is 5 to 80.

[0012] Optionally, Ni 2+ The concentration of the ionic solution is 0 mol / L to 0.5 mol / L.

[0013] Optionally, the stainless steel mesh has a mesh count of 100 to 400. Common stainless steel materials such as 201 and 316 stainless steel can meet the requirements for stainless steel mesh. Therefore, this invention does not limit the specific stainless steel type. However, considering the rust prevention requirements and application costs of stainless steel mesh in actual use, 304 stainless steel is preferred as the material for the stainless steel mesh.

[0014] This invention provides a composite electrode material prepared using the aforementioned method.

[0015] This invention provides an application of a composite electrode material as an electrode in hydrogen production through water electrolysis.

[0016] The beneficial effect of this invention is that, compared with the prior art, the release of Cr inside the stainless steel mesh through the first CV activation is achieved. 3+ Ions and Fe 3+The surface of the ion-doped nickel-iron hydroxide nanosheets is roughened to facilitate the generation of Cr-doped nickel-iron hydroxide nanosheets loaded on the surface of a stainless steel mesh via a second CV activation process. Using stainless steel as the carrier for the composite electrode material mitigates the catalyst detachment due to rusting that occurs with foamed iron mesh. Furthermore, the stainless steel mesh acts as an iron source, replenishing the iron in the Cr-doped nickel-iron hydroxide in real time. This effectively addresses the problem of decreased stability of nickel-iron hydroxide due to iron dissolution and loss during water electrolysis for oxygen production, thus resolving the existing technical issues of iron dissolution, deactivation, and decreased activity stability in nickel-iron hydroxides during long-term oxygen evolution processes.

[0017] Furthermore, the Cr in Cr-doped nickel-iron hydroxide can form local Lewis acid sites with surrounding O atoms and promote the formation of OH groups in the electrolyte. - Adsorbed on the surface of nickel-iron hydroxide, it increases the local pH value on the catalyst surface, thereby accelerating the intrinsic activity of the water electrolysis to produce hydrogen reaction. Attached Figure Description

[0018] Figure 1 A scanning electron microscope image of the stainless steel mesh in Embodiment 1 of the present invention.

[0019] Figure 2 Scanning electron microscope image of the stainless steel mesh prepared by CV activation in Example 1 of the present invention.

[0020] Figure 3 The image shows a scanning electron microscope (SEM) image of the composite electrode material prepared in Example 1 of this invention.

[0021] Figure 4 The current-voltage curve test diagrams of the composite electrode materials prepared in Examples 1 to 5 and Comparative Example 1 provided by the present invention.

[0022] Figure 5 The current-voltage curve test diagrams of the composite electrode materials prepared in Examples 1 and 9 to 11 of the present invention.

[0023] Figure 6 The image shows the voltammetric curves of the stainless steel mesh in Example 1 of this invention, and the CV-activated stainless steel mesh and composite electrode material prepared in Example 1.

[0024] Figure 7 This is an elemental analysis diagram of the composite electrode material prepared in Example 1 of the present invention.

[0025] Figure 8This is a distribution diagram of different elements in the composite electrode material prepared in Example 1 of the present invention. Among them, a) is the distribution diagram of Fe, b) is the distribution diagram of Ni, c) is the distribution diagram of Cr, and d) is the distribution diagram of O. Detailed Implementation

[0026] To address the aforementioned technical problems, this invention provides a composite electrode material and its preparation method. The technical solution and embodiments of this invention will now be described in detail with reference to the accompanying drawings.

[0027] The present invention will now be described in detail through specific embodiments. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0028] Example 1

[0029] This embodiment provides a composite electrode material and its preparation method, the specific steps of which are as follows:

[0030] The stainless steel mesh was subjected to a first CV activation in a 0.1 mol / L KOH solution to achieve surface roughening treatment and release the Cr inside the stainless steel mesh. 3+ Ions and Fe 3+ Ions were used to prepare a stainless steel mesh after CV activation. The potential range of the first CV activation was -0.34V to 0.24V vs. RHE, and the number of activation cycles was 15.

[0031] A second CV activation was performed on a stainless steel mesh that had already undergone CV activation in a 0.1 mol / L nickel sulfate solution, forming a Cr-doped nickel-iron hydroxide coating on the surface of the stainless steel mesh, thus preparing a composite electrode material. The potential range for the second CV activation was 1 V–1.6 V vs. RHE, and the number of activation cycles was 50. 。

[0032] Example 2

[0033] The difference from Example 1 is that the concentration of the KOH solution is 0.001 mol / L.

[0034] This embodiment provides a composite electrode material and its preparation method, the specific steps of which are as follows:

[0035] The stainless steel mesh was subjected to a first CV activation in a 0.001 mol / L KOH solution to achieve surface roughening treatment and release the Cr inside the stainless steel mesh. 3+ Ions and Fe 3+ Ions were used to prepare a stainless steel mesh after CV activation. The potential range of the first CV activation was -0.34V to 0.24V vs. RHE, and the number of activation cycles was 15.

[0036] A second CV activation was performed on a stainless steel mesh that had already undergone CV activation in a 0.1 mol / L nickel sulfate solution, forming a Cr-doped nickel-iron hydroxide coating on the surface of the stainless steel mesh, thus preparing a composite electrode material. The potential range for the second CV activation was 1 V–1.6 V vs. RHE, and the number of activation cycles was 50. 。

[0037] Example 3

[0038] The difference from Example 1 is that the concentration of the KOH solution is 0.01 mol / L.

[0039] This embodiment provides a composite electrode material and its preparation method, the specific steps of which are as follows:

[0040] The stainless steel mesh was subjected to a first CV activation in a 0.01 mol / L KOH solution to achieve surface roughening and release the Cr inside the stainless steel mesh. 3+ Ions and Fe 3+ Ions were used to prepare a stainless steel mesh after CV activation. The potential range of the first CV activation was -0.34V to 0.24V vs. RHE, and the number of activation cycles was 15.

[0041] A second CV activation was performed on a stainless steel mesh that had already undergone CV activation in a 0.1 mol / L nickel sulfate solution, forming a Cr-doped nickel-iron hydroxide coating on the surface of the stainless steel mesh, thus preparing a composite electrode material. The potential range for the second CV activation was 1 V–1.6 V vs. RHE, and the number of activation cycles was 50. 。

[0042] Example 4

[0043] The difference from Example 1 is that the concentration of the KOH solution is 0.05 mol / L.

[0044] This embodiment provides a composite electrode material and its preparation method, the specific steps of which are as follows:

[0045] The stainless steel mesh was subjected to a first CV activation in a 0.05 mol / L KOH solution to achieve surface roughening treatment and release the Cr inside the stainless steel mesh. 3+ Ions and Fe 3+ Ions were used to prepare a stainless steel mesh after CV activation. The potential range of the first CV activation was -0.34V to 0.24V vs. RHE, and the number of activation cycles was 15.

[0046] A second CV activation was performed on a stainless steel mesh that had already undergone CV activation in a 0.1 mol / L nickel sulfate solution, forming a Cr-doped nickel-iron hydroxide coating on the surface of the stainless steel mesh, thus preparing a composite electrode material. The potential range for the second CV activation was 1 V–1.6 V vs. RHE, and the number of activation cycles was 50. 。

[0047] Example 5

[0048] The difference from Example 1 is that the concentration of the KOH solution is 0.5 mol / L.

[0049] This embodiment provides a composite electrode material and its preparation method, the specific steps of which are as follows:

[0050] The stainless steel mesh was subjected to a first CV activation in a 0.5 mol / L KOH solution to achieve surface roughening treatment and release the Cr inside the stainless steel mesh. 3+ Ions and Fe 3+ Ions were used to prepare a stainless steel mesh after CV activation. The potential range of the first CV activation was -0.34V to 0.24V vs. RHE, and the number of activation cycles was 15.

[0051] A second CV activation was performed on a stainless steel mesh that had already undergone CV activation in a 0.1 mol / L nickel sulfate solution, forming a Cr-doped nickel-iron hydroxide coating on the surface of the stainless steel mesh, thus preparing a composite electrode material. The potential range for the second CV activation was 1 V–1.6 V vs. RHE, and the number of activation cycles was 50. 。

[0052] Example 6

[0053] The difference from Example 1 is that the concentration of the nickel sulfate solution is 0.5 mol / L.

[0054] This embodiment provides a composite electrode material and its preparation method, the specific steps of which are as follows:

[0055] The stainless steel mesh was subjected to a first CV activation in a 0.1 mol / L KOH solution to achieve surface roughening treatment and release the Cr inside the stainless steel mesh. 3+ Ions and Fe 3+ Ions were used to prepare a stainless steel mesh after CV activation. The potential range of the first CV activation was -0.34V to 0.24V vs. RHE, and the number of activation cycles was 15.

[0056] A second CV activation was performed on a stainless steel mesh that had already undergone CV activation in a 0.5 mol / L nickel sulfate solution, forming a Cr-doped nickel-iron hydroxide coating on the surface of the stainless steel mesh, thus preparing a composite electrode material. The potential range for the second CV activation was 1 V–1.6 V vs. RHE, and the number of activation cycles was 50. 。

[0057] Example 7

[0058] The difference from Example 1 is that the number of activation cycles for the first CV activation is 5.

[0059] This embodiment provides a composite electrode material and its preparation method, the specific steps of which are as follows:

[0060] The stainless steel mesh was subjected to a first CV activation in a 0.1 mol / L KOH solution to achieve surface roughening treatment and release the Cr inside the stainless steel mesh. 3+ Ions and Fe 3+ Ions were used to prepare a stainless steel mesh after CV activation. The potential range of the first CV activation was -0.34V to 0.24V vs. RHE, and the number of activation cycles was 5.

[0061] A second CV activation was performed on a stainless steel mesh that had already undergone CV activation in a 0.1 mol / L nickel sulfate solution, forming a Cr-doped nickel-iron hydroxide coating on the surface of the stainless steel mesh, thus preparing a composite electrode material. The potential range for the second CV activation was 1 V–1.6 V vs. RHE, and the number of activation cycles was 50. 。

[0062] Example 8

[0063] The difference from Example 1 is that the number of activation cycles for the first CV activation is 30 cycles.

[0064] This embodiment provides a composite electrode material and its preparation method, the specific steps of which are as follows:

[0065] The stainless steel mesh was subjected to a first CV activation in a 0.1 mol / L KOH solution to achieve surface roughening treatment and release the Cr inside the stainless steel mesh. 3+ Ions and Fe 3+ Ions were used to prepare a stainless steel mesh after CV activation. The potential range of the first CV activation was -0.34V to 0.24V vs. RHE, and the number of activation cycles was 30.

[0066] A second CV activation was performed on a stainless steel mesh that had already undergone CV activation in a 0.1 mol / L nickel sulfate solution, forming a Cr-doped nickel-iron hydroxide coating on the surface of the stainless steel mesh, thus preparing a composite electrode material. The potential range for the second CV activation was 1 V–1.6 V vs. RHE, and the number of activation cycles was 50. 。

[0067] Example 9

[0068] The difference from Example 1 is that the second CV activation cycle is 5 cycles.

[0069] This embodiment provides a composite electrode material and its preparation method, the specific steps of which are as follows:

[0070] The stainless steel mesh was subjected to a first CV activation in a 0.1 mol / L KOH solution to achieve surface roughening treatment and release the Cr inside the stainless steel mesh. 3+ Ions and Fe 3+ Ions were used to prepare a stainless steel mesh after CV activation. The potential range of the first CV activation was -0.34V to 0.24V vs. RHE, and the number of activation cycles was 15.

[0071] A second CV activation was performed on a stainless steel mesh that had already undergone CV activation in a 0.1 mol / L nickel sulfate solution, forming a Cr-doped nickel-iron hydroxide coating on the surface of the stainless steel mesh, thus preparing a composite electrode material. The potential range for the second CV activation was 1 V–1.6 V vs. RHE, and the number of activation cycles was 5. 。

[0072] Example 10

[0073] The difference from Example 1 is that the second CV activation cycle is 15 cycles.

[0074] This embodiment provides a composite electrode material and its preparation method, the specific steps of which are as follows:

[0075] The stainless steel mesh was subjected to a first CV activation in a 0.1 mol / L KOH solution to achieve surface roughening treatment and release the Cr inside the stainless steel mesh. 3+ Ions and Fe 3+ Ions were used to prepare a stainless steel mesh after CV activation. The potential range of the first CV activation was -0.34V to 0.24V vs. RHE, and the number of activation cycles was 15.

[0076] A second CV activation was performed on a stainless steel mesh that had already undergone CV activation in a 0.1 mol / L nickel sulfate solution, forming a Cr-doped nickel-iron hydroxide coating on the surface of the stainless steel mesh, thus preparing a composite electrode material. The potential range for the second CV activation was 1 V–1.6 V vs. RHE, and the number of activation cycles was 15. 。

[0077] Example 11

[0078] The difference from Example 1 is that the second CV activation cycle is 80 cycles.

[0079] This embodiment provides a composite electrode material and its preparation method, the specific steps of which are as follows:

[0080] The stainless steel mesh was subjected to a first CV activation in a 0.1 mol / L KOH solution to achieve surface roughening treatment and release the Cr inside the stainless steel mesh. 3+ Ions and Fe 3+ Ions were used to prepare a stainless steel mesh after CV activation. The potential range of the first CV activation was -0.34V to 0.24V vs. RHE, and the number of activation cycles was 15.

[0081] A second CV activation was performed on a stainless steel mesh that had already undergone CV activation in a 0.1 mol / L nickel sulfate solution, forming a Cr-doped nickel-iron hydroxide coating on the surface of the stainless steel mesh, thus preparing a composite electrode material. The potential range for the second CV activation was 1 V–1.6 V vs. RHE, and the number of activation cycles was 80. 。

[0082] It should be noted that, compared with Example 1, the catalytic performance of the composite electrode materials prepared in Examples 2 to 11 is not significantly different.

[0083] Comparative Example 1

[0084] The difference from Example 1 is that the concentration of the KOH solution is 0 mol / L, that is, pure water is used instead of KOH solution.

[0085] Surface morphology and performance characterization tests and test results:

[0086] The stainless steel mesh in Example 1 is labeled as SSM, the stainless steel mesh after CV activation is labeled as CV-SSM, and the composite electrode material is labeled as NiFe-CV-SSM.

[0087] The morphology and structure of the prepared samples were characterized using scanning electron microscopy (SEM), among which, Figure 1 This is an SEM image of an unactivated stainless steel mesh. It can be seen that the surface of the unactivated stainless steel is relatively smooth.

[0088] Figure 2 This is a SEM image of the CV-SSM catalyst obtained after the first CV activation. The roughening of the stainless steel mesh surface is beneficial for Cr... 3+ and Fe 3+ The release.

[0089] Figure 3 This is a SEM image of NiFe-CV-SSM obtained after the second CV activation. It can be seen that a nickel-iron hydroxide oxide layer with a nanosheet structure is clearly grown on the surface.

[0090] All LSV tests below were conducted at room temperature, with 0.1M KOH solution as the electrolyte.

[0091] Figure 4 The current-voltage curve test diagrams of the composite electrode materials prepared in Examples 1 to 5 and Comparative Example 1 of this invention are shown below. Figure 4 Compared to Comparative Example 1, the alkaline oxygen evolution performance of the composite electrode materials prepared in Examples 1 to 5 was improved. Among them, the composite electrode material prepared in Example 1 showed the best alkaline oxygen evolution performance.

[0092] Figure 5 The current-voltage curve test diagrams of the composite electrode materials prepared in Examples 1 and 9 to 11 of this invention are shown below. Figure 5 As shown, the composite electrode material prepared with 50 activation cycles in the second activation cycle exhibited the best alkaline oxygen evolution performance.

[0093] The sample prepared in Example 1 was subjected to LSV testing. Figure 6 It can be seen that, compared with SSM and CV-SSM, the NiFe-CV-SSM catalyst obtained after two activations has significantly better alkaline oxygen evolution performance than SSM and CV-SSM.

[0094] Figure 7 This is the elemental analysis diagram of the composite electrode material prepared in Example 1 of the present invention. Figure 8 This is a distribution diagram of different elements in the composite electrode material prepared in Example 1 of the present invention. Combined with... Figure 7 and Figure 8 It can be seen that chromium, iron, nickel and oxygen elements are uniformly distributed on the surface of the NiFe-CV-SSM catalyst.

[0095] The above description is merely a preferred embodiment of the present invention, and the specific embodiments described above are not intended to limit the present invention. Various modifications and variations can be made within the scope of the technical concept of the present invention. All refinements, modifications, or equivalent substitutions made by those skilled in the art based on the above description are within the scope of protection of the present invention.

Claims

1. A method for preparing a composite electrode material, characterized in that, Includes the following steps: The stainless steel mesh was subjected to a first CV activation in KOH solution to achieve surface roughening treatment and release the Cr inside the stainless steel mesh. 3+ Ions and Fe 3+ Ions were used to prepare stainless steel mesh after CV activation; In Ni 2+ In an ionic solution, a second CV activation is performed on a stainless steel mesh that has already undergone CV activation, forming a Cr-doped nickel-iron hydroxide covering the surface of the stainless steel mesh, thus obtaining a composite electrode material.

2. The method for preparing the composite electrode material according to claim 1, characterized in that, The potential range for the first CV activation is -0.34V to 0.24V vs. RHE, and the number of activation cycles is 5 to 30.

3. The method for preparing the composite electrode material according to claim 2, characterized in that, The concentration of the KOH solution is 0.001 mol / L to 0.5 mol / L.

4. The method for preparing the composite electrode material according to claim 1, characterized in that, The potential range for the second CV activation is 1V to 1.6V vs. RHE, and the number of activation cycles is 5 to 80.

5. The method for preparing the composite electrode material according to claim 4, characterized in that, Ni 2+ The concentration of the ionic solution is 0.1 mol / L to 0.5 mol / L.

6. The method for preparing the composite electrode material according to claim 1, characterized in that, The stainless steel mesh has a mesh count of 100 to 400.

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