Corrosion-resistant long-life titanium electrode and preparation method and application thereof

Abstract

The invention discloses a corrosion-resistant long-life titanium electrode and a preparation method and application thereof.The corrosion-resistant long-life titanium electrode is characterized in that a titanium plate serves as a base body, a Ti-C composite barrier layer, a Mn-Co-Ce-based active layer and a Si-Ni-based composite protective layer are sequentially arranged on the surface of the titanium base body from inside to outside, and a three-layer functional gradient composite structure from the base body to the surface is formed. The Ti-C layer is tough and tough in combination, the Mn-Co-Ce layer is stable in catalysis, the Si-Ni layer is efficient in protection, the three layers perform their own functions and cooperate with one another, and a complete protection system from an interface to a bulk phase and then to the surface is constructed. On the basis of core elements, more than twenty optional elements are introduced in an open manner, and the interaction among the elements is utilized, so that the refined regulation and control and limit improvement of the performance are realized, and the performance bottleneck of modification of a single element or a small amount of elements is broken through.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical electrode materials technology, and relates to a corrosion-resistant, long-life titanium electrode, its preparation method and application, and particularly to a preparation technology of a titanium-based manganese dioxide electrode with an ultra-long life through a three-layer gradient composite structure design. Background Technology

[0002] Titanium-based manganese dioxide electrodes have shown application potential in hydrometallurgy (such as the electrowinning of zinc, copper, manganese, nickel, and cobalt) and water electrolysis for hydrogen production due to their relatively low cost, environmental friendliness, and good oxygen evolution catalytic activity. However, their commercial application still faces three major technical bottlenecks:

[0003] 1. Weak interfacial bonding: The thermal expansion coefficients of manganese dioxide and titanium substrate differ significantly, which can easily generate huge internal stress under thermal cycling conditions, leading to coating cracking and peeling.

[0004] 2. Manganese dissolution instability: In strongly acidic working environments, manganese dioxide, especially Mn(III) species, is prone to disproportionation reactions (2Mn³⁺ → Mn²⁺ + Mn). 4 (⁺) or chemical dissolution leads to thinning of the active layer, increased resistance, and decreased catalytic activity.

[0005] 3. Limitations of traditional modification: Existing improvement techniques, such as element doping (Co, Bi, etc.) or the introduction of intermediate layers (such as PbO2, SnO2), can improve certain performance aspects to a certain extent, but they often cannot achieve a balance between high bonding strength, high catalytic activity and ultra-long lifetime. Especially under extreme conditions such as high temperature, high current density and the presence of corrosive ions (such as Cl⁻, F⁻), the lifetime is still not ideal.

[0006] Therefore, developing a new method for preparing titanium electrodes that can systematically and multi-level synergistically strengthen the process from interface bonding and bulk stability to surface protection is of great scientific and engineering significance. Summary of the Invention

[0007] To address the problems of "poor adhesion, rapid manganese dissolution, and short lifespan" in the background technology of titanium-based manganese dioxide electrodes, the present invention aims to provide a corrosion-resistant, long-life titanium electrode, its preparation method, and its application. This method designs a gradient structure with three functionally distinct layers: a Ti-C composite barrier layer, a Mn-Co-Ce-based active layer, and a Si-Ni-based composite protective layer. Multiple elements are introduced for synergistic modification, aiming to simultaneously solve the three core problems of easy coating peeling, rapid manganese dissolution, and short lifespan, thereby achieving a breakthrough improvement in the overall performance of the electrode.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] This invention provides a corrosion-resistant and long-life titanium electrode, which uses a titanium plate as a substrate. From the inside to the outside, a Ti-C composite barrier layer, a Mn-Co-Ce-based active layer and a Si-Ni-based composite protective layer are sequentially disposed on the surface of the titanium substrate, forming a three-layer gradient composite structure from the substrate to the surface.

[0010] In a preferred embodiment, the thickness of the Ti-C composite barrier layer is 10~50μm. This composite barrier layer may also incorporate one or more elements selected from Sn, Sb, Zr, Ir, Ta, Ru, Pt, Co, Mo, W, V, Nb, Cr, Fe, Al, Y, La, and Ce. The addition of these elements can achieve solid solution strengthening, form high-hardness carbides, improve wettability, regulate the coefficient of thermal expansion, and enhance oxidation resistance. The Ti-C composite barrier layer provides an ultra-high strength metallurgical bond with the titanium matrix and serves as a conductive intermediate layer.

[0011] In a preferred embodiment, the thickness of the Mn-Co-Ce-based active layer is 50~150 μm. This active layer may also incorporate one or more elements selected from Ni, Bi, Ag, Au, Pd, Li, Na, K, Mg, Ca, Sr, Ba, B, Ga, In, Ge, Sn, and Sb. Multi-element doping can synergistically regulate the band structure of manganese dioxide, increase oxygen vacancy concentration, stabilize the crystal structure, improve electronic conductivity, and inhibit the dissolution of manganese ions. The Mn-Co-Ce-based active layer serves as the main catalytic active layer of the electrode, providing active sites for the oxygen evolution reaction.

[0012] In a preferred embodiment, the Si-Ni-based composite protective layer has a thickness of 2-10 μm. This protective layer may also incorporate one or more elements selected from F, P, N, C, Al, Zn, Ti, Zr, Ce, La, Y, B, W, Mo, and V. The introduction of these elements can optimize the density, adhesion, acid resistance, conductivity, and impermeability of the protective layer. For example, F can enhance acid resistance, P and B can lower the sintering temperature, and N and C can form an amorphous network to enhance stability. As the outermost physicochemical barrier, the Si-Ni-based composite protective layer prevents electrolyte penetration and inhibits active layer corrosion and manganese dissolution.

[0013] This invention also provides a method for preparing a corrosion-resistant, long-life titanium electrode, comprising the following steps:

[0014] (1) Preparation of Ti-C composite barrier layer: A composite barrier layer mainly composed of Ti and C elements was formed on the surface of the titanium substrate by a combination of laser cladding and electrical discharge deposition process.

[0015] (2) Preparation of Mn-Co-Ce-based active layer: A manganese dioxide-based active layer with Mn, Co, Ce and O elements as the main components is formed on the Ti-C composite barrier layer by slurry coating and microwave-assisted thermal sintering technology.

[0016] (3) Preparation of Si-Ni based composite protective layer: The sol-gel method was used to form a composite protective layer mainly composed of Si, Ni and O elements on the surface of the Mn-Co-Ce based active layer.

[0017] In some preferred embodiments, in step (1), the alloy powder used for laser cladding is a mixture of Ti powder and graphite powder, or Ti-C based alloy powder; the reinforcing phase powder used for electrical discharge deposition is one or more of WC-Co, TiC, and Cr3C2.

[0018] Furthermore, Ti-C based alloy powder is clad onto a titanium substrate using laser cladding technology to form an initial bonding layer. Subsequently, WC-Co hard nanoparticles are implanted into the surface of the cladding layer using instantaneous high-energy impact from electrical spark deposition, forming a particle-reinforced composite material layer. This composite process yields a barrier layer with extremely strong adhesion to the matrix, that is dense and tough.

[0019] In some preferred embodiments, in step (2), the slurry is mainly composed of manganese dioxide (MnO2) and doped with Co3O4 and CeO2; the microwave sintering atmosphere is an inert or reducing atmosphere, the sintering temperature is 300~600℃, and the holding time is 30~120 minutes.

[0020] Furthermore, a slurry containing manganese dioxide powder and doped oxides is uniformly coated onto the barrier layer, dried, and then sintered in a microwave sintering furnace. The overall and selective nature of microwave heating allows the active layer to rapidly and uniformly densify, reducing internal stress.

[0021] In some preferred embodiments, in step (3), a sol containing silicon source, nickel source and other modifiers is coated on the surface of the active layer, and after aging, gelation, drying and heat treatment, a dense protective film is formed.

[0022] Furthermore, the sol is prepared from tetraethyl orthosilicate, nickel nitrate, ethanol, water and a complexing agent, and is gelled and heat-treated at 350~550℃ to form a Si-Ni based composite protective layer.

[0023] The present invention also provides the application of the corrosion-resistant and long-life titanium electrode, which is used in the electrodeposition of non-ferrous metals or the electrolytic hydrogen production process under harsh electrolysis environments (such as high temperature, strong acid, and halide ion-containing environments).

[0024] Specifically, the corrosion-resistant and long-life titanium electrode exhibits excellent performance at 95℃, in a 1.0 mol / L H2SO4 solution, and at a current density of 5000 A / m²: oxygen evolution overpotential ≤1.23 V, coating bonding strength ≥48 MPa, and accelerated life >6000 hours.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] (1) Multi-layer synergistic protection: the Ti-C layer is strong and tough, the Mn-Co-Ce layer is stable and catalytic, and the Si-Ni layer is highly efficient and protective. The three layers perform their respective functions and work together to build a complete protection system from the interface to the bulk phase and then to the surface.

[0027] (2) Synergistic modification of multiple elements: Based on 2 to 3 core elements in each layer, more than 20 optional elements are introduced through open-ended methods. The interaction between elements (composite oxide formation, lattice distortion, electronic effects, etc.) is used to achieve fine control and extreme improvement of performance, breaking through the performance bottleneck of single or small amount of element modification.

[0028] (3) Process innovation and combination: The combined application of advanced processes such as laser cladding-electrospray deposition, microwave sintering, and sol-gel method ensures the compactness, uniformity and interlayer bonding of each layer structure, providing process guarantee for performance realization.

[0029] (4) Excellent overall performance: The electrode of this invention can maintain low overpotential, high binding strength and ultra-long life under harsh testing conditions, solving the problem that traditional electrodes cannot achieve all of these. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the three-layer gradient structure of the titanium electrode of the present invention (1-titanium substrate, 2-Ti-C composite barrier layer, 3-Mn-Co-Ce-based active layer, 4-Si-Ni-based composite protective layer).

[0031] Figure 2 This is a comparison graph of the tank voltage change over time in accelerated life testing of Example 1 and Comparative Example 1. Detailed Implementation

[0032] To further illustrate the content of this invention, the following description will be made more comprehensive and detailed in conjunction with preferred embodiments, but the scope of protection of this invention is not limited to the following specific embodiments.

[0033] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0034] The present invention will be further described below with reference to specific embodiments and accompanying drawings:

[0035] Example 1

[0036] 1. Ti-C composite barrier layer: After the titanium plate is pretreated, a mixture of Ti powder and graphite powder (Ti-5wt%C) is laser clad with a laser power of 2.5 kW and a scanning speed of 10 mm / s; then WC-Co nanoparticles (WC-12wt%Co) are deposited by electrical discharge machining at a voltage of 100 V for 20 min to obtain a barrier layer with a thickness of about 25 μm.

[0037] 2. Mn-Co-Ce based active layer: The slurry composition is MnO2, Co3O4, CeO2 (mass ratio 88:8:4); microwave sintering (N2 atmosphere, 550℃, 60 min) yields an active layer with a thickness of approximately 100 μm.

[0038] 3. Si-Ni based composite protective layer: The sol composition is tetraethyl orthosilicate: nickel nitrate: ethanol: water: acetylacetone = 1:0.2:10:4:0.1 (molar ratio). After heat treatment at 450℃ for 2 h, a protective layer with a thickness of about 4 μm is obtained.

[0039] When applied to non-ferrous metal electrodeposition processes, it achieves an oxygen evolution overpotential of 1.20 V, a bonding strength of 50 MPa, and an accelerated lifetime of >6000 hours.

[0040] Example 2

[0041] The Ti-C composite barrier layer is supplemented with 2% Sb; the Mn-Co-Ce-based active layer is supplemented with 1% Ag; the Si-Ni-based composite protective layer is the same as in Example 1.

[0042] When applied to non-ferrous metal electrodeposition processes, the oxygen evolution overpotential is 1.18 V, the bonding strength is 48 MPa, and the lifetime is >5800 hours.

[0043] Example 3

[0044] The Ti-C composite barrier layer is supplemented with 1% Zr and 0.5% Y; the Mn-Co-Ce-based active layer and the Si-Ni-based composite protective layer are the same as in Example 1.

[0045] When applied to non-ferrous metal electrodeposition processes, the oxygen evolution overpotential is 1.21 V, the bonding strength is 55 MPa, and the lifetime is >6100 hours.

[0046] Example 4

[0047] The Ti-C composite barrier layer is the same as in Example 1; 2% Bi2O3 is added to the Mn-Co-Ce-based active layer; 1% trifluoroacetic acid (introducing F element) is added to the Si-Ni-based composite protective layer.

[0048] When applied to the electrodeposition process of non-ferrous metals, the oxygen evolution overpotential is 1.22 V, the bonding strength is 49 MPa, and the lifetime is >5900 hours. In acidic solutions containing Cl⁻, the lifetime decay rate is significantly reduced.

[0049] Example 5

[0050] The Ti-C composite barrier layer employs a laser cladding-electro-spark deposition combined process. The laser cladding uses TiC-reinforced iron-based alloy powder with the following mass percentage composition: 60% Fe, 15% Cr, 5% Ni, with the balance being Ti and unavoidable trace impurities. Electro-spark deposition reinforcement is performed in the same manner as in Example 1. The Mn-Co-Ce-based active layer uses mixed rare earth oxides instead of CeO2, with the following mass percentage composition: 50% CeO2, 25% La2O3, and 10% Pr6O3. 11 10% Nd2O3, 5% other rare earth oxides; the Si-Ni based composite protective layer was prepared in the same way as in Example 1.

[0051] When applied to non-ferrous metal electrodeposition processes, the oxygen evolution overpotential is 1.23 V, the bonding strength is 45 MPa, the lifetime is >5700 hours, and the cost is reduced by about 15%.

[0052] Comparative Example 1

[0053] Traditional process: After micro-arc oxidation of the titanium substrate, a traditional Co-doped MnO2 coating is applied, without an outermost protective layer.

[0054] When applied to non-ferrous metal electrodeposition processes, the oxygen evolution overpotential is 1.32 V, the bonding strength is 28 MPa, and the lifetime is ~1200 hours.

[0055] Performance Testing and Comparative Analysis

[0056] Test conditions: 95℃, 1.0 mol / L H₂SO₄, 5000 A / m². Results are shown in the table below:

[0057] Sample number Oxygen evolution overpotential (V) Bond strength (MPa) Accelerate lifespan (hours) Key features Example 1 1.20 50 >6000 Excellent overall performance Example 2 1.18 48 >5800 High conductivity Example 3 1.21 55 >6100 Excellent bonding strength and toughness Example 4 1.22 49 >5900 Excellent acid resistance Example 5 1.23 45 >5700 Cost optimization Comparative Example 1 1.32 28 ~1200 Traditional process, poor performance

[0058] Performance Analysis: All embodiments significantly outperformed the comparative examples, demonstrating the substantial advantages of the three-layer structure and multi-element design of this invention. The performance differences between the various embodiments highlight the ability to customize performance by adjusting the combination of elements.

[0059] Conclusions and advantages: This invention successfully prepared a titanium electrode with ultra-high bonding strength, low oxygen evolution overpotential and ultra-long service life through innovative three-layer gradient structure design and multi-element synergistic modification. It solved the key technical bottleneck that has long plagued the development of titanium-based manganese dioxide electrodes and laid a solid foundation for their industrial application in harsh environments.

[0060] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A corrosion-resistant, long-life titanium electrode, using a titanium plate as the substrate, characterized in that, A Ti-C composite barrier layer, a Mn-Co-Ce-based active layer, and a Si-Ni-based composite protective layer are sequentially disposed on the surface of the titanium substrate from the inside to the outside, forming a three-layer gradient composite structure from the substrate to the surface.

2. The corrosion-resistant, long-life titanium electrode according to claim 1, characterized in that, The thickness of the Ti-C composite barrier layer is 10~50μm, and the composite barrier layer may also incorporate one or more of the following elements: Sn, Sb, Zr, Ir, Ta, Ru, Pt, Co, Mo, W, V, Nb, Cr, Fe, Al, Y, La, and Ce.

3. The corrosion-resistant, long-life titanium electrode according to claim 1, characterized in that, The thickness of the Mn-Co-Ce-based active layer is 50~150μm, and the active layer may also incorporate one or more of the following elements: Ni, Bi, Ag, Au, Pd, Li, Na, K, Mg, Ca, Sr, Ba, B, Ga, In, Ge, Sn, and Sb.

4. The corrosion-resistant, long-life titanium electrode according to claim 1, characterized in that, The thickness of the Si-Ni based composite protective layer is 2~10μm, and the protective layer may also incorporate one or more of the elements F, P, N, C, Al, Zn, Ti, Zr, Ce, La, Y, B, W, Mo, and V.

5. A method for preparing a corrosion-resistant, long-life titanium electrode, characterized in that, Includes the following steps: (1) Preparation of Ti-C composite barrier layer: A composite barrier layer mainly composed of Ti and C elements was formed on the surface of the titanium substrate by a combination of laser cladding and electrical discharge deposition process. (2) Preparation of Mn-Co-Ce-based active layer: A manganese dioxide-based active layer with Mn, Co, Ce and O elements as the main components is formed on the Ti-C composite barrier layer by slurry coating and microwave-assisted thermal sintering technology. (3) Preparation of Si-Ni based composite protective layer: The sol-gel method was used to form a composite protective layer mainly composed of Si, Ni and O elements on the surface of the Mn-Co-Ce based active layer.

6. The method for preparing a corrosion-resistant, long-life titanium electrode according to claim 1, characterized in that, In step (1), the alloy powder used in the laser cladding is a mixture of Ti powder and graphite powder, or Ti-C based alloy powder; the reinforcing phase powder used in the electrical discharge deposition is one or more of WC-Co, TiC, and Cr3C2.

7. The method for preparing a corrosion-resistant, long-life titanium electrode according to claim 1, characterized in that, In step (1) and step (2), the slurry is mainly composed of manganese dioxide (MnO2) and doped with Co3O4 and CeO2; the microwave sintering atmosphere is an inert or reducing atmosphere, the sintering temperature is 300~600℃, and the holding time is 30~120 minutes.

8. The method for preparing a corrosion-resistant, long-life titanium electrode according to claim 1, characterized in that, In step (3), a sol containing silicon source, nickel source and other modifiers is coated on the surface of the active layer, and after aging, gelation, drying and heat treatment, a dense protective film is formed.

9. The method for preparing a corrosion-resistant, long-life titanium electrode according to claim 8, characterized in that, In step (3), the sol is prepared from tetraethyl orthosilicate, nickel nitrate, ethanol, water and complexing agent, and is gelled and heat-treated at 350~550℃ to form a Si-Ni based composite protective layer.

10. The application of a corrosion-resistant, long-life titanium electrode according to any one of claims 1 to 4, characterized in that, It can be applied to the electrodeposition of non-ferrous metals or the electrolytic hydrogen production process under harsh electrolytic environments.

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