Inert electrode, preparation method and application thereof, and electrical equipment

Abstract

The invention provides an inert electrode and a preparation method and application thereof, and an electrical device, and relates to the technical field of conductive ceramic coating materials, the inert electrode sequentially comprises a metal matrix, a diffusion barrier layer and a titanium black layer; the diffusion barrier layer comprises carbide and / or nitride of metal M; the metal M comprises any one or a combination of at least two of titanium, zirconium, hafnium, niobium, tantalum, chromium, molybdenum, tungsten or vanadium. The titanium black coating electrode containing the diffusion barrier has the advantages of being high in treatment efficiency, low in cell pressure, long in service life, capable of being produced on a large scale and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of conductive ceramic coating materials, in particular to an inert electrode and a preparation method, application and electrical equipment thereof. BACKGROUND

[0002] Electro-catalytic oxidation technology has the advantages of strong oxidation ability, simple equipment and operation, and no secondary pollution, and is an organic wastewater treatment method with wide application prospect, especially in the treatment of refractory industrial wastewater. Electrode as the core of electrochemical oxidation technology, its catalytic activity and long-term stability are the key to determine the electrochemical oxidation ability and efficiency.

[0003] At present, the available electrode materials mainly include DSA electrode, boron-doped diamond film electrode (i.e. BDD electrode) and Magnéli phase titanium suboxide electrode. Among them, the main problems of DSA electrode are low oxygen evolution potential, poor organic matter degradation ability, a large number of cracks on the surface of the coating, and easy to fall off; although BDD electrode has the characteristics of wide potential window and corrosion resistance, its cost is high (5-7 ten thousand yuan / m 2 ), which is difficult to realize industrial application; the titanium suboxide electrode has good chemical stability and wide electrochemical stability window, and its cost is much lower than that of BDD electrode.

[0004] Therefore, Magnéli phase titanium suboxide is the most promising inert anode material.

[0005] However, the Magnéli phase titanium suboxide coating electrode prepared by the existing method is prone to overall or local peeling after a period of use or under large current density, and the reason is that the coating prepared by the existing method is obtained by sintering at high temperature, and during high-temperature sintering, the metal in the substrate and the titanium suboxide coating are prone to high-temperature interdiffusion, resulting in a large resistance at the interface between the coating and the metal substrate, which causes the interface to be oxidized to titanium dioxide first, and finally the coating peels off.

[0006] Therefore, it is of great significance to develop a titanium suboxide coating electrode with high efficiency and long service life for the development of the field. SUMMARY

[0007] In view of the deficiencies of the prior art, the purpose of the present application is to provide an inert electrode and a preparation method, application and electrical equipment thereof, which solves the problem of easy peeling of the titanium suboxide layer by setting a diffusion barrier layer between the titanium suboxide layer and the metal substrate.

[0008] To achieve this purpose, the technical solutions adopted by the present application are as follows:

[0009] In a first aspect, the present application provides an inert electrode, which comprises a metal substrate, a diffusion barrier layer and a titanium suboxide layer in sequence.

[0010] The diffusion barrier layer comprises carbide and / or nitride of metal M.

[0011] The metal M comprises any one or a combination of at least two of titanium, zirconium, hafnium, niobium, tantalum, chromium, molybdenum, tungsten or vanadium.

[0012] The conventional titanium suboxide coated inert anode is prone to problems such as interdiffusion of metal substrate elements and titanium and oxygen elements in the titanium suboxide layer during high-temperature sintering or thermal spraying, which seriously affects the service life and processing efficiency of the inert anode.

[0013] The present application adds a diffusion barrier layer between the metal substrate and the titanium suboxide layer, and the diffusion barrier layer must have good electrical conductivity, good corrosion resistance, good oxidation resistance and be able to prevent the interdiffusion of elements. The inventors have found that carbide, nitride and carbonitride of metal M can effectively solve the above technical problems.

[0014] Specifically, the metal M comprises any one or a combination of at least two of titanium, zirconium, hafnium, niobium, tantalum, chromium, molybdenum, tungsten or vanadium, and typical but non-limiting combinations are combinations of titanium and zirconium, combinations of hafnium and zirconium, combinations of titanium and hafnium, combinations of niobium and zirconium, combinations of titanium and niobium, combinations of chromium and zirconium, combinations of molybdenum and zirconium, combinations of titanium and molybdenum, combinations of tungsten and zirconium, combinations of vanadium and zirconium.

[0015] Exemplarily, the diffusion barrier layer comprises titanium carbide, titanium nitride, titanium carbonitride, zirconium carbide, hafnium carbide, niobium carbide, tantalum carbide, ditantalum carbide, chromium carbide, molybdenum carbide, tungsten carbide, any one or a combination of at least two of medium-entropy carbide ceramic, high-entropy carbide ceramic, medium-entropy nitride ceramic or high-entropy nitride ceramic composed of vanadium, niobium, tantalum, titanium, zirconium, hafnium, chromium, molybdenum and tungsten.

[0016] Preferably, the diffusion barrier layer comprises any one or a combination of at least two of medium-entropy carbide, medium-entropy nitride, high-entropy carbide or high-entropy nitride composed of metal M, and typical but non-limiting combinations are combinations of medium-entropy carbide and medium-entropy nitride, combinations of high-entropy carbide and medium-entropy nitride, combinations of medium-entropy carbide and high-entropy carbide, combinations of high-entropy nitride and high-entropy carbide, combinations of high-entropy nitride and high-entropy carbide.

[0017] The medium-entropy carbide and the medium-entropy nitride of the present application contain at least three or more metals M, the high-entropy carbide and the high-entropy nitride contain at least five or more metals M, and the ratio between each metal M element is between 0.9 and 1.1:1, for example, 0.9:1, 0.92:1, 0.95:1, 0.98:1, 0.99:1, 1.0:1, 1.02:1, 1.05:1, 1.06:1, 1.08:1, or 1.1:1, but not limited to the listed values, and other values not listed in this range are also applicable.

[0018] Furthermore, the hysteresis diffusion effect unique to the medium-entropy and high-entropy metal M carbide ceramic, nitride ceramic, and carbonitride ceramic material has a significant advantage in preventing the diffusion of metal and oxygen elements, thus effectively solving the above technical problems.

[0019] Preferably, the thickness of the diffusion barrier layer is 0.5-10 μm, for example, 0.5 μm, 1.6 μm, 2.7 μm, 3.7 μm, 4.8 μm, 5.8 μm, 6.9 μm, 7.9 μm, 9 μm, or 10 μm, but not limited to the listed values, and other values not listed in this range are also applicable.

[0020] The thickness of the diffusion barrier layer is preferably controlled in the above range. When the thickness of the diffusion barrier layer is too low, the base element cannot effectively prevent the diffusion into the titanium suboxide coating, thereby affecting the conductivity and corrosion resistance of the coating. When the thickness of the diffusion barrier layer is too high, the thermal expansion coefficient does not match, causing cracks in the coating and preventing the diffusion of the base element.

[0021] Preferably, the thickness of the titanium suboxide layer is 5-1000 μm, for example, 5 μm, 116 μm, 227 μm, 337 μm, 448 μm, 558 μm, 669 μm, 779 μm, 890 μm, or 1000 μm, but not limited to the listed values, and other values not listed in this range are also applicable.

[0022] The thickness of the titanium suboxide layer is preferably controlled in the above range. When the thickness of the titanium suboxide layer is too low, the electrochemical activity is low. When the thickness of the titanium suboxide layer is too high, the titanium suboxide coating is prone to peeling.

[0023] Preferably, the metal base includes titanium, titanium alloy, niobium, or tantalum.

[0024] Preferably, the titanium suboxide layer is a porous structure.

[0025] Preferably, the porosity of the porous structure is 10% to 60%, for example, it can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, or 60%, etc.

[0026] Preferably, the pore size of the porous structure ranges from 1 to 50 μm, for example, it can be 1 μm, 2 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 40 μm, or 50 μm, etc.

[0027] In a second aspect, the present application provides a preparation method of the inert electrode of the first aspect, the preparation method comprising the following steps:

[0028] (1) forming a diffusion barrier layer on the surface of the metal substrate to obtain a first substrate.

[0029] (2) forming a titanium suboxide layer on the surface of the first substrate to obtain a second substrate.

[0030] (3) sintering and cooling the second substrate to obtain the inert electrode.

[0031] Preferably, the step of forming a diffusion barrier layer in step (1) comprises: depositing a diffusion barrier layer on the surface of the metal substrate by physical vapor deposition, chemical vapor deposition, or molten salt electrophoretic deposition.

[0032] The present application does not have special limitations on the deposition process of the specific diffusion barrier layer, and the deposition method known to those skilled in the art can be used.

[0033] Preferably, the step of forming a titanium suboxide layer in step (2) comprises: covering a titanium suboxide-containing slurry on the surface of the diffusion barrier layer of the first substrate and drying.

[0034] Preferably, the titanium suboxide-containing slurry in step (2) comprises titanium suboxide powder, a binder, and a solvent.

[0035] Preferably, the mass percentage of titanium suboxide powder in the titanium suboxide-containing slurry is 5 to 60 wt%, for example, it can be 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, or 60 wt%, etc.

[0036] Preferably, the binder comprises sodium water glass and / or potassium water glass.

[0037] Preferably, the solvent comprises water and / or ethanol.

[0038] Preferably, the particle size of the titanium suboxide powder is <1 μm, such as 0.9 μm, 0.89 μm, 0.85 μm, 0.8 μm, 0.78 μm, 0.75 μm, 0.7 μm, 0.65 μm, or 0.6 μm, etc., but not limited to the listed values, other unlisted values within the range are also applicable.

[0039] Preferably, the titanium suboxide powder comprises any one of Ti3O5, Ti4O7, Ti5O9, Ti6O 11 , Ti7O 13 , Ti8O 15 , Ti9O 17 or Ti 10 O 19 , or a combination of at least two thereof, wherein typical but non-limiting combinations are the combination of Ti3O5and Ti4O7, the combination of Ti5O9and Ti4O7, the combination of Ti3O5and Ti5O9, the combination of Ti6O 11 and Ti4O7, the combination of Ti3O5and Ti6O 11 , the combination of Ti7O 13 and Ti4O7, the combination of Ti3O5and Ti7O 13 , the combination of Ti9O 17 and Ti7O 13 , the combination of Ti8O 15 and Ti 10 O 19 .

[0040] Preferably, the preparation of the titanium suboxide-containing slurry comprises mixing the titanium suboxide powder, the binder and the solvent, and ball milling to obtain the titanium suboxide-containing slurry.

[0041] Preferably, the rotation speed of the ball milling is 400-1000 rpm, such as 400 rpm, 500 rpm, 550 rpm, 600 rpm, 650 rpm, 700 rpm, 750 rpm, 800 rpm, 850 rpm, 900 rpm, 950 rpm, or 1000 rpm, etc.

[0042] Preferably, the ball-to-material ratio of the ball milling is 2:1-10:1, such as 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, or 10:1, etc.

[0043] Preferably, the ball milling time is 1-24 h, such as 1 h, 2 h, 3 h, 4 h, 5 h, 8 h, 10 h, 12 h, 15 h, 18 h, 20 h, 22 h, or 24 h, etc.

[0044] Preferably, the sintering atmosphere in step (3) comprises a vacuum atmosphere or a protective atmosphere.

[0045] Preferably, the protective atmosphere comprises any one or a combination of at least two of an argon atmosphere, a nitrogen atmosphere, a helium atmosphere or a hydrogen atmosphere, wherein typical but non-limiting combinations are a combination of an argon atmosphere and a nitrogen atmosphere, a combination of a helium atmosphere and a nitrogen atmosphere, a combination of an argon atmosphere and a helium atmosphere, and a combination of a hydrogen atmosphere and a nitrogen atmosphere.

[0046] Preferably, the sintering temperature is 800-1200℃, for example, it can be 800℃, 845℃, 880℃, 930℃, 970℃, 1020℃, 1060℃, 1110℃, 1150℃ or 1200℃, etc., but is not limited to the listed values, and other unlisted values within the range are also applicable.

[0047] Preferably, the holding time of the sintering is 10 min-3 h, for example, it can be 10 min, 20 min, 30 min, 40 min, 50 min, 1 h, 1.2 h, 1.5 h, 1.8 h, 2 h, 2.2 h, 2.5 h, 2.8 h or 3 h, etc., but is not limited to the listed values, and other unlisted values within the range are also applicable.

[0048] As a preferred technical solution of the present application, the preparation method comprises the following steps:

[0049] (1) forming a diffusion barrier layer on the surface of a metal substrate to obtain a first substrate; specifically, the step of forming the diffusion barrier layer comprises depositing a diffusion barrier layer on the surface of a metal substrate by physical vapor deposition, chemical vapor deposition or molten salt electrophoretic deposition.

[0050] (2) mixing titanium suboxide powder with a particle size <1 μm, a binder and a solvent, and ball milling under the conditions of a rotation speed of 400-1000 rpm and a ball-to-material ratio of 2:1-10:1 for 1-24 h to obtain a titanium suboxide-containing slurry; wherein the mass percentage of the titanium suboxide powder in the titanium suboxide-containing slurry is 5-60 wt%, the titanium suboxide-containing slurry is coated on the surface of the diffusion barrier layer of the first substrate and dried to form a titanium suboxide layer on the surface of the first substrate, thereby obtaining a second substrate.

[0051] (3) sintering the second substrate at 800-1200℃ in a vacuum atmosphere or a protective atmosphere for 10 min-2 h and cooling to obtain the inert electrode.

[0052] The drying in the above process is not particularly limited, and any device and mode known to those skilled in the art that can be used for drying can be used, and adjustment can be made according to the actual process, for example, air drying, vacuum drying, drying or freeze drying, or a combination of different modes.

[0053] In a third aspect, the present application provides application of the inert electrode of the first aspect in organic wastewater treatment, electrochemical metallurgy, electroplating, electrolytic water, chlor-alkali industry or molten salt electrolysis industry.

[0054] The high-performance inert electrode with diffusion barrier prepared by the present application can be used as an inert anode in organic wastewater treatment, electrochemical metallurgy, electroplating, electrolytic water, chlor-alkali industry and molten salt electrolysis, and can also be used as an inert anode in electrical equipment, and has the advantages of high treatment efficiency and long service life.

[0055] In a fourth aspect, the present application provides an electrical equipment comprising an inert electrode, wherein the inert electrode comprises the inert electrode of the first aspect.

[0056] Compared with the prior art, the present application has at least the following beneficial effects:

[0057] (1) The inert electrode provided by the present application can effectively solve the problems of high cell voltage, low treatment efficiency, coating peeling and short service life of the existing titanium sub-oxide coated electrode due to the large resistance at the interface between the coating and the substrate, and the service life of the inert electrode is more than 3800 min.

[0058] (2) When the inert electrode provided by the present application is used in organic wastewater treatment, electrochemical metallurgy, electroplating, electrolytic water, chlor-alkali industry and molten salt electrolysis, it has the advantages of high treatment efficiency, low cell voltage and long service life. BRIEF DESCRIPTION OF DRAWINGS

[0059] Figure 1 The structure of the inert electrode provided by Example 4 of the present application is shown in the schematic diagram.

[0060] Figure 2 The XRD spectrum of the inert electrode obtained from Example 4 is shown.

[0061] Figure 3 The cross-sectional SEM spectrum of the inert electrode obtained from Example 4 is shown.

[0062] In the figure: 1, metal substrate; 2, diffusion barrier layer; 3, titanium sub-oxide layer. DETAILED DESCRIPTION

[0063] In order to facilitate understanding of the present application, the present application is illustrated by the following examples. Those skilled in the art should understand that the examples are only used to help understand the present application, and should not be regarded as a specific limitation on the present application.

[0064] It should be understood that, in the description of the present application, the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0065] It should be noted that, in the description of the present application, unless otherwise specified and limited, the terms "provided", "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0066] Embodiment 1

[0067] The present embodiment provides an inert electrode, which comprises a metal substrate, a diffusion barrier layer and a titanium suboxide layer in sequence.

[0068] The metal substrate is a titanium metal plate, and the thickness of the metal substrate is 2 mm.

[0069] The diffusion barrier layer is a (TiZrNbTaHf)C high-entropy ceramic diffusion barrier layer, and the thickness of the diffusion barrier layer is 5 μm.

[0070] The thickness of the titanium suboxide layer is 100 μm, the titanium suboxide layer is a porous structure, the porosity of the porous structure is 46.5%, and the pore size range of the porous structure is 6-18 μm.

[0071] The present embodiment also provides a preparation method of the inert electrode, which comprises the following steps:

[0072] (1) forming a diffusion barrier layer on the surface of the metal substrate to obtain a first substrate; specifically, the step of forming the diffusion barrier layer comprises: depositing a (TiZrNbTaHf)C high-entropy ceramic diffusion barrier layer on the surface of the titanium metal plate by physical vapor deposition.

[0073] (2) mixing titanium suboxide powder with a particle size of less than 1 μm, potassium water glass and water, and ball milling under the conditions of a rotation speed of 600 rpm and a ball-to-material ratio of 8:1 for 20 h to obtain a titanium suboxide-containing slurry; wherein the mass percentage of the titanium suboxide powder (Ti4O7) in the titanium suboxide-containing slurry is 30 wt%, the titanium suboxide-containing slurry is coated on the surface of the diffusion barrier layer of the first substrate multiple times until a target thickness is reached, and then dried to form a titanium suboxide layer on the surface of the first substrate to obtain a second substrate.

[0074] (3) placing the second substrate in a sintering furnace and sintering at 900℃ in a vacuum atmosphere for 1 h, and then cooling to room temperature to obtain the inert electrode.

[0075] Embodiment 2

[0076] The embodiment provides an inert electrode, which comprises a metal substrate, a diffusion barrier layer and a titanium suboxide layer in sequence.

[0077] The metal substrate is a TC4 titanium alloy plate, and the thickness of the metal substrate is 1.5 mm.

[0078] The diffusion barrier layer is a (TiZrNbMoW)C high-entropy ceramic diffusion barrier layer, and the thickness of the diffusion barrier layer is 3 μm.

[0079] The thickness of the titanium suboxide layer is 75 μm, the titanium suboxide layer has a porous structure, the porosity of the porous structure is 35%, and the pore size of the porous structure ranges from 5 μm to 20 μm.

[0080] The embodiment further provides a preparation method of the inert electrode, which comprises the following steps:

[0081] (1) forming a diffusion barrier layer on the surface of the metal substrate to obtain a first substrate; specifically, the step of forming the diffusion barrier layer comprises: depositing a (TiZrNbMoW)C high-entropy ceramic diffusion barrier layer on the surface of the TC4 plate by physical vapor deposition.

[0082] (2) mixing titanium suboxide powder with particle size <1 μm, sodium water glass and ethanol, and ball milling under the condition of 850 rpm and ball-to-material ratio of 5:1 for 12 h to obtain a titanium suboxide-containing slurry; wherein the mass percentage of titanium suboxide powder (Ti4O7 and Ti5O9, mass ratio of 1:1) in the titanium suboxide-containing slurry is 26 wt%, the titanium suboxide-containing slurry is coated on the surface of the diffusion barrier layer of the first substrate multiple times until the target thickness, and dried to form a titanium suboxide layer on the surface of the first substrate, thereby obtaining a second substrate.

[0083] (3) the second substrate is placed in a sintering furnace and sintered at 1100℃ for 10 min in an atmosphere of hydrogen and argon (volume ratio of argon to hydrogen is 1:1), and then cooled to room temperature to obtain the inert electrode.

[0084] Example 3

[0085] The inert electrode provided in the present example comprises a metal substrate, a diffusion barrier layer and a titanium suboxide layer in sequence.

[0086] The metal substrate is a titanium metal plate, and the thickness of the metal substrate is 3 mm.

[0087] The diffusion barrier layer is a (TiZrNbTa)N entropy ceramic diffusion barrier layer, and the thickness of the diffusion barrier layer is 10 μm.

[0088] The thickness of the titanium suboxide layer is 500 μm, the titanium suboxide layer has a porous structure, the porosity of the porous structure is 22%, and the pore size of the porous structure ranges from 15 to 38 μm.

[0089] The present example also provides a preparation method of the inert electrode, which comprises the following steps:

[0090] (1) forming a diffusion barrier layer on the surface of the metal substrate to obtain a first substrate; specifically, the step of forming the diffusion barrier layer comprises depositing a (TiZrNbTa)N entropy ceramic diffusion barrier layer on the surface of the titanium metal plate by chemical vapor deposition.

[0091] (2) mixing titanium suboxide powder with particle size <1 μm, potassium water glass and water, and ball milling under the condition of 550 rpm and ball-to-material ratio of 4:1 for 18 h to obtain a titanium suboxide-containing slurry; wherein the mass percentage of titanium suboxide powder (Ti4O7) in the titanium suboxide-containing slurry is 18 wt%, the titanium suboxide-containing slurry is coated on the surface of the diffusion barrier layer of the first substrate multiple times until the target thickness, and dried to form a titanium suboxide layer on the surface of the first substrate, thereby obtaining a second substrate.

[0092] (3) The second substrate is placed in a sintering furnace and sintered at 900℃ for 3h in a nitrogen atmosphere, and then cooled to room temperature to obtain the inert electrode.

[0093] Example 4

[0094] The inert electrode provided in this example comprises a metal substrate 1, a diffusion barrier layer 2 and a titanium suboxide layer 3 in sequence.

[0095] The metal substrate 1 is a titanium metal plate, and the thickness of the metal substrate 1 is 1mm.

[0096] The diffusion barrier layer 2 is a titanium carbide diffusion barrier layer, and the thickness of the diffusion barrier layer 2 is 2μm.

[0097] The thickness of the titanium suboxide layer 3 is 8μm, the titanium suboxide layer 3 is a porous structure, the porosity of the porous structure is 16%, and the pore size of the porous structure ranges from 2μm to 12μm.

[0098] The preparation method of the inert electrode provided in this example comprises the following steps:

[0099] (1) Forming a diffusion barrier layer on the surface of a metal substrate to obtain a first substrate; specifically, the step of forming a diffusion barrier layer comprises: depositing a titanium carbide diffusion barrier layer on the surface of a titanium metal plate by using a molten salt electrophoretic deposition method.

[0100] (2) Mixing titanium suboxide powder with a particle size of <1μm, sodium water glass and water, and ball milling under the conditions of a rotation speed of 800rpm and a ball-to-material ratio of 3:1 for 6h to obtain a titanium suboxide-containing slurry; wherein the mass percentage content of titanium suboxide powder (Ti4O7) in the titanium suboxide-containing slurry is 45wt%, the titanium suboxide-containing slurry is coated on the surface of the diffusion barrier layer of the first substrate multiple times until the target thickness, and dried to form a titanium suboxide layer on the surface of the first substrate to obtain a second substrate.

[0101] (3) The second substrate is placed in a sintering furnace and sintered at 1000℃ for 30min in an argon atmosphere, and then cooled to room temperature to obtain the inert electrode.

[0102] The inert electrode obtained in this example is characterized by XRD, and the results are shown in Figure 2 All the diffraction peaks in the figure correspond to the standard diffraction peaks of Ti4O7, indicating that the titanium suboxide coating is composed of single-phase Ti4O7. The cross-sectional SEM results are shown in Figure 3 It can be seen that the titanium carbide diffusion barrier layer is dense and defect-free, and the Ti4O7 coating layer is a porous structure.

[0103] Example 5

[0104] The present example provides an inert electrode which is the same as that of Example 1 except that (TiZrNbTaHf)C is replaced by a titanium carbide diffusion barrier layer of the same thickness, and which is not described here again.

[0105] Example 6

[0106] The present example provides an inert electrode which is the same as that of Example 1 except that (TiZrNbTaHf)C is replaced by a niobium nitride diffusion barrier layer of the same thickness, and which is not described here again.

[0107] Example 7

[0108] The present example provides an inert electrode which is the same as that of Example 1 except that the thickness of the diffusion barrier layer is 0.1 μm, and which is not described here again.

[0109] Example 8

[0110] The present example provides an inert electrode which is the same as that of Example 1 except that the thickness of the diffusion barrier layer is 15 μm, and which is not described here again.

[0111] Example 9

[0112] The present example provides an inert electrode which is the same as that of Example 1 except that the thickness of the titanium suboxide layer is 3 μm, and which is not described here again.

[0113] Comparative Example 1

[0114] The present comparative example provides an inert electrode which is the same as that of Example 1 except that no diffusion barrier layer is provided, i.e. step (1) is not performed in the preparation method, and a titanium suboxide layer is formed directly on the surface of the metal substrate, and which is not described here again.

[0115] Comparative Example 2

[0116] The present comparative example provides an inert electrode which is the same as that of Example 4 except that no diffusion barrier layer is provided, i.e. step (1) is not performed in the preparation method, and a titanium suboxide layer is formed directly on the surface of the metal substrate, and which is not described here again.

[0117] In order to verify the beneficial effects of the present application, the following test scheme is designed for verification.

[0118] Degradation effect on COD of methyl orange-containing wastewater: The electrodes obtained in the above examples and comparative examples are used as anodes, and a stainless steel plate is used as a cathode to treat methyl orange-containing wastewater with an initial COD of 825 mg / L. The current density is 20 mA / cm 2 , and the COD of the wastewater is measured after the same treatment time, and the results are shown in Table 1.

[0119] Table 1

[0120] COD of raw water / mg / L COD after treatment / mg / L COD removal rate / % Example 1 825 16 98.1 Example 2 825 47 94.3 Example 3 825 22 97.3 Example 4 825 86 89.6 Example 5 825 58 92.9 Example 6 825 76 90.8 Example 7 825 366 55.6 Example 8 825 132 84.0 Example 9 825 734 11.0 Comparative Example 1 825 182 77.9 Comparative Example 2 825 268 67.5

[0121] As can be seen from Table 1: comprehensive examples 1-3 can be seen that the titanium sub-oxide electrode containing diffusion barrier obtained by the present application is used for anode treatment of methyl orange wastewater, and the treatment effect is obviously better than that of the titanium sub-oxide coating electrode without diffusion barrier shown in Comparative Example 1 and Comparative Example 2. It can be seen that the presence of diffusion barrier has a synergistic effect on improving the degradation of COD of titanium sub-oxide electrode.

[0122] As can be seen from Comparative Example 1 and Examples 5-6, it is preferred to use middle-entropy carbide, middle-entropy nitride, high-entropy carbide or high-entropy nitride composed of metal M as the diffusion barrier layer, which can further improve the treatment effect of COD.

[0123] As can be seen from Comparative Example 1 and Examples 7-8, in Example 7, the thickness of the diffusion barrier layer is 0.1 μm, which is easy to cause the titanium element in the substrate to diffuse into the titanium sub-oxide during the sintering of the titanium sub-oxide coating, and reduce the titanium sub-oxide such as Ti4O7 to Ti3O5 at high temperature, thereby causing the conductivity of the titanium sub-oxide coating to decrease and the electrocatalytic activity to decrease. In Example 8, the thickness of the diffusion barrier layer is 15 μm, which is easy to form cracks between the titanium sub-oxide coating and the diffusion barrier layer due to the difference in the thermal expansion coefficient of the titanium sub-oxide and the diffusion barrier layer during the cooling process of sintering the titanium sub-oxide coating at high temperature, thereby causing the service life of the electrode to decrease seriously.

[0124] As can be seen from Comparative Example 1 and Example 9, when the thickness of the titanium sub-oxide is 3 μm, the surface active site of the electrode is less, which causes the degradation efficiency of the organic wastewater to be low, and the electrode cannot work at a large current density.

[0125] Electrode service life test

[0126] The electrodes obtained in the above examples and comparative examples are used as anodes, and the stainless steel plates are used as cathodes, wherein: the electrolyte is a 1M sulfuric acid solution, the current density is 2 A / cm 2 , the electrode spacing is 1 cm, the sudden rise of the cell voltage to 10V is taken as the electrode failure time, the electrode service life is recorded, and the results are shown in Table 2.

[0127] Table 2

[0128]

[0129]

[0130] As shown in Table 2, the inert anode electrode with the diffusion barrier-containing sub-titanium oxide coating obtained by the application has a much longer service life than the electrode without the diffusion barrier-containing sub-titanium oxide coating, which indicates that the diffusion barrier layer plays an important role in improving the service life of the sub-titanium oxide electrode.

[0131] In Example 9, the sub-titanium oxide has a low thickness, and the electrode surface has a small number of active sites, which leads to a low degradation efficiency of organic wastewater, and the electrode is difficult to work at a large current density and has a short service life.

[0132] The above examples are used to illustrate the detailed features of the application, but the application is not limited to the above detailed features, i.e., it does not mean that the application must rely on the above detailed features to be implemented. It should be understood by those skilled in the art that any improvement of the application, equivalent replacement of the selected technical features of the application, addition of auxiliary technical features, selection of specific modes, etc. fall within the protection scope and disclosure scope of the application.

Claims

1. An inert electrode, characterized in that, The inert electrode comprises, in sequence, a metal substrate, a diffusion barrier layer, and a sub-titanium oxide layer; The diffusion barrier layer comprises carbides and / or nitrides of metal M; The metal M includes any one or a combination of at least two of the following: titanium, zirconium, hafnium, niobium, tantalum, chromium, molybdenum, tungsten, or vanadium.

2. The inert electrode according to claim 1, characterized in that, The diffusion barrier layer comprises any one or a combination of at least two of the following: a medium-entropy carbide, a medium-entropy nitride, a high-entropy carbide, or a high-entropy nitride composed of metal M.

3. The inert electrode according to claim 1 or 2, characterized in that, The thickness of the diffusion barrier layer is 0.5–10 μm; Preferably, the thickness of the sub-titanium oxide layer is 5–1000 μm; Preferably, the metal matrix includes titanium, titanium alloy, niobium, or tantalum.

4. A method for preparing an inert electrode according to any one of claims 1 to 3, characterized in that, The preparation method includes the following steps: (1) A diffusion barrier layer is formed on the surface of a metal substrate to obtain a first substrate; (2) A sub-titanium oxide layer is formed on the surface of the first substrate to obtain a second substrate; (3) The second substrate is sintered and cooled to obtain the inert electrode.

5. The preparation method according to claim 4, characterized in that, The step of forming a diffusion barrier layer in step (1) includes depositing a diffusion barrier layer on the surface of a metal substrate using physical vapor deposition, chemical vapor deposition, or molten salt electrophoretic deposition.

6. The preparation method according to claim 4 or 5, characterized in that, The step of forming the sub-titanium oxide layer in step (2) includes: covering the diffusion barrier layer surface of the first substrate with a sub-titanium oxide slurry and drying it; Preferably, the titanium suboxide-containing slurry in step (2) includes titanium suboxide powder, binder and solvent; Preferably, the titanium suboxide powder content in the titanium suboxide-containing slurry is 5-60 wt%. Preferably, the binder comprises sodium silicate and / or potassium silicate; Preferably, the solvent includes water and / or ethanol; Preferably, the particle size of the sub-titanium oxide powder is <1 μm; Preferably, the sub-titanium oxide powder comprises Ti3O5, Ti4O7, Ti5O9, and Ti6O. 11 Ti7O 13 Ti8O 15 Ti9O 17 or Ti 10 O 19 Any one or at least two of them.

7. The preparation method according to claim 6, characterized in that, The preparation of the titanium suboxide-containing slurry includes: mixing titanium suboxide powder, binder and solvent, and ball milling to obtain the titanium suboxide-containing slurry.

8. The preparation method according to claim 7, characterized in that, The sintering atmosphere described in step (3) includes a vacuum atmosphere or a protective atmosphere; Preferably, the protective atmosphere includes any one or a combination of at least two of the following: argon atmosphere, nitrogen atmosphere, helium atmosphere, or hydrogen atmosphere; Preferably, the sintering temperature is 800–1200°C; Preferably, the holding time for sintering is 10 min to 3 h.

9. The application of an inert electrode according to any one of claims 1 to 3 in organic wastewater treatment, electrochemical metallurgy, electroplating, water electrolysis, chlor-alkali industry or molten salt electrolysis industry.

10. An electrical-related device, the electrical-related device comprising an inert electrode, characterized in that, The inert electrode includes the inert electrode as described in any one of claims 1 to 3.

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