A composite electrode and a method for preparing the same

Abstract

The present invention provides a composite electrode and a preparation method thereof, wherein the composite electrode comprises a substrate, a metal layer, an insulating layer, a grid electrode and a three-dimensional nanoporous micro-pillar array electrode; a grid-shaped groove is provided on the surface of the substrate, so that a plurality of protrusions are formed on the surface of the substrate; a metal layer and an insulating layer are sequentially arranged on the undulating substrate surface; a grid electrode is arranged on the side away from the metal layer in the portion of the insulating layer located in the grid-shaped groove, and a mesh of the grid electrode is formed in the portion located in the protrusion; the mesh is provided with 0, 1 or more nanoporous micro-pillar electrodes; the nanoporous micro-pillar electrode has a nanoporous structure, and each nanoporous micro-pillar electrode penetrates the insulating layer and extends to the side of the metal layer facing the substrate. The three-dimensional nanoporous micro-pillar array electrode is tightly surrounded by the grid electrode, and the whole is similar to an interdigitated micro-electrode array. The composite electrode has the advantages of both the interdigitated micro-electrode array and the three-dimensional micro-electrode array; and has a higher specific surface area and better electrochemical performance.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochemistry, and in particular relates to a composite electrode and a preparation method thereof. Background Art

[0002] Microelectrodes refer to a type of electrode that is micrometer-sized in at least one dimension, such as microdisk electrodes and microstrip electrodes. Compared with conventional electrodes, microelectrodes have many excellent electrochemical properties, such as small charging current, high signal-to-noise ratio, small iR drop, high mass transfer rate, short response time and high sensitivity. The microelectrode array is composed of multiple microelectrodes in an array form, with a small overall size and high integration. While inheriting many excellent electrochemical properties of a single microelectrode, the microelectrode array also obtains a larger current intensity and better output signal, effectively making up for the shortcomings of a single microelectrode, such as low current signal and susceptibility to environmental interference.

[0003] The interdigitated microelectrode array generally refers to a composite electrode formed by the cross combination of two finger-shaped or comb-shaped planar microelectrode arrays. In the interdigitated microelectrode array, the two sides of the finger electrodes of any planar microelectrode array are closely adjacent to the finger electrodes of the other planar microelectrode array. The structure of the interdigitated microelectrode array can be adjusted by controlling the spacing, width, length, height, number and other parameters of the finger electrodes. Since the interdigitated microelectrode array is a two-in-one planar composite electrode, it can detect from a single side of the sample, is suitable for use as a non-destructive testing sensor, and is conducive to reducing the amount of sample used.

[0004] However, the interdigitated microelectrode array is usually based on a planar microelectrode array, which has certain limitations in electrochemical performance compared to a three-dimensional microelectrode array. Therefore, the interdigitated microelectrode array in the related art cannot meet the diverse application requirements.

[0005] In addition, the preparation method of microelectrode arrays usually uses photolithography or nanoimprinting technology to transfer specific geometric patterns to the substrate, and then combines processing processes such as etching and metal deposition. This type of preparation method has the advantages of strong designability, mature technology, and easy large-scale production, but it also has obvious disadvantages such as expensive equipment, complicated preparation process, and high production cost. Summary of the invention

[0006] The technical purpose of the present invention is to provide a three-dimensional nanoporous micropillar array-grid composite electrode and a preparation method thereof, aiming to solve the technical problems that the related technical interdigitated microelectrode array cannot meet the diverse application requirements and the preparation of the microelectrode array has the disadvantages of expensive equipment, complicated preparation process and high production cost.

[0007] To solve the above technical problems, the present invention is implemented in this way.

[0008] The first aspect of the present invention provides a composite electrode, which includes a substrate 1, a metal layer 2, an insulating layer 3, a grid electrode 7 and a three-dimensional nanoporous micro-pillar array electrode 6; the surface of the substrate 1 is provided with a grid-like groove, so that a plurality of protrusions are formed on the surface of the substrate 1, and these protrusions are separated from each other and arranged in an array; the metal layer 2 is arranged on the uneven surface of the substrate 1, and the insulating layer 3 is arranged on the side of the metal layer 2 away from the substrate 1; the part of the insulating layer 3 located in the grid-like groove is provided with a grid electrode 7 on the side away from the metal layer 2, and the part of the insulating layer 3 located in the protrusion forms the mesh of the grid electrode 7; the nanoporous micro-pillar electrode in which the three-dimensional nanoporous micro-pillar array electrode 6 is arranged in all or part of the mesh, and the mesh is provided with a plurality of protrusions; In the case where nanoporous micro-pillar electrodes are provided, one or more nanoporous micro-pillar electrodes are provided in such meshes; the nanoporous micro-pillar electrodes have a nanoporous structure 60, and each nanoporous micro-pillar electrode penetrates the insulating layer 3 and extends to connect to the side of the metal layer 2 facing the substrate 1; the material of the substrate 1 is at least one of ceramic, sapphire glass, quartz glass, borosilicate glass or aluminosilicate glass; the material of the metal layer 2 is at least one of gold, platinum, silver, palladium, copper, bismuth or titanium; the material of the insulating layer 3 is at least one of silicon dioxide, silicon nitride or a non-conductive polymer; the material of the three-dimensional nanoporous micro-pillar array electrode 6 includes the material of the metal layer 2; the material of the grid electrode 7 is a metal with higher activity than the material of the metal layer 2.

[0009] Furthermore, the grid electrodes 7 are interconnected as a whole.

[0010] Furthermore, the diameter of the mesh is 100nm-1mm.

[0011] Furthermore, the nanoporous micro-column electrode has a diameter of 50 nm to 500 μm and a length of 100 nm to 1 mm.

[0012] The second aspect of the present invention provides a method for preparing a composite electrode, the method comprising: step 1, processing a grid-like groove on the surface of a substrate 1 to form a plurality of protrusions on the surface of the substrate 1, wherein the protrusions are separated from each other and arranged in an array; step 2, sequentially depositing a metal layer 2, an insulating layer 3 and a sacrificial layer 4 on the substrate 1 processed in step 1; step 3, heating one or more local micro-regions of the deposited layered structure of all or part of the protrusions along the direction of the sacrificial layer 4 toward the insulating layer 3 and the metal layer 2 or along the direction of the metal layer 2 toward the insulating layer 3 and the sacrificial layer 4, to form a plurality of columnar metal molten regions with the metal layer 2 and the sacrificial layer 4 connected at both ends and the insulating layer 3 penetrating in the middle, and heating the columnar metal molten regions; The molten metal area is cooled and solidified to form alloy microcolumns, and all the alloy microcolumns together constitute a three-dimensional alloy microcolumn array 5; step 4, according to the electrochemical dealloying method, a three-electrode system is used to dissolve the material of the sacrificial layer 4 on the protruding portion of the substrate 1, but the sacrificial layer 4 on the grid-shaped groove of the substrate 1 is retained, so that the sacrificial layer 4 is transformed into a grid electrode 7, and at the same time, the material of the sacrificial layer 4 in each alloy microcolumn is dissolved, so that a nanoporous structure 60 is generated in the microcolumn, and the alloy microcolumns are transformed into nanoporous microcolumns, and all the nanoporous microcolumns together constitute a three-dimensional nanoporous microcolumn array electrode 6, thereby obtaining a three-dimensional nanoporous microcolumn array-grid composite electrode; the material of the sacrificial layer 4 is the material of the grid electrode 7.

[0013] Furthermore, the surface processing of the substrate 1 in step 1 adopts at least one method selected from the group consisting of laser etching, plasma etching, chemical etching, mechanical engraving or embossing.

[0014] Furthermore, in step 1, the cross-sectional shape of the grid-shaped grooves of the substrate 1 is at least one of a V-shape, a U-shape, an arc shape, a rectangle or a trapezoid.

[0015] Furthermore, in step 2, the deposition method used is at least one of physical vapor deposition, chemical vapor deposition, electrochemical deposition, hot dipping, spraying, spin coating, dip coating or screen printing.

[0016] Furthermore, in step 3, micro-area heating is performed by using a laser heating method or an electron beam heating method.

[0017] Furthermore, the electrochemical dealloying method used in step 4 is a constant potential electrochemical dealloying method.

[0018] Compared with the related art, the composite electrode and the preparation method thereof in the present invention have the following beneficial effects:

[0019] The composite electrode of the present invention includes a grid electrode and a three-dimensional nanoporous micro-pillar array electrode, wherein the nanoporous micro-pillar electrode of the three-dimensional nanoporous micro-pillar array electrode is arranged in the mesh of the grid electrode, that is, the three-dimensional nanoporous micro-pillar array electrode is tightly surrounded by the grid electrode, so that the composite electrode as a whole can be similar to an interdigitated micro-electrode array. In actual use, the composite electrode can adopt a two-electrode mode or a three-electrode mode (one of the grid electrode and the three-dimensional nanoporous micro-pillar array electrode is a working electrode, and the other is a counter electrode) to measure the impedance, capacitance and conductivity of the sample; it can also adopt a four-electrode mode (the grid electrode and the three-dimensional nanoporous micro-pillar array electrode are both independent working electrodes) to simultaneously control different electrochemical reactions, and can realize redox cycling and in-situ pH value control.

[0020] Furthermore, the grid electrodes and the three-dimensional nanoporous microcolumn array electrodes are distributed in three-dimensional space. Compared with the interdigitated microelectrode array, the composite electrode of the embodiment of the present invention can have a higher specific surface area, further reduce the electrode impedance and improve the signal-to-noise ratio, so that the composite electrode has better detection sensitivity, and has many advantages of the interdigitated microelectrode array and the three-dimensional microelectrode array, and can be applied to environmental testing, food safety, medical and other fields.

[0021] In addition, the two electrodes of the composite electrode are two different electrodes, namely a grid electrode and a three-dimensional nanoporous microcolumn array electrode, which are different from the two electrodes in the interdigitated microelectrode array which are the same electrodes. Therefore, the embodiments of the present invention are conducive to enriching the structure of the microelectrode array, improving the detection performance, and expanding the application field. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 Schematic diagram of the process of preparing a composite electrode in an embodiment of the present invention;

[0024] Figure 2 It is a schematic diagram of the process of step 2 in the embodiment of the present invention.

[0025] In the accompanying drawings, each reference numeral represents: 1, substrate; 2, metal layer; 3, insulating layer; 4, sacrificial layer; 5, three-dimensional alloy micro-pillar array; 6, three-dimensional nanoporous micro-pillar array electrode; 7, grid electrode; 60, nanoporous structure. DETAILED DESCRIPTION

[0026] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but are not to be construed as limiting the present invention. All other embodiments obtained by ordinary technicians in the field without creative work based on the embodiments of the present invention are within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "circumferential", "radial" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0028] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0029] See also Figure 1-2In a first aspect, an embodiment of the present invention provides a composite electrode, which comprises a substrate 1, a metal layer 2, an insulating layer 3, a grid electrode 7 and a three-dimensional nanoporous micro-pillar array electrode 6; a grid-shaped groove is provided on the surface of the substrate 1, so that a plurality of protrusions are formed on the surface of the substrate 1, and these protrusions are separated from each other and arranged in an array; the metal layer 2 is arranged on the uneven surface of the substrate 1, and the insulating layer 3 is arranged on the side of the metal layer 2 away from the substrate 1; the part of the insulating layer 3 located in the grid-shaped groove is provided with a grid electrode 7 on the side away from the metal layer 2, and the part of the insulating layer 3 located in the protrusion forms the mesh of the grid electrode 7; a nanoporous micro-pillar electrode having a three-dimensional nanoporous micro-pillar array electrode 6 arranged in all or part of the meshes, and the meshes are provided with a plurality of protrusions; In the case where nanoporous micro-pillar electrodes are provided, one or more nanoporous micro-pillar electrodes are provided in such meshes; the nanoporous micro-pillar electrodes have a nanoporous structure 60, and each nanoporous micro-pillar electrode penetrates the insulating layer 3 and extends to connect to the side of the metal layer 2 facing the substrate 1; the material of the substrate 1 is at least one of ceramic, sapphire glass, quartz glass, borosilicate glass or aluminosilicate glass; the material of the metal layer 2 is at least one of gold, platinum, silver, palladium, copper, bismuth or titanium; the material of the insulating layer 3 is at least one of silicon dioxide, silicon nitride or a non-conductive polymer; the material of the three-dimensional nanoporous micro-pillar array electrode 6 includes the material of the metal layer 2; the material of the grid electrode 7 is a metal with higher activity than the material of the metal layer 2.

[0030] The composite electrode of the embodiment of the present invention includes a grid electrode 7 and a three-dimensional nanoporous micro-pillar array electrode 6, wherein the nanoporous micro-pillar electrodes of the three-dimensional nanoporous micro-pillar array electrode 6 are arranged in the mesh of the grid electrode 7, that is, the three-dimensional nanoporous micro-pillar array electrode 6 is tightly surrounded by the grid electrode 7, so that the composite electrode as a whole can be similar to an interdigitated micro-electrode array. In actual use, the composite electrode can adopt a two-electrode mode or a three-electrode mode (one of the grid electrode 7 and the three-dimensional nanoporous micro-pillar array electrode 6 is a working electrode, and the other is a counter electrode) to measure the impedance, capacitance and conductivity of the sample; it can also adopt a four-electrode mode (the grid electrode 7 and the three-dimensional nanoporous micro-pillar array electrode 6 are both independent working electrodes) to simultaneously control different electrochemical reactions, and can realize redox cycling and in-situ pH value control.

[0031] Furthermore, the grid electrode 7 and the three-dimensional nanoporous microcolumn array electrode 6 are both distributed in a three-dimensional space. Compared with the interdigitated microelectrode array, the composite electrode of the embodiment of the present invention can have a higher specific surface area, further reduce the electrode impedance and improve the signal-to-noise ratio, so that the composite electrode has a better detection sensitivity, and has many advantages of both the interdigitated microelectrode array and the three-dimensional microelectrode array, and can be applied to environmental testing, food safety, medical and other fields.

[0032] In addition, the two electrodes of the composite electrode are two different electrodes, namely a grid electrode 7 and a three-dimensional nanoporous microcolumn array electrode 6, which are different from the two electrodes in the interdigitated microelectrode array which are the same electrodes. Therefore, the embodiment of the present invention is conducive to enriching the structure of the microelectrode array, improving the detection performance and expanding the application field.

[0033] It should be understood that in the embodiment of the present invention, all meshes of the grid electrode 7 may be provided with nanoporous micro-pillar electrodes, and a single mesh may have one or more nanoporous micro-pillar electrodes; the grid electrode 7 may also have some meshes provided with nanoporous micro-pillar electrodes, some meshes not provided with nanoporous micro-pillar electrodes, and in the meshes provided with nanoporous micro-pillar electrodes, a single mesh may have one or more nanoporous micro-pillar electrodes; thereby, diverse needs can be met.

[0034] Further, the grid electrode 7 is an interconnected whole. The grid electrode 7 may include meshes and partition areas connected between the meshes, wherein the partition areas of the grid electrode 7 are arranged in a grid-shaped groove, and the partition areas in each grid-shaped groove are interconnected, thereby forming an interconnected grid electrode 7. The meshes of the grid electrode 7 correspond to the protrusions, and the grid electrode 7 has meshes arranged along the array, and all or part of the meshes are provided with nanoporous micro-pillar electrodes. In addition, the nanoporous micro-pillar electrodes are arranged in an array on the protrusions, thereby forming a three-dimensional nanoporous micro-pillar array electrode 6. Therefore, a three-dimensional nanoporous micro-pillar array-grid composite electrode can be formed.

[0035] Further, the diameter of the mesh is 100nm-1mm. Specifically, the diameter of the mesh can be 100nm, 120nm, 140nm, 160nm, 180nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, 10μm, 50μm, 80μm, 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm, 1mm, etc. In the same grid electrode 7, the diameters of different meshes can be the same or different. Since the mesh corresponds to the protrusion, the radial size of the protrusion can also be 100nm-1mm.

[0036] Further, the diameter of the nanoporous micro-pillar electrode is 50nm-500μm, and the length is 100nm-1mm. Specifically, the diameter of the nanoporous micro-pillar electrode can be 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 150nm, 180nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, 10μm, 50μm, 80μm, 100μm, 200μm, 300μm, 400μm, 500μm, etc. In addition, the length of the nanoporous micro-pillar electrode can be 100nm, 120nm, 140nm, 160nm, 180nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, 10μm, 50μm, 80μm, 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm, 1mm, etc. In the same three-dimensional nanoporous micro-pillar array electrode 6, the diameters and lengths of different nanoporous micro-pillar electrodes can be all the same, or partially the same, partially different, or all different, to form a diversified composite electrode.

[0037] A second aspect of an embodiment of the present invention provides a method for preparing a composite electrode, the method comprising:

[0038] Step 1: processing a grid-like groove on the surface of the substrate 1 to form a plurality of protrusions on the surface of the substrate 1, wherein the protrusions are separated from each other and arranged in an array;

[0039] Step 2, depositing a metal layer 2, an insulating layer 3 and a sacrificial layer 4 in sequence on the substrate 1 processed in step 1;

[0040] Step 3, heating one or more local micro-regions of the deposited layered structure of all or part of the protruding parts along the direction of the sacrificial layer 4 toward the insulating layer 3 and the metal layer 2 or along the direction of the metal layer 2 toward the insulating layer 3 and the sacrificial layer 4 to form a plurality of columnar metal molten regions with the two ends connected to the metal layer 2 and the sacrificial layer 4 and the middle penetrating the insulating layer 3, cooling and solidifying the columnar metal molten regions to form alloy micro-columns, and all the alloy micro-columns together constitute a three-dimensional alloy micro-column array 5;

[0041] Step 4, according to the electrochemical dealloying method, a three-electrode system is used to dissolve the material of the sacrificial layer 4 on the protrusion of the substrate 1, but retain the sacrificial layer 4 on the grid-shaped groove of the substrate 1, so that the sacrificial layer 4 is transformed into a grid electrode 7, and at the same time, the material of the sacrificial layer 4 in each alloy microcolumn is dissolved, so that a nanoporous structure 60 is generated in the microcolumn, and the alloy microcolumns are transformed into nanoporous microcolumns. All nanoporous microcolumns together constitute a three-dimensional nanoporous microcolumn array electrode 6, thereby obtaining a three-dimensional nanoporous microcolumn array-grid composite electrode; the material of the sacrificial layer 4 is the material of the grid electrode 7.

[0042] Specifically, the embodiment of the present invention forms protrusions on the surface of the substrate 1 by providing grid-shaped grooves on the surface of the substrate 1, so that the surface of the substrate 1 is undulating. Along the axial direction of the substrate 1, the metal layer 2, the insulating layer 3 and the sacrificial layer 4 are sequentially deposited on the undulating surface of the substrate 1, so that the metal layer 2, the insulating layer 3 and the sacrificial layer 4 are all undulating. Therefore, when the electrochemical dealloying treatment of step 4 is performed, the material of the sacrificial layer 4 on the protrusion of the substrate 1 can be dissolved, while the sacrificial layer 4 in the grid-shaped grooves of the substrate 1 is retained, and the retained sacrificial layer 4 is connected to each other to be transformed into a grid electrode 7.

[0043] In addition, the metal layer 2, the insulating layer 3 and the sacrificial layer 4 form a layered structure, and the layered structure on a protrusion may have 0, 1 or more micro-regions. These micro-regions are heated, so that a metal molten region with two ends connected to the metal layer 2 and the sacrificial layer 4 and the insulating layer 3 in the middle can be formed above the protrusion, and then the columnar metal molten region is cooled and solidified to form an alloy micro-column, and finally a three-dimensional alloy micro-column array 5 composed of all the alloy micro-columns is obtained. Similarly, through the electrochemical dealloying treatment in step 4, the material of the sacrificial layer 4 of the alloy micro-columns in the three-dimensional alloy micro-column array 5 is dissolved, and the atoms of the material of the metal layer 2 retained in the alloy micro-columns are reunited through the dealloying interface diffusion, so that the three-dimensional alloy micro-column array 5 can be transformed into a three-dimensional nanoporous micro-column array, that is, a three-dimensional nanoporous micro-column array electrode 6 can be obtained.

[0044] Through the above steps, a three-dimensional nanoporous micro-pillar array-grid composite electrode can be obtained. Since the nanoporous micro-pillar electrodes of the three-dimensional nanoporous micro-pillar array electrode 6 correspond to the protrusions, and the grid electrode 7 corresponds to the grid-shaped grooves, the nanoporous micro-pillar electrodes of the three-dimensional nanoporous micro-pillar array electrode 6 are arranged in the mesh of the grid electrode 7, that is, the three-dimensional nanoporous micro-pillar array electrode 6 is tightly surrounded by the grid electrode 7, so that the composite electrode as a whole can be similar to an interdigitated microelectrode array.

[0045] The embodiment of the present invention obtains a three-dimensional nanoporous micro-pillar array by organically integrating surface engraving, micro-area heating, and electrochemical gold removal, without using cumbersome and expensive photolithography or nanoimprinting technology. The preparation method is relatively simple, has low production conditions, low cost, and is suitable for large-scale production. In the step of preparing the grid electrode 7, after step 1, the remaining steps 2 and 4 are overlapped with the preparation steps of the three-dimensional nanoporous micro-pillar array electrode 6, so that in the step of preparing the grid electrode 7, there are no other additional preparation steps, which can further simplify the preparation method and reduce production costs.

[0046] Step 1: Processing grid-shaped grooves on the surface of the substrate 1 to form a plurality of protrusions on the surface of the substrate 1. The protrusions are separated from each other and arranged in an array.

[0047] Specifically, the surface processing of the substrate 1 in step 1 adopts at least one method selected from laser etching, plasma etching, chemical etching, mechanical engraving or embossing. By processing a grid-like groove on the surface of the substrate 1, a plurality of protrusions are formed on the surface of the substrate 1. On the one hand, the protrusions are separated from each other and arranged in an array, which can define the distribution area of ​​the three-dimensional alloy micro-pillar array 5, so that the three-dimensional nanoporous micro-pillar array electrode 6 is formed on the protrusions; on the other hand, the layered structure in step 2 can be made uneven, so that the sacrificial layer 4 can be transformed into a grid electrode 7 after step 4.

[0048] Further, in step 1, the cross-sectional shape of the grid-shaped grooves of the substrate 1 is V-shaped, U-shaped, arc-shaped, rectangular, trapezoidal or other irregular shapes, and the cross-sectional shapes of different grooves of the same grid-shaped groove can be the same or different. The protrusions are formed between the grid-shaped grooves, so that the cross-sectional shape of the protrusions can also be determined according to the cross-sectional shape of the grid-shaped grooves.

[0049] Step 2: depositing a metal layer 2, an insulating layer 3 and a sacrificial layer 4 in sequence on the substrate 1 processed in step 1.

[0050] Step 2 specifically includes the following steps: Step 21, depositing a metal layer 2 on the surface of the grid-shaped grooves and protrusions to form a bumpy metal layer 2; Step 22, depositing an insulating layer 3 on the side of the metal layer 2 away from the substrate 1 to form a bumpy insulating layer 3; Step 23, depositing a sacrificial layer 4 on the side of the insulating layer 3 away from the metal layer 2 to form a bumpy insulating layer 3.

[0051] Furthermore, magnetron sputtering is used for deposition in step 2. In other embodiments, other physical vapor deposition methods, or chemical vapor deposition, electrochemical deposition, hot dipping, spraying, spin coating, dip coating, screen printing and other methods may also be used for deposition.

[0052] Further, the metal layer 2 may have one or more layers. The material of the metal layer 2 may be a metal element or an alloy. In a multi-layer metal layer, multiple metal layers are deposited in sequence, and the materials of the metal layers 2 of different layers may be the same or different. Therefore, different metal materials may be selected as components of the metal layer 2 according to actual needs, so that the finally formed three-dimensional nanoporous microcolumn array electrode 6 may have different metal compositions to meet diverse needs.

[0053] Furthermore, in the electrochemical dealloying treatment of step 4, the activity of the materials of the metal layer 2 and the sacrificial layer 4 is required, that is, the activity of the material of the sacrificial layer 4 is generally higher than that of the material of the metal layer 2. Therefore, it is necessary to comprehensively consider the material of the metal layer 2 and the material of the sacrificial layer 4, that is, to select a good material combination of the metal layer 2 and the sacrificial layer 4. Generally, the material of the sacrificial layer 4 can be selected according to the material of the metal layer 2. Exemplarily, the material combination of the metal layer 2 and the sacrificial layer 4 can be one of gold-silver (Au-Ag), gold-aluminum (Au-Al), gold-zinc (Au-Zn), platinum-silver (Pt-Ag), platinum-copper (Pt-Cu), silver-aluminum (Ag-Al), silver-zinc (Ag-Zn), silver-magnesium (Ag-Mg), palladium-cobalt (Pd-Co), palladium-aluminum (Pd-Al), copper-aluminum (Cu-Al), copper-zirconium (Cu-Zr), copper-manganese (Cu-Mn), bismuth-tin (Bi-Sn), bismuth-lead (Bi-Pb) and titanium-magnesium (Ti-Mg). In addition, the material of the grid electrode 7 is the material of the sacrificial layer 4, so the activity of the material of the grid electrode 7 is higher than the activity of the material of the metal layer 2.

[0054] Step 3, heating one or more local micro-regions of the deposited layered structure of all or part of the protrusions along the direction of the sacrificial layer 4 toward the insulating layer 3 and the metal layer 2 or along the direction of the metal layer 2 toward the insulating layer 3 and the sacrificial layer 4 to form a plurality of columnar metal molten regions with the two ends connected to the metal layer 2 and the sacrificial layer 4 and the middle penetrating the insulating layer 3, cooling and solidifying the columnar metal molten regions to form alloy micro-columns, and all the alloy micro-columns together constitute a three-dimensional alloy micro-column array 5.

[0055] Specifically, in step 3, laser heating or electron beam heating is used for micro-area heating. When the material of the substrate 1 is ceramic or opaque material, the micro-area can be heated along the sacrificial layer 4 toward the insulating layer 3 and the metal layer 2; when the substrate 1 is a material with good light transmittance such as sapphire glass, a laser heating method can be selected to allow the laser to directly irradiate the metal layer 2 through the substrate 1, so that the micro-area heating direction is from the metal layer 2 to the insulating layer 3 and the sacrificial layer 4. The layered structure deposited on all protrusions has 1 or more micro-areas, or the layered structure deposited on part of the protrusions has 1 or more micro-areas, and the layered structure deposited on part of the protrusions does not set micro-areas, and it is only necessary to ensure that the micro-areas are arranged in an array. The irradiation area can be adjusted so that a three-dimensional nanoporous micro-pillar array electrode 6 with a specific distribution is finally formed, thereby realizing the designability and controllability of the three-dimensional nanoporous micro-pillar array electrode 6 at the micrometer scale.

[0056] Furthermore, the shape and diameter of the columnar metal molten area can be determined by controlling the laser power and the laser spot size, so that a three-dimensional nanoporous micro-pillar array electrode 6 with a specific structure can be finally formed, so that the three-dimensional nanoporous micro-pillar array electrode 6 has a high degree of designability and controllability at the micrometer scale. For example, the diameter of the alloy micro-pillar is 50nm to 500μm, and the length is 100nm to 1mm, so that the diameter of the nanoporous micro-pillar electrode is 50nm to 500μm, and the length is 100nm to 1mm.

[0057] It can be understood that the two ends of the columnar metal molten area connect the metal layer 2 and the sacrificial layer 4, and the middle passes through the insulating layer 3, and the alloy microcolumn is formed by cooling and solidification of the columnar metal molten area, and the alloy microcolumn contains the material of the metal layer 2 and the material of the sacrificial layer 4.

[0058] Step 4, according to the electrochemical dealloying method, a three-electrode system is used to dissolve the material of the sacrificial layer 4 on the protrusion of the substrate 1, but retain the sacrificial layer 4 on the grid-shaped groove of the substrate 1, so that the sacrificial layer 4 is transformed into a grid electrode 7, and at the same time, the material of the sacrificial layer 4 in each alloy microcolumn is dissolved, so that a nanoporous structure 60 is generated in the microcolumn, and the alloy microcolumns are transformed into nanoporous microcolumns. All nanoporous microcolumns together constitute a three-dimensional nanoporous microcolumn array electrode 6, thereby obtaining a three-dimensional nanoporous microcolumn array-grid composite electrode; the material of the sacrificial layer 4 is the material of the grid electrode 7.

[0059] Specifically, the electrochemical dealloying method used in step 4 is a constant potential electrochemical dealloying method. Through the electrochemical dealloying treatment, the material of the sacrificial layer 4 in the alloy microcolumn can be dissolved, so that the atoms of the material of the metal layer 2 diffuse through the solid-liquid interface and re-agglomerate, thereby transforming the alloy microcolumn into a nanoporous microcolumn mainly containing the material of the metal layer 2, and the nanoporous microcolumn contains a plurality of nanoporous structures 60. The microregions are arranged in an array, the alloy microcolumns are arranged in an array correspondingly, and thus the nanoporous microcolumns are arranged in an array correspondingly, forming a three-dimensional nanoporous microcolumn array electrode 6.

[0060] Furthermore, the nanoporous microcolumn has a nanoporous structure 60. In the same nanoporous microcolumn, the shapes of the nanoporous structures 60 are partially the same, partially different, or completely different; and the sizes of the various nanoporous structures 60 are partially the same, partially different, or completely different. The nanoporous structures 60 are interconnected, and the pore walls of the nanoporous structures 60 are interconnected; the diameter of the nanoporous structure 60 is 1nm to 500nm, and the thickness of the pore wall is 1nm to 500nm. The pore walls of the various nanoporous structures 60 are interconnected, so that the entire three-dimensional nanoporous microcolumn array can form a good conductive connection with the metal layer 2, effectively increasing the electrochemical active area of ​​the three-dimensional nanoporous microelectrode array.

[0061] It should be understood that the nanoporous structure 60 of the three-dimensional nanoporous microcolumn in the figure is only a schematic diagram. In actual situations, the nanoporous structure 60 is not just a regular circle, but a variety of irregular shapes. The structure of the three-dimensional nanoporous microcolumn should be like a sponge structure or a steel ball structure. In the process of dissolving the material of the sacrificial layer 4 in the three-dimensional alloy microcolumn array 5, the control and optimization of the nanoporous structure can be achieved by adjusting the dealloying temperature, dealloying current density, surfactant and other influencing factors, thereby achieving the designability and controllability of the three-dimensional nanoporous microcolumn array electrode 6 at the nanoscale, and a variety of three-dimensional nanoporous microelectrode arrays can be designed and prepared to meet the needs of different styles of microelectrode arrays in practical applications, which is very suitable for applications in sensors, microelectronics, electrocatalysis and energy storage.

[0062] Furthermore, in some embodiments, the three-dimensional alloy micro-column array 5 may be partially dealloyed without converting the entire alloy micro-column into a nanoporous structure, thereby effectively shortening the electrochemical dealloying time.

[0063] Furthermore, the preparation method of the three-dimensional nanoporous micropillar array-grid composite electrode is further described below through specific examples. It should be understood that the specific examples described here are only used to explain the present invention, rather than to limit the present invention.

[0064] Embodiment 1:

[0065] Step 1, a ceramic sheet is selected as the substrate 1, and a grid-like groove (the cross-sectional shape of the grid-like groove is V-shaped) is processed on the surface of the substrate 1 by a laser etching method, and the protrusions formed by segmentation form a square array (the side length of the square is 100 μm, and the diameter of the protrusion is 60 μm);

[0066] Step 2: Using a magnetron sputtering method, a gold (Au) layer, a silicon dioxide (SiO2) layer and a silver (Ag) layer are sequentially deposited on a substrate 1 as a metal layer 2, an insulating layer 3 and a sacrificial layer 4, and their thicknesses are 20 μm, 50 nm and 20 μm, respectively;

[0067] Step 3, using a laser heating method, heating is performed from the central micro-region of the sacrificial layer 4 on each protrusion toward the insulating layer 3 and the metal layer 2 (the sacrificial layer 4 on each protrusion has a central micro-region, and a single central micro-region corresponds to the central position of the upper surface of the sacrificial layer 4 on a single protrusion, and the diameter of the single central micro-region is 10 μm), and a columnar metal molten region is formed under each central micro-region, with the two ends connecting the metal layer 2 and the sacrificial layer 4 and the middle penetrating the insulating layer 3, and then each columnar metal molten region is cooled and solidified, so that an alloy micro-column is formed at the central position of each protrusion, so that each alloy micro-column together constitutes a three-dimensional alloy micro-column array 5;

[0068] Step 4, using a constant potential electrochemical dealloying method (selecting a three-electrode system of an electrochemical workstation, the working electrode is connected to the metal layer 2, the counter electrode is a platinum electrode, the reference electrode is a mercury / mercurous sulfate reference electrode (MSE), the electrolyte is a 0.1M perchloric acid (HClO4) solution, and the dealloying potential is 0.55V), the material (silver component) of the sacrificial layer 4 in the three-dimensional alloy micro-pillar array 5 is dissolved, so that the three-dimensional alloy micro-pillar array 5 is transformed into a three-dimensional nanoporous micro-pillar array electrode 6 of gold (Au), and at the same time, the sacrificial layer 4 of the protrusion is dissolved, while the sacrificial layer 4 in the grid-shaped groove is retained, and the retained sacrificial layer 4 is transformed into a grid electrode 7, and finally a three-dimensional nanoporous micro-pillar array-grid composite electrode is obtained.

[0069] Embodiment 2:

[0070] Step 1, a ceramic sheet is selected as the substrate 1, and a grid-like groove (the cross-sectional shape of the grid-like groove is V-shaped) is processed on the surface of the substrate 1 by a laser etching method, and the protrusions formed by segmentation form an equilateral triangle array (the side length of the equilateral triangle is 100 μm, and the diameter of the protrusion is 60 μm);

[0071] Step 2: Using a magnetron sputtering method, a gold (Au) layer, a silicon dioxide (SiO2) layer and a silver (Ag) layer are sequentially deposited on a substrate 1 as a metal layer 2, an insulating layer 3 and a sacrificial layer 4, and their thicknesses are 20 μm, 50 nm and 20 μm, respectively;

[0072] Step 3, using a laser heating method, heating is performed from the central micro-region of the sacrificial layer 4 on each protrusion toward the insulating layer 3 and the metal layer 2 (the sacrificial layer 4 on each protrusion has a central micro-region, and a single central micro-region corresponds to the central position of the upper surface of the sacrificial layer 4 on a single protrusion, and the diameter of the single central micro-region is 10 μm), and a columnar metal molten region is formed under each central micro-region, with the two ends connecting the metal layer 2 and the sacrificial layer 4 and the middle penetrating the insulating layer 3, and then each columnar metal molten region is cooled and solidified, so that an alloy micro-column is formed at the central position of each protrusion, so that each alloy micro-column together forms a three-dimensional alloy micro-column array 5;

[0073] Step 4, using a constant potential electrochemical dealloying method (selecting a three-electrode system of an electrochemical workstation, the working electrode is connected to the metal layer 2, the counter electrode is a platinum electrode, the reference electrode is a mercury / mercurous sulfate reference electrode (MSE), the electrolyte is a 0.1M perchloric acid (HClO4) solution, and the dealloying potential is 0.55V), the material (silver component) of the sacrificial layer 4 in the three-dimensional alloy micro-pillar array 5 is dissolved, so that the three-dimensional alloy micro-pillar array 5 is transformed into a three-dimensional nanoporous micro-pillar array electrode 6 of gold (Au), and at the same time, the sacrificial layer 4 on each protrusion is dissolved, while the sacrificial layer 4 in the grid-shaped groove is retained, and the retained sacrificial layer 4 is transformed into a grid electrode 7, and finally a three-dimensional nanoporous micro-pillar array-grid composite electrode is obtained.

[0074] Embodiment 3:

[0075] Step 1, a quartz glass sheet is selected as the substrate 1, and a grid-like groove (the cross-sectional shape of the grid-like groove is U-shaped) is processed on the surface of the substrate 1 by a laser etching method, and the protrusions formed by segmentation form a square array (the side length of the square is 100 μm, and the diameter of the protrusion is 60 μm);

[0076] Step 2: Using a magnetron sputtering method, a bismuth (Bi) layer, a silicon dioxide (SiO2) layer and a tin (Sn) layer are sequentially deposited on the substrate 1 as the metal layer 2, the insulating layer 3 and the sacrificial layer 4, and their thicknesses are 20 μm, 50 nm and 20 μm respectively;

[0077] Step 3, using a laser heating method, heating is performed from the central micro-region of the sacrificial layer 4 on each protrusion toward the insulating layer 3 and the metal layer 2 (the sacrificial layer 4 on each protrusion has a central micro-region, and a single central micro-region corresponds to the central position of the upper surface of the sacrificial layer 4 on a single protrusion, and the diameter of the single central micro-region is 10 μm), and a columnar metal molten region is formed under each central micro-region, with the two ends connecting the metal layer 2 and the sacrificial layer 4 and the middle penetrating the insulating layer 3, and then each columnar metal molten region is cooled and solidified, so that an alloy micro-column is formed at the central position on each protrusion, so that each alloy micro-column together constitutes a three-dimensional alloy micro-column array 5;

[0078] Step 4, using a constant potential electrochemical dealloying method (selecting a three-electrode system of an electrochemical workstation, the working electrode is connected to the metal layer 2, the counter electrode is a platinum electrode, the reference electrode is a mercury / mercurous sulfate reference electrode (MSE), the electrolyte is a 0.25M sulfuric acid (H2SO4) solution, and the dealloying potential is -0.55V), the material (tin component) of the sacrificial layer 4 in the three-dimensional alloy micro-pillar array 5 is dissolved, so that the three-dimensional alloy micro-pillar array 5 is transformed into a three-dimensional nanoporous micro-pillar array electrode 6 of bismuth (Bi), and at the same time, the sacrificial layer 4 on each protrusion is dissolved, while the sacrificial layer 4 in the grid-shaped groove is retained, and the retained sacrificial layer 4 is transformed into a grid electrode 7, and finally a three-dimensional nanoporous micro-pillar array-grid composite electrode is obtained.

[0079] Embodiment 4:

[0080] Step 1, a sapphire glass sheet is selected as the substrate 1, and a grid-like groove (a cross-sectional shape of the grid-like groove is V-shaped) is processed on the surface of the substrate 1 by a laser etching method, and the protrusions of the substrate 1 formed by segmentation form a square array (the side length of the square is 100 μm, and the diameter of the protrusion is 60 μm);

[0081] Step 2: Using a magnetron sputtering method, a gold (Au) layer, a silicon dioxide (SiO2) layer and a silver (Ag) layer are sequentially deposited on a substrate 1 as a metal layer 2, an insulating layer 3 and a sacrificial layer 4, and their thicknesses are 20 μm, 50 nm and 20 μm, respectively;

[0082] Step 3, using a laser heating method, the laser passes through the substrate 1, and heats the insulating layer 3 and the sacrificial layer 4 from the central micro-region of the metal layer 2 on each protrusion (the metal layer 2 on each protrusion has a central micro-region, and a single central micro-region corresponds to the central position of the lower surface of the metal layer 2 on a single protrusion, and the diameter of the single central micro-region is 10 μm), and a columnar metal molten area is formed above each central micro-region, with the two ends connecting the metal layer 2 and the sacrificial layer 4 and the middle penetrating the insulating layer 3, and then each columnar metal molten area is cooled and solidified, so that an alloy micro-column is formed at the central position on each protrusion, so that each alloy micro-column together forms a three-dimensional alloy micro-column array 5;

[0083] Step 4, using a constant potential electrochemical dealloying method (selecting a three-electrode system of an electrochemical workstation, the working electrode is connected to the metal layer 2, the counter electrode is a platinum electrode, the reference electrode is a mercury / mercurous sulfate reference electrode (MSE), the electrolyte is a 0.1M perchloric acid (HClO4) solution, and the dealloying potential is 0.55V), the material (silver component) of the sacrificial layer 4 in the three-dimensional alloy micro-pillar array 5 is dissolved, so that the three-dimensional alloy micro-pillar array 5 is transformed into a three-dimensional nanoporous micro-pillar array electrode 6 of gold (Au), and at the same time, the sacrificial layer 4 on each protrusion is dissolved, while the sacrificial layer 4 of the grid-shaped groove is retained, and the retained sacrificial layer 4 is transformed into a grid electrode 7, and finally a three-dimensional nanoporous micro-pillar array-grid composite electrode is obtained.

[0084] Embodiment 5:

[0085] Step 1, a ceramic sheet is selected as the substrate 1, and a grid-like groove (the cross-sectional shape of the grid-like groove is V-shaped) is processed on the surface of the substrate 1 by a laser etching method, and the protrusions formed by segmentation form a square array (the side length of the square is 100 μm, and the diameter of the protrusion is 60 μm);

[0086] Step 2: Using a magnetron sputtering method, a gold (Au) layer, a silicon dioxide (SiO2) layer and a silver (Ag) layer are sequentially deposited on a substrate 1 as a metal layer 2, an insulating layer 3 and a sacrificial layer 4, and their thicknesses are 20 μm, 50 nm and 20 μm, respectively;

[0087] Step 3, using a laser heating method, heating the insulating layer 3 and the metal layer 2 from two micro-regions of the sacrificial layer 4 on each protrusion (the sacrificial layer 4 on each protrusion has two micro-regions, a single micro-region is arranged on the upper surface of the sacrificial layer 4 of a single protrusion, and the diameter of a single micro-region is 10 μm), and a columnar metal molten area with two ends connected to the metal layer 2 and the sacrificial layer 4 and the middle penetrating the insulating layer 3 is formed under each micro-region, and then each columnar metal molten area is cooled and solidified, so that two alloy micro-columns are formed on each protrusion, so that each alloy micro-column together forms a three-dimensional alloy micro-column array 5;

[0088] Step 4, using a constant potential electrochemical dealloying method (selecting a three-electrode system of an electrochemical workstation, the working electrode is connected to the metal layer 2, the counter electrode is a platinum electrode, the reference electrode is a mercury / mercurous sulfate reference electrode (MSE), the electrolyte is a 0.1M perchloric acid (HClO4) solution, and the dealloying potential is 0.55V), the material (silver) of the sacrificial layer 4 in the three-dimensional alloy micro-pillar array 5 is dissolved, so that the three-dimensional alloy micro-pillar array 5 is transformed into a three-dimensional nanoporous micro-pillar array electrode 6 of gold (Au), and at the same time, the sacrificial layer 4 on each protrusion is dissolved, while the sacrificial layer 4 of the grid-shaped groove is retained, and the retained sacrificial layer 4 is transformed into a grid electrode 7, and finally a three-dimensional nanoporous micro-pillar array-grid composite electrode is obtained.

[0089] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0090] The above is a description of the technical solution provided by the present invention. For those skilled in the art, according to the ideas of the embodiments of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for preparing a composite electrode, characterized in that: The method comprises: Step 1: processing a grid-shaped groove on the surface of the substrate (1) to form a plurality of protrusions on the surface of the substrate (1), wherein the protrusions are separated from each other and arranged in an array; Step 2: depositing a metal layer (2), an insulating layer (3) and a sacrificial layer (4) in sequence on the substrate (1) processed in step 1; the metal layer (2), the insulating layer (3) and the sacrificial layer (4) all have an undulating shape; Step 3, heating one or more local micro-regions of the deposited layered structure of all or part of the protruding parts along the direction from the sacrificial layer (4) to the insulating layer (3) and the metal layer (2) or along the direction from the metal layer (2) to the insulating layer (3) and the sacrificial layer (4) to form a plurality of columnar metal molten regions with two ends connected to the metal layer (2) and the sacrificial layer (4) and the middle penetrating the insulating layer (3), cooling and solidifying the columnar metal molten regions to form alloy micro-columns, and all the alloy micro-columns together constitute a three-dimensional alloy micro-column array (5); wherein the micro-region heating is performed by a laser heating method or an electron beam heating method; Step 4: According to the electrochemical dealloying method, a three-electrode system is used to dissolve the material of the sacrificial layer (4) on the protruding portion of the substrate (1), but retain the sacrificial layer (4) on the grid-shaped groove of the substrate (1), so that the sacrificial layer (4) is transformed into a grid electrode (7), and at the same time, the material of the sacrificial layer (4) in each alloy microcolumn is dissolved, so that a nanoporous structure (60) is generated in the microcolumn, and the alloy microcolumns are transformed into nanoporous microcolumns. All nanoporous microcolumns together constitute a three-dimensional nanoporous microcolumn array electrode (6), thereby obtaining a three-dimensional nanoporous microcolumn array-grid composite electrode; The material of the sacrificial layer (4) is the material of the grid electrode (7); The material of the substrate (1) is at least one of ceramic, sapphire glass, quartz glass, borosilicate glass or aluminosilicate glass; The material of the metal layer (2) is one of gold, platinum, silver, palladium, copper, bismuth or titanium; The material of the insulating layer (3) is at least one of silicon dioxide, silicon nitride or a non-conductive polymer; The material of the three-dimensional nanoporous micro-pillar array electrode (6) includes the material of the metal layer (2); The material of the grid electrode (7) is a metal with higher activity than the material of the metal layer (2).

2. The preparation method according to claim 1, characterized in that: The surface processing of the substrate (1) in step 1 adopts at least one method selected from the group consisting of laser etching, plasma etching, chemical etching, mechanical engraving or embossing.

3. The preparation method according to claim 1, characterized in that: In the step 1, the cross-sectional shape of the grid-shaped grooves of the substrate (1) is at least one of a V-shape, an arc shape, a rectangle or a trapezoid.

4. The preparation method according to claim 1, characterized in that: In step 2, the deposition method is at least one of physical vapor deposition, chemical vapor deposition, electrochemical deposition, spraying, spin coating, dip coating or screen printing.

5. The preparation method according to claim 1, characterized in that: The electrochemical dealloying method used in step 4 is a constant potential electrochemical dealloying method.

6. The preparation method according to claim 1, characterized in that: The diameter of the nanoporous microcolumn is 50nm-500μm, and the length is 100nm-1mm.

7. A composite electrode prepared according to the preparation method according to any one of claims 1 to 6.

Images