Boron-doped diamond and MOFs derivative composite electrode and preparation method thereof
By preparing a composite electrode of boron-doped diamond and MOFs derivatives, the problem of poor conductivity of metal oxides was solved, the high sensitivity and long life of the electrochemical biosensor were achieved, and the production process was simplified.
Patent Information
- Application Number
- CN202510967218.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-14
- Publication Date
- 2025-10-03
AI Technical Summary
Metal oxides have poor electrical conductivity, resulting in insufficient sensitivity and selectivity in electrochemical biosensors.
A composite electrode of boron-doped diamond and MOFs derivatives is used. Boron-doped diamond is prepared by chemical vapor deposition, oxygen plasma etching is used to form nano-grooves on its surface, and porous metal oxide is in situ grown on it to form a highly conductive composite electrode.
The response sensitivity and service life of the electrode are improved, the production process is simplified, and a sensing electrode with a high active specific surface area is obtained.
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Figure CN120741594A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a composite electrode material, in particular to a composite electrode of boron-doped diamond and MOFs derivatives and a preparation method thereof. Background Art
[0002] Electrochemical biosensors are a type of sensor that selectively reacts with typical biomarkers on a recognition element and generates an electrical signal in response. Most commercial electrochemical biosensors, such as enzyme-based biosensors, immunosensors, and DNA hybridization biosensors, utilize biosensing elements with excellent sensitivity and selectivity. However, these electrochemical biosensors have limitations due to their complex anchoring process, high cost, poor stability, and sensitivity to environmental factors (such as temperature, pH, oxygen, and some inactivators). In contrast, metal oxides offer advantages such as low cost, easy synthesis, strong catalytic activity, and high biocompatibility, and exhibit broad application prospects in the field of electrochemical biosensors. However, their poor electrical conductivity significantly hinders their application in electrochemical biomarker recognition. Therefore, considerable effort has been devoted to integrating sensitive identifiers with highly conductive nanostructures. Summary of the Invention
[0003] The present invention aims to solve the problem of poor sensitivity and selectivity of corresponding electrochemical biosensors caused by the low electrical conductivity of metal oxides themselves.
[0004] In order to solve the above problems, the technical solution provided by the present invention is: a composite electrode of boron-doped diamond and MOFs derivatives, which comprises, from bottom to top, a substrate, a boron-doped diamond with nanogrooves on the surface, and a porous metal oxide derived from MOFs.
[0005] In the above solution, the substrate material is non-metallic silicon, silicon dioxide or metallic titanium, niobium.
[0006] In the above solution, the boron-doped diamond is prepared by chemical vapor deposition and has a thickness of 5 to 20 μm.
[0007] In the above scheme, the nano-grooves on the surface of the boron-doped diamond are produced by oxygen plasma etching, with a depth of 1-2 μm.
[0008] In the above scheme, the MOFs-derived porous metal oxide is prepared by oxygen plasma etching of MOFs grown in situ on the surface of boron-doped diamond, with a height of 0.5~1.5 μm.
[0009] The present invention also provides a method for preparing a composite electrode of boron-doped diamond and MOFs derivatives, comprising the following steps: (1) Roughen the substrate surface by wet chemical etching or sandblasting; (2) Using ultrasonic method to clean and seed the substrate; (3) Depositing a layer of boron-doped diamond on the surface of the substrate using chemical vapor deposition; (4) Using UV-ozone activation method to improve the hydrophilicity of the boron-doped diamond surface; (5) In situ growth of MOFs on the surface of boron-doped diamond using a solvothermal method; (6) Oxygen plasma etching is used to convert MOFs into porous metal oxides, while nanogrooves are formed on the surface of the underlying boron-doped diamond.
[0010] In the above scheme, the substrate in step (1) is non-metallic silicon, silicon dioxide or metallic titanium, niobium. For non-metallic silicon or silicon dioxide substrates, the roughening treatment adopts wet chemical etching method, immersing the substrate in an alkaline solution and heating it in a water bath at 50-90°C for 0.5-2 hours. The alkali in the alkaline solution is sodium hydroxide or potassium hydroxide with a mass fraction of 5-20%. For metallic titanium or niobium substrates, the roughening treatment adopts sandblasting method, using 80-120 mesh corundum sand, compressed air pressure of 0.5-0.8MPa, and spray distance of 20-30 cm.
[0011] In the above scheme, step (2) ultrasonically cleans the substrate using acetone, anhydrous ethanol, and ultrapure water, respectively, for 10 minutes. The substrate is then immersed in a suspension containing nanodiamond seed crystals and ultrasonically cleaned for 20 minutes. The nanodiamond seed crystals have a particle size of 5 to 20 nm and a mass fraction of 15% in the suspension.
[0012] In the above scheme, step (3) uses methane as the carbon source with a volume ratio of 1-5%, hydrogen as the auxiliary gas with a volume ratio of 95-99%, trimethylborane as the boron source, the mass concentration of boron in the mixed gas ranges from 6000 to 8000 ppm, the reaction temperature is 450-650°C, the reaction time is 5-20 hours, and a boron-doped diamond film with a thickness of 5-20 μm is deposited on a single crystal silicon substrate.
[0013] In the above scheme, the oxygen flux in step (4) is 0.5 to 1 cm 3 min -1 , the heating temperature is 50-100℃, and the ultraviolet irradiation time is 5-15 min.
[0014] In the above scheme, in step (5), the metal salt and the organic ligand are dissolved in 60 ml of deionized water, and then transferred to a 100 ml polytetrafluoroethylene-lined autoclave containing a boron-doped diamond substrate, and heated at 85-120°C for 30-120 min; the metal salt is a nitrate, acetate or chloride of zinc, cobalt, nickel, manganese, aluminum, iron or copper; the organic ligand is methylimidazole, terephthalic acid or trimesic acid; and the molar ratio of the metal salt to the organic ligand is 1:1-1:6.
[0015] In the above scheme, the oxygen pressure in step (6) is 10-20 Pa, and the oxygen flux is 10-20 cm 3 s -1 , plasma power is 100-150 W, and etching time is 30-90 min.
[0016] The present invention has the following beneficial effects: (1) Combining metal oxides with selective recognition but poor conductivity with boron-doped diamond, which has low background current, good stability, and strong conductivity, can effectively improve the response sensitivity and service life of the electrode; (2) The MOFs grown in situ on the surface of boron-doped diamond are converted into porous metal oxides by oxygen plasma etching. This not only avoids the agglomeration of nanoparticles caused by annealing, but also forms nanogrooves on the surface of boron-doped diamond, thereby obtaining a sensing electrode with a high active specific surface area through a simple production process. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 A simplified schematic diagram of the process for preparing a composite electrode of boron-doped diamond and MOFs derivatives provided by the present invention; In the figure, 1 is a substrate; 2 is a conventional boron-doped diamond; 3 is a MOFs array; 4 is a boron-doped diamond with nanogrooves on the surface; 5 is a porous metal oxide derived from MOFs; Figure 2 The differential pulse voltammetric response signals of the composite electrode of boron-doped diamond and MOFs derivatives provided by the present invention and a conventional boron-doped diamond electrode in a buffer solution (0.1 M PBS, pH = 7.6) with the same dopamine concentration (100 μM); in the figure, I is a conventional boron-doped diamond electrode, and II is a composite electrode of boron-doped diamond and MOFs derivatives provided by the present invention; Figure 3 The differential pulse voltammetric response signal of the composite electrode of boron-doped diamond and MOFs derivatives provided by the present invention in a buffer solution (0.1 M PBS, pH = 7.6) with different dopamine concentrations (0-150 μM); Figure 4The present invention provides a fitting curve showing the change in peak current of the composite electrode of boron-doped diamond and MOFs derivatives with dopamine concentration. DETAILED DESCRIPTION
[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings.
[0019] This embodiment provides a composite electrode of boron-doped diamond and MOFs derivatives.
[0020] In this embodiment, the substrate is silicon, the thickness of the boron-doped diamond is 10 μm, the depth of the nano-grooves is 1 μm, and the MOFs derivative is porous copper oxide with a height of 1.5 μm.
[0021] The preparation method of the composite electrode of boron-doped diamond and MOFs derivatives is as follows: Figure 1 As shown, the following steps are included: (1) The surface of the substrate silicon 1 was roughened by wet chemical etching. The substrate was immersed in a 20% by mass sodium hydroxide solution and heated at 50°C in a water bath for 2 h.
[0022] (2) The substrate was cleaned using acetone, anhydrous ethanol, and ultrapure water, respectively, for 10 minutes using an ultrasonic method. The substrate was then immersed in a suspension containing nanodiamond seed crystals and ultrasonicated for 20 minutes. The nanodiamond seed crystals had a particle size of 5 nm and a mass fraction of 5% in the suspension.
[0023] (3) A boron-doped diamond film 2 with a thickness of 10 μm was deposited on a single crystal silicon 1 by chemical vapor deposition, using methane as a carbon source with a volume ratio of 5%, hydrogen as an auxiliary gas with a volume ratio of 95%, trimethylborane as a boron source, and a boron mass concentration range of 8000 ppm in the mixed gas. The reaction temperature was 650°C, and the reaction time was 10 h.
[0024] (4) The UV-ozone activation method was used to improve the hydrophilicity of the boron-doped diamond surface. The oxygen flux was 1 cm 3 min -1 , the heating temperature was 80℃, and the UV irradiation time was 15 min.
[0025] (5) Using a solvent thermal method, copper nitrate and trimesic acid (molar ratio 1:3) were dissolved in 60 ml of deionized water and then transferred to a 100 ml polytetrafluoroethylene-based autoclave containing a boron-doped diamond substrate. The solution was heated at 120 °C for 60 min to in situ grow a copper-based MOFs array 3 on the boron-doped diamond surface.
[0026] (6) The copper-based MOFs array was converted into porous copper oxide 5 by oxygen plasma etching, and nano-grooves 4 were formed on the surface of the underlying boron-doped diamond. The operating oxygen pressure was 20 Pa and the oxygen flux was 20 cm 3 s -1 , plasma power is 150 W, and etching time is 60 min.
[0027] Figure 2 The differential pulse voltammetric response signals of the boron-doped diamond and MOFs derivative composite electrode provided by the present invention and a conventional boron-doped diamond electrode in a buffer solution (0.1 M PBS, pH = 7.6) with the same dopamine concentration (100 μM). In the figure, I is a conventional boron-doped diamond electrode, and II is a boron-doped diamond and MOFs derivative composite electrode provided by the present invention. As shown in the figure, in a buffer solution (0.1 M PBS, pH = 7.6) with the same dopamine concentration (100 μM), the boron-doped diamond and MOFs derivative composite electrode provided by the present invention can provide a higher differential pulse voltammetric response signal than the conventional boron-doped diamond electrode, indicating that the sensing sensitivity of the composite electrode is significantly improved compared to the conventional boron-doped diamond electrode.
[0028] Figure 3 The differential pulse voltammetric response signals of the boron-doped diamond and MOF derivative composite electrode provided by the present invention in a buffer solution (0.1 M PBS, pH = 7.6) with varying dopamine concentrations (0-150 μM). As shown, the peak value of the composite electrode's response signal increases with increasing dopamine concentration.
[0029] Figure 4 This is a fitted curve showing the peak current of the boron-doped diamond and MOF derivative composite electrode provided by the present invention as a function of dopamine concentration. As shown, the peak current of the composite electrode exhibits a clear linear correlation with dopamine concentration, demonstrating the excellent potential of this composite electrode for quantitative measurement of dopamine concentration.
Claims
1. A composite electrode of boron-doped diamond and MOFs derivatives, characterized by: The composite electrode comprises, from bottom to top, a substrate, a boron-doped diamond with nanogrooves on the surface, and a porous metal oxide derived from MOFs.
2. The composite electrode of boron-doped diamond and MOFs derivative according to claim 1, characterized in that: The substrate material is non-metallic silicon, silicon dioxide or metallic titanium, niobium.
3. The composite electrode of boron-doped diamond and MOFs derivative according to claim 1, characterized in that: The boron-doped diamond is prepared by chemical vapor deposition and has a thickness of 5 to 20 μm.
4. The composite electrode of boron-doped diamond and MOFs derivative according to claim 1, characterized in that: The nano-grooves on the surface of the boron-doped diamond are produced by oxygen plasma etching and have a depth of 1 to 2 μm.
5. The composite electrode of boron-doped diamond and MOFs derivative according to claim 1, characterized in that: The MOFs-derived porous metal oxide is prepared by in-situ growth of MOFs on the surface of boron-doped diamond through oxygen plasma etching, and has a height of 0.5-1.5 μm.
6. The method for preparing a composite electrode of boron-doped diamond and MOFs derivatives according to any one of claims 1 to 5, characterized in that: The steps include: (1) Roughen the substrate surface by wet chemical etching or sandblasting; (2) Using ultrasonic method to clean and seed the substrate; (3) Depositing a layer of boron-doped diamond on the surface of the substrate using chemical vapor deposition; (4) Using UV-ozone activation method to improve the hydrophilicity of the boron-doped diamond surface; (5) In situ growth of MOFs on the surface of boron-doped diamond using a solvothermal method; (6) Oxygen plasma etching is used to convert MOFs into porous metal oxides, while nanogrooves are formed on the surface of the underlying boron-doped diamond.
7. The preparation method according to claim 6, characterized in that: The substrate in step (1) is non-metallic silicon, silicon dioxide or metallic titanium, niobium.
8. The preparation method according to claim 6, characterized in that: In step (2), the substrate is ultrasonically cleaned with acetone, anhydrous ethanol, and ultrapure water for 10 minutes respectively; the substrate is then immersed in a suspension containing nano-diamond seed crystals and ultrasonicated for 20 minutes; the nano-diamond seed crystals have a particle size of 5 to 20 nm and a mass fraction of 15% in the suspension.
9. The preparation method according to claim 6, characterized in that: In step (3), methane is used as a carbon source with a volume ratio of 1 to 5%, hydrogen is used as an auxiliary gas with a volume ratio of 95 to 99%, trimethylborane is used as a boron source, the mass concentration of boron in the mixed gas ranges from 6000 to 8000 ppm, the reaction temperature is 450 to 650° C., the reaction time is 5 to 20 h, and a boron-doped diamond film with a thickness of 5 to 20 μm is deposited on a single crystal silicon substrate.
10. The preparation method according to claim 6, characterized in that: Step (5) dissolving the metal salt and the organic ligand in 60 ml of deionized water, then transferring the mixture to a 100 ml polytetrafluoroethylene-based autoclave containing a boron-doped diamond substrate, and heating the mixture at 85-120° C. for 30-120 min; the metal salt is a nitrate, acetate, or chloride of zinc, cobalt, nickel, manganese, aluminum, iron, or copper; the organic ligand is methylimidazole, terephthalic acid, or trimesic acid; and the molar ratio of the metal salt to the organic ligand is 1:1-1:6.