Boron-doped diamond film heavy metal ion detection electrode and preparation method thereof

Abstract

The invention relates to the field of heavy metal ion detection, in particular to a boron-doped diamond film heavy metal ion detection electrode and a preparation method thereof.The preparation method comprises the following steps that 1, a substrate is selected; step 2, preparing an electrode to obtain a BDD film modified by nano-gold particles; 3, characterizing and testing the electrode; and step 4, microelectrode structure design: after high-performance test electrode parameters are obtained in the step 3, the boron-doped diamond film heavy metal ion detection electrode described in any one of the above is obtained by using the size advantages of the nano material and the boron-doped diamond film. Compared with other heavy metal ion detection electrodes, according to the technical scheme, BDD is stable in chemical property, wide in electrochemical window, stable in property, suitable for various complex environments and wide in working range.

Description

Technical Field

[0001] The invention relates to the field of heavy metal ion detection, and in particular to a boron-doped diamond film heavy metal ion detection electrode and a preparation method thereof. Background Art

[0002] Electrochemical analysis methods are widely used to detect heavy metal ions due to their high sensitivity, simple operation, and portability. Electrochemical analysis is mainly based on a three-electrode system consisting of a working electrode, a reference electrode, and a counter electrode. The working electrode is the core of sensor detection and is the interface for material reaction conversion and signal reception and transmission. Electrochemical analysis modified electrodes generally use mercury film electrodes and glassy carbon electrodes. Since mercury is highly toxic and easily causes environmental pollution, many regions and countries restrict or even prohibit the use of mercury electrodes; the surface of the glassy carbon electrode is easily affected by interfering substances in the solvent, resulting in electrode passivation, reduced reproducibility and sensitivity. In recent years, boron-doped diamond (BDD) electrodes have attracted widespread attention due to their advantages such as wide potential window, low background current, corrosion resistance, stability, and good repeatability.

[0003] However, when gold electrodes are used directly to detect heavy metal ions, the dissolution current signal will be affected by the use of the gold electrode, surface pretreatment and the formation of an oxide film on the surface, which is not conducive to the quantitative detection of heavy metal ions. At present, modifying the electrode surface with nanoparticles can promote the transfer of interfacial electrons, improve the electrochemical dissolution characteristics and ion selectivity of heavy metal ions, and thus improve the detection sensitivity of the electrode. It has become an important method to improve the electrode catalytic efficiency and electrochemical analysis capabilities. However, due to the weak van der Waals force between gold nanoparticles and boron-doped diamond film electrodes, directly modifying BDD electrodes with nanoparticles can easily cause the gold nanoparticles to fall off, affecting the reliability and stability of the electrode.

[0004] Therefore, the existing technology has the problem of poor stability and low sensitivity of heavy metal ion electrodes, which is urgently needed to be solved by those skilled in the art. Summary of the invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a heavy metal ion detection electrode and a preparation method thereof that can solve the problem that a heavy metal ion detection electrode modified with gold nanoparticles has poor binding force with a substrate and is unstable, improve the reliability of the electrode, increase the width of the working range of the electrode, and improve the detection sensitivity.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a boron-doped diamond film heavy metal ion detection electrode, comprising a substrate, a nanosheet, and nanoparticles, wherein the nanosheet and the nanoparticles wrap the substrate, the nanosheet comprises a boron-doped diamond film, a MoS2 nanosheet, and the nanoparticles are gold nanoparticles, the diamond surface atomic dangling bonds of the boron-doped diamond film are covalently bonded to the MoS2 nanosheet, and the MoS2 nanosheet is bonded to the gold nanoparticles by gold-sulfur bonds.

[0007] The boron-doped diamond film heavy metal ion detection electrode is characterized in that the substrate is made of any one of metal niobium, titanium, tantalum, molybdenum or non-metal silicon, and the niobium, titanium, tantalum, molybdenum or silicon is processed into an electrode shape.

[0008] The boron-doped diamond film heavy metal ion detection electrode is characterized in that the boron-doped diamond film and MoS2 particles are deposited step by step on the substrate in a vacuum environment by chemical vapor deposition.

[0009] A method for preparing a boron-doped diamond film heavy metal ion detection electrode comprises the following steps:

[0010] Step 1: Select a substrate, and select any one of metal niobium, titanium, tantalum, molybdenum or non-metal silicon as the initial substrate of the boron-doped diamond thin film electrode;

[0011] Step 2: Electrode preparation: using chemical vapor deposition to deposit boron-doped diamond film and MoS2 nanosheets in a vacuum environment to obtain a growth electrode on the initial substrate, and immersing the growth electrode in a gold nanoparticle solution to obtain a BDD film modified with nano-gold particles;

[0012] Step 3: Electrode characterization and testing: X-ray photoelectron spectrometer and scanning electron microscope were used to analyze the surface of BDD film modified with gold nanoparticles, growth parameters were adjusted, different modified electrodes were prepared, and cyclic voltammetry characteristics were used to characterize the oxidation and reduction characteristics in the electrochemical reaction;

[0013] Step 4: Microelectrode structure design. After obtaining the high-performance test electrode parameters through step 3, the size advantages of nanomaterials and boron-doped diamond films are utilized to obtain a boron-doped diamond film heavy metal ion detection electrode as described in any of the above items.

[0014] In the above-mentioned method for preparing the boron-doped diamond film heavy metal ion detection electrode, in step 1, metal niobium, titanium, tantalum, molybdenum or non-metal silicon is processed into a micro size or electrode shape as an initial substrate.

[0015] The method for preparing the boron-doped diamond film heavy metal ion detection electrode, step 2 comprises:

[0016] Step 2-1: using processed metal niobium, titanium, tantalum, molybdenum or non-metal silicon as an initial substrate, using a diamond nano seed solution to prepare a boron-doped diamond film in an atmosphere of borane, methane and hydrogen to obtain a diamond substrate;

[0017] Step 2-2: On the basis of the diamond substrate, MoS2 nanosheets are grown using MoO3 and S as sources, and the dangling bonds of the diamond surface atoms are covalently bonded with the MoS2 nanosheets to obtain a grown electrode;

[0018] Step 2-3: Soak the grown electrode in the gold nanoparticle solution prepared by the Frens method for 5 hours and blow dry with nitrogen gas to firmly bond the gold nanoparticles to the boron-doped diamond electrode.

[0019] In the above method for preparing the boron-doped diamond thin film heavy metal ion detection electrode, in step 3, the growth parameters include chemical vapor deposition growth conditions, gold nanoparticle size, and preparation conditions.

[0020] In the preparation method of the boron-doped diamond thin film heavy metal ion detection electrode, when performing cyclic voltammetric characterization in step 3, an electrochemical workstation is used to measure the cyclic voltammetric characteristics of the boron-doped diamond electrode modified with nano-gold particles in single and mixed solutions of heavy metal ions.

[0021] The beneficial effects of the boron-doped diamond film heavy metal ion detection electrode and the preparation method thereof of the present invention are as follows: the technical solution modifies MoS2 on the surface of the BDD film, and utilizes the gold-sulfur bond and Coulomb force between MoS2 and Au nanoparticles to modify gold nanoparticles on MoS2-BDD to obtain an Au / MoS2 / BDD electrode. The electrode combines the excellent electrochemical performance of gold nanoparticle-MoS2 in heavy metal ion detection and the stability of the BDD electrode to perform trace detection of heavy metal ions in harsh environments.

[0022] In this technical solution, the gold nanoparticles and MoS2 have a strong gold-sulfur bond, and MoS2 is covalently bonded to the BDD electrode, resulting in high electrode reliability.

[0023] Compared with other heavy metal ion detection electrodes, the BDD of this technical solution has stable chemical properties, a wide electrochemical window, stable properties, is suitable for a variety of complex environments, and has a wide working range.

[0024] In this technical solution, the large specific surface area, good electrochemical properties and catalytic activity of MoS2 nanosheets and gold nanoparticles are combined, the detection sensitivity is high and it is applicable to a variety of heavy metal ions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1Schematic diagram of the morphology of MoS2 deposited at 600-650°C on the surface of the BDD film in an embodiment of the present invention;

[0026] Figure 2 This is an example diagram of preparing AuNPs of different particle sizes on MoS2 by reduction method in an embodiment of the present invention;

[0027] Figure 3 This is a structural diagram of a heavy metal ion detection electrode prepared in an embodiment of the present invention;

[0028] Figure 4 The graphs are the detection results of copper ions under different pH conditions for the boron-doped thin film electrode prepared in the embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is described below in conjunction with specific implementation methods and drawings.

[0030] Example 1

[0031] like Figure 1-Figure 4 As shown, a boron-doped diamond film heavy metal ion detection electrode includes a substrate 4, nanosheets, and nanoparticles. The nanosheets and nanoparticles are wrapped around the outside of the substrate. The nanosheets include a boron-doped diamond film 3 and a MoS2 nanosheet 2. The nanoparticles are gold nanoparticles 1. The diamond surface atoms of the boron-doped diamond film are covalently bonded to the MoS2 nanosheets through dangling bonds, and the MoS2 nanosheets are bonded to the gold nanoparticles through gold-sulfur bonds.

[0032] The substrate uses metals such as niobium, titanium, tantalum, molybdenum, etc. or non-metal silicon, and the metals such as niobium, titanium, tantalum, molybdenum, etc. or silicon are processed into an electrode shape.

[0033] Through the above substrate selection, the selectivity of the substrate can be increased. Metals have excellent electrical conductivity. Niobium and tantalum are resistant to high temperatures but are expensive. Other substrate selections are conducive to reducing costs.

[0034] Boron-doped diamond films and MoS2 nanosheets were deposited on the substrate step by step using chemical vapor deposition in a vacuum environment.

[0035] This embodiment uses MoS2 in MoS2 nanosheets as a modified transition layer. MoS2 is a graphene-like material with a sandwich layered structure. Large-area nanosheets or two-dimensional films can be prepared by chemical vapor deposition. MoS2 exhibits excellent electrochemical sensing performance due to its large surface area, good electron mobility and high electron state density. MoS2 is modified on the surface of the BDD film, and the gold nanoparticles are modified on MoS2-BDD using the gold-sulfur bond and Coulomb force between MoS2 and Au nanoparticles to obtain Au / MoS2 / BDD electrodes. This electrode will combine the excellent electrochemical performance of gold nanoparticles-MoS2 in heavy metal ion detection and the stability of BDD electrodes to perform trace detection of heavy metal ions in harsh environments. The size advantage of nanomaterials is conducive to the development of high-performance portable heavy metal ion detection equipment, and provides new research ideas for the preparation of electrodes, structural design, and reliability sensitivity improvement for electrochemical analysis of heavy metal ions.

[0036] Example 2

[0037] A method for preparing a boron-doped diamond film heavy metal ion detection electrode comprises the following steps.

[0038] Step 1: Select a substrate. Select metals such as niobium, titanium, tantalum, molybdenum, or silicon as the initial substrate for the boron-doped diamond thin film electrode. Use processing tools to process niobium, titanium, tantalum, molybdenum, or silicon into various required shapes such as micro-size or electrode shape as the initial substrate.

[0039] Step 2: Electrode preparation: Boron-doped diamond film and MoS2 particles are deposited step by step on the initial substrate by chemical vapor deposition in a vacuum environment to obtain a grown electrode, and the grown electrode is immersed in a gold nanoparticle solution to obtain a BDD film modified with nano-gold particles.

[0040] include:

[0041] Step 2-1: Use processed niobium, titanium, tantalum, molybdenum or other metals or silicon as the initial substrate, use diamond nano seed solution to prepare boron-doped diamond film in an atmosphere of borane, methane and hydrogen, and obtain a diamond substrate.

[0042] Step 2-2: On the basis of the diamond substrate, MoS2 nanosheets are grown using MoO3 and S as sources. The dangling bonds of the diamond surface atoms are covalently bonded to the MoS2 nanosheets to obtain a grown electrode.

[0043] Step 2-3: Soak the grown electrode in the gold nanoparticle solution prepared by the Frens method for 5 hours and blow dry with nitrogen gas to firmly bond the gold nanoparticles to the boron-doped diamond electrode.

[0044] Figure 2AuNPs were prepared on MoS2 by the reduction method with a particle size of 20-50nm.

[0045] Step 3: Electrode characterization and testing: Use X-ray photoelectron spectrometer and scanning electron microscope to analyze the surface of BDD film after gold particle modification, adjust the growth parameters, prepare different modified electrodes, and use cyclic voltammetry characteristics to characterize the oxidation and reduction characteristics in the electrochemical reaction.

[0046] Growth parameters include chemical vapor deposition growth conditions, gold nanoparticle size, preparation conditions and other adjustment parameters used in the growth process.

[0047] When characterizing the cyclic voltammetric characteristics, an electrochemical workstation was used to measure the cyclic voltammetric characteristics of the boron-doped diamond electrode modified with nano-gold particles in single and mixed solutions of heavy metal ions.

[0048] Step 4: Microelectrode structure design. After obtaining the high-performance test electrode parameters through step 3, the size advantages of nanomaterials and boron-doped diamond films can be used to obtain the boron-doped diamond film heavy metal ion detection electrode recorded in Example 1.

[0049] Through step 4, the detection electrode can be proportionally reduced to make a microelectrode for easy use.

[0050] Example 3

[0051] A method for preparing a boron-doped diamond film heavy metal ion detection electrode.

[0052] 1. Substrate selection.

[0053] Boron-doped diamond thin film electrodes based on metals such as niobium, titanium, tantalum, molybdenum or silicon are used to replace glassy carbon electrodes. Boron-doped diamond electrodes have stable chemical properties, wide electrochemical windows, and can increase electron transmission by adjusting the amount of boron doping. They are ideal electrodes for heavy metal ion detection.

[0054] 2. Electrode preparation.

[0055] The boron-doped diamond film and MoS2 nanosheets are deposited step by step in a vacuum environment by chemical vapor deposition. Metals such as niobium, titanium, tantalum, molybdenum or silicon are selected as substrates. The substrates can be processed into micro-sizes or various shapes. Diamond nano seed solution is used as the substrate to prepare boron-doped diamond films in an atmosphere of borane, methane and hydrogen. The boron doping amount is 6000-10000ppm and the film thickness is 5-10um. The grown boron-doped diamond film is then used as the substrate, and MoO3 and S are used as sources to grow MoS2 nanosheets. The growth temperature is 600-650℃. The atomic dangling bonds on the diamond surface are covalently bonded to the MoS2 nanosheets. The grown electrode is immersed in the gold nanoparticle solution prepared by the Frens method for 5 hours and blown dry with nitrogen. Due to the strong binding force between MoS2 and the gold nanoparticles' gold-sulfur bonds, the gold nanoparticles can be firmly bonded to the boron-doped diamond electrode.

[0056] 3. Electrode characterization and testing.

[0057] The surface of the prepared BDD film modified with nano-gold particles was analyzed by X-ray photoelectron spectrometer and scanning electron microscope, respectively, to analyze the morphology, thickness, size, etc. of the BDD film and nano-gold particles. Different modified electrodes were prepared by changing the chemical vapor deposition growth conditions, the size of gold nanoparticles, the preparation conditions, etc. The cyclic voltammetric characteristics can well characterize the oxidation and reduction characteristics in the electrochemical reaction. Therefore, the cyclic voltammetric characteristics of the boron-doped diamond electrode modified with nano-gold particles in single and mixed solutions of heavy metal ions such as Hg, Cd, As, and Cr can be determined by an electrochemical workstation.

[0058] 4. Microelectrode structure design.

[0059] By utilizing the nano-effect of gold nanoparticles and MoS2 nanosheets, their large specific surface area, good electrochemical properties, electron mobility and catalytic activity, the sensitivity of heavy metal ion detection can be improved. After obtaining high-performance test electrode parameters, the size advantages of nanomaterials and boron-doped diamond films can be used to design microstructured detection electrodes and reduce the volume of heavy metal ion equipment.

[0060] like Figure 4 As shown, taking Cu ion detection as an example, the figure shows the Cu ion detection results of the heavy metal ion detection electrode under different pH conditions. It can be seen that the electrode has an obvious response signal to Cu ions, and the signal is strongest when pH = 3.6.

[0061] The above embodiments are only for illustrating the inventive concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made based on the essence of the content of the present invention should be included in the protection scope of the present invention.

Claims

1. A boron-doped diamond film heavy metal ion detection electrode, characterized in that: The invention comprises a substrate, nanosheets and nanoparticles, wherein the nanosheets and the nanoparticles wrap the substrate, the nanosheets comprise a boron-doped diamond film and a MoS2 nanosheet, the nanoparticles are gold nanoparticles, the diamond surface atomic dangling bonds of the boron-doped diamond film are covalently bonded to the MoS2 nanosheets, and the MoS2 nanosheets are bonded to the gold nanoparticles via gold-sulfur bonds.

2. The boron-doped diamond thin film heavy metal ion detection electrode according to claim 1, characterized in that: The substrate is made of any one of metal niobium, titanium, tantalum, molybdenum or non-metal silicon, and niobium, titanium, tantalum, molybdenum or silicon is processed into an electrode shape.

3. The boron-doped diamond thin film heavy metal ion detection electrode according to claim 1, characterized in that: The boron-doped diamond film and MoS2 particles are deposited step by step on the substrate in a vacuum environment by chemical vapor deposition.

4. A method for preparing a boron-doped diamond film heavy metal ion detection electrode, characterized in that: The following steps are involved: Step 1: Select a substrate, and select any one of metal niobium, titanium, tantalum, molybdenum or non-metal silicon as the initial substrate of the boron-doped diamond thin film electrode; Step 2: Electrode preparation: using chemical vapor deposition to deposit boron-doped diamond film and MoS2 nanosheets in a vacuum environment step by step, obtaining a growth electrode on the initial substrate, and immersing the growth electrode in a gold nanoparticle solution to obtain a BDD film modified with nano-gold particles; Step 3: Electrode characterization and testing: X-ray photoelectron spectrometer and scanning electron microscope were used to analyze the surface of BDD film modified with gold nanoparticles, growth parameters were adjusted, different modified electrodes were prepared, and cyclic voltammetry characteristics were used to characterize the oxidation and reduction characteristics in the electrochemical reaction; Step 4: Microelectrode structure design. After obtaining the high-performance test electrode parameters through step 3, the size advantages of nanomaterials and boron-doped diamond films are utilized to obtain the boron-doped diamond film heavy metal ion detection electrode as described in any one of claims 1-3.

5. The method for preparing the boron-doped diamond thin film heavy metal ion detection electrode according to claim 4, characterized in that: In the step 1, metal niobium, titanium, tantalum, molybdenum or non-metal silicon is processed into micro-size or electrode shape as an initial substrate.

6. The method for preparing a boron-doped diamond thin film heavy metal ion detection electrode according to claim 4, characterized in that: The step 2 comprises: Step 2-1: using processed metal niobium, titanium, tantalum, molybdenum or non-metal silicon as an initial substrate, using a diamond nano seed solution to prepare a boron-doped diamond film in an atmosphere of borane, methane and hydrogen to obtain a diamond substrate; Step 2-2: On the basis of the diamond substrate, MoS2 nanosheets are grown using MoO3 and S as sources, and the dangling bonds of the diamond surface atoms are covalently bonded with the MoS2 nanosheets to obtain a grown electrode; Step 2-3: Soak the grown electrode in the gold nanoparticle solution prepared by the Frens method for 5 hours and blow dry with nitrogen gas to firmly bond the gold nanoparticles to the boron-doped diamond electrode.

7. The method for preparing a boron-doped diamond thin film heavy metal ion detection electrode according to claim 4, characterized in that: In step 3, the growth parameters include chemical vapor deposition growth conditions, gold nanoparticle size, and preparation conditions.

8. The method for preparing a boron-doped diamond thin film heavy metal ion detection electrode according to claim 4, characterized in that: When performing cyclic voltammetric characterization in step 3, an electrochemical workstation is used to measure the cyclic voltammetric characteristics of the boron-doped diamond electrode modified with nano-gold particles in single and mixed solutions of heavy metal ions.

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