Construction method of functionalized MXene electrochemical sensor

Abstract

The invention discloses a construction method of a functionalized MXene electrochemical sensor, and relates to the technical field of electrochemical sensors, and the construction method specifically comprises the following steps: S1, using an MXene nanosheet as a precursor, modifying the surface of the MXene nanosheet with an alkaline functional group, and establishing strong interaction between the alkaline functional group and a PFOS sulfo group; and S2, carrying out intercalation assembly on the MXene composite material by utilizing electrostatic interaction, namely introducing a metal organic framework material between MXene nanosheet layers. The electrode has higher conductivity and high specific surface area, the electrochemical oxidation performance of PFOS can be effectively improved, the detection efficiency and the detection precision are further improved, in addition, the detection cost is lower, the actual application effect is more ideal, and the problems that a diamond electrode is lower in conductivity and an electrode with a high specific surface area is difficult to construct are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical sensors, and in particular to a method for constructing a functionalized MXene electrochemical sensor. Background Art

[0002] Water pollution is one of the most serious threats to human health and safety worldwide. Among them, the persistent organic pollutant perfluorooctane sulfonic acid (PFOS) is distributed all over the world, threatening human health. PFOS can accumulate in human blood and cause reproductive toxicity, developmental toxicity and other hazards to the human body as the accumulation deepens. In addition, because the carbon-fluorine bond is the strongest single bond in organic chemistry, PFOS has excellent stability.

[0003] At present, the commercial method used for detecting PFOS is mainly EPA-3500c, which uses microwave extraction combined with mass spectrometry detection. However, the test cost is expensive and the detection cycle is long. To solve the above problems, technicians in this field have successfully used diamond electrodes to electrochemically oxidize PFOS. The surface of the diamond electrode can produce hydroxyl radicals to attack PFOS, thereby achieving electrochemical oxidation of PFOS. However, diamond electrodes have low electrical conductivity and it is difficult to construct electrodes with high specific surface area, which limits the electrochemical oxidation performance of PFOS. The actual application effect is still not ideal.

[0004] In this regard, technicians in this field thought of using MXene as a precursor to construct electrochemical sensors with good performance. It should be noted that MXene is a new type of two-dimensional composite material with a good specific surface area, but in the field of electrochemical testing, the preparation of electrochemical sensors based on functionalized MXene catalytic materials is still in its infancy.

[0005] Therefore, it is necessary to invent a method for constructing functionalized MXene electrochemical sensors to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide a method for constructing a functionalized MXene electrochemical sensor, by modifying the surface of MXene nanosheets with basic functional groups, and assembling MXene composite materials by electrostatic intercalation, and finally designing a porous structure dominated by micropores and mesopores on the surface of MXene nanosheets, so as to establish a strong interaction between the basic functional groups and the PFOS sulfonic groups, and at the same time, by utilizing the steric hindrance effect, establish different affinities between the functionalized MXene electrochemical sensor and PFOS and other interferents, thereby achieving selective electrochemical detection. In addition, MOF and Cr-MI The directional affinity of the L-101 metal site for the sulfonic group and the CF bond in PFOS further strengthens the strong interaction between the functionalized MXene electrochemical sensor and PFOS to increase the directional capture PFOS capability of the functionalized MXene electrochemical sensor. Finally, the construction of lateral electron transport channels is used to provide good conditions for electron conduction, while the construction of longitudinal ion transport can transform lateral ion transport into short-range vertical ion transport, shorten the transport ion pathway and amplify the mass transfer capacity to accelerate ion transfer, so as to solve the problems of low conductivity and difficulty in constructing high specific surface area electrodes raised in the above-mentioned background technology, which limits the electrochemical oxidation performance of PFOS and the practical application effect is still not ideal.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for constructing a functionalized MXene electrochemical sensor, specifically comprising the following steps:

[0008] S1. Using MXene nanosheets as precursors, modifying the surface of MXene nanosheets with basic functional groups, and establishing strong interactions between the basic functional groups and the sulfonic groups of PFOS;

[0009] S2, using electrostatic intercalation to assemble MXene composite materials, that is, introducing metal organic framework materials between MXene nanosheets, and completing the self-assembly of metal organic framework materials and MXene nanosheets through electrostatic repulsion;

[0010] S3. By regulating the surface functional groups of MXene composite materials, a porous structure dominated by micropores and mesopores is designed on the surface of MXene nanosheets to construct a fast ion / electron transmission channel;

[0011] S4. Prepare functionalized MXene electrochemical sensor.

[0012] Preferably, the surface modification method of the MXene nanosheets in S1 includes covalent modification.

[0013] Preferably, the surface modification method of the MXene nanosheets in S1 also includes self-assembly.

[0014] Preferably, the surface modification method of the MXene nanosheets in S1 also includes ion adsorption.

[0015] Preferably, the basic functional group in S1 includes a guanidine group.

[0016] Preferably, the basic functional group in S1 further includes an amino group.

[0017] Preferably, the basic functional group in S1 further includes a primary amine group.

[0018] Preferably, the basic functional group in S1 further includes a secondary amine group.

[0019] Preferably, the basic functional group in S1 further includes a quaternary amine group.

[0020] Preferably, the metal organic framework material in S2 includes MOF and Cr-M I L-101.

[0021] Technical effects and advantages of the present invention:

[0022] The present invention modifies the surface of MXene nanosheets with basic functional groups, and utilizes electrostatic intercalation to assemble MXene composite materials. Finally, a porous structure dominated by micropores and mesopores is designed on the surface of MXene nanosheets, so as to establish a strong interaction between the basic functional groups and the PFOS sulfonate groups. At the same time, the steric hindrance effect is utilized to establish different affinities between the functionalized MXene electrochemical sensor and PFOS and other interferents, thereby achieving selective electrochemical detection. In addition, MOF and Cr-MI The directional affinity of the L-101 metal site for the sulfonic group and the CF bond in PFOS further strengthens the strong interaction between the functionalized MXene electrochemical sensor and PFOS, so as to increase the directional capture PFOS capability of the functionalized MXene electrochemical sensor. Finally, the construction of the lateral electron transport channel is used to provide good conditions for electron conduction, while the construction of the longitudinal ion transport can transform the lateral ion transport into short-range vertical ion transport, shorten the transport ion pathway and amplify the mass transfer capacity to accelerate ion transfer. In summary, compared with the same type of detection method in the prior art, the present invention has higher conductivity and high specific surface area, can effectively improve the electrochemical oxidation performance for PFOS, thereby improving the detection efficiency and detection accuracy, and also has lower detection cost, and the actual application effect is more ideal. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall process structure of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The present invention provides Figure 1 A method for constructing a functionalized MXene electrochemical sensor is shown, comprising the following steps:

[0026] S1. Using MXene nanosheets as precursors, modifying the surface of MXene nanosheets with basic functional groups, and establishing strong interactions between the basic functional groups and the sulfonic groups of PFOS;

[0027] Specifically, in view of the unique physical and chemical properties of PFOS containing sulfonic groups and CF bonds, basic functional groups such as guanidine groups, amino groups, primary amine groups, secondary amine groups and quaternary amine groups are selected to carry out directionally modified MXene nanosheets through covalent modification, self-assembly and ion adsorption, and then different types of basic functional groups are modified on the surface of MXene nanosheets;

[0028] In the actual detection process, the guanidine group can establish a strong interaction with the sulfonic group through hydrogen bonds, ionic bonds and van der Waals forces. By modifying the basic functional groups such as primary amine groups, secondary amine groups and quaternary amine groups, the steric hindrance effect can be used to establish different affinities between the functionalized MXene electrochemical sensor and PFOS and other interferents, thereby achieving selective electrochemical detection.

[0029] When extended to the control of non-electrical variables, this modification method can be used for the detection and control of other non-electrical variables. For example, replacing the basic functional group with a functional group suitable for detecting specific chemicals can be used to monitor the chemical concentration in the environment and then adjust the amount of chemicals in the environmental control system;

[0030] S2, using electrostatic intercalation to assemble MXene composite materials, that is, introducing metal organic framework materials between MXene nanosheets, and completing the self-assembly of metal organic framework materials and MXene nanosheets through electrostatic repulsion;

[0031] Specifically, after the introduction of MOF and Cr-M I L-101, a strong interaction between the functionalized MXene electrochemical sensor and PFOS was established through the directional affinity of the metal sites of MOF and Cr-M I L-101 for the sulfonic group and the CF bond, thereby increasing the directional capture capability of the functionalized MXene electrochemical sensor for PFOS.

[0032] When extended to non-electrical variable control, the method can be extended to monitor and enhance control regulation, such as pressure or gas concentration. By selecting suitable metal organic framework materials, the detection of specific liquid components can be achieved, and the detection results can be used for PFOS contaminant detection in real-time water treatment systems;

[0033] S3. By regulating the surface functional groups of MXene composite materials, a porous structure dominated by micropores and mesopores is designed on the surface of MXene nanosheets to construct a fast ion / electron transmission channel;

[0034] Specifically, it includes the construction of a lateral electron transport channel, that is, on the basis of introducing basic functional groups in the above steps, tuning the van der Waals forces between MXene nanosheet layers, optimizing the surface of MXene nanosheets, and providing good conditions for electron conduction;

[0035] It also includes the construction of longitudinal ion transport, that is, the introduction of a vertical pore structure. The specific method of introducing the vertical pore structure is: adding a structural directing agent during the MXene nanosheet pore formation process. The introduction of the vertical pore structure can transform lateral ion transport into short-range vertical ion transport, shorten the ion transport pathway and amplify the mass transfer capacity to accelerate ion transfer.

[0036] When extended to non-electrical variable control, this method can be used to regulate other physical variables, such as heat or pressure. In thermal management systems, microporous structures can optimize heat transfer and thus regulate temperature. In pressure regulation systems, the design of pore structures can help control the flow pressure of gases or liquids.

[0037] S4. Prepare functionalized MXene electrochemical sensor.

[0038] The application scenario of the present invention is the control in the sewage treatment system, wherein, by detecting and feeding back the chemical substances (such as PFOS) in the sewage, the operating parameters of the sewage treatment equipment can be adjusted in real time, such as adjusting the dosage, aeration intensity, etc., to achieve the best treatment effect. The relevant sensors can be designed according to the above mass transfer model and sensor structure to detect and adjust the water quality system. Through the above methods and formulas, the non-electrical variables can be accurately controlled and adjusted to ensure the stable operation of the system and improve efficiency.

[0039] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for constructing a functionalized MXene electrochemical sensor, characterized in that: The specific steps include: S1. Using MXene nanosheets as precursors, modifying the surface of MXene nanosheets with basic functional groups, and establishing strong interactions between the basic functional groups and the sulfonic groups of PFOS; S2, using electrostatic intercalation to assemble MXene composite materials, that is, introducing metal organic framework materials between MXene nanosheets, and completing the self-assembly of metal organic framework materials and MXene nanosheets through electrostatic repulsion; S3. By regulating the surface functional groups of MXene composite materials, a porous structure dominated by micropores and mesopores is designed on the surface of MXene nanosheets to construct a fast ion / electron transmission channel; S4. Prepare functionalized MXene electrochemical sensor.

2. The method for constructing a functionalized MXene electrochemical sensor according to claim 1, characterized in that: The surface modification method of the MXene nanosheets in S1 includes covalent modification.

3. The method for constructing a functionalized MXene electrochemical sensor according to claim 2, characterized in that: The surface modification method of the MXene nanosheets in S1 also includes self-assembly.

4. The method for constructing a functionalized MXene electrochemical sensor according to claim 3, characterized in that: The surface modification method of the MXene nanosheets in S1 also includes ion adsorption.

5. The method for constructing a functionalized MXene electrochemical sensor according to claim 4, characterized in that: The basic functional group in S1 includes a guanidine group.

6. The method for constructing a functionalized MXene electrochemical sensor according to claim 5, characterized in that: The basic functional group in S1 also includes an amino group.

7. The method for constructing a functionalized MXene electrochemical sensor according to claim 6, characterized in that: The basic functional group in S1 also includes a primary amine group.

8. The method for constructing a functionalized MXene electrochemical sensor according to claim 7, characterized in that: The basic functional group in S1 also includes a secondary amine group.

9. The method for constructing a functionalized MXene electrochemical sensor according to claim 8, characterized in that: The basic functional group in S1 also includes a quaternary amine group.

10. The method for constructing a functionalized MXene electrochemical sensor according to claim 9, characterized in that: The metal organic framework material in S2 includes MOF and Cr-MIL-101.

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