Al3 + and pH dual-mode sensor based on Ln-MOF as well as preparation method and application of Al3 + and pH dual-mode sensor
By synthesizing Ln-MOF on the surface of flexible conductive fibers, high-sensitivity photoelectric dual-mode detection of Al3+ and pH is achieved, solving the problem that the sensor does not respond significantly to low-concentration substances, and expanding the application field of sensors.
Patent Information
- Application Number
- CN202510548773.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-28
- Publication Date
- 2025-08-01
AI Technical Summary
The existing sensors have little response to low-concentration detection substances, have poor detection sensitivity, and have a narrow application range, especially in the wearable field.
Ln-MOF was synthesized on the surface of flexible conductive fibers by a one-pot hydrothermal method to form a photoelectric dual-mode sensor. The carboxyl and amino groups on the surface of the Ln-MOF structure are used as the binding sites of Al3+ and H+ to achieve fluorescence and current responses.
It improves the detection sensitivity and response speed to Al3+ and pH, expands the application range, and is suitable for intelligent wearable, intelligent anti-counterfeiting and environmental monitoring.
Smart Images
Figure CN120404681A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of optoelectronic dual-mode sensing, and specifically relates to a dual-mode sensor based on Ln-MOF for Al 3+ and pH, and a preparation method and application thereof. Background Art
[0002] Metal-organic frameworks (MOFs) are a class of functional materials composed of individual metal ions or metal ion clusters connected together by organic ligand molecules to form extended crystalline frameworks. Luminescent metal-organic frameworks (Ln-MOFs) are an important subclass of MOFs, in which photon emission occurs after absorbing radiation excitation energy. Ln-MOFs have several key advantages compared with other potential luminescent probe materials. The inherent crystallinity of metal-organic frameworks allows for precise structural determination by X-ray diffraction, thus allowing an accurate understanding of atomic positions and interactions that may be involved in analyte detection. In addition, many Ln-MOFs themselves are porous. This porosity brings various advantages to Ln-MOF-based sensors. The porous framework can also be utilized to include analyte-selective guest molecules within the Ln-MOF structure, thus allowing various different sensing mechanisms to occur.
[0003] Currently, many luminescent probes have been developed and widely applied in the fields of medical and health, response to biological and chemical substances, environmental protection, industrial and agricultural production, and national defense security. Although many probes have been studied currently, most probes only detect the information of substances through a single fluorescence reaction. When the concentration of the detected substance is very low, its fluorescence phenomenon may not be so obvious, resulting in a significant reduction in the detection sensitivity. In addition, most sensors are based on fiber membranes, and their applications in the wearable field are still limited to a certain extent. Summary of the Invention
[0004] In view of the technical problems existing in the background art, the present application provides a dual-mode sensor based on Ln-MOF for Al 3+ and pH, and a preparation method and application thereof, aiming to solve the problems of the existing sensors having an unclear reaction to low-concentration detected substances, poor detection sensitivity, and narrow application range.
[0005] In the first aspect, the present application provides a preparation method of a dual-mode sensor based on Ln-MOF for Al 3+ and pH, comprising the following steps:
[0006] S1. Pretreat the fiber substrate;
[0007] S2. Add rare earth metal salts and 2-aminoterephthalic acid into a solvent, and perform ultrasonic treatment to obtain a mixed solution of precursor and ligand;
[0008] S3. Put the fibers processed in step S1 into the mixed solution of the precursor and the ligand, and carry out a hydrothermal reaction to obtain a flexible fiber-based dual-mode sensor with Ln-MOF deposited thereon.
[0009] S4. Wash and dry the flexible fiber-based dual-mode sensor with Ln-MOF deposited thereon to obtain an Al 3+ and pH dual-mode sensor based on Ln-MOF.
[0010] In the technical solution of the embodiment of the present application, a flexible conductive fiber is used as a substrate, and Ln-MOF is synthesized on its surface by a one-pot hydrothermal method to obtain a photoelectric dual-mode sensor that simultaneously responds to Al 3+ and pH. On the one hand, the carboxyl and amino groups on the surface of the Ln-MOF structure can serve as binding sites for Al 3+ and H + to specifically recognize the two ions and produce a fluorescence response; on the other hand, the Ln-MOF is combined with the conductive fiber, enabling the Ln-MOF to produce a significant current response to Al 3+ and H + in an electrochemical analysis system. The Al 3+ and pH dual-mode sensor based on Ln-MOF prepared by the present invention has a simple preparation process, low toxicity, good repeatability, and fast fluorescence response and electrochemical response to Al 3+ and pH, with a low detection limit and high sensitivity, and has good application prospects in the fields of intelligent wearable devices, intelligent anti-counterfeiting, and environmental monitoring.
[0011] In some embodiments, in step S2, the rare earth metal salt is europium nitrate hexahydrate, the solvent is N,N-dimethylformamide, the concentration of the rare earth metal salt in the mixed solution is 0.01 - 0.03 mol / L, and the concentration of 2-aminoterephthalic acid is 0.01 - 0.03 mol / L; the molar ratio of the rare earth metal salt to 2-aminoterephthalic acid is 1 - 3:1 - 3.
[0012] In this embodiment, europium nitrate hexahydrate and 2-aminoterephthalic acid with specific concentrations and ratios are dissolved in a solvent and used as the precursor and the ligand respectively, which can control the particle size of the Eu 3+ -MOF particles within a reasonable range, enabling them to better adhere to the fibers, and the carboxyl and amino groups on the surface of the formed luminescent metal-organic framework structure can serve as binding sites for Al 3+ and H + to specifically recognize the two ions and produce a fluorescence response. When Al 3+ and H +When combined with the carboxyl and amino functional groups on the surface of the MOF metal-organic framework structure, the resistance on the fiber surface will change accordingly, thereby triggering a change in current and generating a current response.
[0013] In some embodiments, in step S3, the temperature of the hydrothermal reaction is 100 - 180 °C, and the time of the hydrothermal reaction is 12 - 48 h.
[0014] In this embodiment, through the hydrothermal reaction, the prepared Eu 3+ -MOF structured luminescent metal-organic framework is uniformly deposited on the conductive fiber substrate, and the particle size and thickness of the Eu 3+ -MOF particles deposited on the fiber substrate are controlled to achieve a better adhesion effect and higher sensitivity.
[0015] In some embodiments, in step S1, the fiber substrate includes at least one of metal fibers, carbon black-based fibers, conductive metal compound fibers, and conductive polymer fibers, and the average diameter of the fiber substrate is 3 - 7 μm.
[0016] In this embodiment, a conductive fiber is selected as the substrate, and the Eu 3+ -MOF structured luminescent metal-organic framework is deposited on its surface. Due to the good conductivity of the conductive fiber, the metal-organic framework of the Eu 3+ -MOF structure can generate a response to the current, and Al 3+ and pH are detected through the electrical response.
[0017] In some embodiments, in step S1, the process of the pretreatment is as follows: the fiber substrate is successively placed in water and an alcohol solution, taken out after ultrasonic oscillation for 10 - 20 min, then rinsed with deionized water and dried to obtain the pretreated fiber substrate.
[0018] In this embodiment, the fiber substrate is ultrasonically treated in water and an alcohol solution to obtain a fiber substrate with a clean surface, preparing for the subsequent deposition of metal framework particles.
[0019] In some embodiments, in step S2, the temperature of the ultrasonic treatment is room temperature, and the time of the ultrasonic treatment is 10 - 30 min.
[0020] In this embodiment, through the ultrasonic treatment, the ligand and the precursor can be fully mixed and contacted to form a metal-organic framework.
[0021] In a second aspect, the embodiments of the present application provide a dual-mode sensor for Al 3+ and pH based on Ln-MOF, using the Al 3+Prepared by the method for preparing a dual-mode sensor for Al and pH, including a flexible conductive fiber substrate and Ln-MOF particles deposited on its surface.
[0022] In the technical solution of the embodiment of the present application, the prepared Ln-MOF-based Al 3+ and pH dual-mode sensor, due to using a conductive fiber as the substrate and depositing Ln-MOF particles on the surface, can detect Al 3+ and pH both through fluorescence signals and current signals.
[0023] In some embodiments, the particle size of the Ln-MOF particles is 1-2 μm, and the deposition thickness is 1-4 μm.
[0024] In this embodiment, by controlling the particle size of the Ln-MOF particles and the deposition thickness on the conductive fiber, the Ln-MOF particles can be deposited more uniformly and densely on the substrate, with better adhesion fastness and better response effect.
[0025] Thirdly, the embodiment of the present application provides an application of a Ln-MOF-based Al 3+ and pH dual-mode sensor. The Ln-MOF-based Al 3+ and pH dual-mode sensor described in claims 8-9 is applied to the fields of intelligent wearable, intelligent anti-counterfeiting and environmental monitoring.
[0026] In the technical solution of the embodiment of the present application, the prepared Ln-MOF-based Al 3+ and pH dual-mode sensor can respond to Al 3+ and pH through fluorescence signals and electrical signals, and uses a flexible conductive fiber as the substrate, which is visual and can be applied to the fields of intelligent wearable, intelligent anti-counterfeiting and environmental monitoring.
[0027] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the description. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the specific embodiments of the present application are hereinafter specifically exemplified. Brief Description of the Drawings
[0028] In order to more clearly illustrate the technical solution of the present application, the drawings used in the present application will be briefly introduced below. Obviously, the following described drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts.
[0029] Figure 1 It is an electron micrograph of the carbon fiber substrate after pretreatment in Example 1.
[0030] Figure 2 Electron micrograph of the dual-mode sensor based on Ln-MOF for Al prepared in Example 1 3+ and pH
[0031] Figure 3 Electron micrograph of the dual-mode sensor based on Ln-MOF for Al prepared in Example 1 3+ and fluorescence sensing diagram of the dual-mode sensor for pH
[0032] Figure 4 Electron micrograph of the dual-mode sensor based on Ln-MOF for Al prepared in Example 1 3+ and electrochemical sensing diagram of the dual-mode sensor for pH
[0033] Figure 5 Electron micrograph of the dual-mode sensor based on Ln-MOF for Al prepared in Example 1 3+ and fluorescence sensing diagrams of the dual-mode sensor after being placed for 1, 10, 30, and 60 days respectively
[0034] Figure 6 Electron micrograph of the dual-mode sensor based on Ln-MOF for Al prepared in Example 1 3+ and electrochemical sensing diagrams of the dual-mode sensor after being placed for 1, 7, 14, and 28 days respectively Detailed implementation mode
[0035] The embodiments of the technical solution of the present application will be described in detail below. The following embodiments are only used to illustrate the technical solution of the present application more clearly, so they are only examples and cannot be used to limit the protection scope of the present application.
[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms "including" and "having" and any variations thereof used herein are only for the purpose of describing specific embodiments and are not intended to limit this application.
[0037] Referring to "embodiment" herein means that the specific features, structures or characteristics described in connection with the embodiment may be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.
[0038] In order to solve the problems that the existing sensors have an unclear reaction to low-concentration detection substances and poor detection sensitivity, the present application provides a kind of Al based on Ln-MOF 3+Dual-mode sensor for Al and pH, its preparation method and application. Using flexible conductive fibers as the substrate, a uniform and dense Ln-MOF layer was polymerized on the surface of the fibers by a one-pot hydrothermal method to obtain a photo-electro dual-mode sensor that simultaneously responds to Al 3+ and pH. On the one hand, the carboxyl and amino groups on the surface of the Ln-MOF structure can serve as the binding sites for Al 3+ and H + , specifically recognize the two ions, and produce a fluorescence response; on the other hand, the Ln-MOF is compounded with the conductive fiber, enabling the Ln-MOF to produce a significant current response to Al 3+ and H + in an electrochemical analysis system. When the detected concentrations of Al 3+ and H + are low and the fluorescence signal is not obvious, the current response is still obvious, which can be used as a good supplement, making the detection limit and sensitivity of the sensor higher. Among them, by regulating the molar ratio of the precursor and the ligand and the reaction parameter conditions, the particle size and deposition amount of the organometallic framework particles deposited on the surface of the conductive fiber can be effectively regulated, so that the organometallic framework particles are uniformly and densely deposited on the fiber substrate with high adhesion strength. Furthermore, the luminescence intensity and stability of the fiber are both good. The fiber-based dual-mode sensor has good flexibility, fast response time, excellent stability and sensitive sensing characteristics. The preparation process of the Al 3+ and pH dual-mode sensor based on Ln-MOF of the present invention is simple, has low toxicity, good flexibility, good repeatability, and has fast fluorescence response and electrochemical response to Al 3+ and pH, low detection limit and high sensitivity, and has good application prospects in the fields of intelligent wearable, intelligent anti-counterfeiting and environmental monitoring.
[0039] On the one hand, the present application provides a preparation method of an Al 3+ and pH dual-mode sensor based on Ln-MOF, comprising the following steps:
[0040] S1. Pretreat the fiber substrate;
[0041] S2. Add rare earth metal salts and 2-aminoterephthalic acid to a solvent, and perform ultrasonic treatment to obtain a mixed solution of precursor and ligand;
[0042] S3. Put the fiber treated in step S1 into the mixed solution of precursor and ligand, and perform a hydrothermal reaction to obtain a flexible fiber-based dual-mode sensor with Ln-MOF deposited;
[0043] S4. Wash and dry the flexible fiber-based dual-mode sensor with Ln-MOF deposited to obtain an Al 3+Dual-mode sensor for Al and pH.
[0044] In the technical solution of the embodiment of the present application, a flexible conductive fiber is used as a substrate, and Ln-MOF is synthesized on its surface by a one-pot hydrothermal method to obtain a photo-electro dual-mode sensor that simultaneously responds to Al 3+ and pH. On the one hand, the carboxyl and amino groups on the surface of the Ln-MOF structure can serve as binding sites for Al 3+ and H + , specifically recognize the two ions, and produce a fluorescence response; on the other hand, the Ln-MOF is compounded with the conductive fiber, so that the Ln-MOF can generate a significant current response to Al 3+ and H + in an electrochemical analysis system. The Al 3+ and pH dual-mode sensor based on Ln-MOF prepared by the present invention has a simple preparation process, low toxicity, good repeatability, and fast fluorescence response and electrochemical response to Al 3+ and pH, with a low detection limit and high sensitivity, and has good application prospects in the fields of intelligent wearable, intelligent anti-counterfeiting, and environmental monitoring.
[0045] Further, in some embodiments, in step S2, the rare earth metal salt is europium nitrate hexahydrate, the solvent is N,N-dimethylformamide, the concentration of the rare earth metal salt in the mixed solution is 0.01 - 0.03 mol / L, and the concentration of 2-aminoterephthalic acid is 0.01 - 0.03 mol / L; the molar ratio of the rare earth metal salt to 2-aminoterephthalic acid is 1 - 3:1 - 3.
[0046] In the technical solution of the embodiment of the present application, europium nitrate hexahydrate and 2-aminoterephthalic acid with specific concentrations and ratios are dissolved in a solvent and used as a precursor and a ligand respectively, which can control the particle size of the obtained Eu 3+ -MOF particles within a reasonable range, enabling them to better adhere to the fiber, and the carboxyl and amino groups on the surface of the formed luminescent metal-organic framework structure can serve as binding sites for Al 3+ and H + , specifically recognize the two ions, and produce a fluorescence response. When Al 3+ and H + bind to the carboxyl and amino functional groups on the surface of the MOF metal-organic framework structure, the resistance on the fiber surface will change accordingly, thereby triggering a change in current and generating a current response.
[0047] In the technical solution of the embodiment of the present application, in some embodiments, in step S3, the temperature of the hydrothermal reaction is 100 - 180 °C, and the time of the hydrothermal reaction is 12 - 48 h.
[0048] In this embodiment, through a hydrothermal reaction, the prepared Eu 3+ -MOF-structured luminescent metal-organic framework is uniformly deposited on the conductive fiber substrate, and the particle size and thickness of the Eu 3+ -MOF particles deposited on the fiber substrate are controlled to achieve a better adhesion effect and higher sensitivity.
[0049] Furthermore, in some embodiments, in step S1, the fiber substrate includes at least one of metal fibers, carbon black-based fibers, conductive metal compound fibers, and conductive polymer fibers, and the average diameter of the fiber substrate is 3 - 7 μm.
[0050] In the technical solution of the embodiment of the present application, a conductive fiber is selected as the substrate, and the Eu 3+ -MOF-structured luminescent metal-organic framework is deposited on its surface. Due to the good conductivity of the conductive fiber, the Eu 3+ -MOF-structured metal-organic framework can respond to the current, and Al 3+ and pH are detected through the electrical response.
[0051] Furthermore, in some embodiments, in step S1, the pretreatment process is as follows: the fiber substrate is successively placed in water and an alcohol solution, taken out after ultrasonic oscillation for 10 - 20 min, then rinsed with deionized water and dried to obtain the pretreated fiber substrate.
[0052] In the technical solution of the embodiment of the present application, the fiber substrate is ultrasonically treated in water and an alcohol solution to obtain a fiber substrate with a clean surface, which prepares for the subsequent deposition of metal framework particles.
[0053] Furthermore, in some embodiments, in step S2, the temperature of the ultrasonic treatment is room temperature, and the time of the ultrasonic treatment is 10 - 30 min.
[0054] In the technical solution of the embodiment of the present application, through ultrasonic treatment, the ligand and the precursor can be fully mixed and contacted to form a metal-organic framework.
[0055] In a second aspect, the embodiment of the present application provides a dual-mode sensor for Al 3+ and pH based on Ln-MOF, which is prepared by using the preparation method of the dual-mode sensor for Al 3+ and pH based on Ln-MOF according to any one of claims 1 - 7, and includes a flexible conductive fiber substrate and Ln-MOF particles deposited on its surface.
[0056] In the technical solution of the embodiment of the present application, the prepared dual-mode sensor for Al 3+A dual-mode sensor for Al and pH, which uses conductive fibers as the substrate and deposits Ln-MOF particles on the surface, can detect Al and pH through both fluorescence signals and current signals. 3+ and pH.
[0057] Furthermore, in some embodiments, the particle size of the Ln-MOF particles is 1-2 μm, and the deposition thickness is 1-4 μm.
[0058] In the technical solution of the embodiment of the present application, by controlling the particle size of the Ln-MOF particles and the deposition thickness on the conductive fiber, the Ln-MOF particles can be deposited on the substrate more uniformly and densely, with better adhesion and better response effect.
[0059] In a third aspect, the embodiment of the present application provides an application of a dual-mode sensor for Al and pH based on Ln-MOF. The dual-mode sensor for Al and pH described in claims 8-9 is applied to the fields of smart wearables, smart anti-counterfeiting, and environmental monitoring. 3+ and pH, 3+ and the dual-mode sensor for pH is applied to the fields of smart wearables, smart anti-counterfeiting, and environmental monitoring.
[0060] In the technical solution of the embodiment of the present application, the prepared dual-mode sensor for Al and pH based on Ln-MOF can respond to Al and pH through fluorescence signals and electrical signals, and uses flexible conductive fibers as the substrate, which is visual and can be applied to the fields of smart wearables, smart anti-counterfeiting, and environmental monitoring. 3+ and pH, 3+ and can respond to Al and pH, and uses flexible conductive fibers as the substrate, which is visual and can be applied to the fields of smart wearables, smart anti-counterfeiting, and environmental monitoring.
[0061] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain the present application and should not be construed as a limitation of the present application. For those not specified in the embodiments, the techniques or conditions described in the literature in the art or according to the product specifications are followed. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.
[0062] Example 1
[0063] This embodiment provides a preparation method for a dual-mode sensor for Al and pH based on Ln-MOF, which specifically includes the following steps: 3+ and pH,
[0064] (1) The carbon fiber with an average diameter of about 5 μm is successively placed in deionized water and ethanol for ultrasonic cleaning for 15 min, dried and stored for later use.
[0065] (2) Weigh 0.2 mmol of europium nitrate hexahydrate and 0.4 mmol of 2-aminoterephthalic acid respectively and add them into 20 mL of N,N-dimethylformamide solvent. Place it in an ultrasonic cleaner and ultrasonicate for 30 min at a power of 300 W to obtain a mixed solution of europium nitrate hexahydrate and 2-aminoterephthalic acid.
[0066] (3) Put the pretreated carbon fiber in step (1) into the mixed solution of europium nitrate hexahydrate and 2-aminoterephthalic acid in step S2, and carry out hydrothermal reaction at 150 °C for 36 h to obtain carbon fiber with Eu 3+ -MOF deposited on its surface.
[0067] (4) Take out the carbon fiber with Eu 3+ -MOF deposited on its surface, wash it successively with N,N-dimethylformamide and ethanol, and then dry it to obtain a carbon fiber-based dual-mode sensor based on Eu 3+ -MOF for Al 3+ and pH.
[0068] Figure 1 This is the electron microscope image of the carbon fiber substrate after being treated by step (1) in this example. Figure 2 This is the electron microscope image of the carbon fiber-based dual-mode sensor based on Eu 3+ -MOF for Al 3+ and pH prepared in this example.
[0069] From Figure 1 and Figure 2 it can be seen that, as can be seen from Figure 1 , after the carbon fiber substrate is cleaned, the fiber surface is a smooth structure. As can be seen from Figure 2 , after the hydrothermal reaction, a thick layer of Eu 3+ -MOF particles grows tightly on the carbon fiber surface. The diameter of the Eu 3+ -MOF particles is 1 - 2 μm, and the deposition thickness is 2 - 4 μm.
[0070] Prepare aqueous solutions of different concentrations of Al 3+ . Weigh 1.33 g of anhydrous aluminum chloride and dissolve it in 10 mL of deionized water to obtain a 1 mol / L Al 3+ solution. Then dilute the 1 mol / L Al3+ solution with deionized water according to a certain ratio respectively to obtain Al 3+ solutions with concentrations of 100 mmol / L, 10 mmol / L, 1 mmol / L, 100 μmol / L, 10 μmol / L, 1 μmol / L, 100 nmol / L, 10 nmol / L, and 1 nmol / L respectively.
[0071] Prepare solutions with different pH values. Measure 0.83 mL of 12 mol / L concentrated hydrochloric acid and add it to 10 mL of deionized water to obtain a solution with a pH of 1. Then, dilute it with deionized water in a certain proportion to obtain solutions with pH values of 2, 3, 4, 5, 6, and 7 respectively.
[0072] Place the carbon fiber-based dual-mode sensor for Al 3+ and pH prepared in this example 3+ in the above-mentioned solutions with different concentrations of Al 3+ and solutions with different pH values respectively, and test their fluorescence sensing performance and electrochemical sensing performance. The test results are shown in Figure 3 and Figure 4 respectively.
[0073] It can be seen from Figure 3 that when the concentration of Al 3+ is in the range of 10 μmol / L to 100 mmol / L and the pH value is in the range of 3 to 7, the prepared carbon fiber-based dual-mode sensor for Al 3+ and pH based on Eu 3+ -MOF has a good fluorescence enhancement effect on Al 3+ and pH. However, when the concentration of Al 3+ and pH is at a lower or higher concentration, the fluorescence enhancement effect is not obvious. It can be seen from Figure 4 that the prepared carbon fiber-based dual-mode sensor for Al 3+ and pH based on Eu 3+ -MOF has good electrochemical detection performance for Al 3+ and pH, and the detection limit is lower than that of fluorescence sensing.
[0074] Place the carbon fiber-based dual-mode sensor for Al 3+ and pH prepared in this example for 1, 10, 30, and 60 days respectively, and then detect the fluorescence sensing performance of Al 3+ at the same concentration. The test results are shown in 3+ and Figure 5 respectively.
[0075] Place the carbon fiber-based dual-mode sensor for Al 3+ and pH prepared in this example for 1, 7, 14, and 28 days respectively, and then detect the electrochemical sensing performance of Al 3+ at the same concentration. The results are shown in 3+ and Figure 6 respectively.
[0076] It can be seen from Figure 5 and Figure 6 that the prepared carbon fiber-based dual-mode sensor for Al3+ Al of -MOF 3+ The carbon fiber-based dual-mode sensor for Al 3+ and pH still has similar fluorescence responses and current responses after being placed for many days, indicating that the prepared carbon fiber-based dual-mode sensor based on Eu 3+ -MOF has good stability for Al
[0077] Examples 2 to 3 and Comparative Examples 1 to 2
[0078] Examples 2 to 3 and Comparative Examples 1 to 2 respectively provide a preparation method of a dual-mode sensor for Al 3+ and pH. Compared with Example 1, the difference lies in that the molar ratio of europium hexahydrate nitrate and 2-aminoterephthalic acid in step (2) is different. The relevant performances of Examples 2 to 3 and Comparative Examples 1 to 2 are tested respectively, as shown in Table 1 specifically. Other steps are substantially the same as those in Example 1 and will not be elaborated here.
[0079] Table 1 Molar ratios of europium hexahydrate nitrate and 2-aminoterephthalic acid and performance test results in Examples 2 to 3 and Comparative Examples 1 to 2
[0080]
[0081] It can be seen from Table 1 that when the molar ratio of europium hexahydrate nitrate and 2-aminoterephthalic acid is 1 to 3:1 to 3, the particle size of the generated MOF particles is appropriate and the deposition effect on the fiber substrate is also good. Excessive or too little amount of europium hexahydrate nitrate will cause the particle size of the MOF particles to decrease, thereby affecting the deposition thickness on the fiber substrate, and further leading to the weakening of fluorescence response and current response performances.
[0082] Examples 4 to 5 and Comparative Examples 3 to 4
[0083] Examples 4 to 5 and Comparative Examples 3 to 4 respectively provide a preparation method of a dual-mode sensor for Al 3+ and pH. Compared with Example 1, the difference lies in that the hydrothermal reaction temperature and time in step (3) are different. The relevant performances of Examples 4 to 5 and Comparative Examples 3 to 4 are tested respectively, as shown in Table 2 below specifically. Other steps are substantially the same as those in Example 1 and will not be elaborated here.
[0084] Table 2 Hydrothermal reaction temperature and time and performance test results in Examples 4 to 5 and Comparative Examples 3 to 4
[0085]
[0086] As can be seen from Table 2, if the hydrothermal reaction temperature is too high or the hydrothermal reaction time is too long, it will lead to too large deposition thickness and particle size of MOF particles, and the adhesion of the particles on the fiber substrate will decrease, resulting in a decline in the fluorescence response and current response effects of the sensor; while if the hydrothermal reaction temperature is too low or the hydrothermal reaction time is too short, it will lead to the MOF particles being out of shape or fewer synthesized particles, thus affecting the fluorescence response and current response effects and causing the sensing performance to decline.
[0087] Comparative Example 5
[0088] This comparative example provides a preparation method of a dual-mode sensor based on Ln-MOF for Al 3+ and pH. Compared with Example 1, the difference lies in that the fiber substrate in step (1) is different. The fiber substrate used in this comparative example is PVA, and the other steps are substantially the same as those in Example 1 and will not be elaborated here.
[0089] The fluorescence sensing performance and current sensing performance of this comparative example were tested, and the results showed that there was no fluorescence and electrochemical sensing performance. This is because the PVA fiber is not conductive and the growth of MOF is uneven.
[0090] In summary, this application provides a dual-mode sensor based on Ln-MOF for Al 3+ and pH, as well as its preparation method and application, belonging to the field of optoelectronic dual-mode sensing technology. Using a flexible conductive fiber as the substrate, Ln-MOF was synthesized on its surface by a one-pot hydrothermal method to obtain an optoelectronic dual-mode sensor that simultaneously responds to Al 3+ and pH. On the one hand, the carboxyl and amino groups on the surface of the Ln-MOF structure can serve as the binding sites for Al 3+ and H + to specifically recognize the two ions and produce a fluorescence response; on the other hand, the composite of Ln-MOF and the conductive fiber enables Ln-MOF to produce a significant current response to Al 3+ and H + in an electrochemical analysis system. The preparation process of the dual-mode sensor based on Ln-MOF for Al 3+ and pH prepared by the present invention is simple, has little toxicity, good repeatability, and has a fast fluorescence response and electrochemical response to Al 3+ and pH, a low detection limit, and high sensitivity, and has good application prospects in the fields of intelligent wearable devices, intelligent anti-counterfeiting, and environmental monitoring.
[0091] It should be noted that this application is not limited to the above embodiments. The above embodiments are only examples, and embodiments having the same composition in essence as the technical idea and achieving the same effect within the scope of the technical solution of this application are all included in the technical scope of this application. In addition, within the scope of not departing from the gist of this application, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways constructed by combining some constituent elements in the embodiments are also included in the scope of this application.
Claims
1. A preparation method of a dual-mode sensor based on Ln-MOF for Al 3+ and pH, characterized in that It includes the following steps: S1. Pretreat the fiber substrate; S2. Add rare earth metal salt and 2-aminoterephthalic acid into a solvent, and perform ultrasonic treatment to obtain a mixed solution of precursor and ligand; S3. Put the fiber treated in step S1 into the mixed solution of precursor and ligand, and perform hydrothermal reaction to obtain a flexible fiber-based dual-mode sensor with Ln-MOF deposited thereon; S4. Wash and dry the flexible fiber-based dual-mode sensor deposited with the Ln-MOF to obtain a dual-mode sensor based on Ln-MOF for Al 3+ and pH.
2. Preparation method of the dual-mode sensor based on Ln-MOF for Al 3+ and pH, characterized in that In step S2, the molar ratio of the rare earth metal salt to 2-aminoterephthalic acid is 1-3:1-3.
3. Preparation method of the dual-mode sensor based on Ln-MOF for Al 3+ and pH, characterized in that In step S2, the rare earth metal salt is europium nitrate hexahydrate, the solvent is N,N-dimethylformamide, the concentration of the rare earth metal salt in the mixed solution is 0.01-0.03 mol / L, and the concentration of 2-aminoterephthalic acid is 0.01-0.03 mol / L.
4. Preparation method of the dual-mode sensor based on Ln-MOF for Al 3+ and pH, characterized in that In step S3, the temperature of the hydrothermal reaction is 100-180 °C, and the time of the hydrothermal reaction is 12-48 h.
5. Preparation method of the dual-mode sensor based on Ln-MOF for Al 3+ and pH, characterized in that In step S1, the fiber substrate includes at least one of metal fiber, carbon black-based fiber, conductive metal compound fiber and conductive polymer fiber, and the average diameter of the fiber substrate is 3-7 μm.
6. Preparation method of a dual-mode sensor based on Ln-MOF for Al 3+ and pH, characterized in that In step S1, the process of the pretreatment is: sequentially place the fiber substrate in water and an alcohol solution, take it out after ultrasonic oscillation for 10-20 min, then rinse it with deionized water and dry it to obtain the pretreated fiber substrate.
7. Preparation method of a dual-mode sensor based on Ln-MOF for Al 3+ and pH, characterized in that In step S2, the temperature of the ultrasonic treatment is room temperature, and the time of the ultrasonic treatment is 10-30 min.
8. A dual-mode sensor based on Ln-MOF for Al 3+ and pH, characterized in that Prepared by the method for preparing a dual-mode sensor based on Ln-MOF according to any one of claims 1 to 7, comprising a flexible conductive fiber substrate and Ln-MOF particles deposited on its surface. 3+ 9. The Ln-MOF-based Al 3+ and pH dual-mode sensor according to claim 8, characterized in that The particle size of the Ln-MOF is 1-2 μm, and the deposited thickness is 1-4 μm.
10. Application of a dual-mode sensor based on Ln-MOF for Al 3+ and pH, characterized in that The dual-mode sensor based on Ln-MOF for Al 3+ and pH described in claims 8 to 9 is applied to the fields of smart wearables, smart anti-counterfeiting, and environmental monitoring.