A hexagonal pyramidal In@CN material and its application

Abstract

The present invention discloses a hexagonal pyramidal In@CN material and its application. The hexagonal pyramidal In@CN material is derived from organic frameworks (MOFs). The In@CN modified electrode is prepared by calcining In-MIL-68 at high temperature in a tubular furnace with nitrogen gas. The performance of the electrode in detecting hydrogen peroxide is then measured using a three-electrode electrochemical workstation and electrochemical detection methods such as cyclic voltammetry. The preparation method of the present invention is simple, low-cost, and has a low environmental pollution index. The prepared In@CN modified electrode material can achieve rapid, sensitive, and highly selective electrochemical detection of hydrogen peroxide, and has potential application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical analysis, and in particular relates to a hexagonal pyramidal In@CN material and applications thereof. Background Art

[0002] Hydrogen peroxide (H2O2) is a common chemical with important applications in many areas of life. Vast quantities of H2O2 are produced worldwide daily to meet demand in various sectors, including healthcare and the chemical industry. H2O2 has bactericidal and bleaching properties and is easily decomposed, making it commonly used in industries such as food processing and chemical production. Furthermore, H2O2 can be used to produce inorganic and organic peroxides. While H2O2 plays many positive roles in real life, its negative effects cannot be ignored. For example, inhaling high concentrations of H2O2 can easily damage the respiratory tract, induce cardiovascular disease, and cancer, negatively impacting human health. Furthermore, the environmental impact of H2O2 emissions is also significant. Excessive H2O2 released into rivers can affect the health of aquatic life and disrupt ecological balance. Furthermore, as a strong oxidant, H2O2 can react with combustibles to release large amounts of heat and oxygen, potentially causing explosions. High concentrations of H2O2 can also cause meteorological explosions if ignited, making preventive monitoring of H2O2 in the air essential. With the development of science and technology, in order to reduce hidden dangers to human safety, many factories are now equipped with H2O2 content detection devices.

[0003] Today, hydrogen peroxide detection plays a vital role in many industrial processes and clinical diagnostics, leading researchers to develop efficient methods for hydrogen peroxide detection. With the advancement of science and technology, researchers have developed a variety of detection methods based on diverse principles. Currently available detection methods include chemical titration, chromatography, spectrophotometry, colorimetry, chemiluminescence, fluorescence, surface-enhanced Raman scattering, and electrochemical methods. Although these various detection methods are constantly evolving to meet practical detection needs, many suffer from drawbacks such as high cost, operational difficulties, and significant inconvenience in practical application, remaining unsatisfactory. With the advancement of research, electrochemical sensors, due to their rapid detection and high sensitivity, are now widely used for the detection of gases such as sulfur dioxide, oxygen, and nitrogen dioxide. Currently, researchers both domestically and internationally are focusing on developing various electrochemical sensors for the detection of hydrogen peroxide. Based on this, the present invention designs and synthesizes modified electrode materials with excellent performance for the electrochemical detection of hydrogen peroxide, thereby producing a high-performance electrochemical sensor. Summary of the Invention

[0004] In response to the current technical problems of low detection sensitivity and high development cost in traditional H2O2 detection, the present invention provides a hexagonal pyramidal In@CN material. The hexagonal pyramidal In@CN material is prepared by pyrolysis of In-MIL-68. The modified electrode prepared by the material has shown excellent performance in the application research of H2O2 electrochemical sensing.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A hexagonal pyramidal In@CN material is prepared by the following steps:

[0007] Step 1: adding indium (III) nitrate hydrate and terephthalic acid to N,N-dimethylformamide, stirring and dissolving, and ultrasonically dispersing to obtain a mixed solution; the amount ratio of indium (III) nitrate hydrate, terephthalic acid and N,N-dimethylformamide is 0.2 mmol:0.4 mmol:40 mL; and the ultrasonic time is 30-60 min;

[0008] Step 2: heating the mixed solution in an oil bath at a temperature of 100-120° C. for 30-60 min.

[0009] Step 3, centrifuging the heated solution in step 2 at 9000 rpm / min for 5 min using a high-speed centrifuge, and washing with anhydrous ethanol three times;

[0010] Step 4: After centrifugation, the mixture was dried in a vacuum drying oven at 70°C for 12 h to obtain In-MIL-68 material;

[0011] Step 5: Pour the In-MIL-68 material into a porcelain boat, then place it in a tubular furnace filled with nitrogen and calcine it. After cooling naturally to room temperature, take it out to obtain the In@CN material. The calcination conditions are 500 °C for 2 h, and heat it to 500 °C at a rate of 5 °C·min-1.

[0012] Application of the above hexagonal pyramidal In@CN material in the detection of hydrogen peroxide.

[0013] Furthermore, the application adopts the following steps:

[0014] Step 1: Weigh In@CN in a centrifuge tube, add ethanol, deionized water, and Nafion solution, mix well, and then ultrasonicate for 10 minutes to obtain an In@CN suspension. For every 2.5 mg of In@CN, the amounts of ethanol, deionized water, and Nafion solution used are 400 μL, 75 μL, and 25 μL, respectively.

[0015] Step 2: Pipette 5 μL of In@CN suspension and evenly apply it on the bare glassy carbon electrode. After the solvent evaporates and solidifies into a film, add more drops. Repeat the operation ten times to obtain the In@CN modified electrode.

[0016] In step 3, cyclic voltammetry was used to detect the hydrogen peroxide sample using the In@CN modified electrode as the working electrode, a platinum wire as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrochemical CV detection parameters were set as follows: starting potential -0.8 V, ending potential +0.2 V, standing time 2 s, scan rate 50 mV / s, and scan segment number 8.

[0017] The hexagonal pyramidal In@CN material modified electrode of the present invention has a large electrochemically active specific surface area, a fast mass transfer rate in the electrochemical process, can improve the reaction activity, and thus can catalyze the progress of the hydrogen peroxide reduction reaction.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention utilizes non-toxic and easily available raw materials, low cost, and low energy consumption to prepare a material with good conductivity and large specific surface area. The prepared material is successfully applied to the electrochemical sensing of hydrogen peroxide.

[0020] 2. The present invention has a lower detection limit of 0.3 mM and a sensitivity of up to 104.2 μA·mM when detecting hydrogen peroxide. −1 .

[0021] 3. The present invention has good anti-interference performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the SEM image of In@CN in the present invention.

[0023] Figure 2 This is the IT diagram of In@CN as a modified electrode for detecting hydrogen peroxide in the present invention.

[0024] Figure 3 This is the IT diagram of the anti-interference when In@CN is used as a modified electrode to detect hydrogen peroxide in the present invention. DETAILED DESCRIPTION

[0025] The preferred embodiments of the present invention will be described in detail below with reference to the examples. It should be understood that the following examples are provided for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art may make various modifications and substitutions to the present invention without departing from the purpose and spirit of the present invention.

[0026] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0027] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0028] The chemicals used in the following examples include indium (III) nitrate hydrate (In(NO₃)₃·xH₂O), N,N-dimethylformamide (DMF), terephthalic acid, KCl, K₃Fe(CN)₆, K₄Fe(CN)₆·3H₂O, Na₂HPO₄·12H₂O, and NaH₂PO₄·2H₂O. The electrolyte used in the performance tests was a 5 mM H₂O₂ solution, and all experiments were conducted at room temperature.

[0029] In the following examples, the morphology of the prepared In@CN was observed using a scanning electron microscope (SEM); the performance test was performed using a Shanghai Chenhua CHI660E electrochemical workstation in a 0.1 M PBS solution containing 5 mM H2O2. Example 1

[0030] A method for preparing an In@CN modified electrode for ultrasensitive detection of hydrogen peroxide comprises the following steps:

[0031] Step 1: 0.2 mmol In(NO3)3·xH2O and 0.4 mmol terephthalic acid were added to 40 mL DMF, stirred and dissolved, and ultrasonically dispersed to obtain a mixed solution;

[0032] Step 2, heating the mixed solution in an oil bath at 120 °C for 30 min;

[0033] Step 3: After the suspension in step 2 is heated and cooled to room temperature, it is rapidly centrifuged at 8000 rpm / min for 5 minutes using a high-speed centrifuge, washed three times with anhydrous ethanol, and dried in a vacuum drying oven at 70°C for 12 hours to obtain In-MIL-68 material;

[0034] Step 4: Weigh a certain amount of In-MIL-68 and pour it into a porcelain boat, then place it in a tube furnace with nitrogen and heat it at 5℃·min -1 The temperature was raised to 500 °C and calcined for 2 h. After cooling naturally to room temperature, the In@CN material was obtained.

[0035] Scanning electron microscopy (SEM) was used to characterize In@CN. Figure 1 As shown, the material morphology is hexagonal pyramid. Example 2

[0036] The prepared In@CN modified electrode material was used for electrochemical detection of hydrogen peroxide. The specific experimental steps are as follows:

[0037] Step 1: Weigh 2.5 mg of In@CN into a centrifuge tube, add 400 μL of ethanol, 75 μL of deionized water, and 25 μL of Nafion solution, mix well, and place the mixture in an ultrasonic cleaner for 10 min to obtain an In@CN suspension.

[0038] Step 2: Use a pipette to draw 5 μL of the suspension and evenly apply it on the bare glassy carbon electrode. After the solvent evaporates and solidifies into a film, add more drops. Repeat this operation ten times to obtain the In@CN modified electrode.

[0039] Step 3: 5, 50, and 500 mmol H2O2 were gradually added to 20 mL of 0.1 mol PBS (pH = 7.0) solution over time to control different H2O2 concentrations;

[0040] In step 4, the In@CN modified electrode was used as the working electrode, the platinum electrode as the counter electrode, and the Ag / AgCl electrode as the reference electrode. The three electrodes were inserted into the mixed solution and connected to the electrochemical workstation. The constant potential time current curve was used to obtain the detection linear range. The detection parameters were set as follows: constant potential: -0.43 V, and different concentrations of hydrogen peroxide were added for detection.

[0041] The results are as follows Figure 2 As shown in the figure, the experiment shows that H2O2 has a certain linear relationship with the response current value within a certain concentration range. The detection limit of the H2O2 reduction reaction on In@CN / GCE is 0.3 mM (S / N=3). According to the linear equation I(μA) =104.2C (mM)-105.1 (R 2 = 0.991) and the sensitivity of the reaction was as high as 104.2 μA·mM −1 . Example 3

[0042] The prepared In@CN modified electrode material is used for anti-interference performance testing when detecting hydrogen peroxide, including the following steps:

[0043] Step 1: Weigh 2.5 mg of In@CN into a centrifuge tube, add 400 μL of ethanol, 75 μL of deionized water, and 25 μL of Nafion solution. Mix thoroughly and place in an ultrasonic bath for 10 minutes to obtain an In@CN suspension.

[0044] Step 2: Use a pipette to draw 5 μL of the suspension and evenly apply it on the bare glassy carbon electrode. After the solvent evaporates and solidifies into a film, add more drops. Repeat this operation ten times to obtain the In@CN modified electrode.

[0045] Step 3: 100 mM of biological small molecules ascorbic acid (AA) and uric acid (UA) and 1000 mM of inorganic salt ions K + 、Na + 、Fe 3+ 、Cl - 、NO3 - 、SO4 2- The other interfering substances were added into 10 mL of 0.1 mol PBS (pH = 7.0) containing 10 mM hydrogen peroxide solution;

[0046] In step 4, the glassy carbon electrode after drop coating with In@CN was used as the working electrode, the platinum electrode was the counter electrode, and the Ag / AgCl electrode was the reference electrode. The three electrodes were inserted into the mixed solution and connected to the electrochemical workstation. The constant potential time current curve was used to obtain the detection linear range. The detection parameters were set as follows: constant potential: -0.43 V, and different interfering substances were added for detection.

[0047] The results are as follows Figure 3 As shown in Figure 3, the electrochemical signals did not change significantly after adding different interferents, which indicates that the In@CN / GCE sensor has good anti-interference ability.

Claims

1. Application of hexagonal pyramidal In@CN material in the detection of hydrogen peroxide, characterized in that: The application uses the following steps: Step 1: Weigh In@CN in a centrifuge tube, add ethanol, deionized water, and Nafion solution, mix well, and then ultrasonicate for 10 minutes to obtain an In@CN suspension. For every 2.5 mg of In@CN, the amounts of ethanol, deionized water, and Nafion solution used are 400 μL, 75 μL, and 25 μL, respectively. Step 2: Pipette 5 μL of In@CN suspension and evenly apply it on the bare glassy carbon electrode. After the solvent evaporates and solidifies into a film, add more drops. Repeat the operation ten times to obtain the In@CN modified electrode. Step 3: Cyclic voltammetry was performed using the In@CN modified electrode as the working electrode, a platinum wire as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrochemical CV detection parameters were set as follows: starting potential -0.8 V, ending potential +0.2 V, holding time 2 s, scan rate 50 mV / s, and scan number 8 to detect the hydrogen peroxide sample. The hexagonal pyramidal In@CN material is prepared by the following steps: Step 1: adding indium (III) nitrate hydrate and terephthalic acid to N,N-dimethylformamide, stirring and dissolving, and ultrasonically dispersing to obtain a mixed solution; the amount ratio of indium (III) nitrate hydrate, terephthalic acid and N,N-dimethylformamide is 0.2 mmol:0.4 mmol:40 mL; Step 2: heating the mixed solution in an oil bath at a temperature of 100-120° C. for 30-60 min; Step 3, cooling the solution heated in step 2 and centrifuging it using a high-speed centrifuge; Step 4: After centrifugation, drying is performed to obtain In-MIL-68 material; Step 5: Pour the In-MIL-68 material into a porcelain boat, then place it in a tubular furnace filled with nitrogen and calcine it. After cooling naturally to room temperature, take it out to obtain the In@CN material.

2. The use according to claim 1, characterized in that The centrifugal separation conditions in step 3 are 9000 rpm / min and 5 min.

3. The use according to claim 1, characterized in that The drying in step 4 is carried out in a vacuum drying oven at 70°C for 12 h.

4. The use according to claim 1, characterized in that In step 5, the calcination conditions were 500 °C for 2 h and 5 °C·min -1 Heating rate to 500 ℃.

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