CuCl nanocrystal for methanol electrochemical sensing and application of CuCl nanocrystal
By preparing high-purity CuCl nanocrystals and modifying the electrodes, the problem of signal instability of electrochemical sensing materials is solved, and accurate detection and stable signal output of methanol concentration are achieved, which is suitable for industrial production and real-time monitoring.
Patent Information
- Application Number
- CN202510542427.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-27
- Publication Date
- 2025-08-01
AI Technical Summary
The activity of existing electrochemical sensing materials rapidly decreases during methanol oxidation reaction, resulting in unstable detection signals and the methanol concentration cannot be accurately determined.
CuCl nanocrystals were used as working electrode materials to prepare high-purity CuCl nanocrystals by simple and efficient liquid phase method, and modified them to glass carbon electrodes, and electrochemical detection of methanol was combined with a three-electrode system.
It realizes the stability of the electrocatalytic methanol oxidation process and reliable signal output, can accurately detect the concentration of methanol solution, and is suitable for large-scale industrial production and real-time monitoring.
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Figure CN120398109A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of preparation and application of nanomaterials, and particularly to a CuCl nanocrystal that can be used for methanol electrochemistry sensing and its application. Background Art
[0002] Methanol, as a basic chemical raw material, is widely used in various industrial production processes, providing great convenience for our lives. However, if methanol is used improperly, it may also become a potential threat. For example, in the production process of alcoholic products, methanol may appear as a harmful substance. If the methanol content in alcoholic products exceeds the safety standard, it may cause serious harm to human health after drinking, including but not limited to vision loss, poisoning reactions, and even life-threatening. Therefore, accurately detecting the concentration of methanol in solution is of crucial significance for ensuring product quality and consumer health. In addition, in the field of environmental protection, by accurately monitoring the methanol content in wastewater, the operation effect of wastewater treatment facilities and the potential risks to the surrounding environment can be effectively evaluated, so as to take corresponding measures to reduce environmental pollution and protect the ecological environment. Therefore, accurately detecting the concentration of methanol in solution is particularly important.
[0003] Currently, the common methods for detecting methanol concentration include density method, refractive index method, gas chromatography, chemical titration method, and infrared spectroscopy. However, each of these methods has its limitations. For example, the density method is easily affected by temperature fluctuations and impurity interference. The refractive index method has strict requirements for sample purity, and any impurity may affect the accuracy of the refractive index. The equipment cost of gas chromatography is relatively high, while the chemical titration method requires professional technicians and has a slow analysis speed. As for the infrared spectroscopy, it is prone to errors when dealing with complex samples.
[0004] Compared with other detection technologies, electrochemistry sensing technology stands out with its advantages of high sensitivity, fast response, excellent selectivity, and convenient miniaturization and integration of equipment, and is particularly suitable for real-time monitoring and on-site rapid detection. Generally, an electrochemistry sensor includes a working electrode, a counter electrode, and a reference electrode. The working electrode is the place where an electrochemical reaction occurs. When the target substance undergoes an oxidation or reduction reaction on the surface of the working electrode, a current or potential change related to the concentration of the target substance will be generated. Under certain conditions, the current generated by the electrochemical reaction is proportional to the concentration of the target substance. By measuring the magnitude of the current, the concentration of the target substance can be determined. However, currently, the research on detecting the concentration of methanol solution by electrochemical methods is relatively less. This is mainly because most working electrode materials (Pt-based nanocrystals) have a rapid decline in activity during the electrocatalytic methanol oxidation reaction, resulting in unstable detection signals.
[0005] Therefore, finding a cost-effective working electrode material that can stably electrocatalyze methanol oxidation is the key to solving the above problems.
[0006] Due to their unique physical and chemical properties, CuCl nanocrystals have been widely used in the catalytic process of chemical product synthesis and the material preparation of optical modulators and gas sensors. However, there are few reports on their research as electrochemical sensing materials. This is mainly because the current preparation process of CuCl nanocrystals is not yet mature. Especially in the liquid-phase preparation process, impurities are often introduced, which has an adverse effect on the analysis of the application performance of the materials. Therefore, developing a method capable of preparing high-purity CuCl nanocrystals is crucial for expanding their applications in the field of electrochemical sensing. Summary of the Invention
[0007] The problem to be solved by the present invention is that the existing electrochemical sensing materials in the background technology have unstable signals and cannot accurately determine the methanol concentration. It is first proposed to use CuCl for the electrocatalytic methanol oxidation reaction. Compared with traditional working electrode materials, the working electrode modified with CuCl nanocrystals exhibits better stability in electrocatalytic methanol oxidation, and its signal is not prone to rapid attenuation. Through chronoamperometry, the electrical signal can be accurately detected to judge the concentration of the liquid to be measured.
[0008] The preparation method of CuCl nanocrystals is as follows:
[0009] (1) Using CuCl2 as the solute and deionized water as the solvent, prepare a CuCl2 solution with a concentration of 10.2 - 10.5 mg / mL, stir and mix evenly to obtain Solution 1;
[0010] (2) According to the ratio, add KCl powder to Solution 1 (the mass of KCl added per milliliter of the mixed solution 2 is 2.6 - 3.0 mg), stir evenly to obtain Mixed Solution 1;
[0011] (3) Add an ascorbic acid solution with a concentration between 0.9 - 1.0 mol / L to Mixed Solution 1 (the volume ratio of ascorbic acid added to Mixed Solution 1 is 1:3) to obtain Mixed Solution 2;
[0012] (4) Heat Mixed Solution 2 in an environment of 60 °C, stir and react for 6 hours to obtain an off-white precipitate;
[0013] (5) Use a separatory funnel to separate the off-white precipitate obtained from the reaction from the reactants;
[0014] (6) Wash the filtered off-white precipitate with deionized water and ethanol once each, and use a blast dryer to dry the precipitate;
[0015] (7) The obtained dried powder is high-purity CuCl nanocrystals.
[0016] The steps of applying CuCl nanocrystals to the electrochemically sensing methanol oxidation are as follows:
[0017] (1) A glassy carbon electrode modified with the prepared high-purity CuCl nanocrystals;
[0018] (2) Using a 1 mol / L KOH solution as the electrolyte, different concentrations of methanol solutions are configured in the electrolytic cell;
[0019] (3) Adopting a three-electrode system, the glassy carbon electrode modified with the prepared high-purity CuCl nanocrystals is used as the working electrode, the Ag / AgCl electrode is used as the reference electrode, and the Pt wire electrode is used as the counter electrode. These electrodes are placed in the electrolytic cell containing the methanol solution, connected to the electrochemical workstation, the working potential is set, and the chronoamperometric density of different concentrations of methanol is measured;
[0020] (4) Based on the response current density and the concentration of the known methanol solution, a calibration function is established;
[0021] (5) The solution to be measured is pretreated by adding KOH powder to make the concentration of KOH in the solution 1 mol / L. The working potential is set, the chronoamperometric density is measured, and according to the calibration curve of the response current density and methanol concentration obtained from the test, the concentration value of methanol in the solution to be measured is calculated.
[0022] Implementing the present invention has the following beneficial effects:
[0023] 1. A method for preparing impurity-free CuCl nanocrystals is provided.
[0024] The present invention proposes a green and efficient preparation process for CuCl nanocrystals. This method does not use strong reducing agents and toxic reagents and can be completed under mild reaction conditions, combining environmental friendliness and operational convenience. The entire preparation process is simple and efficient, and the produced CuCl nanocrystals have excellent purity, providing an important guarantee for the application expansion of CuCl in the field of electrochemical sensing.
[0025] 2. Innovation of methanol detection electrode materials: Empowering large-scale applications of electrochemical sensing with low-cost CuCl
[0026] The present invention discloses a high-cost-effective catalytic electrode material for methanol oxidation, innovatively using CuCl as the core material for electrochemically detecting methanol. Compared with traditional electrodes, this material has the significant advantages of low cost and high stability, not only adapting to large-scale industrial production and recycling scenarios, but also effectively promoting the industrialization process of methanol concentration electrochemical detection technology.
[0027] 3. Transcending the limitations of commercial Pt / C, using CuCl as the working electrode material to achieve stable output of methanol detection electrical signals
[0028] Compared with the rapid decay of the electrical signal of traditional Pt / C electrode materials, the electrochemical sensing using CuCl as the working electrode can obtain a stable electrical signal, effectively ensuring the accuracy of the detection results. In addition, the CuCl electrode also exhibits excellent catalytic activity for methanol oxidation, which makes the CuCl-based electrochemical sensor have significant advantages in real-time monitoring and rapid response, providing strong technical support for the dynamic monitoring of methanol concentration. Description of the Drawings
[0029] Figure 1 It is the X-ray diffraction pattern of the high-purity CuCl obtained in Example 1 of the present invention.
[0030] Figure 2 It is the linear voltammetric scanning curve of the high-purity CuCl nanocrystals obtained in Example 1 in methanol aqueous solutions with different concentrations of methanol.
[0031] Figure 3 It is the chronoamperometric curve of the high-purity CuCl nanocrystals obtained in Example 1 in different methanol concentrations.
[0032] Figure 4 It is the fitting function of the response current density and methanol concentration in Application Example 1 of the present invention.
[0033] Figure 5 It is the chronoamperometric curve of the high-purity CuCl obtained in Example 1 at a constant potential in methanol solutions with concentrations of 25 mmol / L and 50 mmol / L.
[0034] Figure 6 It is the chronoamperometric curve of the commercially purchased Pt / C at a constant potential in a 25 mmol / L methanol solution. Detailed Embodiments
[0035] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.
[0036] Example 1: Preparation of High-Purity CuCl Nanocrystals
[0037] (1) Using CuCl2 as the solute and deionized water as the solvent, a CuCl2 solution with a volume of 37.5 mL and a concentration of 10.2 mg / mL was prepared, stirred and mixed evenly to obtain Solution 1;
[0038] (2) 0.1 g of KCl was added to Solution 1 and stirred evenly to obtain Mixed Solution 1;
[0039] (3) A 12.5 mL ascorbic acid solution with a concentration of 1 mol / L was prepared and added to Mixed Solution 1, stirred and mixed evenly to obtain Mixed Solution 2;
[0040] (4) Place the mixed solution 2 in an environment provided by a 60 °C water bath and heat it, stirring and reacting for 6 hours to obtain a grayish-white precipitate.
[0041] (5) Use a separating funnel to separate the grayish-white precipitate obtained from the reaction from the reactants;
[0042] (6) Wash the filtered grayish-white reactant with deionized water and ethanol once each, and dry it with a 60 °C blower for 2 hours.
[0043] (7) The dried grayish-white powder is CuCl nanocrystals.
[0044] In the above preparation process, CuCl2 is used as a precursor in step (1) to provide soluble divalent Cu ions. In step (4), ascorbic acid is used as a reducing agent to reduce CuCl2 to CuCl nanocrystals. In step (2), KCl is used as an additive, and its function is to inhibit the formation of by-products such as Cu2O. In order to observe the morphological characteristics of the samples, we carried out field emission scanning electron microscopy (FESEM) tests on the samples prepared in Example 1. The test results show that the products exhibit a nanoparticle morphology and have good monodispersity.
[0045] In order to analyze the composition of the samples, we carried out X-ray diffraction tests on the products (performed in an air environment), and the X-ray diffraction pattern is as attached Figure 1 shown. As Figure 1 shown, the characteristic peaks of the obtained products are completely consistent with the diffraction peaks of the No. 82-2114 standard JCPDS card. Therefore, it can be confirmed that the obtained products are pure CuCl.
[0046] Since no diffraction peaks of oxides (such as Cu2O and CuO) or other impurities are observed in the attachment Figure 1 , this proves that the CuCl nanocrystals prepared by the present invention have good antioxidant properties and do not need to be stored under a protective gas. This is because the ascorbic acid added in step (3) is in excess. In addition to acting as a reducing agent, ascorbic acid molecules can also adsorb on the surface of CuCl, isolating contact with oxygen molecules in the air, thus acting as an antioxidant.
[0047] The present invention uses a simple liquid phase method to successfully prepare high-purity CuCl nanocrystals. These nanocrystals exhibit excellent stability and can be stably stored in air, facilitating wide application in large-scale production. The entire preparation process only requires simple equipment and a mild reaction temperature without extreme high temperatures, thus minimizing the safety problems and energy consumption caused during the material preparation process.
[0048] Application Example 1: Detecting the methanol concentration in a solution using an electrode modified with high-purity CuCl nanocrystals
[0049] (1) Using absolute ethanol, prepare a suspension of the prepared high-purity CuCl with a concentration of 3 mg / mL. Take 4 μL of the above suspension and drop it on the surface of a glassy carbon electrode with a diameter of 3 mm. After the ethanol has evaporated, then drop 3 μL of a perfluorosulfonic acid-based polymer solution with a concentration of 0.1% as a protective film. After the solution has evaporated, the obtained electrode is a working electrode modified with nanocrystals.
[0050] (2) Use a 1 mol / L KOH solution as the electrolyte, prepare a series of methanol solutions with different concentrations (ranging from 0 to 375 mmol / L), and then place these solutions in an electrolytic cell.
[0051] (3) By the three-electrode method, use the glassy carbon electrode modified with the prepared high-purity CuCl as the working electrode, Ag / AgCl as the reference electrode, and a commercial Pt wire as the counter electrode; place these electrodes in the electrolytic cell and connect them to an electrochemical workstation. Set the working potential to 0.9 V vs Ag / AgCl, measure the chronoamperometric density of methanol with different concentrations, and the test duration for each concentration gradient is 100 seconds.
[0052] (4) Based on the response current density and the concentration of the standard methanol solution with a known concentration, establish a calibration curve.
[0053] (5) Pretreat the solution to be measured, add KOH powder to make the concentration of KOH in the solution 1 mol / L, set the working potential to 0.9 V vs Ag / AgCl, test the chronoamperometric density, and calculate the concentration value of methanol in the solution to be measured according to the obtained response current density and the calibration curve.
[0054] First, to prove that CuCl can achieve the electrocatalytic methanol oxidation process, we respectively tested the linear voltammetry scan curves of electrolytes containing methanol solutions with concentrations of 0 mmol / L, 25 mmol / L, and 50 mmol / L. As shown in the attached Figure 2 instructions, when the methanol concentration in the electrolyte increased from 0 mmol / L to 25 mmol / L, an obvious oxidation peak appeared at 0.9 V vs Ag / AgCl, which corresponded to the oxidation reaction process of the methanol solution, proving that in a 1 mol / L KOH solution, the oxidation potential of methanol is 0.9 V vs Ag / AgCl. When the methanol concentration in the electrolyte increased to 50 mmol / L, the peak current density of this oxidation peak further increased, which was caused by the increase in the amount of methanol participating in the oxidation without an increase in mass, resulting in an increase in the amount of charge participating per unit time.
[0055] Therefore, we can conclude that CuCl can achieve electrocatalytic oxidation of methanol. During the electrocatalytic oxidation reaction, there is a correlation between the concentration of methanol and the peak current density, indicating that CuCl can be used as an effective electrochemical sensing material.
[0056] Therefore, we tested the chronoamperometric curves of the working electrode modified with CuCl nanocrystals in methanol solutions with different concentrations (corresponding to step 3 of Application Example 1). The results are shown in the attached Figure 3 specification. As shown, as the concentration of methanol increases, the gradient of the response current density also increases, and the signal remains stable, which is convenient for obtaining parameters from the calibration curve. The fitting function of the response current density and the methanol concentration is as Figure 4 shown. The concentration range from 0 to 375 mmol / L is relatively large, and the fitting function is a linear piecewise function.
[0057] When the methanol concentration ranges from 0 to 75 mmol / L, the fitting function of the chronoamperometric response current density and the methanol concentration is: J1 (μA / cm 2 ) = 16.912C1 (mmol / L) + 278.8.
[0058] When the methanol concentration ranges from 75 to 175 mmol / L, the fitting function of the chronoamperometric response current density and the methanol concentration is: J2 (μA / cm 2 ) = 6.952C2 (mmol / L) + 1025.2.
[0059] When the methanol concentration ranges from 175 to 325 mmol / L, the fitting function of the chronoamperometric response current density and the methanol concentration is: J3 (μA / cm 2 ) = 1.557C3 (mmol / L) + 1978.1.
[0060] The above calibration curves can be used to calculate the concentration value of methanol in the test solution in step (5). In addition, from the three-segment calibration curves, it can be seen that the CuCl nanocrystals of the present invention have high sensitivity in low-concentration methanol solutions. The sensitivity in the range of 0 to 75 mmol / L is 16912 μA / cm 2 ·(mol / L), which is suitable for accurate detection of low-concentration samples.
[0061] Compared with the traditional Pt / C electrode material, the electrochemical sensing using CuCl as the working electrode in the present invention can achieve stable electrical signal output, effectively ensuring the accuracy of the detection results. To verify this view, we further analyzed the chronoamperometric curves of high-purity CuCl at a constant potential in 25 mmol / L and 50 mmol / L methanol solutions.
[0062] As shown in the attached specification Figure 5As shown, within a response time of 100 seconds, the response current density of CuCl to 25 mmol / L methanol increased from 655.45 μA / cm 2 to 734.10 μA / cm 2 , with a change amplitude of +11.9%. The response current density to a 50 mmol / L methanol solution decreased from 1209.11 μA / cm 2 to 1166.22 μA / cm 2 , with a change amplitude of -3.5%.
[0063] For a more in-depth comparison, we further tested the purchased commercial Pt / C. Chronoamperometry curves were measured at a constant potential in a 25 mmol / L methanol solution. The specific steps refer to Comparative Example 1.
[0064] Comparative Example 1: Detection of methanol concentration in solution using an electrode modified with commercial Pt / C
[0065] (1) Using absolute ethanol, prepare a suspension of commercial Pt / C with a concentration of 3 mg / mL. Take 4 μL of the above suspension and drop it on the surface of a glassy carbon electrode with a diameter of 3 mm. After the ethanol has evaporated, then drop 3 μL of a 0.1% perfluorosulfonic acid polymer solution as a protective film. After the solution has evaporated, the resulting electrode is a working electrode modified with nanocrystals.
[0066] (2) Use 1 mol / L KOH solution as the electrolyte and prepare a methanol solution with a concentration of 25 mmol / L. Then place this solution in an electrolytic cell;
[0067] (3) By the three-electrode method, use the commercial Pt / C modified electrode as the working electrode, Ag / AgCl as the reference electrode, and a commercial Pt wire as the counter electrode; place these electrodes in the electrolytic cell and connect them to an electrochemical workstation. Set the potential to 0.9 V vs Ag / AgCl and measure the chronoamperometry density of a 25 mmol / L methanol solution for a duration of 200 seconds.
[0068] As shown in the attached instructions Figure 6 , it can be clearly seen that under constant potential conditions, the response signal of the Pt / C modified working electrode to a 25 mmol / L methanol solution is significantly lower than that of the CuCl modified working electrode.
[0069] In addition, the electrical signal decays rapidly. Within only 200 seconds, the signal intensity decreases from 453.35 μA / cm 2 to 73.66 μA / cm 2 , indicating that real-time and accurate detection of the methanol solution concentration cannot be achieved.
[0070] In summary, this article introduces a high-purity CuCl nanocrystal and its preparation method. The product obtained by this method can be used as an electrochemical sensing material, and its output signal has good stability, enabling accurate detection of the concentration of methanol solution. It should be noted that the above is the preferred embodiment of the invention. For those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.
Claims
1. A CuCl nanocrystal for methanol electrochemical sensing and its application, characterized in that, The preparation method of CuCl nanocrystals is as follows: (1) Using CuCl2 as the solute and deionized water as the solvent, prepare a CuCl2 solution with a concentration of 10.2 - 10.5 mg / mL, stir and mix evenly to obtain Solution 1; (2) According to the ratio, add KCl powder to Solution 1, stir and mix evenly to obtain Mixed Solution 1; (3) According to the volume ratio, add an ascorbic acid solution with a concentration between 0.9 - 1.0 mol / L to Mixed Solution 1 to obtain Mixed Solution 2; (4) Heat Mixed Solution 2 in an environment of 60 °C, stir and react for 6 hours to obtain a grayish-white precipitate; (5) Use a separating funnel to separate the grayish-white precipitate obtained from the reaction from the reactants; (6) Wash the filtered grayish-white precipitate with deionized water and ethanol once each, and use a blast dryer to dry the precipitate; (7) The dried powder obtained is high-purity CuCl nanocrystals; As described in step (2), the mass of KCl added to each milliliter of Solution 1 is 2.6 - 3.0 mg; As described in step (3), the volume ratio of ascorbic acid to Mixed Solution 1 in the reaction is 1:
3.
2. A CuCl nanocrystal, characterized in that, Obtained by the preparation method described in claim 1.
3. A CuCl nanocrystal for methanol electrochemical sensing and its application, characterized in that the detection of the concentration of methanol liquid can be realized by using the CuCl nanocrystal, and the specific steps are as follows: (1) A glassy carbon electrode modified with the prepared CuCl nanocrystal; (2) Using a 1 mol / L KOH solution as the electrolyte, prepare methanol solutions with different concentrations in an electrolytic cell; (3) Adopt a three-electrode system, use the glassy carbon electrode modified with the prepared high-purity CuCl nanocrystal as the working electrode, the Ag / AgCl electrode as the reference electrode, and the Pt wire electrode as the counter electrode. Place these electrodes in the above-mentioned electrolytic cell, connect them to an electrochemical workstation, set the working potential, and measure the chronoamperometric density of methanol with different concentrations; (4) Based on the response current density and the concentration of the known methanol solution, establish a fitting function; (5) Pretreat the solution to be measured, add KOH powder to make the concentration of KOH in the solution 1 mol / L, set the working potential, test the chronoamperometric density, and calculate the concentration value of methanol in the solution to be measured according to the response current density obtained from the test and the methanol concentration fitting function.