A self-supporting electrochemical sensing material, a preparation method therefor and applications thereof

Abstract

The application belongs to the technical field of glucose detection, and particularly relates to a self-supporting electrochemical sensing material and a preparation method and application thereof. The self-supporting electrochemical sensing material comprises a foam nickel / cobalt oxide composite material obtained by growing cobalt oxide on the surface of foam nickel, and has a 3D vertical directional arrangement structure. The preparation method comprises the following steps: (1) transferring a mixed solution of cobalt salt, urea and ammonium fluoride into a high-pressure kettle, and placing the high-pressure kettle into foam nickel for high-temperature reaction; (2) rinsing the foam nickel after high-temperature reaction with water, and drying and high-temperature calcining the foam nickel to obtain the self-supporting electrochemical sensing material with the 3D vertical directional arrangement structure. Through a simple and economical hydrothermal synthesis reaction, a novel layered networked cobalt oxide nanosheet array structure is directly grown on the foam nickel, and the obtained foam nickel and cobalt oxide with the 3D vertical directional arrangement nanostructure have good glucose catalytic performance, and can significantly realize efficient detection of glucose in a non-invasive manner.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of glucose detection, and particularly relates to a self-supporting electrochemical sensing material and a preparation method and application thereof. BACKGROUND

[0002] Glucose is an important compound in the body of living beings, and has an important influence on the health of human bodies. Abnormal glucose concentration in the human body will cause various diseases, for example, diabetes, high blood pressure, and hypoglycemic neurosis. Therefore, the detection of the glucose content of the human body, including the blood glucose and urine glucose content, is very important.

[0003] Venous blood detection needs to extract venous blood for blood glucose detection, so the use scenario of this method is limited to hospitals or outpatient departments, and the detection time is relatively long, which is not suitable for daily life and the case of frequent detection of blood glucose concentration, and users are also difficult to detect by themselves. Non-invasive detection has greater advantages than invasive detection and minimally invasive detection, and does not bring the risk of infection to patients when extracting samples, and is fast and convenient to measure. The current research direction of non-invasive blood glucose detection includes gas chromatography, spectrophotometry, optical rotation method, and electrochemical detection method, and the most widely used and mature technology is electrochemical electrode detection technology.

[0004] According to whether an enzyme catalyst is contained, the electrochemical glucose sensor can be divided into an electrochemical enzyme glucose sensor and an electrochemical non-enzyme glucose sensor. The enzyme-based electrochemical glucose sensor mainly utilizes the specificity and high efficiency of the enzyme to the substrate, but the enzyme sensor has many problems in the actual production process. First, the stability is poor, and the glucose oxidase quickly loses activity under the condition of PH<2 or PH>8 or high temperature, so the stability of the enzyme-based electrochemical glucose sensor is poor. Second, the reproducibility is poor, and the process of making the enzyme is complex, which leads to an increase in cost and poor reproducibility. SUMMARY

[0005] The self-supporting electrochemical sensing material can realize efficient detection of glucose in a non-invasive manner.

[0006] The self-supporting electrochemical sensing material comprises a foam nickel / cobalt oxide composite material obtained by growing cobalt oxide on the surface of foam nickel.

[0007] Nanometer structure can significantly improve the specific surface area, shorten the charge transport path, promote mass diffusion and introduce unique size and shape related characteristics, which has great potential to improve the catalytic performance of catalyst. Organizing these nanometer structures into certain structures, such as multilayer, interconnection network and array, can further improve the catalytic effect. The 3D vertically arranged foam nickel nanometer structure has high surface area and excellent electrical conductivity, which can improve the catalytic effect on glucose, and the nickel element is abundant, which can be used as a catalytic material for glucose.

[0008] Further, the structure of the above foam nickel / cobalt oxide composite material is a 3D vertically arranged structure.

[0009] Further, the mass ratio of foam nickel and cobalt oxide in the above foam nickel / cobalt oxide composite material is 1-6:1. If the content of cobalt oxide is too low, the response current intensity of the composite material to glucose will be small, the reliability and stability of the detection will be reduced, and if the content of cobalt oxide is too high, the 3D vertically arranged structure of the composite material will be destroyed, resulting in a small response current intensity of the composite material to glucose, reduced reliability of the detection, and reduced ability to detect glucose.

[0010] Another object of the present application is to provide a preparation method of the above self-supporting electrochemical sensing material, comprising the following steps:

[0011] (1) transferring a mixed solution of cobalt salt, urea and ammonium fluoride into an autoclave, and placing it into foam nickel for high temperature reaction;

[0012] (2) rinsing the foam nickel after high temperature reaction with water, drying and then high temperature calcining to obtain a self-supporting electrochemical sensing material with a 3D vertically arranged structure.

[0013] Further, the foam nickel is pretreated by acetone ultrasonic, hydrochloric acid soaking, cleaning and drying in sequence before being placed into the autoclave. Acetone ultrasonic can remove grease and dirt on the surface of the foam nickel, and hydrochloric acid soaking can react to remove the oxide film on the surface of the foam nickel, which is beneficial to the subsequent generation of cobalt oxide on the surface of the foam nickel.

[0014] Further, the cobalt salt is one or both of cobalt chloride hexahydrate and cobalt nitrate hexahydrate.

[0015] Further, the concentration of hydrochloric acid is 0.1-0.5 mol / L, and the soaking time is 10-30 min.

[0016] Further, the concentration of the cobalt salt in step (1) is 0.001-0.005 g / ml, the concentration of the urea solution is 0.01-0.05 g / ml, and the concentration of the ammonium fluoride solution is 0.01-0.05 g / ml.

[0017] Further, the temperature of the high-temperature reaction in step (1) is 120-160 DEG C, and the time is 1-5 h.

[0018] Further, the temperature of the high-temperature calcination in step (2) is 200-500 DEG C, and the time is 1-3 h.

[0019] Further, the drying temperature in step (2) is 60-100 DEG C, and the time is 10-20 h.

[0020] The self-supporting electrochemical sensing material described above can be used for detecting the glucose content, such as the glucose content in human body fluid.

[0021] Compared with the prior art, the technical scheme of the present application has the following beneficial effects:

[0022] (1) The self-supporting electrochemical sensing material of the present application is a foam nickel and cobalt oxide with 3D vertically aligned nanostructure, has good glucose catalytic performance, and can significantly realize efficient detection of glucose;

[0023] (2) The foam nickel with 3D vertically aligned special structure has good catalytic activity, large specific surface area, high stability and excellent conductivity, and can improve the catalytic effect on glucose;

[0024] (3) The cobalt oxide nanosheet array nanostructure can quickly obtain a stable response current, greatly improving the stability, repeatability and reliability of the sensor structure;

[0025] (4) A novel layered networked cobalt oxide nanosheet array structure is directly grown on the foam nickel through a simple and economical hydrothermal synthesis reaction, and the preparation method is simple, efficient and low in cost. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 SEM image of the self-supporting electrochemical sensing material obtained in Example 1;

[0027] Figure 2 Cyclic voltammogram of the self-supporting electrochemical sensing material obtained in Example 1 under different glucose concentrations;

[0028] Figure 3 Current-time curve investigation of the self-supporting electrochemical sensing material obtained in Example 1 as a working electrode in a three-electrode system;

[0029] Figure 4 Linear fitting plot of current intensity vs. glucose concentration for the self-supported electrochemical sensing material obtained in Example 1 as working electrode;

[0030] Figure 5 Current-time plot for glucose selectivity of the self-supported electrochemical sensing material obtained in Example 1 as working electrode;

[0031] Figure 6 Anti-chloride ion poisoning performance test of the self-supported electrochemical sensing material obtained in Example 1 as working electrode;

[0032] Figure 7 Reproducibility investigation plot of current-time plot for the self-supported electrochemical sensing material obtained in Example 1 as working electrode. DETAILED DESCRIPTION

[0033] The technical solutions of the present application are further described and explained below by specific examples and drawings. It should be understood that the specific examples described herein are only used to help understand the present application and are not used to limit the present application. The drawings used herein are only used to better illustrate the disclosed content of the present application and do not limit the scope of protection. If not specifically stated, the raw materials used in the examples of the present application are all commonly used raw materials in the art, and the methods used in the examples are all conventional methods in the art.

[0034] Example 1

[0035] The preparation method of the self-supported electrochemical sensing material in this example includes the following steps:

[0036] (1) 0.2 g of foamed nickel was first treated with ultrasound in acetone for 15 min, washed clean with deionized water, immersed in 0.1 mol / L hydrochloric acid for 25 min, washed with deionized water and then dried with nitrogen;

[0037] (2) 0.3 g of cobalt nitrate hexahydrate, 1.0 g of urea and 0.74 g of ammonium fluoride were dissolved in 40 ml of deionized water to form a mixed solution, the mixed solution was transferred to an autoclave, and the foamed nickel obtained in step (1) was placed in the autoclave, reacted at 150°C for 3 h, and cooled to room temperature with water;

[0038] (3) The foamed nickel after high-temperature reaction was washed clean with water, dried at 80°C for 10 h, and then placed in a tube furnace and heated to 400°C for 2 h to obtain a self-supported electrochemical sensing material with 3D vertically aligned structure.

[0039] Example 2

[0040] The preparation method of the self-supported electrochemical sensing material in this example includes the following steps:

[0041] (1) 0.2 g of the nickel foam was first treated with ultrasound in acetone for 15 min, washed clean with deionized water, soaked in 0.3 mol / L hydrochloric acid for 15 min, washed with deionized water and dried with nitrogen;

[0042] (2) 0.33 g of cobalt chloride hexahydrate, 1.0 g of urea and 0.74 g of ammonium fluoride were dissolved in 40 ml of deionized water to form a mixed solution, the mixed solution was transferred to an autoclave, and the nickel foam obtained in step (1) was placed in the autoclave and reacted at 140°C for 3 h, and then cooled to room temperature with water;

[0043] (3) The nickel foam after high-temperature reaction was washed clean with water, dried at 70°C for 15 h, placed in a tube furnace and heated to 350°C for 2 h to obtain a self-supporting electrochemical sensing material with a 3D vertically aligned structure.

[0044] Example 3

[0045] The preparation method of the self-supporting electrochemical sensing material of the present example comprises the following steps:

[0046] (1) 0.5 g of the nickel foam was first treated with ultrasound in acetone for 15 min, washed clean with deionized water, soaked in 0.2 mol / L hydrochloric acid for 25 min, washed with deionized water and dried with nitrogen;

[0047] (2) 0.4 g of cobalt nitrate hexahydrate, 1.0 g of urea and 0.74 g of ammonium fluoride were dissolved in 50 ml of deionized water to form a mixed solution, the mixed solution was transferred to an autoclave, and the nickel foam obtained in step (1) was placed in the autoclave and reacted at 150°C for 3 h, and then cooled to room temperature with water;

[0048] (3) The nickel foam after high-temperature reaction was washed clean with water, dried at 75°C for 15 h, placed in a tube furnace and heated to 300°C for 3 h to obtain a self-supporting electrochemical sensing material with a 3D vertically aligned structure.

[0049] Example 4

[0050] The preparation method of the self-supporting electrochemical sensing material of the present example comprises the following steps:

[0051] (1) 0.4 g of cobalt nitrate hexahydrate, 1.0 g of urea and 0.74 g of ammonium fluoride were dissolved in 40 ml of deionized water to form a mixed solution, the mixed solution was transferred to an autoclave, and 0.2 g of the nickel foam was placed in the autoclave and reacted at 150°C for 3 h, and then cooled to room temperature with water;

[0052] (2) The nickel foam after high-temperature reaction was washed clean with water, dried at 80°C for 10 h, placed in a tube furnace and heated to 400°C for 2 h to obtain a self-supporting electrochemical sensing material with a 3D vertically aligned structure.

[0053] Comparative Example 1

[0054] The preparation method of the self-supporting electrochemical sensing material of the present comparative example comprises the following steps:

[0055] (1) 0.2 g of the nickel foam was first treated with ultrasound in acetone for 15 min, cleaned with deionized water, soaked in 0.1 mol / L hydrochloric acid for 25 min, and then cleaned with deionized water and dried with nitrogen;

[0056] (2) 0.08 g of cobalt nitrate hexahydrate, 1.0 g of urea and 0.74 g of ammonium fluoride were dissolved in 40 ml of deionized water to form a mixed solution, the mixed solution was transferred to an autoclave, and the nickel foam obtained in step (1) was placed in the autoclave, reacted at 150℃ for 3 h, and cooled to room temperature with water;

[0057] (3) The nickel foam after high-temperature reaction was washed with water, dried at 80℃ for 10 h, and then placed in a tube furnace and heated to 400℃ for 2 h to obtain a self-supporting electrochemical sensing material with a 3D vertically aligned structure.

[0058] Comparative Example 2

[0059] The preparation method of the self-supporting electrochemical sensing material of the present comparative example comprises the following steps:

[0060] (1) 0.2 g of the nickel foam was first treated with ultrasound in acetone for 15 min, cleaned with deionized water, soaked in 0.1 mol / L hydrochloric acid for 25 min, and then cleaned with deionized water and dried with nitrogen;

[0061] (2) 1.18 g of cobalt nitrate hexahydrate, 1.0 g of urea and 0.74 g of ammonium fluoride were dissolved in 40 ml of deionized water to form a mixed solution, the mixed solution was transferred to an autoclave, and the nickel foam obtained in step (1) was placed in the autoclave, reacted at 150℃ for 3 h, and cooled to room temperature with water;

[0062] (3) The nickel foam after high-temperature reaction was washed with water, dried at 80℃ for 10 h, and then placed in a tube furnace and heated to 400℃ for 2 h to obtain a self-supporting electrochemical sensing material with a 3D vertically aligned structure.

[0063] The self-supporting electrochemical sensing material prepared by the present application has a 3D vertically aligned nanostructure, as shown in Figure 1 . With the increase of the glucose content in the electrolyte, the oxidation peak response current of Co 2+ →Co 3+ in the cyclic voltammetry curve will also increase, as shown in Figure 2 , indicating that the self-supporting 3D vertically aligned nickel foam electrode has excellent ability to electrocatalytically oxidize glucose.

[0064] The self-supporting electrochemical sensing material obtained in Example 1 was used as the working electrode, a platinum plate was used as the auxiliary electrode, and Ag / AgCl was used as the reference electrode in a three-electrode system in an electrochemical workstation. The working electrode was electrochemically tested in a 0.1 mol / L NaOH electrolyte. At a voltage working interval of 0.5 V-0.6 V, 5 μmol / L glucose was added once, 10 μmol / L glucose was added twice, 50 μmol / L glucose was added four times, 100 μmol / L glucose was added four times, 200 μmol / L glucose was added three times, 400 μmol / L glucose was added twice, and 500 μmol / L glucose was added four times to the electrolyte under uniform stirring, and the current-time curve obtained by testing is shown in FIG. 6. Figures 3-4 When a certain concentration of glucose was added to the system, the self-supporting Ni@CoO nanosheet electrode generated a corresponding response current intensity, and there was a certain linear relationship between the two. After processing and fitting the glucose concentration and the response current intensity generated thereby, the fitting equation was y = 27.67941x + 0.64845 (R 2 = 0.994), and it was found that the self-supporting Ni@CoO nanosheet electrode had good linearity and sensitivity in electrocatalytic oxidation of glucose.

[0065] Whether certain components present in human blood glucose, such as sodium ions, chloride ions, dopamine, ascorbic acid, amino acids, etc., would interfere with the determination results of glucose was detected, as shown in FIG. 8. Figure 5 The results showed that the response current intensity generated by other interferents was much smaller than that generated by glucose, indicating that the obtained self-supporting electrochemical sensing material had excellent anti-interference ability.

[0066] A 100:1 ratio was used to evaluate whether chloride ions would have a toxic effect on the electrocatalytic activity of the obtained self-supporting electrochemical sensing material as the working electrode, as shown in FIG. 9. Figure 6 The results showed that chloride ions had no toxic effect on the electrocatalytic activity of the self-supporting electrochemical sensing material as the working electrode and would not affect the detection of glucose.

[0067] Reproducibility is an important parameter for verifying the uniformity of sample quality and evaluating the accuracy of sample detection results. Under the optimal potential, the same self-supporting electrochemical sensing material was used as the working electrode to determine 0.2 mmol / L glucose five times in parallel, and the response current intensity of the electrode to the same amount of glucose under the same conditions five times was obtained, as shown in FIG. 10. Figure 7 The results showed that the self-supporting electrochemical sensing material as the working electrode had good reproducibility when detecting glucose.

[0068] The self-supporting Ni@CoO nanosheet electrode obtained in the above examples and comparative examples was subjected to non-enzymatic electrocatalytic oxidation of glucose performance test, using the three-electrode system as described above, using current-time curve test technology, under the working voltage of 0.55 V, 0.2 mmol·L –1 of glucose was added to the electrolyte under uniform stirring, and current-time data was obtained. The response current intensity of the self-supporting electrochemical sensing material obtained in Example 1 to glucose was only 22.5 mA / cm 2 , the response current intensity of the self-supporting electrochemical sensing material obtained in Example 2 to glucose was only 22.0 mA / cm 2 , the response current intensity of the self-supporting electrochemical sensing material obtained in Example 3 to glucose was only 21.3 mA / cm 2 , the response current intensity of the self-supporting electrochemical sensing material obtained in Example 4 to glucose was only 20.5 mA / cm 2 , the response current intensity of the self-supporting electrochemical sensing material obtained in Comparative Example 1 to glucose was only 13.0 mA / cm 2 , the response current intensity of the self-supporting electrochemical sensing material obtained in Comparative Example 2 to glucose was only 16.2 mA / cm 2 . It can be seen that too low or too high cobalt oxide content will result in smaller response current intensity of the composite material to glucose, lower reliability and stability of detection, and lower ability to detect glucose.

[0069] Finally, it should be noted that the specific examples described herein are merely illustrative of the spirit of the present application, and are not limited to the embodiments of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described examples or replace them with similar ways. Here, all embodiments do not need to be fully described. Any obvious changes or variations derived from the spirit of the present application still fall within the scope of the present application, and any additional limitations are contrary to the spirit of the present application.

Claims

1. A method of preparing a self-supporting electrochemical sensing material, characterized by, Comprising the following steps: (1) 0.2 g of foamed nickel was first treated with ultrasound in acetone for 15 min, washed clean with deionized water, soaked in 0.1 mol / L hydrochloric acid for 25 min, washed with deionized water and dried with nitrogen; (2) 0.3 g of cobalt nitrate hexahydrate, 1.0 g of urea and 0.74 g of ammonium fluoride were dissolved in 40 ml of deionized water to form a mixed solution, the mixed solution was transferred to a high-pressure kettle, and the foamed nickel obtained in step (1) was put into the high-pressure kettle, reacted at 150 ℃ for 3 h, and cooled to room temperature with water; (3) The foamed nickel after high-temperature reaction was washed clean with water, dried at 80 ℃ for 10 h, and then put into a tube furnace and heated to 400 ℃ for reaction for 2 h to obtain a self-supporting electrochemical sensing material.

2. Use of a self-supporting electrochemical sensing material produced by the method of claim 1, characterized in that The self-supporting electrochemical sensing material is used for detection of glucose content.

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