Cu-doped nickel sulfide / zinc sulfide composite material, preparation method thereof and application of Cu-doped nickel sulfide / zinc sulfide composite material in enzyme-free glucose detection

Abstract

The invention discloses a Cu-doped nickel sulfide / zinc sulfide composite material, a preparation method thereof and application of the Cu-doped nickel sulfide / zinc sulfide composite material in enzyme-free glucose detection, and belongs to the technical field of preparation and application of composite materials. The preparation method comprises the following steps: pretreating foamed nickel, dissolving nickel nitrate, zinc nitrate hexahydrate, copper nitrate trihydrate and thiourea in deionized water for ultrasonic dispersion, transferring to a high-pressure reaction kettle, putting the pretreated foamed nickel, and washing and drying after reaction to obtain the composite material. The material is of a nanosheet network structure, and the Cu element is uniformly doped. When the material is used as an electrode material for an enzyme-free glucose electrochemical sensor, the sensitivity reaches up to 22.16 mA mM <-1 > cm <-2 >, the response time is only 2 seconds, and the anti-interference performance is high. The problems that an existing enzyme-free glucose sensor electrode material is tedious in preparation, low in sensitivity and the like are solved, raw materials are cheap, operation is easy and convenient, and good application prospects are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation and application of composite materials, in particular to a Cu-doped nickel sulfide / zinc sulfide composite material, a preparation method thereof, and application thereof in enzyme-free glucose detection. Background Art

[0002] Diabetes, as a metabolic disease, seriously affects people's health and safety. The series of complications caused by diabetes, such as heart disease, kidney disease, and blindness, are extremely dangerous. Accurately monitoring the glucose content in the blood of diabetic patients is an effective means to understand and diagnose the patient's condition. At present, electrochemical detection methods are widely used for glucose concentration analysis due to their high effectiveness and low cost. The accuracy of the analysis results mainly depends on the performance of the sensor. Glucose electrochemical sensors are divided into enzyme sensors and non-enzyme sensors. Among them, although enzyme sensors are accurate, they are expensive and easily affected by conditions such as temperature and acidity. Therefore, non-enzyme glucose sensors have been widely studied and promoted.

[0003] Currently, electrodes for non-enzymatic glucose sensors are mostly made of precious metals (such as Pt and Au) or transition metals (Fe, Co, Ni, and Cu). While precious metals are highly active in glucose oxidation, they are expensive, making them unsuitable for large-scale industrial production. Transition metals, on the other hand, are inexpensive and possess excellent electrocatalytic activity and stability. Consequently, a range of transition metal materials and their alloys, such as metal oxides, phosphides, and nitrides, have been developed for use in non-enzymatic glucose sensors. Patent CN113899798 B discloses a method for preparing a non-enzymatic glucose sensor based on a Co and Zn bimetallic organic framework (BOF). This method utilizes a microwave-assisted one-step synthesis method, enabling rapid and convenient glucose detection. While microwave methods allow for rapid synthesis of electrode materials, the overall process is complex, and the resulting sensor's sensitivity needs improvement. Patent CN112345609 B discloses a method for preparing a nano-copper-coated copper foam. The foam is surface-oxidized in an oxygen-containing atmosphere or alkaline solution and used as a non-enzymatic glucose sensor. This sensor exhibits high selectivity, sensitivity, and stability, but has a limited glucose concentration detection range.

[0004] Thus, although some progress has been made in the use of transition metal materials in non-enzymatic glucose sensors, there are still problems such as complex preparation processes, low sensitivity, poor anti-interference, and a small glucose concentration detection range. Therefore, it is of great significance to explore and develop high-efficiency, low-cost, and high-performance transition metal electrode materials for non-enzymatic glucose sensors. Summary of the Invention

[0005] The purpose of the present invention is to provide a Cu-doped nickel sulfide / zinc sulfide composite material, a preparation method and application thereof, and to prepare a copper-doped nickel sulfide / zinc sulfide composite electrode material by a simple and efficient method, and use it in an enzyme-free glucose electrochemical sensor to achieve high sensitivity and strong anti-interference performance, so as to solve the problems of the current enzyme-free glucose electrochemical sensor electrode material proposed in the background technology, such as the complicated preparation process, low sensitivity, poor anti-interference performance and small glucose concentration detection range.

[0006] To achieve the above object, the present invention provides a method for preparing a Cu-doped nickel sulfide / zinc sulfide composite material, comprising the following steps:

[0007] (1) pre-treating nickel foam;

[0008] (2) dissolving nickel nitrate, zinc nitrate hexahydrate, copper nitrate trihydrate, and thiourea in deionized water, and ultrasonically dispersing the mixture to form a uniform mixed solution;

[0009] (3) transferring the mixed solution obtained in step (2) into a stainless steel autoclave lined with a polytetrafluoroethylene liner, and placing two pieces of nickel foam pretreated in step (1) into the autoclave. The autoclave is sealed and placed in an electric constant temperature blast drying oven for reaction;

[0010] (4) After the reaction is completed, the nickel foam is taken out, the precipitate attached to the surface is rinsed with deionized water, and then placed in an electric constant temperature blast drying oven for drying to obtain a nickel foam supported Cu doped-nickel sulfide / zinc sulfide composite material.

[0011] Preferably, the specific operation of step (1) is: cutting the nickel foam into 1 cm×2 cm small pieces, washing them with hydrochloric acid, acetone and ethanol for 10 minutes respectively, and then drying them in an oven at 60°C.

[0012] Preferably, in step (2), the molar volume ratio of nickel nitrate, zinc nitrate hexahydrate, copper nitrate trihydrate, thiourea and deionized water is 0.1 mmol: 0.05 mmol: 0.02 mmol: 0.45 mmol: 30 mL.

[0013] Preferably, in step (3), the reaction temperature is 120° C. and the reaction time is 10 h.

[0014] Preferably, in step (4), the drying temperature is 60°C.

[0015] The present invention also provides a Cu-doped nickel sulfide / zinc sulfide composite material prepared by the above preparation method.

[0016] The present invention also provides the use of the Cu-doped nickel sulfide / zinc sulfide composite material as an electrode material in the preparation of an enzyme-free glucose electrochemical sensor.

[0017] Therefore, the preparation method of the present invention has the advantages of low raw material price and simple operation. The integrated electrode composed of the material and the conductive carrier can be directly used as a working electrode, eliminating the process of coating the material on the working electrode, and is more convenient and reliable to use. The enzyme-free glucose sensor electrode material of the present invention has more excellent electrocatalytic performance, higher sensitivity, lower detection limit, and good anti-interference performance.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the X-ray diffraction pattern of Cu-doped nickel sulfide / zinc sulfide prepared in Example 1 of the present invention;

[0020] Figure 2 This is a scanning electron microscope image of Cu-doped nickel sulfide / zinc sulfide prepared in Example 1 of the present invention, where (a) is 5 μm; (b) is 200 nm;

[0021] Figure 3 Transmission electron microscopy (TEM) images and elemental mapping of Cu-doped nickel sulfide / zinc sulfide prepared in Example 1 of the present invention; (a) 100 nm and (b) 2 nm are TEM images; (e) Ni, (f) Zn, (g) Cu, and (h) S are elemental mapping images;

[0022] Figure 4 Performance graphs of the Cu-doped nickel sulfide / zinc sulfide non-enzymatic glucose sensor prepared in Example 1 of the present invention; (a) is the cyclic voltammetry curve at different glucose concentrations; (b) is the current response curve of Cu-doped nickel sulfide / zinc sulfide to the continuous addition of glucose at a voltage of 0.55 V; (c) is the linear fitting relationship between the response current and concentration of Cu-doped nickel sulfide / zinc sulfide during the electrocatalytic oxidation of glucose; (d) is the response time of Cu-doped nickel sulfide / zinc sulfide;

[0023] Figure 5 The response current of the Cu-doped nickel sulfide / zinc sulfide prepared in Example 1 of the present invention to the interferent;

[0024] Figure 6 Performance graphs of the nickel sulfide / zinc sulfide non-enzymatic glucose sensor prepared in Comparative Example 1 of the present invention; (a) shows the current response of the nickel sulfide / zinc sulfide to the continuous addition of glucose at a voltage of 0.55 V; (b) shows the linear fitting relationship between the response current and concentration of the nickel sulfide / zinc sulfide electrocatalytic oxidation of glucose;

[0025] Figure 7Performance diagram of the copper-doped nickel sulfide non-enzyme glucose sensor prepared in Comparative Example 2 of the present invention; (a) is the current response of nickel sulfide to the continuous addition of glucose at a voltage of 0.55 V; (b) is the linear fitting relationship between the response current and concentration during the electrocatalytic oxidation of glucose by nickel sulfide. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below by means of the accompanying drawings and examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. Any other changes, modifications, substitutions, combinations, and simplifications made without violating the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the protection scope of the present invention. In addition, it should be understood that after reading the contents of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application and belong to the scope of protection of the present invention.

[0027] References to "embodiments" herein mean that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the word "embodiment" in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the various technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution.

[0028] Unless otherwise defined, the technical terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit this application.

[0029] Unless otherwise specified in the present invention, the materials, reagents, instruments, equipment and performance testing methods used are those commonly used by those skilled in the art.

[0030] Example 1

[0031] This embodiment provides a method for preparing a Cu-doped nickel sulfide / zinc sulfide composite material, comprising the following steps:

[0032] (1) Cut the nickel foam into 1 cm × 2 cm pieces, wash them with hydrochloric acid, acetone, and ethanol for 10 min respectively, and then dry them in an oven at 60 °C.

[0033] (2) Dissolve 0.1 mmol of nickel nitrate (Ni(NO3)2), 0.05 mmol of zinc nitrate hexahydrate (Zn(NO3)·6H2O), 0.02 mmol of copper nitrate trihydrate (Cu(NO3)2·3H2O) and 0.45 mmol of thiourea (CH4N2S) in 30 mL of deionized water, and use an ultrasonicator to disperse the mixed solution for 30 min to form a uniform mixed solution.

[0034] (3) The obtained mixed solution was transferred to a 50 mL stainless steel high-pressure reactor with a polytetrafluoroethylene liner, and two pieces of treated nickel foam were placed in the reactor. The reactor was sealed and placed in an electric constant temperature forced air drying oven at 120°C for 10 h.

[0035] (4) After the reaction is completed, the nickel foam is taken out, the precipitate attached to the surface is rinsed with deionized water, and the nickel foam is placed in an electric constant temperature blast drying oven and dried at 60° C. to obtain a nickel foam-supported Cu-doped nickel sulfide / zinc sulfide composite material.

[0036] The crystal structure of the composite material obtained in Example 1 was analyzed by X-ray diffraction. Figure 1 It can be seen that the characteristic diffraction peak of the confirmed material is consistent with the nickel sulfide (Ni3S2, PDF#44-1418) crystal, and zinc sulfide mainly exists in an amorphous crystal state, so its characteristic diffraction peak does not appear.

[0037] from Figure 2 It can be observed that the Cu-doped nickel sulfide / zinc sulfide composite material is a network structure composed of nanosheets. This nanosheet structure is conducive to exposing more material surface area and thus providing more active sites; and the network structure forms a large number of void structures, which is conducive to the penetration of electrolyte and improves ion transport.

[0038] Depend on Figure 3 Transmission electron microscopy analysis of the fine structure reveals that the Cu-doped nickel sulfide / zinc sulfide is composed of amorphous zinc sulfide and nickel sulfide crystals, with lattice spacings of 0.20 nm and 0.29 nm corresponding to the (202) and (110) planes of Ni3S2, respectively. Mapping analysis reveals that the Cu element is uniformly distributed throughout the sample, confirming its doping. Ni, Zn, and S are also uniformly distributed throughout the sample.

[0039] Comparative Example 1

[0040] This comparative example provides a nickel foam-supported nickel sulfide / zinc sulfide composite material, comprising the following steps:

[0041] (1) Cut the nickel foam into 1 cm × 2 cm pieces, wash them with hydrochloric acid, acetone, and ethanol for 10 min respectively, and then dry them in an oven at 60 °C.

[0042] (2) Dissolve 0.1 mmol of nickel nitrate (Ni(NO3)2), 0.05 mmol of zinc nitrate hexahydrate (Zn(NO3)·6H2O) and 0.45 mmol of thiourea (CH4N2S) in 30 mL of deionized water, and use an ultrasonicator to disperse the mixed solution for 30 min to form a uniform mixed solution.

[0043] (3) The obtained mixed solution was transferred to a 50 mL stainless steel high-pressure reactor with a polytetrafluoroethylene liner, and two pieces of treated nickel foam were placed in the reactor. The reactor was sealed and placed in an electric constant temperature forced air drying oven at 120°C for 10 h.

[0044] (4) After the reaction is completed, the nickel foam is taken out, the precipitate attached to the surface is rinsed with deionized water, and the nickel foam is placed in an electric constant temperature blast drying oven and dried at 60° C. to obtain a nickel foam-supported nickel sulfide / zinc sulfide composite material.

[0045] Comparative Example 2

[0046] This comparative example provides a nickel foam-supported Cu-doped nickel sulfide material, comprising the following steps:

[0047] (1) Cut the nickel foam into 1 cm × 2 cm pieces, wash them with hydrochloric acid, acetone, and ethanol for 10 min respectively, and then dry them in an oven at 60 °C.

[0048] (2) Dissolve 0.15 mmol of nickel nitrate (Ni(NO3)2), 0.02 mmol of copper nitrate trihydrate (Cu(NO3)2·3H2O) and 0.45 mmol of thiourea (CH4N2S) in 30 mL of deionized water, and use an ultrasonicator to disperse the mixed solution for 30 min to form a uniform mixed solution.

[0049] (3) The obtained mixed solution was transferred to a 50 mL stainless steel high-pressure reactor with a polytetrafluoroethylene liner, and two pieces of treated nickel foam were placed in the reactor. The reactor was sealed and placed in an electric constant temperature forced air drying oven at 120°C for 10 h.

[0050] (4) After the reaction is completed, the nickel foam is taken out, the precipitate attached to the surface is rinsed with deionized water, and the nickel foam is placed in an electric constant temperature blast drying oven and dried at 60° C. to obtain a Cu-doped nickel sulfide material supported by the nickel foam.

[0051] Application Examples

[0052] The electrode materials prepared in Example 1 and Comparative Examples 1-2 were used to prepare non-enzymatic glucose sensors.

[0053] The non-enzymatic glucose sensor includes a working electrode, a reference electrode, a counter electrode, and an electrolyte. The working electrode is made of the electrode material prepared in Example 1 and Comparative Examples 1-2; the counter electrode is a carbon rod electrode; the reference electrode is a Hg / HgO electrode; and the electrolyte is a 0.5 M sodium hydroxide solution. The non-enzymatic glucose sensor is connected to an electrochemical workstation.

[0054] (1) Sensitivity Test: The current response values ​​of the non-enzymatic glucose sensors based on the electrode materials prepared in Example 1 and Comparative Examples 1-2 to glucose solutions of known concentrations were tested at a specified applied potential. Chronoamperometric curves were plotted based on the current response values ​​corresponding to the glucose concentrations, and the sensitivity was calculated by linear fitting based on the current response values ​​corresponding to the glucose concentrations.

[0055] (2) Anti-interference test: Under an applied voltage of 0.55 V, 0.1 M glucose and 0.01 M other interfering substances (sodium chloride, urea, ascorbic acid, dopamine hydrochloride) were continuously added to a 0.1 M NaOH solution to test the response current of the Cu-doped nickel sulfide / zinc sulfide prepared in Example 1 to the interfering substances, and the IT curve was plotted.

[0056] Depend on Figure 4 (a) shows the cyclic voltammetry curves of a non-enzymatic glucose sensor based on the electrode material prepared in Example 1 at a scan rate of 20 mV / s in electrolytes with varying glucose concentrations. The figure shows that the oxidation peak significantly increases with increasing glucose concentration, and the peak current rises, demonstrating that the material can electrocatalyze glucose oxidation. Figure 4 (b, c) show that the non-enzyme glucose sensor based on the electrode material prepared in Example 1 exhibits a good linear relationship between the response current and concentration during glucose electrocatalytic oxidation. In the linear range of 0-1 mM, the fitted linear equation y = 22.16x + 0.76 is obtained. The sensitivity calculation formula: sensitivity = linear equation slope / electrode area, the sensitivity of the non-enzyme glucose sensor constructed based on the electrode material prepared in Example 1 in the range of 0-1 mM is calculated to be 22.16 mA mM. -1 cm -2 . Figure 4 (d) is an I-T diagram of the electrode material prepared in Example 1 in response to glucose. The response time required for the sensor to transition from the previous stable state to the next stable state is only 2 seconds, indicating that the Cu-doped nickel sulfide / zinc sulfide has a fast response speed to the electrocatalytic oxidation of glucose.

[0057] At a working potential of 0.55 V, 0.1 mM glucose and 0.01 mM interfering substances (including sodium chloride, uric acid, ascorbic acid, and dopamine hydrochloride) were continuously added to a 0.5 M NaOH electrolyte solution that was continuously and evenly stirred to test the response current of the Cu-doped nickel sulfide / zinc sulfide prepared in Example 1 to the interfering substances. Figure 5 It can be clearly seen in the figure that when 0.1mM glucose is first added, Cu-doped nickel sulfide / zinc sulfide has a significant current response, which quickly stabilizes. In contrast, after the addition of the interfering substance, there is no significant response current, and it can even be ignored, indicating that Cu-doped nickel sulfide / zinc sulfide has good anti-toxicity.

[0058] Depend on Figure 6 It can be seen that the enzyme-free glucose sensor based on the electrode material prepared in Comparative Example 1 shows a good linear relationship between the response current and concentration during the electrocatalytic oxidation of glucose. In the linear range of 0-1 mM, the linear equation obtained by fitting is y=18.60x+0.82. According to the sensitivity calculation formula: sensitivity=slope of linear equation / electrode area, the sensitivity of the enzyme-free glucose sensor constructed in Comparative Example 1 in the range of 0-1 mM is calculated to be 18.60 mA mM. -1 cm -2 .

[0059] By Figure 7 It can be seen that the non-enzyme glucose sensor based on the electrode material prepared in Comparative Example 2 shows a good linear relationship between the response current and concentration during the electrocatalytic oxidation of glucose. In the linear range of 0-1 mM, the linear equation obtained by fitting is y=17.99x+0.76. According to the sensitivity calculation formula: sensitivity=slope of linear equation / electrode area, the sensitivity of the non-enzyme glucose sensor constructed in Example 1 in the range of 0-1 mM is calculated to be 17.99 mA mM. -1 cm -2 .

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a Cu-doped nickel sulfide / zinc sulfide composite material, characterized in that: The following steps are involved: (1) pre-treating nickel foam; (2) dissolving nickel nitrate, zinc nitrate hexahydrate, copper nitrate trihydrate, and thiourea in deionized water, and ultrasonically dispersing the mixture to form a uniform mixed solution; (3) transferring the mixed solution obtained in step (2) into a stainless steel autoclave lined with polytetrafluoroethylene, and placing two pieces of nickel foam pretreated in step (1) into the autoclave. The autoclave is sealed and placed in an electric constant temperature blast drying oven for reaction; (4) After the reaction is completed, the nickel foam is taken out, the precipitate attached to the surface is rinsed with deionized water, and then placed in an electric constant temperature blast drying oven for drying to obtain a nickel foam supported Cu doped-nickel sulfide / zinc sulfide composite material.

2. The method for preparing a Cu-doped nickel sulfide / zinc sulfide composite material according to claim 1, wherein: The specific operation of step (1) is as follows: cutting the nickel foam into 1 cm×2 cm small pieces, washing them with hydrochloric acid, acetone and ethanol for 10 minutes respectively, and then drying them in an oven at 60°C.

3. The method for preparing a Cu-doped nickel sulfide / zinc sulfide composite material according to claim 1, wherein: In step (2), the molar volume ratio of nickel nitrate, zinc nitrate hexahydrate, copper nitrate trihydrate, thiourea and deionized water is 0.1 mmol: 0.05 mmol: 0.02 mmol: 0.45 mmol: 30 mL.

4. The method for preparing a Cu-doped nickel sulfide / zinc sulfide composite material according to claim 1, wherein: In step (3), the reaction temperature is 120° C. and the reaction time is 10 h.

5. The method for preparing a Cu-doped nickel sulfide / zinc sulfide composite material according to claim 1, wherein: In step (4), the drying temperature is 60°C.

6. A Cu-doped nickel sulfide / zinc sulfide composite material, characterized in that: The Cu-doped nickel sulfide / zinc sulfide composite material is prepared by the preparation method according to any one of claims 1 to 5.

7. The use of a Cu-doped nickel sulfide / zinc sulfide composite material according to claim 6, characterized in that: The Cu-doped nickel sulfide / zinc sulfide composite material is used as an electrode material for preparing an enzyme-free glucose electrochemical sensor.

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