Cuprous oxide-based ternary composite sensing electrode, its preparation method, and applications

Abstract

This invention provides a cuprous oxide-based ternary composite sensing electrode, comprising a stainless steel substrate on which graphene oxide-doped polyaniline is deposited. The graphene oxide-doped polyaniline possesses a three-dimensional porous network structure, upon which cuprous oxide nanoparticles are deposited. This invention utilizes a two-step electrodeposition method to prepare a Cu₂O-based ternary composite sensing electrode with a well-integrated three-dimensional porous network structure on inexpensive 304 stainless steel. The graphene oxide-doped polyaniline enhances the electrode's conductivity, and its three-dimensional network structure provides abundant active sites for the electrodeposition of Cu₂O nanoparticles. This also significantly increases the electrochemically active area of ​​the sensing electrode, providing rich electronic and ion pathways for the electrocatalysis of biomarkers.

Description

Technical Field

[0001] This invention relates to the field of metal oxide-based electrochemical sensing electrode preparation technology, and more specifically to a cuprous oxide-based ternary composite sensing electrode and its preparation method, as well as its application in the detection of glucose and ascorbic acid. Background Technology

[0002] Glucose participates in numerous reactions within the body and is one of the most important biological compounds. With hundreds of millions of people worldwide suffering from diabetes, monitoring blood glucose levels is crucial. Frequent blood glucose monitoring is essential for optimizing disease management and preventing related problems such as cardiovascular and kidney disease, stroke, blindness, and neurodegeneration.

[0003] Ascorbic acid, commonly known as vitamin C, can improve the body's immune system and prevent cancer and retinal muscle degeneration due to its unique antioxidant properties. In addition, it helps with tissue recovery after surgery and different types of wounds. Ascorbic acid deficiency can lead to scurvy, but excessive ascorbic acid in tissues can also cause kidney stones, nausea, and diarrhea.

[0004] Therefore, it is crucial to design sensitive, simple, accurate, and instantaneous sensors to sense and detect glucose and ascorbic acid in clinical treatment and diagnosis.

[0005] Transition metal oxide-based electrochemical sensors have broad application prospects, especially Cu2O, which exhibits high electrochemical catalytic activity for biomarkers. However, the low conductivity of Cu2O limits its detection performance. Combining Cu2O with conductive polymers or carbon materials can significantly improve its electrocatalytic activity and enhance the detection of biomarkers.

[0006] For example, in the prior art, a porous polyaniline structure prepared by cyclic voltammetry is used as a template to prepare a nano-polyaniline cuprous oxide composite material with a regular polyhedral structure by electrodeposition reaction between the template and an acidic mixed solution of copper salt. However, polyaniline has poor conductivity, and the microstructure of this multi-component nanocomposite material is loose and porous polyaniline loaded with cuprous oxide nanoparticles, which has weak bonding force, thus affecting the performance of the material.

[0007] For example, existing technologies also employ liquid-phase reduction to synthesize and then coating polyaniline-supported cuprous oxide multi-component nanocomposite materials and modified electrodes. However, the electrochemical active material of this electrode has poor bonding force with the substrate, resulting in low sensitivity and narrow detection range for biomarkers. In addition, the electrode preparation process is complex and the preparation cost is high.

[0008] Existing technical documents:

[0009] Chinese Patent: CN108130552

[0010] Chinese Patent: CN113804737 Summary of the Invention

[0011] The purpose of this invention is to address the shortcomings of existing technologies by providing a cuprous oxide-based ternary composite sensing electrode and its preparation method. A Cu2O-based ternary composite sensing electrode with a well-bonded three-dimensional porous network structure, where the electrochemically active material and the substrate are well integrated, is prepared on inexpensive 304 stainless steel using a two-step electrodeposition method. Graphene oxide doping with polyaniline improves the electrode's conductivity, and its three-dimensional network structure provides abundant active sites for Cu2O nanoparticle electrodeposition. This also significantly increases the electrochemically active area of ​​the sensing electrode, providing rich electronic and ion pathways for the electrocatalysis of biomarkers.

[0012] The first aspect of the present invention relates to a cuprous oxide-based ternary composite sensing electrode, the electrode comprising a stainless steel substrate, wherein graphene oxide-doped polyaniline is deposited on the surface of the stainless steel substrate, wherein the graphene oxide-doped polyaniline has a three-dimensional porous network structure, and cuprous oxide nanoparticles are deposited on the three-dimensional porous network structure.

[0013] In an optional embodiment, the diameter of a single polyaniline nanofiber is 30~50 nm.

[0014] In an optional embodiment, the particle size of the cuprous oxide nanoparticles ranges from 100 to 200 nm.

[0015] The second aspect of this invention relates to a method for preparing the aforementioned cuprous oxide-based ternary composite sensing electrode, comprising:

[0016] First, a three-dimensional porous network structure of graphene oxide (GO)-doped polyaniline (PANI) was electrochemically synthesized on a stainless steel (SS) substrate.

[0017] Then, cuprous oxide (Cu2O) nanoparticles were deposited on the three-dimensional porous network structure using a potentiostatic method to obtain the Cu2O / PANI-GO / SS electrode.

[0018] In an optional embodiment, the electrochemical synthesis uses a mixed solution of H2SO4 and aniline (ANI) as the first electrolyte solution, and graphene oxide (GO) is added to the electrolyte.

[0019] In an optional embodiment, the electrochemical synthesis conditions are as follows: the molar ratio of H2SO4 to ANI in the first electrolyte solution is (10:1) to (30:1); the volume ratio of the first electrolyte solution to the GO aqueous solution is (5:1) to (20:1); the contents of H2SO4 and ANI are 0.5 to 2.0 mM and 0.025 to 0.1 mM, respectively, and the GO concentration is 0.5 to 4 mg / mL; the deposition temperature is 30°C, the deposition potential is 0.8 to 1.0 V, and the deposition time is 200 to 400 s.

[0020] In an optional implementation, the potentiostatic method uses a mixture of copper sulfate (CuSO4) and lactic acid solution as the second electrolyte solution.

[0021] In an optional embodiment, the molar ratio of lactic acid to CuSO4 in the second electrolyte solution is (15:1) to (3:1); the contents of lactic acid and CuSO4 are 1.5 to 4.5 mM and 0.2 to 0.6 mM, respectively; the pH of the second electrolyte solution is 9 to 11; the deposition temperature is 60°C; the deposition potential is -0.3 to -0.5 V; and the deposition time is 120 to 300 s.

[0022] The third aspect of the present invention relates to the application of the aforementioned cuprous oxide-based ternary composite sensing electrode in the detection of glucose and ascorbic acid.

[0023] In an optional embodiment, Cu2O / PANI-GO / SS is used as the working electrode, Pt sheet as the counter electrode, and saturated calomel electrode (SCE) as the reference electrode. Different concentrations of glucose or ascorbic acid are continuously added to 0.1M NaOH aqueous solution to perform amperometric response testing, with a voltage of 0.40-0.65V.

[0024] Compared with the prior art, the significant advantages of the present invention are as follows:

[0025] The cuprous oxide-based ternary composite sensing electrode of the present invention uses inexpensive 304 stainless steel as the substrate material and is prepared by a two-step electrodeposition method to obtain a ternary composite sensing electrode Cu2O / PANI-GO / SS in which the electrochemical active material is well bonded to the substrate. The graphene oxide-doped PANI has good conductivity and a composite three-dimensional porous network structure. The composite three-dimensional porous network structure provides abundant active sites for the electrodeposition of Cu2O nanoparticles, and also greatly increases the electrochemical active area of ​​the sensing electrode, providing abundant electronic and ion pathways for the electrocatalysis of glucose and ascorbic acid. Therefore, it has good prospects in the detection of glucose and ascorbic acid.

[0026] The preparation method of this invention is low in cost and simple to implement, and has great application potential in fields that require rapid quantitative determination of glucose and ascorbic acid. Attached Figure Description

[0027] Figure 1 This is a scanning electron microscope image of the PANI-GO / SS electrode as an example of the present invention.

[0028] Figure 2 This is a scanning electron microscope image of the PANI-GO / SS electrode as an example of the present invention.

[0029] Figure 3 This is a scanning electron microscope image of the Cu2O / PANI-GO / SS electrode as an example of the present invention.

[0030] Figure 4 This is a transmission electron microscope (TEM) image of the Cu2O / PANI-GO / SS electrode as an example of the present invention.

[0031] Figure 5 This is an X-ray energy spectrum of the Cu2O / PANI-GO / SS electrode of the present invention; wherein, a is C element; b is Cu element; c is O element; and d is N element.

[0032] Figure 6 The current response of the Cu2O / PANI-GO / SS electrode of this invention at 0.65V when glucose is continuously added to 0.1M NaOH is shown.

[0033] Figure 7 This is the corresponding calibration curve of the Cu2O / PANI-GO / SS electrode of this invention in response to glucose current.

[0034] Figure 8 The current response of the Cu2O / PANI-GO / SS electrode of this invention at 0.60V with continuous addition of ascorbic acid to 0.1M NaOH is shown.

[0035] Figure 9 The corresponding calibration curves for the Cu2O / PANI-GO / SS electrode of this invention in response to ascorbic acid current are shown. Detailed Implementation

[0036] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0037] Various aspects of the invention are described in this disclosure with reference to the accompanying drawings, in which numerous illustrative embodiments are shown. The embodiments of this disclosure are not necessarily intended to encompass all aspects of the invention. It should be understood that the various concepts and embodiments described above, as well as those described below in more detail, can be implemented in any of a number of ways.

[0038] In an exemplary embodiment of the present invention, a cuprous oxide-based ternary composite sensing electrode is provided. The electrode includes a stainless steel substrate, on the surface of which graphene oxide-doped polyaniline is deposited. The graphene oxide-doped polyaniline has a three-dimensional porous network structure, and cuprous oxide nanoparticles are deposited on the three-dimensional porous network structure.

[0039] In an optional embodiment, the diameter of a single polyaniline nanofiber is 30~50 nm.

[0040] In an optional embodiment, the particle size of the cuprous oxide nanoparticles ranges from 100 to 200 nm.

[0041] In another exemplary embodiment of the present invention, a method for preparing the aforementioned cuprous oxide-based ternary composite sensing electrode is provided, comprising:

[0042] First, a three-dimensional porous network structure of graphene oxide (GO)-doped polyaniline (PANI) was electrochemically synthesized on a stainless steel (SS) substrate.

[0043] Then, cuprous oxide (Cu2O) nanoparticles were deposited on the three-dimensional porous network structure using a potentiostatic method to obtain the Cu2O / PANI-GO / SS electrode.

[0044] In one typical embodiment, the preparation method of the cuprous oxide-based ternary composite sensing electrode includes the following specific steps:

[0045] Step 1: Using H2SO4, ANI and GO as electrolyte solutions, a composite three-dimensional porous network structure of graphene oxide doped with polyaniline was electrochemically synthesized on 304 stainless steel.

[0046] Step 2: The electrode obtained in Step 1 is deionized and then dried in a vacuum drying oven to obtain the PANI-GO / SS electrode;

[0047] Step 3: Place the PANI-GO / SS electrode obtained in Step 2 in CuSO4 and lactic acid solution, and deposit Cu2O nanoparticles using a potentiostatic method.

[0048] Step 4: The electrode obtained in Step 3 is deionized and dried at room temperature for 12 hours to finally obtain the ternary composite sensing electrode Cu2O / PANI-GO / SS.

[0049] In a further embodiment, in step 1, the molar ratio of H2SO4 to ANI in the electrolyte solution is (10:1) to (30:1); the volume ratio of the electrolyte solution to the GO aqueous solution is (5:1) to (20:1); the contents of H2SO4 and ANI are 0.5 to 2.0 mM and 0.025 to 0.1 mM, respectively, and the GO concentration is 0.5 to 4 mg / mL; the deposition temperature is 30°C, the deposition potential is 0.8 to 1.0 V, and the deposition time is 200 to 400 s.

[0050] In a further embodiment, in step 2, the deionization cleaning is performed three times, followed by drying in a vacuum drying oven at a temperature of 30-50 ℃ for 5-8 h.

[0051] In a further embodiment, in step 3, the molar ratio of lactic acid to CuSO4 in the electrolyte solution is (15:1) to (3:1); the contents of lactic acid and CuSO4 are 1.5 to 4.5 mM and 0.2 to 0.6 mM, respectively; the pH of the electrolyte solution is 9 to 11; the deposition temperature is 60°C; the deposition potential is -0.3 to -0.5 V; and the deposition time is 120 to 300 s.

[0052] In a further embodiment, in step 3, the deionization cleaning is performed three times, followed by drying at room temperature.

[0053] In a further embodiment, the pretreatment method for the 304 stainless steel substrate is as follows:

[0054] Cut stainless steel to a size of 10×15×0.01mm. First, ultrasonically clean it in anhydrous ethanol for 5-10 minutes, then ultrasonically clean it in deionized water for 5-10 minutes. After ultrasonic cleaning, dry it in a vacuum drying oven and store it in a vacuum bag for later use.

[0055] In another exemplary embodiment of the present invention, the application of the aforementioned cuprous oxide-based ternary composite sensing electrode in the detection of glucose and ascorbic acid is also provided.

[0056] In an optional embodiment, Cu2O / PANI-GO / SS is used as the working electrode, Pt sheet as the counter electrode, and saturated calomel electrode (SCE) as the reference electrode. Different concentrations of glucose or ascorbic acid are continuously added to 0.1M NaOH aqueous solution to perform amperometric response testing, with a voltage of 0.40-0.65V.

[0057] The following examples illustrate the above preparation process and the prepared cuprous oxide-based ternary composite sensing electrode through experimental testing.

[0058] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0059] Example 1

[0060] Electrochemical synthesis of PANI-GO / SS electrodes

[0061] Stainless steel with a cutting specification of 10×15×0.01mm was first ultrasonically cleaned in anhydrous ethanol for 5 minutes, then ultrasonically cleaned in deionized water for 5 minutes. After ultrasonic cleaning, it was placed in a vacuum drying oven to dry and stored in a vacuum bag for later use.

[0062] Prepare 22 mL of electrolyte solution: the molar ratio of H2SO4 to ANI is 20:1, the contents of H2SO4 and ANI are 1.0 mM and 0.05 mM, respectively, the concentration of GO in the electrolyte is 2 mg / mL, and the volume is 2 mL.

[0063] Deposition was performed at a constant voltage at an ambient temperature of 30 °C, with a deposition potential of 0.3 V and a deposition time of 300 s.

[0064] The electrode was then washed three times with deionized water and dried in a vacuum drying oven at 40 ℃ for 6 h to obtain the PANI-GO / SS electrode. Figure 1 and Figure 2 As shown.

[0065] from Figure 1 and Figure 2 It can be seen that the PANI-GO / SS electrode has a three-dimensional porous network structure, and the diameter of a single polyaniline nanofiber is about 30~50nm, which can provide abundant active sites for Cu2O nanoparticle electrodeposition, and at the same time greatly increase the electrochemical active area of ​​the sensing electrode.

[0066] Example 2

[0067] Cu2O / PANI-GO / SS electrodes were prepared by electrodeposition.

[0068] The PANI-GO / SS electrode obtained according to the method in Example 1 was used as the working electrode, the Pt sheet (10×10×2mm) was used as the counter electrode, and Ag / AgCl was used as the reference electrode.

[0069] In 20 mL of electrolyte, the molar ratio of lactic acid to CuSO4 was 15:2, with lactic acid and CuSO4 concentrations of 3 mM and 0.4 mM, respectively. The electrolyte pH was 10. Deposition was then carried out at a constant potential at an ambient temperature of 60 °C, with a deposition potential of -0.4 V and a deposition time of 180 s, resulting in a three-dimensional network composite ternary Cu2O / PANI-GO / SS electrode. Figure 3 and Figure 4 As shown.

[0070] from Figure 3 It can be seen that in the Cu2O / PANI-GO / SS electrode, Cu2O nanoparticles are densely and uniformly anchored on the composite three-dimensional porous network structure of graphene oxide-doped PANI, and combined with... Figure 4 It can be seen that the particle size range of cuprous oxide nanoparticles is 100~200nm.

[0071] Combination Figure 5 The X-ray energy dispersive spectroscopy of the Cu2O / PANI-GO / SS electrode proves the successful deposition of Cu2O nanoparticles, and also shows that graphene oxide is uniformly doped in PANI in the three-dimensional porous network structure of the PANI-GO / SS electrode composite.

[0072] Therefore, it can be proven that the present invention has successfully prepared a cuprous oxide-based ternary composite sensing electrode.

[0073] Example 3

[0074] The ternary composite Cu₂O / PANI-GO / SS electrode obtained according to the method in Example 2 was used as the working electrode, a Pt sheet (10×10×2mm) as the counter electrode, and Ag / AgCl as the reference electrode. Glucose was gradually added dropwise to a continuously stirred NaOH solution at a working potential of 0.65 V. The electrocatalytic performance of the ternary composite Cu₂O / PANI-GO / SS electrode for glucose was demonstrated by detecting the change in current response over time. The change in current response over time is shown in the figure below. Figure 6 As shown, the linear relationship between current and glucose concentration is as follows: Figure 7 As shown.

[0075] The results showed that, at a glucose concentration of 1.0 mM, the linear calibration of the chronoamperometry was divided into two regions. Within the concentration range of 0.01 mM to 3.5 mM, the sensitivity of the Cu2O / PANI-GO / SS electrode was 1832 μA cm⁻¹. -2 mM -1 and 2666.5 μA cm -2 mM -1 The limit of detection (LOD) is 0.59 μM.

[0076] Example 4

[0077] The ternary composite Cu₂O / PANI-GO / SS electrode obtained according to the method in Example 2 was used as the working electrode, a Pt sheet (10×10×2mm) as the counter electrode, and Ag / AgCl as the reference electrode. Ascorbic acid was gradually added dropwise to a continuously stirred NaOH solution at a working potential of 0.60 V. The electrocatalytic performance of the ternary composite Cu₂O / PANI-GO / SS electrode against ascorbic acid was demonstrated by detecting the change in current response over time. The change in current response over time is shown in the figure below. Figure 8 As shown, the linear relationship between current and ascorbic acid is as follows: Figure 9 As shown.

[0078] The results show that the Cu2O / PANI-GO / SS electrode exhibits a capacitance of 1989 µA / cm² at low concentrations ranging from 5 µM to 2 mM. -2 mM -1 Its high sensitivity, exhibiting 987 µA / cm² at concentrations ranging from 2 mM to 11 mM. -2 mM -1 The sensitivity of Cu2O / PANI-GO / SS is also high. Furthermore, the limit of detection (LOD) for ascorbic acid detection is 1.05 µM.

[0079] As can be seen from the above, the Cu2O / PANI-GO / SS electrode of the present invention has high sensitivity and low detection limit for glucose and ascorbic acid, and has excellent performance in the detection of glucose and ascorbic acid. Therefore, it has great application potential in fields that require rapid quantitative detection of glucose and ascorbic acid.

[0080] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A cuprous oxide-based ternary composite sensing electrode, characterized in that, The electrode includes a stainless steel substrate, on the surface of which graphene oxide-doped polyaniline is deposited, wherein the graphene oxide-doped polyaniline has a three-dimensional porous network structure, and cuprous oxide nanoparticles are deposited on the three-dimensional porous network structure. The preparation method of the cuprous oxide-based ternary composite sensing electrode includes: First, a three-dimensional porous network structure of polyaniline (PANI) doped with graphene oxide (GO) was electrochemically synthesized on a stainless steel (SS) substrate. The electrochemical synthesis used a mixed solution of H₂SO₄ and aniline (ANI) as the first electrolyte solution, with graphene oxide (GO) added to the electrolyte. In the first electrolyte solution, the molar ratio of H₂SO₄ to ANI was (10:1) to (30:1); the volume ratio of the first electrolyte solution to the GO aqueous solution was (5:1) to (20:1); the contents of H₂SO₄ and ANI were 0.5–2.0 mM and 0.025–0.1 mM, respectively, and the GO concentration was 0.5–4 mg / mL. The deposition temperature was 30 °C, the deposition potential was 0.8–1.0 V, and the deposition time was 200–400 s. Then, cuprous oxide (Cu2O) nanoparticles were deposited on a three-dimensional porous network structure using a potentiostatic method to obtain a Cu2O / PANI-GO / SS electrode. In the potentiostatic method, a mixed solution of copper sulfate (CuSO4) and lactic acid solution was used as the second electrolyte solution. In the second electrolyte solution, the molar ratio of lactic acid to CuSO4 was (15:1) to (3:1). The contents of lactic acid and CuSO4 were 1.5 to 4.5 mM and 0.2 to 0.6 mM, respectively. The pH of the second electrolyte solution was 9 to 11. The deposition temperature was 60℃, the deposition potential was -0.3 to -0.5 V, and the deposition time was 120 to 300 s.

2. The cuprous oxide-based ternary composite sensing electrode according to claim 1, characterized in that, The diameter of a single polyaniline nanofiber is 30~50nm.

3. The cuprous oxide-based ternary composite sensing electrode according to claim 1, characterized in that, The particle size range of cuprous oxide nanoparticles is 100~200 nm.

4. The application of a cuprous oxide-based ternary composite sensing electrode according to any one of claims 1-3 in the detection of glucose or ascorbic acid.

5. The application according to claim 4, characterized in that, Using Cu2O / PANI-GO / SS as the working electrode, a Pt sheet as the counter electrode, and a saturated calomel electrode (SCE) as the reference electrode, amperometric response tests were conducted by continuously adding different concentrations of glucose or ascorbic acid to a 0.1M NaOH aqueous solution, with voltages ranging from 0.40 to 0.65V.

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