A composite electrode based on conductive hydrogel-tian blue nanoparticles and a preparation method and application thereof

Abstract

The application discloses a kind of based on conductive hydrogel-Teng's blue nanoparticle composite electrode and its preparation method and application, belong to biological electronic material technical field, the method is first by electroplating, vapor deposition or chemical deposition method in the surface of conductive substrate modification iron film, obtain the conductive substrate with iron film;Again using standard three-electrode electrochemical system, with the iron film of conductive substrate as working electrode, immerse into the mixed solution of K3 [Fe (CN) 6 ] and PEDOT:PSS, or immerse into the mixed solution of K3 [Fe (CN) 6 ] and MXene, again using constant current technology or constant voltage technology makes working electrode release Fe 2+ , preparation obtains based on conductive hydrogel-Teng's blue nanoparticle composite electrode.The method step of the application is simple, can synthesize conductive hydrogel and Teng's blue nanoparticle simultaneously, and the catalytic efficiency of composite electrode prepared is good, and can be used for high sensitive detection of H2O2.

Description

Technical Field

[0001] This invention belongs to the field of bioelectronic materials technology, specifically relating to a composite electrode based on conductive hydrogel-Tunnel blue nanoparticles, its preparation method, and its application. Background Technology

[0002] Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) possesses advantages such as good conductivity, high flexibility, stretchability, and good environmental stability, and is currently widely used in the manufacture of various sensing devices, including strain sensors, pressure sensors, temperature sensors, and biosensors. MXene materials have a large specific surface area, high conductivity, good electrolyte wettability, and strong tensile and compressive strength, and are often used as electrode materials for supercapacitors. PEDOT:PSS or MXene can form hydrogels in the presence of sufficiently high concentrations of metal cations. The electrochemical oxidation of the sacrificial metal layer can be used to achieve spatial control of ionic strength. By electroplating a sacrificial metal film on the working electrode and applying a sufficient anodic bias, the sacrificial metal on the working electrode is oxidized into metal cations. These cations diffuse into the electrolyte, inducing gelation of PEDOT:PSS or MXene on the surface of the working electrode.

[0003] As a typical marker of oxidative stress, changes in intracellular hydrogen peroxide levels are directly related to the development of numerous disease-related pathophysiological symptoms, including diabetes, arteriosclerosis, nephrosclerosis, kidney disease, cancer, and aging. Besides being a marker of oxidative stress, H2O2 is also a valuable marker in inflammatory processes and a mediator of apoptotic cell necrosis. Prussian blue (PB), Fe4[Fe(CN)6]3, as a "man-made peroxidase," exhibits high electrocatalytic activity towards H2O2 and is frequently used in the development of H2O2 sensors. Thunberg blue (TB), Fe3[Fe(CN)6]2, has the same crystal structure as Prussian blue and also exhibits catalytic activity towards H2O2.

[0004] Chinese patent document CN111912883A discloses a PEDOT:PSS visual chemiluminescent sensor for detecting gaseous hydrogen peroxide. This invention prepares a PEDOT:PSS-organic acid titanium dioxide film on a substrate via spin coating, and then prepares a PEDOT film by electrochemical polymerization on the PEDOT:PSS-organic acid titanium dioxide film using a chronoamperometry method, thus obtaining the PEDOT:PSS visual chemiluminescent sensor. This sensor can achieve dual effective detection of the electrical signal and visualization of gaseous H2O2. Chinese patent document CN115068673A discloses a method for preparing an MXene-based self-catalytic conductive hydrogel dressing and its application. This method first prepares Ag / TA@MXene nanosheets with catalytic activity, and then prepares a conductive hydrogel at room temperature using acrylic monomers, gelatin, initiators, crosslinking agents, and Ag / TA@MXene nanosheets. The corresponding conductive hydrogel can be used to make a strain sensor, which has application prospects in personalized medical testing and signal monitoring. However, the above methods involve rather complicated experimental procedures, and the quality stability of the products needs to be further improved.

[0005] To achieve high-response H2O2 detection, it is necessary to develop a composite electrode combining conductive hydrogel and Tennant blue. Summary of the Invention

[0006] This invention provides a method for preparing a composite electrode based on conductive hydrogel-Tunnel blue nanoparticles. The method is simple and can simultaneously synthesize conductive hydrogel and Tunnel blue nanoparticles. The conductive hydrogel is uniformly modified with Tunnel blue nanoparticles. The prepared composite electrode has good catalytic efficiency and can be used for highly sensitive detection of H2O2.

[0007] The specific technical solution adopted is as follows:

[0008] A method for preparing a composite electrode based on conductive hydrogel-Tunnel Blue nanoparticles includes the following steps:

[0009] (1) An iron film is modified on the surface of a conductive substrate by electroplating, vapor deposition or chemical deposition to obtain a conductive substrate with an iron film.

[0010] (2) A standard three-electrode electrochemical system was adopted, using a conductive substrate with an iron film as the working electrode. The working electrode was immersed in a mixed solution of K3[Fe(CN)6] and PEDOT:PSS, or a mixed solution of K3[Fe(CN)6] and MXene. Then, constant current or constant voltage technology was used to release Fe from the working electrode. 2+ The composite electrode based on conductive hydrogel-Tunnel blue nanoparticles is prepared by ion gelation and generation of nanoparticles.

[0011] This invention first modifies a conductive substrate with an iron film, and then uses constant current or constant voltage technology to oxidize the iron film on the conductive substrate, releasing Fe. 2+ Metal ions can shield the electrostatic repulsion between microgel particles, causing the particles to aggregate and form a physically cross-linked gel stable by π-π stacking interactions. Therefore, Fe... 2+ PEDOT:PSS or MXene can be induced on the surface of the working electrode and react with [Fe(CN)6]. 3- The reaction forms Fe3[Fe(CN)6]2 (i.e., Tennant Blue, TB), which is then immobilized on PEDOT:PSS hydrogel or MXene hydrogel, forming a composite electrode based on conductive hydrogel-Ttenant Blue nanoparticles. On the one hand, the porous structure of PEDOT:PSS hydrogel or MXene hydrogel can create a larger relative surface area for the sensor surface, and TB can provide catalytic efficiency for H2O2, which is beneficial to the high sensitivity detection of H2O2 by the composite electrode. On the other hand, the one-step modification of the working electrode surface with conductive hydrogel-Ttenant Blue nanoparticles reduces the synthesis steps, improves efficiency, and enables uniform distribution of TB in the conductive hydrogel.

[0012] In step (1), the conductive substrate material includes gold or carbon.

[0013] Since electroplating methods offer better controllability, preferably, in step (1), an iron film is modified on the surface of a conductive substrate by electroplating. The steps include: using a standard three-electrode electrochemical system, with an Ag / AgCl electrode as the reference electrode, a Pt electrode as the counter electrode, a conductive substrate as the working electrode, and a sulfuric acid solution containing FeCl2, sodium dodecyl sulfate, and ascorbic acid as the electroplating solution, and using constant current technology to modify an iron film on the surface of the conductive substrate to obtain a conductive substrate with an iron film.

[0014] More preferably, when using constant current technology, the current density is -6 to -15 A / dm³. 2 Hold for 10–50 seconds.

[0015] More preferably, in the electroplating solution, the concentration of FeCl2 is 40 mg / mL, the concentration of sodium dodecyl sulfate is 0.1 mg / mL, the concentration of ascorbic acid is 1 mg / mL, and the concentration of sulfuric acid is 0.065 M.

[0016] Under the conditions of preferred current value and electroplating solution ratio, a smooth and stable iron film is formed on the surface of a conductive substrate using a constant current plating method.

[0017] Preferably, in step (2), a standard three-electrode electrochemical system is used, with an Ag / AgCl electrode as the reference electrode, a Pt electrode as the counter electrode, and a conductive substrate with an iron film as the working electrode.

[0018] Preferably, in step (2), when using constant voltage technology, the voltage is 0.5 to 1V and is maintained for 20 to 100 seconds.

[0019] Preferably, in the mixed solution of K3[Fe(CN)6] and PEDOT:PSS, the concentration of K3[Fe(CN)6] is 1-10 mM and the mass concentration of PEDOT:PSS is 5-15 wt%.

[0020] Preferably, in the mixed solution of K3[Fe(CN)6] and MXene, the concentration of K3[Fe(CN)6] is 1-10 mM and the concentration of MXene is 5-10 mg / ml.

[0021] The present invention also provides a composite electrode based on conductive hydrogel-Tunnel blue nanoparticles prepared by the method described above.

[0022] The present invention also provides the application of the composite electrode based on conductive hydrogel-Tunnel blue nanoparticles in H2O2 detection. Experiments have shown that when using the composite electrode to detect H2O2 by time-current method, the response is high and the detection effect is good.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] This invention uses a conductive substrate with an iron film as the working electrode and employs a one-step method to modify the surface of the working electrode with PEDOT:PSS-TB composite hydrogel or MXene-TB composite hydrogel. Compared with the existing technology of first modifying the surface of the working electrode with PEDOT:PSS hydrogel or MXene hydrogel and then coating or electroplating with materials such as PB, this invention reduces the number of synthesis steps, improves working efficiency, achieves uniform distribution of TB in PEDOT:PSS hydrogel or MXene hydrogel, and the performance of the final composite electrode can be controlled by adjusting the concentration of PEDOT:PSS / MXene and K3[Fe(CN)6] to achieve high-response H2O2 detection. Attached Figure Description

[0025] Figure 1 The images shown are scanning electron microscope images of the composite electrodes prepared in Comparative Example 1 and Example 1 after lyophilization, where a and c are Comparative Example 1, and b and d are Example 1.

[0026] Figure 2The images show surface element scans of the composite electrodes prepared in Comparative Example 1 and Example 1, where a represents Comparative Example 1 and b represents Example 1.

[0027] Figure 3 The image shows a comparison of the cyclic voltammetry curves of the composite electrodes prepared in Comparative Example 1 and Example 1, where a represents Comparative Example 1 and b represents Example 1.

[0028] Figure 4 The image shows the response of the composite electrode prepared in Example 1 to H2O2 concentration and its fitting curve. Detailed Implementation

[0029] The present invention will be further illustrated below with reference to the embodiments and accompanying drawings. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Operating methods not specifically specified in the following embodiments are generally performed under conventional conditions or as recommended by the manufacturer.

[0030] Example 1

[0031] (1) Clean the gold wire substrate. Use the gold wire substrate as the working electrode, the Ag / AgCl electrode as the reference electrode, and the Pt electrode as the counter electrode to form a standard three-electrode electrochemical system. Immerse the three-electrode electrochemical system in 10 mL of a 0.065 M sulfuric acid solution containing 0.4 g FeCl2, 1 mg sodium dodecyl sulfate, and 10 mg ascorbic acid. Apply a current density of -15 A / dm² to the gold wire substrate. 2 A constant current was applied for 15 seconds to modify an iron film on the surface of a gold wire substrate, resulting in a gold wire substrate with an iron film.

[0032] (2) Then, a standard three-electrode electrochemical system (a gold wire substrate with an iron film as the working electrode, an Ag / AgCl electrode as the reference electrode, and a Pt electrode as the counter electrode) was immersed in a mixed solution of K3[Fe(CN)6] and PEDOT:PSS. The concentration of K3[Fe(CN)6] in the mixed solution was 5 mM, and the mass concentration of PEDOT:PSS was 7 wt%. A positive voltage of 0.9 V was applied for 50 s to allow the working electrode to release Fe. 2+ Fe 2+ Induces gelation of PEDOT:PSS and interacts with [Fe(CN)6] 3- The reaction forms Fe3[Fe(CN)6]2, yielding the composite electrode based on conductive hydrogel-Tunnel blue nanoparticles.

[0033] Comparative Example 1

[0034] (1) Clean the gold wire substrate. Use the gold wire substrate as the working electrode, the Ag / AgCl electrode as the reference electrode, and the Pt electrode as the counter electrode to form a standard three-electrode electrochemical system. Immerse the three-electrode electrochemical system in 10 mL of a 0.065 M sulfuric acid solution containing 0.4 g FeCl2, 1 mg sodium dodecyl sulfate, and 10 mg ascorbic acid. Apply a current density of -15 A / dm² to the gold wire substrate. 2 A constant current was applied for 15 seconds to modify an iron film on the surface of a gold wire substrate, resulting in a gold wire substrate with an iron film.

[0035] (2) Then, the standard three-electrode electrochemical system (a gold wire substrate with an iron film as the working electrode, an Ag / AgCl electrode as the reference electrode, and a Pt electrode as the counter electrode) was immersed in a 7wt% PEDOT:PSS solution, and a positive voltage of 0.9V was applied for 50s to allow the working electrode with the iron film to release Fe. 2+ Fe 2+ The gelation of PEDOT:PSS was induced to obtain a composite electrode based on PEDOT:PSS hydrogel.

[0036] Example 2

[0037] The only difference between this embodiment and the method in Embodiment 1 is that in step (2), when using constant voltage technology, the voltage is 0.5V to prepare the composite electrode based on conductive hydrogel-Teng's blue nanoparticles.

[0038] Example 3

[0039] The only difference between this embodiment and the method in Embodiment 1 is that, in step (1), when using constant current technology, -15A / dm 2 The current density is maintained for 50s. In step (2), when using constant voltage technology, a positive voltage of 0.9V is applied for 100s to prepare the composite electrode based on conductive hydrogel-Teng's blue nanoparticles.

[0040] Example 4

[0041] The difference between this embodiment and the method in Embodiment 1 is only that in step (2), the standard three-electrode electrochemical system (a gold wire substrate with an iron film as the working electrode, an Ag / AgCl electrode as the reference electrode, and a Pt electrode as the counter electrode) is immersed in a mixed solution of K3[Fe(CN)6] and MXene. In the mixed solution, the concentration of K3[Fe(CN)6] is 5 mM and the concentration of MXene is 10 mg / ml, thus preparing the composite electrode based on conductive hydrogel-Tunnel blue nanoparticles.

[0042] Example 5

[0043] The difference between this embodiment and the method in Embodiment 1 is only that in step (2), the concentration of K3[Fe(CN)6] in the mixed solution of K3[Fe(CN)6] and PEDOT:PSS is 2.5 mM and the mass concentration of PEDOT:PSS is 5 wt%, thus preparing the composite electrode based on conductive hydrogel-Tunnel blue nanoparticles.

[0044] Sample Analysis

[0045] Figure 1 The images shown are scanning electron microscope (SEM) images of the lyophilized composite electrodes prepared in Comparative Example 1 and Example 1, where a and c are from Comparative Example 1, and b and d are from Example 1. It can be seen that in the composite electrode based on conductive hydrogel-Tunneling blue nanoparticles synthesized in Example 1, TB particles are attached to the surface of the PEDOT:PSS-TB composite hydrogel, while no TB particles were detected in Comparative Example 1.

[0046] Figure 2 The images show the surface elemental scans of the composite electrodes prepared in Comparative Example 1 and Example 1, where a represents Comparative Example 1 and b represents Example 1. It can be seen that the PEDOT:PSS-TB composite hydrogel synthesized in Example 1 contains a large amount of S, Fe, and N elements. S is a characteristic element of PEDOT-PSS, while Fe and N are characteristic elements of TB. In contrast, the PEDOT:PSS hydrogel in Comparative Example 1 contains a large amount of S and a small amount of Fe, with less N, indicating the successful synthesis of TB nanoparticles.

[0047] Using an Ag / AgCl electrode as the reference electrode and a Pt electrode as the counter electrode, the composite electrodes prepared in Comparative Example 1 and Example 1 were used as working electrodes. Cyclic voltammetry scans were performed in 0.01M PBS (pH = 7.2–7.4, containing 0.1M KCl), with a scan range of -0.5V to 0.5V; scan number: 5 (the 5th scan was used); scan rate: 50mV / s; the obtained cyclic voltammetry curves are shown below. Figure 3 As shown in the figure, a is Comparative Example 1 and b is Example 1. It can be seen from the figure that the cyclic voltammetry curve of Example 1 has an additional pair of redox peaks compared to Comparative Example 1, namely the characteristic peak of TB. This indicates that by adding potassium ferricyanide to the PEDOT:PSS dispersion in Example 1, TB can be formed at the same time as the hydrogel is formed.

[0048] Using an Ag / AgCl electrode as the reference electrode and a Pt electrode as the counter electrode, the composite electrode prepared in Example 1 was used as the working electrode. It was placed in 0.01M PBS (pH = 7.2–7.4, containing 0.1M KCl). A constant voltage of -0.1V was applied to the working electrode, and after stabilizing for 1000 s, 10 μM H₂O₂ was added to the PBS buffer multiple times. The stable current at different H₂O₂ concentrations was measured, and the absolute values ​​were plotted. Figure 4 The current-H2O2 concentration standard curve shows that the change in current is positively correlated with the concentration of added H2O2. The higher the concentration of H2O2 in the test system, the greater the absolute value of the current.

[0049] Figure 4 The results show that the composite electrode prepared in Example 1 has a detection capability of 295.1 mA M for H2O2 in the range of 0–50 μM. -1 cm -2 It exhibits high sensitivity among similar sensors using Prussian blue as a catalyst, and this sensitivity can be further improved by adjusting the preparation conditions.

[0050] The composite electrodes based on conductive hydrogel-Tunnel blue nanoparticles prepared in Examples 2-5 have similar performance to the composite electrode in Example 1.

[0051] The embodiments described above provide a detailed explanation of the technical solutions of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a composite electrode based on conductive hydrogel-Tunnel Blue nanoparticles, characterized in that, Includes the following steps: (1) An iron film is modified on the surface of a conductive substrate by electroplating, vapor deposition or chemical deposition to obtain a conductive substrate with an iron film. (2) A standard three-electrode electrochemical system was adopted, using a conductive substrate with an iron film as the working electrode. The working electrode was immersed in a mixed solution of K3[Fe(CN)6] and PEDOT:PSS, or a mixed solution of K3[Fe(CN)6] and MXene. Then, a constant voltage technique was used to release Fe from the working electrode. 2+ The composite electrode based on conductive hydrogel-Tunnel blue nanoparticles is prepared by ion gelation and generation of nanoparticles. In step (2), when using constant voltage technology, the voltage is 0.5 to 1V and is maintained for 20 to 100 seconds; In a mixed solution of K3[Fe(CN)6] and PEDOT:PSS, the concentration of K3[Fe(CN)6] is 1-10 mM and the mass concentration of PEDOT:PSS is 5-15 wt%. In a mixed solution of K3[Fe(CN)6] and MXene, the concentration of K3[Fe(CN)6] is 1–10 mM and the concentration of MXene is 5–10 mg / ml.

2. The method for preparing the composite electrode based on conductive hydrogel-Tunnel Blue nanoparticles according to claim 1, characterized in that, In step (1), the conductive substrate material includes gold or carbon.

3. The method for preparing the composite electrode based on conductive hydrogel-Tunnel Blue nanoparticles according to claim 1, characterized in that, In step (1), an iron film is modified on the surface of the conductive substrate by electroplating. The steps include: using a standard three-electrode electrochemical system, with an Ag / AgCl electrode as the reference electrode, a Pt electrode as the counter electrode, a conductive substrate as the working electrode, and a sulfuric acid solution containing FeCl2, sodium dodecyl sulfate and ascorbic acid as the electroplating solution, and using constant current technology to modify the iron film on the surface of the conductive substrate to obtain a conductive substrate with an iron film.

4. The method for preparing the composite electrode based on conductive hydrogel-Tunnel blue nanoparticles according to claim 3, characterized in that, When using constant current technology, the current density is -6 to -15 A / dm. 2 Hold for 10–50 seconds.

5. The method for preparing the composite electrode based on conductive hydrogel-Tunnel Blue nanoparticles according to claim 1, characterized in that, In step (2), a standard three-electrode electrochemical system is used, with an Ag / AgCl electrode as the reference electrode, a Pt electrode as the counter electrode, and a conductive substrate with an iron film as the working electrode.

6. The composite electrode based on conductive hydrogel-Tunnel blue nanoparticles prepared by the method for preparing the composite electrode based on conductive hydrogel-Tunnel blue nanoparticles according to any one of claims 1-5.

7. The application of the composite electrode based on conductive hydrogel-Tunnel blue nanoparticles as described in claim 6 in H2O2 detection.

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