Hydrogen peroxide sensor

Abstract

The invention belongs to the technical field of electrochemical monitoring, and particularly relates to a hydrogen peroxide sensor which comprises an insulating substrate and a counter electrode, a working electrode and a reference electrode which are printed on the insulating substrate at the same time, and graphene aerogel loaded with Prussian blue nanoparticles is adhered to the working end of the working electrode. According to the hydrogen peroxide sensor, the graphene aerogel loaded with the Prussian blue nanoparticles is adopted, the electron mobility is extremely high, the external environment change can be quickly responded, and the sensor has the characteristics of high conductivity and high sensitivity; the graphene aerogel loaded with the Prussian blue nanoparticles can also provide a large number of uniform loading sites for the Prussian blue nanoparticles, and the chemical property of the graphene aerogel is stable, so that the stability of the sensor is remarkably enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical monitoring, and particularly relates to a hydrogen peroxide sensor. Background Art

[0002] Loading Prussian blue (PB) nanoparticles can significantly improve the performance of hydrogen peroxide sensors. Prussian blue nanoparticles accelerate electron transfer with highly reversible redox properties, enhancing the response speed and sensitivity; they have a specific catalytic effect on the hydrogen peroxide reduction reaction, improving the monitoring efficiency; they catalyze the reaction at low potentials, reducing background interference and improving selectivity and accuracy; their porous structure provides a large number of active sites and can be evenly dispersed to expand the active surface area, further enhancing the monitoring ability and sensitivity. In short, loading Prussian blue nanoparticles optimizes the sensor performance in all aspects and makes it perform better in practical applications.

[0003] The hydrogen peroxide sensors loaded with Prussian blue nanoparticles are mainly divided into two categories. One category is the sensors containing metal particles, and such sensors usually have high sensitivity. When Prussian blue nanoparticles are loaded on a substrate made of metal materials such as gold (Au), platinum (Pt), palladium (Pd), nickel (Ni), copper (Cu), etc., the sensitivity of the sensor can be improved. For example, in the literature (Electroanalysis, (2013), 25: 2211 - 2220.), a novel Prussian blue nanoparticle / copper-gold bimetallic nanoparticle hybrid film modified electrode (PB / Cu-AuNPs / GCE) was prepared on a glassy carbon electrode by electrochemically depositing method. This sensor does not integrate the working electrode and the counter electrode, and the three-electrode system of an electrochemical instrument is used to evaluate the performance. Compared with the single Prussian blue nanoparticle modified electrode (PB / GCE), it shows better electrocatalytic activity in the hydrogen peroxide reduction reaction. However, such sensors have the problem of poor stability. Tracing back to the root cause, it mainly lies in the fact that there are many intractable problems with the metal nanoparticles as the key components. For example, metal nanoparticles such as silver and copper are easily oxidized in the air and corroded in the electrochemical environment, resulting in a decline in the sensor performance; due to their high surface energy, the agglomeration phenomenon is prominent, reducing the dispersibility and active surface area, and affecting the stability and sensitivity of the sensor; on the surface of carriers such as graphene, it is not only difficult for them to be evenly dispersed, but also the interfacial binding force is weak and they are easy to fall off; in terms of the preparation process, the modification requires complex methods such as chemical reduction and electrochemical deposition, and the conditions are strictly controlled; some metal nanoparticles have potential toxicity, may cause immune reactions, and have poor biocompatibility; in electrochemical monitoring, additional background signals will be generated, reducing the monitoring selectivity; during long-term use, the performance is prone to decay, the mechanical strength decreases, and the durability is poor; at the same time, they are sensitive to temperature, humidity and chemical environment; some high-performance metal nanoparticles also rely on rare metal resources, resulting in resource limitations. The other category is the sensors without metal particles and with a carbon material as the substrate, such as those loaded with Prussian blue nanoparticles with conductive polymers, carbon nanotubes, graphene, etc. as the substrate. The stability of such sensors has been improved. For example, in the literature (Electrochimica Acta 89 (2013): 454 - 460.), a reduced graphene oxide (RGO) suspension was dropped on the surface of a glassy carbon electrode (GC), and after drying, an electrode with RGO as the substrate was formed. Then, Prussian blue nanoparticles were deposited on the RGO electrode by electrochemically depositing method to form a GC / RGO / PB electrode. Similarly, because the working electrode and the counter electrode are not integrated, the three-electrode system of an electrochemical instrument is used to evaluate the performance. The highest sensitivity shown by this electrode is only 420 μA / (mM×cm²), and the sensitivity is relatively low. And currently, the carbon-based materials used to load Prussian blue nanoparticles are mostly two-dimensional structures, such as graphene films (RGO), carbon nanotubes (CNTs), ITO films, etc. Their specific surface areas are limited, resulting in limited loading amounts of Prussian blue nanoparticles.

[0004] Traditional metal-based hydrogen peroxide sensors have poor stability, while carbon-based ones have insufficient sensitivity. Therefore, the development of Prussian blue nanoparticle-loaded hydrogen peroxide sensors with both high sensitivity and high stability is of great significance to meet the needs of biomedicine, environmental monitoring and other fields. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problems existing in the prior art and to provide a hydrogen peroxide sensor.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] A hydrogen peroxide sensor comprises an insulating substrate and a counter electrode, a working electrode and a reference electrode which are printed on the insulating substrate at the same time, wherein a graphene aerogel loaded with Prussian blue nanoparticles is pasted on the working end of the working electrode.

[0008] The invention prepares a hydrogen peroxide sensor loaded with Prussian blue nanoparticles having the characteristics of high sensitivity, high stability and the like by pasting graphene aerogel loaded with Prussian blue nanoparticles on the working end of a working electrode through conductive silver glue or conductive silver paste.

[0009] On the one hand, graphene aerogel has a high electrical conductivity (5-15S / cm). As a loading substrate for Prussian blue nanoparticles, it can significantly improve the sensitivity of the sensor to changes in electronic current. The main reasons include: (1) Graphene aerogel has a three-dimensional continuous conductive network, which can greatly reduce the internal resistance of electron transmission and accelerate the transfer efficiency of reaction electrons. According to Ohm's law (V = IR), low resistance (R) can reduce voltage drop (V), thereby amplifying the signal-to-noise ratio of the current signal (I), making it easier to monitor small concentration changes; (2) The highly conductive substrate can suppress the double-layer capacitance effect and background noise, reduce the interface contact impedance, and enhance the distinction between Faraday current and background signals; (3) The synergistic effect of the three-dimensional continuous conductive network of graphene aerogel and Prussian blue nanoparticles can optimize the electronic structure of the catalytic active site, reduce the activation energy of the hydrogen peroxide reduction reaction, and accelerate the reaction kinetics, making the hydrogen peroxide sensor highly sensitive.

[0010] On the other hand, the three-dimensional continuous conductive network of graphene aerogel has a high specific surface area, which can provide a large number of uniform loading sites for Prussian blue nanoparticles, thus significantly improving the stability of the sensor. Specifically: the three-dimensional porous framework of graphene aerogel firmly anchors Prussian blue nanoparticles through physical confinement and chemical bonding (such as π-π interaction, hydrogen bond or covalent bond), preventing them from falling off or aggregating during electrochemical cycling or mechanical vibration, and reducing the loss of active sites; at the same time, the high specific surface area of graphene aerogel enables Prussian blue nanoparticles to be uniformly dispersed, avoiding "passivation" or "overload" of catalytic centers caused by excessive local concentration, and maintaining long-term catalytic efficiency. In addition, the three-dimensional continuous conductive network not only provides a low-resistance electron transport path, but its porous structure also promotes the penetration of electrolyte and ion diffusion, ensuring the continuous and efficient operation of the reaction interface, and reducing the performance decay caused by polarization or mass transfer limitation. The three-dimensional continuous conductive network structure of graphene aerogel can also buffer the direct impact of the external environment (such as temperature, humidity change or chemical corrosion), while the highly conductive substrate inhibits side reactions (such as oxidative decomposition) through rapid electron transfer, further extending the sensor life. This physical-chemical synergistic effect enables graphene aerogel to stably load Prussian blue nanoparticles, thus ensuring the reliable performance of the sensor during long-term use and in complex environments.

[0011] In the prior art, there are cases where aerogels are used in sensors. However, it mainly relies on the deformation of the aerogel itself to trigger changes in electrical signals to achieve the monitoring function, and is mainly used for monitoring motion signals. The monitoring principle is as follows: when the aerogel is subjected to external stimuli such as pressure, stretching or compression, it will deform, causing a change in its internal conductive network, and then resulting in changes in electrical signals such as resistance, capacitance or current. By measuring these changes in electrical signals, the intensity or type of external stimuli can be indirectly reflected.

[0012] Different from the prior art, the present invention utilizes the synergistic effect of the efficient three-dimensional continuous conductive network of graphene aerogel and the electrocatalytic properties of Prussian blue nanoparticles to achieve the monitoring function, for monitoring biochemical molecule (such as hydrogen peroxide) signals. The monitoring principle is: when the sensor comes into contact with a sample containing hydrogen peroxide (H2O2), Prussian blue nanoparticles catalyze its reduction reaction (H2O2 + 2H + + 2e -→ 2H2O), and the generated electrons are rapidly transferred to the electrode through the three-dimensional continuous conductive network of the aerogel, forming a current signal that is positively correlated with the H2O2 concentration. The high conductivity (5-15 S / cm) of the graphene aerogel can significantly reduce the electron transfer resistance. Its porous structure has a high specific surface area and can load more Prussian blue nanoparticles, and uses physical confinement and chemical bonding to enhance the stability of catalytic sites. At the same time, the high-selectivity catalysis of Prussian blue nanoparticles combined with the anti-interference characteristics of the graphene aerogel effectively inhibits the interference of other electroactive substances. Compared with traditional sensors that rely on physical deformation, the present invention realizes highly sensitive and highly specific monitoring of biochemical molecules through the synergistic effect of a highly conductive substrate and electrochemical activity, and expands the application potential of graphene aerogel in the fields of biomedicine and environmental monitoring.

[0013] As a preferred technical solution:

[0014] For a hydrogen peroxide sensor as described above, the thickness of the graphene aerogel is 500-1000 mm, the specific surface area is 1000-1200 m 2 / g, the porosity is 95-99%, the pore size is 5-20 mm, and the conductivity is 5-15 S / cm; the particle size of the Prussian blue nanoparticles is 40-100 nm; the loading area ratio of the Prussian blue nanoparticles on the surface of the graphene aerogel is 99-100%; the loading area ratio of the Prussian blue nanoparticles in the pores of the graphene aerogel is 99-100%.

[0015] For a hydrogen peroxide sensor as described above, the graphene aerogel loaded with Prussian blue nanoparticles completely covers the working end of the working electrode, and their shapes and sizes are the same.

[0016] For a hydrogen peroxide sensor as described above, the selection of the insulating substrate needs to consider factors such as its conductivity, corrosion resistance, and mechanical strength. Commonly used materials include glass, ceramics, plastics (such as PET, PVC, PI, etc.). The working electrode is printed with gold ink or carbon ink, the counter electrode is printed with gold ink or carbon ink, and the reference electrode is printed with silver / silver chloride ink.

[0017] For a hydrogen peroxide sensor as described above, an insulating layer is coated on the regions of the counter electrode, working electrode, and reference electrode except for the working end.

[0018] A hydrogen peroxide sensor as described above. The process of printing the counter electrode, working electrode, and reference electrode on the insulating substrate is as follows: Place the screen on the insulating substrate, and evenly squeeze the conductive ink corresponding to each electrode through the screen with a squeegee to ensure that it is accurately printed at the predetermined position, and then perform drying or curing. Among them, the design of the screen should be determined according to the requirements such as the shape, size, and conductivity of the electrode. Before placing the screen on the insulating substrate, the insulating substrate needs to be cleaned. Common methods include ultrasonic cleaning, deionized water washing, drying, etc., to ensure that there are no impurities such as oil stains and dust, so as to improve the printing quality.

[0019] A hydrogen peroxide sensor as described above. The process of pasting the graphene aerogel loaded with Prussian blue nanoparticles on the working end of the working electrode is as follows: After bonding the graphene aerogel loaded with Prussian blue nanoparticles to the working end of the working electrode with conductive silver paste, dry it at 80 - 100 °C for 10 - 20 min.

[0020] A hydrogen peroxide sensor as described above further includes an electrochemical device. The non - working ends of the counter electrode, working electrode, and reference electrode are simultaneously connected to the electrochemical device.

[0021] A hydrogen peroxide sensor as described above. The sensitivity of the hydrogen peroxide sensor is 500 - 600 μA / (mM×cm 2 ), the detection limit is 1 - 5 μM, the linear range is (1 - 5) - (800 - 1000) μM, and the response time is 0.5 - 2 s; after the hydrogen peroxide sensor continuously monitors 500 times, the monitoring current change rate is 1 - 5%; after the hydrogen peroxide sensor continuously monitors for 20 days, the monitoring current change rate is 2 - 7%; during the monitoring process of the hydrogen peroxide sensor, after adding a bioactive substance to the monitoring object, the monitoring current change rate is 1 - 3%, and the bioactive substance is one or more of ascorbic acid, glucose, dopamine, urea, and uric acid.

[0022] Beneficial effects:

[0023] (1) The graphene aerogel loaded with Prussian blue nanoparticles used in the hydrogen peroxide sensor of the present invention has an extremely high electron mobility, can quickly respond to changes in the external environment, and exhibits excellent sensitivity when monitoring trace substances, thus enabling the sensor to have the characteristics of high conductivity and high sensitivity.

[0024] (2) The three - dimensional continuous conductive network of the graphene aerogel loaded with Prussian blue nanoparticles used in the present invention has a high specific surface area, which can provide a large number of uniform loading sites for Prussian blue nanoparticles, thus significantly enhancing the stability of the sensor.

[0025] (3) The graphene aerogel loaded with Prussian blue nanoparticles used in the present invention has stable chemical properties and is not prone to reacting with other substances. Therefore, it can maintain the stable performance of the hydrogen peroxide sensor in harsh environments.

[0026] (4) Graphene has excellent mechanical strength and flexibility and can withstand large deformations without breaking, making the hydrogen peroxide sensor of the present invention suitable for flexible electronic devices and wearable sensors. Specific Embodiments

[0027] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by 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 appended claims of this application.

[0028] The test methods for the relevant indicators of the hydrogen peroxide sensor in the embodiments are as follows:

[0029] The test steps for sensitivity are as follows:

[0030] (1) Connect the three electrodes of the sensor to an electrochemical workstation (Autolab) and immerse it in a 0.1M HCl / KCl solution. Use the cyclic voltammetry program with the parameter settings: scanning voltage range -0.1~0.4V, scanning rate 0.01 - 0.08 V / s, and cycle 10 - 30 times to stabilize the Prussian blue nanoparticles;

[0031] (2) After rinsing the sensor three times with deionized water, transfer it to a monitoring solution of 1X PBS containing 0.1M KCl. Use the chronoamperometry program with the monitoring voltage set at -0.1~-0.5V; before adding hydrogen peroxide, activate the sensor for 60 - 100 min first; add hydrogen peroxide to the solution for the first time until the hydrogen peroxide concentration in the monitoring solution reaches 10 mM. After the current stabilizes, repeat the addition operation of adding an equimolar amount of hydrogen peroxide 3 - 5 times; obtain the current difference each time after adding hydrogen peroxide, and calculate the sensitivity each time through the formula " ", where in the formula, is the current difference, is the initial value of the hydrogen peroxide concentration in the monitoring solution each time after adding hydrogen peroxide, A is the electrode surface area.

[0032] The test steps for the detection limit are as follows:

[0033] (1) Connect the three electrodes of the sensor to an electrochemical workstation (Autolab), immerse it in a 0.1 M HCl / KCl solution, and use the cyclic voltammetry program with the following parameter settings: scanning voltage range -0.1 to 0.4 V, scanning rate 0.01 - 0.08 V / s, and cycle 10 - 30 times to stabilize the Prussian blue nanoparticles;

[0034] (2) After rinsing the sensor three times with deionized water, transfer it to a monitoring solution of 1X PBS containing 0.1 M KCl, and use the chronoamperometry program with the monitoring voltage set at -0.1 to -0.5 V; before adding hydrogen peroxide, activate the sensor for 60 - 100 min first; add hydrogen peroxide to the solution for the first time until the hydrogen peroxide concentration in the monitoring solution reaches 10 mM. After the current stabilizes, add an equimolar amount of hydrogen peroxide to the solution in the same steps until the hydrogen peroxide concentrations in the monitoring solution are 10 mM, 10 mM, 20 mM, 50 mM, 100 mM, 200 mM, 200 mM, 200 mM, and 200 mM respectively. Obtain the current difference each time the target hydrogen peroxide concentration is reached;

[0035] (3) Plot the standard curve of hydrogen peroxide concentration - current difference in the monitoring solution and calculate the slope S through linear fitting. The final limit of detection (LOD) is obtained from the formula "LOD = 3.3s / S"; s can be measured by two methods: one is to measure the blank value, that is, the standard deviation of the sensor current when the hydrogen peroxide concentration in the monitoring solution is zero, which is s, and the other is the residual standard deviation of the standard curve or the standard deviation of the intercept, which is s.

[0036] The test steps for the linear range are as follows:

[0037] (1) Connect the three electrodes of the sensor to an electrochemical workstation (Autolab), immerse it in a 0.1 M HCl / KCl solution, and use the cyclic voltammetry program with the following parameter settings: scanning voltage range -0.1 to 0.4 V, scanning rate 0.01 - 0.08 V / s, and cycle 10 - 30 times to stabilize the Prussian blue nanoparticles;

[0038] (2) After rinsing the sensor three times with deionized water, transfer it to a monitoring solution of 1X PBS containing 0.1 M KCl. Using a chronoamperometry procedure, set the monitoring voltage to -0.1 to -0.5 V; before adding hydrogen peroxide, activate the sensor for 60 - 100 min; first add hydrogen peroxide to the solution until the hydrogen peroxide concentration in the monitoring solution reaches 10 mM. After the current stabilizes, repeat adding an equimolar amount of hydrogen peroxide to the solution in the same steps until the monitoring current starts to rise; this indicates that the sensor has reached the upper limit of hydrogen peroxide monitoring. At this time, the total hydrogen peroxide concentration in the monitoring solution is the upper limit of the linear range, and the linear range is composed of the lower limit of monitoring to this upper limit concentration. The method for obtaining the lower limit of monitoring has been described in the previous text.

[0039] The test procedure for the response time is as follows:

[0040] (1) Connect the three electrodes of the sensor to an electrochemical workstation (Autolab), immerse it in a solution of 0.1 M HCl / KCl, and use a cyclic voltammetry procedure with the following parameter settings: scanning voltage range -0.1 to 0.4 V, scanning rate 0.01 - 0.08 V / s, and cycle 10 - 30 times to stabilize the Prussian blue nanoparticles;

[0041] (2) After rinsing the sensor three times with deionized water, transfer it to a monitoring solution of 1X PBS containing 0.1 M KCl. Using a chronoamperometry procedure, set the monitoring voltage to -0.1 to -0.5 V; before adding hydrogen peroxide, activate the sensor for 60 - 100 min; first add hydrogen peroxide to the solution until the hydrogen peroxide concentration in the monitoring solution reaches 100 mM. After the current stabilizes, calculate the time difference from the start of current change to stability. Repeat the operation of adding an equimolar amount of hydrogen peroxide until the hydrogen peroxide concentration in the monitoring solution reaches 100 mM and calculating the time difference, and take the average value of each time difference as the response time of the sensor.

[0042] The test procedure for the monitoring current change rate is as follows:

[0043] (1) Connect the three electrodes of the sensor to an electrochemical workstation (Autolab), immerse it in a solution of 0.1 M HCl / KCl, and use a cyclic voltammetry procedure with the following parameter settings: scanning voltage range -0.1 to 0.4 V, scanning rate 0.01 - 0.08 V / s, and cycle 10 - 30 times to stabilize the Prussian blue nanoparticles;

[0044] (2) After rinsing the sensor three times with deionized water, transfer it to a monitoring solution of 1X PBS containing 0.1M KCl. Using a chronoamperometry procedure, set the monitoring voltage to -0.1~-0.5V; before adding hydrogen peroxide, activate the sensor for 60 - 100 min; add hydrogen peroxide to the solution for the first time until the hydrogen peroxide concentration in the monitoring solution reaches 100 mM. After the current stabilizes, record the current difference at this time as the initial current difference of the sensor. Subsequently, continuously monitor the current difference 2 - 500 times or for 2 - 20 days (perform the operation once a day, and perform the same operation on the same sensor the next day) using the same steps. Calculate the stability monitoring current change rate according to the formula " "; in the formula, is n the current difference at the n time or day, and

[0045] is the initial current difference.

[0046] (1) Connect the three electrodes of the sensor to an electrochemical workstation (Autolab) and immerse it in a solution of 0.1M HCl / KCl. Using a cyclic voltammetry procedure, set the parameters as follows: scanning voltage range -0.1~0.4V, scanning rate 0.01 - 0.08 V / s, and cycle 10 - 30 times to stabilize the Prussian blue nanoparticles;

[0047] (2) After rinsing the sensor three times with deionized water, transfer it to a monitoring solution of 1X PBS containing 0.1M KCl. Using a chronoamperometry procedure, set the monitoring voltage to -0.1~-0.5V; before adding hydrogen peroxide, activate the sensor for 60 - 100 min; add hydrogen peroxide to the solution for the first time until the hydrogen peroxide concentration in the monitoring solution reaches 100 mM. After the current stabilizes, record the current value at this time as the initial current value of the hydrogen peroxide sensor. Subsequently, add a bioactive substance to the solution until the bioactive substance concentration in the monitoring solution reaches 100 mM. After the current stabilizes, record the current value at this time as the monitoring current value of the hydrogen peroxide sensor for the bioactive substance. Calculate the monitoring current change rate according to the formula " "; in the formula, is the monitoring current value of the bioactive substance, and is the initial current value.

[0048] The proportion of the loading area of Prussian blue nanoparticles on the surface of the graphene aerogel and the proportion of the loading area of Prussian blue nanoparticles in the pores of the graphene aerogel are calculated using Image J software from the scanning electron microscope images (SEM) of the surface and pores of the hydrogen peroxide sensor.

[0049] Example 1

[0050] A method for preparing a hydrogen peroxide sensor comprises the following specific steps:

[0051] (1) Printing a counter electrode, a working electrode and a reference electrode on an insulating substrate: placing a screen on the insulating substrate, and evenly extruding the conductive ink corresponding to each electrode through a squeegee across the screen. After ensuring that it is accurately printed at a predetermined position, drying or curing is carried out;

[0052] Among them, the working electrode uses gold ink (manufacturer: Huizhou Jinfuqi Industrial Co., Ltd., grade: LV53-121), the counter electrode uses gold ink (manufacturer: Huizhou Jinfuqi Industrial Co., Ltd., grade: LV53-121), and the reference electrode uses silver / silver chloride ink (manufacturer: Creative Materials Corporation, USA, model: 119-10);

[0053] (2) Pasting a graphene aerogel loaded with Prussian blue nanoparticles on the working end of the working electrode: bonding the graphene aerogel loaded with Prussian blue nanoparticles to the working end of the working electrode with conductive silver paste (the graphene aerogel loaded with Prussian blue nanoparticles completely covers the working end of the working electrode, and their shapes and sizes are the same), and drying at 80 °C for 20 min;

[0054] Among them, the average thickness of the graphene aerogel is 500 mm, the specific surface area is 1000 m 2 / g, the porosity is 95%, the average pore size is 5 mm, and the conductivity is 15 S / cm; the average particle size of the Prussian blue nanoparticles is 40 nm; the loading area ratio of the Prussian blue nanoparticles on the surface of the graphene aerogel is 100%; the loading area ratio of the Prussian blue nanoparticles in the pores of the graphene aerogel is 99%;

[0055] (3) Coating an insulating layer on the areas of the counter electrode, the working electrode and the reference electrode except for the working ends;

[0056] (4) Connecting the non-working ends of the counter electrode, the working electrode and the reference electrode to an electrochemical device simultaneously, thus obtaining the hydrogen peroxide sensor.

[0057] The sensitivity of the finally obtained hydrogen peroxide sensor is 580 μA / (mM×cm 2) The lower detection limit is 2 μM, the linear range is 2 - 1000 μM, and the response time is 0.5 s; after the hydrogen peroxide sensor continuously monitors 500 times, the monitoring current change rate is 1%; after the hydrogen peroxide sensor continuously monitors for 20 days, the monitoring current change rate is 2%; during the monitoring process of the hydrogen peroxide sensor, after adding a bioactive substance (any one of ascorbic acid, glucose, dopamine, urea, and uric acid) to the monitoring object, the monitoring current change rate is less than 3%.

[0058] Example 2

[0059] A preparation method of a hydrogen peroxide sensor, the specific steps are as follows:

[0060] (1) Printing the counter electrode, working electrode, and reference electrode on an insulating substrate: Place the screen on the insulating substrate, and evenly squeeze the conductive ink corresponding to each electrode through the screen with a squeegee. After ensuring that it is accurately printed at the predetermined position, dry or cure it;

[0061] Among them, the working electrode uses carbon ink (manufacturer: Shenzhen Tengyu High-Tech Materials Co., Ltd., brand: Field-808), the counter electrode uses carbon ink (manufacturer: Shenzhen Tengyu High-Tech Materials Co., Ltd., brand: Field-808), and the reference electrode uses silver / silver chloride ink (manufacturer: Creative Materials, USA, model: 119-10);

[0062] (2) Pasting the graphene aerogel loaded with Prussian blue nanoparticles on the working end of the working electrode: Bond the graphene aerogel loaded with Prussian blue nanoparticles on the working end of the working electrode with conductive silver paste (the graphene aerogel loaded with Prussian blue nanoparticles completely covers the working end of the working electrode, and their shapes and sizes are the same), and dry it at 100 °C for 10 min;

[0063] Among them, the average thickness of the graphene aerogel is 900 mm, the specific surface area is 1100 m 2 / g, the porosity is 98%, the average pore diameter is 18 mm, and the conductivity is 7 S / cm; the average particle size of the Prussian blue nanoparticles is 60 nm; the loading area ratio of the Prussian blue nanoparticles on the surface of the graphene aerogel is 99%; the loading area ratio of the Prussian blue nanoparticles in the pores of the graphene aerogel is 100%;

[0064] (3) Coating the insulating layer on the areas of the counter electrode, working electrode, and reference electrode except the working end;

[0065] (4) Simultaneously connecting the non-working ends of the counter electrode, working electrode, and reference electrode to an electrochemical device to obtain the hydrogen peroxide sensor.

[0066] The sensitivity of the finally obtained hydrogen peroxide sensor is 500 μA / (mM×cm 2 ), the lower detection limit is 4 μM, the linear range is 4 - 1000 μM, and the response time is 1.5 s; after the hydrogen peroxide sensor continuously monitors 500 times, the change rate of the monitored current is 1%; after the hydrogen peroxide sensor continuously monitors for 20 days, the change rate of the monitored current is 3%; during the monitoring process of the hydrogen peroxide sensor, after adding a bioactive substance (any one of ascorbic acid, glucose, and dopamine) to the monitored object, the change rate of the monitored current is less than 1%.

[0067] Example 3

[0068] A preparation method of a hydrogen peroxide sensor, the specific steps are as follows:

[0069] (1) Printing the counter electrode, working electrode, and reference electrode on an insulating substrate: Place the screen on the insulating substrate, and evenly squeeze the conductive ink corresponding to each electrode through the screen with a squeegee. After ensuring that it is accurately printed at the predetermined position, dry or cure it;

[0070] Among them, the working electrode uses carbon ink (manufacturer: Shenzhen Tengyu High-Tech Materials Co., Ltd., brand: Field-808), the counter electrode uses carbon ink (manufacturer: Shenzhen Tengyu High-Tech Materials Co., Ltd., brand: Field-808), and the reference electrode uses silver / silver chloride ink (manufacturer: Creative Materials Company, USA, model: 119-10);

[0071] (2) Pasting the graphene aerogel loaded with Prussian blue nanoparticles on the working end of the working electrode: Bond the graphene aerogel loaded with Prussian blue nanoparticles to the working end of the working electrode with conductive silver paste (the graphene aerogel loaded with Prussian blue nanoparticles completely covers the working end of the working electrode, and their shapes and sizes are the same), and dry it at 90 °C for 20 min;

[0072] Among them, the average thickness of the graphene aerogel is 1000 mm, the specific surface area is 1200 m 2 / g, the porosity is 99%, the average pore size is 20 mm, and the conductivity is 5 S / cm; the average particle size of the Prussian blue nanoparticles is 100 nm; the loading area ratio of the Prussian blue nanoparticles on the surface of the graphene aerogel is 100%; the loading area ratio of the Prussian blue nanoparticles in the pores of the graphene aerogel is 100%;

[0073] (3) Coating the insulating layer on the areas of the counter electrode, working electrode, and reference electrode except for the working end;

[0074] (4)Connect the non-working ends of the counter electrode, working electrode, and reference electrode to the electrochemical device simultaneously, and a hydrogen peroxide sensor is obtained.

[0075] The sensitivity of the finally prepared hydrogen peroxide sensor is 530 μA / (mM×cm 2 ), the lower detection limit is 1 μM, the linear range is 1 - 900 μM, and the response time is 2 s; after the hydrogen peroxide sensor continuously monitors 500 times, the change rate of the monitoring current is 5%; after the hydrogen peroxide sensor continuously monitors for 20 days, the change rate of the monitoring current is 7%; during the monitoring process of the hydrogen peroxide sensor, when a bioactive substance (any one of ascorbic acid, glucose, urea, and uric acid) is added to the monitoring object, the change rate of the monitoring current is less than 2%.

[0076] Example 4

[0077] A preparation method of a hydrogen peroxide sensor, the specific steps are as follows:

[0078] (1)Print the counter electrode, working electrode, and reference electrode on the insulating substrate: Place the screen on the insulating substrate, and evenly squeeze the conductive ink corresponding to each electrode through the screen with a squeegee. After ensuring that it is accurately printed at the predetermined position, dry or cure it;

[0079] Among them, the working electrode uses gold ink (manufacturer: Huizhou Jinfuqi Industrial Co., Ltd., brand: LV53 - 121), the counter electrode uses gold ink (manufacturer: Huizhou Jinfuqi Industrial Co., Ltd., brand: LV53 - 121), and the reference electrode uses silver / silver chloride ink (manufacturer: Creative Materials, USA, model: 119 - 10);

[0080] (2)Paste the graphene aerogel loaded with Prussian blue nanoparticles on the working end of the working electrode: Bond the graphene aerogel loaded with Prussian blue nanoparticles to the working end of the working electrode with conductive silver paste (the graphene aerogel loaded with Prussian blue nanoparticles completely covers the working end of the working electrode, and their shapes and sizes are the same), and dry it at 95 °C for 15 min;

[0081] Among them, the average thickness of the graphene aerogel is 700 mm, the specific surface area is 1050 m 2 / g, the porosity is 96%, the average pore diameter is 10 mm, and the conductivity is 11 S / cm; the average particle size of the Prussian blue nanoparticles is 80 nm; the load area ratio of the Prussian blue nanoparticles on the surface of the graphene aerogel is 100%; the load area ratio of the Prussian blue nanoparticles in the pores of the graphene aerogel is 100%;

[0082] (3) Coat the areas of the counter electrode, working electrode, and reference electrode except for the working ends with an insulating layer;

[0083] (4) Simultaneously connect the non-working ends of the counter electrode, working electrode, and reference electrode to an electrochemical device, thus obtaining a hydrogen peroxide sensor.

[0084] The sensitivity of the finally obtained hydrogen peroxide sensor is 600 μA / (mM×cm 2 ), the lower detection limit is 5 μM, the linear range is 5 - 1000 μM, and the response time is 1 s; after the hydrogen peroxide sensor continuously conducts 500 monitoring operations, the change rate of the monitoring current is 1%; after the hydrogen peroxide sensor continuously conducts 20-day monitoring, the change rate of the monitoring current is 2%; during the monitoring process of the hydrogen peroxide sensor, after adding a bioactive substance (any one of dopamine, urea, and uric acid) to the monitoring object, the change rate of the monitoring current is less than 1%.

[0085] Example 5

[0086] A preparation method of a hydrogen peroxide sensor, the specific steps are as follows:

[0087] (1) Print the counter electrode, working electrode, and reference electrode on an insulating substrate: Place the screen on the insulating substrate, and evenly squeeze the conductive ink corresponding to each electrode through the screen with a squeegee. After ensuring that it is accurately printed at the predetermined position, perform drying or curing;

[0088] Among them, the working electrode uses gold ink (manufacturer: Huizhou Jinfuqi Industry Co., Ltd., brand: LV53 - 121), the counter electrode uses gold ink (manufacturer: Huizhou Jinfuqi Industry Co., Ltd., brand: LV53 - 121), and the reference electrode uses silver / silver chloride ink (manufacturer: Creative Materials Corporation, USA, model: 119 - 10);

[0089] (2) Paste the graphene aerogel loaded with Prussian blue nanoparticles on the working end of the working electrode: Bond the graphene aerogel loaded with Prussian blue nanoparticles to the working end of the working electrode with conductive silver paste (the graphene aerogel loaded with Prussian blue nanoparticles completely covers the working end of the working electrode, and their shapes and sizes are the same), and dry it at 90 °C for 10 min;

[0090] Among them, the average thickness of the graphene aerogel is 800 mm, the specific surface area is 1090 m 2 / g, the porosity is 97%, the average pore diameter is 15 mm, and the conductivity is 9 S / cm; the average particle size of the Prussian blue nanoparticles is 70 nm; the loading area ratio of the Prussian blue nanoparticles on the surface of the graphene aerogel is 100%; the loading area ratio of the Prussian blue nanoparticles in the pores of the graphene aerogel is 99%;

[0091] (3) Coating an insulating layer on the regions of the counter electrode, working electrode and reference electrode except for the working ends;

[0092] (4) Connecting the non-working ends of the counter electrode, working electrode and reference electrode to an electrochemical device simultaneously, thus obtaining a hydrogen peroxide sensor.

[0093] The sensitivity of the finally obtained hydrogen peroxide sensor is 560 μA / (mM×cm 2 ), the lower limit of detection is 1 μM, the linear range is 1 - 1000 μM, and the response time is 0.8 s; after the hydrogen peroxide sensor is continuously monitored 500 times, the change rate of the monitored current is 2%; after the hydrogen peroxide sensor is continuously monitored for 20 days, the change rate of the monitored current is 5%; during the monitoring process of the hydrogen peroxide sensor, after adding a bioactive substance (any one of ascorbic acid, dopamine, urea and uric acid) to the monitored object, the change rate of the monitored current is less than 2%.

[0094] Example 6

[0095] A preparation method of a hydrogen peroxide sensor, the specific steps are as follows:

[0096] (1) Printing a counter electrode, a working electrode and a reference electrode on an insulating substrate: placing a screen on the insulating substrate, and evenly squeezing the conductive ink corresponding to each electrode through the screen by a squeegee, and after ensuring that it is accurately printed at a predetermined position, drying or curing;

[0097] Among them, the working electrode uses carbon ink (manufacturer: Shenzhen Tengyu High-Tech Materials Co., Ltd., brand: Field-808), the counter electrode uses carbon ink (manufacturer: Shenzhen Tengyu High-Tech Materials Co., Ltd., brand: Field-808), and the reference electrode uses silver / silver chloride ink (manufacturer: Creative Materials Company, USA, model: 119-10);

[0098] (2) Pasting a graphene aerogel loaded with Prussian blue nanoparticles on the working end of the working electrode: bonding the graphene aerogel loaded with Prussian blue nanoparticles to the working end of the working electrode with conductive silver paste (the graphene aerogel loaded with Prussian blue nanoparticles completely covers the working end of the working electrode, and their shapes and sizes are the same), and drying at 85 °C for 20 min;

[0099] Among them, the average thickness of the graphene aerogel is 600 mm, and the specific surface area is 1030 m 2 / g, with a porosity of 96%, an average pore size of 8 mm, and a conductivity of 14 S / cm; the average particle size of the Prussian blue nanoparticles is 50 nm; the loading area ratio of the Prussian blue nanoparticles on the surface of the graphene aerogel is 100%; the loading area ratio of the Prussian blue nanoparticles in the pores of the graphene aerogel is 100%;

[0100] (3)Coat the areas of the counter electrode, working electrode, and reference electrode other than the working ends with an insulating layer;

[0101] (4)Simultaneously connect the non-working ends of the counter electrode, working electrode, and reference electrode to an electrochemical device to obtain a hydrogen peroxide sensor.

[0102] The sensitivity of the finally prepared hydrogen peroxide sensor is 540 μA / (mM×cm 2 ), the lower limit of detection is 1 μM, the linear range is 1 - 800 μM, and the response time is 0.7 s; after the hydrogen peroxide sensor continuously performs 500 monitoring times, the monitoring current change rate is 3%; after the hydrogen peroxide sensor continuously performs 20-day monitoring, the monitoring current change rate is 6%; during the monitoring process of the hydrogen peroxide sensor, after adding a bioactive substance (any one of glucose, dopamine, and urea) to the monitoring object, the monitoring current change rate is less than 1%.

Claims

1. A hydrogen peroxide sensor, comprising an insulating substrate and a counter electrode, a working electrode and a reference electrode printed on the insulating substrate simultaneously, characterized in that, A graphene aerogel loaded with Prussian blue nanoparticles is pasted on the working end of the working electrode.

2. The hydrogen peroxide sensor according to claim 1, characterized in that, The thickness of the graphene aerogel is 500 - 1000 mm, the specific surface area is 1000 - 1200 m 2 / g, the porosity is 95 - 99%, the pore size is 5 - 20 mm, and the conductivity is 5 - 15 S / cm; the particle size of the Prussian blue nanoparticles is 40 - 100 nm; the proportion of the loading area of the Prussian blue nanoparticles on the surface of the graphene aerogel is 99 - 100%; the proportion of the loading area of the Prussian blue nanoparticles in the pores of the graphene aerogel is 99 - 100%.

3. The hydrogen peroxide sensor according to claim 1, characterized in that, The graphene aerogel loaded with Prussian blue nanoparticles completely covers the working end of the working electrode, and they have the same shape and size.

4. The hydrogen peroxide sensor according to claim 1, characterized in that, The working electrode is printed with gold ink or carbon ink, the counter electrode is printed with gold ink or carbon ink, and the reference electrode is printed with silver / silver chloride ink.

5. A hydrogen peroxide sensor according to claim 4, characterized in that, An insulating layer is coated on the regions of the counter electrode, working electrode, and reference electrode except for the working ends.

6. The hydrogen peroxide sensor according to claim 4, wherein The process of printing the counter electrode, working electrode, and reference electrode on the insulating substrate is as follows: Place the screen on the insulating substrate, and evenly squeeze the conductive ink corresponding to each electrode through the screen with a squeegee. After ensuring that it is accurately printed at the predetermined position, dry or cure it.

7. A hydrogen peroxide sensor according to claim 1, wherein The process of pasting the graphene aerogel loaded with Prussian blue nanoparticles on the working end of the working electrode is as follows: Bond the graphene aerogel loaded with Prussian blue nanoparticles to the working end of the working electrode with conductive silver paste, and then dry it at 80 - 100 °C for 10 - 20 min.

8. The hydrogen peroxide sensor according to claim 1, characterized in that, It also includes an electrochemical device, and the non-working ends of the counter electrode, working electrode, and reference electrode are simultaneously connected to the electrochemical device.

9. The hydrogen peroxide sensor according to claim 1, characterized in that, The sensitivity of the hydrogen peroxide sensor is 500 - 600 μA / (mM×cm 2 ), the lower limit of detection is 1 - 5 μM, the linear range is (1 - 5) - (800 - 1000) μM, and the response time is 0.5 - 2 s; after the hydrogen peroxide sensor continuously monitors 500 times, the change rate of the monitoring current is 1 - 5%; after the hydrogen peroxide sensor continuously monitors for 20 days, the change rate of the monitoring current is 2 - 7%; during the monitoring of the hydrogen peroxide sensor, after adding a bioactive substance to the monitoring object, the change rate of the monitoring current is 1 - 3%, and the bioactive substance is one or more of ascorbic acid, glucose, dopamine, urea, and uric acid.