Method and device for preparing hydrogen peroxide through hydrazine hydrate oxidation assisted self-power supply

Abstract

The invention belongs to the technical field of electrochemical preparation of hydrogen peroxide, and particularly discloses a method and a device for preparing hydrogen peroxide through hydrazine hydrate oxidation assisted self-power supply. The device comprises an electrochemical reactor, a circulating feeding device and a gas conveying device, the electrochemical reactor comprises a gas diffusion chamber, a cathode, a cathode chamber, a proton exchange membrane, an anode chamber and an anode which are arranged in sequence, and the cathode is a gas diffusion electrode attached with a NiSe2 catalyst layer; the anode is a foam nickel electrode of electro-deposited Ru / Co (OH) 2; the cathode and the anode are connected through a lead; the circulating feeding device comprises a cathode circulating buffer tank, an anode circulating buffer tank and conveying equipment; the gas conveying device comprises an oxygen steel cylinder used for conveying oxygen. According to the invention, hydrogen peroxide electrochemical synthesis and hydrazine hydrate oxidation reaction are coupled, the system can be converted from traditional external power supply to a self-powered system, power input is not needed, and hydrogen peroxide production with maximum efficiency is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochemical preparation of hydrogen peroxide, and particularly relates to a method and a device for preparing hydrogen peroxide by hydrazine hydrate oxidation-assisted self-power supply. Background Art

[0002] Hydrogen peroxide (H 2 O 2 ) is an important chemical that is widely used in various industries, such as chemical synthesis, energy, medical disinfection, sewage treatment, bleaching, and aircraft fuel. It synthesizes H 2 O 2 It is an emerging synthetic route that only requires oxygen as a reactant, water or acid as a proton source, and renewable electricity as a power source to achieve environmental, pollution-free and energy-saving H 2 O 2 The synthesis is environmentally friendly and has on-site production capabilities, avoiding the high energy input and organic waste output, complex process and other problems of industrial production of hydrogen peroxide using traditional anthraquinone technology.

[0003] Hydrogen peroxide will decompose under alkaline conditions with a pH higher than 11.6. 2 O 2 The chelating agent used will bring additional cost; in contrast, the weakly acidic H 2 O 2 It has a longer shelf life in acidic electrolytes. 2 O 2 As an oxidant, it can pass through Fe in acidic solution. 2+ The mediated electro-Fenton process is further converted into more oxidative hydroxyl radicals, which can be applied to remove pollutants in the environment and upgrade biomass to obtain high value-added products. Therefore, electrochemical preparation of hydrogen peroxide under acidic conditions can avoid rapid decomposition under alkaline conditions, and can be used for wastewater treatment, organic degradation and chemical upgrading, with more significant application prospects. Summary of the invention

[0004] The purpose of the present invention is to provide a method and device for preparing hydrogen peroxide by hydrazine hydrate oxidation-assisted self-power supply. The present invention couples the electrochemical synthesis of hydrogen peroxide with the hydrazine hydrate oxidation reaction, and can transform the system from a traditional external power supply to a self-power supply system, without the need for power input, to achieve the most efficient hydrogen peroxide production.

[0005] The technical solution adopted to achieve the purpose of the present invention is:

[0006] The first aspect of the present invention provides a device for preparing hydrogen peroxide by hydrazine hydrate oxidation-assisted self-powered electricity, comprising an electrochemical reactor, a circulating feeding device and a gas conveying device, wherein the electrochemical reactor comprises a gas diffusion chamber, a cathode, a cathode chamber, a proton exchange membrane, an anode chamber and an anode arranged in sequence, wherein the cathode is a NiSe-attached 2 The gas diffusion electrode of the catalytic layer is used to efficiently reduce oxygen to hydrogen peroxide. It is located between the cathode chamber and the gas diffusion chamber. The cathode electrolyte in the cathode chamber can directly contact the cathode; the anode is the electrodeposited Ru / Co(OH) 2 The nickel foam electrode, the Ru / Co(OH) 2 It has a nanosheet structure, and Ru is evenly distributed in the form of single atoms in Co(OH) 2 The surface is used for efficiently oxidizing hydrazine hydrate, and is arranged between the anode chamber and the clamping plate, and the anode electrolyte in the anode chamber can directly contact the anode; the cathode and the anode are connected by a wire;

[0007] The circulating feeding device comprises a cathode circulating buffer tank, an anode circulating buffer tank and a conveying device;

[0008] The gas delivery device includes an oxygen cylinder for delivering oxygen. The oxygen passes through the gas diffusion layer of the gas diffusion electrode in the gas diffusion chamber to reach the catalytic layer on the cathode chamber side to react. The oxygen that does not pass through the gas diffusion layer flows back to the cathode circulation buffer tank through a pipeline.

[0009] The cathode chamber is connected to the cathode circulation buffer tank through a conveying pipeline, and the cathode electrolyte is circulated between the cathode chamber and the cathode circulation buffer tank; the anode chamber is connected to the anode circulation buffer tank through a conveying pipeline, and the anode electrolyte is circulated between the anode chamber and the anode circulation buffer tank; the conveying equipment is arranged on the conveying pipeline.

[0010] The present invention couples the electrochemical synthesis of hydrogen peroxide with the oxidation reaction of hydrazine hydrate, and can transform the system into a self-powered system. The positive and negative electrodes can react only by connecting wires, and the reactor can produce hydrogen peroxide without connecting to power facilities. 2 The gas diffusion electrode of the catalyst can not only effectively transmit oxygen, but also efficiently reduce oxygen to hydrogen peroxide at the cathode, which is accumulated in the cathode circulation buffer tank. The anode adopts electrodeposition of Ru / Co(OH) 2 The nickel foam integral electrode can efficiently oxidize hydrazine hydrate.

[0011] According to the above scheme, the gas diffusion layer of the cathode faces the gas diffusion chamber 1, and the catalytic layer faces the cathode chamber 3.

[0012] According to the above scheme, titanium foil is placed on the cathode 2 and the anode 6 so that it is in contact with the electrode sheet and partially exposed outside the reactor so that the positive and negative electrodes can be coupled through wires later.

[0013] According to the above scheme, the NiSe 2 It has a regular octahedral configuration. Preparation method: It is obtained by hydrothermal reaction of nickel chloride and selenium powder in a mixed solution of hydrazine hydrate / water, the hydrothermal reaction temperature is 120-160℃, and the reaction time is 18-22h.

[0014] According to the above scheme, one side of the gas diffusion electrode catalyst is coated with NiSe 2 Configured NiSe 2 Dispersion Formation NiSe 2 Catalytic layer, NiSe 2 The dispersion is made of NiSe 2 , deionized water, anhydrous ethanol, and Nafion stock solution.

[0015] According to the above scheme, the Ru / Co(OH) 2 The preparation method of nickel foam electrode is as follows: nickel foam is used as the working electrode, a solution of cobalt nitrate and ruthenium trichloride is used as the electrolyte, a platinum electrode is used as the counter electrode, and a saturated calomel reference electrode is used to construct a three-electrode system, and a current-time curve is set. At a potential of -0.8V--1.2V, the reaction time is set to 300-900s, and the electrodeposited Ru / Co(OH) can be obtained after cleaning and drying. 2 of nickel foam electrode.

[0016] According to the above scheme, the concentration of the cobalt nitrate solution is 0.03-0.05 mol / L, and the concentration of the ruthenium trichloride solution is 1-3 mg / mL.

[0017] According to the above scheme, the cathode electrolyte is a sulfuric acid electrolyte, and the anode electrolyte is a mixed solution of potassium hydroxide and hydrazine hydrate.

[0018] Specifically, the concentration of the sulfuric acid electrolyte can be selected to be 0.01-0.1M, the concentration of hydrazine hydrate can be selected to be 0.1-1M, and the concentration of potassium hydroxide can be selected to be 0.5-2M.

[0019] According to the above scheme, a gas flow controller is arranged on the gas delivery pipeline connecting the oxygen cylinder and the gas diffusion chamber. The oxygen flow rate is controlled by the gas flow controller between the oxygen cylinder and the gas diffusion chamber.

[0020] In one embodiment of the present invention, the cathode electrolyte is a 0.05M sulfuric acid solution, and the anode electrolyte is a mixed solution of 1M potassium hydroxide and 0.5M hydrazine hydrate.

[0021] In one embodiment of the present invention, the delivery device is a peristaltic pump.

[0022] The second aspect of the present invention provides a method for preparing hydrogen peroxide by self-powered hydrazine hydrate oxidation assistance, which is implemented based on the device for preparing hydrogen peroxide by self-powered hydrazine hydrate oxidation assistance according to the first aspect of the present invention, and is used for self-powered continuous preparation of hydrogen peroxide, comprising the following steps:

[0023] The anode electrolyte is pumped into the anode chamber from the anode circulation buffer tank, flows through the anode from the bottom of the anode, and is finally discharged from the upper end of the anode chamber to the anode circulation buffer tank; the cathode electrolyte is pumped into the cathode chamber from the cathode ring buffer tank, flows through the cathode from the bottom of the cathode, and is finally discharged from the upper end of the cathode chamber to the cathode circulation buffer tank; oxygen flows in from the gas diffusion chamber, part of the gas flows through the cathode to the cathode side catalyst layer, and the remaining gas flows into the cathode circulation buffer tank. In this process, the cathode and the anode are connected by a wire, hydrazine hydrate is oxidized to nitrogen on the anode side, and the oxygen flowing into the gas diffusion chamber is reduced to hydrogen peroxide on the cathode surface, and the hydrogen peroxide is accumulated in the cathode circulation buffer tank.

[0024] The following reaction occurs at the cathode:

[0025] O 2 +2H + +2e - →H 2 O 2

[0026] The following reaction occurs at the anode:

[0027] N 2 H 4 +4OH - →N 2 +4H 2 O+4e -

[0028] According to the above scheme, high-purity oxygen is used, and the flow rate is controlled to be 20-50 mL / min, for example, the flow rate used is 20 mL / min, 30 mL / min, 40 mL / min, and 50 mL / min. By adjusting the oxygen flow rate, the circulation speed of oxygen in the solution can be affected.

[0029] According to the above scheme, the flow rate of the electrolyte is preferably in the range of 50-200 mL / min, for example, the flow rate used is 50 mL / min, 100 mL / min, 150 mL / min, 200 mL / min. The flow rate of the electrolyte in the electrochemical reactor can be adjusted by adjusting the flow rate of the electrolyte.

[0030] The beneficial effects of the present invention are:

[0031] The method for electrochemically generating hydrogen peroxide provided by the present invention couples the electrochemical synthesis of hydrogen peroxide and the hydrazine hydrate oxidation reaction, utilizes the low starting potential of the hydrazine hydrate oxidation in the system of the present invention to couple it with the oxygen reduction reaction, and uses the hydrazine hydrate oxidation to assist the cathode oxygen reduction reaction, so that the system can be transformed from a traditional external power supply to a self-powered system, so that the entire system can efficiently produce chemical hydrogen peroxide under acidic conditions without external power supply, the system has good stability, and a new type of hydrogen peroxide electrosynthesis method is successfully constructed. The entire system saves energy, has high economic value, has certain stability, has industrial application potential, is environmentally friendly, and is conducive to achieving dual carbon goals.

[0032] The present invention provides a device for preparing hydrogen peroxide by self-powered hydrazine hydrate oxidation assistance, wherein a reactor cooperates with a circulating feeding device and a gas conveying device to realize efficient and stable production of cathode hydrogen peroxide under acidic conditions. In the present invention, the cathode and cathode electrolytes and the required oxygen can automatically and quantitatively enter the reactor and circulate in the system, so that the system can operate stably.

[0033] The hydrogen peroxide prepared by the invention can be applied to the fields of chemical synthesis, energy, medical disinfection, sewage treatment, etc., and has market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementations can be obtained based on these drawings without creative work.

[0035] Figure 1 This is a schematic diagram of a system for self-powered preparation of hydrogen peroxide by hydrazine hydrate oxidation assistance, in which: 1 gas diffusion chamber, 2 cathode, 3 cathode chamber, 4 proton exchange membrane, 5 anode chamber, 6 anode, 7 cathode circulation buffer tank, 8 anode circulation buffer tank, 9 oxygen cylinder, 10 gas flow controller, 11 clamp.

[0036] Figure 2 This is a schematic diagram of the assembly of a device for preparing hydrogen peroxide by hydrazine hydrate oxidation assisted self-power supply according to an embodiment of the present invention.

[0037] Figure 3 This is a physical picture of the device for preparing hydrogen peroxide by hydrazine hydrate oxidation-assisted self-power supply.

[0038] Figure 4 For coating NiSe 2 Actual picture of gas diffusion electrode in dispersion liquid.

[0039] Figure 5 NiSe2 XRD and SEM images of NiSe 2 XRD of b is NiSe 2 SEM image of .

[0040] Figure 6 For electrodeposition of Ru / Co(OH) 2 Physical picture of the nickel foam electrode.

[0041] Figure 7 For electrodeposition of Ru / Co(OH) 2 XRD pattern of the electrode.

[0042] Figure 8 For electrodeposition of Ru / Co(OH) 2 SEM image of nickel foam electrode.

[0043] Fig. 9 For electrodeposition of Ru / Co(OH) 2 HAADF-STEM image of nickel foam electrode.

[0044] Fig.10 For electrodeposition of Ru / Co(OH) 2 Polarization curve of electrochemical oxidation of hydrazine hydrate on nickel foam electrode.

[0045] Fig.11 For coating NiSe 2 Activity diagram of the gas diffusion electrode with catalytic layer for electrochemical reduction of oxygen to produce hydrogen peroxide.

[0046] Fig.12 Open circuit potential diagram of the device for self-powered preparation of hydrogen peroxide by hydrazine hydrate oxidation.

[0047] Fig.13 This is the discharge curve of the device for preparing hydrogen peroxide by self-powered hydrazine hydrate oxidation.

[0048] Fig.14 A graph of the concentration change of hydrogen peroxide generated over time by a device for preparing hydrogen peroxide by self-powering hydrazine hydrate oxidation. DETAILED DESCRIPTION

[0049] In order to better explain the present invention, the main contents of the present invention are further explained below in conjunction with specific embodiments, but the contents of the present invention are not limited to the following embodiments.

[0050] The anode 6 electrode used in the embodiment of the present invention is an electrodeposited Ru / Co(OH) 2 The nickel foam electrode has a cutting area of ​​2*3cm 2 , where electrodeposition of Ru / Co(OH) 2 The area is 2*2cm2 ; Nickel foam thickness: 1mm.

[0051] The cathode 2 electrode used in the embodiment of the present invention is coated with NiSe 2 Gas diffusion electrode for dispersion, with a cutting area of ​​3*3.5cm 2 ,NiSe 2 The dispersion is applied on the catalyst layer, with a coating area of ​​2*2cm 2 .

[0052] Example 1: Preparation of anode 6 electrode

[0053] Step 1: Pretreatment of nickel foam:

[0054] Cut the nickel foam into 2*3cm 2 , put it into a centrifuge tube, and use acetone, anhydrous ethanol and deionized water for ultrasonic treatment for 15 minutes respectively, and then place it in an oven to dry for later use.

[0055] Step 2: Preparation of deposition solution:

[0056] Prepare 0.05 mol / L cobalt nitrate solution and 2 mg / mL ruthenium chloride solution respectively. Add 15 mL cobalt nitrate solution (0.05 mol / L), 6 mL ruthenium chloride solution (2 mg / mL) and 9 mL deionized water into a 50 mL beaker, mix well by ultrasonication and set aside.

[0057] Step 3: Electrochemical in-situ deposition:

[0058] The nickel foam treated in step 1 is clamped on the electrode clamp as the working electrode, and it is immersed in the deposition liquid through the deposition rack. The platinum mesh electrode is placed at the rear end of the working electrode, and the saturated calomel reference electrode is placed at the front end of the working electrode, keeping the three in a straight line. Using the electrochemical workstation, after each electrode clamp is clamped, set the current-time curve. At a potential of -1.0V, the reaction time is 900s. After the reaction is completed, the nickel foam of the working electrode is taken out, and it is washed with anhydrous ethanol and deionized water respectively. After drying, the electrodeposited Ru / Co(OH) can be obtained. 2 of nickel foam electrode.

[0059] Anode prepared in Example (electrodeposition of Ru / Co(OH) 2 The actual picture of nickel foam electrode is as follows Figure 6 As shown in the SEM images Figure 8 As shown in the figure, the electrodeposited Ru / Co(OH) 2 @C XRD characterization see Figure 7 , the ruthenium chloride solution was replaced with water to obtain the electrodeposited Co(OH) 2@C for comparison. Figure 7 It can be seen that Co(OH) 2 Characteristic diffraction peaks, no crystalline Ru, indicating that electrodeposition produced Co(OH) 2 ,Ru / Co(OH) 2 @C and Co(OH) 2 @C has no change in its XRD characteristic peaks. Figure 8 It can be seen that the Ru / Co(OH) electrodeposited on the nickel foam electrode 2 It has a nano-sheet structure.

[0060] The spherical aberration electron microscope image of anode 6 is as follows Fig. 9 As shown, it can be seen that Ru is evenly distributed in the form of single atoms in Co(OH) 2 surface.

[0061] The oxidation performance of hydrazine hydrate at anode 6 is as follows Fig.10 As shown, Ru / Co(OH) 2 It has an extremely low starting potential of -0.1 V; compared with the oxygen evolution reaction, it can reach 100 mA cm -2 The potential is advanced by 1.637V at the current density of . The anode of the traditional electrochemical hydrogen peroxide synthesis system uses a simple platinum mesh electrode. The oxygen evolution reaction occurring on this electrode has slow kinetics and extremely high anode potential, so that a higher potential must be applied externally to drive the reaction, which greatly increases the energy consumption of the coupling system. The hydrazine hydrate oxidation reaction (HzOR) has a great kinetic advantage over the oxygen evolution reaction (OER). Replacing OER with HzOR can lead to a significant reduction in the anode potential.

[0062] Example 2: Preparation of cathode 2 electrode

[0063] Step 1: Hydrothermal synthesis of NiSe 2 :

[0064] Weigh 0.4758g nickel chloride and 0.6312g selenium powder and add them to 40mL of a mixed solution of hydrazine hydrate / water with a volume ratio of 3:1, and ultrasonicate for 10min to make it evenly dispersed. Then transfer it to a 50mL stainless steel reactor lined with polytetrafluoroethylene, react at 140℃ for 20h, open the reactor after cooling naturally to room temperature, centrifuge and wash with deionized water and anhydrous ethanol for several times, and then place it in a vacuum drying oven to dry for 6h to obtain the product NiSe 2 .

[0065] Step 2: NiSe 2 Dispersion liquid configuration:

[0066] Weigh 3 mg NiSe 2The powder was placed in a small glass bottle, and 120 μL of deionized water, 360 μL of anhydrous ethanol, and 30 μL of Nafion solution were added, and ultrasonication was performed for 30 min to make it evenly dispersed.

[0067] Step 3: Catalyst coating:

[0068] Use silicone rubber to draw an area of ​​2*2cm on the catalyst layer side of the cut gas diffusion electrode. 2 The dispersed dispersion is applied to the area, 160 μL of the dispersion is applied each time, and the dispersion is placed in an oven to dry. The application is repeated four times, and the dispersion is dried for later use.

[0069] Physical picture of cathode 2 electrode and NiSe 2 XRD and SEM Figure 4 and Figure 5 As shown, Figure 5 (a) XRD shows that NiSe 2 The characteristic diffraction peaks of Figure 5 (b) SEM shows that NiSe 2 It has a regular octahedral configuration.

[0070] The activity of cathode 2 in electrochemically reducing oxygen to produce hydrogen peroxide is as follows Fig.11 As shown in the figure, it can be seen that the cathode hydrogen peroxide production gradually increases as the cathode potential moves toward a negative value, that is, the hydrogen peroxide production increases with the increase of cathode current density. And the Faraday efficiency of generating hydrogen peroxide is higher in a wider potential range, that is, with a higher H 2 O 2 The selectivity indicates that the cathode has good two-electron oxygen reduction activity.

[0071] Example 3: Construction and operation of a device for preparing hydrogen peroxide by self-powered hydrazine hydrate oxidation:

[0072] The electrodeposited Ru / Co(OH) prepared in Example 1 2 The nickel foam electrode is used as the anode 6, and the NiSe coated electrode prepared in Example 2 is 2 The gas diffusion electrode of the dispersion is used as cathode 2, such as Figure 2 As shown, the gas diffusion chamber, cathode, cathode plate, proton exchange membrane, anode plate, anode, and clamp are stacked in sequence and clamped. The cavity formed by the cathode plate, cathode and proton exchange membrane is the cathode chamber, and the cavity formed by the proton exchange membrane, anode plate and anode is the anode chamber, forming a three-chamber flow reaction cell. A gasket can be set on both sides of the anode, cathode and proton exchange membrane, which can play a better role in sealing and preventing leakage after clamping. The cathode is NiSe 2The gas diffusion electrode of the catalytic layer is used to efficiently reduce oxygen to hydrogen peroxide. It is located between the cathode chamber and the gas diffusion chamber. The cathode electrolyte in the cathode chamber can directly contact the cathode; the anode is the electrodeposited Ru / Co(OH) 2 The nickel foam electrode, the Ru / Co(OH) 2 It has a nanosheet structure, and Ru is evenly distributed in the form of single atoms in Co(OH) 2 The surface is used for efficiently oxidizing hydrazine hydrate and is arranged between the anode chamber and the clamping plate. The anode electrolyte in the anode chamber can directly contact the anode; the cathode and the anode are connected by a wire; the proton exchange membrane is arranged between the cathode chamber and the anode chamber to block the cathode electrolyte and the anode electrolyte to avoid direct contact between the two, and also has the function of conducting protons, ensuring the effective separation of the components in the reaction cell and the smooth progress of the reaction.

[0073] System schematic diagram Figure 1 As shown. It includes an electrochemical reactor, a circulating feeding device and a gas conveying device. In the electrochemical reactor, a gas diffusion chamber 1, a cathode 2, a cathode chamber 3, a proton exchange membrane 4, an anode chamber 5 and an anode 6 are arranged in sequence. Among them, the gas diffusion layer of the cathode faces the gas diffusion chamber 1, and the catalytic layer faces the cathode chamber 3; titanium foil is placed on the cathode 2 and the anode 6, so that it is in contact with the electrode sheet and partially exposed outside the reactor, so that the positive and negative electrodes are coupled through wires in the subsequent process, and then the titanium foils at the positive and negative electrodes are connected through wires to obtain an electrochemical reactor.

[0074] The circulating feeding device includes a cathode circulating buffer tank 7, an anode circulating buffer tank 8 and a conveying device; the cathode chamber 3 is connected to the cathode circulating buffer tank 7 through a conveying pipeline, and the cathode electrolyte is circulated between the cathode chamber and the cathode circulating buffer tank; the anode chamber 3 is connected to the anode circulating buffer tank 8 through a conveying pipeline, and the anode electrolyte is circulated between the anode chamber and the anode circulating buffer tank; the peristaltic pump of the conveying equipment is arranged on the conveying pipeline.

[0075] The gas delivery device includes an oxygen cylinder 9 for delivering oxygen. The oxygen passes through the gas diffusion layer of the gas diffusion electrode in the gas diffusion chamber 1 to reach the catalytic layer on the cathode chamber side to react. The oxygen that does not pass through the gas diffusion layer flows back to the cathode circulation buffer tank through a pipeline.

[0076] 30mL of 0.05mol / L sulfuric acid solution is added to the cathode circulation buffer tank 7, and 30mL of a mixed solution of 1mol / L potassium hydroxide and 0.5mol / L hydrazine hydrate is added to the anode circulation buffer tank 8. The cathode circulation buffer tank 7 and the anode circulation buffer tank 8 are connected to the peristaltic pump and the cathode 2 and the anode 6 of the reactor respectively by pipelines. The electrolyte of the potassium hydroxide and hydrazine hydrate mixed solution is pumped from the anode circulation buffer tank 8 into the anode chamber 5, flows through the anode 6 from the bottom, and finally discharged from the upper end of the anode chamber 5 to the anode circulation buffer tank 8; the electrolyte of the sulfuric acid solution is pumped from the cathode ring buffer tank 7 into the cathode chamber 3, flows through the cathode 2 from the bottom, and finally discharged from the upper end of the cathode chamber 3 to the cathode circulation buffer tank 7; oxygen flows from the oxygen cylinder 9 through the gas flow controller 10 from the bottom of the gas diffusion chamber 1, part of the gas flows to the cathode side catalyst layer through the diffusion electrode, and the remaining gas flows into the cathode circulation buffer tank 7. The flow rate of the cathode and anode electrolytes was controlled to 100 mL / min by controlling the rotation speed of the peristaltic pump, and the flow rate of oxygen was adjusted to 30 mL / min by the gas flow controller 10.

[0077] When the electrolytes of the positive and negative electrodes start to circulate, oxygen is connected, and the positive and negative electrodes are connected by wires, the system starts to operate. The actual picture of the operating device is as follows: Figure 3 As shown, it can be observed that bubbles are generated on the anode 6 electrode sheet, and at the same time, an efficient two-electron oxygen reduction reaction begins on the cathode side, and the concentration of hydrogen peroxide begins to accumulate gradually.

[0078] During the operation of the system, the open circuit potential of the system can be measured by the electrochemical workstation. Fig.12 As shown in Figure 2, the system can reach an open circuit potential of 1.61 V. The discharge curve of the system is shown in Figure 2. Fig.13 As shown, the system can reach 3.58 mW cm -2 The peak power density is 2.38kWh. It is precisely because the starting potential of the anode reaction is lower than that of the cathode that the electrons spontaneously transfer from the anode to the cathode, thereby observing the discharge phenomenon, making the coupled system self-powered to prepare hydrogen peroxide without the need for external power drive.

[0079] During the operation of the system, the concentration of hydrogen peroxide can be detected. A small amount of electrolyte can be taken from the cathode circulation buffer tank 7 at regular intervals to detect the concentration of hydrogen peroxide therein. Fig.14 As shown, with the increase of time, the concentration of hydrogen peroxide on the cathode side of the self-powered system increases relatively linearly. After 10 hours of operation, the concentration of hydrogen peroxide in the system can reach 194mM.

[0080] This shows that the system can obtain a higher concentration of hydrogen peroxide without the need for electricity, reflecting the effectiveness of the method and device for preparing hydrogen peroxide with the assistance of hydrazine hydrate oxidation and self-power, greatly reducing the energy cost of hydrogen peroxide preparation, being environmentally friendly, and having great application potential.

[0081] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A device for preparing hydrogen peroxide by hydrazine hydrate oxidation-assisted self-power supply, characterized in that: The invention comprises an electrochemical reactor, a circulating feeding device and a gas conveying device. The electrochemical reactor comprises a gas diffusion chamber, a cathode, a cathode chamber, a proton exchange membrane, an anode chamber and an anode which are arranged in sequence. The cathode is a gas diffusion electrode with a NiSe2 catalyst layer attached thereto, which is used for efficiently reducing oxygen to hydrogen peroxide. The cathode is arranged between the cathode chamber and the gas diffusion chamber, and the cathode electrolyte in the cathode chamber can directly contact the cathode. The anode is a foamed nickel electrode on which Ru / Co(OH)2 is electrodeposited. The Ru / Co(OH)2 has a nano-sheet structure, and Ru is uniformly distributed on the surface of Co(OH)2 in the form of single atoms. The anode is used for efficiently oxidizing hydrazine hydrate. The cathode is arranged between the anode chamber and a clamping plate, and the anode electrolyte in the anode chamber can directly contact the anode. The cathode and the anode are connected by a wire. The circulating feeding device comprises a cathode circulating buffer tank, an anode circulating buffer tank and a conveying device; The gas delivery device includes an oxygen cylinder for delivering oxygen. The oxygen passes through the gas diffusion layer of the gas diffusion electrode in the gas diffusion chamber to reach the catalytic layer on the cathode chamber side to react. The oxygen that does not pass through the gas diffusion layer flows back to the cathode circulation buffer tank through a pipeline. The cathode chamber is connected to the cathode circulation buffer tank through a conveying pipeline, and the cathode electrolyte is circulated between the cathode chamber and the cathode circulation buffer tank; the anode chamber is connected to the anode circulation buffer tank through a conveying pipeline, and the anode electrolyte is circulated between the anode chamber and the anode circulation buffer tank; the conveying equipment is arranged on the conveying pipeline.

2. The device according to claim 1, characterized in that: The gas diffusion layer of the cathode faces the gas diffusion chamber, and the catalytic layer faces the cathode chamber.

3. The device according to claim 1, characterized in that: Titanium foil is placed on the cathode and anode so that it is in contact with the electrode sheet and partially exposed outside the reactor so that the positive and negative electrodes can be coupled through wires later.

4. The device according to claim 1, characterized in that: A NiSe2 dispersion prepared by NiSe2 is coated on one side of the gas diffusion electrode catalyst to form a NiSe2 catalyst layer. The NiSe2 dispersion consists of NiSe2, deionized water, anhydrous ethanol, and Nafion stock solution.

5. The device according to claim 1, characterized in that: The preparation method of the Ru / Co(OH)2 nickel foam electrode is as follows: using nickel foam as a working electrode, a solution of cobalt nitrate and ruthenium trichloride as an electrolyte, a platinum electrode as a counter electrode, and a saturated calomel reference electrode, a three-electrode system is constructed, and a current-time curve is set. At a potential of -0.8V--1.2V, the reaction time is set to 600-900s to prepare a nickel foam electrode for electrodepositing Ru / Co(OH)2.

6. The device according to claim 1, characterized in that: The cathode electrolyte is a sulfuric acid electrolyte, and the anode electrolyte is a mixed solution of potassium hydroxide and hydrazine hydrate.

7. The device according to claim 1, characterized in that: A gas flow controller is provided on the gas delivery pipeline.

8. A method for preparing hydrogen peroxide by hydrazine hydrate oxidation assisted by self-power supply using the device according to claim 1, characterized in that: The method is implemented based on the device for preparing hydrogen peroxide with hydrazine hydrate oxidation assisted by self-power supply according to claim 1, and is used for continuously preparing hydrogen peroxide with self-power supply, comprising the following steps: The anode electrolyte is pumped into the anode chamber from the anode circulation buffer tank, flows through the anode from the bottom of the anode, and is finally discharged from the upper end of the anode chamber to the anode circulation buffer tank; the cathode electrolyte is pumped into the cathode chamber from the cathode ring buffer tank, flows through the cathode from the bottom of the cathode, and is finally discharged from the upper end of the cathode chamber to the cathode circulation buffer tank; oxygen flows in from the gas diffusion chamber, part of the gas flows through the cathode to the cathode side catalyst layer, and the remaining gas flows into the cathode circulation buffer tank. In this process, the cathode and the anode are connected by a wire, hydrazine hydrate is oxidized to nitrogen on the anode side, and the oxygen flowing into the gas diffusion chamber is reduced to hydrogen peroxide on the cathode surface, and the hydrogen peroxide is accumulated in the cathode circulation buffer tank.

9. The method according to claim 8, characterized in that: Oxygen uses high-purity oxygen, and the flow rate is controlled at 20-50mL / min.

10. The method according to claim 8, characterized in that: The flow rate of the electrolyte ranged from 50-200 mL / min.

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