Electrochemical hydrogen peroxide synthesis system capable of producing hydrogen peroxide at any time in air atmosphere

Abstract

The invention discloses an electrochemical hydrogen peroxide synthesis system capable of being used and produced at any time in an air atmosphere, which belongs to the technical field of electrochemical synthesis and comprises a cathode shell, a cathode, an anion exchange membrane, a solid electrolyte layer, a cation exchange membrane, a counter electrode and an anode shell which are sequentially overlapped, the cathode shell is provided with an air inlet and an air outlet; a membrane electrode solid electrolyte is placed in the solid electrolyte layer, and a pure water inlet and an H2O2 solution outlet are formed in the solid electrolyte layer; the anode shell is provided with an anolyte inlet and an anolyte outlet; the cathode is composed of a cathode catalyst, and specifically, the cathode catalyst is a functionalized XC-72 carbon black catalyst loaded with 8-12% of surface oxygen coverage rate; the anode is composed of an anode catalyst. The catalytic electrolysis technology is utilized, only water and electricity basic supply needs to be connected, oxygen in water and air can be converted into a pure hydrogen peroxide solution, and the bottleneck that in the prior art, dependence on high-purity oxygen is high, and the synthesis efficiency is low under the low-oxygen condition is broken through.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical synthesis, and particularly relates to an electrochemical hydrogen peroxide synthesis system that can produce hydrogen peroxide on demand in an air atmosphere. Background Art

[0002] With the acceleration of China's urbanization process and the improvement of residents' health awareness, the demand for disinfection products has increased significantly in the fields of medical treatment, drinking water safety, and public health emergencies. As a highly efficient and residue-free green disinfectant, hydrogen peroxide (H2O2) has been extended from traditional industrial fields to key livelihood scenarios such as drinking water treatment in remote areas and post-disaster environmental disinfection. However, the existing hydrogen peroxide supply chain heavily relies on centralized production and long-distance transportation, facing prominent problems such as difficult storage, high cost, and poor timeliness in remote areas with weak infrastructure, and it is difficult to meet the rapid response requirements of public health emergencies.

[0003] Currently, the traditional preparation method of hydrogen peroxide is the anthraquinone method. In this method, a large amount of organic solvents (such as heavy aromatic hydrocarbons, trioctyl phosphate, etc.) need to be recycled during the production process. Each ton of H2O2 produces about 3 tons of high chemical oxygen demand (COD) wastewater containing quinone derivatives, and the treatment cost accounts for more than 25% of the total production cost. The reaction system requires high-pressure hydrogen gas (>1MPa) and pure oxygen input. In addition, the produced H2O2 solution is a highly oxidizing hazardous chemical, and special containers and cold chain systems are required for transportation in remote areas, which further increases the operation and maintenance costs and potential safety hazards.

[0004] Currently, the electrocatalytic oxygen reduction (ORR) route can directly synthesize H2O2 to avoid the above problems. However, existing technologies mostly rely on high-purity oxygen supply. In remote areas without oxygen supply facilities, an additional air separation device or liquid oxygen storage tank needs to be configured, which will significantly increase the system complexity and operation and maintenance costs. At the same time, the cathode catalyst has problems such as mass transfer limitation and poor selectivity under low oxygen partial pressure, resulting in a sharp drop in the H2O2 production rate. These factors greatly limit the application of hydrogen peroxide electro-synthesis technology in remote areas without oxygen supply, so it is urgent to develop an efficient electrolysis system suitable for low-concentration oxygen sources. Summary of the Invention

[0005] Aiming at the problems of low selectivity, serious product decomposition, and short system life in the electro-synthesis of hydrogen peroxide by traditional proton exchange membrane electrolyzers (PEMs), the present invention provides an electrochemical hydrogen peroxide synthesis system that can produce hydrogen peroxide on demand in an air atmosphere. By using catalytic electrolysis technology, only by connecting to the basic water and electricity supply, water and oxygen in the air can be converted into pure hydrogen peroxide solution, breaking through the bottleneck of the strong dependence on high-purity oxygen and low synthesis efficiency under low oxygen conditions in the existing technology.

[0006] The technical solution adopted by the present invention is as follows:

[0007] An electrochemical hydrogen peroxide synthesis system that produces on-demand in an air atmosphere, comprising a cathode housing, a cathode, an anion exchange membrane, a solid electrolyte layer, a cation exchange membrane, a counter electrode, and an anode housing that are stacked in sequence;

[0008] The cathode housing has a gas diffusion groove and is provided with an air inlet and an air outlet;

[0009] The solid electrolyte layer has a through groove inside for placing the membrane electrode solid electrolyte, and is also provided with a pure water inlet and an H2O2 solution outlet;

[0010] The anode housing has a gas diffusion groove and is provided with an anode electrolyte inlet and an anode electrolyte outlet;

[0011] The cathode is composed of a cathode catalyst, and the cathode catalyst is specifically a functionalized XC-72 carbon black catalyst with a surface oxygen coverage rate of 8% - 12%;

[0012] The anode is composed of an anode catalyst.

[0013] Further, the anode catalyst is specifically one or more of iridium oxide, ruthenium oxide, titanium oxide, and iridium / ruthenium metal.

[0014] Further, the membrane electrode solid electrolyte is specifically one or more of styrene-divinylbenzene copolymer, Cs x H 3-x PW 12 O 40 , electrolyte ceramics, and 10wt% H3PO4 / polyvinylpyrrolidone gel.

[0015] Further, the material model of the anion exchange membrane is One or more of X37-50, German Fuma anion exchange membrane FAA-3-50, versogen piperion a-40, and ami-7001s.

[0016] Further, the material model of the cation exchange membrane is one or more of Nafion 115, Nafion 117, NafionNR211, Nafion NR212, Nafion HP, Nafion NC700, Nafion XL, Gore MX765.08, GoreM788.12, and Gore M735.18.

[0017] Furthermore, the cation exchange membrane can be replaced by a bipolar membrane, and its material model is one or more of Fumasep FBM, Xion BPM-Aquivion, Xion BPM-Dyneon, and Xion BPM-Durion.

[0018] Furthermore, the anolyte is specifically one or more of water, sulfuric acid solution, perchloric acid solution, phosphoric acid, sodium hydroxide, and potassium hydroxide.

[0019] Furthermore, in the cathode housing, the air flow rate is 20 - 50 sccm.

[0020] Furthermore, in the solid electrolyte layer, by changing the flow rate of the pure water introduced, the concentration of the generated H2O2 solution is adjusted; specifically, the lower the flow rate of the pure water, the higher the concentration of the H2O2 solution.

[0021] Furthermore, in the solid electrolyte layer, the flow rate of the pure water introduced is 2 - 100 mL / h, preferably 2 - 60 mL / h.

[0022] Furthermore, a solid electrolyte layer frame is provided at the outer edge of the solid electrolyte layer, which is used to surround the cathode housing and the anode housing to form a sealed structure, and the pure water inlet and the H2O2 solution outlet are located on the solid electrolyte layer frame.

[0023] Furthermore, sealing gaskets are provided between the edge area of the solid electrolyte layer frame and the cathode housing except for the gas diffusion grooves, and between the edge area of the solid electrolyte layer frame and the anode housing except for the gas diffusion grooves.

[0024] Furthermore, sealing gaskets are provided between the solid electrolyte layer frame and the cation exchange membrane, between the solid electrolyte layer frame and the anion exchange membrane, between the edge area of the anode housing except for the gas diffusion grooves and the cation exchange membrane, and between the edge area of the cathode housing except for the gas diffusion grooves and the anion exchange membrane.

[0025] Furthermore, the cathode catalyst can also be one or more of activated carbon, oxidized activated carbon, boron / nitrogen / sulfur-doped activated carbon, graphene, oxidized graphene, boron / nitrogen-doped graphene, carbon nanotubes, cobalt / manganese / platinum / palladium / gold single-atom catalysts supported on boron / nitrogen / sulfur-doped carbon, cobalt / manganese / platinum / palladium / gold single-atom catalysts supported on molybdenum sulfide, cobalt selenide, cobalt sulfide, palladium sulfide, palladium phosphide, platinum phosphide, gold-palladium alloy, gold-platinum alloy, platinum-mercury alloy, and palladium-mercury alloy supported on boron / nitrogen / sulfur-doped carbon / titanium dioxide.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] 1. The present invention proposes an electrochemical hydrogen peroxide synthesis system that produces hydrogen peroxide on demand in an air atmosphere. It uses air to form the product HO2 at the cathode reaction ﹣ , which diffuses into the solid electrolyte layer and recombines with the anode reaction product H + to synthesize H2O2. Then, the flowing pure water is used to timely carry out the synthesized system to obtain an H2O2 solution. The present invention can avoid the accumulation of products. At the same time, the solid electrolyte layer can independently regulate the pH of the anode and cathode to maintain a neutral reaction environment (pH = 7), improve the selectivity of H2O2 and inhibit its decomposition. In addition, the synthesis system adopts a structural design of an anion exchange membrane - solid electrolyte - cation exchange membrane, which can effectively avoid the cross-diffusion of H2O2 products to the anode and further improve the selectivity of H2O2;

[0028] 2. The present invention uses a functionalized XC-72 carbon black catalyst with a surface oxygen coverage rate of 8% - 12% as the cathode catalyst, which has high H2O2 catalytic activity, selectivity and stability.

[0029] 3. The present invention uses pure water and air as raw materials, breaking through the bottleneck of the strong dependence on high-purity oxygen and low synthesis efficiency under low-oxygen conditions in the existing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0031] Figure 1 It is the scanning electron microscope characterization diagram of the functionalized XC-72 carbon black catalyst with a surface oxygen coverage rate of 10.19% prepared in Example 1 of the present invention;

[0032] Figure 2 It is the X-ray diffraction spectrum characterization diagram of the functionalized XC-72 carbon black catalyst with a surface oxygen coverage rate of 10.19% prepared in Example 1 of the present invention;

[0033] Figure 3 It is the X-ray photoelectron spectroscopy characterization diagram of the functionalized XC-72 carbon black catalyst with a surface oxygen coverage rate of 10.19% prepared in Example 1 of the present invention;

[0034] Figure 4 It is the disassembly structure schematic diagram of the electrochemical hydrogen peroxide synthesis system that produces hydrogen peroxide on demand in an air atmosphere proposed in Examples 2 - 6 of the present invention;

[0035] Figure 5The Faradaic efficiency (FE) of the catalyst production at different current densities for the electrochemically synthesized hydrogen peroxide generation system that produces on-demand in an air atmosphere proposed in Embodiments 2-6 of the present invention. Detailed implementation manners

[0036] To further understand the present invention, the preferred embodiments of the present invention will be described below in conjunction with embodiments. However, it should be understood that these descriptions are only for further explaining the features and advantages of the present invention, rather than limiting the claims of the invention.

[0037] For all raw materials of the present invention, there is no particular limitation on their sources, and they can be purchased on the market or prepared by conventional methods well-known to those skilled in the art.

[0038] For all raw materials of the present invention, there is no particular limitation on their purity. The present invention preferably adopts analytical purity or the conventional purity requirements in the field of atomic layer deposition.

[0039] For all raw materials and process procedures of the present invention, their trade names or abbreviations are all conventional trade names or abbreviations in the art. Each trade name or abbreviation is clear and definite in the field of its related uses. Those skilled in the art can purchase them from the market or prepare them by conventional methods according to the trade name, abbreviation, and corresponding uses, or implement them using the corresponding equipment.

[0040] The present invention will be further described in detail below in conjunction with embodiments:

[0041] Embodiment 1

[0042] In this embodiment, a surface oxygen-functionalized XC-72 carbon black catalyst was prepared. The specific process was as follows:

[0043] 600 mg of commercial XC-72 carbon black was added to 600 mL of nitric acid with a concentration of 12.0 M, and then refluxed at 85 °C for 3 h to finally obtain oxidized carbon black with a surface oxygen content of 10.19%. After natural cooling, the slurry was taken out for centrifugation, and repeatedly washed with deionized water and absolute ethanol until neutral. Finally, it was dried in an oven at 70 °C to prepare a functionalized XC-72 carbon black catalyst with a surface oxygen coverage of 10.19%.

[0044] Next, the obtained functionalized XC-72 carbon black catalyst with a surface oxygen coverage of 10.19% was characterized.

[0045] Figure 1 is the scanning electron microscope characterization diagram of the obtained functionalized XC-72 carbon black catalyst with a surface oxygen coverage of 10.19%. Since the raw material commercial XC-72 carbon black is a porous structure, oxidation treatment will introduce a large number of defects, but it may also cause the collapse of the porous carbon black structure. Therefore, according to Figure 1It can be seen that the morphology of the carbon black catalyst after surface functionalization has not changed significantly.

[0046] Figure 2 This is the X-ray diffraction spectrum characterization diagram of the functionalized XC-72 carbon black catalyst with a surface oxygen coverage of 10.19% prepared in this example, indicating that no new phase is introduced after the surface functionalization of the carbon black catalyst.

[0047] Figure 3 This is the X-ray photoelectron spectroscopy (XPS) characterization diagram of the functionalized XC-72 carbon black catalyst with a surface oxygen coverage of 10.19% prepared in this example. It can be seen that the nitric acid oxidation treatment enriches oxygen-containing functional groups on the particle surface, including C-O-C / C-OH and HO-C=O. These signals are separated from the 1s spectra of carbon and oxygen, further indicating that the nitric acid oxidation treatment successfully induces the surface oxygen functionalization of the carbon black catalyst, and the surface oxygen functionalization will help improve the catalytic activity, selectivity, and stability of H2O2.

[0048] Example 2

[0049] This example proposes an electrochemical hydrogen peroxide synthesis system that produces hydrogen peroxide on demand in an air atmosphere. The structure is as Figure 4 shown, including a cathode housing, a cathode, an anion exchange membrane, a solid electrolyte layer, a cation exchange membrane, a counter electrode, and an anode housing stacked in sequence.

[0050] The cathode housing has a gas diffusion groove and is provided with an air inlet and an air outlet.

[0051] The anode housing has a gas diffusion groove and is provided with an anode electrolyte inlet and an anode electrolyte outlet.

[0052] The solid electrolyte layer has a through groove inside for placing the membrane electrode solid electrolyte, and the membrane electrode solid electrolyte is specifically a styrene-divinylbenzene copolymer; the outer edge of the solid electrolyte layer is provided with a solid electrolyte layer frame for surrounding the cathode housing and the anode housing to form a sealed structure, and a pure water inlet and a H2O2 solution outlet are provided on the solid electrolyte layer frame; sealing gaskets are provided between the edge area of the solid electrolyte layer frame and the cathode housing except for the gas diffusion groove, and between the edge area of the solid electrolyte layer frame and the anode housing except for the gas diffusion groove.

[0053] The cathode is composed of a cathode catalyst, and the cathode catalyst is specifically the functionalized XC-72 carbon black catalyst with a surface oxygen coverage of 10.19% obtained in Example 1.

[0054] The anode is composed of an anode catalyst, and the anode catalyst is specifically iridium oxide.

[0055] The anion exchange membrane is specifically the bipolar membrane Fumasep FBM.

[0056] The cation exchange membrane is specifically the Nafion membrane.

[0057] In this embodiment, deionized water is used as the anolyte, and the flow rate of the anolyte is set to 2 mL / min; the air flow rate is set to 50 sccm; the pure water flow rate introduced into the solid electrolyte layer is 1 mL / min.

[0058] This embodiment uses the constant current method for testing, and the applied current density is -10 mA / cm 2 , and the obtained product is colored with titanium sulfate and detected by ultraviolet absorption spectroscopy. Combining with the data of the electrochemical workstation, the Faraday efficiency of the product is obtained as 76.57%.

[0059] Example 3

[0060] This embodiment proposes an electrochemical hydrogen peroxide synthesis system that generates hydrogen peroxide on demand in an air atmosphere. The structure is exactly the same as that of Example 2, except that when using the constant current method for testing, the current density is adjusted to -20 mA / cm 2 , and the detected Faraday efficiency of the product is 76.67%.

[0061] Example 4

[0062] This embodiment proposes an electrochemical hydrogen peroxide synthesis system that generates hydrogen peroxide on demand in an air atmosphere. The structure is exactly the same as that of Example 2, except that when using the constant current method for testing, the current density is adjusted to -30 mA / cm 2 , and the detected Faraday efficiency of the product is 80.76%.

[0063] Example 5

[0064] This embodiment proposes an electrochemical hydrogen peroxide synthesis system that generates hydrogen peroxide on demand in an air atmosphere. The structure is exactly the same as that of Example 2, except that when using the constant current method for testing, the current density is adjusted to -40 mA / cm 2 , and the detected Faraday efficiency of the product is 81.63%.

[0065] Example 6

[0066] This embodiment proposes an electrochemical hydrogen peroxide synthesis system that generates hydrogen peroxide on demand in an air atmosphere. The structure is exactly the same as that of Example 2, except that when using the constant current method for testing, the current density is adjusted to -50 mA / cm 2 , and the detected Faraday efficiency of the product is 83.32%.

[0067] Figure 5For the catalyst yield FE at different current densities of the on-demand electrochemically synthesized hydrogen peroxide system in an air atmosphere proposed in Examples 2 to 6, it can be seen that the proposed on-demand electrochemically synthesized hydrogen peroxide system in an air atmosphere has excellent H2O2 selectivity, and as the current density increases, the H2O2 yield also gradually increases.

[0068] Example 7

[0069] In this example, an on-demand electrochemically synthesized hydrogen peroxide system in an air atmosphere is proposed. Compared with Example 2, the only difference in the structure is that the setting position of the sealing gasket is adjusted. Specifically, the adjustment is as follows: sealing gaskets are provided between the frame of the solid electrolyte layer and the cation exchange membrane, between the frame of the solid electrolyte layer and the anion exchange membrane, between the edge region of the anode housing except for the gas diffusion groove and the cation exchange membrane, and between the edge region of the cathode housing except for the gas diffusion groove and the anion exchange membrane. Other structures remain unchanged.

[0070] The above is a detailed introduction to the nickel phthalocyanine molecular catalyst constructed on the surface of an oxygen-doped carbon material proposed by the present invention, its preparation method and application. In this article, specific examples are used to elaborate on the principle and implementation manner of the present invention. The description of the above examples is only used to help understand the method and its core idea of the present invention, including the best mode, and also enables any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The protection scope of the present invention patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the literal description of the claims, or if they include equivalent structural elements that have no substantial difference from the literal description of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. An electrochemically synthesized hydrogen peroxide system that produces hydrogen peroxide on demand in an air atmosphere, characterized in that, It includes a cathode housing, a cathode, an anion exchange membrane, a solid electrolyte layer, a cation exchange membrane, a counter electrode, and an anode housing that are stacked in sequence; The cathode housing has a gas diffusion groove, and is provided with an air inlet and an air outlet; The solid electrolyte layer has a through groove inside for placing the membrane electrode solid electrolyte, and is also provided with a pure water inlet and an H2O2 solution outlet; The anode housing has a gas diffusion groove, and is provided with an anode electrolyte inlet and an anode electrolyte outlet; The cathode is composed of a cathode catalyst, and the cathode catalyst is specifically a functionalized XC-72 carbon black catalyst with a surface oxygen coverage rate of 8% to 12%; The anode is composed of an anode catalyst.

2. The electrochemical hydrogen peroxide synthesis system for on-demand production in an air atmosphere according to claim 1, wherein The anode catalyst is specifically one or more of iridium oxide, ruthenium oxide, titanium oxide, and iridium / ruthenium metal.

3. The electrochemical hydrogen peroxide synthesis system for on-demand production in an air atmosphere according to claim 1, wherein The membrane electrode solid electrolyte is specifically one or more of styrene-divinylbenzene copolymer, Cs x H 3-x PW 12 O 40 , electrolyte ceramics, 10wt% H3PO4 / polyvinylpyrrolidone gel.

4. The electrochemically synthesized hydrogen peroxide system that generates on-demand in an air atmosphere according to claim 1, wherein The anode electrolyte is specifically one or more of water, sulfuric acid solution, perchloric acid solution, phosphoric acid, sodium hydroxide, and potassium hydroxide.

5. The electrochemical hydrogen peroxide synthesis system for on-demand production in an air atmosphere according to claim 1, wherein In the cathode housing, the air flow rate is 20 to 50 sccm.

6. The electrochemical hydrogen peroxide synthesis system that produces on-demand in an air atmosphere according to claim 1, wherein, In the solid electrolyte layer, the pure water flow rate is 2 to 100 mL / h.

7. The electrochemical hydrogen peroxide synthesis system for on-demand production in an air atmosphere according to claim 1, wherein The outer edge of the solid electrolyte layer is provided with a solid electrolyte layer frame for surrounding the cathode housing and the anode housing to form a sealed structure, and the pure water inlet and the H2O2 solution outlet are located on the solid electrolyte layer frame.

8. The electrochemically synthesized hydrogen peroxide system for on-demand production in an air atmosphere according to claim 7, wherein, Sealing gaskets are provided between the solid electrolyte layer frame and the edge area of the cathode housing other than the gas diffusion groove, and between the solid electrolyte layer frame and the edge area of the anode housing other than the gas diffusion groove.

9. The electrochemically synthesized hydrogen peroxide production system that produces hydrogen peroxide as needed under an air atmosphere according to claim 7, wherein Sealing gaskets are provided between the solid electrolyte layer frame and the cation exchange membrane, between the solid electrolyte layer frame and the anion exchange membrane, between the edge area of the anode housing other than the gas diffusion groove and the cation exchange membrane, and between the edge area of the cathode housing other than the gas diffusion groove and the anion exchange membrane.

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