Membrane electrode for preparing hydrogen peroxide by oxygen reduction, preparation method thereof and membrane electrode reactor

Abstract

The present application relates to a membrane electrode for preparing hydrogen peroxide by oxygen reduction, a preparation method thereof and a membrane electrode reactor. The membrane electrode comprises a cathode diffusion electrode, a cation exchange membrane and an anode oxygen evolution electrode arranged in a stacked manner, the cation exchange membrane is located between the cathode diffusion electrode and the anode oxygen evolution electrode, and the cathode diffusion electrode, the cation exchange membrane and the anode oxygen evolution electrode are physically connected to each other; the cathode diffusion electrode comprises a cathode porous substrate layer and a cathode active layer, the cathode active layer comprises a cathode catalyst and a cation regulating substance, and the anode oxygen evolution electrode comprises an anode porous substrate layer and an anode active layer, the anode active layer comprises an anode catalyst. The membrane electrode can be used for preparing hydrogen peroxide by oxygen reduction, and has good selectivity for hydrogen peroxide and high Faraday efficiency.

Description

Technical Field

[0001] The present application relates to the technical field of electrocatalysis and electrochemical reactors, and in particular to a membrane electrode for preparing hydrogen peroxide by oxygen reduction, a preparation method thereof, and a membrane electrode reactor. Background Art

[0002] As a clean oxidant, hydrogen peroxide affects many industries such as disinfection, water treatment, chemical synthesis, and paper bleaching. The electrochemical oxygen reduction method is highly environmentally friendly and can rely on the development advantages of green electricity technology. The raw materials are water, oxygen, or air. Driven by electric energy, a two-electron electrocatalytic oxygen reduction reaction occurs to generate an aqueous hydrogen peroxide solution, which is green, clean, and efficient, and can meet the needs of miniaturization and discrete manufacturing.

[0003] At present, most of the electrosynthesis processes of hydrogen peroxide are carried out in electrolyte solutions. The resulting aqueous hydrogen peroxide solution contains a large amount of electrolytes such as acids, alkalis or salts, requiring high-cost separation and purification to obtain pure aqueous hydrogen peroxide solution. Some solution systems also have a major hidden danger of hydrogen peroxide decomposition, which is not conducive to safe production.

[0004] Therefore, how to obtain a purer aqueous hydrogen peroxide solution and resolve potential safety hazards is an urgent problem to be solved. Summary of the invention

[0005] Based on this, it is necessary to provide a membrane electrode for preparing hydrogen peroxide by oxygen reduction, a preparation method thereof, and a membrane electrode reactor, which can prepare hydrogen peroxide in a pure water environment to obtain purer hydrogen peroxide, and use the membrane electrode to generate hydrogen peroxide to improve hydrogen peroxide selectivity and Faraday efficiency.

[0006] In one aspect of the present application, a membrane electrode for preparing hydrogen peroxide by oxygen reduction is provided, comprising a cathode diffusion electrode, a cation exchange membrane and an anode oxygen evolution electrode arranged in a stacked manner, wherein the cation exchange membrane is located between the cathode diffusion electrode and the anode oxygen evolution electrode, and the cathode diffusion electrode, the cation exchange membrane and the anode oxygen evolution electrode are interconnected in a physical manner;

[0007] The cathode diffusion electrode comprises a cathode porous substrate layer and a cathode active layer, wherein the cathode active layer comprises a cathode catalyst and a cation regulating substance; the anode oxygen evolution electrode comprises an anode porous substrate layer and an anode active layer, wherein the anode active layer comprises an anode catalyst.

[0008] In some embodiments, the cation regulating substance comprises a cationic polymer and / or a crown ether complexed with a metal ion; and / or, the cathode catalyst is one or more of an oxidized carbon material, a metal single atom doped carbon material, and a metal nanocluster doped carbon material.

[0009] In some specific embodiments, the cationic polymer includes one or more of Fumasep anion exchange resin, Alykmer anion exchange resin, Piperion anion exchange resin, Sustainion anion exchange resin, quaternized polyethyleneimine, cross-linked polydiallyldimethylammonium chloride, quaternary ammonium poly(n-methyl-piperidine-co-p-terphenyl), quaternary amino poly(arylperfluoroalkylene), poly(terphenylpiperidinium-trifluoroacetophenone), poly(diphenyl-co-terphenylpiperidinium) (PDTP), branched poly(terphenylpiperidinium), and poly(fluorenyl-co-terphenylpiperidinium) (PFAP).

[0010] In some specific embodiments, the metal ion complexed crown ether includes one or more of 18-crown-6 complexed with sodium ions, 15-crown-5 complexed with potassium ions, and 12-crown-4 complexed with sodium ions.

[0011] In some embodiments, the oxidized carbon material comprises one or more of oxidized graphene, oxidized carbon nanotubes and oxidized carbon black; and / or,

[0012] The metal single atom doped carbon material includes Co and Fe single atom doped carbon material; and / or,

[0013] The metal nanocluster doped carbon material includes one or more of a Ni nanocluster doped carbon material, a Cu nanocluster doped carbon material and a Fe nanocluster doped carbon material.

[0014] In some embodiments, the cathode catalyst loading in the cathode diffusion electrode is 0.05-5 mg / cm 2 The cathode diffusion electrode has a cation regulating substance loading of 1 to 500 μg / cm 2 electrode.

[0015] In some embodiments, the mass ratio of the cathode catalyst to the cation regulating substance in the cathode diffusion electrode is 1:(0.0016~0.06), preferably 1:(0.0032~0.06).

[0016] In some embodiments, the anode catalyst includes one or more of iridium oxide, ruthenium oxide, rhodium oxide, iron oxide, cobalt oxide, nickel oxide, perovskite oxide, NiFe oxide, NiFe hydroxide, iron sulfide, cobalt sulfide, nickel sulfide, copper sulfide, manganese sulfide, Ni phosphide and Fe phosphide.

[0017] In some embodiments, the loading amount of the anode catalyst in the anode oxygen evolution electrode is 0.05-20 mg / cm 2 electrode.

[0018] In some embodiments, the cathode active layer includes a cathode catalyst layer and a cation regulating material layer.

[0019] In some embodiments, the porosity of the cathode porous substrate layer is 20% to 80%. Optionally, the cathode porous substrate layer is carbon paper or carbon cloth;

[0020] And / or, the porosity of the anode porous substrate layer is 20% to 80%. Optionally, the anode porous substrate layer is carbon paper, carbon cloth, metal mesh or foam metal.

[0021] In some embodiments, the cation exchange membrane has a thickness of 10 μm to 300 μm. Optionally, the cation exchange membrane is a Nafion membrane.

[0022] In another aspect of the present application, a membrane electrode is provided, comprising the following steps:

[0023] Step S10, loading the cathode catalyst and the cation regulating substance on the cathode porous substrate layer to obtain the cathode diffusion electrode;

[0024] Step S20, loading the anode catalyst on the anode porous substrate layer to obtain the anode oxygen evolution electrode; and

[0025] Step S30, stacking the cathode diffusion electrode, the cation exchange membrane and the anode oxygen evolution electrode in sequence.

[0026] In some embodiments, step S10 includes:

[0027] Step S11, mixing the cathode catalyst and the cation regulating substance in a solvent to obtain a mixed coating;

[0028] Step S13, coating the mixed coating on the cathode porous substrate layer.

[0029] In some embodiments, step S10 includes:

[0030] Step S12, placing the cathode catalyst in a solvent to obtain a cathode catalyst coating;

[0031] Step S14, coating the cathode catalyst coating on the cathode porous substrate layer to form a cathode catalyst layer;

[0032] Step S16, placing the cationic regulating substance in a solvent to obtain a cationic regulating substance coating;

[0033] Step S18, coating the cation regulating substance coating on the cathode catalyst layer to form a cation regulating substance layer.

[0034] Another aspect of the present application provides a membrane electrode reactor, comprising the membrane electrode.

[0035] Compared with the prior art, this application has at least the following beneficial effects:

[0036] Compared with the traditional membrane electrode, the membrane electrode provided by the present application adds a cation regulating substance at the cathode, changes the cathode interface state, blocks a large number of protons migrating from the anode, and reduces the proton concentration on the cathode catalyst surface, so that the membrane electrode can accelerate the OOH reaction when the electrochemical reaction occurs in pure water. - Ion migration inhibits the 4-electron reduction reaction of oxygen to produce water, thereby improving the selectivity of hydrogen peroxide (Faraday efficiency).

[0037] The membrane electrode used in the present application has the characteristics of simple structure and good stability. The cation regulating substance used can form a three-dimensional ion conduction network structure with the catalyst layer. The electrolytic cell has small ion conduction resistance, low cell voltage and low energy consumption.

[0038] The membrane electrode reactor provided in the present application uses pure water, oxygen or air as raw materials, does not use electrolyte solution, the process is green and clean, and the produced hydrogen peroxide can meet the needs of disinfection, drifting and other processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 is a schematic structural diagram of a membrane electrode according to an embodiment;

[0041] Figure 2 is a schematic structural diagram of a cathode diffusion electrode according to an embodiment;

[0042] Figure 3 It is a schematic structural diagram of an anode oxygen evolution electrode according to one embodiment;

[0043] Figure 4 is a schematic structural diagram of a cathode active layer according to one embodiment;

[0044] Figure 5 The figure is a schematic diagram of the structure of a reaction system for preparing hydrogen peroxide by oxygen reduction according to one embodiment.

[0045] Among them, the figure numbers are:

[0046] 10-cathode diffusion electrode, 20-cation exchange membrane, 30-anode oxygen evolution electrode, 12-cathode porous substrate layer, 14-cathode active layer, 32-anode porous substrate layer, 34-anode active layer, 141-cathode catalyst layer, 142-cation regulating material layer, 1-oxygen or air feed pipeline, 2-cathode pure water feed pipeline, 3-gas-liquid mixer, 4-back pressure valve, 5-cathode outlet pipeline, 6-membrane electrode, 7-cathode flow channel chamber, 8-anode flow channel chamber, 9-electrochemical workstation (power supply), 10-anode pure water inlet pipeline, 11-anode outlet pipeline. DETAILED DESCRIPTION

[0047] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0049] In this application, "first aspect", "second aspect", "third aspect", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features.

[0050] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0051] In the present application, "one or more" refers to any one, any two, or any two or more of the listed items.

[0052] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0053] The percentage contents involved in this application, unless otherwise specified, refer to mass percentage for solid-liquid mixing and solid-solid mixing, and refer to volume percentage for liquid-liquid mixing.

[0054] The percentage concentrations mentioned in this application, unless otherwise specified, refer to the final concentration, which refers to the percentage of the added component in the system after the addition of the component.

[0055] The temperature parameters in this application, unless otherwise specified, allow for both constant temperature treatment and treatment within a certain temperature range. The constant temperature treatment allows the temperature to fluctuate within the accuracy range of instrument control.

[0056] In the present application, the method steps that do not emphasize the temperature usually refer to the method steps performed at normal temperature or room temperature. In this article, normal temperature and room temperature are equivalent and interchangeable, and the specific temperature refers to 22°C to 25°C.

[0057] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0058] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0059] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0060] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0061] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0062] Membrane electrode reactor is an important reaction device for preparing hydrogen peroxide in a pure water environment. The electrolyte in this type of reactor is replaced by a cationic regulating substance, which can obtain purer hydrogen peroxide. Advanced membrane electrodes are the key to preparing hydrogen peroxide, especially for efficient synthesis of hydrogen peroxide.

[0063] Due to the destructive effect of rapid electrowetting on the reactive three-phase interface of air diffusion electrodes under high current density operating conditions, the industrial conversion of this electrochemical two-electron oxygen reduction to produce hydrogen peroxide is challenged by poor selectivity and durability. In particular, the Faradaic efficiency of existing membrane electrodes for oxygen reduction to produce hydrogen peroxide still needs to be improved.

[0064] Therefore, the first aspect of the present application provides a membrane electrode for preparing hydrogen peroxide by oxygen reduction, see Figure 1 , which comprises a cathode diffusion electrode 10, a cation exchange membrane 20 and an anode oxygen evolution electrode 30 which are stacked, wherein the cation exchange membrane 20 is located between the cathode diffusion electrode 10 and the anode oxygen evolution electrode 30, and the cathode diffusion electrode 10, the cation exchange membrane 20 and the anode oxygen evolution electrode 30 are connected to each other in a physical manner. Figure 2 The cathode diffusion electrode 10 includes a cathode porous substrate layer 12 and a cathode active layer 14. The cathode active layer 14 contains a cathode catalyst and a cation regulating substance.

[0065] See also Figure 3 The anode oxygen evolution electrode 30 includes an anode porous substrate layer 32 and an anode active layer 34, and the anode active layer 34 contains an anode catalyst.

[0066] The cation exchange resin mentioned above includes a cation exchange resin.

[0067] It should be noted that the cathode diffusion electrode 10, the cation exchange membrane 20 and the anode oxygen evolution electrode 30 are connected to each other in a physical connection, and the physical connection is a non-embedded physical connection, that is, the cathode diffusion electrode 10 and the cation exchange membrane 20 are in physical contact or close physical contact, and the close physical contact is limited to the contact between the two, which means that the contact effect is better, that is, all the contactable surfaces of the two are tightly fitted, and they are all in contact on the macroscopic structure, rather than partial or complete fusion, mutual penetration or mutual embedding of the two in terms of molecular structure.

[0068] For example, when heat treatment is used to combine the cathode diffusion electrode and the cation exchange membrane, it causes at least part of the cation regulating substance and the cation exchange resin in the cation exchange membrane to fuse, penetrate or embed with each other, which affects the migration of protons and increases the proton concentration on the cathode catalyst, which goes against the purpose of the present application.

[0069] In some embodiments, the cation modulating substance is a cationic polymer and / or a crown ether complexed with a metal ion.

[0070] Optionally, the cationic polymer includes one or more of an ammonium polymer resin, an imidazolium polymer resin, a phosphonium and an organic metal cationic polymer resin, and further optionally, specific examples of the cationic polymer include, but are not limited to, Fumasep anion exchange resin, Alykmer anion exchange resin, Piperion anion exchange resin, Sustainion anion exchange resin, quaternized polyethyleneimine, cross-linked polydiallyldimethylammonium chloride, quaternary ammonium poly (n-methyl-piperidine-co-p-terphenyl), quaternary amino poly (aryl perfluoroalkylene), poly (terphenyl piperidinium-trifluoroacetophenone), poly (diphenyl-co-terphenyl piperidinium) (PDTP), branched poly (terphenyl piperidinium) and poly (fluorenyl-co-terphenyl piperidinium) (PFAP) and combinations thereof.

[0071] The main component of Fumasep anion exchange resin is polysulfone quaternary ammonium salt polymer. The main component of Alykmer anion exchange resin is polyaryl piperidine. The main component of Piperion anion exchange resin is polyaryl piperidine. The main component of Sustainion anion exchange resin is imidazole-functionalized polystyrene.

[0072] Optionally, the metal ion-complexed crown ether includes one or more of 18-crown-6 complexed with sodium ions, 15-crown-5 complexed with potassium ions, and 12-crown-4 complexed with sodium ions.

[0073] In some embodiments, the cathode catalyst is an oxidized carbon material, a metal single atom doped carbon material, or a metal nanocluster doped carbon material.

[0074] Optionally, the oxidized carbon material includes one or more of oxidized graphene, oxidized carbon nanotubes and oxidized carbon black.

[0075] Optionally, the metal single atom doped carbon material includes Co or Fe single atom doped carbon material.

[0076] Optionally, the metal nanocluster-doped carbon material includes one or more of a Ni nanocluster-doped carbon material, a Cu nanocluster-doped carbon material, and a Fe nanocluster-doped carbon material.

[0077] Further optionally, the carbon material includes one or more of carbon black, graphene, carbon nanotubes, oxidized carbon black, oxidized graphene, and oxidized carbon nanotubes.

[0078] In some embodiments, the cathode catalyst loading in the cathode diffusion electrode 10 is 0.05-5 mg / cm 2 Electrode, for example, may be comprised of but not limited to 0.05 mg / cm 2 Electrode, 0.1 mg / cm 2 Electrode, 0.5 mg / cm 2 Electrode, 1mg / cm 2 Electrode, 1.5 mg / cm 2 Electrode, 2 mg / cm 2 Electrode, 2.5 mg / cm 2 Electrode, 3 mg / cm 2 Electrode, 3.5 mg / cm 2 Electrode, 4 mg / cm 2 Electrode, 4.5 mg / cm 2 Electrode, 5 mg / cm 2 electrode and the range between any two of the above values.

[0079] In some embodiments, the loading amount of the cation regulating substance in the cathode diffusion electrode 10 is 1-500 μg / cm 2 Electrode, for example, but not limited to 1 μg / cm 2 Electrode, 10μg / cm 2 Electrode, 50μg / cm 2 Electrode, 100 μg / cm 2 Electrode, 150μg / cm 2 Electrode, 200μg / cm 2 Electrode, 250μg / cm 2 Electrode, 300μg / cm 2 Electrode, 350μg / cm 2 Electrode, 400μg / cm2 Electrode, 450μg / cm 2 Electrode, 500μg / cm 2 electrode and the range between any two of the above values.

[0080] In some embodiments, the mass ratio of the cathode catalyst to the cation regulating substance in the cathode diffusion electrode 10 is 1: (0.0016-0.06), for example, it may be but not limited to 1: 0.0016, 1: 0.0018, 1: 0.002, 1: 0.003, 1: 0.0032, 1: 0.005, 1: 0.01, 1: 0.016, 1: 0.02, 1: 0.03, 1: 0.04, 1: 0.048, 1: 0.05, 1: 0.06 and the range between any two of the above ratios. Optionally, the mass ratio of the cathode catalyst to the cation regulating substance in the cathode diffusion electrode 10 is 1: (0.0032-0.06), and further can be 1: (0.01-0.06). Within this optional range, the proton concentration on the surface of the cathode catalyst is more conducive to the production of hydrogen peroxide, the selectivity of hydrogen peroxide is better, and the farad rate effect of the membrane electrode reactor is higher.

[0081] In some embodiments, the cathode active layer 14 is formed by drying a mixed coating comprising a cathode catalyst and a cation regulating substance, and the cathode catalyst and the cation regulating substance do not form obvious stratification.

[0082] In some other embodiments, see Figure 4 The cathode active layer 14 is a composite layer including a cathode catalyst layer 141 and a cation regulating material layer 142. The cathode catalyst layer 141 is arranged close to the cathode porous substrate layer 12, and the cation regulating material layer 142 is arranged away from the cathode porous substrate layer 12. The cathode catalyst layer is formed by drying a coating containing only the cathode catalyst, and the cation regulating material layer is formed by drying a coating containing only the cation regulating material. The proton concentration on the surface of the membrane electrode cathode catalyst of this embodiment is lower, the selectivity of hydrogen peroxide is better, and the Faraday efficiency of the membrane electrode reactor is higher.

[0083] In some embodiments, the porosity of the cathode porous substrate layer 12 is 20% to 80%, for example, but not limited to, 20%, 30%, 40%, 50%, 60%, 70%, 80% and ranges between any two of the above values.

[0084] In some embodiments, cathode porous substrate layer 12 is carbon paper or carbon cloth.

[0085] In some embodiments, the porosity of the anode porous substrate layer 12 is 20% to 80%, for example, but not limited to, 20%, 30%, 40%, 50%, 60%, 70%, 80% and ranges between any two of the above values.

[0086] In some embodiments, the anode porous substrate layer 32 is carbon paper, carbon cloth, metal mesh or foamed metal. Specific examples of metal mesh or foamed metal include titanium mesh, nickel mesh, foamed nickel and stainless steel mesh.

[0087] In some embodiments, the anode catalyst includes one or more of iridium oxide, ruthenium oxide, rhodium oxide, iron oxide, cobalt oxide, nickel oxide, perovskite oxide, NiFe oxide, NiFe hydroxide, iron sulfide, cobalt sulfide, nickel sulfide, copper sulfide, manganese sulfide, Ni phosphide, and Fe phosphide.

[0088] The loading amount of the anode catalyst in the anode oxygen evolution electrode 30 can be 0.05-20 mg / cm 2 Electrode, for example, but not limited to 0.05 mg / cm 2 Electrode, 0.1 mg / cm 2 Electrode, 0.5 mg / cm 2 Electrode, 1mg / cm 2 Electrode, 5 mg / cm 2 Electrode, 10mg / cm 2 Electrode, 15 mg / cm 2 Electrode, 20 mg / cm 2 electrode and the range between any two of the above values.

[0089] In some embodiments, the anode porous substrate layer 32 is carbon paper or carbon cloth, and the loading amount of the anode catalyst in the anode oxygen evolution electrode 30 is 0.05-5 mg / cm 2 Electrode, for example, but not limited to 0.05 mg / cm 2 Electrode, 0.1 mg / cm 2 Electrode, 0.5 mg / cm 2 Electrode, 1mg / cm 2 Electrode, 2 mg / cm 2 Electrode, 3 mg / cm 2 Electrode, 4 mg / cm 2 Electrode, 5 mg / cm 2 electrode and the range between any two of the above values.

[0090] In some embodiments, the anode porous substrate layer 32 is a metal mesh or a foamed metal, and the loading amount of the anode catalyst in the anode oxygen evolution electrode 30 is 0.05-20 mg / cm2 Electrode, for example, but not limited to 0.05 mg / cm 2 Electrode, 0.1mg / cm 2 Electrode, 0.5 mg / cm 2 Electrode, 1mg / cm 2 Electrode, 5 mg / cm 2 Electrode, 10 mg / cm 2 Electrode, 15 mg / cm 2 Electrode, 20 mg / cm 2 electrode and the range between any two of the above values.

[0091] In some embodiments, the thickness of the cation exchange membrane 20 is 10 μm to 300 μm, including but not limited to 10 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm and ranges between any two of the above values.

[0092] In some embodiments, the cation exchange membrane 20 is a Nafion membrane. The Nafion membrane may include, but is not limited to, a nafion 117 membrane, a nafion 211 membrane, and a nafion 212 membrane.

[0093] The second aspect of the present application also provides a method for preparing a membrane electrode according to any embodiment of the first aspect, comprising the following steps:

[0094] Step S10, loading the cathode catalyst and the cation regulating substance on the cathode porous substrate layer 12 to obtain the cathode diffusion electrode 10;

[0095] Step S20, loading the anode catalyst on the anode porous substrate layer 32 to obtain the anode oxygen evolution electrode 30; and

[0096] In step S30, the cathode diffusion electrode 10, the cation exchange membrane 20 and the anode oxygen evolution electrode 30 are stacked in sequence.

[0097] In some embodiments, step S10 includes:

[0098] Step S11, mixing the cathode catalyst and the cation regulating substance in a solvent to obtain a mixed coating;

[0099] Step S13 , coating the mixed coating on the cathode porous base layer 12 to form the cathode active layer 14 .

[0100] As a possible implementation, the solvent in step S11 is a mixed solvent of isopropanol and water. Optionally, the volume ratio of isopropanol to water is 4:1 to 1:1.

[0101] As a possible implementation method, the concentration of the cathode catalyst in the mixed coating is 1-100 mg / mL.

[0102] As a possible implementation method, the concentration of the cationic regulating substance in the mixed coating is 1-500 μg / mL.

[0103] In some other embodiments, step S10 includes:

[0104] Step S12, placing the cathode catalyst in a solvent to obtain a cathode catalyst coating;

[0105] Step S14, coating the cathode catalyst coating on the cathode porous substrate layer 12 to form a cathode catalyst layer 141;

[0106] Step S16, placing the cationic regulating substance in a solvent to obtain a cationic regulating substance coating;

[0107] In step S18 , a cation regulating substance coating is applied on the cathode catalyst layer 141 to form a cation regulating substance layer 142 .

[0108] As a possible implementation, the solvent in step S12 is a mixed solvent of isopropanol and water. Optionally, the volume ratio of isopropanol to water is 4:1 to 1:1.

[0109] As a possible implementation, the concentration of the cathode catalyst in the cathode catalyst coating is 1-10 mg / mL.

[0110] As a possible implementation, the solvent in step S16 is a mixed solvent of isopropanol and water. Optionally, the volume ratio of isopropanol to water is 4:1 to 1:1.

[0111] As a possible implementation, the concentration of the cationic regulating substance in the cationic regulating substance coating is 1-500 μg / mL.

[0112] The third aspect of the present application also provides a membrane electrode reactor, comprising the membrane electrode of any embodiment of the first aspect of the present application.

[0113] The membrane electrode reactor also includes other components besides the membrane electrode, such as the cathode flow channel chamber and the anode flow channel chamber. Among them, the components are assembled in the order of cathode flow channel chamber, cathode diffusion electrode, cation exchange membrane, anode oxygen evolution electrode and anode flow channel chamber. It is necessary to ensure that there is good surface contact between adjacent components. The cathode diffusion electrode, cation exchange membrane and anode oxygen evolution electrode need to fit tightly, but still be physically connected.

[0114] In some embodiments, the cathode flow channel chamber is made of graphite or corrosion-resistant metal, including but not limited to one or more of titanium, stainless steel, and Hastelloy. The internal channel width of the cathode flow channel chamber can be 1-12 mm, and the channel depth can be 0.5-5 mm.

[0115] In some embodiments, the anode flow channel chamber is made of graphite or corrosion-resistant metal, including but not limited to one or more of titanium, stainless steel, and Hastelloy. The width of the channel inside the anode flow channel chamber may be 1-12 mm, and the channel depth may be 0.5-5 mm.

[0116] The following are specific embodiments. The purpose is to further explain the present application in detail to help the technical personnel and researchers in the field to further understand the present application. The relevant technical conditions do not constitute any limitation to the present application. Any form of modification made within the scope of the claims of the present application is within the scope of protection of the claims of the present application.

[0117] Unless otherwise specified, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods. Experimental methods without specific conditions specified in the examples are carried out according to conventional conditions, such as those described in literature or books or methods recommended by manufacturers.

[0118] Example 1

[0119] 1 mg of Ni nanocluster-loaded oxidized carbon black catalyst was weighed and mixed with 1.6 μg of Fumasep anion exchange resin, and the solvent was a mixture of 0.6 mL of isopropanol and 0.4 mL of water. The mixture was dispersed in an ultrasonic cleaner to form a uniform coating, and the coating was evenly sprayed on a 1 cm×1 cm GDL carbon paper with a spray pen to form a catalyst loading of 0.2 mg / cm 2 cathode diffusion electrode.

[0120] A 1 cm × 1 cm titanium mesh loaded with IrO2 was used as the anode oxygen evolution electrode. The IrO2 loading was 2 mg / cm 2 .

[0121] The cation exchange membrane used was Nafion 117 membrane with an area of ​​1.2 cm × 1.2 cm.

[0122] The membrane electrode reactor is assembled in the order of cathode flow channel chamber, cathode diffusion electrode, cation exchange membrane, anode oxygen evolution electrode and anode flow channel chamber.

[0123] Example 2

[0124] Weigh 2 mg of oxidized carbon black catalyst and mix it with 100 μg of Piperion anion exchange resin, and the solvent is 0.7 mL of isopropanol and 0.3 mL of water. Disperse it in an ultrasonic cleaner to form a uniform coating, and use a spray pen to evenly spray the coating on a 2 cm×2 cm GDL carbon paper to make a catalyst loading of 0.4 mg / cm 2 cathode diffusion electrode.

[0125] RuO2 loaded on 2 cm×2 cm nickel foam was used as the anode oxygen evolution electrode, and the RuO2 loading amount was 1 mg / cm 2 .

[0126] The cation exchange membrane used was Nafion 211 membrane with an area of ​​2.5 cm × 2.5 cm.

[0127] It is assembled in the order of cathode flow channel chamber, cathode diffusion electrode, cation exchange membrane, anode oxygen evolution electrode and anode flow channel chamber.

[0128] Example 3

[0129] Weigh 1 mg of Co single atom catalyst and 50 μg of quaternary ammonium poly (n-methyl-piperidinyl-co-p-terphenyl) mixed in 0.7 mL of isopropanol and 0.3 mL of water. Disperse it in an ultrasonic cleaner to form a uniform coating, and use a spray pen to evenly spray the coating on a 2 cm × 2 cm carbon paper to make a catalyst loading of 0.2 mg / cm 2 cathode diffusion electrode.

[0130] NiFe hydroxide grown on 1 cm×1 cm nickel foam was used as the anode oxygen evolution electrode with a loading of about 10 mg / cm 2 .

[0131] The cation exchange membrane used was Nafion 117 membrane with an area of ​​2.2 cm × 2.2 cm.

[0132] It is assembled in the order of cathode flow channel chamber, cathode diffusion electrode, cation exchange membrane, anode oxygen evolution electrode and anode flow channel chamber.

[0133] Example 4

[0134] 500 mg of Fe nanocluster-doped carbon nanotubes were weighed and mixed with 1.6 mg of Alkmer anion exchange resin in 8 mL of isopropanol and 2 mL of water. The mixture was dispersed in an ultrasonic cleaner to form a uniform coating, and then the coating was evenly sprayed on a 20 cm × 20 cm GDL commercial carbon cloth using an ultrasonic sprayer to form a catalyst with a loading of 1 mg / cm 2cathode diffusion electrode.

[0135] A 20 cm × 20 cm titanium mesh loaded with IrO2 was used as the anode oxygen evolution electrode, and the IrO2 loading was 2 mg / cm 2 .

[0136] The cation exchange membrane uses Nafion 117 membrane with an area of ​​22.5 cm × 22.5 cm.

[0137] It is assembled in the order of cathode flow channel chamber, cathode diffusion electrode, cation exchange membrane, anode oxygen evolution electrode and anode flow channel chamber.

[0138] Example 5

[0139] 100 mg of oxidized carbon nanotube catalyst was weighed and mixed with 160 μg of poly (fluorenyl-co-terphenyl piperidinium) (PFAP) in 7.8 mL of isopropanol and 2 mL of water. The mixture was dispersed in an ultrasonic cleaner to form a uniform coating, and the coating was evenly sprayed on a 10×10 cm GDL commercial carbon cloth using an ultrasonic sprayer. The carbon was placed on a hot plate at 80 °C to form a catalyst loading of 0.15 mg / cm 2 cathode diffusion electrode.

[0140] FeP / Ni2P loaded on nickel foam was used as the anode oxygen evolution electrode with a loading of 2 mg / cm 2 , the area is 10×10cm.

[0141] The cation exchange membrane used was Nafion212 membrane with an area of ​​12×12 cm.

[0142] The membrane electrolyzer is assembled in the order of cathode flow channel chamber, cathode diffusion electrode, cation exchange membrane, anode oxygen evolution electrode and anode flow channel chamber.

[0143] Example 6

[0144] The preparation method is basically the same as that of Example 3, except that the cathode catalyst is replaced by graphene oxide and the anion exchange resin is replaced by Sustainion.

[0145] Example 7

[0146] The preparation method is basically the same as that of Example 3, except that the cathode catalyst is replaced with graphene oxide, and the cation regulating substance is replaced with 18-crown-6 complexed with sodium ions.

[0147] Example 8

[0148] The preparation method is basically the same as that of Example 3, except that the cathode catalyst is replaced by a carbon material doped with a single Fe atom, and the cation regulating substance is replaced by 15-crown-5 complexed with potassium ions. Example 9

[0149] The preparation method is basically the same as that of Example 3, except that the cathode catalyst is replaced by a carbon material doped with a single Fe atom, and the cation regulating substance is replaced by a quaternary amino poly(aryl perfluoroalkylene).

[0150] Example 10

[0151] The preparation method is basically the same as that of Example 3, except that the cationic regulating substance is replaced with poly (terphenylpiperidinium-trifluoroacetophenone).

[0152] Embodiment 11

[0153] The preparation method is basically the same as that of Example 2, except that the anode oxygen evolution electrode uses IrO2 loaded on carbon paper, and the IrO2 loading amount is 0.5 mg / cm 2 .

[0154] Example 12

[0155] The preparation method is basically the same as that of Example 3, except that the cathode catalyst is replaced by a nano Pt catalyst.

[0156] Embodiments 13 to 15

[0157] The preparation method is basically the same as that in Example 3, except that the mass of the anion exchange resin is different. The specific mass of the anion exchange resin is added according to the mass ratio of the cathode catalyst to the anion exchange resin listed in Table 1, wherein the mass of the Co single atom catalyst is 1 mg.

[0158] Example 16

[0159] The preparation method is basically the same as that of Example 3, except that the cathode catalyst and the anion exchange resin in the cathode diffusion electrode are not mixed, but are made into coatings and coated on carbon paper in layers. The specific preparation of the cathode diffusion electrode is as follows:

[0160] 1 mg of Co single atom catalyst was placed in a solvent, the solvent was 0.7 mL of isopropanol and 0.3 mL of water, it was dispersed in an ultrasonic cleaner to form a uniform coating, and the coating was evenly sprayed on a 2 cm×2 cm carbon paper with a spray pen to obtain a cathode catalyst layer.

[0161] 50 μg of quaternary ammonium poly (n-methyl-piperidinyl-co-p-terphenyl) was placed in a solvent, the solvent was 0.7 mL of isopropanol and 0.3 mL of water, and dispersed in an ultrasonic cleaner to form a uniform coating. The coating was evenly sprayed on the cathode catalyst layer with a spray pen to form a catalyst loading of 0.2 mg / cm 2 cathode diffusion electrode.

[0162] The rest is the same as in Example 3.

[0163] Comparative Example 1

[0164] The preparation method is basically the same as that of Example 1, except that the anion exchange resin in the cathode diffusion electrode is omitted, that is, only the oxidized carbon black catalyst supported by Ni nanoclusters is sprayed on the carbon paper of the cathode diffusion electrode.

[0165] Comparative Example 2

[0166] The preparation method is basically the same as that of Example 1, except that the anion diffusion resin in the cathode diffusion electrode is replaced by the cation exchange resin nafion, that is, a mixed solution of Ni nanocluster-loaded oxidized carbon black catalyst and cation exchange resin is sprayed on the carbon paper of the cathode diffusion electrode.

[0167] The relevant parameters of the membrane electrode reactors in Examples 1 to 15 are listed in Table 1:

[0168] Table 1

[0169]

[0170]

[0171] Application Examples

[0172] Application Examples 1 to 16 and Application Comparative Examples 1 to 2 are as follows Figure 5 The membrane electrode reactors, related pipelines and circuits prepared in the corresponding embodiments and comparative examples are sequentially connected as a reaction system for preparing hydrogen peroxide by oxygen reduction, and oxygen and pure water are mixed into the cathode flow channel chamber through a T-shaped three-way pipeline, wherein the flow rate of oxygen is 25 sccm, wherein the flow rate of pure water in application examples 1 to 3, application examples 6 to 16 and application comparative examples 1 to 2 is 1 mL / min, and the flow rate of pure water in application examples 4 to 5 is 10 mL / min. The cathode pressure is atmospheric pressure. The reactant at the anode is pure water, and its flow rate is 2 mL / min. After the fluid is stably input into the reactor for 10 minutes, the reaction current is set using the electrochemical workstation to allow the reaction to proceed, and a collection bottle is placed at the cathode outlet to collect the reaction liquid product, and the Ce 4+ The hydrogen peroxide produced by titration of ion standard solution is analyzed to determine the concentration of hydrogen peroxide C H2O2, calculate the Faraday efficiency FE, the formula is as follows:

[0173]

[0174] Among them C Ce 4+ 总 is Ce involved in the reaction 4+ The concentration, V Ce 4+ is Ce added during titration 4+ The volume, C Ce 4+ 剩 is the remaining Ce measured by UV spectroscopy after the titration is completed 4+ The concentration, V H2O2 is the volume of the H2O2 reaction product involved in the titration, F is the Faraday constant, which is 96485C / mol, j is the set constant current, and t is the reaction time. Among them, j is 200 mA / cm 2 , t is set to 1 hour.

[0175] The membrane electrode reactor, current density, electrolysis time and volume V of the generated hydrogen peroxide solution corresponding to the application examples 1 to 16 and the application comparative example 1 H2O2 , concentration C H2O2 And the corresponding Faraday efficiency FE is listed in Table 2 below:

[0176] Table 2

[0177]

[0178] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0179] The above-described embodiments only express several implementation methods of the present application, which is convenient for understanding the technical solution of the present application in detail, but it cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent of this application shall be based on the contents of the attached claims, and the description and drawings can be used to explain the contents of the claims.

Claims

1. A membrane electrode for preparing hydrogen peroxide by oxygen reduction, characterized in that: It comprises a cathode diffusion electrode, a cation exchange membrane and an anode oxygen evolution electrode which are stacked, wherein the cation exchange membrane is located between the cathode diffusion electrode and the anode oxygen evolution electrode, and the cathode diffusion electrode, the cation exchange membrane and the anode oxygen evolution electrode are interconnected in a physical manner; The cathode diffusion electrode comprises a cathode porous substrate layer and a cathode active layer, wherein the cathode active layer comprises a cathode catalyst and a cation regulating substance, and the anode oxygen evolution electrode comprises an anode porous substrate layer and an anode active layer, wherein the anode active layer comprises an anode catalyst; The cationic regulating substance includes a cationic polymer and / or a crown ether complexed with a metal ion, and the cationic polymer includes one or more of Fumasep anion exchange resin, Alykmer anion exchange resin, Piperion anion exchange resin, Sustainion anion exchange resin, quaternized polyethyleneimine, cross-linked polydiallyldimethylammonium chloride, quaternary ammonium poly (n-methyl-piperidine-co-p-terphenyl), quaternary amino poly (aryl perfluoroalkylene), poly (terphenyl piperidinium-trifluoroacetophenone), poly (diphenyl-co-terphenyl piperidinium) (PDTP), branched poly (terphenyl piperidinium) and poly (fluorenyl-co-terphenyl piperidinium) (PFAP).

2. The membrane electrode according to claim 1, characterized in that: The cathode catalyst is one or more of an oxidized carbon material, a metal single atom-doped carbon material, and a metal nanocluster-doped carbon material.

3. The membrane electrode according to claim 2, characterized in that: The metal ion complexed crown ether includes one or more of 18-crown-6 complexed with sodium ions, 15-crown-5 complexed with potassium ions, and 12-crown-4 complexed with sodium ions.

4. The membrane electrode according to claim 2, characterized in that: The oxidized carbon material comprises one or more of oxidized graphene, oxidized carbon nanotubes and oxidized carbon black; and / or, The metal single atom doped carbon material includes Co or Fe single atom doped carbon material; and / or, The metal nanocluster doped carbon material includes one or more of a Ni nanocluster doped carbon material, a Cu nanocluster doped carbon material and a Fe nanocluster doped carbon material.

5. The membrane electrode according to claim 1, characterized in that: The loading amount of the cathode catalyst in the cathode diffusion electrode is 0.05-5 mg / cm 2 The cathode diffusion electrode and / or the cathode diffusion electrode have a cation regulating substance loading of 1 to 500 μg / cm 2 electrode.

6. The membrane electrode according to any one of claims 1 to 5, characterized in that: The mass ratio of the cathode catalyst to the cation regulating substance in the cathode diffusion electrode is 1:(0.0016-0.06).

7. The membrane electrode according to claim 1, characterized in that: The anode catalyst includes one or more of iridium oxide, ruthenium oxide, rhodium oxide, iron oxide, cobalt oxide, nickel oxide, perovskite oxide, NiFe oxide, NiFe hydroxide, iron sulfide, cobalt sulfide, nickel sulfide, copper sulfide, manganese sulfide, Ni phosphide and Fe phosphide.

8. The membrane electrode according to claim 1 or 7, characterized in that: The loading amount of the anode catalyst in the anode oxygen evolution electrode is 0.05-20 mg / cm 2 electrode.

9. The membrane electrode according to claim 1, characterized in that: The cathode active layer includes a cathode catalyst layer and a cation regulating material layer. The cathode catalyst layer is arranged close to the cathode porous substrate layer, and the cation regulating material layer is arranged far away from the cathode porous substrate layer.

10. The membrane electrode according to claim 1, characterized in that: The porosity of the cathode porous substrate layer is 20% to 80%; And / or, the porosity of the anode porous substrate layer is 20% to 80%.

11. The membrane electrode according to claim 10, characterized in that: One or more of the following conditions are met: (1) The cathode porous substrate layer is carbon paper or carbon cloth; (2) The anode porous substrate layer is carbon paper, carbon cloth, metal mesh or foam metal.

12. The membrane electrode according to claim 1, characterized in that: The cation exchange membrane has a thickness of 10 μm to 300 μm.

13. The membrane electrode according to claim 12, characterized in that: The cation exchange membrane is a Nafion membrane.

14. A method for preparing a membrane electrode according to any one of claims 1 to 13, characterized in that: The following steps are involved: Step S10, loading the cathode catalyst and the cation regulating substance on the cathode porous substrate layer to obtain the cathode diffusion electrode; Step S20, loading the anode catalyst on the anode porous substrate layer to obtain the anode oxygen evolution electrode; as well as Step S30, stacking the cathode diffusion electrode, the cation exchange membrane and the anode oxygen evolution electrode in sequence.

15. The method for preparing a membrane electrode according to claim 14, characterized in that: Step S10 includes: Step S11, mixing the cathode catalyst and the cation regulating substance in a solvent to obtain a mixed coating; Step S13, coating the mixed coating on the cathode porous substrate layer.

16. The method for preparing a membrane electrode according to claim 14, characterized in that: Step S10 includes: Step S12, placing the cathode catalyst in a solvent to obtain a cathode catalyst coating; Step S14, coating the cathode catalyst coating on the surface of the cathode porous substrate layer to form a cathode catalyst layer; Step S16, placing the cationic regulating substance in a solvent to obtain a cationic regulating substance coating; Step S18, coating the cation regulating substance coating on the surface of the cathode catalyst layer to form a cation regulating substance layer.

17. A membrane electrode reactor, characterized in that: A membrane electrode comprising the membrane electrode according to any one of claims 1 to 13.

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