Electrode and Preparation Method and Use Thereof

This patent application claims the benefit and priority of Chinese Patent Application No. 2024108055716 filed with the China National Intellectual Property Administration on Jun. 21, 2024, the disclosure of which is incorporated by reference herein in its entirety as part of the present application.

The present disclosure belongs to the technical field of electrocatalysis, and specifically relates to an electrode and a preparation method and use thereof.

Hydrogen peroxide (HO), as an important chemical raw material, is widely used in industries such as chemical industry (organic synthesis, pulp or textile bleaching, or the like), wastewater treatment, energy conversion, and medical disinfection. The traditional anthraquinone process for preparing HOhas disadvantages such as high energy consumption, large organic solvent loss, and potential safety hazards in transportation and storage. Electrocatalytic oxygen reduction reaction process for preparing HOis based on a two-electron (2eORR) oxygen reduction reaction at a cathode. Compared with the traditional anthraquinone process, the electrocatalytic oxygen reduction reaction process has many advantages, such as an eco-friendly and safe synthesis route, no generation of organic by-products, possible in-situ production, and easy operations. Therefore, the electrocatalytic oxygen reduction reaction process is a desirable process for industrial preparation of HO.

In the Chinese patent CN116081579A, Se defect-rich cubic-phase cobalt selenide (c-CoSe) is adopted as a cathode material. In the Chinese patent CN115786962A, a metal/non-metal-co-doped amorphous carbon material is prepared with molybdenum and fluorine and then used to synthesize a cathode material, and the synthesized cathode material could promote the electrocatalytic oxygen reduction for preparing HOto some extent. However, the industrial electrochemical preparation of HOis usually conducted in a membrane electrolyzer, where a cathode chamber is separated from an anode chamber through an ion exchange membrane and Ois reduced into HOby electrochemical means (O+2H+2e→HO) in the cathode chamber. In such a system, it is necessary to use an ion exchange membrane because HOis very easily oxidized into O(HO→O+2H+2e) at an anode. However, the ion exchange membranes are inherently expensive, and are susceptible to microbial contamination or chemical attack in a complicated water environment, resulting in a high cost for regular replacement of the ion exchange membranes in practical applications.

Although a membrane-free electrolyzer (such as the electro-Fenton system) can be adopted for the electrocatalytic production of HOin some applications, due to the fact that a cathode and an anode are arranged in the same chamber, many side reactions occur to cause a very low HOyield, such as HOoxidation (HO→O+H+2e) at an anode, HOreduction (HO+2H+2e→HO) at a cathode, and HOdecomposition (2HO→2HO+O). Therefore, how to maintain a high HOconcentration generated in a system while avoiding the use of an ion exchange membrane in a membrane-free electrolyzer is very important for the large-scale application of the technology to prepare HOthrough electrocatalytic oxygen reduction.

In order to solve the problems in the prior art, the present disclosure provides an electrode and a preparation method and use thereof. The electrode provided by the present disclosure could achieve the preparation of high-concentration HOin a membrane-free electrolyzer.

To achieve the above objects, the present disclosure provides the following technical solutions.

The present disclosure provides an electrode, including a modified anode and a modified cathode, where the modified anode includes an anode and a first hydrophobic porous layer coated on a surface of the anode, and the modified cathode includes a current collector, a carbon catalysis layer attached to a surface of the current collector, and a second hydrophobic porous layer attached to a surface of the carbon catalysis layer.

A material of the first hydrophobic porous layer and a material of the second hydrophobic porous layer are independently one or more selected from the group consisting of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polypropylene (PP), polyethylene (PE), and polysulfone (PSF).

In some embodiments, raw materials for preparing the carbon catalysis layer include a binder and a carbon material, the carbon material including one or more selected from the group consisting of carbon black, activated carbon, and graphene and the binder including one or more selected from the group consisting of a PTFE binder, a PVDF binder, a PAN binder, a PMMA binder, a PP binder, a PE binder, and a PSF binder.

In some embodiments, a mass ratio of the carbon material to the binder is in a range of 1-5:1.

In some embodiments, the first hydrophobic porous layer has a thickness independently of 8 μm to 20 μm and a pore size of 0.1 μm to 10 μm, and the second hydrophobic porous layer has a thickness independently of 12 μm.

In some embodiments, the carbon catalysis layer has a thickness of 0.01 mm to 1 mm.

The present disclosure also provides a method for preparing the electrode described above, including preparing the modified anode by a process including subjecting a solution of a first hydrophobic polymer material to first dispersion and stabilization in a first organic solvent to obtain a first diluted hydrophobic polymer solution, loading the first diluted hydrophobic polymer solution to the surface of the anode to obtain a first hydrophobic porous layer-loaded anode, where the loading is conducted under first heating to remove the first organic solvent; and subjecting the first hydrophobic porous layer-loaded anode to first heat treatment to obtain the modified anode.

The method further includes preparing the modified cathode by a process including subjecting the binder and the carbon material to second dispersion and stabilization in a second organic solvent to obtain a carbon catalysis mixture, loading the carbon catalysis mixture to the surface of the current collector to obtain a carbon catalysis layer-loaded cathode, where the loading is conducted under second heating to remove the second organic solvent, subjecting the carbon catalysis layer-loaded cathode to second heat treatment to obtain a carbon material air cathode; and subjecting a solution of a second hydrophobic polymer material to third dispersion and stabilization in a third organic solvent to obtain a second diluted hydrophobic polymer solution; and loading the second diluted hydrophobic polymer solution to a surface of the carbon material air cathode to obtain the modified cathode, where the loading is conducted under third heating to remove the third organic solvent.

In some embodiments, the first organic solvent, the second organic solvent, and the third organic solvent are independently one or more selected from the group consisting of absolute ethanol, dimethylacetamide (DMAc), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and sulfolane (MSDS).

In some embodiments, the first heat treatment is conducted at a temperature of 100° C. to 400° C. for 10 min to 60 min.

In some embodiments, the second heat treatment is conducted at a temperature of 60° C. to 400° C. for 10 min to 60 min.

The present disclosure also provides use of the electrode described above or the electrode prepared by the method described above in synthesis of HOby an in-situ electrocatalytic oxygen reduction reaction in a membrane-free electrolyzer.

The present disclosure provides an electrode, including a modified anode or a modified cathode, where the modified anode includes an anode and a first hydrophobic porous layer coated on a surface of the anode; the modified cathode includes a current collector, a carbon catalysis layer attached to a surface of the current collector, and a second hydrophobic porous layer attached to a surface of the carbon catalysis layer; and a material of the first hydrophobic porous layer and a material of the second hydrophobic porous layer are independently one or more selected from the group consisting of PTFE, PVDF, PAN, PMMA, PP, PE, and PSF. In the present disclosure, a uniform hydrophobic porous layer is formed with a hydrophobic polymer material on a surface of the electrode, which reduces the anodic oxidation of HOinto oxygen and the further reduction of HOinto water at a cathode without affecting the cathodic oxygen reduction to produce HO. Therefore, compared with an ion exchange membrane-containing electrolyzer adopted in the traditional electrochemical preparation of the HO, the present disclosure could reduce use of an ion exchange membrane in the electrochemical preparation of the HO, does not require additional reagents, and could reduce the reaction cost and the system energy consumption while allowing the preparation of high-concentration HO. In addition, in the present disclosure, because the uniform hydrophobic porous layer is formed on the surface of the electrode, a stable solid/liquid/gas three-phase interface could be formed through hydrophobicity and a uniform hydrophobic porous structure on the surface of the electrode, and bubbles generated at an electrode interface after application of a voltage, which could reduce the occurrence of side reactions at the electrode.

The present disclosure provides an electrode, including a modified anode and a modified cathode, where the modified anode includes an anode and a first hydrophobic porous layer coated on a surface of the anode; the modified cathode includes a current collector, a carbon catalysis layer attached to a surface of the current collector, and a second hydrophobic porous layer attached to a surface of the carbon catalysis layer; and

In the present disclosure, an electrode includes a modified anode or a modified cathode.

In the present disclosure, the modified anode includes an anode and a first hydrophobic porous layer coated on a surface of the anode.

In some embodiments of the present disclosure, the anode is a commercially-available product, and specifically, the anode is one selected from the group consisting of a coated titanium anode (DSA), a fluorine-doped tin oxide conductive glass (FTO), and a graphite plate.

In some embodiments of the present disclosure, a material of the first hydrophobic porous layer is one or more selected from the group consisting of PTFE, PVDF, PAN, PMMA, PP, PE, and PSF, and preferably the PTFE. In some embodiments of the present disclosure, the first hydrophobic porous layer has a thickness of 8 μm to 20 μm, and preferably 12 μm to 16 μm. In some embodiments of the present disclosure, the first hydrophobic porous layer has a pore size of 0.1 μm to 10 μm, and preferably 0.5 μm to 6 μm.

shows a schematic structural diagram of the modified anode provided by the present disclosure. It can be seen fromthat the modified anode includes the anode and the first hydrophobic porous layer coated on the surface of the anode.

In the present disclosure, the modified cathode includes a current collector, a carbon catalysis layer attached to a surface of the current collector, and a second hydrophobic porous layer attached to a surface of the carbon catalysis layer.

In some embodiments of the present disclosure, the current collector includes one selected from the group consisting of a carbon paper, a carbon felt, and a carbon cloth, and is preferably the carbon paper.

In some embodiments of the present disclosure, raw materials for preparing the carbon catalysis layer include a binder and a carbon material. In some embodiments of the present disclosure, the carbon material includes one or more selected from the group consisting of carbon black, activated carbon, and graphene, and is preferably the carbon black. In some embodiments of the present disclosure, the binder includes one or more selected from the group consisting of a PTFE binder, a PVDF binder, a PAN binder, a PMMA binder, a PP binder, a PE binder, and a PSF binder, and is preferably a PTFE binder.

In some embodiments of the present disclosure, the carbon catalysis layer has a thickness of 0.01 mm to 1 mm, and preferably 0.08 mm to 0.1 mm.

In some embodiments of the present disclosure, a material of the second hydrophobic porous layer is one or more selected from the group consisting of PTFE, PVDF, PAN, PMMA, PP, PE, and PSF, and preferably the PTFE.

In some embodiments of the present disclosure, the second hydrophobic porous layer has a thickness of 12 μm.

shows a schematic structural diagram of the modified cathode provided by the present disclosure. It can be seen fromthat the modified cathode includes the current collector, the carbon catalysis layer attached to the surface of the current collector, and the second hydrophobic porous layer attached to the surface of the carbon catalysis layer.

The present disclosure also provides a method for preparing the electrode described above, including: preparing the modified anode and preparing the modified cathode.

In the present disclosure, preparing the modified anode includes the steps of:

In the present disclosure, a solution of a first hydrophobic polymer material is subjected to first dispersion and stabilization in a first organic solvent to obtain a first diluted hydrophobic polymer solution.

In some embodiments of the present disclosure, the first organic solvent includes one or more selected from the group consisting of absolute ethanol, DMAc, DME, DMSO, and MSDS, and is preferably the absolute ethanol. In some embodiments of the present disclosure, the solution of the first hydrophobic polymer material has a mass concentration of 0.05% to 0.2%, and preferably 0.1% to 0.15%.

In some embodiments of the present disclosure, the first dispersion and stabilization is conducted for 5 min to 60 min, and preferably 10 min to 40 min.

In the present disclosure, after the first diluted hydrophobic polymer solution is obtained, the first diluted hydrophobic polymer solution is loaded to the surface of the anode to obtain a first hydrophobic porous layer-loaded anode, where loading is conducted under first heating to remove the first organic solvent.

In some embodiments of the present disclosure, a way for the loading includes coating or impregnation, and a way for the coating is spray-coating, spin-coating, or roll-coating

In some embodiments of the present disclosure, the first heating is conducted as follows: during the loading, a heating plate is placed below the anode to evaporate the first organic solvent, where a temperature of the heating plate is in a range of 50° C. to 100° C., and preferably in a range of 60° C. to 80° C.

In the present disclosure, after the first hydrophobic porous layer-loaded anode is obtained, the first hydrophobic porous layer-loaded anode is subjected to first heat treatment to obtain the modified anode.

In some embodiments of the present disclosure, the first heat treatment is conducted at a temperature of 100° C. to 400° C., and preferably 200° C. to 350° C. In some embodiments of the present disclosure, the first heat treatment is conducted for 10 min to 60 min, and preferably 20 min to 50 min.

In the present disclosure, preparing the modified cathode includes the steps of:

In the present disclosure, the binder and the carbon material are subjected to second dispersion and stabilization in a second organic solvent to obtain a carbon catalysis mixture.

In some embodiments of the present disclosure, the second organic solvent and a time of the second dispersion and stabilization are the same as the first organic solvent and the time of the first dispersion and stabilization, which are not repeated here.

In the present disclosure, after the carbon catalysis mixture is obtained, the carbon catalysis mixture is loaded to the surface of the current collector to obtain a carbon catalysis layer-loaded cathode, where loading is conducted under second heating to remove the second organic solvent.

In the present disclosure, a way for the loading is the same as the way for the loading to prepare the modified anode, which is not be repeated here. In some embodiments of the present disclosure, the second heating is conducted as follows: during the loading, a heating plate is placed below the current collector for heating, where a temperature of the heating plate is 60° C. to 100° C., and preferably 60° C. to 80° C.

In the present disclosure, after the carbon catalysis layer-loaded cathode is obtained, the carbon catalysis layer-loaded cathode is subjected to second heat treatment to obtain a carbon material air cathode.

In some embodiments of the present disclosure, the second heat treatment is conducted at a temperature of 60° C. to 400° C., and preferably 200° C. to 350° C. In some embodiments of the present disclosure, the second heat treatment is conducted for 10 min to 60 min, and preferably 20 min to 50 min.