阅读说明：本技术 一种疏水高分子膜负载蒸镀金属气体扩散电极、制备方法及其应用 (Hydrophobic polymer film loaded metal vapor deposition gas diffusion electrode, preparation method and application thereof ) 是由 杨化桂 曹琳 刘鹏飞 程军 吴雪枫 毛芳欣 袁海洋 杨晓华 于 2020-12-17 设计创作，主要内容包括：本发明涉及一种具有高效电催化二氧化碳还原生成多碳产物的疏水高分子膜负载蒸镀金属气体扩散电极的制备方法及应用,所述气体扩散电极包括疏水高分子膜以及负载于所述疏水高分子膜表面的金属材料。所述疏水高分子膜包括但不限于聚四氟乙烯,孔径为0.1-1μm；所述疏水高分子膜中含有的起支撑作用的材料包括但不限于聚丙烯、聚对苯二甲酸乙二醇酯。所述金属材料包括但不限于铜、银、金、锌。本发明还公开了上述电极的制备方法和电催化用途。上述电极材料可应用于电化学还原二氧化碳,并对多碳产物具有较高的选择性,在推动电催化材料进一步实现器件化上有重要的作用,在环境科学和新能源领域有着非常广阔的应用前景。(The invention relates to a preparation method and application of a hydrophobic polymer film loaded evaporated metal gas diffusion electrode capable of efficiently electrocatalysis carbon dioxide reduction to generate a multi-carbon product. The hydrophobic polymer membrane comprises but is not limited to polytetrafluoroethylene, and the pore diameter is 0.1-1 mu m; the material contained in the hydrophobic polymer film for supporting includes, but is not limited to, polypropylene and polyethylene terephthalate. The metal material includes, but is not limited to, copper, silver, gold, zinc. The invention also discloses a preparation method and electrocatalysis application of the electrode. The electrode material can be applied to electrochemical reduction of carbon dioxide, has high selectivity on multi-carbon products, plays an important role in promoting the electrocatalytic material to further realize device formation, and has very wide application prospects in the fields of environmental science and new energy.)

1. A preparation method of a gas diffusion electrode of a hydrophobic polymer film loaded evaporated metal is characterized by comprising the following steps:

the surface of the hydrophobic polymer film is purged by nitrogen or argon; and evaporating and plating a layer of metal with the thickness of 1-1000nm on the hydrophobic polymer film.

2. The method for preparing a hydrophobic polymer film supported evaporated metal gas diffusion electrode according to claim 1, wherein the hydrophobic polymer film is evaporated with a layer of metal with a thickness of 100-900nm, preferably with a thickness of 300-800 nm; more preferably 500-700nm thick.

3. The method for preparing the hydrophobic polymer film supported evaporated metal gas diffusion electrode according to claim 2, wherein the metal with the thickness of 600nm is evaporated on the hydrophobic polymer film.

4. The method for preparing the hydrophobic polymer film supported evaporated metal gas diffusion electrode according to claim 1, wherein the pore diameter of the hydrophobic polymer film is 0.1-1 μm; the pore size is preferably 0.3 to 0.8. mu.m, more preferably 0.4 to 0.6. mu.m, and most preferably 0.45. mu.m.

5. The method for preparing a gas diffusion electrode with a hydrophobic polymer film supporting evaporated metal according to claim 1, wherein the hydrophobic polymer film is polytetrafluoroethylene.

6. The method for preparing the gas diffusion electrode on which the hydrophobic polymer film is coated with the evaporated metal according to claim 1, wherein a support material is further added to the hydrophobic polymer film, and the support material is polypropylene or polyethylene terephthalate.

7. The method for preparing the gas diffusion electrode with the metal evaporated on the hydrophobic polymer film according to claim 1, wherein the metal material is copper, silver, gold or zinc.

8. The method for preparing a gas diffusion electrode comprising a hydrophobic polymer film-supported evaporated metal as claimed in claim 1, wherein the degree of vacuum during evaporation is 6X 10^-4-1×10^-5Pa, evaporation rate of

9. A hydrophobic polymer film-supported evaporated metal gas diffusion electrode obtained by the production method according to any one of claims 1 to 8.

10. The hydrophobic polymeric membrane supported evaporated metal gas diffusion electrode according to claim 9, applied to the field of electrochemical reduction of carbon dioxide.

Technical Field

The invention relates to a hydrophobic polymer film loaded evaporated metal gas diffusion electrode capable of efficiently electro-catalyzing carbon dioxide reduction to generate a multi-carbon product, and a preparation method and application thereof. The material is used as an electrocatalytic material and has higher performance of electrocatalysis of carbon dioxide to generate multi-carbon products (ethylene, ethanol, acetic acid and the like). The material is expected to promote the electrocatalytic material to further realize device and industrialization when being used for a cathode electrode for electrocatalytic carbon dioxide reduction in the future, and has very important prospects in the fields of environmental science and new energy.

Background

Fossil fuels are not only used as portable and schedulable energy carriers, but also are sources of chemical raw materials and fertilizers. As society develops, human dependence on fossil fuels increases, which leads to a continuous consumption of energy worldwide and aggravation of environmental and climate problems. Electrochemical carbon dioxide reduction (CO)₂ reduction reaction,CO₂RR) can convert carbon dioxide into valuable fuels and feedstocks, providing an attractive solution to the above problem, helping to store intermittent renewable electricity and shutting down artificial carbon cycles.

Study ofSilver, gold and zinc can be used for catalyzing CO₂Electro-reduction to CO. Ethylene (C) in contrast to the single carbon product₂H₄) Ethanol (C)₂H₅OH) and the like have higher energy density and market value. The conversion of carbon dioxide to ethylene is a 12-electron reduction process, and among the developed electrocatalyst materials, copper-based catalysts have higher selectivity at high current density. However, despite current advances in catalyst and reactor design, CO₂The energy efficiency of the RR is still not sufficient for commercial needs. Improving the CO of multi-carbon products such as ethylene₂Research on RR selectivity and yield is crucial to the marketability of this technology. The chemical microstructure of the surface of the copper catalyst plays an important role in determining a reaction path, increasing the surface area, promoting a directional conversion reaction and other strategies. In order to improve the selectivity of the product and reduce the reaction energy barrier, schemes of regulating the oxidation state of copper, exposing a high-refractive-index facet, introducing a strain effect, reconstructing a surface structure and the like have been explored. However, integrated control and characterization of surface chemistry microstructures remains challenging. In addition, the catalyst loaded on the common carbon-supported gas diffusion electrode is bonded with the gas diffusion electrode through an adhesive, so that the gas diffusion layer is damaged and falls off in the large-current catalysis process, and the local voltage distribution of the catalyst in the working state is not uniform due to the loose combination and the non-uniform distribution of the catalyst and the gas diffusion layer, and the gas diffusion layer has unstable electrochemical performance and poor mechanical performance.

In order to solve the problems, the invention utilizes a simple evaporation process to comprehensively regulate and control the surface appearance of metal, and metal materials are evaporated on the hydrophobic polymer membrane, so that the bonding force between the metal and the gas diffusion layer is enhanced, and meanwhile, the stability of the polymer membrane can ensure that the formed electrode can keep CO under high current₂High selectivity of RR multi-carbon product.

Disclosure of Invention

The invention aims to provide a hydrophobic polymer film loaded evaporated metal gas diffusion electrode capable of efficiently electro-catalyzing carbon dioxide reduction to generate a multi-carbon product, a preparation method and application thereof, wherein the preparation method is simple and has high repeatability. The prepared gas diffusion electrode has higher catalytic carbon dioxide reduction reaction activity and multi-carbon product selectivity.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a gas diffusion electrode of a hydrophobic polymer film loaded evaporated metal is characterized by comprising the following steps:

the surface of the hydrophobic polymer film is purged by nitrogen or argon; and evaporating and plating a layer of metal with the thickness of 1-1000nm on the hydrophobic polymer film.

Further, the hydrophobic polymer film is coated with a layer of metal with the thickness of 100-900nm, preferably with the thickness of 300-800nm by evaporation; more preferably 500-700nm thick.

Further, a layer of metal with the thickness of 600nm is optimally evaporated on the hydrophobic polymer film.

Further, the hydrophobic polymer membrane includes, but is not limited to, polytetrafluoroethylene having a pore size of 0.1 to 1 μm, preferably 0.3 to 0.8 μm, more preferably 0.4 to 0.6 μm, and most preferably 0.45 μm; the support material contained in the hydrophobic polymer film includes, but is not limited to, polypropylene or polyethylene terephthalate.

Further, the metal material includes, but is not limited to, copper, silver, gold, or zinc.

Further, the degree of vacuum at the time of vapor deposition was 6X 10^-4-1×10^-5Pa, evaporation rate of

The invention also provides a hydrophobic polymer film loaded evaporated metal gas diffusion electrode material prepared by the preparation method.

The invention also aims to provide the application of the hydrophobic polymer film supported evaporated metal gas diffusion electrode in the field of electrochemical reduction of carbon dioxide.

The invention has the beneficial effects that:

(1) the metal is loaded on the hydrophobic polymer film by adopting a simple evaporation process, the metal and the hydrophobic polymer film are tightly combined, the operation is simple and convenient, and the repeatability is good;

(2) the types of the selectable metals are various, and the corresponding metals can be selected for evaporation according to different target products;

(3) in the preparation process, all reagents are commercial products and do not need further treatment;

(4) the synthesis method is simple and easy to apply, can be directly used as a cathode electrode in an electrocatalysis device, does not need further treatment, and can promote the electrocatalysis to develop towards a large-scale and industrialized direction.

Drawings

FIG. 1 is a CO gas diffusion electrode of hydrophobic polymer membrane supported evaporated metal prepared in example 1₂Scanning electron micrographs before and after RR reaction;

FIG. 2 is a scanning electron microscope image of the cross section of the gas diffusion electrode of the hydrophobic polymer film-supported evaporated metal prepared in example 1;

FIG. 3 is a CO gas diffusion electrode of hydrophobic polymer film supported evaporated metal prepared in example 1₂X-ray diffraction patterns of the RR before and after reaction and the hydrophobic polymer film;

FIG. 4 is a CO gas diffusion electrode of hydrophobic polymer film supported evaporated metal prepared in example 1₂Infrared spectrograms before and after RR reaction;

FIG. 5 shows CO of the gas diffusion electrode of hydrophobic polymer membrane supporting evaporated metal prepared in example 1₂A graph of the RR product Faraday efficiency versus current density;

FIG. 6 shows the gas diffusion electrode of the hydrophobic polymer film supported evaporated metal prepared in example 1 at a constant current density of 200mA cm^-2CO of₂RR gas product distribution stability test chart.

Detailed Description

The following detailed description of the present invention will be made with reference to the accompanying drawings and examples, but the scope of the present invention should not be limited thereby.

The "ranges" disclosed herein are in the form of lower and upper limits. There may be one or more lower limits, and one or more upper limits, respectively. The given range is defined by the selection of a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges that can be defined in this manner are inclusive and combinable, i.e., any lower limit can be combined with any upper limit to form a range. For example, ranges of 60-120 and 80-110 are listed for particular parameters, with the understanding that ranges of 60-110 and 80-120 are also contemplated. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum ranges 3, 4, and 5 are listed, the following ranges are all contemplated: 1-2, 1-4, 1-5, 2-3, 2-4 and 2-5.

In the present invention, unless otherwise stated, the numerical range "a-b" represents a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0 to 5" indicates that all real numbers between "0 to 5" have been listed herein, and "0 to 5" is only a shorthand representation of the combination of these numbers.

In the present invention, all embodiments and preferred embodiments mentioned herein may be combined with each other to form a new technical solution, if not specifically stated.

In the present invention, all the technical features mentioned herein and preferred features may be combined with each other to form new technical solutions, if not specifically mentioned.

The preferred embodiments of the present invention will be described in detail with reference to the following examples, but it should be understood that those skilled in the art can reasonably change, modify and combine the examples to obtain new embodiments without departing from the scope defined by the claims, and that the new embodiments obtained by changing, modifying and combining the examples are also included in the protection scope of the present invention.

Example 1

Step one, preparing a gas diffusion electrode of a hydrophobic polymer film loaded evaporated metal

Using nitrogen to make hydrophobic polymer membrane (pore diameter is 0.45 μm, main body material: polytetrafluoroethylene, support)Supporting materials: polyethylene terephthalate) was purged and then placed in the cavity of an evaporation instrument (OMV FS 300-S6). The copper target (purity: 99.9999%) is put into a tungsten boat, and the hatch door is closed. After the vacuum degree is reduced to 8.6 multiplied by 10^-5Heating is started when Pa is reached, and the evaporation rate is controlled to beUntil the copper layer thickness reaches 600 nm. And obtaining the hydrophobic polymer film loaded evaporated copper electrode.

Fig. 1 is scanning electron micrographs of the prepared hydrophobic polymer film loaded copper-evaporated electrode before (a, b) and after (c, d) the reaction, and it can be seen that copper is uniformly distributed in a nanoparticle state along the fibers of the hydrophobic polymer film, and the change before and after the reaction is not obvious.

FIG. 2 is a scanning electron microscope image of the cross section of the gas diffusion electrode of the hydrophobic polymer film-supported deposited metal prepared in example 1.

FIG. 3 shows the prepared hydrophobic polymer film loaded evaporated metal gas diffusion electrode CO₂Before and after RR reaction and the X-ray diffraction pattern of the hydrophobic polymer film, it can be seen that the evaporated copper mainly exposes Cu (111) and Cu (200) crystal planes.

FIG. 4 is a CO gas diffusion electrode of hydrophobic polymer film supported evaporated metal prepared in example 1₂Infrared spectra before and after RR reaction.

Step two, performance characterization test

The carbon dioxide reduction reaction of the metal gas diffusion electrode carried by the hydrophobic polymer film is carried out in an electrochemical flow cell with the square centimeter of 0.5. The flow cell is composed of three compartments: a gas chamber, a catholyte chamber, and an anolyte chamber. The gas chamber and the cathode chamber are separated by a hydrophobic polymer film loaded copper-evaporated electrode. The cathode chamber and the anode chamber are separated by an anion exchange membrane (Fumasep FAB-PK-130). The hydrophobic polymer film loaded evaporated copper electrode, Ag/AgCl electrode (3.5M KCl as filling solution) and foamed nickel are respectively used as a working electrode, a reference electrode and a counter electrode. The flow cell was connected to an electrochemical workstation (CHI 660E). 1M KOH was used as the cathode and anode electrolytes. CO 2₂The flow rate of the gas was fixed at 20sccAnd m is selected. The gas products were separated by gas chromatography (GC 2060) and detected by a thermal conductivity detector and a flame ionization detector. High purity argon (99.99%) was used as the carrier. Using dimethyl sulfoxide as internal standard by¹The liquid product was quantified by H-NMR (Varian 700M spectrometer). The Faradaic Efficiency (FE) of the gaseous product is calculated according to the following formula:

wherein i_xIs the partial current of the product x, i_totIs the total current, n_xDenotes the number of electrons transferred to give 1mol of product x, v_gasIs CO₂Flow rate (sccm), c_xDenotes the concentration (ppm) of the product x detected by gas chromatography, F is the Faraday constant (96485C/mol), V_mIs 24.5L/mol at room temperature (298.15K) in terms of unit molar volume.

FIG. 5 shows CO of the gas diffusion electrode of hydrophobic polymer membrane supporting evaporated metal prepared in example 1₂Graph of faradaic efficiency versus current density for RR gas phase products. Therefore, the hydrophobic polymer film loaded evaporated copper electrode prepared by the evaporation method has excellent CO₂RR activity, the product is mainly ethylene and ethanol, and the generation of hydrogen evolution reaction can be greatly inhibited.

FIG. 6 shows the gas diffusion electrode of the hydrophobic polymer film supported evaporated metal prepared in example 1 at a constant current density of 200mA cm^-2CO of₂RR gas product distribution stability test chart. It can be seen that the selectivity of the electrode to ethylene was almost unchanged during the test.