阅读说明：本技术 一种卤素掺杂碱式氯化铜化合物及其制备方法和应用 (Halogen-doped basic copper chloride compound and preparation method and application thereof ) 是由 彭慧胜 张波 白海鹏 于 2020-06-08 设计创作，主要内容包括：本发明属于电催化二氧化碳还原技术领域,具体为一种用于电催化二氧化碳还原反应的催化剂前驱体卤素掺杂碱式氯化铜化合物及其制备方法和应用。本发明卤素掺杂碱式氯化铜化合物由溶胶凝胶法制备得到,卤素为溴或碘,含量为1%-20%。本发明制备的卤素掺杂碱式氯化铜可作为电催化二氧化碳还原反应催化剂前驱体用于制备电催化二氧化碳还原反应催化剂电极；其中,卤素掺杂可促进催化剂前驱体在催化剂活化过程中特定表面微形貌与结构的形成,并调控催化剂结构,进而调控催化反应路径,改变催化剂选择性。本发明溶胶凝胶法工艺简单,能实现高选择性电催化二氧化碳还原生成甲烷或乙烯,在电催化二氧化碳还原领域具有良好的应用前景。(The invention belongs to the technical field of electrocatalytic carbon dioxide reduction, and particularly relates to a catalyst precursor halogen-doped basic copper chloride compound for electrocatalytic carbon dioxide reduction reaction, and a preparation method and application thereof. The halogen-doped basic copper chloride compound is prepared by a sol-gel method, wherein the halogen is bromine or iodine, and the content of the halogen is 1-20%. The halogen-doped basic copper chloride prepared by the invention can be used as a precursor of a catalyst for electrocatalytic carbon dioxide reduction reaction to prepare an electrode of the catalyst for electrocatalytic carbon dioxide reduction reaction; the halogen doping can promote the formation of the specific surface micro-morphology and structure of the catalyst precursor in the catalyst activation process, and regulate and control the catalyst structure, so as to regulate and control the catalytic reaction path and change the catalyst selectivity. The sol-gel method has simple process, can realize the high-selectivity electrocatalysis of carbon dioxide to reduce to generate methane or ethylene, and has good application prospect in the field of electrocatalysis of carbon dioxide reduction.)

1. A catalyst precursor halogen-doped basic copper chloride compound for electrocatalytic carbon dioxide reduction reaction is characterized by being prepared by a sol-gel method, wherein halogen is one of bromine or iodine and accounts for 1% -20%.

2. A process for the preparation of a halogen-doped basic copper chloride compound according to claim 1, wherein propylene oxide-assisted hydrolysis is employed; the method comprises the following specific steps:

first, ethanol and isopropanol were mixed in a vessel, and CuCl was added₂And KBr or KI, stirring until the KBr or the KI is dissolved; adding deionized water into the solution, and then slowly dropwise adding propylene oxide; standing for 12-36 hours, adding acetone into the container, transferring the container into a centrifuge tube, and continuously standing for 80-120 hours; and finally, centrifuging for 5-8 times by using a high-speed centrifuge and acetone as a solvent, drying the product, grinding and collecting to obtain a catalyst precursor bromine or iodine doped basic copper chloride.

3. Use of a halogen-doped basic copper chloride compound as defined in claim 1 as a precursor for a catalyst for electrocatalytic carbon dioxide reduction for the preparation of an electrode for the electrocatalytic carbon dioxide reduction catalyst.

4. The application of claim 3, which comprises the following steps:

firstly, preparing catalyst precursor slurry: dispersing 5-10 mg of catalyst in 0.8-1.2 ml of deionized water, isopropanol and 5wt% of Nafion mixed solution, and performing ultrasonic dispersion for 25-35 minutes to obtain slurry; then:

(II) preparing catalyst electrodes, wherein the catalyst electrodes comprise two types:

(1) preparing a glassy carbon working electrode loaded with a catalyst film by a dropping method: dropping 4-6 microliters of slurry on a glassy carbon electrode with the surface area of 0.07 square centimeter, and naturally drying to obtain a working electrode; then, applying a constant potential by using an electrochemical workstation for activation; the resulting catalyst pair CH₄Has high selectivity, and the activated catalyst is named as CH₄-a Cu catalyst;

(2) dispersing halogen-doped basic copper chloride and a binder in a mixed solvent of ethanol and water, and after ultrasonic dispersion, dropwise coating catalyst slurry on a catalyst carrier; and drying to obtain the catalyst electrode.

5. The use according to claim 4, wherein the binder is a 5% perfluorosulphonic polymer solution and the specific gravity of the binder in the catalyst slurry is 5-10%.

6. The use of claim 5, wherein the catalyst carrier is carbon paper, carbon cloth, carbon felt, metal foam or metal foil, and the loading of the catalyst is 2-20 mg/cm²。

7. The use of claim 6, wherein the conductive agent such as carbon black, carbon nanotube, graphene, etc. with a specific gravity of 10-30% can be added.

Technical Field

The invention belongs to the technical field of electrocatalysis carbon dioxide reduction catalysts, and particularly relates to a halogen-doped basic copper chloride catalyst precursor, and a preparation method and application thereof.

Background

The electrocatalytic carbon dioxide reduction has the potential of simultaneously solving the problems of clean energy development, greenhouse gas emission reduction, industrial raw material preparation and the like, so the electrocatalytic carbon dioxide reduction has important research value. Due to the rich d-electron structure of the copper element, the copper catalyst realizes various modes and strength adsorption of a primary product CO of carbon dioxide reduction, and can realize different CO activation modes and different reaction paths, so that the copper catalyst can realize the preparation of various reduction products. However, since the electrocatalytic carbon dioxide reduction reaction path is complicated and competing products are numerous, it is extremely difficult to achieve high selectivity of a single product. In the carbon dioxide reduction, the transition state CO can determine a catalytic reaction path and a product type, and the adsorption and activation of the CO on the surface of the catalyst are influenced by a series of factors, including catalyst factors such as a local structure of the catalyst, a particle size of the catalyst, a crystal boundary and a crystal face, and catalytic reaction condition factors such as an applied potential, an electrolyte type, a local pH value and an electrolyte concentration. Wherein the under-coordinated copper catalyst favors the hydrogenation of CO to CHO, thereby promoting CH₄And (4) generating. But localized Cu⁰/Cu⁺The microstructure is favorable for promoting the coupling reaction to generate C₂H₄. By introducing different halogen doping into the catalyst precursor, the microstructure of the catalyst can be regulated, so that the intermediate state adsorption property can be regulated, and the catalytic reaction path and the catalytic product can be regulated.

Disclosure of Invention

The invention aims to provide a method for preparing p-CH with high catalytic activity for electrocatalytic carbon dioxide reduction reaction₄A catalyst precursor halogen-doped basic copper chloride compound with high selectivity, a preparation method and application thereof.

The catalyst precursor halogen-doped basic copper chloride compound for the electrocatalytic carbon dioxide reduction reaction is prepared by a sol-gel method, wherein the halogen is one of bromine or iodine and accounts for 1% -20%.

The preparation method of the halogen-doped basic copper chloride compound provided by the invention specifically adopts an epoxy propane auxiliary hydrolysis method; the method comprises the following specific steps:

first, ethanol and isopropanol were mixed in a vessel, and CuCl was added₂And KBr or KI, stirring until the KBr or the KI is dissolved; adding deionized water into the solution, and then slowly dropwise adding propylene oxide; standing for 12-36 hours, adding acetone into the container, transferring the container into a centrifuge tube, and continuously standing for 80-120 hours; and finally, centrifuging for 5-8 times by using a high-speed centrifuge and acetone as a solvent, drying the product, grinding and collecting to obtain a catalyst precursor bromine or iodine doped basic copper chloride.

The halogen-doped basic copper chloride prepared by the invention can be used as a precursor of a catalyst for electrocatalytic carbon dioxide reduction reaction to prepare an electrode of the catalyst for electrocatalytic carbon dioxide reduction reaction, and the preparation method comprises the following specific steps:

firstly, preparing catalyst precursor slurry: dispersing 5-10 mg of catalyst in 0.8-1.2 ml of deionized water, isopropanol and 5wt% of Nafion mixed solution, and performing ultrasonic dispersion for 25-35 minutes to obtain slurry; then:

and (II) preparing a catalyst electrode. There may be two types:

(1) preparing a glassy carbon working electrode loaded with a catalyst film by a dropping method: dropping 4-6. mu.l of the slurry onto a surface area of 0.07 cm²Naturally drying the glassy carbon electrode to obtain a working electrode; then, applying a constant potential by using an electrochemical workstation for activation; the resulting catalyst pair CH₄Has high selectivity, and the activated catalyst is named as CH₄-a Cu catalyst;

(2) dispersing halogen-doped basic copper chloride and a binder in a mixed solvent of ethanol and water, and after ultrasonic dispersion, dropwise coating catalyst slurry on a catalyst carrier; drying to obtain a catalyst electrode;

wherein the binder is a 5% perfluorosulfonic acid polymer solution, and the specific gravity of the binder in the catalyst slurry is 5-10%.

Wherein, the catalyst carrier can be carbon paper, carbon cloth, carbon felt, metal foam or metal foil, etc., and the loading capacity of the catalyst is 2-20 mg/cm²。

Wherein, carbon black, carbon nano tube, graphene and other conductive agents with the specific gravity of 10-30% can also be added.

In the invention, halogen doping can promote the formation of the specific surface micro-morphology and structure of the basic copper chloride catalyst precursor in the catalyst activation process, and regulate and control the catalyst structure, further regulate and control the catalytic reaction path, and change the catalyst selectivity. The sol-gel method has simple process, can realize the high-selectivity electrocatalysis of carbon dioxide to reduce to generate methane or ethylene, the bromine-doped basic copper chloride catalyst has the methane Faraday efficiency of 59 percent and the carbon selectivity of 83 percent; the iodine-doped basic copper chloride has the advantages that the Faraday efficiency of ethylene reaches 71%, the carbon selectivity reaches 93%, and the iodine-doped basic copper chloride has a good application prospect in the field of electrocatalysis of carbon dioxide reduction.

Drawings

FIG. 1 is a scanning electron microscope image of bromine-doped copper oxychloride and iodine-doped copper oxychloride. Wherein, (a) and (b) are SEM images of bromine-doped basic copper chloride precursors under different times; (c) and (d) SEM images of the iodine-doped copper oxychloride precursor under different times.

FIG. 2 shows XPS results of bromine-doped basic copper chloride and iodine-doped basic copper chloride after activation. Wherein, (a), (b) and (c) are bromine-doped basic copper chloride Cu 2PXPS spectrograms, Cl 2PXPS, Br 3dXPS spectrograms; (d) and (e) and (f) are iodine doped copper oxychloride Cu 2PXPS spectrogram, Cl 2PXPS, I3 dXPS spectrogram.

FIG. 3 is a scanning electron microscope and a transmission electron microscope image of bromine-doped copper oxychloride and iodine-doped copper oxychloride after activation. Wherein, (a) is a bromine-doped copper oxychloride SEM image after activation; (b) TEM image of bromine-doped basic copper chloride after activation; (c) SEM image of bromine-doped basic copper chloride after activation; (d) TEM image of iodine doped basic copper chloride after activation.

FIG. 4 is a schematic diagram of a difference electron microscope showing the spheres of bromine-doped copper oxychloride and iodine-doped copper oxychloride after activation. Wherein, (a) is bromine-doped basic copper chloride after activation; (b) doping basic copper chloride for activated iodine.

FIG. 5 shows the carbon dioxide reduction results of bromine-doped basic copper chloride and iodine-doped basic copper chloride after activation. Wherein the potential is-1.71 Vvs. RHE, and the electrolyte is 0.05 MKHCO₃. (a) The faradaic efficiency distribution of bromine-doped basic copper chloride after activation; (b) the faradaic efficiency distribution of the activated iodine doped basic copper chloride is shown.

Detailed Description