阅读说明：本技术 一种基于irmof制备co2电催化还原材料的方法 (preparation of CO based on IRMOF2Method for electrocatalytic reduction of materials ) 是由 林鹏 曹雨 徐喆 吴天承 曾燮榕 于 2019-07-29 设计创作，主要内容包括：本发明公开一种基于IRMOF制备CO_2电催化还原材料的方法,其包括步骤：预先构建包括参比电极、对电极、工作电极以及电解液的电化学体系,其中,所述工作电极为玻碳；将IRMOF-8或IRMOF-1分散液负载到所述工作电极上；在对所述工作电极和参比电极施加电压的作用下,IRMOF-8或IRMOF-1中的COO-Zn键断裂,使Zn原位沉积在所述工作电极表面并生成用于CO_2电催化还原的Zn纳米颗粒。本发明利用IRMOF材料的结构高度均一以及化学稳定性较差的特点,在外加电压作用下使IRMOF中的COO-Zn键断裂,使Zn原位沉积在工作电极上,形成高度分散且尺寸均一的Zn纳米颗粒并用于电催化CO_2还原,从而大大提高CO_2还原的效率和CO的选择性。(the invention discloses a method for preparing CO based on IRMOF 2 A method of electrocatalytic reduction of a material comprising the steps of: an electrochemical system comprising a reference electrode, a counter electrode, a working electrode and electrolyte is constructed in advance, wherein the working electrode is glassy carbon; loading IRMOF-8 or IRMOF-1 dispersion onto the working electrode; under the action of applying voltage to the working electrode and the reference electrode, the COO-Zn bond in the IRMOF-8 or the IRMOF-1 is broken, so that Zn is deposited on the surface of the working electrode in situ and is generated for CO 2 Electrocatalytic reduced Zn nanoparticles. The invention is beneficialBy using the characteristics of high uniformity of the structure and poor chemical stability of the IRMOF material, the COO-Zn bond in the IRMOF is broken under the action of an external voltage, Zn is deposited on a working electrode in situ to form Zn nanoparticles with high dispersion and uniform size and the Zn nanoparticles are used for electrocatalysis of CO 2 Reduction to greatly increase CO 2 Efficiency of reduction and selectivity to CO.)

1. Preparation of CO based on IRMOF₂A method of electrocatalytic reduction of a material, comprising the steps of:

An electrochemical system comprising a reference electrode, a counter electrode, a working electrode and electrolyte is constructed in advance, wherein the working electrode is glassy carbon;

Loading IRMOF-8 or IRMOF-1 dispersion onto the working electrode;

Under the action of voltage applied to the working electrode and the reference electrode, the method is that in the IRMOF-8 or the IRMOF-1The COO-Zn bond is broken, so that Zn is deposited on the surface of the working electrode in situ and is generated for CO₂Electrocatalytic reduced Zn nanoparticles.

2. Production of CO based on IRMOF according to claim 1₂Method for electrocatalytic reduction of a material, characterized in that the preparation of the IRMOF-8 dispersion comprises the following steps:

Dissolving zinc nitrate hexahydrate and 2, 6-naphthalenedicarboxylic acid in N, N-dimethylformamide to obtain a mixed solution;

Heating the mixed solution to enable Zn in zinc nitrate hexahydrate and carboxyl in 2, 6-naphthalenedicarboxylic acid to be covalently combined to generate IRMOF-8;

And dispersing the IRMOF-8 and the conductive filler in a mixed solution of Nafion and ethanol, and performing ultrasonic treatment for 30-60 minutes to prepare the IRMOF-8 dispersion liquid.

3. Production of CO based on IRMOF according to claim 1₂Method for electrocatalytic reduction of a material, characterized in that the preparation of the IRMOF-1 dispersion comprises the following steps:

Dissolving zinc nitrate hexahydrate and terephthalic acid in N, N-dimethylformamide to obtain a mixed solution;

Heating the mixed solution to enable Zn in zinc nitrate hexahydrate to be covalently bonded with carboxyl in terephthalic acid to generate IRMOF-1;

And dispersing the IRMOF-1 and the conductive filler in a mixed solution of Nafion and ethanol, and performing ultrasonic treatment for 30-60 minutes to prepare the IRMOF-1 dispersion liquid.

4. production of CO based on IRMOF according to any of claims 2 to 3₂the method for electrocatalytic reduction of materials is characterized in that the conductive filler is any one of conductive carbon black, conductive graphite or conductive mica.

5. production of CO based on IRMOF according to any of claims 2 to 3₂method for electrocatalytic reduction of a material, characterized in that said heating is carried outThe temperature is 100-150 deg.C, and the time is 15-30 h.

6. production of CO based on IRMOF according to claim 1₂The method for electrocatalytic reduction of materials is characterized in that the reference electrode is an Ag/AgCl electrode, and the counter electrode is a platinum sheet electrode.

7. Production of CO based on IRMOF according to claim 1₂The method for electrocatalytic reduction of materials is characterized in that the magnitude of the voltage applied between the working electrode and the reference electrode is-1.7 to-2.1V.

8. Production of CO based on IRMOF according to claim 1₂Method for electrocatalytic reduction of a material, characterized in that said method is used for CO₂the grain size of the electrocatalytic reduced Zn nano-particles is more than 3 nm.

Technical Field

The invention relates to CO₂The field of electrocatalytic reduction materials, in particular to a method for preparing CO based on IRMOF₂A method of electrocatalytically reducing a material.

background

with the overuse of fossil dyes over the years, CO in the atmosphere and the ocean₂The concentration rises strongly, while CO₂Is the main gas responsible for the greenhouse effect, and therefore how to convert CO₂Concentration reduction is an issue that needs to be addressed. The prior art uses mainly catalytic reduction of CO₂Reducing to CO or other organic products, such as formic acid, ethylene, methane, etc., thus solving the problem of CO₂The greenhouse effect caused by overhigh concentration also solves the problem of energy scarcity.

Metal-organic frameworks (MOFS) materials are highly ordered supramolecular compounds composed of transition metal ions and organic ligands by self-assembly, and have the advantages of high specific surface area, high porosity, controllable pore structure, thermal stability and the like, and are gradually and widely used for catalyzing CO₂And (4) reducing. The metal organic framework is mainly divided into six series of materials including IRMOF, ZIF, CPL, MIL, PCN and UiO, and is currently reported to be used for electrocatalysis of CO₂The reduced MOF materials are mainly ZIF series, and the materials are mainly zeolite-like structures formed by self-assembling zinc nitrate hexahydrate and imidazole ligands. Wang et al reported the use of MOFs of the ZIF series for electrocatalysis of CO₂Reduction is carried out, but the faradaic efficiency of the generated CO is not high and is only about 65 percent, because Zn is not easy to break after being complexed with N, and when the Zn and the N form a complex material, N is mainly usedActs as a catalytic reduction to CO2, resulting in a reduction in the electrocatalytic activity of Zn.

Research has shown that metallic Zn is used as catalytic site to reduce CO₂The faradaic efficiency of the generated CO can be more than 80%, which greatly improves the CO₂However, the conventional techniques (such as electrodeposition) for preparing Zn have difficulty in preparing Zn particles with high dispersibility and uniform size.

Accordingly, the prior art is yet to be improved and developed.

Disclosure of Invention

In view of the above-mentioned deficiencies of the prior art, it is an object of the present invention to provide an IRMOF-based process for the production of CO₂a method for electrocatalytic reduction of materials, aiming at solving the problem that the prior art is difficult to realize the preparation of materials with high dispersity and uniform size for CO₂electrocatalytically reduced Zn particles.

The technical scheme of the invention is as follows:

preparation of CO based on IRMOF₂A method of electrocatalytically reducing a material, comprising the steps of:

An electrochemical system comprising a reference electrode, a counter electrode, a working electrode and electrolyte is constructed in advance, wherein the working electrode is glassy carbon;

Loading IRMOF-8 or IRMOF-1 dispersion onto the working electrode;

Under the action of applying voltage to the working electrode and the reference electrode, the COO-Zn bond in the IRMOF-8 or the IRMOF-1 is broken, so that Zn is deposited on the surface of the working electrode in situ and is generated for CO₂Electrocatalytic reduced Zn nanoparticles.

The IRMOF-based CO production₂a method for electrocatalytic reduction of a material, wherein the preparation of the IRMOF-8 dispersion comprises the steps of:

dissolving zinc nitrate hexahydrate and 2, 6-naphthalenedicarboxylic acid in N, N-dimethylformamide to obtain a mixed solution;

Heating the mixed solution to enable Zn in zinc nitrate hexahydrate and carboxyl in 2, 6-naphthalenedicarboxylic acid to be covalently combined to generate IRMOF-8;

And dispersing the IRMOF-8 and the conductive filler in a mixed solution of Nafion and ethanol, and performing ultrasonic treatment for 30-60 minutes to prepare the IRMOF-8 dispersion liquid.

The IRMOF-based CO production₂Method for electrocatalytic reduction of a material, characterized in that the preparation of the IRMOF-1 dispersion comprises the following steps:

dissolving zinc nitrate hexahydrate and terephthalic acid in N, N-dimethylformamide to obtain a mixed solution;

Heating the mixed solution to enable Zn in zinc nitrate hexahydrate to be covalently bonded with carboxyl in terephthalic acid to generate IRMOF-1;

And dispersing the IRMOF-1 and the conductive filler in a mixed solution of Nafion and ethanol, and performing ultrasonic treatment for 30-60 minutes to prepare the IRMOF-1 dispersion liquid.

The IRMOF-based CO production₂the method for electrocatalytic reduction of materials, wherein the conductive filler is any one of conductive carbon black, conductive graphite or conductive mica.

The IRMOF-based CO production₂The method for electrocatalytic reduction of materials, wherein the temperature of the heating treatment is 100-150 ℃ and the time is 15-30 h.

The IRMOF-based CO production₂The method for electrocatalytic reduction of materials, wherein the reference electrode is an Ag/AgCl electrode and the counter electrode is a platinum sheet electrode.

The IRMOF-based CO production₂The method for electrocatalytic reduction of materials, wherein the magnitude of the voltage applied between the working electrode and the reference electrode is-1.7 to-2.1V.

The IRMOF-based CO production₂method for electrocatalytic reduction of a material, wherein said is for CO₂The grain size of the electrocatalytic reduced Zn nano-particles is more than 3 nm.

has the advantages that: the invention provides a method for preparing CO based on IRMOF₂The method for electrocatalytic reduction of material utilizes the characteristics of uniform structure height and poor chemical stability of IRMOF (Zn-based metal organic framework) material to break COO-Zn bonds in the IRMOF under the action of external voltage so as to deposit Zn on a working electrode in situFormation of highly dispersed and uniformly sized Zn nanoparticles for electrocatalysis of CO₂Reduction to greatly increase CO₂The reduction efficiency and the CO selectivity are shown in the experimental result₂the electrocatalytic reduction material can convert CO₂The Faraday efficiency of the reduced product CO is improved to about 86 percent, and the selectivity of the CO is as high as 92.5 percent.

Drawings

FIG. 1 shows the preparation of CO based on IRMOF₂Flow diagram of a preferred embodiment of a method for electrocatalytic reduction of a material.

FIG. 2 shows the faradaic efficiency FE of CO at-1.0 to-1.5V (vs. RHE) voltages for Zn and electrodeposited Zn derived from IRMOF-8 and IRMOF-1_CO。

FIG. 3 is the current density j of CO at-1.0 to-1.5V (vs. RHE) voltage for Zn and electrodeposited Zn derived from IRMOF-8 and IRMOF-1_CO。

Detailed Description

The invention provides a method for preparing CO based on IRMOF₂The present invention will be described in further detail below in order to make the objects, technical solutions, and effects of the present invention clearer and clearer. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to FIG. 1, FIG. 1 shows a method for preparing CO based on IRMOF according to the present invention₂A flow chart of a preferred embodiment of a method for electrocatalytic reduction of a material, wherein, as shown, comprises the steps of:

S10, pre-constructing an electrochemical system comprising a reference electrode, a counter electrode, a working electrode and electrolyte, wherein the working electrode is glassy carbon;

S20, loading the IRMOF-8 or IRMOF-1 dispersion liquid on the working electrode;

S30, under the action of voltage applied to the working electrode and the reference electrode, the COO-Zn bond in the IRMOF-8 or the IRMOF-1 is broken, Zn is deposited on the surface of the working electrode in situ and is generated for CO₂Electrocatalytic reduced Zn nanoparticles.

In the embodiment, the IRMOF material is an MOF material synthesized by self-assembling a ligand with carboxyl and a Zn salt, and the IRMOF (Zn-based metal organic framework) material has the characteristics of high uniformity of structure and poor chemical stability, so that COO-Zn bonds in the IRMOF can be broken under the action of an external voltage, Zn is deposited on a working electrode in situ, and highly dispersed Zn nanoparticles with uniform size are formed and are used for electrocatalysis of CO₂reduction to greatly increase CO₂The reduction efficiency and the CO selectivity are shown in the experimental result₂The electrocatalytic reduction material can convert CO₂The Faraday efficiency of the reduced product CO is improved to about 86 percent, and the selectivity of the CO is as high as 92.5 percent.

The existing electrodeposition method is difficult to prepare the high-dispersity uniform-size CO for electrocatalysis₂the embodiment provides a method for electrically reducing Zn particles by using an IRMOF material containing a carboxyl ligand as a precursor, which utilizes the characteristics of high structural uniformity, large specific surface area and easiness in breakage of COO-Zn bonds of a metal organic framework material, and applies voltage to a working electrode and a reference electrode to deposit Zn on the surface of the working electrode in situ and generate the Zn particles for CO generation₂Electrocatalytic reduced Zn nanoparticles. The Zn nanoparticles prepared by the embodiment can be used as CO₂The reduction catalytic sites are highly uniformly dispersed in the carbon skeleton, thereby greatly improving CO₂efficiency of reduction and selectivity to CO.

In some embodiments, the preparation of the IRMOF-8 dispersion comprises the steps of: dissolving zinc nitrate hexahydrate and 2, 6-naphthalenedicarboxylic acid in N, N-dimethylformamide to obtain a mixed solution; heating the mixed solution to enable Zn in zinc nitrate hexahydrate and carboxyl in 2, 6-naphthalenedicarboxylic acid to be covalently combined to generate IRMOF-8; and dispersing the IRMOF-8 and the conductive filler in a mixed solution of Nafion and ethanol, and performing ultrasonic treatment for 30-60 minutes to prepare the IRMOF-8 dispersion liquid.

loading the IRMOF-8 dispersion liquid on the working electrode, applying voltage to the working electrode and the reference electrode to break COO-Zn bonds in the IRMOF-8 and make Zn in situdeposit on the working electrode surface and generate CO₂Electrocatalytic reduced Zn nanoparticles. Compared with the method of depositing Zn on the carbon skeleton or carbon black by adopting an electrodeposition method, the Zn derived from the IRMOF-8 in the embodiment can be highly uniformly dispersed in the carbon skeleton and has uniform size, and the reduced Zn can be directly subjected to CO without contacting with air₂Reduction detection, avoids the oxidation process of Zn, which can greatly improve CO₂The efficiency of the reduction.

In some embodiments, the preparation of the IRMOF-1 dispersion comprises the steps of: dissolving zinc nitrate hexahydrate and terephthalic acid in N, N-dimethylformamide to obtain a mixed solution; heating the mixed solution to enable Zn in zinc nitrate hexahydrate to be covalently bonded with carboxyl in terephthalic acid to generate IRMOF-1; and dispersing the IRMOF-1 and the conductive filler in a mixed solution of Nafion and ethanol, and performing ultrasonic treatment for 30-60 minutes to prepare the IRMOF-1 dispersion liquid.

Loading the IRMOF-1 dispersion liquid on the working electrode, applying voltage to the working electrode and the reference electrode to break COO-Zn bonds in the IRMOF-1, depositing Zn on the surface of the working electrode in situ and generating CO for CO₂Electrocatalytic reduced Zn nanoparticles. Compared with the method of depositing Zn on the carbon skeleton or carbon black by adopting an electrodeposition method, the Zn derived from the IRMOF-1 in the embodiment can be highly uniformly dispersed in the carbon skeleton and has uniform size, and the reduced Zn can be directly subjected to CO without contacting with air₂Reduction detection, avoids the oxidation process of Zn, which can greatly improve CO₂The efficiency of the reduction.

In some embodiments, the conductive filler is any one of conductive carbon black, conductive graphite, or conductive mica, but is not limited thereto. Preferably, the conductive filler is conductive carbon black, and the conductive carbon black is a material with excellent conductivity, and the dispersion formed by the conductive carbon black and the IRMOF material is loaded on the working electrode, so that the conductivity of the surface of the working electrode can be enhanced.

In some embodiments, during the process of preparing IRMOF-8 or IRMOF-1, the temperature of the heating treatment is 100 to 150 ℃ for 15 to 30 hours, and under the treatment conditions, the terephthalic acid or 2, 6-naphthalenedicarboxylic acid can react with Zn in the Zn salt to form IRMOF-1 or IRMOF-8.

In some embodiments, the reference electrode is an Ag/AgCl electrode and the counter electrode is a platinum sheet electrode.

In some embodiments, the voltage applied between the working electrode and the reference electrode is in the range of-1.7 to-2.1V, and in the voltage range, the COO-Zn bond in the IRMOF-1 or IRMOF-8 is easy to break, so that Zn is deposited on the surface of the working electrode in situ and is generated for CO₂Electrocatalytic reduced Zn nanoparticles.

In some embodiments, the Zn nanomaterial catalytic activity has a significant size effect, and studies have shown that when Zn nanoparticles are less than 3 nanometers in size, the catalytic activity is increased but selectivity to CO is lower than to H₂And when the size of Zn nanoparticles is greater than 3nm, the catalytic activity thereof is decreased but the selectivity to CO is remarkably increased, and gradually tends to be stable. The existing electrodeposition is difficult to realize and prepare Zn nanoparticles with high dispersity, uniform size and particle size larger than 3 nanometers, but the embodiment proposes that by utilizing the characteristics of high uniformity of structure and insufficient chemical stability of a Zn-based metal organic framework material, COO-Zn bonds are broken under the action of an applied voltage, Zn is deposited on a working electrode in situ to form a highly-dispersed material with uniform size and particle size larger than 3 nanometers for CO (carbon monoxide)₂Electrocatalytic reduced Zn nanoparticles.

The following is a description of an IRMOF-based CO production process according to the invention₂The method for electrocatalytic reduction of materials is further illustrated: