阅读说明：本技术 一种用于生产甲酸和甲酸盐的金属催化剂制备方法 (Preparation method of metal catalyst for producing formic acid and formate ) 是由 钟苗 张明哲 于 2021-08-31 设计创作，主要内容包括：本发明属于电催化还原二氧化碳催化剂开发技术领域,具体为一种用于生产甲酸和甲酸盐的金属催化剂制备方法,所述制备方法如下：将一种主催化剂金属X和另一种导电金属Y合成一种具有高效电催化活性的双金属或合金材料主催化剂金属,主催化剂金属X为锡Sn,铅Pb,铟In,铋Bi或镓Ga,导电金属Y为Cu,共沉积在基底上,得到催化剂层,所述基底为导电基底或扩散气体电极基底。所选用的金属材料储量丰富,绿色无毒。所采用的方法一步制备,重复性好,可大规模制备。双金属或合金元素在大面积材料中组分和含量均匀分布。被发明制备的材料用于电催化还原二氧化碳制甲酸,在0.4～2.0A cm～(-2)的宽电流密度范围内。(The invention belongs to the technical field of development of electrocatalytic reduction carbon dioxide catalysts, and particularly relates to a preparation method of a metal catalyst for producing formic acid and formate, which comprises the following steps: synthesizing a main catalyst metal X and another conductive metal Y into a bimetal or alloy material main catalyst metal with high-efficiency electrocatalytic activity, wherein the main catalyst metal X is tin Sn, lead Pb, indium In, bismuth Bi or gallium Ga, and the conductive metal Y is Cu, co-depositing on a substrate to obtain a catalyst layer, and the substrate is a conductive substrate or a diffusion gas electrode substrate. The selected metal material has rich reserves, is green and nontoxic. The method has the advantages of one-step preparation, good repeatability and large-scale preparation. The components and contents of the bimetal or the alloy elements are uniformly distributed in the large-area material. The material prepared by the invention is used for electrocatalysisThe formic acid prepared from the original carbon dioxide is 0.4-2.0A cm ‑2 Within a wide range of current densities.)

1. A preparation method of a metal catalyst for producing formic acid and formate comprises the following steps: synthesizing a main catalyst metal X and another conductive metal Y into a bimetal or alloy material main catalyst metal with high-efficiency electrocatalytic activity, wherein the main catalyst metal X is tin Sn, lead Pb, indium In, bismuth Bi or gallium Ga, and the conductive metal Y is Cu, co-depositing on a substrate to obtain a catalyst layer, and the substrate is a conductive substrate or a diffusion gas electrode substrate.

2. The method for preparing a metal catalyst for producing formic acid and formate according to claim 1, wherein: the prepared main catalyst metal of the bimetal or alloy material is a solid film or a nano structure of the bimetal or alloy material and is used for a metal electrocatalyst or an electrode material.

3. The method for preparing a metal catalyst for producing formic acid and formate according to claim 1, wherein: the synthesis method of the main catalyst metal X and the other conductive metal Y is thermal evaporation coating, magnetron sputtering, hydrothermal synthesis or electrodeposition.

4. The method for preparing a metal catalyst for producing formic acid and formate according to claim 3, wherein: the preparation method comprises the steps of thermal evaporation coating, loading a main catalyst metal X and a conductive metal Y in an evaporation boat respectively, placing the evaporation boat below a conductive substrate or a diffusion gas electrode substrate, and heating the main catalyst metal X and the conductive metal Y to gasify and deposit the main catalyst metal X and the conductive metal Y on the conductive substrate or the diffusion gas electrode substrate to form a solid film or a micro-nano structure to obtain the XY bimetal or alloy electrocatalyst material, wherein the molar content of X in XY is 0.1-99.9%, and the molar content of Y in XY is 0.1-99.9%.

5. The method for preparing a metal catalyst for producing formic acid and formate according to claim 4, wherein: the heating evaporation conditions of the metal X are as follows: deposition rate under vacuum The heating evaporation conditions of the metal Y are as follows: deposition rate under vacuum

6. The method for preparing a metal catalyst for producing formic acid and formate according to claim 4, wherein: the thickness of the catalyst layer was monitored during deposition using a crystal oscillator plate and after preparation the thickness of the catalyst layer was measured using a film thickness gauge.

7. The method for preparing a metal catalyst for producing formic acid and formate according to claim 4, wherein: the deposition rates of the main catalyst metal X and the conductive metal Y determine the proportion of X, Y metal in the bimetallic or alloy material, the deposition rates of the main catalyst metal X and the conductive metal Y determine the proportion of X, Y metal in XY, and the component proportion of XY is regulated and controlled by regulating and controlling the deposition rates.

8. Use of a metal catalyst for the production of formic acid and formate salts, characterized in that:

the solid film or micro-nano structure material of the bimetal or alloy material is used for electrocatalysis.

9. Use of a metal catalyst according to claim 8 for the production of formic acid and formate salts, characterized in that: for electrocatalytic reduction of carbon dioxide to at least one single carbon product; the electrocatalytic process is carried out in an alkaline electrolyte.

Technical Field

The invention relates to the technical field of development of electrocatalytic reduction carbon dioxide catalysts, in particular to a preparation method of a metal catalyst for producing formic acid and formate.

Background

The wide use of fossil fuels discharges a large amount of carbon dioxide, causes global problems such as greenhouse effect, environmental pollution and the like, and the global carbon dioxide emission amount is over 370 hundred million tons according to the report of 2019 of the international energy agency. Therefore, the temperature of the molten metal is controlled,introducing CO₂The conversion into high value-added chemicals has the double meanings of reasonable utilization of carbon resources and environmental protection, and has attracted wide attention at home and abroad in recent years.

CO₂The products of the reduction are numerous and typically include carbon monoxide (CO), methane (CH)₄) Ethylene (C)₂H₄) The gaseous products and formic acid (HCOOH), ethanol (C)₂H₅OH) and the like. Among a plurality of products, formic acid and formate are basic chemical raw materials with large demand, and are widely applied to the industries of pharmacy, electrolytic metallurgy, leather and the like. In addition, formic acid and formates are also considered to be useful directly in formic acid fuel cells and other electrochemical devices due to their safety, non-toxicity, low volatility, transportability, and like advantages.

At present, the technical research of electrocatalytic reduction of carbon dioxide cannot be achieved under the condition of large current (more than 1 Acm)^-2) The performance index of stable formic acid production, how to greatly improve the current density of preparing formic acid by electrically reducing carbon dioxide, obtain higher electrocatalytic carbon dioxide reduction activity and improve the stability of the catalyst are still challenges. In view of this, by regulating and controlling the composition of the catalyst components and the structure of the regional micro-region, a large-area alloy or multi-metal catalyst material with uniform, phase-splitting-free and controllable surface physicochemical properties is obtained, the adsorption model and adsorption energy of carbon dioxide molecules on the surface can be effectively regulated, the concentrations of hydrogen ions and hydroxyl ions on the surface of the catalyst can be regulated, high electrocatalytic carbon dioxide reduction performance including high current density, high electrocatalytic selectivity, long stability and the like is realized, and the possibility is provided for the industrial development of the electrocatalytic carbon dioxide reduction material. For this reason, a corresponding technical scheme needs to be designed for solution.

Disclosure of Invention

The invention aims to provide a preparation method of a metal catalyst for producing formic acid and formate, which aims to solve the problem that the prior technical research on electrocatalytic reduction of carbon dioxide in the background art cannot achieve the purpose of large current (more than 1A cm)^-2) The performance index of formic acid production is stabilized, how to greatly improve the current density of preparing formic acid by electroreduction of carbon dioxide and obtain higher electrocatalytic carbon dioxide reductionActivity and improved catalyst stability remain a challenging problem.

In order to achieve the purpose, the invention provides the following technical scheme: a preparation method of a metal catalyst for producing formic acid and formate comprises the following steps: synthesizing a main catalyst metal X and another conductive metal Y into a bimetal or alloy material main catalyst metal with high-efficiency electrocatalytic activity, wherein the main catalyst metal X is tin Sn, lead Pb, indium In, bismuth Bi or gallium Ga, and the conductive metal Y is Cu, co-depositing on a substrate to obtain a catalyst layer, and the substrate is a conductive substrate or a diffusion gas electrode substrate.

Preferably, the prepared main catalyst metal of the bimetallic or alloy material is a solid film or a nano structure of the bimetallic or alloy material and is used for a metal electrocatalyst or an electrode material.

Preferably, the synthesis method of the main catalyst metal X and the other conductive metal Y is a thermal evaporation coating method, a magnetron sputtering method, a hydrothermal synthesis method or an electrodeposition method.

Preferably, the preparation method is thermal evaporation coating, the main catalyst metal X and the conductive metal Y are respectively loaded in an evaporation boat and placed below the conductive substrate or the diffusion gas electrode substrate, and the main catalyst metal X and the conductive metal Y are gasified by heating and deposited on the conductive substrate or the diffusion gas electrode substrate to form a solid film or a micro-nano structure, so as to obtain the XY bimetal or alloy electrocatalyst material, wherein the molar content of X in XY is 0.1-99.9%, and the molar content of Y in XY is 0.1-99.9%.

Preferably, the heating evaporation conditions of the metal X are as follows: deposition rate under vacuumThe heating evaporation conditions of the metal Y are as follows: deposition rate under vacuum

Preferably, the thickness of the catalyst layer is monitored by a crystal oscillator during deposition, and after preparation, the thickness of the catalyst layer is measured by a film thickness meter.

Preferably, the deposition rates of the main catalyst metal X and the conductive metal Y determine the proportion of X, Y metals in the bimetallic or alloy material, the deposition rates of the main catalyst metal X and the conductive metal Y determine the proportion of X, Y metals in XY, and the component proportion of XY is regulated and controlled by regulating and controlling the deposition rates.

Preferably, the solid film or micro-nano structure material of the bimetallic or alloy material is used for electrocatalysis.

Preferably, for electrocatalytic reduction of carbon dioxide to at least one single carbon product; the electrocatalytic process is carried out in an alkaline electrolyte.

Compared with the prior art, the invention has the beneficial effects that:

the metal material selected by the invention has rich reserves, and is green and nontoxic. The method has the advantages of one-step preparation, good repeatability and large-scale preparation. The components and the contents (the molar content of Cu is 0.1-99.9%, and the molar content of Sn is 0.1% -99.9%) of the bimetal or alloy elements in the large-area material are uniformly distributed. The prepared material is used for preparing formic acid by electrocatalytic reduction of carbon dioxide, and the concentration of the prepared material is 0.4-2.0A cm^-2The Faraday efficiency of formic acid can reach 94-80% within a wide current density range; at 1.6A cm^-2Under the current density, the Faraday efficiency of the formic acid can reach 90 percent; and the method can be stable for a long time, and has good practical value and application prospect.

Drawings

FIG. 1 is a scanning electron microscope image of a CuSn metal catalyst, a representative material prepared in accordance with the present invention;

FIG. 2 is a graph of an energy spectrum analysis of a representative material CuSn metal catalyst prepared in accordance with the present invention;

FIG. 3 is a scanning electron microscope image and a spectrum analysis chart of a series of CuSn metal catalysts with different components prepared by the invention;

FIG. 4 is an X-ray diffraction pattern of a CuSn metal catalyst, a representative material prepared in accordance with the present invention;

FIG. 5 is a graph of LSV curves of different proportions of representative materials CuSn metal catalysts prepared in accordance with the present invention with the single metals Cu and Sn in a 1M KOH electrolyte;

FIG. 6 is a graph of the Faraday efficiencies of different proportions of representative CuSn metal catalysts prepared in accordance with the present invention with single metal Cu for formic acid production at different current densities;

FIG. 7 shows a representative Cu material prepared in accordance with the present invention_0.92Sn_0.08Faradaic efficiency diagram of formic acid produced by metal catalyst in different electrolyte solutions;

FIG. 8 shows a representative Cu material prepared in accordance with the present invention_0.92Sn_0.08Potential-time plots of the metal catalyst at different current densities;

FIG. 9 shows a representative Cu material prepared in accordance with the present invention_0.92Sn_0.08A Faraday efficiency diagram of formic acid produced by the metal catalyst under different current densities;

FIG. 10 shows a representative Cu material prepared in accordance with the present invention_0.92Sn_0.08The metal catalyst is at 1.2A cm^-2Electrocatalytic reduction of CO at current density₂Long term stability test results.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

Example 1

A method of preparing a copper-tin (CuSn) metal catalyst, comprising the steps of:

s1, loading the metal Cu and the metal Sn in a thermal evaporation boat (tungsten boat) respectively by a physical or chemical method (comprising thermal evaporation, magnetron sputtering, hydrothermal synthesis, electrodeposition and the like), and placing the thermal evaporation boat and the metal Sn below the PTFE substrate; and heating the metal Cu and the metal Sn to gasify the metal Cu and the metal Sn and depositing the metal Sn and the metal Sn on the PTFE substrate to form a solid film to obtain the CuSn bimetal or alloy electrocatalyst material.

In step S1, the heating evaporation conditions of the metal Cu are: under the condition of certain vacuum degree, the current is 160A, the voltage is 2.8V, and the deposition rate isThe heating evaporation conditions of the metal Sn are as follows: under the condition of certain vacuum degree, the current is 120A, the voltage is 1.9V, and the deposition rate is

Further, the thickness of the prepared material is monitored by using a crystal oscillator plate in the deposition process, and the thickness of the prepared material is 500-1500 nm.

Further, the deposition rate of the metal Cu and the metal Sn determines the proportion of copper and tin in the CuSn metal catalyst material, and the component proportion of the CuSn metal catalyst can be regulated and controlled by regulating and controlling the deposition rate.

Further, by preference, Cu_1-xSn_{x(x＝0.08～0.12)}For the CuSn metal catalyst of the representative material prepared by the present invention, it can be seen from the scanning electron microscope image of fig. 1 that the CuSn metal catalyst is a dense film formed by close packing;

FIG. 2 is a spectrum analysis of a CuSn metal catalyst material as a representative material prepared by the present invention, and it can be clearly known that the element ratio of Cu to Sn in the obtained material is 92: 8;

FIG. 3 is a scanning electron microscope image and a spectrum analysis chart of a series of CuSn metal catalyst materials with different components prepared by the invention, which can clearly show that the material is a series of bimetallic materials with adjustable components;

FIG. 4 is an X-ray diffraction pattern of a CuSn metal catalyst, a representative material prepared in accordance with the present invention;

example 2

The difference in electrocatalytic activity of CuSn metal catalyst material and the monometallic Cu is understood by the following experiment.

In the experiment, a flow type electrolytic cell is adopted, and a CuSn bimetallic or alloy catalyst material and a single metal material Cu are respectively prepared on a PTFE substrate by a thermal evaporation coating method to serve as working electrodes. The reference electrode is an Ag/AgCl electrode, the counter electrode is foamed nickel, a linear voltammetry scanning method is adopted, the potential window is 0V-3V vs. RHE, and the scanning speed is 50 mV/s.

In the above experimental method, CO₂The gas flow rate is 30-100 sccm.

FIG. 6 shows CuSn metal catalysts at 1.2A cm in different proportions^-2～2.0A cm^-2Faradaic efficiency diagram of formic acid produced under current density, screening, Cu_0.92Sn_0.08The metallic material catalyst exhibits optimal catalytic performance. Wherein, the concentration is 1.6A cm^-2At current density, Cu_0.92Sn_0.08The Faraday efficiency of the metal catalyst material for electrically reducing carbon dioxide to produce formic acid can reach more than 80 percent and is 1.2A cm^-2At current density, Cu_0.92Sn_0.08The Faraday efficiency of the metal nano material catalyst for electrically reducing carbon dioxide to produce formic acid can reach more than 85 percent, which shows that Cu_0.92Sn_0.08The metal catalyst has good selectivity and catalytic activity to formic acid.

FIG. 7 is Cu_0.92Sn_0.08The faradaic efficiency diagram of formic acid generated by metal material in different electrolytes is screened, Cu_0.92Sn_0.08The metal catalyst material exhibits optimal catalytic performance when the electrolyte is 1M KOH plus 1M CsCl. Wherein, the concentration is 2.0A cm ^-2At current density, Cu_0.92Sn_0.08The Faraday efficiency of the metal catalyst for electrically reducing carbon dioxide to produce formic acid can reach about 85 percent and is 1.6A cm^-2At current density, Cu_0.92Sn_0.08The Faraday efficiency of the metal material catalyst for electrically reducing carbon dioxide to produce formic acid can reach over 90 percent, which shows that Cu is optimized by the electrolyte_0.92Sn_0.08The metal catalyst exhibits on formic acidBetter selectivity and catalytic activity.

FIG. 8 shows a representative Cu material prepared in accordance with the present invention_0.92Sn_0.08A potential-time diagram of the metal catalyst under different current densities when the electrolyte is 1M KOH plus 1M CsCl;

it can be seen from FIG. 9 that Cu is present after the electrolyte is optimized_0.92Sn_0.08The metal catalyst material is 0.4A cm^-2～2.0A cm^-2The Faraday efficiencies of formic acid are all higher than 85% under the current density, which shows that Cu_0.92Sn_0.08The metal catalyst has excellent activity of electrocatalytic reduction of carbon dioxide.

For Cu prepared in example 1_0.92Sn_0.08The metal catalyst material was subjected to a stability test. As can be seen from FIG. 10, in the stability test for 12 hours, at 1.2A cm^-2Under the current density of (2), the voltage change on the voltage-time curve is not obvious, which shows that the material stability is good.

While there have been shown and described the fundamental principles and essential features of the invention and advantages thereof, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing exemplary embodiments, but is capable of other specific forms without departing from the spirit or essential characteristics thereof; the present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein, and any reference signs in the claims are not intended to be construed as limiting the claim concerned.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.