阅读说明：本技术 一种核壳结构的纳米Cu-Eu合金催化剂及其制备方法和应用 (Nano Cu-Eu alloy catalyst with core-shell structure and preparation method and application thereof ) 是由 王志江 单晶晶 于 2019-09-25 设计创作，主要内容包括：一种核壳结构的纳米Cu-Eu合金催化剂及其制备方法和应用,它涉及一种Cu基合金催化材料及其制备方法和应用。本发明的目的是要解决现有Cu催化还原CO<Sub>2</Sub>产CH<Sub>4</Sub>存在CH<Sub>4</Sub>的法拉第效率差、电流密度低的问题。一种核壳结构的纳米Cu-Eu合金催化剂以Cu为核,以Cu-Eu合金为壳复合而成。制备方法：一、称量；二、制备表面活性剂醇溶液；三、制备前驱体盐溶液；四、还原；五、分离、清洗、干燥,得到核壳结构的纳米Cu-Eu合金催化剂。它作为原料制备工作电极,用于电催化还原CO<Sub>2</Sub>制CH<Sub>4</Sub>。优点：用于CO<Sub>2</Sub>电催化还原产CH<Sub>4</Sub>的活性和选择性较高,稳定性好。(A nano Cu-Eu alloy catalyst with a core-shell structure and a preparation method and application thereof relate to a Cu-based alloy catalytic material and a preparation method and application thereof. The invention aims to solve the problem of CO catalytic reduction by using the existing Cu 2 Produce CH 4 Presence of CH 4 the problems of poor Faraday efficiency and low current density. The nanometer Cu-Eu alloy catalyst with a core-shell structure is compounded by taking Cu as a core and taking Cu-Eu alloy as a shell. The preparation method comprises the following steps: firstly, weighing; secondly, preparing a surfactant alcoholic solution; thirdly, preparing a precursor salt solution; fourthly, reduction; and fifthly, separating, cleaning and drying to obtain the core-shell structure nano Cu-Eu alloy catalyst. It is used as raw material for preparing working electrode for electrocatalytic reduction of CO 2 Manufacture of CH 4 . The advantages are that: for CO 2 Electrocatalytic reductionNative CH 4 Has high activity and selectivity and good stability.)

1. A nano Cu-Eu alloy catalyst with a core-shell structure is characterized in that the nano Cu-Eu alloy catalyst with the core-shell structure is compounded by taking Cu as a core and taking Cu-Eu alloy as a shell.

2. The preparation method of the core-shell structure nano Cu-Eu alloy catalyst according to claim 1, characterized in that the method is completed by the following steps:

Firstly, weighing: weighing a surfactant, an alcohol-containing organic solvent, a copper salt and a europium salt; the method comprises the following steps of (1) equally dividing a surfactant into a surfactant I and a surfactant II, and sequentially dividing an alcohol-containing organic solvent into the alcohol-containing organic solvent I and the alcohol-containing organic solvent II according to a volume ratio of 18: 4; the volume ratio of the substance of the surfactant to the alcohol-containing organic solvent is (0.002-2) mmol:22 mL; the molar ratio of the copper element in the copper salt to the europium element in the europium salt is 1-9: 1; the volume ratio of the sum of the amounts of the copper element and the europium element in the copper salt to the alcohol-containing organic solvent II is (0.02-0.2) mmol:22 mL;

secondly, preparing a surfactant alcoholic solution: dissolving a surfactant I in an alcohol-containing organic solvent I to obtain a surfactant alcohol solution;

Thirdly, preparing a precursor salt solution: dissolving a surfactant II, a copper salt and a europium salt in an alcohol-containing organic solvent II to obtain a precursor salt solution;

fourthly, reduction: stirring and heating the surfactant alcoholic solution obtained in the step two to 220-300 ℃; adding the precursor salt solution obtained in the third step into the surfactant alcoholic solution obtained in the second step at an addition rate of 0.05-0.3 mL/s, stirring and reacting at the temperature of 220-300 ℃ for 5-60 min, and cooling to room temperature at a cooling rate of 5-40 ℃/min after the reaction is finished to obtain a reaction product;

Fifthly, separation, cleaning and drying: and (3) carrying out centrifugal separation on the reaction product, sequentially washing the separated solid by using acetone, absolute ethyl alcohol and ultrapure water, washing for 1-3 times respectively to obtain a washed solid, and drying the washed solid in vacuum at room temperature for 12-24 hours to obtain the core-shell structure nano Cu-Eu alloy catalyst.

3. The method for preparing the core-shell structured nano Cu-Eu alloy catalyst according to claim 2, wherein the surfactant in the first step is sodium dodecyl benzene sulfonate, PVP K30 or CTAB.

4. the method for preparing the core-shell structured nano Cu-Eu alloy catalyst according to claim 2, wherein the copper salt in the first step is Cu (CH)₃COO)₂、CuCl₂·2H₂O or Cu (NO)₃)₂·3H₂O。

5. The method for preparing nanometer Cu-Eu alloy catalyst with core-shell structure according to claim 2, wherein in step one, the europium salt is Eu (NO)₃)₃·5H₂O、EuCl₃·6H₂O or Eu (CH)₃COO)₃·nH₂O。

6. The method for preparing the core-shell structured nano Cu-Eu alloy catalyst according to claim 2, wherein the alcohol-containing organic solvent in the step one is ethylene glycol, diethylene glycol or triethylene glycol.

7. The application of the nano Cu-Eu alloy catalyst with the core-shell structure is characterized in that the nano Cu-Eu alloy catalyst with the core-shell structure is used as a raw material for preparing a working electrode for electrocatalytic reduction of CO₂Manufacture of CH₄。

Technical Field

The invention relates to a Cu-based alloy catalytic material and a preparation method and application thereof.

background

Since the industrial revolution, the human society has rapidly developed, and the demand for fossil energy such as coal, oil, natural gas, etc. has been increasing. Excessive mining and use of these fossil fuels not only leads to a stressful energy crisis, but also causes atmospheric CO₂the concentration rises rapidlyhigh and thus bring about a range of global climate change. But CO as the most predominant greenhouse gas₂CO, not at all, in the fields of green chemistry and organic synthesis₂Is a chemical raw material with rich sources, low price, easy obtaining, no toxicity and no harm. To reduce greenhouse gas emissions while effectively relieving energy demand, it is desirable to utilize CO₂As a hydrogen storage medium, converting it to CH₃OH、CH₄、C₂H₄the special fuel can be named as one arrow double carving, and has great development potential. Wherein carbon dioxide is converted to methane (CO)₂+4H₂→CH₄+2H₂O) converts a molecule that is difficult to store and transport (hydrogen) into a molecule that is relatively easy to store (methane), CH compared to hydrogen₄easy liquefaction allows for safer storage and transport. CO 2₂the resource recycling has various ways, and methods such as catalytic hydrogenation, photocatalytic reduction, electrocatalytic reduction and the like are available. In which the CO is reduced electrocatalytically₂Mild reaction conditions, no need of high temperature and high pressure, flexible equipment operation, high energy utilization efficiency, and can regulate and control product selectivity and reaction speed by simply changing electrolysis conditions, so the method is considered to be CO₂the transformation technology with the most development prospect in resource utilization.

At present, electrocatalysis can not reach the standard of industrial production, and one of the main reasons is that the performance of the catalyst is poor. Therefore, the desire to achieve high performance electrocatalysis is dependent on the development of cathode materials. The common catalysts at present are: metal catalysts, non-metal catalysts, and molecular catalysts. Among them, the metal catalyst has been widely studied because of its mild reaction conditions, simple operation and many active sites. Compared with a single metal catalyst, the alloy catalyst is flexible in design, various in types and various in structure, often shows more excellent catalytic performance than the single metal forming the alloy catalyst, and is favored by researchers in the field of energy catalysis. In CO₂In the electrocatalytic reduction reaction, the alloying process regulates and controls the binding energy of a reaction intermediate on the surface of the catalyst by changing the structure and the components of the catalyst, thereby achieving the purposes of reducing the reaction overpotential and improving the selectivity of a specific productthe purpose is. Thus, Cu-based binary and even multi-element alloy electrocatalysts are becoming CO₂Hot spots in the RR domain.

Disclosure of Invention

The invention aims to solve the problem of CO catalytic reduction by using the existing Cu₂Produce CH₄Presence of CH₄The problems of poor Faraday efficiency and low current density; and provides a nano Cu-Eu alloy catalyst with a core-shell structure and a preparation method and application thereof.

A nano Cu-Eu alloy catalyst with a core-shell structure is compounded by taking Cu as a core and taking Cu-Eu alloy as a shell.

A preparation method of a nano Cu-Eu alloy catalyst with a core-shell structure is specifically completed according to the following steps:

Firstly, weighing: weighing a surfactant, an alcohol-containing organic solvent, a copper salt and a europium salt; the method comprises the following steps of (1) equally dividing a surfactant into a surfactant I and a surfactant II, and sequentially dividing an alcohol-containing organic solvent into the alcohol-containing organic solvent I and the alcohol-containing organic solvent II according to a volume ratio of 18: 4; the volume ratio of the substance of the surfactant to the alcohol-containing organic solvent is (0.002-2) mmol:22 mL; the molar ratio of the copper element in the copper salt to the europium element in the europium salt is 1-9: 1; the volume ratio of the sum of the amounts of the copper element and the europium element in the copper salt to the alcohol-containing organic solvent II is (0.02-0.2) mmol:22 mL;

secondly, preparing a surfactant alcoholic solution: dissolving a surfactant I in an alcohol-containing organic solvent I to obtain a surfactant alcohol solution;

Thirdly, preparing a precursor salt solution: dissolving a surfactant II, a copper salt and a europium salt in an alcohol-containing organic solvent II to obtain a precursor salt solution;

Fourthly, reduction: stirring and heating the surfactant alcoholic solution obtained in the step two to 220-300 ℃; adding the precursor salt solution obtained in the third step into the surfactant alcoholic solution obtained in the second step at an addition rate of 0.05-0.3 mL/s, stirring and reacting at the temperature of 220-300 ℃ for 5-60 min, and cooling to room temperature at a cooling rate of 5-40 ℃/min after the reaction is finished to obtain a reaction product;

Fifthly, separation, cleaning and drying: and (3) carrying out centrifugal separation on the reaction product, sequentially washing the separated solid by using acetone, absolute ethyl alcohol and ultrapure water, washing for 1-3 times respectively to obtain a washed solid, and drying the washed solid in vacuum at room temperature for 12-24 hours to obtain the core-shell structure nano Cu-Eu alloy catalyst.

Application of nano Cu-Eu alloy catalyst with core-shell structure as raw material for preparing working electrode for electrocatalytic reduction of CO₂Manufacture of CH₄。

the invention has the advantages that:

Firstly, the rare earth resources in China are rich in reserves, have the advantages of complete mineral species and rare earth elements, reasonable rare earth grade and mineral site distribution and the like, but are used for Cu-based alloying and electrocatalytic reduction of CO₂realization of CO₂To CH₄Has not been reported. The nano Cu-Eu alloy catalyst with the core-shell structure prepared by the invention is used for CO₂Electrocatalytic reduction of CH₄Has higher activity and selectivity.

Secondly, in the nano Cu-Eu alloy catalyst with the core-shell structure, Cu-Eu alloy is uniformly distributed outside Cu particles to form an amorphous shell layer, no agglomeration occurs among the alloy particles, and the stability is good;

Thirdly, the nano Cu-Eu alloy catalyst with the core-shell structure prepared by the invention shows obvious alloy effect, and the addition of Eu effectively improves CH₄the product selectivity of (a) while inhibiting the formation of other products; when the molar ratio of the copper element to the europium element in the nano Cu-Eu alloy catalyst is 9:1, the catalyst has CH when the potential of the working electrode relative to the reference electrode is-2V₄The highest Faraday efficiency can reach 74 percent, which is 3.5 times that of the Cu nano particles.

drawings

FIG. 1 is a TEM image of Cu nanoparticles prepared in example 4;

FIG. 2 is a TEM image of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 1;

FIG. 3 is an HR-TEM image of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 1;

FIG. 4 is an EDS-Mapping chart of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 1;

FIG. 5 is a TEM image of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 2;

FIG. 6 is a TEM image of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 3;

FIG. 7 is an XRD pattern, in which a represents a standard card pattern of XRD of metallic copper (pdf: 04-0836), b represents an XRD pattern of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 1, c represents an XRD pattern of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 2, d represents an XRD pattern of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 3, and e represents an XRD pattern of the Cu nanoparticles prepared in example 4;

FIG. 8 is a XPS high resolution spectrum of Cu element, wherein a) shows the XPS high resolution spectrum of Cu element of Cu nanoparticle prepared in example 4, b) shows the XPS high resolution spectrum of Cu element of core-shell structured nano Cu-Eu alloy catalyst prepared in example 1, c) shows the XPS high resolution spectrum of Cu element of core-shell structured nano Cu-Eu alloy catalyst prepared in example 2, and d) shows the XPS high resolution spectrum of Cu element of core-shell structured nano Cu-Eu alloy catalyst prepared in example 3;

FIG. 9 is a high resolution XPS spectrum of Eu, wherein a) represents the high resolution XPS spectrum of Eu in the core-shell structured nano Cu-Eu alloy catalyst prepared in example 1, b) represents the high resolution XPS spectrum of Eu in the core-shell structured nano Cu-Eu alloy catalyst prepared in example 2, and c) represents the high resolution XPS spectrum of Eu in the core-shell structured nano Cu-Eu alloy catalyst prepared in example 3;

FIG. 10 is CH₄A in the current density chart, a represents CH of the Cu nanoparticles prepared in example 4₄B represents CH of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 1₄C represents CH of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 2₄D represents the product of example 3CH of prepared nano Cu-Eu alloy catalyst with core-shell structure₄A current density map of (a);

FIG. 11 is CH₄A represents CH of the Cu nanoparticles prepared in example 4₄Faraday efficiency graph, b represents CH of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 1₄Faraday efficiency graph, c represents CH of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 2₄Faraday efficiency graph, d represents CH of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 3₄Faraday efficiency plot;

FIG. 12 is CH₄Wherein a represents CH of the Cu nanoparticles prepared in example 4₄B represents CH of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 1₄C represents CH of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 2₄D represents CH of the core-shell structured nano Cu-Eu alloy catalyst prepared in example 3₄mass activity map of (1).

Detailed Description