CN114262916B

CN114262916B - Preparation method of nano mesoporous gold film loaded copper oxide cluster material and application of nano mesoporous gold film loaded copper oxide cluster material in ethanol preparation

Info

Publication number: CN114262916B
Application number: CN202111593180.5A
Authority: CN
Inventors: 严勇; 刘浩岑; 赵玉国
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2021-12-23
Filing date: 2021-12-23
Publication date: 2023-01-13
Anticipated expiration: 2041-12-23
Also published as: CN114262916A

Abstract

The invention relates to a preparation method of a nano mesoporous gold film loaded copper oxide cluster material and application of the nano mesoporous gold film loaded copper oxide cluster material in ethanol preparation. The invention adopts the electron beam evaporation technology to firstly deposit an Au/Ag double-layer film on an ITO substrate, and the nano mesoporous gold film is prepared through the processes of induced dehumidification and dealloying. And then filling copper into the nano mesoporous structure by a circulating liquid phase chemical copper plating method to form the nano mesoporous gold film loaded copper oxide cluster material. The invention synthesizes the nano mesoporous gold film loaded copper oxide cluster material by a simple, rapid, safe and controllable circulating liquid phase chemical copper plating method, increases the specific surface area of the material, improves the catalytic activity, reduces the activation energy barrier of carbon dioxide reduction by means of the plasmon effect of gold, and greatly promotes the reaction activity on a multi-carbon product.

Description

Preparation method of nano mesoporous gold film loaded copper oxide cluster material and application of nano mesoporous gold film loaded copper oxide cluster material in ethanol preparation

Technical Field

The invention belongs to the field of energy conversion and storage application, and particularly relates to a preparation method of a nano mesoporous gold film loaded copper oxide cluster material and application of the nano mesoporous gold film loaded copper oxide cluster material in preparation of ethanol by high-selectivity electrocatalytic reduction of carbon dioxide.

Background

FossilThe fuel can continuously release a large amount of CO into the atmosphere when being combusted for human use ₂ . Research shows that CO ₂ Is a main greenhouse gas, the growing population of the earth and the large-scale use of fossil energy tend to make CO in the atmosphere ₂ The concentration is continuously increased, and the development of the human economy and society is also restricted by the more prominent climate change problem. CO is introduced into ₂ The conversion into other substances for reuse is an effective way to solve the problem of carbon emission.

The electrocatalytic reduction reaction of carbon dioxide species on the electrode surface is often simply divided into three processes: (1) adsorption of carbon dioxide; (2) conversion of carbon dioxide; and (3) desorbing the product. The products of carbon dioxide reduction are numerous, such as carbon monoxide, methane, formic acid, methanol, ethylene, ethanol, acetic acid, and the like. The reason for such a large product distribution is that CO ₂ And the adsorption of intermediate products. The adsorption capacity of the reaction intermediate on the surface of the material can influence the thermodynamic energy barrier of electrocatalysis, and has important influence on the electrocatalysis performance. For the preparation of carbon monoxide, the noble metal generally has a higher selectivity for carbon monoxide. The main reason for this is that the noble metal has a strong adsorption energy for the intermediates COOH which produce carbon monoxide, and a poor adsorption energy for the product carbon monoxide. This can lower the thermodynamic energy barrier for the noble metal to form carbon monoxide, promoting its electrocatalytic properties.

Electrocatalytic CO ₂ The reduction reaction is a surface catalytic reaction, the main active sites of which are the active sites on the surface or interface of the electrocatalyst. Based on the relationship between the structure and performance of the material, the interfacial properties of the composite material can be changed along with the compounding of the material, thereby affecting the catalytic performance of the composite material. The synergistic effect of copper with other metals is also used for CO ₂ In the research of electro-catalytic reduction, the electronic structure of the alloy is adjusted by utilizing the interaction between metals, and the reaction intermediate is stabilized and the generation of hydrogen generation reaction can be inhibited. For example: jaramillo et al reported that gold nanoparticles were deposited by physical vapor deposition onto electrodes made of flat polycrystalline copper foil as electrocatalysts for CO ₂ The reduction to methanol has high activity. Au/Cu electrocatalysisThe selectivity of the agent for the production of products containing C-C bonds is more than 100 times higher than that of methane or methanol. (see text "Improved CO ₂ reduction activity towards C ₂₊ Thus it can be shown that gold/copper bimetallic electrocatalysts show a stronger synergistic activity and selectivity than gold, copper or AuCu alloys, but still present electrocatalytic CO ₂ The reduction performance is insufficient, and the C with higher economic value is difficult to directionally produce ₂₊ Problems with liquid phase products.

Meanwhile, considering that the activation energy barrier for carbon dioxide reduction is very high, metals such as Pt, au, cu and the like or alloy particles formed by the metals have a plasmon effect, and free electrons in the particles are induced by an incident light electromagnetic field with a specific wavelength to generate a collector type oscillation motion, so that the free electrons are promoted to be enriched and absorbed with photons in a space range far larger than a geometric cross section, and the energy of the electrons and a local electric field around the particles are obviously enhanced. So we prepared a nano-mesoporous gold film loaded copper oxide cluster material (hereinafter referred to as NP-Au-CuO for short) _X ) The material with the plasmon effect is applied to electrocatalysis reaction, and can play roles of enhancing the absorption capacity of sunlight, improving the separation efficiency of carriers, accelerating the reaction kinetics of surface catalysis and the like besides improving the reaction temperature of a system. The invention provides direct scientific basis and technical means for designing and constructing stable and efficient electrocatalytic oxygen evolution active materials.

Disclosure of Invention

Aiming at the existing electrocatalytic CO ₂ Reduction (CO) ₂ RR) catalyst activity is low, the product selectivity is poor, the invention constructs a nano mesoporous gold film loaded copper oxide cluster material on a conductive glass substrate by electron beam evaporation technology and circulating liquid phase chemical copper plating method for preparing ethanol by high-selectivity electrocatalytic reduction of carbon dioxide, reduces the activation energy barrier of carbon dioxide reduction by means of the plasmon effect of gold, and promotes the reaction of multi-carbon productsAnd (4) activity. In addition, the method also has the advantages of simple preparation, low cost, environmental protection and the like.

In order to realize the technical purpose of the invention, the invention provides a preparation method of a nano mesoporous gold film loaded copper oxide cluster material.

1. A preparation method of a nano mesoporous gold film loaded copper oxide cluster material is characterized by comprising the following steps:

s1, preparing a nano mesoporous gold film electrode: an Au/Ag double-layer film with the thickness of 5-10 nm Au/20nm Ag is deposited on the ITO substrate by adopting an electron beam evaporation technology, and heat treatment induction dehumidification treatment is carried out for 15min in an argon atmosphere at the temperature of 850-950 ℃. The dehumidified Au-Ag alloy particles were then immersed in a nitric acid solution at 21 ℃ for 5min (60-70wt% HNO) ₃ Solution) and then removing Ag, and performing dealloying treatment to obtain the nano mesoporous gold thin film electrode;

s2, controllable loading of the copper oxide cluster: preparing 5-10 mM hydrazine hydrate solution and 1-10 mM copper acetate solution by using ultrapure water as a reducing agent and a copper precursor respectively: and then soaking the nano mesoporous gold film electrode obtained in the step S1 in a hydrazine hydrate solution at room temperature for 20-30 min, adsorbing a reducing agent through a capillary effect, and then washing with deionized water to remove the excess hydrazine hydrate solution on the surface. Then, soaking the nano mesoporous gold film electrode absorbed with hydrazine hydrate in a copper acetate solution for 20-30 min at room temperature to ensure that Cu is in contact with the nano mesoporous gold film electrode ²⁺ Reducing, washing with deionized water again, and loading the copper oxide cluster on the nano mesoporous gold thin film electrode. By repeating the steps for a plurality of times, the copper oxide clusters in the material can be controllably loaded. And finally, vacuum drying for 2h at 90-100 ℃ by using a vacuum drying box to obtain the copper oxide cluster-loaded nano mesoporous gold film electrode.

Step S1, performing heat treatment on the 5nm Au/20nm Ag Au/Ag double-layer film at 900 ℃ in argon atmosphere for 15min to induce dehumidification, and 65wt% of HNO ₃ And (4) solution dealloying.

In the step S2, the reducing agent is hydrazine hydrate with the concentration of 10mM and the copper precursor is copper acetate solution with the concentration of 5mM, and the cyclic soaking time is 30min. The vacuum drying temperature is 100 ℃.

Due to the adoption of the technical scheme, the invention has the following advantages:

(1) The NP-Au-CuO of the invention _X The preparation and modification methods of the electrode are simple, the conditions are mild, and the operation is easy.

(2) Prepared NP-Au-CuO _X The electrode material has high specific surface area and excellent response signals, and shows good activity of electrocatalytic reduction of carbon dioxide.

(3) The activation energy barrier of carbon dioxide reduction is reduced by utilizing the plasmon effect of NP-Au, the reaction activity to a multi-carbon product is greatly promoted, and the effects of enhancing the absorption capacity of sunlight, improving the separation efficiency of carriers, accelerating the reaction kinetics of surface catalysis and the like can be exerted besides the improvement of the reaction temperature of a system.

Drawings

FIG. 1 is NP-Au-CuO _X A preparation process flow chart of the catalyst;

FIG. 2 is a physical diagram and an SEM diagram of a nano-mesoporous gold thin-film material prepared by the preparation method provided in example 1;

FIG. 3 is a CuO loaded nano-mesoporous gold film prepared by the preparation method provided in example 21 _X EDS mapping plot of electrode material;

FIG. 4 is NP-Au-CuO _X At N ₂ And CO ₂ Linear Sweep Voltammetry (LSV) curve under saturated electrolyte

FIG. 5 is NP-Au-CuO _X Electrocatalytic reduction of CO by electrode material plasma resonance effect ₂ Graph of performance comparison

FIG. 6 is NP-Au-CuO _X Electrode material CO at different potentials ₂ Timing current and Faraday efficiency map of RR

Detailed Description

In order that those skilled in the art will better understand the technical solution of the present invention, the present invention will be further described with reference to the following specific examples, which are not intended to limit the present invention.

Example 1

Deposition on an ITO substrate by electron beam evaporationAn Au/Ag double-layer film with the thickness of 5nm Au/20nm Ag is respectively formed, and heat treatment induction dehumidification treatment is carried out for 15min in an argon atmosphere at the temperature of 900 ℃. Then, the Au-Ag alloy particles dehumidified on the substrate were immersed in a nitric acid solution (65wt%; HNO) at 21 deg.C ₃ Solution) and performing dealloying treatment; the nano mesoporous gold thin film material (NP-Au) is prepared, and a figure 2 (figure 2) is obtained by observing a real object diagram and different multiplying powers in a scanning electron microscope, and has a good mesoporous structure.

Example 2

The preparation process is the same as that of example 1, except that: preparing a hydrazine hydrate solution with the concentration of 10mM and a copper acetate solution with the concentration of 5mM as a reducing agent and a copper precursor respectively: the NP-Au sample prepared in example 1 was then soaked in hydrazine hydrate solution at room temperature for 30min to adsorb the reducing agent by capillary effect, and then rinsed with deionized water to remove excess hydrazine hydrate solution on the surface. Then, soaking the nano mesoporous gold film electrode adsorbed with hydrazine hydrate in a copper acetate solution at room temperature for 30min to ensure that Cu is in contact with the copper acetate solution ²⁺ Reducing, washing with deionized water again to load the copper oxide cluster on the nano mesoporous gold film sample, and finally vacuum drying for 2h at 100 ℃ by using a vacuum drying oven. Prepare and obtain NP-Au-CuO _X the-1C electrode material is observed in a scanning electron microscope and has no obvious difference from the NP-Au microstructure, and in order to further prove that the copper oxide clusters are loaded on the nano mesoporous gold film sample, an EDS mapping test is carried out, and a figure 3 is obtained by observation, so that the copper oxide clusters are uniformly loaded on the nano mesoporous gold film sample.

Example 3

The preparation process is the same as that of example 2, and only differs from the following steps: the NP-Au sample is soaked in hydrazine hydrate solution and washed for 3 times, and then soaked in copper acetate solution for 30min at room temperature to increase the loading capacity of the copper oxide clusters, and the samples are marked as NP-Au-CuO _X -3C。

Example 4

The preparation process is the same as that of example 2, and only differs from the following steps: the NP-Au sample is soaked in hydrazine hydrate solution and washed for 6 times, and then soaked in copper acetate solution at room temperature for 30min for washing, so that the loading capacity of the copper oxide cluster is increased, and the sample is marked as NP-Au-CuO _X -6C。

Example 5

NP-Au-CuO _X Application of electrode as electrocatalytic carbon dioxide material

NP-Au-CuO using the present invention _X Electrode KHCO at 0.1mol/L ₃ The electrochemical test is carried out on the electrocatalytic performance of the electrocatalytic carbon dioxide, and the application of the electrocatalytic carbon dioxide as an electrocatalytic carbon dioxide material is explored. By at N ₂ Aeration and CO ₂ Aerating KHCO at 0.1mol/L ₃ Middle NP-Au-CuO _X The Linear Sweep Voltammetry (LSV) curve shows for N ₂ The electrode only generates hydrogen evolution reaction in the aerated solution, and CO generates ₂ CO in aerated solution ₂ Reduction reactions will also be present (figure 4).

NP-Au-CuO _X Electrocatalytic reduction of CO by electrode material plasma resonance effect ₂ Comparison of Performance

Prepared NP-Au-CuO _X The electrode material is subjected to a constant potential electrochemical reduction carbon dioxide experiment under-0.97vs. RHE (-1.6V vs. Ag/AgCl), the electrolysis time is 1000s, and further discussion is given to the plasma harmonic effect on the electrocatalytic reduction of CO ₂ The influence of performance, experimental conditions, were divided into two, one was performed in the absence of light. Another xenon lamp with 300W is used as a light source to emphasize the light to 150mW/cm ² (simulating 1.5 times the intensity of sunlight). The light intensity irradiation experiment was performed (fig. 5).

NP-Au-CuO _X Reduction of CO by constant potential of electrode material ₂ Performance testing

Changing the electrolyte, CO, in the cell ₂ After saturation, the products at four different potentials were tested under both light and non-light conditions and CO, CH were detected by gas chromatography ₄ And (3) waiting for the gas products, detecting liquid products such as ethanol, formic acid and the like by using a nuclear magnetic resonance spectrometer, and calculating the Faraday conversion efficiency of the products according to a formula. A graph of faraday efficiency at different potentials was obtained (figure 6).

Claims

1. The preparation method of the nano mesoporous gold film loaded copper oxide cluster material is characterized by comprising the following steps:

s1, preparing a nano mesoporous gold film electrode: an Au/Ag double-layer film with the thickness of 5-10 nm Au/20nm Ag is deposited on the ITO substrate by adopting an electron beam evaporation technology, and heat treatment induction dehumidification treatment is carried out for 15min in an argon atmosphere at the temperature of 850-950 ℃; then soaking the dehumidified Au-Ag alloy particles into a nitric acid solution with the concentration of 60-70 wt% at 21 ℃ for 5min to remove Ag, and performing dealloying treatment to obtain the nano mesoporous gold film electrode;

s2, controllable loading of the copper oxide cluster: preparing 5-10 mM hydrazine hydrate solution and 1-10 mM copper acetate solution by using ultrapure water as a reducing agent and a copper precursor respectively: then soaking the nano mesoporous gold film electrode obtained in the step S1 in a hydrazine hydrate solution at room temperature for 20-30 min, adsorbing a reducing agent through a capillary effect, and then washing with deionized water to remove the redundant hydrazine hydrate solution on the surface; then, soaking the nano mesoporous gold film electrode absorbed with hydrazine hydrate in a copper acetate solution for 20-30 min at room temperature to ensure that Cu is in contact with the nano mesoporous gold film electrode ²⁺ Reducing, and washing with deionized water again;

s3, repeating the step S2 for 0-10 times; and (3) drying the membrane for 2 hours in vacuum at the temperature of between 90 and 100 ℃ by using a vacuum drying box to obtain the copper oxide cluster-loaded nano mesoporous gold membrane electrode.

2. The method of claim 1, wherein: step S1 is carried out by heat treating 5nm Au/20nm Ag Au/Ag bilayer film at 900 deg.C in argon atmosphere for 15min to induce dewetting, 65wt% ₃ And (4) removing alloy from the solution.

3. The method of claim 1, wherein in step S2, the reducing agent is hydrazine hydrate in 10mM and the copper precursor is copper acetate in 5mM, and the cyclic soaking time is 30min; the vacuum drying temperature is 100 ℃.

4. The application of the nano mesoporous gold film loaded copper oxide cluster material prepared by the method according to any one of claims 1 to 3 in the preparation of ethanol.