Ultra-thin hydrophobic silica layer coated metal or metal oxide nanocatalyst and applications

Abstract

The present application relates to a kind of ultra-thin hydrophobic silica layer coated metal or metal oxide nanocatalyst and application.The catalyst has hydrophobic shell-core structure, with metal or metal oxide nanoparticles as core, with ultra-thin hydrophobic silica as shell.The method includes the following steps: 1) metal or metal oxide nanoparticles are ultrasonically dispersed in silicon precursor solution;2) the powder obtained by centrifugation of solution in step 1) is solidified to obtain M(M X O Y ) / SiO2Catalyst, wherein M is the metal element in metal or metal oxide nanoparticles in step 1).The prepared catalyst shows excellent stability and high selectivity to CO2 reduction products in the process of electrocatalytic reduction of CO2 under acidic conditions.The M(M X O Y ) / SiO2Catalyst with hydrophobic shell-core structure is synthesized targetly, and the method is simple, and different metal monometallic, bimetallic or multi-metal catalysts coated with ultra-thin hydrophobic silica layer can be prepared on a large scale.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalysts, and particularly relates to a kind of ultra-thin hydrophobic silicon dioxide layer coated metal or metal oxide nanocatalyst and application. BACKGROUND

[0002] The conversion of carbon dioxide into high-value fuels and chemicals by renewable energy is one of the important ways to achieve carbon neutralization at present. High-performance catalysts are the key to achieving efficient electrocatalytic reduction of carbon dioxide, therefore, it is urgent to design and develop efficient catalysts for electrocatalytic reduction of carbon dioxide.

[0003] Metal or metal oxide nanoparticle catalysts, due to their nanoscale size, have high surface area, multiple active sites and high catalytic activity, and are widely used in the study of electrocatalytic reduction of carbon dioxide, such as Fe, Co, Ni, Cu, Zn, Mn, In, Sn, Sb, Bi, Au, Ag, Pd, Pb and Ir, etc. However, small-sized metal or metal oxide nanoparticles often agglomerate and deactivate due to their large surface energy during the reaction, affecting the catalytic performance. Studies have shown that introducing ligands or surfactants to modify metal or metal oxide nanoparticles or stabilizing metal or metal oxide nanoparticles on carriers can improve the stability and selectivity of metal or metal oxide nanoparticles in the catalytic process to varying degrees. However, most of the current research on metal or metal oxide nanoparticle catalysts is only suitable for neutral or alkaline electrolytes, which inevitably leads to the formation of carbonates and low carbon dioxide utilization efficiency during the reaction, which seriously hinders its large-scale commercial application. Therefore, the development of a catalyst for efficient electrocatalytic reduction of carbon dioxide under acidic conditions is the key to its large-scale application.

[0004] Silica is a high-stability, non-toxic and high-surface-area material, which is widely used in various fields due to its unique properties. In addition, due to the chemical inertness and high stability of silica, silica coating modification technology is often used to enhance the stability of materials. The Chinese patent with application number 201810832749.0 uses one-pot method to synthesize silica-coated Fe3O4 core-shell structure magnetic nanoparticles. FeCl2.4H2O is used as the precursor solution of iron and is added dropwise into the water-in-oil microemulsion to obtain Fe3O4 nanoparticle microemulsion. At this time, a silicon source such as tetraethyl orthosilicate (TEOS) is added, and then ammonia is added as a hydrolysis agent to induce TEOS to hydrolyze into silica on the surface of Fe3O4 nanoparticles. The obtained core-shell structure magnetic nanoparticles have uniform size, good dispersibility and are not easy to agglomerate. The Chinese patent with application number 202010009678.1 discloses a preparation method of silica-coated cobalt-based Fischer-Tropsch catalyst. Cobalt oxide particles / metal oxides are prepared by precipitation method and atomic deposition method, then are immersed in a solution containing silicon precursor and stirred uniformly, the solution is hydrothermally reacted at 80-250°C for 10-72 hours, and finally the product is dried and calcined to obtain a cobalt-based catalyst containing a silica shell. The prepared catalyst has ultra-high stability and can effectively inhibit the deactivation of the catalyst caused by sintering and water vapor oxidation. However, in the process of electrocatalytic reduction of carbon dioxide, the catalyst often accompanies dynamic spontaneous reconstruction, which reduces the hydrophobicity of the electrode surface and leads to performance degradation. In particular, the carbon dioxide electro-reduction reaction in an acidic electrolyte, the metal or metal oxide reacts with the acid, directly leading to catalyst deactivation. Encapsulating active nanoparticles in an inert silica shell with hydrophobic properties is an effective strategy to maintain the stability of its catalytic performance. However, since silica is an insulating material, as a shell layer of catalyst, it needs to have a stable ultra-thin thickness to ensure its catalytic activity. Therefore, developing an efficient preparation method of stable ultra-thin hydrophobic silica shell is the key to realize its large-scale application. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of existing metal or metal oxide nanoparticle catalysts in the electro-reduction of carbon dioxide under acidic conditions, and to provide a metal or metal oxide nanoparticle catalyst coated with an ultra-thin hydrophobic silica layer and its application. The catalyst is a metal or metal oxide nanoparticle catalyst coated with an ultra-thin hydrophobic silica layer. In the catalyst, the silica coating thickness is controllable, the active metal or metal oxide nanoparticle is the core, and the ultra-thin inert silica with hydrophobic properties is the shell, which are assembled together into a core-shell catalyst M(M X O Y) / SiO2, wherein M is a metal element selected from one, two or more of Fe, Co, Ni, Cu, Zn, Mn, In, Sn, Sb, Bi, Au, Ag, Pd, Pb and Ir.

[0006] The object of the present application is achieved by the following technical solutions:

[0007] A metal or metal oxide nanocatalyst coated with an ultrathin hydrophobic silica layer, the catalyst having a hydrophobic shell-core structure, with metal or metal oxide nanoparticles as the core and ultrathin hydrophobic silica as the shell; the mass percentage of the metal or metal oxide nanoparticles is 80wt% to 99wt% based on the total mass of the catalyst; preferably, the mass percentage of the metal or metal oxide nanoparticles is 95wt% to 99wt%; preferably, the mass percentage of the metal or metal oxide nanoparticles is 98wt% to 99wt%. For example, the mass percentage of the metal or metal oxide nanoparticles is 80wt%, 81wt%, 82wt%, 83wt%, 84wt%, 85wt%, 86wt%, 87wt%, 88wt%, 89wt%, 90wt%, 91wt%, 92wt%, 93wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt% or 99wt% based on the total mass of the catalyst. Preferably, the balance is ultrathin hydrophobic silica.

[0008] In the present application, ultrathin hydrophobic refers to the thickness of the silica shell layer in the metal or metal oxide nanoparticle catalyst coated with an ultrathin hydrophobic silica layer, which is only 2 to 10 nm.

[0009] Further, the catalyst is composed of hydrophobic silica and metal oxide nanoparticles.

[0010] Further, the metal element in the metal or metal oxide nanoparticles is selected from one, two or more of Fe, Co, Ni, Cu, Zn, Mn, In, Sn, Sb, Bi, Au, Ag, Pd, Pb and Ir.

[0011] Further, the metal or metal oxide nanoparticles have a particle size of 50-200 nm, for example, the metal or metal oxide nanoparticles have a particle size of 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm, 150 nm, 155 nm, 160 nm, 165 nm, 170 nm, 175 nm, 180 nm, 185 nm, 190 nm, 195 nm or 200 nm. Preferably, the metal or metal oxide nanoparticles have a particle size of 100 nm.

[0012] Further, the metal or metal oxide nanoparticles are coated with an ultrathin hydrophobic silica layer, and the silica shell has a thickness of 2-10 nm, for example, the silica shell has a thickness of 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm or 10 nm. Preferably, the silica shell has a thickness of 4 nm, and the water contact angle of the catalyst is 142°.

[0013] A method for preparing the catalyst as described above, comprising the following steps:

[0014] 1) ultrasonic dispersion of metal or metal oxide nanoparticles in a silicon precursor solution, and standing of the solution for 30-50 min; wherein the metal element in the metal or metal oxide nanoparticles is selected from one, two or more of Fe, Co, Ni, Cu, Zn, Mn, In, Sn, Sb, Bi, Au, Ag, Pd, Pb and Ir; preferably, when the metal or metal oxide nanoparticles are ultrasonically dispersed in the silicon precursor solution, the silicon precursor spontaneously adheres to the surface of the metal or metal oxide nanoparticles;

[0015] 2) centrifugation of the solution in step 1), and vacuum drying of the obtained powder in a vacuum drying oven at a constant temperature of 60-70 °C for 1-1.5 h, and then standing of the powder at room temperature for 12-15 h to obtain an M(M X O Y ) / SiO2 catalyst, wherein M is the metal element in the metal or metal oxide nanoparticles in step 1).

[0016] In particular, a method for preparing the catalyst as described above, comprising the following steps:

[0017] 1) ultrasonic dispersion of metal or metal oxide nanoparticles in a silicon precursor solution, the solution is left to stand for 30 min; wherein the metal element in the metal or metal oxide nanoparticles is selected from one, two or more of Fe, Co, Ni, Cu, Zn, Mn, In, Sn, Sb, Bi, Au, Ag, Pd, Pb and Ir;

[0018] 2) centrifugation of the solution in step 1) at 10000 rmp for 60 min, the powder obtained by centrifugation is heated at 60℃ in a vacuum drying oven for 1 h and then left to stand at room temperature for 12 h to obtain a M(M X O Y ) / SiO2 catalyst, wherein M is the metal element in the metal or metal oxide nanoparticles in step 1).

[0019] Further, the silicon precursor in step 1) comprises one or both of organic polysilazane and inorganic polysilazane.

[0020] Further, the solvent in the silicon precursor solution in step 1) is one or more of acetone, methyl ethyl ketone, n-butyl ether, toluene, cyclohexane, methylcyclohexane, xylene, butyl acetate and ethyl acetate, preferably butyl acetate or ethyl acetate.

[0021] Further, in step 1), the mass concentration of the silicon precursor solution is 1% to 0.01%, preferably the mass concentration of the silicon precursor solution is 0.01%.

[0022] Further, the addition amount of the silicon precursor solution and the metal or metal oxide nanoparticles in step 1) is 50-100 parts by weight of the silicon precursor solution and 1-20 parts by weight of the metal or metal oxide nanoparticles.

[0023] Further, the addition amount of the silicon precursor solution and the metal or metal oxide nanoparticles in step 1) is 50-100 parts by weight of the silicon precursor solution and 5-20 parts by weight of the metal or metal oxide nanoparticles.

[0024] The catalyst as described in any one of the above or prepared by the method as described in any one of the above is applied in electrocatalysis of carbon dioxide.

[0025] The present application has the following advantages:

[0026] 1) The preparation method of the ultra-thin hydrophobic silicon dioxide layer coated metal or metal oxide nanoparticle catalyst provided by the present application is simple and efficient, avoiding the characteristics of traditional methods which are complex and have many steps. The method only needs to immerse the metal or metal oxide nanoparticles in a silicon precursor solution, the silicon precursor spontaneously adheres to the surface of the metal or metal oxide nanoparticles, and then further air curing treatment is performed to obtain a M(M X OY 1) The Cu / SiO2 core-shell structure catalyst is prepared by a simple and environmentally friendly method, and can be prepared on a large scale. 2) The ultra-thin hydrophobic shell layer of the catalyst is made of silicon dioxide, which has the characteristics of stability, corrosion resistance, oxidation resistance and hydrophobicity, and the thickness of the silicon dioxide can be controlled by the precursor solution. By controlling the thickness of the silicon dioxide shell layer to several nanometers, the stability of the metal or metal oxide nanoparticle structure can be ensured. 3) M(M X O Y ) / SiO2 M can be effectively controlled by adding metal or metal oxide nanoparticles, and catalysts of different metals, single metals, double metals, multiple metals or metal oxides can be prepared. 5) The prepared M(M X O Y ) / SiO2 carbon dioxide reduction catalyst exhibits excellent stability and high selectivity for CO2 reduction products under acidic conditions. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 Scanning electron micrographs of Cu nanoparticles (a) and Cu / SiO2 catalyst (b) of the present application;

[0028] Figure 2 Transmission electron micrographs (a) and element distribution (b) spectra of Cu / SiO2 catalyst of the present application;

[0029] Figure 3 Static contact angle test diagram of Cu nanoparticles (a) and Cu / SiO2 catalyst (b) of the present application; Figure 3 Figure 3

[0030] Figure 4 Electrocatalytic reduction of carbon dioxide performance diagram of Cu / SiO2 catalyst of the present application;

[0031] Figure 5 Stability of Cu / SiO2 catalyst for electrocatalytic reduction of carbon dioxide of the present application. DETAILED DESCRIPTION

[0032] The present application will be described in detail below with reference to the accompanying drawings and specific examples. However, the following examples are only intended to explain the present application, and the scope of protection of the present application should include all the contents of the claims. Furthermore, through the description of the following examples, those skilled in the art can fully realize the entire contents of the claims of the present application.

[0033] Example 1:

[0034] The preparation method of Cu / SiO2 includes the following steps: ​​

[0035] 1) 100 μL of organic polysilazane IOTA9283 (purity 10%, manufacturer: Anhui Aiyouta Silicone Oil Co., Ltd.) and 100 mL of butyl acetate (purity 99.5%, manufacturer: Macklin) were mixed uniformly to obtain a silicon precursor solution with a mass concentration of 0.01%, and then 1 g of Cu nanoparticles (100 nm) was mixed uniformly with 100 mL of the prepared silicon precursor solution (mass concentration 0.01%) to obtain a uniform dispersion solution. The solution was allowed to stand for 30 min.

[0036] 2) The solution in step 1) was centrifuged at a speed of 10000 rmp for 60 min, and the powder obtained by centrifugation was heated at a constant temperature of 60°C in a vacuum drying oven for 1 h, and finally placed at room temperature for 12 h to obtain a Cu / SiO2 catalyst.

[0037] Figure 1 Figure (a) is a scanning electron microscope image of Cu nanoparticles of the application.

[0038] Figure 1 Figure (b) is a scanning electron microscope image of the Cu / SiO2 catalyst prepared in Example 1, and the particle size of the catalyst is about 100 nm.

[0039] Figure 2 Figure is a transmission electron microscope image (a) and element distribution spectrum (b) of the Cu / SiO2 catalyst prepared in Example 1, and the results show that the prepared Cu / SiO2 catalyst has a core-shell structure, and the thickness of the SiO2 shell layer is about 4 nm.

[0040] Figure 3 Figure is a transmission electron microscope image (a) and element distribution spectrum (b) of the Cu / SiO2 catalyst prepared in Example 1, Figure 3 and Cu nanoparticles, Figure 3 Figure is a static contact angle test diagram of the Cu / SiO2 catalyst prepared in Example 1 (b) and Cu nanoparticles (a), and the results show that after coating with an ultrathin hydrophobic SiO2 shell layer, the Cu / SiO2 catalyst exhibits hydrophobicity, and the water contact angle is 142°.

[0041] Figure 4 Figure is a performance diagram of the electrocatalytic reduction of carbon dioxide of the Cu / SiO2 catalyst prepared in Example 1, and the results show that the Cu / SiO2 catalyst can electrocatalytically convert CO2 into high-value-added C 2+ products such as ethylene, ethanol and acetic acid, and the faradic efficiency of the C 2+ products reaches 69.8%;

[0042] Example 2:

[0043] The preparation method of Ag / SiO2 comprises the following steps:

[0044] 1) 100 μL of organic polysilazane IOTA9283 (purity 10%, manufacturer: Anhui Aiyouta Silicone Oil Co., Ltd.) and 100 mL of butyl acetate (purity 99.5%, manufacturer: Macklin) were mixed uniformly to obtain a silicon precursor solution with a mass concentration of 0.01%, and then 1 g of Ag nanoparticles (100 nm) was uniformly mixed with 100 mL of the prepared silicon precursor solution (mass concentration of 0.01%) to obtain a uniform dispersion, and the solution was allowed to stand for 30 min.

[0045] 2) The solution in step 1) was centrifuged at a speed of 10000 rmp for 60 min, and the powder obtained by centrifugation was heated at a constant temperature of 60°C in a vacuum drying oven for 1 h, and finally placed at room temperature for 12 h to obtain the Ag / SiO2 catalyst. The prepared Ag / SiO2 catalyst showed hydrophobicity.

[0046] Example 3:

[0047] The preparation method of Sn / SiO2 includes the following steps:

[0048] 1) 100 μL of organic polysilazane IOTA9283 (purity 10%, manufacturer: Anhui Aiyouta Silicone Oil Co., Ltd.) and 100 mL of butyl acetate (purity 99.5%, manufacturer: Macklin) were mixed uniformly to obtain a silicon precursor solution with a mass concentration of 0.01%, and then 1 g of Sn nanoparticles (100 nm) was uniformly mixed with 100 mL of the prepared silicon precursor solution (mass concentration of 0.01%) to obtain a uniform dispersion, and the solution was allowed to stand for 30 min.

[0049] 2) The solution in step 1) was centrifuged at a speed of 10000 rmp for 60 min, and the powder obtained by centrifugation was heated at a constant temperature of 60°C in a vacuum drying oven for 1 h, and finally placed at room temperature for 12 h to obtain the Sn / SiO2 catalyst. The prepared Sn / SiO2 catalyst showed hydrophobicity.

[0050] Example 4:

[0051] The preparation method of Ni / SiO2 includes the following steps:

[0052] 1) 100 μL of organic polysilazane IOTA9283 (purity 10%, manufacturer: Anhui Aiyouta Silicone Oil Co., Ltd.) and 100 mL of butyl acetate (purity 99.5%, manufacturer: Macklin) were mixed uniformly to obtain a silicon precursor solution with a mass concentration of 0.01%, and then 1 g of Ni nanoparticles (100 nm) was uniformly mixed with 100 mL of the prepared silicon precursor solution (mass concentration of 0.01%) to obtain a uniform dispersion, and the solution was allowed to stand for 30 min.

[0053] 2) The solution in step 1) is centrifuged at 10000 rpm for 60 min, and the powder obtained by centrifugation is heated at 60°C in a vacuum drying oven for 1 h, and then placed at room temperature for 12 h to obtain the Ni / SiO2 catalyst. The prepared Ni / SiO2 catalyst exhibits hydrophobicity.

[0054] The prepared Cu / SiO2 catalyst electrocatalytically reduces carbon dioxide into C 2+ products in an acidic medium.

[0055] The Cu / SiO2 catalyst prepared in Example 1 electrocatalytically reduces carbon dioxide into C 2+ products in an acidic medium, and the types of the generated products and the corresponding Faraday efficiencies are tested. The testing method comprises the following steps:

[0056] The Faraday efficiency measurement testing device is a CHI-760E electrochemical workstation from Shanghai Chenhua Instrument Co., Ltd. The testing conditions are as follows: a flow cell electrochemical reactor under a three-electrode system, the prepared Cu / SiO2 catalyst as a cathode, a platinum sheet as an anode, a saturated Ag / AgCl electrode as a reference electrode, a CO2 reaction cavity volume of 1 mL, 0.005 M H2SO4 and 0.5 M K2SO4 as an electrolyte, a gas pressure of 1 atmosphere, a temperature of room temperature, a CO2 flow rate of 20 cc / min, an electrode area of 1 cm 2 , and a catalyst loading on the electrode of 1 mg / cm 2 . The chronoamperometry test is performed at 350 mAcm -2 . The products after CO2 reduction are analyzed by gas chromatography and nuclear magnetic resonance. The gas chromatography is performed by using a GC-2014 device from Japan SHIMADZU Co., Ltd., and the nuclear magnetic resonance is performed by using an AV-400 device from Germany Bruker Co. The testing results are shown in Figures 4-5 . The Cu / SiO2 electrocatalytically reduces carbon dioxide into high-value-added C 2+ products such as ethylene, ethanol and acetic acid in 0.005 M H2SO4. The Faraday efficiency of the C 2+ products is as high as 69.8%, and the Cu / SiO2 catalyst has good stability and can be applied commercially. The stability test of the Cu / SiO2 catalyst prepared in Example 1 for electrocatalytic reduction of carbon dioxide is performed at a current density of 200 mAcm -2 . The testing results are shown in Figure 5 . Figure 5 The stability of the Cu / SiO2 catalyst prepared in Example 1 for electrocatalytic reduction of carbon dioxide can be seen from Figure 5 . In the flow cell, the Cu / SiO2 catalyst can be stably catalyzed at a current density of 200 mAcm -2 for 16.5 h without obvious attenuation.

[0057] Using the same test method as in Example 1, the Ag / SiO2 catalyst prepared in Example 2 electrocatalyzed the reduction of carbon dioxide to CO in an acidic medium, with a CO product Faraday efficiency of up to 93.3%, and was able to stably catalyze for 8h at a current density of 200mAcm -2 , without significant decay.

[0058] Using the same test method as in Example 1, the Sn / SiO2 catalyst prepared in Example 3 electrocatalyzed the reduction of carbon dioxide to formic acid in an acidic medium, with a formic acid product Faraday efficiency of up to 90.3%, and was able to stably catalyze for 10h at a current density of 200mAcm -2 , without significant decay.

[0059] Using the same test method as in Example 1, the Ni / SiO2 catalyst prepared in Example 4 electrocatalyzed the reduction of carbon dioxide to CO in an acidic medium, with a CO product Faraday efficiency of up to 84.6%, and was able to stably catalyze for 7h at a current density of 200mAcm -2 , without significant decay.

[0060] It should be noted that, according to the above embodiments of the present application, a person skilled in the art can fully realize the entire scope of the independent claim and the dependent claims of the present application, and the implementation process and method are the same as the above embodiments; and the part not described in detail in the present application belongs to the commonly known technology in the art.

[0061] The above is only part of the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. An ultra-thin hydrophobic silica layer coated metal or metal oxide nano-catalyst, characterized in that, The catalyst has a hydrophobic shell core structure, with metal or metal oxide nanoparticles as the core and ultra-thin hydrophobic silicon dioxide as the shell; the mass percentage of the metal or metal oxide nanoparticles is 80 wt% to 99 wt% based on the total mass of the catalyst; the thickness of the silicon dioxide shell layer is 2 to 9 nm; the catalyst is prepared by a method comprising the following steps: 1) ultrasonic dispersion of metal or metal oxide nanoparticles in a silicon precursor solution, and standing of the solution for 30 to 50 min; wherein the metal element in the metal or metal oxide nanoparticles is selected from one, two or more of Fe, Co, Ni, Cu, Zn, Mn, In, Sn, Sb, Bi, Au, Ag, Pd, Pb and Ir; when the metal or metal oxide nanoparticles are ultrasonically dispersed in the silicon precursor solution, the silicon precursor spontaneously adheres to the surface of the metal or metal oxide nanoparticles; wherein the silicon precursor is an organic polysilazane; the solvent in the silicon precursor solution is selected from one or more of acetone, methyl ethyl ketone, n-butyl ether, toluene, cyclohexane, methylcyclohexane, xylene, butyl acetate and ethyl acetate; the mass concentration of the silicon precursor solution is 1% to 0.01%; the addition amount of the silicon precursor solution and the metal or metal oxide nanoparticles is 50 to 100 parts by weight of the silicon precursor solution and 1 to 20 parts by weight of the metal or metal oxide nanoparticles; 2) centrifugation of the solution in step 1), and constant temperature heating of the powder obtained by centrifugation in a vacuum drying oven at 60°C to 70°C for 1 to 1.5 h, followed by normal temperature standing for 12 to 1 h, to obtain a metal or metal oxide nanoparticle catalyst coated with an ultra-thin hydrophobic silicon dioxide layer.

2. The catalyst according to claim 1, characterized in that, The mass percentage of the metal or metal oxide nanoparticles is 95 wt% to 99 wt%.

3. The catalyst of claim 1, wherein The mass percentage of the metal or metal oxide nanoparticles is 98 wt% to 99 wt%.

4. The catalyst of claim 1, wherein The particle size of the metal or metal oxide nanoparticles is 50 to 200 nm.

5. The catalyst of claim 1, wherein The particle size of the metal or metal oxide nanoparticles is 100 nm.

6. The catalyst of claim 1, wherein The thickness of the silicon dioxide shell layer is 4 nm, and the water contact angle thereof is 142º.

7. The catalyst of claim 1, wherein The addition amount of the silicon precursor solution and the metal or metal oxide nanoparticles in step 1) is 50 to 100 parts by weight of the silicon precursor solution and 5 to 20 parts by weight of the metal or metal oxide nanoparticles.

8. Use of the catalyst of claim 1 in electrocatalytic reduction of carbon dioxide.

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