Photocathodes and their preparation methods and applications, electrolytic cells and preparation methods of higher alcohol organic compounds

Abstract

This invention relates to the field of high-carbon alcohol organic compounds, and discloses a photocathode, its preparation method and application, an electrolytic cell, and a method for preparing high-carbon alcohol organic compounds. The photocathode uses a silicon nanowire array electrode sheet as a substrate. On the surface of the substrate, a connecting layer, an aldehyde-modified layer, and a covalent triazine framework metal complex material modification layer are sequentially coated from the inside out. The weight ratio of the substrate, connecting layer, aldehyde-modified layer, and covalent triazine framework metal complex material modification layer is 1:(0.01-0.03):(0.02-0.06):(0.06-0.18). The photocathode provided by this invention has the ability to adsorb carbon dioxide, improves the selectivity of high-carbon alcohol organic compounds, and enhances the carbon dioxide reduction capacity. The preparation method simplifies the operating conditions and process flow, facilitating industrial production. Using the photocathode provided by this invention to prepare high-carbon alcohol organic compounds exhibits excellent carbon dioxide adsorption performance, high selectivity, and high product yield.

Description

Technical Field

[0001] This invention relates to the field of higher alcohol organics, specifically to a photocathode and its preparation method and application, an electrolytic cell, and a method for preparing higher alcohol organics. Background Technology

[0002] With the rapid development of industrialization and modernization, carbon dioxide (CO2) emissions have increased year by year. As the most significant component of greenhouse gases, CO2 has caused global warming and frequent extreme weather events, seriously affecting people's lives. Solar energy, as a widely distributed, abundant, environmentally friendly, green, and sustainable energy source, has received attention from countries around the world. Utilizing solar energy as a driving force to convert CO2 and water into organic matter is a long-awaited green chemical technology and an essential technology for achieving the ambitious goal of carbon neutrality. Currently, research on the catalytic reduction of carbon dioxide in water mainly focuses on electrocatalysis, photocatalysis, and combined photoelectrocatalysis methods. The reduction products are mainly small-molecule organic compounds such as formic acid, carbon monoxide, and methane. Most of the reported products have poor selectivity and low yield, posing certain difficulties for application in actual industrial production.

[0003] CN106757136A discloses a method for preparing methanol from carbon dioxide and water. This method can directly obtain methanol from water and carbon dioxide under light conditions with high selectivity. However, its application prospects are limited by the poor conductivity, fragility, heavy weight and high price of FTO glass electrodes.

[0004] CN105332002A discloses a method for preparing ethanol from carbon dioxide and water. This method can directly obtain ethanol from water and carbon dioxide under light conditions with high selectivity. However, its application prospects are limited by the poor conductivity, fragility, heavy weight and high price of FTO glass electrodes.

[0005] CN109234758A discloses a method for preparing long-chain oxygen-containing compounds using carbon dioxide and water. This method can prepare long-chain oxygen-containing compounds with a carbon content of approximately C2. 50 -C 300 The process of producing a series of downstream products through cracking, which are converted into various high-value-added chemicals such as alkanes, olefins, gasoline and diesel, is of great significance. However, the reported product structures are unclear.

[0006] Therefore, there is an urgent need to develop new photocathodes for use in high carbon alcohol organic compounds. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of poor carbon dioxide adsorption performance, poor organic matter selectivity, and low product yield in the photoelectrocatalytic preparation of higher alcohols in the prior art, and to provide a photocathode and its preparation method and application, an electrolytic cell, and a method for preparing higher alcohol organic matter.

[0008] To achieve the above objectives, the first aspect of the present invention provides a photocathode, wherein the photocathode uses a silicon nanowire array electrode sheet as a substrate, and on the surface of the substrate, a connecting layer, an aldehyde-based modification layer, and a covalent triazine framework metal complex material modification layer are sequentially coated from the inside to the outside.

[0009] The weight ratio of the matrix, the connecting layer, the aldehyde-modified layer and the covalent triazine framework metal complex material modification layer is 1:(0.01-0.03):(0.02-0.06):(0.06-0.18).

[0010] A second aspect of the present invention provides a method for preparing a photocathode, wherein the method includes the following steps:

[0011] 1) The electrode sheet of the silicon nanowire array is placed in a first mixed solution containing silane coupling agent and anhydrous ethanol, and subjected to a first heating and reflux to obtain electrode sheet I;

[0012] 2) The above electrode sheet I is placed in a second mixed solution containing aldehyde organic matter and the first solvent, and then subjected to a second heating and reflux to obtain an aldehyde-modified electrode sheet;

[0013] 3) The third mixed solution containing 1,4-terephthalamide hydrochloride, carbonate and the second solvent is mixed with the second mixed solution and subjected to a third heating and reflux and washing to obtain an electrode sheet modified with a covalent triazine framework material;

[0014] 4) The electrode sheet modified with the above covalent triazine framework material is placed in a metal salt solution and dried to obtain a photocathode.

[0015] A third aspect of the present invention provides the application of the above-described photocathode in the preparation of higher alcohol organic compounds.

[0016] A fourth aspect of the present invention provides an electrolytic cell, wherein the electrolytic cell comprises a photocathode of the present invention or a photocathode prepared by the preparation method of the present invention; the electrolytic cell is used for the preparation of higher alcohol organic compounds;

[0017] Preferably, the electrolytic cell further includes a photoanode, which is selected from any one of BiVO4 / Ni, BiVO4 / Cu, BiVO4 / Al, and BiVO4 / Ti;

[0018] Preferably, the electrolytic cell further includes an electrolyte, wherein the electrode solution is an inorganic salt solution selected from aqueous solutions of KHCO3 and / or NaHCO3;

[0019] Preferably, the concentration of the inorganic salt solution is 0.05-0.3 mol / L.

[0020] A fifth aspect of the present invention provides a method for preparing higher alcohol organic compounds, wherein the method comprises:

[0021] Under illumination, CO2 is introduced into an electrolytic cell to react and obtain higher carbon alcohol organic compounds; wherein, the electrolytic cell is the electrolytic cell described in the fourth aspect;

[0022] Preferably, in the reaction, the voltage between the photocathode and photoanode in the electrolytic cell is 0.4-1.8V.

[0023] Through the above technical solutions, the photocathode, its preparation method and application, electrolytic cell, and preparation method of higher alcohol organic compounds provided by the present invention achieve the following beneficial effects:

[0024] (1) The photocathode provided by the present invention uses a silicon nanowire array electrode sheet as the substrate. The photocathode uses a silicon nanowire array electrode sheet as the substrate. The surface of the substrate is coated with a connecting layer, an aldehyde modification layer, and a covalent triazine framework metal complex material modification layer from the inside to the outside, so that the photocathode has the ability to adsorb carbon dioxide and improves the selectivity of high carbon alcohol organic compounds and the ability to reduce carbon dioxide.

[0025] (2) The method for preparing the photocathode provided by the present invention simplifies the operating conditions and process flow, and facilitates industrial production;

[0026] (3) The photocathode provided by the present invention is used to prepare high carbon alcohol organic compounds, which has excellent carbon dioxide adsorption performance, high selectivity and product yield. Attached Figure Description

[0027] Figure 1 The above is the 1H NMR spectrum of the mixture mainly composed of higher alcohols in Test Example 1 of this invention;

[0028] Figure 2 The image shows the TOF mass spectrum of tridecyl alcohol in Test Example 1 of this invention. Detailed Implementation

[0029] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0030] The first aspect of the present invention provides a photocathode, wherein the photocathode is based on an electrode sheet of a silicon nanowire array, and on the surface of the substrate, a connecting layer, an aldehyde-based modification layer, and a covalent triazine framework metal complex material modification layer are sequentially coated from the inside to the outside.

[0031] The weight ratio of the matrix, the connecting layer, the aldehyde-modified layer and the covalent triazine framework metal complex material modification layer is 1:(0.01-0.03):(0.02-0.06):(0.06-0.18).

[0032] In this invention, the photocathode has advantages such as the ability to adsorb carbon dioxide, improved selectivity of higher alcohol organic compounds, and improved carbon dioxide reduction capacity.

[0033] In this invention, when the weight ratio of the matrix, the connecting layer, the aldehyde-modified layer and the covalent triazine framework metal complex material modification layer does not meet the above range, the catalytic performance of the photocathode is reduced.

[0034] According to the present invention, the compound constituting the connecting layer is a silane coupling agent, wherein the silane coupling agent is selected from at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-aminoethyl-aminopropyltrimethoxysilane and 3-[2-[2-aminoethylamino]-ethylamino]-propyl-aminotrimethoxysilane.

[0035] According to the present invention, the compound constituting the aldehyde-modified layer is selected from at least one of 1,4-terephthalaldehyde, biphenyl dicarboxaldehyde, bipyridine dicarboxaldehyde, binaphthalene dicarboxaldehyde, and biquinoline dicarboxaldehyde.

[0036] According to the present invention, the material constituting the covalent triazine framework metal complex material modification layer comprises a covalent triazine framework and a metal complex, wherein the covalent triazine framework is a product of the reaction of an aldehyde organic compound with 1,4-terephthalamide hydrochloride; wherein the aldehyde organic compound is selected from at least one of 1,4-terephthalaldehyde, biphenyl dicarboxaldehyde, bipyridine dicarboxaldehyde, binaphthalene dicarboxaldehyde, and biquinoline dicarboxaldehyde; and the metal complex is selected from at least one of Cu(NO3)2, Co(NO3)2, Ni(NO3)2, Pd(NO3)2, and HAuCl4.

[0037] A second aspect of the present invention provides a method for preparing a photocathode, wherein the method includes the following steps:

[0038] 1) The electrode sheet of the silicon nanowire array is placed in a first mixed solution containing silane coupling agent and anhydrous ethanol, and subjected to a first heating and reflux to obtain electrode sheet I;

[0039] 2) The above electrode sheet I is placed in a second mixed solution containing aldehyde organic matter and the first solvent, and then subjected to a second heating and reflux to obtain an aldehyde-modified electrode sheet;

[0040] 3) The third mixed solution containing 1,4-terephthalamide hydrochloride, carbonate and the second solvent is mixed with the second mixed solution and subjected to a third heating and reflux and washing to obtain an electrode sheet modified with a covalent triazine framework material;

[0041] 4) The electrode sheet modified with the above covalent triazine framework material is placed in a metal salt solution and dried to obtain a photocathode.

[0042] In this invention, the covalent triazine framework material is a type of crystalline porous solid organic material with characteristics such as high specific surface area, tailorability, functionalizability, and multiple active sites. Using this material can reduce light reflection in the photocathode and increase the absorption capacity of carbon dioxide, thereby improving the photocathode's reduction efficiency of carbon dioxide and selectivity for higher carbon alcohol organic compounds.

[0043] According to the present invention, in step 1), the conditions for the first heating reflux include: a temperature of 60-80°C and a time of 2-10 hours.

[0044] According to the present invention, in step 2), the first solvent is selected from at least one of dimethyl sulfoxide, N,N-dimethylformamide and tetrahydrofuran.

[0045] According to the present invention, in step 2), the molar volume ratio of the aldehyde organic compound to the first solvent is 1 mmol: (40-80) mL.

[0046] According to the present invention, in step 2), the conditions for the second heating reflux include: a temperature of 60-80°C and a time of 2-10 hours.

[0047] According to the present invention, in step 3), the molar volume ratio of the 1,4-terephthalamide hydrochloride, the carbonate, and the second solvent is 1 mmol: (2-8) mmol: (20-80) mL.

[0048] According to the present invention, in step 3), the carbonate is selected from at least one of cesium carbonate, potassium carbonate and strontium carbonate.

[0049] According to the present invention, in step 3), the conditions for the third heating reflux include: a temperature of 80-120°C and a time of 4-20 hours.

[0050] According to the present invention, in step 4), the metal salt solution is selected from at least one aqueous solution of Cu(NO3)2, Co(NO3)2, Ni(NO3)2, Pd(NO3)2 and HAuCl4.

[0051] According to the present invention, in step 4), the concentration of the metal salt solution is 0.05-0.5M.

[0052] According to the present invention, in step 4), the drying conditions include: a temperature of 60-80°C and a time of 4-20 hours.

[0053] A third aspect of the present invention provides the application of the above-described photocathode in the preparation of higher alcohol organic compounds.

[0054] A fourth aspect of the present invention provides an electrolytic cell, wherein the electrolytic cell comprises a photocathode of the present invention or a photocathode prepared by the preparation method of the present invention; the electrolytic cell is used for the preparation of higher alcohol organic compounds;

[0055] Preferably, the electrolytic cell further includes a photoanode, which is selected from any one of BiVO4 / Ni, BiVO4 / Cu, BiVO4 / Al, and BiVO4 / Ti;

[0056] Preferably, the electrolytic cell further includes an electrolyte, wherein the electrode solution is an inorganic salt solution selected from aqueous solutions of KHCO3 and / or NaHCO3;

[0057] Preferably, the concentration of the inorganic salt solution is 0.05-0.3 mol / L.

[0058] In this invention, the photoanode is prepared using a three-electrode system: reference electrode: Ag / AgCl; counter electrode: Pt wire; working electrode: nickel foam, copper foam, aluminum foam, or titanium foam. Electrolysis is performed for 100-300 seconds under a bias voltage of 0.1V. After rinsing with deionized water and drying, an orange-red BiOI / Ni, BiOI / Cu, BiOI / Al, or BiOI / Ti electrode is obtained. 850 mg of NH4VO3 is dissolved in 250 mL of deionized water and transferred to a hydrothermal reactor. The synthesized BiOI / Ni, BiOI / Cu, BiOI / Al, or BiOI / Ti electrode is placed in the reactor and reacted hydrothermally at 120°C for 12 hours. After cooling to room temperature, it is soaked in 1M NaOH for 10 minutes to obtain a usable BiVO4 / Ni, BiVO4 / Cu, BiVO4 / Al, or BiVO4 / Ti photoanode.

[0059] According to the present invention, the electrolytic cell is divided into an anode chamber and a cathode chamber by a proton exchange membrane.

[0060] According to the present invention, the electrolyte in the anode chamber further includes organic dyes.

[0061] Furthermore, the organic dye is selected from at least one of eosin Y, methylene blue, Nile red, and methyl violet.

[0062] In this invention, the concentration of the organic dye is 1-3 mM.

[0063] A fifth aspect of the present invention provides a method for preparing higher alcohol organic compounds, wherein the method comprises:

[0064] Under illumination, CO2 is introduced into an electrolytic cell to react and obtain higher carbon alcohol organic compounds; wherein, the electrolytic cell is the electrolytic cell of the present invention;

[0065] Preferably, in the reaction, the voltage between the photocathode and photoanode in the electrolytic cell is 0.4-1.8V.

[0066] The present invention will be described in detail below through embodiments. In the following embodiments,

[0067] All raw materials used in the examples and comparative examples are commercially available products.

[0068] Example 1

[0069] 1) Place 40 cm 2 The electrode sheet of the silicon nanowire array was placed in a mixed solution of 3-aminopropyltriethoxysilane and anhydrous ethanol and refluxed at 70°C for 6 hours to obtain electrode sheet I.

[0070] 2) Electrode I was placed in a mixed solution of 1,4-terephthalaldehyde and dimethyl sulfoxide and refluxed at 70°C for 6 h to obtain an aldehyde-modified electrode, wherein the molar volume ratio of 1,4-terephthalaldehyde to the first solvent was 1 mmol: 60 mL.

[0071] 3) A mixed solution of 1,4-terephthalamide hydrochloride, cesium carbonate and dimethyl sulfoxide was added to the above mixed solution of 1,4-terephthalaldehyde and dimethyl sulfoxide, and refluxed at 100°C for 12 h. After washing, an electrode sheet modified with a covalent triazine framework material was obtained, wherein the molar volume ratio of 1,4-terephthalamide hydrochloride, cesium carbonate and dimethyl sulfoxide was 1 mmol: 5 mmol: 50 mL.

[0072] 4) The electrode sheet modified with the above covalent triazine framework material was immersed in 0.3M Cu(NO3)2 solution for 4h and vacuum dried at 60℃ for 12h to obtain photocathode A1, wherein the weight ratio of the substrate, the connecting layer, the aldehyde-based modification layer and the covalent triazine framework metal complex material modification layer is 1:0.02:0.04:0.12.

[0073] Example 2

[0074] 1) Place 40 cm 2 The electrode sheet of the silicon nanowire array was placed in a mixed solution of 3-aminopropyltrimethoxysilane and anhydrous ethanol and refluxed at 65°C for 8 hours to obtain electrode sheet I.

[0075] 2) Electrode I was placed in a mixed solution of biphenyl dicarboxaldehyde and N,N-dimethylformamide and refluxed at 65°C for 8 h to obtain an aldehyde-modified electrode, wherein the molar volume ratio of biphenyl dicarboxaldehyde and N,N-dimethylformamide was 1 mmol: 50 mL.

[0076] 3) A mixed solution of 1,4-terephthalamide hydrochloride, potassium carbonate and N,N-dimethylformamide was added to the mixed solution of biphenyl dicarboxaldehyde and N,N-dimethylformamide. The mixture was refluxed at 90°C for 16 h and washed to obtain an electrode sheet modified with a covalent triazine framework material. The molar volume ratio of 1,4-terephthalamide hydrochloride, potassium carbonate and N,N-dimethylformamide was 1 mmol:3 mmol:30 mL.

[0077] 4) The electrode sheet modified with the above covalent triazine framework material was immersed in 0.15M Co(NO3)2 solution for 4h and vacuum dried at 50℃ for 16h to obtain photocathode A2, wherein the weight ratio of the substrate, the connecting layer, the aldehyde-based modification layer and the covalent triazine framework metal complex material modification layer is 1:0.015:0.03:0.09.

[0078] Example 3

[0079] 1) Place 40 cm 2 The electrode sheet of the silicon nanowire array was placed in a mixed solution of N-aminoethyl-aminopropyltrimethoxysilane and anhydrous ethanol and refluxed at 75°C for 4 hours to obtain electrode sheet I;

[0080] 2) Electrode I was placed in a mixed solution of bipyridine dicarboxaldehyde and tetrahydrofuran and refluxed at 75°C for 4 h to obtain an aldehyde-modified electrode, wherein the molar volume ratio of bipyridine dicarboxaldehyde and tetrahydrofuran was 1 mmol: 70 mL.

[0081] 3) A mixed solution of 1,4-terephthalamide hydrochloride, strontium carbonate and tetrahydrofuran was added to the above mixed solution of bipyridine dicarboxaldehyde and tetrahydrofuran, refluxed at 110 °C for 8 h, and washed to obtain an electrode sheet modified with a covalent triazine framework material, wherein the molar volume ratio of 1,4-terephthalamide hydrochloride, strontium carbonate and tetrahydrofuran was 1 mmol:7 mmol:70 mL;

[0082] 4) The electrode sheet modified with the above covalent triazine framework material was immersed in 0.4M Ni(NO3)2 solution for 4h and vacuum dried at 70℃ for 8h to obtain photocathode A3, wherein the weight ratio of the substrate, the connecting layer, the aldehyde-based modification layer and the covalent triazine framework metal complex material modification layer is 1:0.025:0.05:0.15.

[0083] Example 4

[0084] 1) Place 40 cm 2 The electrode sheet of the silicon nanowire array was placed in a mixed solution of 3-[2-[2-aminoethylamino]-ethylamino]-propyl-aminotrimethoxysilane and anhydrous ethanol and refluxed at 60°C for 10 h to obtain electrode sheet I.

[0085] 2) Place electrode I in a mixed solution of naphthalene dicarboxaldehyde and dimethyl sulfoxide and reflux at 60°C for 10 h to obtain an aldehyde-modified electrode, wherein the molar volume ratio of naphthalene dicarboxaldehyde and dimethyl sulfoxide is 1 mmol: 40 mL.

[0086] 3) A mixed solution of 1,4-terephthalamide hydrochloride, cesium carbonate and dimethyl sulfoxide was added to the above mixed solution of naphthaldehyde and dimethyl sulfoxide, and refluxed at 80°C for 20 h. After washing, an electrode sheet modified with a covalent triazine framework material was obtained, wherein the molar volume ratio of 1,4-terephthalamide hydrochloride, cesium carbonate and dimethyl sulfoxide was 1 mmol: 2 mmol: 20 mL.

[0087] 4) The electrode sheet modified with the above covalent triazine framework material was immersed in 0.05M Pd(NO3)2 solution for 4h and vacuum dried at 40℃ for 20h to obtain photocathode A4, wherein the weight ratio of the substrate, the connecting layer, the aldehyde-based modification layer and the covalent triazine framework metal complex material modification layer is 1:0.01:0.02:0.06.

[0088] Example 5

[0089] 1) 40 cm 2 The electrode sheet of the silicon nanowire array was placed in a mixed solution of 3-aminopropyltrimethoxysilane and anhydrous ethanol and refluxed at 80°C for 2 hours to obtain electrode sheet I.

[0090] 2) Place electrode sheet I in a mixed solution of biquinoline dicarboxaldehyde and dimethyl sulfoxide, and reflux at 80°C for 2 h to obtain an aldehyde-modified electrode sheet, wherein the molar volume ratio of biquinoline dicarboxaldehyde and dimethyl sulfoxide is 1 mmol: 80 mL.

[0091] 3) A mixed solution of 1,4-terephthalamide hydrochloride, cesium carbonate and dimethyl sulfoxide was added to the above mixed solution of biquinoline dicarboxaldehyde and dimethyl sulfoxide, and refluxed at 120°C for 4 h. After washing, an electrode sheet modified with a covalent triazine framework material was obtained, wherein the molar volume ratio of 1,4-terephthalamide hydrochloride, cesium carbonate and dimethyl sulfoxide was 1 mmol: 8 mmol: 80 mL.

[0092] 4) The electrode sheet modified with the above covalent triazine framework material was immersed in 0.5M HAuCl4 solution for 4h and vacuum dried at 80℃ for 4h to obtain photocathode A5, wherein the weight ratio of the substrate, the connecting layer, the aldehyde-based modification layer and the covalent triazine framework metal complex material modification layer is 1:0.03:0.06:0.18.

[0093] Test case

[0094] The photocathodes prepared in the examples and comparative examples were used to test the preparation of higher alcohol organic compounds.

[0095] Higher alcohol organic compounds are prepared according to the following steps:

[0096] In a 500 mL dual-cell quartz photoelectrolysis cell, photoelectrodes and cathode electrodes were installed in the anode and cathode chambers, respectively, and 180 mL of 0.1 M KHCO3 aqueous solution was added to each chamber. 1 mM organic dye was added to the anode chamber. A silicon solar cell with a voltage of 0.4 V was connected to the electrode. Under illumination, CO2 was introduced into the electrolysis cell to carry out the reaction, and higher carbon alcohol organic compounds were obtained.

[0097] Test Example 1

[0098] Using BiVO4 / Ni as the photoanode and the photocathode prepared in Example 1 as the photocathode, a silicon solar cell provided external power at a voltage of 0.4V. Photoelectrodes and cathode electrodes were installed in the anode and cathode chambers of a 500mL dual-cell quartz photoelectrolysis cell, respectively, and 180mL of 0.1M KHCO3 aqueous solution was added to each chamber. Eosin Y with a concentration of 1mM was added to the anode chamber. After replacing the air in the water with CO2 gas for 30min, the reactor was sealed. The reactor was connected to the silicon solar cell, and CO2 was continuously introduced into the reactor under illumination for 8h of reaction.

[0099] Figure 1 The 1H NMR spectrum of the mixture mainly composed of higher alcohols in Test Example 1 of this invention is obtained from... Figure 1It can be seen that the chemical shift of 0.5-2.5 ppm represents the spectral peaks of hydrogen atoms on the carbon chain.

[0100] Figure 2 The TOF mass spectrum of tridecanol in Test Example 1 of this invention is shown below. Figure 2 As can be seen, the mass number of the main peak, 199.0556, is [MH]. + peak.

[0101] Test conditions: The liquid products obtained in test examples 1-12 were detected and quantified using 1H NMR spectroscopy.

[0102] Specific testing methods. The total amount of higher alcohols was determined using chloroform extraction. The specific testing method is as follows: 1 ¹H NMR analysis was performed using D₂O from 7.0395 mM DMSO as an internal standard, employing a dual-resonance decoupled water peak suppression technique for testing and quantification. The selectivity of tridecanol was calculated based on the integrated peak area of ​​the ¹H NMR spectrum.

[0103] The results are detailed in Table 1.

[0104] Table 1

[0105]

[0106] As shown in Table 1, when the photocathode prepared by this invention is used to prepare higher alcohols, the yield of higher alcohol organic compounds is high and the selectivity of tridecanol is high.

[0107] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A photocathode, characterized in that, The photocathode uses a silicon nanowire array electrode sheet as a substrate. On the surface of the substrate, a connecting layer, an aldehyde-modified layer, and a covalent triazine framework metal complex material modification layer are sequentially coated from the inside to the outside. The weight ratio of the matrix, the connecting layer, the aldehyde-modified layer, and the covalent triazine framework metal complex material modification layer is 1:(0.01-0.03):(0.02-0.06):(0.06-0.18). The compound constituting the connecting layer is a silane coupling agent; The material constituting the covalent triazine framework metal complex material modification layer comprises a covalent triazine framework and a metal complex, wherein the covalent triazine framework is the product of the reaction of an aldehyde organic compound with 1,4-terephthalamide hydrochloride.

2. The photocathode according to claim 1, wherein, The silane coupling agent is selected from at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-aminoethyl-aminopropyltrimethoxysilane, and 3-[2-[2-aminoethylamino]-ethylamino]-propyl-aminotrimethoxysilane.

3. The photocathode according to claim 1, wherein, The compound constituting the aldehyde-modified layer is selected from at least one of 1,4-terephthalaldehyde, biphenyl dicarboxaldehyde, bipyridine dicarboxaldehyde, binaphthalene dicarboxaldehyde, and biquinoline dicarboxaldehyde.

4. The photocathode according to claim 1, wherein, in, The aldehyde organic compound is selected from at least one of 1,4-terephthalaldehyde, biphenyl dicarboxaldehyde, bipyridine dicarboxaldehyde, binaphthalene dicarboxaldehyde, and biquinoline dicarboxaldehyde; the metal complex is selected from at least one of Cu(NO3)2, Co(NO3)2, Ni(NO3)2, Pd(NO3)2, and HAuCl4.

5. A method for preparing a photocathode, characterized in that, The method includes the following steps: 1) The electrode sheet of the silicon nanowire array is placed in a first mixed solution containing silane coupling agent and anhydrous ethanol, and subjected to a first heating and reflux to obtain electrode sheet I; 2) The above electrode sheet I is placed in a second mixed solution containing aldehyde organic matter and the first solvent, and then subjected to a second heating and reflux to obtain an aldehyde-modified electrode sheet; 3) The third mixed solution containing 1,4-terephthalamide hydrochloride, carbonate and the second solvent is mixed with the second mixed solution and subjected to a third heating and reflux and washing to obtain an electrode sheet modified with a covalent triazine framework material; 4) The electrode sheet modified with the above covalent triazine framework material is placed in a metal salt solution and dried to obtain a photocathode.

6. The preparation method according to claim 5, wherein, In step 1), the silane coupling agent is selected from at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-aminoethyl-aminopropyltrimethoxysilane and 3-[2-[2-aminoethylamino]-ethylamino]-propyl-aminotrimethoxysilane.

7. The preparation method according to claim 5, wherein, The conditions for the first heating reflux include: a temperature of 60-80℃ and a time of 2-10h.

8. The preparation method according to claim 5, wherein, In step 2), the aldehyde organic compound is selected from at least one of 1,4-terephthalaldehyde, biphenyl dicarboxaldehyde, bipyridine dicarboxaldehyde, binaphthalene dicarboxaldehyde, and biquinoline dicarboxaldehyde; And / or, the molar volume ratio of the aldehyde organic compound to the first solvent is 1 mmol: (40-80) mL.

9. The preparation method according to claim 5, wherein, The conditions for the second heating and reflux include: a temperature of 60-80℃ and a time of 2-10h.

10. The preparation method according to claim 5, wherein, In step 3), the molar volume ratio of the 1,4-terephthalamide hydrochloride, carbonate, and second solvent is 1 mmol: (2-8) mmol: (20-80) mL.

11. The preparation method according to claim 5, wherein, The carbonate is selected from at least one of cesium carbonate, potassium carbonate, and strontium carbonate.

12. The preparation method according to claim 5, wherein, The conditions for the third heating and reflux include: a temperature of 80-120℃ and a time of 4-20h.

13. The preparation method according to claim 5, wherein, In step 4), the metal salt solution is selected from at least one of aqueous solutions of Cu(NO3)2, Co(NO3)2, Ni(NO3)2, Pd(NO3)2 and HAuCl4; And / or, the concentration of the metal salt solution is 0.05-0.5M.

14. The preparation method according to claim 5, wherein, The drying conditions include a temperature of 60-80℃ and a time of 4-20 hours.

15. The use of a photocathode according to any one of claims 1-4 or a photocathode prepared by any one of claims 5-14 in the preparation of higher alcohol organic compounds.

16. An electrolytic cell, characterized in that, The electrolytic cell comprises a photocathode as described in any one of claims 1-4 or a photocathode prepared by the preparation method described in any one of claims 5-15; the electrolytic cell is used for the preparation of higher alcohol organic compounds.

17. The electrolytic cell according to claim 16, wherein, The electrolytic cell also includes a photoanode, which is selected from any one of BiVO4 / Ni, BiVO4 / Cu, BiVO4 / Al and BiVO4 / Ti.

18. The electrolytic cell according to claim 16, wherein, The electrolytic cell also includes an electrolyte, wherein the electrode solution is an inorganic salt solution selected from aqueous solutions of KHCO3 and / or NaHCO3.

19. The electrolytic cell according to claim 18, wherein, The concentration of the inorganic salt solution is 0.05-0.3 mol / L.

20. A method for preparing a higher carbon alcohol organic compound, characterized in that, The method includes: Under illumination, CO2 is introduced into an electrolytic cell to react and obtain higher carbon alcohol organic compounds; wherein the electrolytic cell is the electrolytic cell described in any one of claims 16-19.

21. The preparation method according to claim 20, wherein, In the reaction, the voltage between the photocathode and photoanode in the electrolytic cell is 0.4-1.8V.

Images