Photocathode, preparation method and application thereof, electrolytic tank and preparation method of high-alcohol organic matter

Abstract

The invention relates to the field of high-alcohol organic matters, and discloses a photocathode and a preparation method and application thereof, an electrolytic tank and a preparation method of a high-alcohol organic matter. The photocathode takes an electrode plate of a silicon nanowire array as a substrate; a connecting layer, an aldehyde group modification layer and a covalent triazine framework metal complex material modification layer are sequentially coated from inside to outside; wherein the weight ratio of the matrix to the connecting layer to the aldehyde group modification layer to the 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 the invention has the capability of adsorbing carbon dioxide, and the selectivity of high-carbon-alcohol organic matters and the reduction capability of carbon dioxide are improved; according to the preparation method, operation conditions and technological processes are simplified, and industrial production is facilitated; the photocathode provided by the invention is used for preparing high-alcohol organic matters, and has excellent carbon dioxide adsorption performance, high selectivity and high product quantity.

Description

Technical Field

[0001] The invention relates to the field of high-carbon alcohol organic matter, and in particular to a photocathode and a preparation method and application thereof, an electrolytic cell and a preparation method of high-carbon alcohol organic matter. Background Art

[0002] With the rapid development of industrialization and modernization, the emission of carbon dioxide (CO2) has increased year by year. As the main component of greenhouse gases, CO2 has caused global warming and frequent extreme weather, which has seriously affected people's lives. As a widely distributed, abundant, environmentally friendly, green and sustainable energy source, solar energy has been valued by countries around the world. Using solar energy as a driving force to convert CO2 and water into organic matter is a green chemical technology that people have long dreamed of. It is an essential technology to achieve the grand goal of carbon neutrality. At present, the research on the catalytic reduction of carbon dioxide in water is mainly electrocatalytic, photocatalytic and photoelectric combined catalytic methods. The reduction products are mainly formic acid, carbon monoxide, methane, and other small molecular organic substances. Most of the products reported so far have poor selectivity and low yield, and there are still certain difficulties in their application in actual industrial production.

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

[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, it is limited by the poor conductivity, fragility, heavy weight and high price of FTO glass electrodes, and its application prospects are limited.

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

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

[0007] The purpose of the present invention is to overcome the problems of poor carbon dioxide adsorption performance, poor organic selectivity and low product yield in the prior art when preparing high-carbon alcohols by photoelectric combined catalysis, and to provide a photocathode and its preparation method and application, an electrolytic cell and a method for preparing high-carbon alcohol organic matter.

[0008] In order to achieve the above-mentioned object, the first aspect of the present invention provides a photocathode, wherein the photocathode uses an electrode sheet of a silicon nanowire array as a substrate, and on the surface of the substrate, a connecting layer, an aldehyde 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 substrate, the connecting layer, the aldehyde modified layer and the covalent triazine framework metal complex modified 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 comprises the following steps:

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

[0012] 2) placing the electrode sheet I in a second mixed solution containing an aldehyde organic compound and a first solvent, and heating and refluxing for a second time to obtain an aldehyde-modified electrode sheet;

[0013] 3) mixing a third mixed solution containing 1,4-terephthalamidine hydrochloride, carbonate and a second solvent with the second mixed solution and performing heating reflux and washing for a third time to obtain an electrode sheet modified with a covalent triazine framework material;

[0014] 4) placing the electrode sheet modified with the covalent triazine framework material in a metal salt solution and drying the solution to obtain a photocathode.

[0015] The third aspect of the present invention provides the use of the above-mentioned photocathode in the preparation of high-carbon alcohol organic matter.

[0016] A fourth aspect of the present invention provides an electrolytic cell, wherein the electrolytic cell comprises the photocathode of the present invention or the photocathode prepared by the preparation method of the present invention; the electrolytic cell is used for preparing high-carbon alcohol organic matter;

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

[0018] Preferably, the electrolytic cell further comprises an electrolyte, the electrolyte is an inorganic salt solution, and the inorganic salt solution is selected from an aqueous solution 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 a higher alcohol organic compound, wherein the method comprises:

[0021] Under light conditions, CO2 is introduced into an electrolytic cell for reaction to obtain a high-carbon alcohol organic matter; wherein the electrolytic cell is the electrolytic cell according to claim 9;

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

[0023] Through the above technical scheme, the photocathode and its preparation method and application, electrolytic cell and preparation method of high-carbon alcohol organic matter 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 a substrate, and the surface of the substrate is sequentially 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, improves the selectivity of high-carbon alcohol organic matter and the ability to reduce carbon dioxide;

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

[0026] (3) The photocathode provided by the present invention is used to prepare high-carbon alcohol organic matter, which has excellent carbon dioxide adsorption performance, high selectivity and product amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the nuclear magnetic resonance hydrogen spectrum of the mixture mainly composed of higher carbon alcohols in Test Example 1 of the present invention;

[0028] Figure 2 This is the TOF mass spectrum of tridecanol in Test Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0030] The first aspect of the present invention provides a photocathode, wherein the photocathode uses an electrode sheet of a silicon nanowire array as a substrate, and on the surface of the substrate, a connecting layer, an aldehyde 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 substrate, the connecting layer, the aldehyde modified layer and the covalent triazine framework metal complex modified layer is 1:(0.01-0.03):(0.02-0.06):(0.06-0.18).

[0032] In the present invention, the photocathode has the advantages of being able to adsorb carbon dioxide, improving the selectivity of high-carbon alcohol organic matter, and improving the ability to reduce carbon dioxide.

[0033] In the present invention, when the weight ratio of the substrate, the connecting layer, the aldehyde modified layer and the covalent triazine framework metal complex modified 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 at least one selected from 1,4-terephthalaldehyde, biphenyldicarboxaldehyde, bipyridinedicarboxaldehyde, binaphthyldicarboxaldehyde and biquinolinedicarboxaldehyde.

[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 the product of the reaction of an aldehyde-based organic matter with 1,4-terephthalamidine hydrochloride; wherein the aldehyde-based organic matter is selected from at least one of 1,4-terephthalaldehyde, biphenyl dicarboxaldehyde, bipyridine dicarboxaldehyde, dinaphthaldehyde 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 comprises the following steps:

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

[0039] 2) placing the electrode sheet I in a second mixed solution containing an aldehyde organic compound and a first solvent, and heating and refluxing for a second time to obtain an aldehyde-modified electrode sheet;

[0040] 3) mixing a third mixed solution containing 1,4-terephthalamidine hydrochloride, carbonate and a second solvent with the second mixed solution and performing heating reflux and washing for a third time to obtain an electrode sheet modified with a covalent triazine framework material;

[0041] 4) placing the electrode sheet modified with the covalent triazine framework material in a metal salt solution and drying the solution to obtain a photocathode.

[0042] In the present invention, the covalent triazine framework material is a type of crystalline porous solid organic material, which has the characteristics of high specific surface area, tailorability, functionalization, multiple active sites, etc. The use of this material in the photocathode can reduce the reflection of light and improve the absorption capacity of carbon dioxide, thereby improving the photocathode's reduction efficiency of carbon dioxide and selectivity for high-carbon alcohol organic matter.

[0043] According to the present invention, in step 1), the mass volume ratio of the electrode sheet of the silicon nanowire array, the silane coupling agent and anhydrous ethanol is 1 g: (0.002-0.008) g: (5-10) mL.

[0044] According to the present invention, in step 1), the conditions of the first heating reflux include: temperature of 60-80° C. and time of 2-10 h.

[0045] 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.

[0046] 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.

[0047] According to the present invention, in step 2), the conditions for the second heating reflux include: temperature of 60-80° C. and time of 2-10 h.

[0048] According to the present invention, in step 3), the molar volume ratio of the 1,4-terephthalamidine hydrochloride, the carbonate and the second solvent is 1 mmol:(2-8) mmol:(20-80) mL.

[0049] According to the present invention, in step 3), the carbonate is selected from at least one of cesium carbonate, potassium carbonate and strontium carbonate.

[0050] According to the present invention, in step 3), the conditions for the third heating reflux include: temperature of 80-120° C. and time of 4-20 h.

[0051] According to the present invention, 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.

[0052] According to the present invention, in step 4), the concentration of the metal salt solution is 0.05-0.5M.

[0053] According to the present invention, in step 4), the drying conditions include: temperature of 60-80° C. and time of 4-20 h.

[0054] The third aspect of the present invention provides the use of the above-mentioned photocathode in the preparation of high-carbon alcohol organic matter.

[0055] A fourth aspect of the present invention provides an electrolytic cell, wherein the electrolytic cell comprises the photocathode of the present invention or the photocathode prepared by the preparation method of the present invention; the electrolytic cell is used for preparing high-carbon alcohol organic matter;

[0056] Preferably, the electrolytic cell further comprises a photoanode, and the photoanode is selected from any one of BiVO4 / Ni, BiVO4 / Cu, BiVO4 / Al and BiVO4 / Ti;

[0057] Preferably, the electrolytic cell further comprises an electrolyte, the electrolyte is an inorganic salt solution, and the inorganic salt solution is selected from an aqueous solution of KHCO3 and / or NaHCO3;

[0058] Preferably, the concentration of the inorganic salt solution is 0.05-0.3 mol / L.

[0059] In the present invention, the preparation method of the photoanode is to use a three-electrode system, a reference electrode: Ag / AgCl; a counter electrode: Pt wire; a working electrode: foamed nickel or copper or aluminum or titanium; electrolysis is performed at a bias voltage of 0.1V for 100-300s, and then washed with deionized water and dried to obtain an orange-red BiOI / Ni or BiOI / Cu or BiOI / Al or BiOI / Ti electrode. 850mg of NH4VO3 is dissolved in 250mL of deionized water and transferred to a hydrothermal reactor, and the synthesized BiOI / Ni or BiOI / Cu or BiOI / Al or BiOI / Ti electrode is placed in the reactor, hydrothermally heated at 120°C, reacted for 12h, cooled to room temperature, and soaked in 1M NaOH for 10min to obtain a suitable BiVO4 / Ni or BiVO4 / Cu or BiVO4 / Al or BiVO4 / Ti photoanode.

[0060] According to the present invention, the electrolytic cell is separated into an anode chamber and a cathode chamber by a proton membrane.

[0061] According to the present invention, the electrolyte in the anode chamber further comprises an organic dye.

[0062] Furthermore, the organic dye is selected from at least one of eosin Y, methylene blue, Nile red and methyl violet.

[0063] In the present invention, the concentration of the organic dye is 1-3 mM.

[0064] A fifth aspect of the present invention provides a method for preparing a higher alcohol organic compound, wherein the method comprises:

[0065] Under light conditions, CO2 is introduced into an electrolytic cell for reaction to obtain a high-carbon alcohol organic matter; wherein the electrolytic cell is the electrolytic cell of the present invention;

[0066] Preferably, in the reaction, the voltage between the photocathode and the photoanode in the electrolytic cell is 0.4-1.8V.

[0067] The present invention will be described in detail below by way of examples. In the following examples,

[0068] The raw materials used in the examples and comparative examples are all commercially available.

[0069] Example 1

[0070] 1) 40cm 2 The electrode sheet of the silicon nanowire array is placed in a mixed solution of 3-aminopropyltriethoxysilane and anhydrous ethanol, and refluxed at 70°C for 6 hours to obtain electrode sheet I, wherein the mass volume ratio of the electrode sheet of the silicon nanowire array, 3-aminopropyltriethoxysilane and anhydrous ethanol is 1g:0.005g:7.5mL;

[0071] 2) placing the electrode sheet I in a mixed solution of 1,4-terephthalaldehyde and dimethyl sulfoxide, and refluxing at 70° C. for 6 h to obtain an aldehyde-modified electrode sheet, wherein the molar volume ratio of 1,4-terephthalaldehyde to the first solvent is 1 mmol:60 mL;

[0072] 3) adding a mixed solution of 1,4-terephthalamidine hydrochloride, cesium carbonate and dimethyl sulfoxide to the mixed solution of 1,4-terephthalaldehyde and dimethyl sulfoxide, refluxing at 100° C. for 12 h, washing, and obtaining an electrode sheet modified with a covalent triazine framework material, wherein the molar volume ratio of 1,4-terephthalamidine hydrochloride, cesium carbonate and dimethyl sulfoxide is 1 mmol:5 mmol:50 mL;

[0073] 4) The electrode sheet modified with the above covalent triazine framework material was immersed in a 0.3M Cu(NO3)2 solution for 4 hours, and vacuum dried at 60°C for 12 hours to obtain a photocathode A1, wherein the weight ratio of the substrate, the connecting layer, the aldehyde modified layer and the covalent triazine framework metal complex material modified layer was 1:0.02:0.04:0.12.

[0074] Example 2

[0075] 1) 40cm 2 The electrode sheet of the silicon nanowire array is placed in a mixed solution of 3-aminopropyltrimethoxysilane and anhydrous ethanol, and refluxed at 65° C. for 8 h to obtain electrode sheet I, wherein the mass volume ratio of the electrode sheet of the silicon nanowire array, 3-aminopropyltrimethoxysilane and anhydrous ethanol is 1 g:0.003 g:6.5 mL;

[0076] 2) placing the electrode sheet I in a mixed solution of biphenyl dicarboxaldehyde and N,N-dimethylformamide, and reflux at 65°C for 8 hours to obtain an aldehyde-modified electrode sheet, wherein the molar volume ratio of biphenyl dicarboxaldehyde to N,N-dimethylformamide is 1 mmol:50 mL;

[0077] 3) adding a mixed solution of 1,4-terephthalamidine hydrochloride, potassium carbonate and N,N-dimethylformamide to the mixed solution of biphenyl dicarboxaldehyde and N,N-dimethylformamide, reflux at 90° C. for 16 h, and wash to obtain an electrode sheet modified with a covalent triazine framework material, wherein the molar volume ratio of 1,4-terephthalamidine hydrochloride, potassium carbonate and N,N-dimethylformamide is 1 mmol:3 mmol:30 mL;

[0078] 4) The electrode sheet modified with the above covalent triazine framework material was immersed in a 0.15M Co(NO3)2 solution for 4 hours, and vacuum dried at 50°C for 16 hours to obtain a photocathode A2, wherein the weight ratio of the substrate, the connecting layer, the aldehyde modified layer and the covalent triazine framework metal complex modified layer was 1:0.015:0.03:0.09.

[0079] Example 3

[0080] 1) 40cm 2 The electrode sheet of the silicon nanowire array is 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, wherein the mass volume ratio of the electrode sheet of the silicon nanowire array, N-aminoethyl-aminopropyltrimethoxysilane and anhydrous ethanol is 1g:0.007g:8.5mL;

[0081] 2) placing the electrode sheet I in a mixed solution of bipyridine dicarboxaldehyde and tetrahydrofuran, and reflux at 75° C. for 4 h to obtain an aldehyde-modified electrode sheet, wherein the molar volume ratio of bipyridine dicarboxaldehyde to tetrahydrofuran is 1 mmol:70 mL;

[0082] 3) adding a mixed solution of 1,4-terephthalamidine hydrochloride, strontium carbonate and tetrahydrofuran to the mixed solution of bipyridine dicarboxaldehyde and tetrahydrofuran, reflux at 110° C. for 8 h, and wash to obtain an electrode sheet modified with a covalent triazine framework material, wherein the molar volume ratio of 1,4-terephthalamidine hydrochloride, strontium carbonate and tetrahydrofuran is 1 mmol:7 mmol:70 mL;

[0083] 4) The electrode sheet modified with the above covalent triazine framework material was immersed in a 0.4M Ni(NO3)2 solution for 4 hours, and vacuum dried at 70°C for 8 hours to obtain a photocathode A3, wherein the weight ratio of the substrate, the connecting layer, the aldehyde modified layer and the covalent triazine framework metal complex modified layer was 1:0.025:0.05:0.15.

[0084] Example 4

[0085] 1) 40cm 2 The electrode sheet of the silicon nanowire array is 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, wherein the mass volume ratio of the electrode sheet of the silicon nanowire array, 3-[2-[2-aminoethylamino]-ethylamino]-propyl-aminotrimethoxysilane and anhydrous ethanol is 1 g:0.002 g:5 mL;

[0086] 2) placing the electrode sheet I in a mixed solution of binaphthaldehyde and dimethyl sulfoxide, and refluxing at 60° C. for 10 h to obtain an aldehyde-modified electrode sheet, wherein the molar volume ratio of binaphthaldehyde to dimethyl sulfoxide is 1 mmol:40 mL;

[0087] 3) adding a mixed solution of 1,4-terephthalamidine hydrochloride, cesium carbonate and dimethyl sulfoxide to the mixed solution of binaphthaldehyde and dimethyl sulfoxide, reflux at 80° C. for 20 h, and wash to obtain an electrode sheet modified with a covalent triazine framework material, wherein the molar volume ratio of 1,4-terephthalamidine hydrochloride, cesium carbonate and dimethyl sulfoxide is 1 mmol:2 mmol:20 mL;

[0088] 4) The electrode sheet modified with the above covalent triazine framework material was immersed in a 0.05M Pd(NO3)2 solution for 4 hours, and vacuum dried at 40°C for 20 hours to obtain a photocathode A4, wherein the weight ratio of the substrate, the connecting layer, the aldehyde modified layer and the covalent triazine framework metal complex modified layer was 1:0.01:0.02:0.06.

[0089] Example 5

[0090] 1) 40cm 2 The electrode sheet of the silicon nanowire array is placed in a mixed solution of 3-aminopropyltrimethoxysilane and anhydrous ethanol, and refluxed at 80° C. for 2 h to obtain electrode sheet I, wherein the mass volume ratio of the electrode sheet of the silicon nanowire array, 3-aminopropyltrimethoxysilane and anhydrous ethanol is 1 g:0.008 g:10 mL;

[0091] 2) placing the electrode sheet I in a mixed solution of biquinoline dicarboxaldehyde and dimethyl sulfoxide, and refluxing at 80° C. for 2 h to obtain an aldehyde-modified electrode sheet, wherein the molar volume ratio of biquinoline dicarboxaldehyde to dimethyl sulfoxide is 1 mmol:80 mL;

[0092] 3) adding a mixed solution of 1,4-terephthalamidine hydrochloride, cesium carbonate and dimethyl sulfoxide to the mixed solution of the above-mentioned biquinoline dicarboxaldehyde and dimethyl sulfoxide, reflux at 120° C. for 4 hours, and wash to obtain an electrode sheet modified with a covalent triazine framework material, wherein the molar volume ratio of 1,4-terephthalamidine hydrochloride, cesium carbonate and dimethyl sulfoxide is 1 mmol:8 mmol:80 mL;

[0093] 4) The electrode sheet modified with the above covalent triazine framework material was immersed in a 0.5M HAuCl4 solution for 4 hours, and vacuum dried at 80°C for 4 hours to obtain a photocathode A5, wherein the weight ratio of the substrate, the connecting layer, the aldehyde modified layer and the covalent triazine framework metal complex modified layer was 1:0.03:0.06:0.18.

[0094] Test Case

[0095] The photocathodes prepared in the examples and comparative examples were tested for preparing high-carbon alcohol organic substances.

[0096] The high carbon alcohol organic matter is prepared according to the following steps:

[0097] A photoelectrode and a cathode electrode were installed in the anode chamber and cathode chamber of a 500mL double-cell quartz photoelectrolytic cell, respectively, and 180mL of a 0.1M KHCO3 aqueous solution was added to each chamber. 1mM of an organic dye was added to the anode chamber. A silicon solar cell with a voltage of 0.4V was connected to the electrodes. Under light conditions, CO2 was passed into the electrolytic cell for reaction to obtain high-carbon alcohol organic matter.

[0098] Test Example 1

[0099] BiVO4 / Ni was used as the photoanode, the photocathode prepared in Example 1 was used as the photocathode, and the silicon solar cell provided external power with a voltage of 0.4V. The photoelectrode and the cathode were installed in the anode chamber and cathode chamber of a 500mL double-cell quartz photoelectrolyzer, and 180mL of 0.1M KHCO3 aqueous solution were added respectively. Eosin Y was added to the anode chamber at a concentration of 1mM. The air in the water was replaced with CO2 gas for 30min and the reactor was sealed. The reactor was connected to the silicon solar cell, and CO2 was continuously introduced into the reactor for reaction for 8h under light conditions.

[0100] Figure 1 is the nuclear magnetic resonance hydrogen spectrum of the mixture mainly composed of high carbon alcohols in Test Example 1 of the present invention, Figure 1 It can be seen that the chemical shift of 0.5-2.5 ppm is the spectral peak of hydrogen atoms on the carbon chain.

[0101] Figure 2 is the TOF mass spectrum of tridecanol in Test Example 1 of the present invention, Figure 2 It can be seen that the main peak mass number 199.0556 is [MH] + peak.

[0102] Test conditions: The liquid products obtained in Test Examples 1-12 were detected and quantified using hydrogen nuclear magnetic resonance spectroscopy.

[0103] Specific test method. The total amount of high carbon alcohol is extracted by chloroform. The specific test method is: 1 HNMR analysis was performed using 7.0395 mM DMSO D2O as the internal standard and double resonance decoupling water peak suppression technology for testing and quantitative analysis. The selectivity of tridecanol was calculated based on the peak integral area of ​​the H NMR spectrum.

[0104] The results are shown in Table 1.

[0105] Table 1

[0106] Total amount of higher alcohol organic matter (mg) Tridecanol selectivity (%) Test Example 1 104 51

[0107] It can be seen from Table 1 that when the photocathode prepared by the present invention is used to prepare higher carbon alcohols, the yield of higher carbon alcohol organic matter is high and the selectivity of tridecanol is high.

[0108] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A photocathode, characterized in that: The photocathode uses an electrode sheet of a silicon nanowire array as a substrate, and on the surface of the substrate, a connection layer, an aldehyde modification 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 substrate, the connecting layer, the aldehyde modified layer and the covalent triazine framework metal complex modified layer is 1:(0.01-0.03):(0.02-0.06):(0.06-0.18).

2. The photocathode according to claim 1, wherein 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; Preferably, the compound constituting the aldehyde-modified layer is selected from at least one of 1,4-terephthalaldehyde, biphenyldicarboxaldehyde, bipyridinedicarboxaldehyde, binaphthyldicarboxaldehyde and biquinolinedicarboxaldehyde; Preferably, 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-based organic matter with 1,4-terephthalamidine hydrochloride; wherein the aldehyde-based organic matter is selected from at least one of 1,4-terephthalaldehyde, biphenyl dicarboxaldehyde, bipyridine dicarboxaldehyde, dinaphthaldehyde 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.

3. A method for preparing a photocathode, characterized in that: The method comprises the following steps: 1) placing the electrode sheet of the silicon nanowire array in a first mixed solution containing a silane coupling agent and anhydrous ethanol, and performing a first heating reflux to obtain an electrode sheet I; 2) placing the electrode sheet I in a second mixed solution containing an aldehyde organic compound and a first solvent, and heating and refluxing for a second time to obtain an aldehyde-modified electrode sheet; 3) mixing a third mixed solution containing 1,4-terephthalamidine hydrochloride, carbonate and a second solvent with the second mixed solution and performing heating reflux and washing for a third time to obtain an electrode sheet modified with a covalent triazine framework material; 4) placing the electrode sheet modified with the covalent triazine framework material in a metal salt solution and drying the solution to obtain a photocathode.

4. The preparation method according to claim 3, 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; Preferably, the mass volume ratio of the electrode sheet of the silicon nanowire array, the silane coupling agent and anhydrous ethanol is 1 g: (0.002-0.008) g: (5-10) mL; Preferably, the conditions of the first heating reflux include: temperature of 60-80° C. and time of 2-10 h.

5. The preparation method according to claim 3 or 4, wherein In step 2), the aldehyde organic compound is selected from at least one of 1,4-terephthalaldehyde, biphenyldicarboxaldehyde, bipyridinedicarboxaldehyde, binaphthyldicarboxaldehyde and biquinolinedicarboxaldehyde; Preferably, the molar volume ratio of the aldehyde organic compound to the first solvent is 1 mmol: (40-80) mL; Preferably, the conditions for the second heating reflux include: temperature of 60-80° C. and time of 2-10 h.

6. The preparation method according to any one of claims 3 to 5, characterized in that: In step 3), the molar volume ratio of the 1,4-terephthalamidine hydrochloride, the carbonate and the second solvent is 1 mmol:(2-8) mmol:(20-80) mL; Preferably, the carbonate is selected from at least one of cesium carbonate, potassium carbonate and strontium carbonate; Preferably, the conditions for the third heating reflux include: temperature of 80-120° C. and time of 4-20 h.

7. The preparation method according to any one of claims 3 to 6, 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; Preferably, the concentration of the metal salt solution is 0.05-0.5M; Preferably, the drying conditions include: temperature of 60-80° C. and time of 4-20 h.

8. Use of the photocathode according to claim 1 or 2 or the photocathode prepared by the preparation method according to any one of claims 3 to 7 in the preparation of higher alcohol organic matter.

9. An electrolytic cell, characterized in that The electrolytic cell comprises the photocathode according to claim 1 or 2 or the photocathode prepared by the preparation method according to any one of claims 3 to 7; the electrolytic cell is used for the preparation of high-carbon alcohol organic matter; Preferably, the electrolytic cell further comprises a photoanode, and the photoanode is selected from any one of BiVO4 / Ni, BiVO4 / Cu, BiVO4 / Al and BiVO4 / Ti; Preferably, the electrolytic cell further comprises an electrolyte, the electrolyte is an inorganic salt solution, and the inorganic salt solution is selected from an aqueous solution of KHCO3 and / or NaHCO3; Preferably, the concentration of the inorganic salt solution is 0.05-0.3 mol / L.

10. A method for preparing a high carbon alcohol organic compound, characterized in that: The method comprises: Under light conditions, CO2 is introduced into an electrolytic cell for reaction to obtain a high-carbon alcohol organic matter; wherein the electrolytic cell is the electrolytic cell according to claim 9; Preferably, in the reaction, the voltage between the photocathode and the photoanode in the electrolytic cell is 0.4-1.8V.

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