CN115815611A - Super-hydrophobic nano porous silver-based material and preparation method and application thereof - Google Patents
Super-hydrophobic nano porous silver-based material and preparation method and application thereof Download PDFInfo
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- 229910052709 silver Inorganic materials 0.000 title claims abstract description 120
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 title claims abstract description 117
- 239000004332 silver Substances 0.000 title claims abstract description 117
- 239000000463 material Substances 0.000 title claims abstract description 113
- 230000003075 superhydrophobic effect Effects 0.000 title claims abstract description 66
- 238000002360 preparation method Methods 0.000 title claims abstract description 23
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 116
- 239000007864 aqueous solution Substances 0.000 claims abstract description 85
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 claims abstract description 84
- 239000000243 solution Substances 0.000 claims abstract description 70
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 52
- 229910021607 Silver chloride Inorganic materials 0.000 claims abstract description 47
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 claims abstract description 47
- 239000002245 particle Substances 0.000 claims abstract description 43
- 229910000033 sodium borohydride Inorganic materials 0.000 claims abstract description 43
- 239000012279 sodium borohydride Substances 0.000 claims abstract description 43
- 238000003756 stirring Methods 0.000 claims abstract description 43
- 229910001961 silver nitrate Inorganic materials 0.000 claims abstract description 42
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims abstract description 34
- 239000002244 precipitate Substances 0.000 claims abstract description 34
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 32
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 29
- 238000002156 mixing Methods 0.000 claims abstract description 29
- 238000001035 drying Methods 0.000 claims abstract description 25
- 239000002904 solvent Substances 0.000 claims abstract description 23
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 14
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims abstract description 13
- 235000011114 ammonium hydroxide Nutrition 0.000 claims abstract description 13
- 230000009467 reduction Effects 0.000 claims abstract description 9
- 238000004140 cleaning Methods 0.000 claims abstract description 7
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 63
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 41
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 41
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 40
- 239000000203 mixture Substances 0.000 claims description 34
- 229910021529 ammonia Inorganic materials 0.000 claims description 29
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 26
- 239000007787 solid Substances 0.000 claims description 23
- 238000000034 method Methods 0.000 claims description 15
- 238000005406 washing Methods 0.000 claims description 15
- 238000005119 centrifugation Methods 0.000 claims description 8
- 239000010411 electrocatalyst Substances 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 6
- 238000006243 chemical reaction Methods 0.000 abstract description 28
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 abstract description 2
- 229920000523 polyvinylpolypyrrolidone Polymers 0.000 abstract 1
- 239000001253 polyvinylpolypyrrolidone Substances 0.000 abstract 1
- 235000013809 polyvinylpolypyrrolidone Nutrition 0.000 abstract 1
- LSDPWZHWYPCBBB-UHFFFAOYSA-N Methanethiol Chemical compound SC LSDPWZHWYPCBBB-UHFFFAOYSA-N 0.000 description 25
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 12
- 238000012512 characterization method Methods 0.000 description 12
- 238000012360 testing method Methods 0.000 description 11
- 239000000126 substance Substances 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 8
- 238000006722 reduction reaction Methods 0.000 description 8
- 239000003792 electrolyte Substances 0.000 description 7
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 238000000862 absorption spectrum Methods 0.000 description 6
- 235000019270 ammonium chloride Nutrition 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 6
- 229910052739 hydrogen Inorganic materials 0.000 description 6
- 238000000634 powder X-ray diffraction Methods 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 238000002835 absorbance Methods 0.000 description 4
- 239000002131 composite material Substances 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
- 239000012467 final product Substances 0.000 description 4
- 230000002209 hydrophobic effect Effects 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- YGSDEFSMJLZEOE-UHFFFAOYSA-N salicylic acid Chemical compound OC(=O)C1=CC=CC=C1O YGSDEFSMJLZEOE-UHFFFAOYSA-N 0.000 description 4
- 239000012488 sample solution Substances 0.000 description 4
- 239000011734 sodium Substances 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 238000006555 catalytic reaction Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
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- 230000002441 reversible effect Effects 0.000 description 3
- VRZJGENLTNRAIG-UHFFFAOYSA-N 4-[4-(dimethylamino)phenyl]iminonaphthalen-1-one Chemical compound C1=CC(N(C)C)=CC=C1N=C1C2=CC=CC=C2C(=O)C=C1 VRZJGENLTNRAIG-UHFFFAOYSA-N 0.000 description 2
- 238000009620 Haber process Methods 0.000 description 2
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- 229910000069 nitrogen hydride Inorganic materials 0.000 description 2
- FJKROLUGYXJWQN-UHFFFAOYSA-N papa-hydroxy-benzoic acid Natural products OC(=O)C1=CC=C(O)C=C1 FJKROLUGYXJWQN-UHFFFAOYSA-N 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 229960004889 salicylic acid Drugs 0.000 description 2
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical group [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 2
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 1
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- 229910017604 nitric acid Inorganic materials 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
- Y02P20/133—Renewable energy sources, e.g. sunlight
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Abstract
The invention discloses a super-hydrophobic nano porous silver material and a preparation method and application thereof, wherein the preparation method comprises the following steps: uniformly mixing a polyvinyl polypyrrolidone aqueous solution and a silver nitrate aqueous solution, dripping hydrochloric acid, stirring, centrifuging, cleaning to obtain AgCl cubic particles, uniformly mixing AgCl cubic particles, water and glycol to obtain an AgCl cubic particle solution, dripping a sodium borohydride aqueous solution into the AgCl cubic particle solution, adding ammonia water, stirring, adding acetone, centrifuging, cleaning, drying to obtain a nano porous silver material, uniformly mixing the nano porous silver material and a solvent to obtain a reaction solution, dripping a PFDT ethanol solution into the reaction solution, stirring, centrifuging to obtain a first precipitate, mixing the first precipitate with the solvent, dripping the PFDT ethanol solution again, stirring for reaction, and centrifuging to obtain a second precipitate to obtain the superhydrophobic nano porous silver-based material with good electrochemical stability, wherein the superhydrophobic nano porous silver-based material has the advantages of nitrogen reduction electrocatalytic performance and the like.
Description
Technical Field
The invention belongs to the technical field of electrocatalytic nitrogen fixation materials, and particularly relates to a super-hydrophobic nano porous silver-based material, and a preparation method and application thereof.
Background
With the increasing global population, the depletion of fossil fuels and the pressing global environmental issues, there is an urgent need to find sustainable, renewable and eco-friendly energy sources to ensure the continuous supply of energy in the future. As is well known, N 2 Is the most abundant molecule in the atmosphere. Due to the high N ≡ N bond energy, no dipole moment, and low polarizability, it is one of the most inert chemical species. And NH 3 Is an important chemical raw material, about 80 percent of ammonia gas in industrial production is converted into chemical fertilizer, and contributes to the population growth on the earth. In addition to agriculture, NH 3 Is mainly used in the plastics and textile industries and as a stable hydrogen carrier. Currently, there are three typical nitrogen fixation pathways, natural biological nitrogen fixation, the Haber-Bosch process, and electrocatalysis. The green biological nitrogen fixation hardly meets the huge demand of the current fertilizer industry; achieving mainly N on an industrial scale by means of the Haber-Bosch process 2 Reduction to NH 3 The process was developed by Fritz Haber and Carl Bosch over one more century ago using a heterogeneous iron-based catalyst at high temperature (350-550 deg.C) and high pressure (150-300 atm) through high purity N 2 And H 2 Gas is produced. However, H used in the reaction 2 Molecules are mainly other fossil fuels obtained from natural gas or dissociation of natural gas, which results in consumption of large amounts of energy and emission of large amounts of greenhouse gases.
Concerns over climate change caused by human activity are driving the international scientific community to explore new ways to produce ammonia and reduce its carbon footprint. Electrocatalytic N 2 Reducing ammonia is an attractive alternative to the use of renewable electricity generated from solar or wind power to synthesize ammonia in small-scale, distributed and on-site electrolytic cells at ambient temperature and pressure. The noble metal nano material catalyst is widely applied to electrocatalytic reaction including ammonia production by nitrogen reduction due to high active sites and good conductivity, but the traditional solid nano particles have poor stability, so the active sites are reduced and are not usedCan inhibit the strong hydrogen evolution reaction in water, so that the ammonia production effect is greatly influenced, and the industrial application of ammonia production is seriously limited.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a preparation method based on a super-hydrophobic nano-porous silver material.
The invention also aims to provide the superhydrophobic nanoporous silver-based material obtained by the preparation method, and the superhydrophobic nanoporous silver-based material has a porous hollow structure and a spheroid-like nanoparticle morphology.
The invention also aims to provide application of the super-hydrophobic nano-porous silver-based material as an electrocatalyst in preparation of ammonia by nitrogen reduction.
The purpose of the invention is realized by the following technical scheme.
A preparation method based on a super-hydrophobic nano-porous silver material comprises the following steps:
1) Uniformly mixing a polyvinyl pyrrolidone aqueous solution and a silver nitrate aqueous solution, dripping hydrochloric acid, stirring until the color of the liquid is changed from colorless and transparent to white, centrifuging to obtain a solid, sequentially washing the solid with water and ethanol, and drying to obtain a white solid which is AgCl cubic particles, wherein the ratio of the polyvinyl pyrrolidone in the polyvinyl pyrrolidone aqueous solution to the silver nitrate in the silver nitrate aqueous solution to the HCl in the hydrochloric acid is (3 multiplied by 10) according to the parts by weight of the substances -4 ～4×10 -4 ):2.35:(4×10 -4 ～5×10 -4 )。
In the step 1), the aqueous solution of the polyvinylpyrrolidone and the aqueous solution of the silver nitrate are mixed, and stirred at the room temperature of 20-25 ℃ for 10-15 minutes at the speed of 400-500 rpm, so that the aqueous solution of the polyvinylpyrrolidone and the aqueous solution of the silver nitrate are uniformly mixed.
In the step 1), the concentration of the polyvinylpyrrolidone in the polyvinylpyrrolidone aqueous solution is 0.1-0.3 mg/mL, the concentration of the silver nitrate in the silver nitrate aqueous solution is 0.15-0.25 mg/mL, and the concentration of HCl in the hydrochloric acid is 5.5-6.5 mol/L.
2) Uniformly mixing 40-60 parts by mass of AgCl cubic particles, 4.5-5.5 parts by volume of water and 40-50 parts by volume of ethylene glycol to obtain an AgCl cubic particle solution, dropwise adding 1-2 parts by volume of sodium borohydride aqueous solution into the AgCl cubic particle solution, stirring until the solution gradually turns from white to grey black, adding 4-5 parts by volume of ammonia water, stirring for 1-2 min, adding 4-5 parts by volume of acetone, centrifuging to obtain a precipitate, cleaning the precipitate, and drying to obtain the nano porous silver material, wherein the unit of the mass parts is mg, the unit of the volume parts is mL, and the ratio of the AgCl cubic particles to the sodium borohydride aqueous solution is (4-6): 2;
in the step 2), the concentration of sodium borohydride in the sodium borohydride aqueous solution is 10-20 mg/mL, and the method for preparing the sodium borohydride aqueous solution comprises the following steps: mixing sodium borohydride with water under ice bath conditions (0-1 ℃) to obtain the sodium borohydride aqueous solution.
In the step 2), the method for uniformly mixing the AgCl cubic particles, water and glycol comprises the following steps: the AgCl cubic particles and water are mixed uniformly, then the ethylene glycol is added, and the mixture is stirred for 20 to 30 seconds.
In the step 2), the stirring time for gradually changing the solution from white to grey-black is 20 to 30 minutes.
In the step 2), the precipitate is washed with ethanol.
In the step 2), the stirring speed is 500 to 600rpm.
In the technical scheme, the drying is carried out in a vacuum environment, the drying temperature is 30-40 ℃, and the drying time is 1-3 hours.
In the step 2), the concentration of the ammonia water is 25-28 wt%;
3) <xnotran> 4 ～ 5 1 ～ 2 , , 1 ～ 2 1H,1H,2H,2H- , 3 ～ 4 , , 1 ～ 2 , 1 ～ 2 1H,1H,2H,2H- , 3 ～ 4 , , , , ,1H,1H,2H,2H- 1H,1H,2H,2H- ,1H,1H,2H,2H- 1H,1H,2H,2H- 0.55 ～ 0.65mM. </xnotran>
In the step 3), the solvent is a mixture of ethanol and isopropanol, and the ratio of ethanol to isopropanol in the solvent is (1-2): 1.
in the step 3), ethanol is used for cleaning.
In the technical scheme, the rotating speed of the centrifugation is 4000-6000 rpm, and the time of the centrifugation is 4-6 min.
The super-hydrophobic nano-porous silver-based material obtained by the preparation method.
The application of the material based on the super-hydrophobic nano-porous silver as an electrocatalyst in preparation of ammonia by nitrogen reduction is disclosed.
In the technical scheme, the highest ammonia yield can reach (34.18 +/-2.24) mu g.h -1 ·cm -2 The maximum Faraday efficiency reaches 29.9 percent.
The method for synthesizing the material based on the super-hydrophobic nano-porous silver by using the chemical method has the advantages of simple and easy reaction operation, simple required equipment and high repeatability, and the prepared material based on the super-hydrophobic nano-porous silver has the advantages of high yield, good electrochemical stability, excellent nitrogen reduction electro-catalysis performance and the like, and can be widely applied to the field of ammonia electro-catalysis synthesis.
Drawings
FIG. 1 (a) is a scanning electron microscope characterization of AgCl cubic particles obtained in example 1;
FIG. 1 (b) is a transmission electron microscope characterization diagram of the nano-porous silver material obtained in example 1 (the inset is its enlarged view);
FIG. 2 is a graph of the UV-visible absorption spectrum of the nano-porous silver material obtained in example 1 and a super-hydrophobic nano-porous silver-based material, wherein "porous silver" is the nano-porous silver material and "super-hydrophobic porous silver" is the super-hydrophobic nano-porous silver-based material;
FIG. 3 is an X-ray powder diffraction characterization chart of the nano-porous silver material obtained in example 1 and a super-hydrophobic nano-porous silver material, wherein the 'porous silver' is the nano-porous silver material, and the 'super-hydrophobic porous silver' is the super-hydrophobic nano-porous silver material;
FIG. 4 is a graph showing the static water contact angle characteristics of the nanoporous silver material and the superhydrophobic-based nanoporous silver material obtained in example 1, wherein the "porous silver" is the nanoporous silver material, and the "superhydrophobic porous silver" is the superhydrophobic nanoporous silver-based material;
FIG. 5 is a distribution diagram of Ag and F elements based on the super-hydrophobic nano-porous silver material obtained in example 1;
FIG. 6 is a chronoamperometric test chart based on the superhydrophobic nanoporous silver material obtained in example 1;
fig. 7 is a graph of ammonia yield and ammonia production efficiency based on the superhydrophobic nanoporous silver material obtained in example 1.
Detailed Description
The preparation method of the superhydrophobic nanoporous silver-based material of the invention is described in detail below with reference to the accompanying drawings.
Polyvinylpyrrolidone (PVP, average molecular weight 130,000, purity more than or equal to 99%) purchased from Shanghai leaf biology, inc.; silver nitrate (purity is more than or equal to 99%) is purchased from Beijing Bailingwei science and technology Limited; sodium borohydride (purity is more than or equal to 99%) purchased from Yueli chemical Co., ltd in Tianjin; ethylene glycol (analytically pure), acetone (analytically pure) and concentrated hydrochloric acid (purity of 36-38%) purchased from Tianjin Feng ship chemical reagent science and technology Limited; ethanol (analytical grade), isopropanol (analytical grade), available from tianjin Dalocou chemical trade company; concentrated ammonia (25 wt% strength) was purchased from Tianjin Komion Chemicals, inc. 1H, 2H-Perfluorodecylthiol (PFDT) is available from Shanghai Allantin Biotechnology Ltd.
The cleaning in the following examples was: centrifuging, removing the supernatant, dissolving the lower precipitate in a washing solvent, centrifuging, and removing the supernatant again.
Example 1
A preparation method based on a super-hydrophobic nano-porous silver material comprises the following steps:
1) Mixing a polyvinylpyrrolidone aqueous solution and 20mL of a silver nitrate aqueous solution, transferring the mixture into a round-bottomed flask, stirring the mixture at the room temperature of 20-25 ℃ for 10 minutes at the speed of 450rpm to uniformly mix the polyvinylpyrrolidone aqueous solution and the silver nitrate aqueous solution, dripping hydrochloric acid into the round-bottomed flask, stirring the mixture at the room temperature for 20 minutes until the liquid color is changed from colorless transparency to white, centrifuging the mixture at 5000rpm for 5 minutes to obtain a solid, sequentially washing the solid with water and ethanol, and drying the solid at the vacuum environment of 40 ℃ for 2 hours to obtain white solid AgCl cubic particles, wherein the ratio of the polyvinylpyrrolidone in the polyvinylpyrrolidone aqueous solution, the silver nitrate in the silver nitrate aqueous solution and the HCl in the hydrochloric acid is 3.08 multiplied by 10 according to the parts of the substance -4 :2.35:4.52×10 -4 (ii) a The concentration of the polyvinylpyrrolidone in the polyvinylpyrrolidone aqueous solution is 0.2mg/mL, the concentration of the silver nitrate in the silver nitrate aqueous solution is 0.2mg/mL, and the concentration of HCl in hydrochloric acid is 6mol/L.
2) Firstly, uniformly mixing 50mg of AgCl cubic particles and 5mL of water, then adding 45mL of ethylene glycol, stirring at room temperature at 500rpm for 30 seconds to obtain an AgCl cubic particle solution, dropwise adding 1mL of sodium borohydride aqueous solution into the AgCl cubic particle solution, stirring for 30 minutes until the solution gradually changes from white to grey-black, adding 4mL of ammonia water (the concentration of the ammonia water is 25 wt%), stirring at 600rpm for 2 minutes, then adding 5mL of acetone, centrifuging at 5500rpm for 5 minutes to obtain a precipitate after centrifugation, washing the precipitate with ethanol for 3 times, and drying at 40 ℃ for 1 hour in a vacuum environment to obtain a nano porous silver material, wherein the ratio of the AgCl cubic particles to the sodium borohydride aqueous solution is 52 in parts by mass, and the concentration of sodium borohydride in the sodium borohydride aqueous solution is 20mg/mL, and the method for preparing the sodium borohydride aqueous solution comprises the following steps: sodium borohydride was mixed with water under ice bath conditions (0 ℃) to give an aqueous sodium borohydride solution.
3) Uniformly mixing 4mg of nano-porous silver material and 2mL of solvent to obtain a reaction solution, dropwise adding 1mL of 1H,2H and 2H-perfluorodecyl mercaptan ethanol solution into the reaction solution, stirring for reaction for 4 hours, centrifuging at 5000rpm for 5 minutes to obtain a first precipitate, mixing the first precipitate with 2mL of solvent, dropwise adding 1mL of 1H,2H and 2H-perfluorodecyl mercaptan ethanol solution again, stirring for reaction for 4 hours, centrifuging at 5000rpm for 5 minutes to obtain a second precipitate, washing the second precipitate with ethanol for 2 times, and drying at 40 deg.C under vacuum for 2 hr to obtain the final product based on the superhydrophobic nanoporous silver material, wherein the ethanol solution of 1H, 2H-perfluorodecyl mercaptan is a mixture of 1H, 2H-perfluorodecyl mercaptan (PFDT) and ethanol, the concentration of 1H, 2H-perfluorodecyl mercaptan in the 1H, 2H-perfluorodecyl mercaptan ethanol solution is 0.6mM, the solvent is a mixture of ethanol and isopropanol, and the ratio of ethanol to isopropanol in the solvent is 1.
The dimensions of the superhydrophobic nanoporous silver-based material obtained in example 1 were: (340 +/-18) nm; the surface of the nano-porous silver material is provided with bulges, channels are formed between every two adjacent bulges, and the size of the nano-porous silver material is (218 +/-14) nm. The diffraction peaks are: 38.0 degrees, 44.6 degrees and 64.6 degrees, and the water contact angles of the nano-porous silver material and the super-hydrophobic nano-porous silver material are respectively (18.7 +/-0.5) ° and (123.0 +/-0.4).
Example 2
A preparation method based on a super-hydrophobic nano-porous silver material comprises the following steps:
1) Mixing a polyvinylpyrrolidone aqueous solution and 20mL of a silver nitrate aqueous solution, transferring the mixture into a round-bottomed flask, stirring the mixture at the room temperature of 20-25 ℃ for 10 minutes at the speed of 450rpm to uniformly mix the polyvinylpyrrolidone aqueous solution and the silver nitrate aqueous solution, dripping hydrochloric acid into the round-bottomed flask, stirring the mixture at the room temperature for 20 minutes until the liquid color is changed from colorless transparency to white, centrifuging the mixture at 5000rpm for 5 minutes to obtain a solid, sequentially washing the solid with water and ethanol, and drying the solid at the vacuum environment of 40 ℃ for 2 hours to obtain white solid AgCl cubic particles, wherein the ratio of the polyvinylpyrrolidone in the polyvinylpyrrolidone aqueous solution, the silver nitrate in the silver nitrate aqueous solution and the HCl in the hydrochloric acid is 3.08 multiplied by 10 according to the parts of the substance -4 :2.35:4.52×10 -4 (ii) a The concentration of the polyvinylpyrrolidone in the polyvinylpyrrolidone aqueous solution is 0.2mg/mL, the concentration of the silver nitrate in the silver nitrate aqueous solution is 0.2mg/mL, and the concentration of HCl in hydrochloric acid is 6mol/L.
2) Firstly, uniformly mixing 50mg of AgCl cubic particles and 5mL of water, then adding 45mL of ethylene glycol, stirring at room temperature at 500rpm for 30 seconds to obtain an AgCl cubic particle solution, dropwise adding 1.25mL of sodium borohydride aqueous solution into the AgCl cubic particle solution, stirring for 20 minutes until the solution gradually changes from white to grey-black, adding 4mL of ammonia water (the concentration of the ammonia water is 25 wt%), stirring at 600rpm for 2 minutes, then adding 5mL of acetone, centrifuging at 5500rpm for 5 minutes to obtain a precipitate after centrifugation, washing the precipitate for 3 times by using ethanol, and drying at 40 ℃ for 1 hour in a vacuum environment to obtain a nano porous silver material, wherein the ratio of the AgCl cubic particles to the sodium borohydride aqueous solution is 5mg/mL and the concentration of the sodium borohydride in the sodium borohydride aqueous solution is 20mg/mL according to parts by mass: sodium borohydride was mixed with water under ice bath conditions (0 ℃) to give an aqueous sodium borohydride solution.
3) Uniformly mixing 4mg of nano-porous silver material and 2mL of solvent to obtain a reaction solution, dropwise adding 1mL of 1H,2H and 2H-perfluorodecyl mercaptan ethanol solution into the reaction solution, stirring for reaction for 4 hours, centrifuging at 5000rpm for 5 minutes to obtain a first precipitate, mixing the first precipitate with 2mL of solvent, dropwise adding 1mL of 1H,2H and 2H-perfluorodecyl mercaptan ethanol solution again, stirring for reaction for 4 hours, centrifuging at 5000rpm for 5 minutes to obtain a second precipitate, washing the second precipitate with ethanol for 2 times, and drying at 40 deg.C under vacuum for 2 hr to obtain the final product based on the superhydrophobic nanoporous silver material, wherein the ethanol solution of 1H, 2H-perfluorodecyl mercaptan is a mixture of 1H, 2H-perfluorodecyl mercaptan (PFDT) and ethanol, the concentration of 1H, 2H-perfluorodecyl mercaptan in the 1H, 2H-perfluorodecyl mercaptan ethanol solution is 0.6mM, the solvent is a mixture of ethanol and isopropanol, and the ratio of ethanol to isopropanol in the solvent is 1.
The size of the super-hydrophobic nano-porous silver-based material obtained in example 2 is as follows: (340 +/-18) nm; the surface of the nano-porous silver material is provided with bulges, channels are formed between every two adjacent bulges, and the size of the nano-porous silver material is (175 +/-8) nm. The diffraction peaks are: 38.0 degrees, 44.6 degrees and 64.6 degrees, and the water contact angles of the nano-porous silver material and the super-hydrophobic nano-porous silver material are respectively (18.7 +/-0.5) ° and (123.0 +/-0.4) °.
Example 3
A preparation method based on a super-hydrophobic nano-porous silver material comprises the following steps:
1) Mixing a polyvinylpyrrolidone aqueous solution and 20mL of a silver nitrate aqueous solution, transferring the mixture into a round-bottomed flask, stirring the mixture at the room temperature of 20-25 ℃ for 10 minutes at the speed of 450rpm to uniformly mix the polyvinylpyrrolidone aqueous solution and the silver nitrate aqueous solution, dripping hydrochloric acid into the round-bottomed flask, stirring the mixture at the room temperature for 20 minutes until the liquid color is changed from colorless transparency to white, centrifuging the mixture at 5000rpm for 5 minutes to obtain a solid, sequentially washing the solid with water and ethanol, and drying the solid at the vacuum environment of 40 ℃ for 2 hours to obtain white solid AgCl cubic particles, wherein the ratio of the polyvinylpyrrolidone in the polyvinylpyrrolidone aqueous solution, the silver nitrate in the silver nitrate aqueous solution and the HCl in the hydrochloric acid is 3.08 multiplied by 10 according to the parts of the substance -4 :2.35:4.52×10 -4 (ii) a The concentration of the polyvinylpyrrolidone in the polyvinylpyrrolidone aqueous solution is 0.2mg/mL, the concentration of the silver nitrate in the silver nitrate aqueous solution is 0.2mg/mL, and the concentration of HCl in hydrochloric acid is 6mol/L.
2) Firstly, uniformly mixing 50mg of AgCl cubic particles and 5mL of water, then adding 45mL of ethylene glycol, stirring at 500rpm for 30 seconds at room temperature to obtain an AgCl cubic particle solution, dropwise adding 1.5mL of sodium borohydride aqueous solution into the AgCl cubic particle solution, stirring for 20 minutes until the solution gradually becomes grey-black from white, adding 4mL of ammonia water (the concentration of the ammonia water is 25 wt%), stirring at 600rpm for 2 minutes, then adding 5mL of acetone, centrifuging at 5500rpm for 5 minutes to obtain a precipitate after centrifugation, washing the precipitate with ethanol for 3 times, and drying at 40 ℃ for 1 hour in a vacuum environment to obtain a nano porous silver material, wherein the ratio of the AgCl cubic particles to the sodium borohydride aqueous solution is 52, the concentration of sodium borohydride in the sodium borohydride aqueous solution is 20mg/mL, and the method for preparing the sodium borohydride aqueous solution comprises the following steps: sodium borohydride was mixed with water under ice bath conditions (0 ℃) to give an aqueous sodium borohydride solution.
3) Uniformly mixing 4mg of nano-porous silver material and 2mL of solvent to obtain a reaction solution, dropwise adding 1mL of 1H,2H and 2H-perfluorodecyl mercaptan ethanol solution into the reaction solution, stirring for reaction for 4 hours, centrifuging at 5000rpm for 5 minutes to obtain a first precipitate, mixing the first precipitate with 2mL of solvent, dropwise adding 1mL of 1H,2H and 2H-perfluorodecyl mercaptan ethanol solution again, stirring for reaction for 4 hours, centrifuging at 5000rpm for 5 minutes to obtain a second precipitate, washing the second precipitate with ethanol for 2 times, and drying at 40 deg.C under vacuum for 2 hr to obtain the final product based on the superhydrophobic nanoporous silver material, wherein the ethanol solution of 1H, 2H-perfluorodecyl mercaptan is a mixture of 1H, 2H-perfluorodecyl mercaptan (PFDT) and ethanol, the concentration of 1H, 2H-perfluorodecyl mercaptan in the 1H, 2H-perfluorodecyl mercaptan ethanol solution is 0.6mM, the solvent is a mixture of ethanol and isopropanol, and the ratio of ethanol to isopropanol in the solvent is 1.
The dimensions of the superhydrophobic nanoporous silver-based material obtained in example 3 were: (340 +/-18) nm; the surface of the nano-porous silver material is provided with bulges, pore channels are formed between every two adjacent bulges, and the size of the nano-porous silver material is (82 +/-5) nm. The diffraction peaks are: 38.0 degrees, 44.6 degrees and 64.6 degrees, and the water contact angles of the nano-porous silver material and the super-hydrophobic nano-porous silver material are respectively (18.7 +/-0.5) ° and (123.0 +/-0.4) °.
Example 4
A preparation method based on a super-hydrophobic nano-porous silver material comprises the following steps:
1) Mixing polyvinylpyrrolidone aqueous solution and 20mL of silver nitrate aqueous solution, transferring the mixture into a round-bottomed flask, stirring the mixture at the room temperature of 20-25 ℃ for 10 minutes at the speed of 450rpm to uniformly mix the polyvinylpyrrolidone aqueous solution and the silver nitrate aqueous solution, dripping hydrochloric acid into the round-bottomed flask, stirring the mixture at the room temperature for 20 minutes until the liquid color is changed from colorless transparency to white, centrifuging the mixture at the speed of 5000rpm for 5 minutes to obtain a solid, and sequentially using water and the silver nitrate aqueous solution to sequentially obtain a solidWashing the solid with ethanol, and drying at 40 deg.C for 2 hr to obtain AgCl cubic particles as white solid, wherein the ratio of polyvinylpyrrolidone in polyvinylpyrrolidone aqueous solution to silver nitrate in silver nitrate aqueous solution and HCl in hydrochloric acid is 3.08 × 10 -4 :2.35:4.52×10 -4 (ii) a The concentration of the polyvinylpyrrolidone in the polyvinylpyrrolidone aqueous solution is 0.2mg/mL, the concentration of the silver nitrate in the silver nitrate aqueous solution is 0.2mg/mL, and the concentration of the HCl in the hydrochloric acid is 6mol/L.
2) Firstly, uniformly mixing 50mg of AgCl cubic particles and 5mL of water, then adding 45mL of ethylene glycol, stirring at room temperature at 500rpm for 30 seconds to obtain an AgCl cubic particle solution, dropwise adding 1mL of sodium borohydride aqueous solution into the AgCl cubic particle solution, stirring for 20 minutes until the solution gradually changes from white to grey-black, adding 4mL of ammonia water (the concentration of the ammonia water is 25 wt%), stirring at 600rpm for 2 minutes, then adding 5mL of acetone, centrifuging at 5500rpm for 5 minutes to obtain a precipitate after centrifugation, washing the precipitate with ethanol for 3 times, and drying at 40 ℃ for 1 hour in a vacuum environment to obtain a nano porous silver material, wherein the ratio of the AgCl cubic particles to the sodium borohydride aqueous solution is 52 in parts by mass, and the concentration of sodium borohydride in the sodium borohydride aqueous solution is 20mg/mL, and the method for preparing the sodium borohydride aqueous solution comprises the following steps: sodium borohydride was mixed with water under ice bath conditions (0 ℃) to give an aqueous sodium borohydride solution.
3) Uniformly mixing 4mg of nano-porous silver material and 2mL of solvent to obtain a reaction solution, dropwise adding 1mL of 1H,2H and 2H-perfluorodecyl mercaptan ethanol solution into the reaction solution, stirring for reaction for 4 hours, centrifuging at 5000rpm for 5 minutes to obtain a first precipitate, mixing the first precipitate with 2mL of solvent, dropwise adding 1mL of 1H,2H and 2H-perfluorodecyl mercaptan ethanol solution again, stirring for reaction for 4 hours, centrifuging at 5000rpm for 5 minutes to obtain a second precipitate, washing the second precipitate with ethanol for 2 times, and drying at 40 deg.C under vacuum for 2 hr to obtain the final product based on the superhydrophobic nanoporous silver material, wherein the ethanol solution of 1H, 2H-perfluorodecyl mercaptan is a mixture of 1H, 2H-perfluorodecyl mercaptan (PFDT) and ethanol, the concentration of 1H, 2H-perfluorodecyl mercaptan in the 1H, 2H-perfluorodecyl mercaptan ethanol solution is 0.6mM, the solvent is a mixture of ethanol and isopropanol, and the ratio of ethanol to isopropanol in the solvent is 1.
The dimensions of the superhydrophobic nanoporous silver-based material obtained in example 4 were: (340 +/-18) nm; the surface of the nano-porous silver material is provided with bulges, channels are formed between every two adjacent bulges, and the size of the nano-porous silver material is (109 +/-11) nm. The diffraction peaks are: 38.0 degrees, 44.6 degrees and 64.6 degrees, and the water contact angles of the nano-porous silver material and the super-hydrophobic nano-porous silver material are respectively (18.7 +/-0.5) ° and (123.0 +/-0.4) °.
The super-hydrophobic nano-porous silver-based material obtained in example 1 was taken for further characterization:
(1) Characterization of electron microscopy morphology
Selecting 1mg of AgCl cubic particles obtained in example 1, dispersing the AgCl cubic particles in 1mL of ethanol to obtain a first sample solution, dripping 5 mu L of the first sample solution on a silicon wafer (sold by electron microscope company), and displaying scanning electron imaging under the action of a scanning electron microscope electron beam, wherein the model of the instrument is JEOL JSM-6700F, and is shown in figure 1 (a), and the shape and the size of the AgCl cubic particles are represented.
1mg of the nano-porous silver material obtained in the example 1 is dispersed in 1mL of ethanol to obtain a second sample solution, 5 muL of the second sample solution is respectively dripped on a copper mesh (sold by electron microscope companies) by using a pipette, and transmission electron imaging is performed under the action of a transmission electron microscope electron beam, wherein the model of the instrument is Tecnai F20, and the appearance and the size of the nano-porous silver material are represented as shown in a figure 1 (b).
As can be seen from FIG. 1 (a), the AgCl cubic particles have a solid cubic morphology and a size of (340. + -.18) nm. From the step 1 (b), the nano-porous silver material is a three-dimensional porous hollow structure, has an internal hollow structure and a large number of mutually communicated pore channels, and has pore channels on the surface thereof to form a three-dimensional structure, thereby providing a large number of catalytic active sites, and the size of the nano-porous silver material is (218 +/-14) nm.
(2) Characterization of absorption spectra
The nano-porous silver material obtained in the example 1 and the super-hydrophobic nano-porous silver material are subjected to further drying treatment: after drying at 60 ℃ for 12 hours, 0.5mg of the dried nanoporous silver material obtained in example 1 and the superhydrophobic nanoporous silver-based material were dissolved in 3.5mL of ethanol, respectively, and subjected to UV-visible spectrum testing (instrument model: mapada V-1200): the nanometer porous silver material shows characteristic local surface plasmon resonance peak at 395nm, and the super-hydrophobic nanometer porous silver material shows characteristic local surface plasmon resonance peak at 403nm, which proves that PFDT is added to be successfully synthesized with simple substance silver. See fig. 2.
(3) Nanoporous silver materials and X-ray powder diffraction (PXRD) characterization based on superhydrophobic nanoporous silver materials
As shown in FIG. 3 (instrument model: bruker GADDS XRD), comparing PXRD graphs of the nano-porous silver material and the super-hydrophobic nano-porous silver material, PXRD characterization based on the super-hydrophobic nano-porous silver material shows that the nano-porous silver material has reliable phase purity, and characteristic diffraction peaks are displayed at 38.0 degrees, 44.6 degrees and 64.6 degrees, thereby proving successful combination of the nano-porous silver material and the super-hydrophobic material PFDT. The structural characterization provides assurance for its use as an electrocatalyst.
(4) Characterization of hydrophobicity
As shown in FIG. 4, 1H, 2H-Perfluorodecylthiol (PFDT) acts as a hydrophobic barrier, preventing water from entering hydrogen evolution. The water contact angles of the nano porous silver material and the super-hydrophobic nano porous silver material are respectively (18.7 +/-0.5) ° and (123.0 +/-0.4) ° so as to show the good hydrophobic property of the super-hydrophobic nano porous silver material. The hydrophobic electrode surface can effectively inhibit HER and create abundant three-phase contact points for reactants.
(5) X-ray energy spectrum (EDS) image based on super-hydrophobic nano-porous silver material
As shown in FIG. 5 (model: tecnai F20), the element distribution and composition based on the superhydrophobic nanoporous silver material were determined using X-ray energy spectroscopy (EDS) analysis. EDS atlas shows that Ag and F are evenly distributed, and the element distribution ratio of Ag and F is as follows: 99.5; the composite material is still in a three-dimensional structure with hollow and porous channels inside, and the F element is uniformly attached to the surface of the porous channels, so that the successful combination of the hydrophobic substance PFDT and the nano-porous silver is proved, and the original appearance of the composite material is not changed.
(6) Characterization of Nitrogen reduction catalysis Performance
The glassy carbon electrode is sequentially subjected to ultrasonic cleaning by dilute nitric acid, acetone and ethanol, 4mg of the super-hydrophobic nano-porous silver-based material prepared in example 1 is dried at 60 ℃ for 12 hours, then dissolved in 1mL of ethanol, 4 mu L of the material is dropwise added onto the glassy carbon electrode by using a pipette, and the material is dried at 60 ℃ in vacuum for 1 hour and then used as a working electrode. Ag/AgCl (model: R0305 available from Tianjin Elatan Cheng technology development Co., ltd.) as reference electrode and platinum sheet as counter electrode, and placing in a container with 0.1MNa 2 SO 4 Na of (2) 2 SO 4 Introducing nitrogen into an electrode pool of aqueous solution (serving as electrolyte), and introducing Na before the electrocatalytic reaction is started 2 SO 4 And introducing nitrogen into the aqueous solution for at least half an hour to remove impurity gases in the electrolyte so as to keep the electrolyte in a nitrogen saturated state. Then, a constant current method test (M. -M.Shi, D.Bao, B. -R.Wulan, Y. -H.Li, Y. -F.Zhang, J. -M.Yan, Q.Jiang, adv.Mater.2017,29, 1606550.) was performed using an electrochemical workstation, wherein the voltages in the test were-1.1V, -1.0V, -0.9V, -0.8V, -0.7V (vs RHE, reversible hydrogen electrode) respectively, and the time was 2 hours, and the introduction of nitrogen gas was maintained during the test. Wherein the conversion formula of the voltage value compared with the reversible hydrogen electrode is E (vs RHE) = E (vs Ag/AgCl) +0.0592 pH + 0.1976). (E (vs RHE) is the relative voltage of the working electrode compared to the reversible hydrogen electrode, E (vs Ag/AgCl) is the relative voltage of the working electrode compared to the reference electrode Ag/AgCl, and pH is the pH of the electrolyte). After the test for 2 hours is finished, taking 2mL of the reacted electrolyte to perform an indophenol blue spectrophotometry to perform ammonia concentration test and calculate the yield of ammonia and the ammonia production efficiency. See FIGS. 6 and 7 (model: shanghai Chen Hua CHI 760E).
As can be seen from fig. 6, the current remained substantially constant in the 2-hour constant current test, demonstrating the stability of the superhydrophobic nanoporous silver-based material as an electrocatalyst, and from this current value the faraday efficiency was further calculated, see fig. 7. As shown in FIG. 7, when the superhydrophobic nano-porous silver-based material is used as an electrode, the ammonia production reaction by nitrogen reduction can achieve a high ammonia yield (34.18 +/-2.24) mu g.h –1 ·cm –2 Faraday's efficiency (29.9%), greatly breaking through traditional noble goldBelongs to the electrode material<10% efficiency.
The method for carrying out ammonia concentration test and calculating the yield and the ammonia production efficiency of ammonia by performing indophenol blue spectrophotometry comprises the following steps:
1. preparing a solution A, a solution B and a solution C, wherein the solution A is a mixture of NaOH, salicylic acid and water, the concentration of the NaOH in the solution A is 1M, and the mass fraction of the salicylic acid in the solution A is 5%;
the solution B is NaClO aqueous solution with NaClO concentration of 0.05M;
the solution C is C 5 FeN 6 Na 2 C with 1% of O by mass 5 FeN 6 Na 2 And (4) O aqueous solution.
Establishing ammonia concentration-absorbance standard curve, and adding 2mL of ammonium chloride into 10 20mL glass bottles respectively, wherein the ammonium chloride concentration is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09 and 0.10 mmol.L -1 Then, 2mL of the solution A, 1mL of the solution B and 0.2mL of the solution C were added to each glass bottle in this order, and after standing and reacting at room temperature for two hours, a mixed solution was obtained, and the concentration of ammonium chloride in the ammonium chloride aqueous solution (0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10 mmol. L) was measured by measuring the absorption spectrum of the mixed solution using an ultraviolet-visible spectrometer -1 ) And absorbance of the peak of the absorption spectrum, y (absorbance) =0.07021+6.5520x (x: concentration of ammonium chloride in an ammonium chloride aqueous solution).
2. Respectively adding 2mL of solution A, 1mL of solution B and 0.2mL of solution C into a 20mL glass bottle containing 2mL of reacted electrolyte, standing at room temperature for reaction for two hours, measuring the absorption spectrum by using an ultraviolet-visible spectrometer, substituting the absorbance of the peak value of the absorption spectrum as y into a standard function curve, and measuring the value of x as the concentration C of ammonia NH3 Then by the formula
The yield of the ammonia was calculated and,
calculating the efficiency of ammonia production, i.e. faradThe first efficiency. Wherein v is NH3 As a yield of ammonia, c NH3 For the ammonia concentration obtained by the standard function curve, V is the volume of the electrolyte after the reaction (200 mL), t is the duration of the galvanostatic test, A cat. Is based on the area (0.07065 cm) of the super-hydrophobic nano-porous silver material 2 ) F is a Faraday constant, and I is a current value in a constant current method test.
According to the characterization results, the obtained super-hydrophobic nano-porous silver material-based electrocatalyst is in a porous hollow structure and a spheroid nanoparticle shape, and consists of a main body nano-porous silver material and 1H, 2H-perfluorodecyl mercaptan (PFDT). The main body nano-porous silver material is a three-dimensional porous hollow structure, and the size of the embodiment 1 is (340 +/-18) nm. The distribution ratio of Ag to F elements in the super-hydrophobic nano-porous silver material is as follows: 99.5:0.5. The diffraction peak of the main body nano-porous silver material and the composite material show characteristic diffraction peaks at 38.0 degrees, 44.6 degrees and 64.6 degrees, and the crystal structures of the main body nano-porous silver material and the composite material are proved. In the electrochemical nitrogen reduction reaction, the content of the super-hydrophobic nano porous silver material reaches (34.18 +/-2.24) mu g.h in two hours -1 ·cm -2 Ammonia yield and faradaic efficiency of 29.9%, demonstrating its excellent electrocatalytic properties.
The patent is completed under the subsidies of natural science fund (19 JCQNJC 05000) and national natural science fund (Grant No. 22005220) in Tianjin.
The invention has been described in an illustrative manner, and it is to be understood that any simple variations, modifications or other equivalent changes which can be made by one skilled in the art without departing from the spirit of the invention fall within the scope of the invention.
Claims (10)
1. A preparation method based on a super-hydrophobic nano-porous silver material is characterized by comprising the following steps:
1) Uniformly mixing a polyvinylpyrrolidone aqueous solution and a silver nitrate aqueous solution, dripping hydrochloric acid, stirring until the color of the liquid is changed from colorless transparency to white, centrifuging to obtain a solid, sequentially washing the solid with water and ethanol, and drying to obtain the polyvinylpyrrolidone/silver nitrate aqueous solutionThe white solid is AgCl cubic particles, wherein the ratio of polyvinylpyrrolidone in polyvinylpyrrolidone aqueous solution to silver nitrate in silver nitrate aqueous solution to HCl in hydrochloric acid is (3 × 10) in parts by weight -4 ～4×10 -4 ):2.35:(4×10 -4 ～5×10 -4 )；
2) Uniformly mixing 40-60 parts by mass of AgCl cubic particles, 4.5-5.5 parts by volume of water and 40-50 parts by volume of ethylene glycol to obtain an AgCl cubic particle solution, dropwise adding 1-2 parts by volume of sodium borohydride aqueous solution into the AgCl cubic particle solution, stirring until the solution gradually turns from white to grey black, adding 4-5 parts by volume of ammonia water, stirring for 1-2 min, adding 4-5 parts by volume of acetone, centrifuging to obtain a precipitate, cleaning the precipitate, and drying to obtain the nano porous silver material, wherein when the unit of the mass parts is mg, the unit of the volume parts is mL, and the ratio of the AgCl cubic particles to the sodium borohydride aqueous solution is (4-6): 2;
3) <xnotran> 4 ～ 5 1 ～ 2 , , 1 ～ 2 1H,1H,2H,2H- , 3 ～ 4 , , 1 ～ 2 , 1 ～ 2 1H,1H,2H,2H- , 3 ～ 4 , , , , ,1H,1H,2H,2H- 1H,1H,2H,2H- ,1H,1H,2H,2H- 1H,1H,2H,2H- 0.55 ～ 0.65mM. </xnotran>
2. The preparation method according to claim 1, wherein in the step 1), the aqueous solution of polyvinylpyrrolidone and the aqueous solution of silver nitrate are mixed and stirred at a speed of 400 to 500rpm for 10 to 15 minutes at a room temperature of 20 to 25 ℃ to uniformly mix the aqueous solution of polyvinylpyrrolidone and the aqueous solution of silver nitrate.
3. The method according to claim 2, wherein in the step 1), the concentration of the polyvinylpyrrolidone in the aqueous solution of the polyvinylpyrrolidone is 0.1 to 0.3mg/mL, the concentration of the silver nitrate in the aqueous solution of the silver nitrate is 0.15 to 0.25mg/mL, and the concentration of the HCl in the hydrochloric acid is 5.5 to 6.5mol/L.
4. The method according to claim 1, wherein in the step 2), the concentration of sodium borohydride in the aqueous sodium borohydride solution is 10 to 20mg/mL, and the method for preparing the aqueous sodium borohydride solution comprises: and mixing sodium borohydride with water under an ice bath condition to obtain the sodium borohydride aqueous solution.
5. The preparation method according to claim 1, wherein in the step 2), the method for uniformly mixing the AgCl cubic particles, the water and the ethylene glycol comprises the following steps: firstly, uniformly mixing AgCl cubic particles with water, then adding the ethylene glycol, and stirring for 20-30 seconds;
in the step 2), the stirring time for gradually changing the solution from white to grey black is 20-30 minutes;
in the step 2), washing the precipitate by using ethanol;
in the step 2), the stirring speed is 500-600 rpm;
in the step 2), the concentration of the ammonia water is 25 to 28wt%.
6. The preparation method of claim 1, wherein the drying is performed in a vacuum environment, the drying temperature is 30-40 ℃, the drying time is 1-3 hours, the rotation speed of the centrifugation is 4000-6000 rpm, and the centrifugation time is 4-6 min.
7. The preparation method according to claim 1, wherein in the step 3), the solvent is a mixture of ethanol and isopropanol, and the ratio of ethanol to isopropanol in the solvent is (1-2): 1;
in the step 3), ethanol is used for cleaning.
8. The superhydrophobic nanoporous silver-based material obtained by the preparation method according to any one of claims 1 to 7.
9. Use of the superhydrophobic nanoporous silver-based material of claim 8 as an electrocatalyst for the preparation of ammonia by reduction in nitrogen.
10. Use according to claim 9, characterized in that the ammonia yield is up to 31-37 μ g-h -1 ·cm -2 The maximum Faraday efficiency reaches 29.9 percent.
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| CN108517540A (en) * | 2018-04-11 | 2018-09-11 | 东莞理工学院 | Porous silver and preparation method thereof, silver powder and its application |
| CN109096766A (en) * | 2018-08-06 | 2018-12-28 | 青岛科技大学 | A kind of preparation method of gold nanoparticle Composite silicone resin |
| CN110125434A (en) * | 2019-05-14 | 2019-08-16 | 东南大学 | A kind of preparation method of photo-thermal gold nano-material |
| CN112316981A (en) * | 2019-07-19 | 2021-02-05 | 天津师范大学 | Composite material based on nano porous gold and zeolite imidazole framework and preparation method and application thereof |
| CN114068950A (en) * | 2020-08-03 | 2022-02-18 | 天津师范大学 | Ultrafine sub-nano gold composite material electrocatalyst based on porous carbon support and preparation method and application thereof |
| CN113245554A (en) * | 2021-04-21 | 2021-08-13 | 中山大学 | Silver porous material and preparation method thereof |
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