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CN-122011417-A - Iron-modified hydroxyl-enriched metal organic framework material, preparation method thereof and application of iron-modified hydroxyl-enriched metal organic framework material in preparing ammonia through electrocatalytic nitrate reduction

CN122011417ACN 122011417 ACN122011417 ACN 122011417ACN-122011417-A

Abstract

The invention discloses an iron-modified hydroxyl-enriched metal organic frame material, a preparation method thereof and application of electrocatalytic nitrate radical reduction to ammonia, wherein the invention adopts a hydroxyl-containing pyrenyl organic ligand to construct the hydroxyl-enriched metal organic frame material, and utilizes the chelation of hydroxyl and iron ions to introduce an iron catalytic active center by a simple method to construct an electrocatalyst with definite, efficient and green structure; the method has the advantages that the steps from ligand synthesis to electrocatalyst synthesis are simple and convenient, the period is short, the cost is low, the production time and the cost are effectively saved, the prepared metal organic framework material has highly dispersed catalytic active centers, the efficient reduction of nitrate radical into ammonia is realized in electrolyte, the yield is 17.82mg/h/mg cat , the Faraday efficiency reaches 90 percent, and the cycle performance is excellent.

Inventors

  • HE JUN
  • Xie Zexiang

Assignees

  • 广东工业大学

Dates

Publication Date
20260512
Application Date
20260309

Claims (10)

  1. 1. An iron-modified hydroxyl-enriched metal organic framework material is characterized in that, Comprises a metal organic framework NU-1000-OH formed by coordination of carboxyl in a structural ligand shown in a formula I and Zr 4+ , and an iron ion coordinated with hydroxyl on the structural ligand shown in the formula I in NU-1000-OH;
  2. 2. the iron modified hydroxyl-rich metalorganic framework material of claim 1, wherein, Zr 4+ forms Zr 6 metal clusters, each Zr 6 metal cluster is coordinately connected with one carboxyl group in each ligand of eight structural ligands shown in formula I, two oxygen atoms of the carboxyl group in each structural ligand shown in formula I are coordinately connected with one axial zirconium and equatorial zirconium in each Zr 6 metal cluster respectively, each equatorial zirconium coordinately connected with two structural ligands shown in formula I, and each axial zirconium coordinately connected with four structural ligands shown in formula I.
  3. 3. A method of preparing the iron modified hydroxyl-rich metal organic framework material of claim 1 or 2, comprising the steps of: and carrying out modification reaction on the metal organic frameworks NU-1000-OH and ferric ion salt in a first solvent to obtain the iron modified hydroxyl-rich metal organic framework material.
  4. 4. The method for preparing the iron-modified hydroxyl-rich metal organic framework material according to claim 3, wherein the method comprises the steps of, The ferric ion salt is any one of ferric hydrochloride, ferric sulfate, ferric nitrate, ferric acetate or ferric hydrate; The mass ratio of NU-1000-OH to ferric ion salt is 1 (1.5-2.5).
  5. 5. The method for preparing the iron-modified hydroxyl-rich metal organic framework material according to claim 3, wherein the method comprises the steps of, The first solvent is N, N-diethyl formamide, and the mass volume ratio of NU-1000-OH to N, N-diethyl formamide is 1mg (0.1-1) mL; the temperature of the modification reaction is 90-120 ℃, and the reaction time is 12-48h.
  6. 6. The method for preparing the iron-modified hydroxyl-rich metal organic framework material according to claim 3, wherein the method comprises the steps of, The metal organic framework NU-1000-OH is prepared by the following preparation method: And (3) reacting the structural ligand shown in the formula I with a zirconium ion precursor under a second solvothermal condition to prepare the metal organic framework NU-1000-OH.
  7. 7. The method for preparing the iron-modified hydroxyl-rich metal organic framework material according to claim 6, wherein the method comprises the steps of, The zirconium ion precursor is any one of hydrochloride, sulfate, nitrate, acetate or hydrate thereof of tetravalent zirconium ions; The ratio of the structural ligand shown in the formula I to the amount of the zirconium ion precursor is 1 (3-3.5).
  8. 8. The method for preparing the iron-modified hydroxyl-rich metal organic framework material according to claim 6, wherein the method comprises the steps of, The second solvent is N, N-dimethylformamide, and the mass volume ratio of the structural ligand shown in the formula I to the N, N-dimethylformamide is (4-10) mu mol to 1mL; the temperature of the solvothermal reaction is 100-140 ℃ and the reaction time is 24-96h.
  9. 9. The method for preparing the iron-modified hydroxyl-rich metal organic framework material according to claim 6, wherein the method comprises the steps of, The solvothermal reaction is carried out in the presence of benzoic acid, and the benzoic acid content is 50-100 times of the mass of the structural ligand shown in the formula I.
  10. 10. Use of the iron-modified hydroxyl-rich metal organic framework material according to claim 1 or 2, or the iron-modified hydroxyl-rich metal organic framework material according to any one of claims 3 to 9, in the preparation of ammonia by electrocatalytic nitrate reduction.

Description

Iron-modified hydroxyl-enriched metal organic framework material, preparation method thereof and application of iron-modified hydroxyl-enriched metal organic framework material in preparing ammonia through electrocatalytic nitrate reduction Technical Field The invention belongs to the technical field of metal organic frame functional materials, and particularly relates to an iron-modified hydroxyl-rich metal organic frame material, a preparation method thereof and application of electrocatalytic nitrate radical reduction to ammonia production. Background The electrocatalytic reduction of nitrate to ammonia is a promising alternative method, and can directionally reduce excessive nitrate in water to ammonia with high added value under the mild condition of normal temperature and normal pressure, thereby realizing the recycling utilization of changing waste into valuable, and cutting off the environmental risk path of converting nitrate into nitrite or greenhouse gas from the source. Although the electrocatalytic nitrate reduction ammonia production technology has certain advantages, the noble metal-based catalyst widely used at present is limited by the problems of high cost, scarce reserves, easy poisoning and deactivation and the like, and part of non-noble metal catalysts have the problems of insufficient activity, poor selectivity, poor stability and the like. Therefore, the development of a high-efficiency electrocatalyst which is non-noble metal, definite in structure, low in cost and simple and convenient to operate is a key rupture of the electrocatalytic nitrate reduction ammonia production. The metal organic framework material has the characteristics of high specific surface area, clear crystal structure, capability of accurately designing active sites on an atomic layer, rich metal centers, good dispersibility and the like, has great potential in the fields of energy storage, catalysis and the like, and provides an ideal platform for designing new-generation nitrate reduction electrocatalysts. Disclosure of Invention For the above reasons, a first object of the present invention is to provide an iron-modified hydroxyl-rich metal organic framework material, in which carboxyl groups on a pyrene compound ligand are coordinated with zirconium ions to form a metal organic framework, and substituted hydroxyl groups on the pyrene compound ligand can be further coordinated with inexpensive metal Fe as anchor groups, so that Fe ions are modified on the metal organic framework to form a second catalytic active center, and the modified metal organic framework is stable and has high catalytic performance. The second purpose of the invention is to provide a preparation method of the iron-modified hydroxyl-rich metal organic framework material, wherein carboxyl and hydroxyl substituted pyrene compounds are used as ligands, carboxyl and zirconium ions coordinate to form a metal organic framework in solvothermal reaction, and further, the iron is modified in the metal organic framework by chelation of hydroxyl and iron ions, so that the preparation method has mild reaction conditions and simple process, and is suitable for mass preparation. The third purpose of the invention is to provide an application of the iron modified hydroxyl-enriched metal organic framework material in electrocatalytic reduction of nitrate to ammonia, wherein Faraday efficiency reaches 90%, ammonia yield is high, and the catalyst has excellent cycle performance. The first object of the invention can be achieved by adopting the following technical scheme: an iron modified hydroxyl-rich metal organic framework material comprises a metal organic framework NU-1000-OH formed by coordination of carboxyl and Zr 4+ in a structural ligand shown in a formula I, and iron ions coordinated with hydroxyl on the structural ligand shown in the formula I in the NU-1000-OH; 。 Further, zr 4+ forms Zr 6 metal clusters, each Zr 6 metal cluster is coordinately connected with one carboxyl group in each ligand of eight structural ligands shown in formula I, two oxygen atoms of the carboxyl group in each structural ligand shown in formula I are coordinately connected with one axial zirconium and equatorial zirconium in the Zr 6 metal cluster respectively, each equatorial zirconium coordinately connected with two structural ligands shown in formula I, and each axial zirconium coordinately connected with four structural ligands shown in formula I. The second object of the invention can be achieved by adopting the following technical scheme: the preparation method of the iron modified hydroxyl-rich metal organic framework material comprises the following steps: and carrying out modification reaction on the metal organic frameworks NU-1000-OH and ferric ion salt in a first solvent to obtain the iron modified hydroxyl-rich metal organic framework material. Further, the ferric ion salt is any one of ferric hydrochloride, ferric sulfate, ferric nitrate, ferric acetate o