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CN-122010061-A - Polyoxometallate material with high proton conductivity and pure inorganic three-dimensional framework structure, and preparation method and application thereof

CN122010061ACN 122010061 ACN122010061 ACN 122010061ACN-122010061-A

Abstract

The method adopts a one-pot synthesis strategy, successfully synthesizes one example of polyoxometallate with high proton conductivity and a pure inorganic three-dimensional framework structure by precisely controlling the reaction temperature, the pH value and the proportion of each raw material, further carries out systematic test on the proton conductivity under different temperature and humidity conditions based on the structural characteristics of the polyoxometallate, then calculates the activation energy of proton migration of the polyoxometallate by carrying out Arrhenius fitting on experimental data, thereby deeply discussing the proton conduction mechanism of the polyoxometallate, and the polyoxometallate prepared by the method is a pure inorganic three-dimensional framework structure and is completely composed of metal-oxygen bonds, has important structural innovation significance, and in addition, the polyoxometallate has the advantages of high proton conductivity, simple preparation process, good chemical stability and the like, so that the polyoxometallate becomes a solid proton conduction material with extremely high application potential.

Inventors

  • SUN LIN
  • ZHANG HAIBO
  • GUO MENGKE

Assignees

  • 河南大学

Dates

Publication Date
20260512
Application Date
20260119

Claims (9)

  1. 1.A polyoxometallate material with high proton conductivity and pure inorganic three-dimensional framework structure is characterized in that the polyoxometallate material with a chemical formula ：[H 2 N(CH 3 ) 2 ] 8 K 3 Na 2 H 4 [Se 4 W 35 Ce 2 O 124 (H 2 O) 4 ]Cl·22H 2 O, belongs to a triclinic system, P-1 space group and unit cell parameters are as follows ：a = 19.5903(12) Å,b = 20.2582(12) Å,c = 25.1571(16) Å,α = 94.171(2) °,β = 96.315(2)°,γ = 117.546(2) °.
  2. 2. The method for preparing a polyoxometalate material having high proton conductivity and a pure inorganic three-dimensional framework structure according to claim 1, comprising the steps of: 1) Dissolving Na 2 WO 4 ·2H 2 O、[H 2 N(CH 3 ) 2 . Cl, KCl, naAc and Na 2 SeO 3 in deionized water to form colorless transparent solution; 2) Under continuous stirring, adjusting the pH of the solution to 4.0-4.5; 3) Adding Ce (NO 3 ) 3 ·6H 2 O into the solution and dissolving completely under stirring, wherein the solution turns yellow transparent, and then adjusting the pH of the solution to 4.0-4.5; 4) Heating at 70-90deg.C for 1-3 hr, cooling to room temperature, and separating solid from liquid to obtain clear yellow solution; 5) And standing at room temperature to naturally volatilize the solution, and separating out orange crystals to obtain the product.
  3. 3. The method for preparing a polyoxometalate material having high proton conductivity and a pure inorganic three-dimensional framework structure according to claim 1, wherein 1-3g Na 2 WO 4 ·2H 2 O、1-2g [H 2 N(CH 3 ) 2 ]·Cl、0.1-0.4g KCl、0.1-0.3g NaAc and 0.1-0.4g Na 2 SeO 3 are dissolved in 15-30 mL deionized water in step 1).
  4. 4. The method for preparing a polyoxometalate material having high proton conductivity and a pure inorganic three-dimensional framework structure according to claim 1, wherein in step 2), the pH is adjusted to 4.0 to 4.5 using 4 to 8 mol/L HCl.
  5. 5. The method for preparing polyoxometalate material having high proton conductivity and pure inorganic three-dimensional framework structure according to claim 3, wherein 0.1-0.3g Ce (NO 3 ) 3 ·6H 2 O) is added to the solution and dissolved completely in step 3).
  6. 6. The method for preparing a polyoxometalate material having high proton conductivity and a pure inorganic three-dimensional framework structure according to claim 3, wherein in step 3), the pH of the solution is adjusted to 4.0 to 4.5 using 4 to 8 mol/L HCl.
  7. 7. The polyoxometalate material with high proton conductivity and pure inorganic three-dimensional framework structure prepared by the method of any one of claims 2 to 6.
  8. 8. Use of the polyoxometalate material of claim 1 or 7 having high proton conductivity and a pure inorganic three-dimensional framework structure for the preparation of proton exchange membrane fuel cells.
  9. 9. Use of the polyoxometalate material having high proton conductivity and a pure inorganic three-dimensional framework structure according to claim 1 or 7 as a solid proton conducting material, a sensor, or an electrochemical device.

Description

Polyoxometallate material with high proton conductivity and pure inorganic three-dimensional framework structure, and preparation method and application thereof Technical Field Aiming at the urgent demands of the increasing exhaustion of traditional fossil energy and environmental management, the invention develops a polyoxometallate material with high proton conductivity and pure inorganic three-dimensional framework structure, and a preparation method and application thereof. The material utilizes rare earth ions as a connecting unit to construct a trimer selenium tungsten oxygen cluster, and further utilizes alkali metal ions as a bridging unit to expand the trimer structure into a stable three-dimensional framework structure. The invention not only optimizes the structural design of the polyacid semiconductor material, but also carries out intensive study on proton conductivity. The test result shows that the material has obvious proton conductivity response under different temperature and humidity conditions and excellent proton conductivity under high-temperature and high-humidity environments. In addition, the material has the advantages of simple and convenient preparation process, no toxicity and environmental protection, good chemical stability and application prospect, and provides scientific basis and technical support for the development of the high-efficiency solid proton conducting material in the future. Background In recent years, as fossil fuel reserves have been increasingly reduced, global interest and demand for renewable energy has continued to increase. In this context, proton Exchange Membrane Fuel Cells (PEMFCs) have been one of the most attractive clean energy technologies because of their rapid start-up and high power density. However, the proton conduction efficiency of the Nafion membrane, a key component of the PEMFC, is significantly reduced in a low-humidity and high-temperature environment, severely limiting its practical application and popularization. Therefore, the development of a novel material which can still maintain high-efficiency proton conductivity under severe conditions becomes a key research direction for improving the performance of PEMFCs and promoting the commercialization process of PEMFCs. Polyoxometalates (POMs) are a class of metal oxide clusters composed of high-valence transition metals (e.g., W, mo, V) that have been attracting attention in recent years due to their excellent proton conductivity, excellent thermal stability, and multifunctional chemical properties. POM can be classified into various types according to the framework structure thereof, including Silverton type [ XM 12O42]n-, wells-Dawson type [ XM 18O62]n-, keggin type [ XM 12O40]n-, LINDQVIST type [ M 6O19]n- ], preyssler type [ X n+P5W30O110](15-n)-, and Anderson-Evans type [ XM 6O24]n- ]. Among them, keggin-type and Dawson-type POMs have been widely studied and intensively studied in various fields such as catalysis, energy storage and proton conduction due to their relatively simple synthesis conditions, stable structure and excellent physicochemical properties. Particularly in the development of proton conducting materials, the two POMs are considered as potential candidate materials by virtue of unique adjustable structures, high-efficiency proton transmission capacity and excellent thermal stability, and are expected to play an important role in the future high-performance proton exchange membrane fuel cells and related technical fields. The advantages of POM in the proton conducting field are mainly due to its unique structural and chemical properties. First, the POM surface has a high density of oxygen atoms that provide a rich jump point for protons, thereby promoting proton conduction in the material. The migration of protons is not only dependent on the overall structure of the material, but is also affected by the surface microstructure. The surface of POM has nanoscale anionic clusters that exhibit lower charge density due to delocalization of the negative charge, providing favorable conditions for dynamic dissociation and migration of protons. In addition, POM is used as an acid-form material, the structure of the POM is composed of a polyoxoanion and a counter cation, and oxygen atoms in the polyoxoanion have strong electron withdrawing capability, so that protons can be quickly exchanged and transported between the oxygen atoms and hydrogen. This property makes POM exhibit excellent stability and high efficiency in proton conductivity, and especially under high humidity and high temperature conditions, POM can maintain good proton conductivity. Furthermore, the structure of the POM can be optimized by adjusting the metal center, the oxygen atom arrangement and the form of the anion clusters so as to meet the requirements of different application occasions. This structural adjustability allows the POM to provide customized proton conductivity properties according to diff