Silver-doped metal oxide and preparation method and application thereof
The preparation of silver-doped metal oxides by spinning method solves the problems of cumbersome preparation process and silver ion reduction in the prior art, and achieves a more efficient preparation process and a larger reactive site. It is suitable for zinc-air fuel cells.
Patent Information
- Application Number
- CN202411677590.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-22
- Publication Date
- 2025-03-18
AI Technical Summary
In the prior art, the preparation of the cathode material Sr0.95Ag0.05Nb0.1Co0.9O3-δ for perovskite structure requires multiple calcination at high temperature, the steps are complicated, and silver ions are easily reduced during the synthesis process, which affects the preparation efficiency.
The silver-doped metal oxide was prepared by spinning method. By controlling the spinning paste and process design, silver ion reduction was avoided, and the calcination temperature and number of times were reduced, and the nano-scale fiber-like Sr0.95Ag0.05Nb0.1Co0.9O3-δ was prepared.
It shortens the preparation time, provides more reactive sites, improves reactive activity, and is suitable for zinc-air fuel cells.
Smart Images
Figure CN119637947A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of electrochemistry, and in particular relates to a silver-doped metal oxide and a preparation method and application thereof. Background Art
[0002] Solid oxide fuel cells are an energy conversion technology that is efficient, clean, and environmentally friendly and can directly convert the chemical energy in fossil fuels such as coal, oil, and natural gas, biomass fuels such as biogas, and other hydrocarbons into electrical energy. 0.95 Ag 0.05 Nb 0.1 Co 0.9 O 3-δ It is a cathode material with a perovskite structure, mainly used in solid oxide fuel cells. The oxide has excellent electrochemical properties and stability due to its unique structure. 0.95 Ag 0.05 Nb 0.1 Co 0.9 O 3-δ The preparation of is mainly based on the ball milling method, which requires multiple calcinations at a relatively high calcination temperature (generally above 1100°C) and has complicated steps. Summary of the invention
[0003] In view of the above problems existing in the prior art, the present invention provides a silver-doped metal oxide and a preparation method and application thereof, which can shorten the preparation time of the silver-doped metal oxide and provide more reactive sites.
[0004] To achieve the above object, the technical solution provided by the present invention is as follows:
[0005] In a first aspect, the present application provides a method for preparing a silver-doped metal oxide, comprising the following steps:
[0006] S1: adding niobium oxalate to a solvent and stirring until dissolved, then sequentially adding silver nitrate, strontium nitrate, and cobalt nitrate hexahydrate and stirring to mix to obtain a premixed solution;
[0007] S2: Add polyacrylonitrile to the premixed solution and stir at 35-55°C for 10-15h to obtain a gel solution;
[0008] S3: The gel solution is spun to obtain a non-woven fabric, and the non-woven fabric is sintered at 900-1000° C. for 7-8 hours to obtain the silver-doped metal oxide, wherein the silver-doped metal oxide is Sr 0.95 Ag 0.05 Nb 0.1 Co 0.9 O 3-δ .
[0009] Optionally, in S1, niobium oxalate is first dissolved at 70-80° C., then the temperature is lowered to room temperature and silver nitrate is added. After the silver nitrate is added, the mixture is stirred for 20-30 minutes and then strontium nitrate is added.
[0010] Optionally, after polyacrylonitrile is added to the premixed solution, the reaction is stirred under sealed conditions or a nitrogen atmosphere.
[0011] Optionally, the spinning in S3 is performed at a voltage of 15 KV.
[0012] Optionally, in S3, the temperature is gradually increased to the desired calcination temperature at a rate of 2-4°C / min.
[0013] Optionally, the concentration of silver nitrate in the premix is 6-15 mol / L.
[0014] Optionally, the dosage ratio of the premixed liquid to polyacrylonitrile is (0.5-5):1 mmol / g in terms of silver:polyacrylonitrile.
[0015] Optionally, the degree of polymerization of polyacrylonitrile is 120,000-160,000.
[0016] Optionally, the amount ratio of the silver nitrate, strontium nitrate, niobium oxalate and cobalt nitrate hexahydrate in S1 is 0.05:0.95:0.1:0.9 in terms of silver:strontium:niobium:cobalt.
[0017] In a second aspect, the present application further provides a silver-doped metal oxide prepared according to the preparation method of the silver-doped metal oxide described in the first aspect.
[0018] In a third aspect, the present application also provides the use of the silver-doped metal oxide described in the second aspect in a zinc-air fuel cell.
[0019] Compared with the prior art, this application has at least the following beneficial effects:
[0020] The present invention innovatively prepares silver-doped metal oxide Sr by spinning method 0.95 Ag 0.05 Nb 0.1 Co 0.9 O 3-δ Through the control of spinning slurry and the design of process, the slurry coagulation caused by the reduction of silver ions during the synthesis process was avoided, and the calcination temperature and calcination times required for the synthesis were reduced. The prepared nano-fibrous Sr 0.95 Ag 0.05 Nb 0.1 Co 0.9 O 3-δ With a larger specific surface area, it can provide more reactive sites and improve the reaction activity when used as a zinc-air fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 X-ray diffraction patterns of the silver-doped metal oxides obtained in Example 1 and Comparative Example 1;
[0022] Figure 2 This is a scanning electron microscope image of the silver-doped metal oxide obtained in Example 1. DETAILED DESCRIPTION
[0023] The present invention is further described in detail below in conjunction with the accompanying drawings:
[0024] The experimental methods used in the embodiments of the present invention are conventional methods unless otherwise specified.
[0025] The reagents and materials used in this example can all be purchased conventionally. The quantitative experiments involved in the examples were repeated at least three times, and the results were averaged.
[0026] Source of raw materials:
[0027] Polyacrylonitrile: any polyacrylonitrile with a degree of polymerization of 120,000-160,000 is acceptable, and in this embodiment, the degree of polymerization is 150,000.
[0028] Example 1
[0029] Weigh 2mmol of silver nitrate, and weigh strontium nitrate, niobium oxalate, and cobalt nitrate hexahydrate according to the molar ratio of silver: strontium: niobium: cobalt of 0.05:0.95:0.1:0.9, add analytically pure niobium oxalate into N,N-dimethylformamide solvent at 80°C and stir until dissolved, then add silver nitrate thereto after cooling to room temperature, wherein the concentration of silver nitrate is 10mol / L, and stir for 30 minutes; then add strontium nitrate and stir to dissolve, and then add cobalt nitrate hexahydrate to obtain a premix after dissolution; add 1g of polyvinyl nitrile to the premix, and stir continuously for 15 hours at 40°C in a closed environment to obtain a gel solution; add the gel solution into a syringe, and spin it in a 15kV electrospinning machine, and the propulsion speed can be 0.8-1 mL / h, in this embodiment, the advancing speed is 1mL / h, and a non-woven fabric is obtained. The obtained non-woven fabric is placed in a crucible and heated to 1000°C at a speed of 2°C / min, and calcined at 1000°C for 10 hours to obtain silver-doped metal oxide Sr 0.95 Ag 0.05 Nb 0.1 Co 0.9 O 3-δ .
[0030] In this application, the order of adding reactants and the stirring temperature have a great influence. Niobium oxalate must be added first and dissolved at a relatively high temperature to obtain a transparent solution, and then silver nitrate is added after cooling to room temperature. When adding silver nitrate, if the temperature is too high, the solution will oxidize and turn black to form a precipitate. After adding silver nitrate, stir for 20-30 minutes to form a stable complex between silver nitrate and niobium oxalate, and then add strontium nitrate and cobalt nitrate in sequence to ensure that the several reactants in the mixed system are dissolved.
[0031] After adding polyacrylonitrile to the premix, the sealing and appropriate heating temperature must be controlled at the same time, otherwise insoluble precipitates or solid colloidal substances will be generated and spinning cannot be carried out.
[0032] Comparative Example 1
[0033] At room temperature, 2 mmol of silver nitrate was weighed, and strontium carbonate, niobium pentoxide, and cobalt trioxide were weighed according to the molar ratio of silver: strontium: niobium: cobalt of 0.05:0.95:0.1:0.9. Silver nitrate, strontium carbonate, niobium pentoxide, and cobalt trioxide were added to a ball mill, and 200 ml of acetone was used as a solvent medium. The ball mill was set to 400 rpm and ground for one hour; the ground material was placed in an oven at 60° C. and dried for one hour. The dried mixed powder was then placed in a muffle furnace and calcined at 1150° C. for 10 hours, and the process was repeated 3 times (repeated until a pure phase was obtained, generally at least 3 times were required) to obtain silver-doped metal oxide Sr 0.95 Ag 0.05 Nb 0.1 Co 0.9 O 3-δ .
[0034] The silver-doped metal oxides prepared in Example 1 and Comparative Example 1 were subjected to XRD and SEM tests. The test results are shown in Figure 1 and Figure 2 From the XRD results, it can be seen that the peak positions of the silver-doped metal oxide prepared by the method of the present application and the silver-doped metal oxide obtained by the traditional ball milling method are completely consistent, indicating that the method of the present application successfully prepared the silver-doped metal oxide. Figure 2 It can be seen from the SEM results that the present application successfully prepared nanoscale fibrous silver-doped metal oxides, which can provide more reaction active sites for use in zinc-air fuel cells.
[0035] Through experiments, it was found that when the non-woven fabric was calcined to prepare silver-doped metal oxide in the present application, the silver-doped metal oxide in the present application could not be obtained when the calcination temperature was lower than 900°C, and when the temperature was too high, the fibrous structure of the silver-doped metal oxide collapsed, causing the reaction active sites to decrease.
[0036] The above are only preferred embodiments of the present invention, and the present invention is not limited to the contents of the embodiments. For those skilled in the art, various changes and modifications can be made within the scope of the technical solution of the present invention, and any changes and modifications made are within the protection scope of the present invention.
Claims
1. A method for preparing silver-doped metal oxide, characterized in that: The steps include: S1: adding niobium oxalate to a solvent and stirring until dissolved, then adding silver nitrate, strontium nitrate and cobalt nitrate hexahydrate in sequence and stirring to mix to obtain a premixed solution; S2: Add polyacrylonitrile to the premixed solution and stir at 35-55°C for 10-15h to obtain a gel solution; S3: The gel solution is spun to obtain a non-woven fabric, and the non-woven fabric is sintered at 900-1000° C. for 7-8 hours to obtain the silver-doped metal oxide, wherein the silver-doped metal oxide is Sr 0.95 Ag 0.05 Nb 0.1 Co 0.9 O 3-δ .
2. The method for preparing silver-doped metal oxide according to claim 1, characterized in that: S1 first dissolves niobium oxalate at 70-80°C, then cools to 10-30°C and adds silver nitrate. After adding the silver nitrate, stir for 20-30 minutes and then add strontium nitrate.
3. The method for preparing silver-doped metal oxide according to claim 1, characterized in that: Spinning in S3 was carried out at a voltage of 15 KV.
4. The method for preparing silver-doped metal oxide according to claim 1, characterized in that: In S3, the temperature is gradually increased at a rate of 2-4°C / min to the desired calcination temperature.
5. The method for preparing silver-doped metal oxide according to claim 1, characterized in that: The concentration of silver nitrate in the premix is 6-15 mol / L.
6. The method for preparing silver-doped metal oxide according to claim 1, characterized in that: The dosage ratio of the premixed liquid to polyacrylonitrile is (0.5-5):1 mmol / g in terms of silver:polyacrylonitrile.
7. The method for preparing silver-doped metal oxide according to claim 1, characterized in that: The degree of polymerization of polyacrylonitrile is 120,000-160,000.
8. The method for preparing silver-doped metal oxide according to claim 1, characterized in that: The amount ratio of the silver nitrate, strontium nitrate, niobium oxalate and cobalt nitrate hexahydrate in S1 is 0.05:0.95:0.1:0.9 in terms of silver:strontium:niobium:cobalt.
9. A silver-doped metal oxide, characterized in that: Prepared according to the method for preparing silver-doped metal oxide according to any one of claims 1 to 9.
10. Use of the silver-doped metal oxide as claimed in claim 9 in a zinc-air fuel cell.