CN115385392A - Nano porous perovskite type oxide and preparation method and application thereof - Google Patents

Nano porous perovskite type oxide and preparation method and application thereof Download PDF

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CN115385392A
CN115385392A CN202210980188.5A CN202210980188A CN115385392A CN 115385392 A CN115385392 A CN 115385392A CN 202210980188 A CN202210980188 A CN 202210980188A CN 115385392 A CN115385392 A CN 115385392A
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alloy
perovskite
vacuum
type oxide
nanoporous
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司聪慧
张文超
马俊艺
尹慧丽
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Qilu University of Technology
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G51/00—Compounds of cobalt
    • C01G51/40—Cobaltates
    • C01G51/66—Cobaltates containing alkaline earth metals, e.g. SrCoO3
    • C01G51/68—Cobaltates containing alkaline earth metals, e.g. SrCoO3 containing rare earth, e.g. La0.3Sr0.7CoO3
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/40—Nickelates
    • C01G53/66—Nickelates containing alkaline earth metals, e.g. SrNiO3, SrNiO2
    • C01G53/68—Nickelates containing alkaline earth metals, e.g. SrNiO3, SrNiO2 containing rare earth, e.g. La1.62 Sr0.38NiO4
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/02—Hydrogen or oxygen
    • C25B1/04—Hydrogen or oxygen by electrolysis of water
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
    • C25B11/077—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound the compound being a non-noble metal oxide
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    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/16—Pore diameter

Abstract

The invention belongs to the technical field of nano porous materials, and particularly relates to a nano porous perovskite type oxide and a preparation method and application thereof. The perovskite type oxide comprises the following elements: la element, ca element, M element and O element; wherein, the M element is one or two of Co element and Ni element. On one hand, the material does not contain noble metal elements, so the material is relatively low in price and easy to obtain; meanwhile, co element and Ni element are selected to occupy the B site of the perovskite oxide, which is beneficial to promoting the electrochemical performance of the electrocatalytic material. The preparation method combines the alloy design, the dealloying method and the annealing process, and converts the block alloy into the nano porous perovskite type oxide with high specific surface area. The method is simple, can effectively prepare the perovskite type oxide, and has a nano porous structure and a large specific surface area.

Description

Nano-porous perovskite type oxide and preparation method and application thereof
Technical Field
The invention belongs to the technical field of nano porous materials, and particularly relates to a nano porous perovskite type oxide and a preparation method and application thereof.
Background
The implementation of new energy technologies, including electrocatalysis, solar cells, fuel cells, water splitting, metal-air batteries and the like, is of great importance to the sustainable development of the society, and has attracted extensive attention in recent years. In these techniques, since many reactions involve multistage electron transfer and proton coupling processes, the appropriate use of a catalyst is an effective way to reduce the reaction overpotential and improve the energy conversion efficiency. Currently, noble metal-based electrocatalysts (e.g., pt-based, pd-based, ir-based, etc.) generally exhibit high catalytic activity in these reactions, however, their scarcity and high cost limit their widespread use. To overcome this problem, perovskite-type oxides, which are abundant in raw materials, low in cost, various in kinds and excellent in electrocatalytic properties, are gradually becoming one of the alternative electrocatalytic materials.
The structural general formula of the perovskite type oxide is ABO 3 (wherein the ions at the A site are usually alkaline earth or rare earth metal ions, and the ions at the B site are usually transition metal ions), when the ions at the A, B are completely or partially substituted by metal ions with different ionic radii, valence states and electronegativity, lattice defects in the form of cation vacancies or oxygen anion vacancies are often induced, the crystal structure of the lattice defects is not significantly changed (the stability of the crystal structure), but the physicochemical properties are usually changed subtly. Moreover, due to the change of ion valence (abnormal valence and mixed valence) and the generation of crystal lattice defects in the form of vacancies, the electrical conductivity and the material transmission rate of the oxide are greatly improved, and stronger functionality, such as higher catalytic activity, stability and the like, is displayed.
Currently, there are a variety of methods for preparing perovskite materials. As disclosed in the prior art, a hydrothermal synthesis of Ba-doped Sr 2 Fe 1.5 Mo 0.5 O 6 The method of double perovskite nano material is that according to the stoichiometric number of Sr, ba, fe and Mo in perovskite material, the raw materials are added into water in turn,then adding complexing agent citric acid and dispersant polyethylene glycol to obtain precursor solution; then carrying out hydrothermal reaction on the precursor solution, centrifuging, cleaning and drying; and finally calcining in the atmosphere to obtain the nano material. The double perovskite anode material prepared by the method is used as a solid oxide fuel cell anode material and has good performance. As another example, the prior art also discloses a perovskite material CsPbX 3 The preparation method adopts a simple microwave heating synthesis process, firstly, a cesium precursor and a lead precursor are mixed in a microwave bottle at normal temperature, and then octadecene, a polar solvent and a surfactant are added to obtain a mixed solvent; ultrasonically dissolving the mixed solvent at normal temperature, heating and reacting in a microwave heating device, stopping microwave heating and cooling after reaction, and quickly cooling reaction liquid; finally, adding a cleaning agent into the reaction liquid after the rapid cooling, and centrifugally washing to obtain the solid CsPbX 3 A perovskite material. However, there is no report on the direct conversion of bulk alloys into nanoporous perovskite oxides by simple techniques and their application to the field of electrocatalysis.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a nano-porous perovskite oxide, a preparation method and application thereof, and the (La, ca) MO of the invention 3 The (M = Co, ni) perovskite bifunctional electrocatalytic material not only has excellent Oxygen Evolution Reaction (OER) electrocatalytic activity, but also has excellent Oxygen Reduction Reaction (ORR) performance and good stability.
In order to achieve the purpose, the invention adopts the following technical scheme:
a nanoporous perovskite-type oxide which is (La, ca) MO 3 (M = Co, ni); the micro-morphology is a nano-porous structure, and the aperture of the nano-porous is 1-100nm.
The invention also provides a preparation method of the nano porous perovskite type oxide. The preparation method realizes the conversion of the block alloy into the nano porous perovskite oxide with high specific surface area, has simple preparation method, easy realization of conditions and low cost, can be produced in large scale and has good application prospect.
A process for preparing the nano-porous perovskite oxide features that the alloy design, dealloying method and annealing process are combined together to transform the block alloy into the nano-porous perovskite oxide with high specific surface area.
The preparation method of the perovskite oxide comprises the following steps:
(1) In the aspect of alloy design, selecting original metal with the purity of more than 99.9 percent, and batching according to each atomic ratio; placing the prepared raw materials into a vacuum arc furnace for smelting to obtain uniform alloy ingots; and then preparing the alloy strip from the alloy cast ingot in a vacuum melt-spun machine.
(2) In the dealloying aspect, the alloy strip in the step (1) is placed in a corrosive solution with a certain concentration for chemical dealloying, and is cleaned to remove corrosion products and impurities, and the cleaned sample is dried in vacuum at a certain temperature.
(3) In the aspect of annealing treatment, the dealloyed sample obtained in the step (2) is placed in a muffle furnace, the temperature is raised at a certain heating rate, then annealing treatment is carried out at a certain temperature, after the temperature is kept for a plurality of hours, the furnace is cooled, and after the temperature is cooled to room temperature, the nano porous perovskite type oxide can be obtained.
According to the present invention, it is preferable that the original metal in the step (1) is Al element, la element, ca element, M element; preferably, the M element is one or both of a Co element and a Ni element.
According to the present invention, it is preferable that the atomic percentages in step (1) are Al element: 88%, la element: 3%, ca element: 3%, M element: 6 percent.
According to the present invention, it is preferable that the etching solution in the step (2) is a NaOH solution.
According to the present invention, it is preferable that the etching solution in the step (2) has a concentration of 2M.
According to the present invention, it is preferable that the vacuum drying temperature in the step (2) is 60 ℃.
According to the present invention, it is preferable that the temperature increase rate in the step (3) is 4 ℃/min.
According to the present invention, it is preferable that the annealing temperature in the step (3) is 800 ℃.
According to the invention, the annealing holding time in the step (3) is preferably 2h.
In an alternative embodiment, the operation steps of melting the raw materials in the vacuum arc furnace to obtain a uniform alloy ingot specifically include:
placing the prepared raw materials in a smelting pit of a vacuum arc furnace;
vacuumizing and filling high-purity argon;
repeatedly smelting under the protection of high-purity argon to obtain an alloy ingot.
In an optional embodiment, the operation steps of performing vacuum pumping treatment and filling high-purity argon gas include:
the vacuum degree of the equipment cavity reaches 3 multiplied by 10 through rough pumping of a mechanical pump and fine pumping of a molecular pump -3 After Pa, filling high-purity argon; vacuum pumping is carried out again until the vacuum pressure is 3 multiplied by 10 -3 And after Pa, high-purity argon is introduced again.
In an alternative embodiment, in the step of repeatedly smelting under the protection of high-purity argon for multiple times to obtain the alloy ingot:
the smelting times are 4-7 times.
In an optional embodiment, the operation step of preparing the alloy strip from the alloy ingot in the vacuum melt-spun machine specifically comprises the following steps:
crushing the alloy cast ingot, and placing a part of the crushed alloy cast ingot in a quartz tube of a vacuum melt-spun machine as a master alloy;
adjusting the vacuum degree of the furnace chamber of the vacuum melt-spun machine to 2 multiplied by 10 -3 After Pa, starting a stepless speed regulating motor, and switching on an induction coil power supply after the rotating speed of the copper roller reaches a preset rotating speed to completely melt the master alloy in the quartz tube to obtain an alloy melt;
and (3) instantly filling high-purity argon into the quartz tube to form a preset pressure difference between the quartz tube and a furnace chamber of the vacuum melt-spun machine, driving the alloy melt to be sprayed to the surface of the copper roller from a nozzle of the quartz tube under the action of the preset pressure difference, and rapidly cooling to form an alloy strip.
In an optional embodiment, the preset rotating speed of the copper roller is 2000-3500 rpm;
the preset pressure difference formed between the quartz tube and the furnace chamber is 0.03-0.05 MPa.
In an alternative embodiment, the operation of placing the alloy strip into a 2M NaOH solution to remove Al components and cleaning to remove impurities specifically comprises:
the alloy strip was placed in a 150mL beaker, then 2M NaOH solution was poured, and left for a period of time until no air bubbles appeared in the beaker, the supernatant was poured out and washed 5-6 times with water and ethanol, respectively, to remove impurities.
In an optional embodiment, the operation steps of drying the cleaned and dried sample in vacuum at 60 ℃ and then annealing to obtain the nanoporous perovskite oxide specifically include:
and (3) putting the cleaned and dried sample into a vacuum drying oven, setting the temperature to be 60 ℃, and pumping out air in the vacuum drying oven by using a vacuum pump, wherein the drying time is 11-12h. And (3) putting the dried product into a crucible, heating to 800 ℃ in a muffle furnace at a speed of 4 ℃/min, preserving heat for 2 hours, and then carrying out furnace cooling treatment to prepare the nano porous perovskite type oxide.
The invention also discloses application of the nano-porous perovskite oxide, and the perovskite oxide is used as an electrocatalytic material.
Advantageous effects
The perovskite type oxide comprises the following elements: la element, ca element, M element and O element; wherein, the M element is one or two of Co element and Ni element. On one hand, the material does not contain noble metal elements, so the material is relatively low in price and easy to obtain; meanwhile, co element and Ni element are selected to occupy B site of perovskite oxide, which is beneficial to promoting electrochemical performance of electrocatalytic material.
The preparation method combines the alloy design, dealloying method and annealing process, and converts the block alloy into the nano porous perovskite type oxide with high specific surface area. The method comprises the steps of obtaining alloy ingots with uniform components by adopting a non-consumable vacuum arc furnace, obtaining alloy strips after vacuum melt spinning, removing Al elements by an alloy removing technology, and then annealing to obtain the nano porous perovskite type oxide. The method is simple and can effectively prepare the perovskite type oxide, and the perovskite type oxide is of a nano porous structure and has a large specific surface area.
Description of the drawings:
FIG. 1 is an X-ray diffraction pattern of the dealloyed samples prepared in example 1 of the present invention and comparative examples 1 and 2.
FIG. 2 is an X-ray diffraction pattern of the perovskite-type oxide prepared in example 1 of the present invention and comparative examples 1 and 2.
FIG. 3 is a scanning electron micrograph a of the perovskite-type oxide electrocatalytic material prepared in example 1.
FIG. 4 is a scanning electron micrograph b of the perovskite-type oxide electrocatalytic material prepared in example 1.
FIG. 5 is a graph of the perovskite-type oxide electrocatalytic material prepared in example 1 and comparative examples 1 and 2 at O 2 ORR polarization plot at a scan rate of 10mV/s in a saturated 0.1M KOH solution.
FIG. 6 is a graph of the perovskite-type oxide electrocatalytic material prepared in example 1 and comparative examples 1 and 2 at O 2 OER polarization plot at a scan rate of 10mV/s in saturated 1M KOH solution.
Detailed Description
Hereinafter, the present invention will be described in detail. Before the description is made, it should be understood that the terms used in the present specification and the appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present invention on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation. Accordingly, the description proposed herein is just a preferable example for the purpose of illustrations only, not intended to limit the scope of the invention, so it should be understood that other equivalents and modifications could be made thereto without departing from the spirit and scope of the invention.
The following examples are given by way of illustration of embodiments of the invention and are not to be construed as limiting the invention, and it will be understood by those skilled in the art that modifications may be made without departing from the spirit and scope of the invention. Unless otherwise specified, reagents and equipment used in the following examples are commercially available products.
Description of terms:
unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
Example 1
This example provides a perovskite-type oxide La 0.5 Ca 0.5 Co 0.5 Ni 0.5 O 3 The preparation method comprises the following steps:
(1) The method comprises the following steps of mixing original metals Al, la, ca, co and Ni with the purity of more than 99.9% according to the atomic percentage of 88:3:3:3:3, preparing materials;
(2) Smelting the high-purity metal in a vacuum arc furnace, which specifically comprises the following steps:
placing the prepared raw materials in a smelting pit of a vacuum arc furnace;
the vacuum degree of the equipment cavity reaches 3 multiplied by 10 by rough pumping of a mechanical pump and fine pumping of a molecular pump -3 After Pa, filling high-purity argon; then, vacuum was again applied to 3X 10 -3 After Pa, high-purity argon is introduced again;
under the protection of high-purity argon, repeatedly smelting the alloy ingot for 4-7 times to obtain the alloy ingot with uniform components.
(3) The alloy ingot casting is flapped in a vacuum flail strip machine to obtain an alloy strip, and the method specifically comprises the following steps:
crushing the alloy cast ingot, and placing a part of the crushed alloy cast ingot as a master alloy in a quartz tube (the nozzle section is 0.2 multiplied by 3 mm) 2 ) The preparation method comprises the following steps of (1) performing;
when the vacuum degree of the furnace chamber of the vacuum melt-spun machine reaches 2 multiplied by 10 -3 After Pa, startA step of moving a stepless speed regulating motor, and switching on a power supply of an induction coil after the rotating speed of a copper roller reaches 3500rpm (the surface linear velocity is about 35 m/s) so as to completely melt a mother alloy rod in a quartz tube;
then high-purity argon is instantly filled into the quartz tube, a pressure difference (0.05 MPa) is built between the quartz tube and the furnace chamber, and alloy melt is driven to be directly sprayed onto a copper roller rotating at a high speed and is rapidly cooled to form a strip.
(4) The method comprises the following steps of performing dealloying and annealing treatment on an alloy strip to obtain a nano porous perovskite type oxide, and specifically comprises the following steps:
the alloy strip was placed in a 150mL beaker, then a sufficient amount of 2M NaOH solution was poured, allowed to stand at room temperature for a period of time, and when no bubbles appeared in the beaker, the supernatant was poured out and washed 5-6 times with water and absolute ethanol, respectively, to remove impurities.
And (3) putting the cleaned alloy into a vacuum drying oven, setting the temperature to be 60 ℃, and pumping out air in the vacuum drying oven by using a vacuum pump, wherein the drying time is 11-12h. And (3) placing the dried product in a crucible, placing the crucible in a muffle furnace, heating to 800 ℃ at a heating rate of 4 ℃/min, preserving heat for 2h, and then carrying out furnace cooling treatment to prepare the nano porous perovskite type oxide.
Through detection, the phase structure of the sample after the dealloying in this embodiment is shown in fig. 1, and the phase structure of the sample after the annealing in this embodiment is shown in fig. 2. As can be seen from the figure, the host phase after annealing has a perovskite structure. Scanning Electron Micrographs (SEM) of the perovskite oxide produced in this example are shown in fig. 3 and 4. As can be seen from FIGS. 3 and 4, the prepared sample has a nanoporous structure, and the pore diameter of the nanoporous structure is 1-100nm. The electrocatalytic performance of the perovskite-type oxide prepared in this example is shown in fig. 5 and 6, and it can be seen from fig. 5 and 6 that the perovskite-type oxide prepared in this example has excellent oxygen reduction (ORR) and Oxygen Evolution (OER) performance.
Comparative example 1
This example provides a perovskite-type oxide La 0.5 Ca 0.5 NiO 3 The preparation method comprises the following steps:
(1) The method comprises the following steps of mixing original metal Al, la, ca and Ni with the purity of more than 99.9% according to the atomic percentage of 88:3:3:6, preparing materials;
(2) Smelting the high-purity metal in a vacuum arc furnace;
wherein, the step (2) specifically comprises the following steps:
placing the prepared raw materials in a smelting pit of a vacuum arc furnace;
the vacuum degree of the equipment cavity reaches 3 multiplied by 10 through rough pumping of a mechanical pump and fine pumping of a molecular pump -3 After Pa, filling high-purity argon; then, vacuum was again applied to 3X 10 -3 After Pa, high-purity argon is introduced again;
under the protection of high-purity argon, repeatedly smelting the alloy ingot for 4-7 times to obtain the alloy ingot with uniform components.
(3) Carrying out melt spinning on the alloy cast ingot in a vacuum melt spinning machine to obtain an alloy strip;
wherein, the step (3) specifically comprises:
crushing the alloy cast ingot, and placing a part of the crushed alloy cast ingot as a master alloy in a quartz tube (the nozzle section is 0.2 multiplied by 3 mm) 2 ) Performing the following steps;
when the vacuum degree of the furnace chamber of the vacuum melt-spun machine reaches 2 multiplied by 10 -3 After Pa, starting a stepless speed regulating motor, and switching on an induction coil power supply after the rotating speed of the copper roller reaches 3500rpm (the surface linear velocity is about 35 m/s) so as to completely melt the mother alloy rod in the quartz tube;
then high-purity argon is instantaneously filled into the quartz tube, a pressure difference (0.05 MPa) is built between the quartz tube and the furnace chamber, the alloy melt is driven to be directly sprayed onto a copper roller rotating at a high speed, and the strip is rapidly cooled to form the strip.
(4) And performing dealloying and annealing treatment on the alloy strip to obtain the nano porous perovskite type oxide.
Wherein, the step (4) specifically comprises the following steps:
the alloy strip was placed in a 150mL beaker, then a sufficient amount of 2M NaOH solution was poured, allowed to stand at room temperature for a period of time, and when no bubbles appeared in the beaker, the supernatant was poured out and washed 5-6 times with water and absolute ethanol, respectively, to remove impurities.
And (3) putting the cleaned alloy into a vacuum drying oven, setting the temperature to be 60 ℃, and pumping out air in the vacuum drying oven by using a vacuum pump, wherein the drying time is 11-12h. And (3) placing the dried product in a crucible, placing the crucible in a muffle furnace, heating to 800 ℃ at a heating rate of 4 ℃/min, preserving heat for 2h, and then carrying out furnace cooling treatment to prepare the nano porous perovskite type oxide.
Through detection, the phase structure of the sample after dealloying in this embodiment is shown in fig. 1, and the phase structure of the sample after annealing in this embodiment is shown in fig. 2. As can be seen from the figure, the host phase after annealing has a perovskite structure.
Comparative example 2
This example provides a perovskite-type oxide La 0.5 Ca 0.5 CoO 3 The preparation method comprises the following steps:
(1) The method comprises the following steps of (1) mixing original metal Al, la, ca and Co with the purity of more than 99.9% according to the atomic percentage of 88:3:3:6, preparing materials;
(2) Smelting the high-purity metal in a vacuum arc furnace;
wherein, the step (2) specifically comprises the following steps:
placing the prepared raw materials in a smelting pit of a vacuum arc furnace;
the vacuum degree of the equipment cavity reaches 3 multiplied by 10 by rough pumping of a mechanical pump and fine pumping of a molecular pump -3 After Pa, filling high-purity argon; then, vacuum was again applied to 3X 10 -3 After Pa, high-purity argon is introduced again;
under the protection of high-purity argon, repeatedly smelting the alloy ingot for 4-7 times to obtain the alloy ingot with uniform components.
(3) Carrying out melt spinning on the alloy cast ingot in a vacuum melt spinning machine to obtain an alloy strip;
wherein, the step (3) specifically comprises the following steps:
crushing the alloy cast ingot, and placing a part of the crushed alloy cast ingot as a master alloy in a quartz tube (the nozzle section is 0.2 multiplied by 3 mm) 2 ) Performing the following steps;
dangzhen (Chinese character of 'Dangzhen')The vacuum degree of the furnace chamber of the air-throwing belt machine reaches 2 multiplied by 10 -3 After Pa, starting a stepless speed regulating motor, and switching on an induction coil power supply after the rotating speed of the copper roller reaches 3500rpm (the surface linear velocity is about 35 m/s) so as to completely melt the mother alloy rod in the quartz tube;
then high-purity argon is instantaneously filled into the quartz tube, a pressure difference (0.05 MPa) is built between the quartz tube and the furnace chamber, the alloy melt is driven to be directly sprayed onto a copper roller rotating at a high speed, and the strip is rapidly cooled to form the strip.
(4) And performing dealloying and annealing treatment on the alloy strip to obtain the nano porous perovskite type oxide.
Wherein, the step (4) specifically comprises the following steps:
the alloy strip was placed in a 150mL beaker, then a sufficient amount of 2M NaOH solution was poured, allowed to stand at room temperature for a period of time, and when no bubbles appeared in the beaker, the supernatant was poured out and washed 5-6 times with water and absolute ethanol, respectively, to remove impurities.
And (3) putting the cleaned alloy into a vacuum drying oven, setting the temperature to be 60 ℃, and pumping out air in the vacuum drying oven by using a vacuum pump, wherein the drying time is 11-12h. And (3) placing the dried product into a crucible, placing the crucible into a muffle furnace, heating to 800 ℃ at a heating rate of 4 ℃/min, preserving heat for 2 hours, and then carrying out furnace cooling treatment to prepare the nano porous perovskite type oxide.
Through detection, the phase structure of the sample after dealloying in this embodiment is shown in fig. 1, and the phase structure of the sample after annealing in this embodiment is shown in fig. 2. As can be seen from the figure, the host phase after annealing has a perovskite structure.
Application example 1
The ORR performance test method comprises the following steps: a three-electrode system is adopted, a glassy carbon electrode coated by a sample is taken as a working electrode, a platinum wire is taken as a counter electrode, and an Hg/HgO electrode is taken as a reference electrode, and the electrolyte is as follows: 0.1M KOH solution. Before testing, oxygen is introduced to saturate the electrolyte. The scanning speed was 10mV/s.
FIG. 5 shows perovskite electrocatalytic materials prepared in example 1 and comparative example 1,2 in O 2 Saturated 0.1M KOH solution, scanning speed 10MORR polarization plot of V/s.
As can be seen from FIG. 5, la prepared in example 1 0.5 Ca 0.5 Co 0.5 Ni 0.5 O 3 La prepared from electrocatalytic material in comparison with comparative examples 1 and 2 0.5 Ca 0.5 NiO 3 And La 0.5 Ca 0.5 CoO 3 The perovskite electrocatalytic material has larger ORR limiting current density which can reach 6mA cm -2 Indicating better electrocatalytic performance for oxygen reduction.
Application example 2
The LSV test method for the performance of the OER comprises the following steps: a three-electrode system is adopted, a glassy carbon electrode coated by a sample is taken as a working electrode, a platinum wire is taken as a counter electrode, and an Hg/HgO electrode is taken as a reference electrode, and the electrolyte is as follows: 1M KOH solution. Before testing, oxygen is introduced to saturate the electrolyte. The scan speed was 10mV/s.
FIG. 6 shows perovskite electrocatalytic materials prepared in example 1 and comparative example 1,2 in O 2 OER polarization plot in saturated 1M KOH solution at a scan rate of 10mV/s.
As can be seen from FIG. 6, la prepared in example 1 0.5 Ca 0.5 Co 0.5 Ni 0.5 O 3 La prepared by comparing electrocatalytic material with comparative examples 1 and 2 0.5 Ca 0.5 NiO 3 And La 0.5 Ca 0.5 CoO 3 The perovskite electrocatalytic material has smaller overpotential and the current density is 10mA/cm 2 The overpotential is only 330mV.
The above examples are only intended to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof; such modifications and substitutions do not depart from the spirit and scope of the corresponding claims.

Claims (10)

1. A nano-porous perovskite oxide is characterized in thatThe structural general formula of the perovskite type oxide is (La, ca) MO 3 M is one or two of Co element and Ni element; the micro-morphology of the perovskite type oxide is a nano porous structure.
2. The nanoporous perovskite oxide according to claim 1, wherein the pores of the nanoporous perovskite oxide are between 1 and 100nm in diameter.
3. The nanoporous perovskite oxide according to claim 1, wherein the preparation method comprises the steps of:
(1) Alloy design: selecting original metals, and batching according to each atomic ratio; smelting the prepared raw materials to obtain uniform and consistent alloy ingots; then processing the alloy ingot to obtain an alloy strip;
(2) Dealloying: putting the alloy strip obtained in the step (1) into a corrosive solution with a certain concentration for chemical dealloying, then cleaning to remove corrosion products and impurities, and carrying out vacuum drying on the cleaned sample at a certain temperature to obtain a dealloyed sample;
(3) Annealing treatment: and (3) annealing the dealloying sample obtained in the step (2) at a certain temperature, keeping the temperature for a plurality of hours, cooling the furnace, and cooling to room temperature to obtain the nano porous perovskite type oxide.
4. The nanoporous perovskite-type oxide according to claim 3, wherein in step (1), the purity of the selected original metal is more than 99.9%, and the original metal is Al element, la element, ca element, M element; the M element is one or two of Co element and Ni element; the atomic percentage is Al element: 88% of La element: 3%, ca element: 3%, M element: 6 percent.
5. The nanoporous perovskite oxide according to claim 3, wherein in step (1), the smelting operation comprises in particular:
placing the prepared raw materials in a smelting pit of a vacuum arc furnace;
carrying out vacuum-pumping treatment, and filling high-purity argon: the vacuum degree of the equipment cavity reaches 3 multiplied by 10 by rough pumping of a mechanical pump and fine pumping of a molecular pump -3 After Pa, filling high-purity argon; vacuum pumping is carried out again until the vacuum pressure is 3 multiplied by 10 -3 After Pa, high-purity argon is filled again;
repeatedly smelting for many times under the protection of high-purity argon to obtain alloy ingots, wherein the smelting times are 4-7 times.
6. The nanoporous perovskite-type oxide according to claim 3, wherein in step (1), the step of processing the alloy ingot to obtain the alloy strip specifically comprises:
crushing the alloy cast ingot, and placing a part of the crushed alloy cast ingot in a quartz tube of a vacuum melt-spun machine as a master alloy;
adjusting the vacuum degree of the furnace chamber of the vacuum melt-spun machine to 2 multiplied by 10 -3 After Pa, starting a stepless speed regulating motor, and switching on a power supply of an induction coil after the rotating speed of the copper roller reaches a preset rotating speed so as to completely melt the master alloy in the quartz tube to obtain an alloy melt; the preset pressure difference formed between the quartz tube and the furnace chamber is 0.03-0.05 MPa;
filling high-purity argon into the quartz tube instantly to form a preset pressure difference between the quartz tube and a furnace chamber of the vacuum melt-throwing belt machine, driving the alloy melt to be sprayed to the surface of the copper roller from a nozzle of the quartz tube under the action of the preset pressure difference, and rapidly cooling to form an alloy strip; the preset rotating speed of the copper roller is 2000-3500 rpm.
7. The nanoporous perovskite-type oxide according to claim 3, wherein in step (2), the etching solution is NaOH solution and the etching solution has a concentration of 2M.
8. The nanoporous perovskite oxide according to claim 7, wherein the step (2) of dealloying specifically comprises:
putting the alloy strip into a container, then pouring 2M NaOH solution, standing for a period of time until no bubbles appear in the container, pouring out supernatant, and respectively cleaning the alloy strip with water and ethanol for 5-6 times to remove impurities;
and (3) putting the cleaned and dried alloy strip into a vacuum drying oven, setting the temperature to be 60 ℃, and pumping out air in the vacuum drying oven by using a vacuum pump, wherein the drying time is 11-12h.
9. The nanoporous perovskite oxide according to claim 3, wherein the annealing treatment of step (3) comprises in particular the following operating steps: and (3) putting the dealloyed sample obtained in the step (2) into a crucible, heating to 800 ℃ at a speed of 4 ℃/min in a muffle furnace, preserving heat for 2 hours, and then carrying out furnace cooling treatment to prepare the nano porous perovskite type oxide.
10. Use of a nanoporous perovskite oxide as defined in any one of claims 1 to 9 as electrocatalytic material.
CN202210980188.5A 2022-08-16 2022-08-16 Nano porous perovskite type oxide and preparation method and application thereof Pending CN115385392A (en)

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CN110013861A (en) * 2019-04-28 2019-07-16 五邑大学 A kind of Ag-LaCoO3-δNano combined electrocatalysis material and preparation method thereof

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CN104591302A (en) * 2015-01-05 2015-05-06 华北水利水电大学 Perovskite-type nanometer material and preparation method thereof
CN110013861A (en) * 2019-04-28 2019-07-16 五邑大学 A kind of Ag-LaCoO3-δNano combined electrocatalysis material and preparation method thereof

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