Preparation method and application of LaCoO3 nanomaterial with oxygen vacancies

A technology of nanomaterials and oxygen vacancies, applied in chemical instruments and methods, metal/metal oxide/metal hydroxide catalysts, chemical/physical processes, etc., can solve the problem of non-unique evaluation indicators of geometric area catalysts and low ammonia production rate etc. to achieve good catalytic stability, lower reaction energy barrier, and promote activity and selectivity

Active Publication Date: 2019-09-13
UNIV OF SCI & TECH OF CHINA
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  • Description
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Problems solved by technology

[0009] Most of the ammonia production rates of the above-mentioned catalysts reported are generally low, and the performance of individual catalysts is relatively high, but they have used different test conditions and evaluation methods, such as using different electrolytes (such as high-concentration potassium ion solutions as electrolytes) can inhibit the hydrogen production reaction), or the evaluation index of the catalyst is not unique due to factors such as the geometric area of ​​the electrocatalyst

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  • Preparation method and application of LaCoO3 nanomaterial with oxygen vacancies
  • Preparation method and application of LaCoO3 nanomaterial with oxygen vacancies
  • Preparation method and application of LaCoO3 nanomaterial with oxygen vacancies

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[0037] Specifically, the embodiment of the present invention discloses a kind of LaCoO with oxygen vacancies 3 Preparation methods of nanomaterials, including:

[0038]LaCoO 3 Nanomaterials etched in argon plasma to yield LaCoO with surface oxygen vacancies 3 nanomaterials.

[0039] This application is preparing LaCoO with surface oxygen vacancies 3 In the process of nanomaterials, LaCoO was realized by etching 3 The surface of nanomaterials has oxygen vacancies. LaCoO described in this application 3 Nanomaterials are prepared according to methods well known to those skilled in the art, for example, the LaCoO 3 The preparation method of nanomaterials is:

[0040] Mixing lanthanum source, cobalt source, urea, citric acid monohydrate, water and concentrated nitric acid to obtain a gel;

[0041] The gel is dried after heating, and finally calcined to obtain LaCoO 3 nanomaterials.

[0042] In the above LaCoO 3 In the preparation process of nanomaterials, the lanthanum s...

Embodiment 1

[0054] The present invention provides a LaCoO with surface oxygen vacancies 3 The nano catalyst has an average size of 60 nanometers to 100 nanometers, and its synthesis method is as follows:

[0055] Lanthanum nitrate hexahydrate, cobalt acetate tetrahydrate, urea and citric acid monohydrate were dissolved in 30mL of water, wherein the concentrations of lanthanum nitrate hexahydrate and cobalt acetate tetrahydrate were 0.125 mol / liter, and the concentrations of urea and citric acid monohydrate were both 0.125 mol / liter. 0.5 mol / L, add 3 ml of concentrated nitric acid, mix well, heat to 80°C, and magnetically stir until a gel is formed; then dry at 170°C for 12 hours, and the obtained sample is calcined at 600°C under oxygen for 6 hours to obtain LaCoO 3 nanocatalyst.

[0056] LaCoO 3 The nanocatalyst was placed in argon plasma, the power supply was 200 watts, the argon pressure was maintained at 10 torr, and the zinc oxide nanosheets were etched with argon plasma for 30 min...

Embodiment 2

[0059] 3 mg of LaCoO with surface oxygen vacancies 3 Nano-catalyst, 12 mg of activated carbon and 100 microliters of 5% Nafion solution were dispersed in 2.9 milliliters of ethanol, and ultrasonicated for 1 hour to obtain a uniform solution; then, 5 microliters of the above solution was evenly dropped on a 0.5 cm diameter rotating On the disk electrode, the rotating disk electrode is used as the working electrode, the silver / silver chloride electrode is used as the reference electrode, the graphite rod is used as the counter electrode, and 0.1 mol / liter potassium sulfate solution is used as the electrolyte with 30 milliliters of concentration. It is carried out in an H-type electrolytic cell. The electrolytic cell is separated by a Nafion 115 proton exchange membrane. Before the reaction, it is necessary to pass nitrogen gas for at least 30 minutes to drive away other gases. Nitrogen gas is continuously fed at a rate of 10 ml / min; during the reaction, the anode The generated o...

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Abstract

The invention provides a preparation method of a LaCoO3 nanomaterial with surface oxygen vacancies. The method is characterized in that a LaCoO3 nanomaterial is etched in argon plasma to obtain the LaCoO3 nanomaterial with surface oxygen vacancies. The invention also provides an application of the LaCoO3 nanomaterial with surface oxygen vacancies in a reaction for electrochemical reduction of nitrogen to synthesize ammonia. The oxygen vacancies are introduced to improve the performances of the metal oxide LaCoO3 nanomaterial, so the obtained LaCoO3 nanomaterial with oxygen vacancies has the advantages of high catalytic activity, high catalytic stability and high selectivity.

Description

technical field [0001] The invention relates to the technical field of catalysts, in particular to a LaCoO with oxygen vacancies 3 Preparation methods and applications of nanomaterials. Background technique [0002] Ammonia is a very important chemical raw material, which plays a very important role in industrial and agricultural production. At present, industrial ammonia synthesis through the Haber process requires high temperature and high pressure conditions (150-350 atmospheres, 350-550° C.), and such harsh conditions need to consume 1-2% of the world's energy supply every year. In addition, the traditional Haber method of ammonia synthesis requires hydrogen as one of the raw materials, and the traditional hydrogen production process will emit a large amount of CO 2 . Therefore, it is particularly important to explore the catalytic reaction for the synthesis of ammonia under mild conditions. [0003] The electrochemical reduction of nitrogen to synthesize ammonia can...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/83C25B1/00C25B11/06
CPCB01J23/83B01J35/0033C25B1/00C25B11/091
Inventor 刘彦李秋瑶孔祥栋耿志刚曾杰
Owner UNIV OF SCI & TECH OF CHINA
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