A method for preparing multilayer core-shell structure transition metal oxides in one step

Abstract

The invention relates to a method for preparing multilayer core-shell structure transition metal oxide at one step. The method comprises the following steps: dissolving a transition metal salt with a solvent, and then adding an organic additive to obtain a precursor solution; atomizing the precursor solution with an atomizer, and feeding the precursor solution into a vertical tube furnace with carrier gas for pyrolysis to obtain the multilayer core-shell structure transition metal oxide material. By adopting the method, the synthesized transition metal oxide is uniform in components, and is controllable in appearance and shell quantity; a high-purity and high-crystallinity multilayer core-shell structure transition metal oxide can be prepared without any separate subsequent burning process. Compared with the conventional method, the method has the advantages of easiness in operation, short flow, high efficiency, high suitability and the like.

Description

technical field [0001] The invention relates to the field of preparing metal oxide powder materials by a spray pyrolysis method, in particular to a method for preparing a transition metal oxide with a multilayer core-shell structure in one step. Background technique [0002] Transition metal oxides are widely used in electrode materials, catalysts, capacitor materials and other fields. With the continuous expansion of the application range, the requirements for the performance of the material itself are also getting higher and higher. Therefore, it is necessary to strictly control the preparation stage of powder materials. How to prepare transition metal oxide materials with uniform composition, regular shape and excellent performance has become a hot spot of concern. The spray pyrolysis method is widely used in the preparation of various metal oxide powder materials due to its simple process, high production efficiency, uniform components and high purity of the prepared pr...

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Problems solved by technology

[0003] At present, in order to prepare transition metal oxides with multilayer core-shell structure, most of them adopt complex and tedious multi-step synthesis methods, such as spray drying method, co-precipitation method, hydrothermal method, template method, etc., such as Guan Jianguo, etc. (Chinese Patent CN101898749A) Using composite ions containing metal compounds and polymers, through electrostatic spray pyrolysis to obtain single-layer hollow, core-shell structure, multi-layer hollow or multi-layer core-shell hollow metal oxide hollow particles or metal oxide hollow Fiber, but this method requires high equipment and complicated process; Nie Zuoren et al. (Chinese patent CN101475223A) prepared a solution by dissolving ferrous iron salt in distilled water, adding ammonium hydrofluoride, adding template agent, and roasting at 500-700°C to obtain The hollow microspheres of ferric oxide with a core-shell structure, the method steps are complicated, and various additives need to be added, and the obtained product has more impurities; Young JunHong et al. (“One-pot synthesis of core–shell-structured tin oxide–carbon compositepowders by spray pyrolysis for use as anode materials in Li-ion batteries", Young Jun Hong et al., "Carbon", volume 88, pages 262-269) mix stannous oxalate and PVP to prepare a solution, and use nitrogen as Carrier gas, one-step spray pyrolysis to prepare a composite material of core-shell structure tin dioxide and carbon, and discloses the direct use of low-concentration tin salt solution as a raw material to prepare tin dioxide powder. Although this method is simple, the nitrogen atmosphere Medium-PVP high-temperature carbonization, carbon is retained in the product and cannot form pure core-shell structure tin dioxide, and cannot obtain multi-level core-shell structure tin dioxide, and only use low-concentration tin oxalate solution as raw material, let alone form Core-shell structure; Jong Min Won (“Electrochemical properties of yolk-shell structured ZnFe 2 o 4 powders prepared by a simple spray drying process as anode material forlithium-ion battery", Jong Min Won et al., "SCIENTIFIC REPORTS", volume 4, pages 1-5) discloses that zinc nitrate and ferric nitrate are formulated into an aqueous solution , add dextrin, pump the solution into the atomization equipment, dry in the spray dryer, and then further calcined to obtain the core-shell structure of ZnFe 2 o 4 , this method requires further calcination after spray pyrolysis, and the number of shell layers cannot be controlled; Young Jun Hong et al. (“Superior electrochemical performances of double-shelled CuO yolk–shell powders formed from spherical coppernitrate-polyvinylpyrrolidone composite powders”, et al. "RSCAdvances", volume 4, pages 58231-58237) adopt copper nitrate and PVP dissolved in distilled water to obtain a spray precursor solution, and then spray and pyrolyze at 300°C to obtain a precursor solution, and further after 200-300°C The CuO powder with a double-layer core-shell structure was obtained by processing. Although this method can obtain CuO with a multi-layer core-shell structure, it still needs further calcination after fog pyrolysis, and the number of shell layers cannot be controlled; Seung Ho Choi et al. (“One-pot rapid synthesis of core–shellstructured NiO@TiO 2 nanopowders and their excellent electrochemical properties as anode materials for electrochemical properties as anode materials forlithium ion batteries", Seung Ho Choi et al., "Nanoscale", volume 5, pages 12645-12650) using nickel nitrate and titanium isopropoxide, to Alcohol and distilled water are dissolved in a 1:3 mixed solvent to form a solution, and nitric acid is added to form a transparent solution, and the core-shell structure NiO@TiO is obtained by one-step spray pyrolysis 2 Nano powder, although this method is simple, it cannot control the number of layers of the core-shell structure shell

Although the above methods can obtain metal oxides with a core-shell structure, they require lengthy operating procedures and expensive equipment, and cannot obtain a multi-level core-shell structure transition metal oxide with a controllable number of shell layers by a one-step method, and the simultaneous preparation process Often accompanied by the impact of by-product impurities

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