Ordered cross-stacked metal oxide nanowire array material and preparation method thereof

Patent metadata

Field	Value
Publication number	US-2022194793-A1
Application number	US-202017603597-A
Country	US
Kind code	A1
Filing date	Mar 9, 2020
Priority date	May 11, 2019
Publication date	Jun 23, 2022
Grant date	—

Abstract

A method for preparing an ordered cross-stacked metal oxide nanowire array is provided. The method includes the following steps: conducting synthesis by using an amphiphilic diblock copolymer as a structure directing agent, tetrahydrofuran (THF) as a solvent and polyoxometalates (POMs) as an inorganic precursor, where the diblock copolymer can interact with POMs via an electrostatic force to form a core-shell cylindrical micelle in the solvent, which self-assembles to form an ordered multilayer-crossed organic-inorganic composite nanostructure during an evaporation process; the template is removed by calcination in air, thereby obtaining ordered and crossed metal oxide nanowires with various elements doping. The nanowire array material has a high specific surface area, a high crystallinity, and realizes uniform doping of heteroatoms.

First claim

What is claimed is:

1 . A method for preparing an ordered cross-stacked metal oxide nanowire array, wherein a core-shell cylindrical micelle is formed through an electrostatic force between a hydrophilic block of an amphiphilic diblock copolymer template with a hydrophobic block having an ultra-high molecular weight and a polyoxometalates (POMs) anion, wherein the amphiphilic diblock copolymer template consists of polystyrene-block-poly(ethylene oxide) (PEO-b-PS) the hydrophilic block is a PEO block and the hydrophobic block is a PS block; an ordered mesoscopic organic-inorganic composite structure is obtained by evaporation-induced self-assembly (EISA), and an ordered metal oxide semiconductor nanowire material with a high crystallinity is obtained by carrying out calcination-induced structural transformation to remove the amphiphilic diblock copolymer template, wherein the method specifically comprises:
(1) dissolving the PEO-b-PS with a high molecular weight in a solvent, wherein the PEO-b-PS has a molecular weight M n of 15,000-35,000 g mol −1 , and stirring thoroughly to obtain a first transparent solution, with a concentration of 1-5 wt %; adding a POMs hydrate to the solvent to obtain a second transparent solution, with a concentration of 5-10 wt %; mixing the first transparent solution, and the second transparent solution, and stirring thoroughly to obtain a transparent colloidal solution; (2) transferring the colloidal solution to a petri dish to volatilize at room temperature for 2-12 h; transferring the petri dish to an oven to curing at 70-100° C. for 12-48 h to obtain a transparent organic-inorganic composite film, scraping the transparent organic-inorganic composite film from the petri dish, and grinding to obtain powder; and (3) placing the powder in a tube furnace, and calcinating the powder in nitrogen for 1-2 h by heating up to 350-500° C. at a rate of 1-3° C./min to obtain a sample; calcinating the sample in air at 400-450° C. for 0.5-1 h, removing carbon therein to obtain a crystalline crossed metal oxide nanowire material.

2 . The method according to claim 1 , wherein in step (1), the solvent used is one or more selected from the group consisting of tetrahydrofuran (THF), toluene, chloroform and dimethylformamide; a molecular weight of the PEO block of the amphiphilic diblock copolymer is 2,000-5,000 g/mol, and a molecular weight of the PS block is 10,000-30,000 g/mol; the POMs used is one or more selected from the group consisting of silicotungstic acid, phosphotungstic acid, silicomolybdic acid and phosphomolybdic acid.

3 . The method according to claim 2 , wherein an array spacing and a nanowire diameter of the crystalline crossed metal oxide nanowire material are controlled by changing lengths of the PS block and the PEO block of the amphiphilic diblock copolymer, respectively.

4 . The method according to claim 2 , wherein metal oxide nanowire materials, composed of different elements, with a high crystallinity and a high specific surface area, or bimetal or multi-metal composite oxide materials are synthesized by using different oxometallate hydrates as inorganic precursors.

5 . An ordered cross-stacked metal oxide nanowire array material prepared by using the method according to claim 1 .

6 . The ordered cross-stacked metal oxide nanowire array material according to claim 5 , wherein in step (1), the solvent used is one or more selected from the group consisting of tetrahydrofuran (THF), toluene, chloroform and dimethylformamide; a molecular weight of the PEO block of the amphiphilic diblock copolymer is 2,000-5,000 g/mol, and a molecular weight of the PS block is 10,000-30,000 g/mol; the POMs used is one or more selected from the group consisting of silicotungstic acid, phosphotungstic acid, silicomolybdic acid and phosphomolybdic acid.

7 . The ordered cross-stacked metal oxide nanowire array material according to claim 6 , wherein an array spacing and a nanowire diameter of the crystalline crossed metal oxide nanowire material are controlled by changing lengths of the PS block and the PEO block of the amphiphilic diblock copolymer, respectively.

8 . The ordered cross-stacked metal oxide nanowire array material according to claim 6 , wherein metal oxide nanowire materials, composed of different elements, with a high crystallinity and a high specific surface area, or bimetal or multi-metal composite oxide materials are synthesized by using different oxometallate hydrates as inorganic precursors.

Assignees

• Univ Fudan

Inventors

• Deng Yonghui
• Ren Yuan
• Zou Yidong

Classifications

• C01B33/113

  Silicon oxides; Hydrates thereof {(preparing monoxide by reduction of siliceous material C01B33/182)} · CPC title

• C01B25/16

  Oxyacids of phosphorus; Salts thereof (peroxyacids or salts thereof C01B15/00) · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• B82Y40/00 Primary

  Manufacture or treatment of nanostructures · CPC title

• C01B13/185 Primary

  Preparing mixtures of oxides · CPC title