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

Patent metadata

Field	Value
Publication number	US-12304812-B2
Application number	US-202017603597-A
Country	US
Kind code	B2
Filing date	Mar 9, 2020
Priority date	May 11, 2019
Publication date	May 20, 2025
Grant date	May 20, 2025

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, the hydrophobic block is a PS block, and the POMs used is one or more selected from the group consisting of phosphotungstic acid, silicomolybdic acid and phosphomolybdic acid; an ordered mesoscopic organic-inorganic composite structure is obtained by evaporation-induced self-assembly (EISA), and an ordered metal oxide semiconductor nanowire material 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 PEO-b-PS of 1-5 wt %; adding a POMs hydrate to the solvent to obtain a second transparent solution, with a concentration of POM 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 cure 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 cross-stacked 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.

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 the molecular weight 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, 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

• C01P2004/16

  Nanowires or nanorods, i.e. solid nanofibres with two nearly equal dimensions between 1-100 nanometer · CPC title

• C01G41/006

  Compounds containing tungsten, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• C01G39/02

  Oxides; Hydroxides · CPC title

• B82Y40/00 Primary

  Manufacture or treatment of nanostructures · CPC title

• C01B33/113

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