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

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 Mn 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.