CN104944460A - Method for preparing CuAlO2 nanocrystalline - Google Patents

Abstract

The invention relates to the field of nano semiconductor mateirals, and in particular to a method for preparing CuAlO2 nanocrystalline. The method comprises the following steps: firstly, preparing fresh Cu2O and Al(OH)3 by using a precipitation method; mixing newly prepared Cu2O powder and Al(OH)3 of which the mole ratio is (1.3-2.0):1, adding deionized water, sufficiently stirring to obtain paste, adding the paste into a high-pressure reaction kettle until the filling rate is 70-75%, sealing, reacting for 15-48 hours at 350-500 DEG C, after the reaction kettle is naturally cooled to the room temperature, opening the reaction kettle, and soaking the precipitate with a diluted ammonia water solution and a diluted hydrochloric acid solution in sequence until the ammonia water solution and the diluted hydrochloric acid solution are colorless; and finally, washing with distilled water and absolute ethyl alcohol in sequence, and performing vacuum drying on obtained blue-gray powder for 2-4 hours at 50 DEG C, thereby obtaining CuAlO2 nanocrystalline.

Description

A kind of CuAlO 2nanocrystalline preparation method

Technical field

The present invention relates to nano semiconductor material field, the preparation method that particularly a kind of CuAlO2 is nanocrystalline.

Background technology

CuAlO ₂be P-type semiconductor material, direct and indirect band gap is respectively 1.8 and 3.5ev, has delafossite structure, there is d between layers of copper ¹⁰-d ¹⁰weak interaction, this interaction determines CuAlO to a great extent ₂photoelectric property.CuAlO ₂the preparation of monocrystalline has obtained certain progress, in air atmosphere, by Al ₂o ₃-Cu ₂at 1200 DEG C, CuAlO can be obtained after calcining after O ₂monocrystalline; In nitrogen atmosphere, Cu ₂o and Al ₂o ₃solid state reaction then obtained CuAlO is carried out at 1100 DEG C ₂polycrystalline.But CuAlO ₂nanocrystalline preparation also rarely has bibliographical information.The hydrothermal synthesis method that gets up of development in recent years the field such as to be prepared at monocrystalline, film and powder body material and is widely used.Hydrothermal Synthesis has reaction conditions gentleness, product purity is high, grain development is complete, even particle size distribution, controlled shape and do not need the advantages such as calcination processing.At present, Hydrothermal Synthesis has become the effective ways of preparation nano material, microporous crystal and metasable state material, and has expanded to the nanocrystalline preparation such as composite oxides, fluorochemical.

Summary of the invention

The present invention is directed to prior art Problems existing, the nanocrystalline preparation method of a kind of CuAlO2 is provided, preparation CuAlO cannot be synthesized to solve in prior art ₂nanocrystalline problem.

The object of the present invention is achieved like this, a kind of CuAlO ₂nanocrystalline preparation method, comprises the steps:

First, fresh Cu is prepared by the precipitator method ₂o and Al (OH) ₃.

Then, be the Cu of 1.3 ~ 2.0: 1 by freshly prepd, mol ratio ₂o powder and Al (OH) ₃mixing, fully stir after adding deionized water, obtain soup compound, add in autoclave by this soup compound, filling ratio is 70 ~ 75%, reacts 15 ~ 48h after sealing within the scope of 350 DEG C ~ 500 DEG C, after question response still naturally cools to room temperature, open reactor, precipitation successively with weak ammonia, dilute hydrochloric acid solution soak, until ammonia soln and hydrochloric acid soln colourless.

Finally, use distilled water and absolute ethanol washing successively, gained pewter powder, at about 50 DEG C vacuum-drying 2 ~ 4h, obtains CuAlO ₂nanocrystalline.

As a further improvement on the present invention, described temperature of reaction is 380 DEG C ~ 420 DEG C.

As a further improvement on the present invention, the described reaction times is 20 ~ 30h.

Reaction mechanism of the present invention is: with Cu ₂o and Cu ₂o is starting raw material, under hydrothermal conditions, generates CuAlO ₂nanocrystalline total reaction can be expressed as: Cu ₂o+Al (OH) ₃→ 2CuAlO ₂+ 3H ₂o (1);

The presoma used due to reaction is Al (OH) ₃, therefore in lower temperature or in the shorter time, that first carry out is Al (OH) ₃decomposition reaction: AI (OH) ₃→ γ-AlOOH → Al ₂o ₃+ H ₂o (2) then, because hydrothermal condition provides certain energy to this reaction, reacts newly-generated γ-AlOOH and Al in (2) ₂o ₃with another precursors Cu ₂o reacts, and forms product molecule layer.Reaction will proceed, and must carry out transport of substances between reactant with diffusion way by product molecule layer, but this diffusion couple most solid is slower.Reason is: the structure of (1) reaction raw materials and resultant has obvious difference; (2) formation of new nucleus needs larger atomic rearrangement, and original chemical bond must rupture, and needs new chemical bonding; (3) reaction process intermediate ion necessarily does the migration (in atom magnitude) of long distance.Diffusion between this solid-phase reactant and product nucleation process are all subject to the remarkably influenced of temperature, and temperature is higher, and spread faster, the speed of growth of nucleus is faster.Therefore, under hydrothermal conditions, only have and react the regular hour at a certain temperature, just can obtain CuAlO ₂nanocrystalline.First diffusion reaction process comprises the following steps:, Sauerstoffatom is in original nucleation sites recombine, and meanwhile, Cu and Al is by γ-AlOOH or Al ₂o ₃and Cu ₂the contact interface of O crystal grain exchanges; Next is that Cu and Al ion carries out relative diffusion by the new thing phase surface formed.In order to keep charge balance, every 3 Cu atomic diffusion cross contact interface, will have an Al atom by interfacial diffusion to another side.And temperature of reaction too low and reaction times is too short, and all can not to generate pure CuAlO2 nanocrystalline, along with γ-AlOOH or Al in product ₂o ₃the existence of phase, this is because temperature of reaction is low or the reaction times is short, all can not provide enough energy, Cu and Al is spread completely by interface.Only reach certain temperature and under the sufficiently long reaction times, just can obtain pure CuAlO2 nanocrystalline.Owing to preparing CuAlO in hydrothermal treatment consists ₂along with Al (OH) in nanocrystalline process ₃decomposition.CuAlO prepared by hydrothermal decomposition method of the present invention ₂nano-crystalline granule is even, and semiconductor property improves a lot.

Embodiment

First, fresh Cu is prepared respectively by chemical precipitation method ₂o and Al (OH) ₃each 100 grams for subsequent use.Then, be the Cu of 1.5: 1 by freshly prepd, mol ratio ₂o powder and Al (OH) ₃powder mixes, getting 100 grams, mixture inserts in beaker, add deionized water 200ml fully to stir, obtain soup compound, this soup compound is added in autoclave, filling ratio is 70%, within the scope of 380 DEG C ~ 420 DEG C DEG C, react 28h after sealing, after question response still naturally cools to room temperature, open reactor, precipitation successively with weak ammonia, dilute hydrochloric acid solution soak, until ammonia soln and hydrochloric acid soln colourless.Finally, use distilled water and absolute ethanol washing successively, gained pewter powder, at about 50 DEG C vacuum-drying 2 ~ 4h, obtains CuAlO ₂nanocrystalline.

Claims (3)

1. a CuAlO ₂nanocrystalline preparation method, comprises the steps:

First, fresh Cu is prepared by the precipitator method ₂o and Al (OH) ₃.

Then, be the Cu of 1.3 ~ 2.0: 1 by freshly prepd, mol ratio ₂o powder and Al (OH) ₃mixing, fully stir after adding deionized water, obtain soup compound, add in autoclave by this soup compound, filling ratio is 70 ~ 75%, reacts 15 ~ 48h after sealing within the scope of 350 DEG C ~ 500 DEG C, after question response still naturally cools to room temperature, open reactor, precipitation successively with weak ammonia, dilute hydrochloric acid solution soak, until ammonia soln and hydrochloric acid soln colourless.

Finally, use distilled water and absolute ethanol washing successively, gained pewter powder, at about 50 DEG C vacuum-drying 2 ~ 4h, obtains CuAlO ₂nanocrystalline.

2. CuAlO according to claim 1 ₂nanocrystalline preparation method, is characterized in that, described temperature of reaction is 380 DEG C ~ 420 DEG C.

3. CuAlO according to claim 1 ₂nanocrystalline preparation method, is characterized in that, the described reaction times is 20 ~ 30h.