CN101362606A

CN101362606A - K2Mo3O10.3H2O nano-wire preparation method

Info

Publication number: CN101362606A
Application number: CNA2008101197702A
Authority: CN
Inventors: 薛炯微; 张凯; 吴湛; 龚巍巍; 许胜勇
Original assignee: Peking University
Current assignee: Peking University
Priority date: 2008-09-09
Filing date: 2008-09-09
Publication date: 2009-02-11
Anticipated expiration: 2028-09-09
Also published as: CN100594185C

Abstract

The invention discloses a preparation method of potassium trimolybdate nanowires, and belongs to the field of nano-technology and the artificial crystallogphy. The preparation method prepares the potassium trimolybdate trihydrate nanowires through the reaction of hexaammonium molybdate tetrahydrate and potassium ions in water. The reactants are preferentially heated to the range from 30 DEG C to 90 DEG C through a water bath before the reaction. The reaction can be carried out under the water bath condition for about 4 to 5 minutes or be carried out during the natural cooling process after the heating by the water bath for 3 to 5 minutes. The obtained potassium trimolybdate trihydrate nanowires are preferentially cleaned after the completion of the reaction, and the lasting time of the cleaning process is less than the time which is needed by the majority of the nanowires from the swelling stage to the dissolution stage. Compared with the prior art, the method has the advantages of high crystal purity of products, uniform thickness of the nanowires, larger length-diameter, simple needed instruments, rapid preparation, ability of being applicable to mass production, and the like.

Description

A kind of preparation method of three hydrations, three potassium molybdate nano wires

Technical field

The present invention relates to a kind of preparation method of three potassium molybdate nano wires, belong to nanotechnology, artificial lens field.

Background technology

The poly-polyoxometallic acid salt compound that contains molybdenum can be used as catalyzer, all has a wide range of applications at aspects such as surface catalysis, chemical analysis, biological chemistry and clinical treatments.K wherein ₂Mo ₃O ₁₀Be exactly a kind of laser crystal growth catalyzer (L.L.Tian of excellent performance, J.Y.Wang, Q.C.Guan, J.Q.Wei, H.F.Pan, Y.G.Liu " Study on Growth andOptical Properties of YbYAB Crystal ", J.Chin.Rare Earth Soc., 2,172-175 (1999)), it can pass through K very simply ₂Mo ₃O ₁₀3H ₂O sloughs crystal water and obtains.K in addition ₂Mo ₃O ₁₀Nano wire has good solvability, and the preparation method is simple, quick, is also having very big application prospect aspect the preparation of nano-channel.

The method for preparing nano wire mainly contains template, chemical Vapor deposition process, liquid phase synthesizing method etc.And synthetic simple being suitable for of liquid phase.The isopoly-acid salt of molybdenum has a lot of poly-polyacid root forms in solution, use for a long time molybdic acid is carried out the method preparation (W.Laocha that acidifying (acidification) is handled, J.Jansen, and H.Schenk, " Crystal Structure ofFibrillar Potassium Trimolybdate K ₂Mo ₃O ₁₀3H ₂O by Direct Method/Powder DiffractionPackage ", J.Solid State Chem.115,225-228 (1995)).Because the acid ion that forms in the preparation process and the concentration and the pH value of solution are in close relations, and these several ions are difficult to differentiate, and cause preparation technology's difficulty.

Summary of the invention

The present invention is intended to overcome problems of the prior art, and a kind of simple efficient production K is provided ₂Mo ₃O ₁₀3H ₂The method of O nano wire.

In order to achieve the above object, the present invention adopts following technical scheme:

The present invention by four hydration Ammonium Heptamolybdates in water and potassium ion prepared in reaction three hydrations three potassium molybdate nano wires.Preferably before reaction with reactant by heating in water bath to 30 ℃ in 90 ℃ scope, more preferably about 70 ℃.At this warm area, speed of response was very fast when temperature was higher, and speed of response reduced when temperature was low.About 1-5 of reaction times minute, resulting nano wire even thickness, length-to-diameter ratio is big, and platelet is few.

Reactant four hydration Ammonium Heptamolybdates wherein and the ratio of the amount of substance between the potassium ion are preferred in 1:10 arrives the scope of 3:1, more preferably 1:3.

Described four hydration Ammonium Heptamolybdates are dissolved in described four hydration Ammonium Heptamolybdates and inorganic potassium salt in the deionized water by described heating in water bath in water and before potassium ion reacts.Described inorganic potassium salt is selected from one or more in the set of being made up of Repone K, saltpetre, vitriolate of tartar, Potassium Bromide, potassiumiodide and potassium sulphide.

The reaction of described four hydration Ammonium Heptamolybdates and potassium ion can be carried out under above-mentioned water bath condition, continues about 4-5 minute; Also can carry out in the natural temperature-fall period behind heating in water bath, continue about 3-5 minute.

After described reaction is finished, preferably three hydrations, the three potassium molybdate nano wires that obtain are cleaned, the time that described cleaning process continues enters the required time of dissolution phase less than most of nano wire by the swelling stage.Though K ₂Mo ₃O ₁₀3H ₂The O nano wire is water-soluble, but as polymkeric substance, the velocity of diffusion in solvent much smaller than other small ions, so can utilize this velocity contrast, is washed it.K ₂Mo ₃O ₁₀3H ₂The dissolution process of the dissolution process of O nano wire and other crystallization polymer fibers is very similar, is divided into swelling and two stages of dissolving.As long as therefore guarantee that washing time is controlled at most of nano wires and also is in the swelling stage, just can realize a large amount of nano wires that not run off, the also competent purpose of washing that defecates.

Preferably, can three hydrations, the three potassium molybdate nano wires that obtain repeatedly be cleaned, and use centrifugal and/or method of pumping filtration in cleaning process, wherein the centrifugal cleaning performance is better.

Compare with prior art, this patent new preparation process has that product crystal purity height, nano wire even thickness, bigger, the required instrument of length-to-diameter ratio are simple, preparation fast, be fit to advantage such as scale operation.

Description of drawings

Fig. 1 be three hydrations, the three potassium molybdate nano wires that make of embodiment 1 the XRD spectrum and with the contrast of standard spectrum;

Fig. 2 is the SEM shooting figure of three hydrations, the three potassium molybdate nano wires that make of embodiment 2.

Embodiment

Below in conjunction with Figure of description and specific embodiment the inventive method is described better.

Embodiment 1

Present embodiment adopts following step to prepare three hydrations, three potassium molybdate nano wires:

1. with 1.2 gram (NH ₄) ₆Mo ₇O ₂₄4H ₂99.999%) and 0.4 gram KCl (purity: 99.999%) put into beaker, add 8 milliliters of deionized waters, at room temperature mixed dissolution O (purity:;

2. place 70 ℃ water bath, cross 30 seconds left and right sides solution and become clarification from muddiness; To about 60 seconds, settled solution begins to become turbid, and expression begins to generate target product;

3. take out beaker from water bath, place cooling under the room temperature condition, in the process of cooling, solution becomes muddiness from clarification, and whole process is approximately 3-5 minute, and this process promptly is the process of growth of nano wire;

4. rock turbid liquid, floss occurs and assemble agglomerating phenomenon, be separated with the fining end branch; Filtration or this floss of centrifugal acquisition promptly obtain K ₂Mo ₃O ₁₀3H ₂O nano wire crude product.

In this crude product, except K ₂Mo ₃O ₁₀3H ₂Outside the O nano wire (account for crude product total mass 40%), also contain K+, NH ₄ ⁺, Mo ₃O ₁₀ ^2-Deng impurity, preferably it is done conventional aftertreatment to be further purified product, remove impurity.Wherein further clean is comparatively necessary, otherwise the nano wire of gained can be hardened by platelet.

Present embodiment adopts following purging method:

Wash above-mentioned crude product on a small quantity, fast with deionized water, guarantee that washing time is controlled at most of nano wires and also is in the swelling stage,, reach the purpose of cleaning simultaneously with a large amount of nano wires of Anti-lost;

The water-fast K of the washing centrifugal recovery in back ₂Mo ₃O ₁₀3H ₂The O nano wire;

K to the acquisition of centrifugal back ₂Mo ₃O ₁₀3H ₂The O nano wire is purified again according to above-mentioned steps, altogether through 6 times centrifugal after, the K that obtains ₂Mo ₃O ₁₀3H ₂The O nanowire product accounts for 95% of total mass greatly.

Embodiment 2

The present embodiment preparation process is identical with embodiment 1, and difference is:

In step 3, present embodiment continues reacting by heating solution under water bath condition, can observe, and amount of solid increases sharply, and liquid component reduces rapidly, and whole process continues about 4 to 5 minutes, waits only to remain to stop heating when seldom measuring solution, enters step 4.

The present embodiment method is compared with embodiment 1 method, and the nano wire that present method obtains is thicker more even.

After obtaining the crude product nano wire, further purify according to the post-treating method of embodiment 1.

The nano wire that obtains is made following sign:

Detect the XRD figure of end product composes as shown in Figure 1 with X-ray diffraction method, as seen, this collection of illustrative plates and computation model card JCPDS 83-0325 (W.Laocha, J.Jansen, and H.Schenk, " Crystal Structure of Fibrillar PotassiumTrimolybdate K ₂Mo ₃O ₁₀3H ₂O by Direct Method/Powder Diffraction Package ", J.Solid StateChem.115,225-228 (1995)) coincide better, among the figure, isolating straight line is represented the position and the intensity of the general diffraction peak of standard.

Can also calculate lattice parameter from figure is

,

,

, β=90 °.This collection of illustrative plates also shows simultaneously, and the purity of sample is very high, the preparation method (Hodorowicz, Rocz.Chem.50,1031 (1976)) before being far superior to.

Fig. 2 has shown the image that obtains with scanning electronic microscope (SEM) observation end product, this figure shows the diameter of gained nano wire between 20-200nm, and maximum length illustrates that greater than 150 μ m the surface of these nano wires is very smooth, even thickness, growth orientation are [100] direction.

Claims

1. the preparation method of hydration three potassium molybdate nano wires is characterized in that, reaction obtains with potassium ion in water by four hydration Ammonium Heptamolybdates.

2. the method for claim 1 is characterized in that, before described reaction with the reactant of described reaction by heating in water bath to 30 ℃ in 90 ℃ temperature range.

3. the method for claim 1 is characterized in that, before described reaction with the reactant of described reaction by heating in water bath to 70 ℃.

4. as claim 2 or 3 described methods, it is characterized in that described being reflected under the described bath temperature carried out, the reaction times of described reaction is in 4 minutes to 5 minutes scope.

5. as claim 2 or 3 described methods, it is characterized in that, described being reflected at by carrying out in the described bath temperature nature temperature-fall period, the reaction times of described reaction is in 3 minutes to 5 minutes scope.

6. the method for claim 1 is characterized in that, the amount of substance between described four hydration Ammonium Heptamolybdates and the potassium ion is than in 1:10 arrives the scope of 3:1.

7. as claim 1 or 6 described methods, it is characterized in that the amount of substance between described four hydration Ammonium Heptamolybdates and the potassium ion is than being 1:3.

8. the method for claim 1 is characterized in that, described potassium ion comes from and is selected from the set of being made up of Repone K, saltpetre, vitriolate of tartar, Potassium Bromide, potassiumiodide and potassium sulphide one or more.

9. the method for claim 1 is characterized in that, after described reaction is finished, three hydrations, the three potassium molybdate nano wires that obtain is cleaned, and the time that described cleaning process continues enters the required time of dissolution phase less than most of nano wire by the swelling stage.

10. method as claimed in claim 9 is characterized in that, after described reaction is finished, three hydrations, the three potassium molybdate nano wires that obtain is repeatedly cleaned, and use centrifugal and/or method of pumping filtration in cleaning process.