CN103011281A

CN103011281A - Method for synthesizing sphere-like nano yttrium and cerium doped zirconia according to ethylene glycol sol-gel method

Info

Publication number: CN103011281A
Application number: CN2012105319353A
Authority: CN
Inventors: 李永绣; 陈萍华; 周雪珍; 唐群; 陈伟凡; 李静; 刘艳珠
Original assignee: Nanchang University
Current assignee: Ruijin Hongdu Industrial Investment Development Co Ltd
Priority date: 2012-12-12
Filing date: 2012-12-12
Publication date: 2013-04-03
Anticipated expiration: 2032-12-12
Also published as: CN103011281B

Abstract

A method for synthesizing sphere-like nano yttrium and cerium doped zirconia according to an ethylene glycol sol-gel method takes zirconium nitrate, yttrium nitrate, cerium nitrate and sodium chloride as raw materials, is a specific method used for preparing zirconia nano-crystalline with stable yttrium and cerium parts according to the ethylene glycol sol-gel method, and comprises the following steps: preparing aqueous solution containing zirconium nitrate, yttrium nitrate, cerium nitrate and sodium chloride according to the stoichiometric ratio of 96 : 3 : 1; adding ethylene glycol solution in such a manner that the ratio between the weight of ethylene glycol and the total weight of metal ions is 0.8 to 8.6; heating the mixed solution, reflowing and reacting for 1 to 12 h till sol is formed; reacting metal ions with ethylene glycol to form coordination polymer with a cross-linked structure; drying under 110 to 130 DEG C for 6 to 50 h till solid gel is obtained; washing off sodium chloride in gel with little water and alcohol; and calcining in a muffle furnace under 400 to 800 DEG C for 3 h, so as to obtain required sphere-like nano yttrium and cerium doped zirconia of which the principal crystalline phase is square phase and the particle size is about 60 nanometer.

Description

The method of the synthetic class ball shaped nano yttrium cerium doped zirconia of ethylene glycol sol-gel method

Technical field

The present invention relates to a kind of concrete grammar of the synthetic rear-earth-doped oxidation zirconium powder of class ball shaped nano body take tetragonal phase structure as principal crystalline phase, belong to Material Field.

Technical background

Zirconium white and composite oxides thereof have a wide range of applications, as: toughening ceramic, pH sensor, anode of solid oxide fuel cell, catalysis flue gas, NOx, the catalyzer of the burning such as chlorination VOC and the aspects such as sorbent material in the purification techniques.But pure zirconia in the temperature-fall period from high temperature to normal temperature because of cube-the caused huge stress of mutual conversion and volume change between four directions-monoclinic phase limited zirconic application.And the doping of some two valencys and trivalent metal ion can make zirconium white at room temperature also can have metastable four directions or Emission in Cubic, and produces the transformation toughening effect, has improved their application performance.

Zirconic crystalline phase affects structure, quality and the application performance of product consumingly.Except synthesis condition, some external conditions are also influential to zirconic crystalline phase.For example the zirconium white of Tetragonal can be directly be to be formed by the monoclinic phase zirconium white under the 37kbars at pressure under 25 ℃, this conversion is reversible, and at room temperature can not remain metastable Tetragonal.When zirconium surface exists water, SO ₄ ^2-Deng the time zirconium white is occured from Tetragonal to the monoclinic phase phase transformation, because the Y of water and specimen surface ³⁺React and form Y (OH) ₃Crystal is at Y ₂O ₃The place that content is low becomes the vantage point of monoclinic phase forming core, and phase transformation is inwardly developed from the surface, also may be that water and zirconium surface form the Zr-OH key, or Y-OH causes stress concentration and undergoes phase transition.Therefore, further study phase structure and the influence factor thereof of zirconium white and composite oxides thereof, can develop the correlation technique for the product structure controlledly synthesis.

In addition, the size of particles of synthetic product and pattern also have important impact to its application performance.Find also that in our previous work sodium-chlor has significant impact for the particle characteristic of synthesizing nano-particle.Accordingly, developed the novel method of the synthetic class nano spherical particle of salt combustion-supporting burnt together established law, and be applied some nano-metal-oxides are synthetic.

Summary of the invention

The present invention proposes a kind of salt and help sol-gel method to come the rear-earth-doped oxidation zircon ceramic of synthesis of nano powder, both utilized sodium-chlor for the improvement effect of synthetic product particle characteristic and phase structure, eliminate again sodium-chlor to the impact of crystal phase structure.

Principle of the present invention is according to the XRD of synthetic sample and SEM characterization result, has grasped the introducing of sodium-chlor to the rule that affects of product phase composition and particle characteristic.The adding of proof sodium-chlor can improve synthetic product dispersion of particles and sphericity, but the increase along with the sodium-chlor add-on, monoclinic phase content increases and the minimizing of Tetragonal content in the product, the adding that sodium-chlor is described can significantly reduce rare earth element to the stabilising effect of Tetragonal, promotes Tetragonal to the transformation of monoclinic phase.Accordingly, determined that synthetic principal crystalline phase is method and the condition of the nanometer spherical yttrium cerium doped zirconia of Tetragonal.

Processing step of the present invention is:

⑴ contain first the aqueous solution of zirconium nitrate, Yttrium trinitrate, cerous nitrate and sodium-chlor by the stoichiometric ratio preparation, wherein the ratio of the amount of substance between zirconium nitrate, Yttrium trinitrate, the cerous nitrate is 3:1:96; And the feeding quantity of sodium-chlor is the 0.5-8% of zirconium nitrate, Yttrium trinitrate, cerous nitrate gross weight;

⑵ the ratio 0.8-8.6 that press ethylene glycol and the amount of metal ion species again adds ethylene glycol solution, and with mixing solutions reflux 1h-12h, forms colloidal sol, the polycomplexation zoarium that metal ion and glycol reaction is formed have crosslinking structure;

⑶ with dry 6-50 hour of colloidal sol, obtain the solid xerogel 100-120 ℃ of temperature range;

⑷ water and ethanol flush away are placed in the muffle furnace in 400-800 ℃ of lower calcining 1-6 hour respectively with the sodium-chlor in the solid xerogel.

The invention has the beneficial effects as follows: according to the method described above, can obtain the spherical yttrium cerium of the class doped zirconia particle about 60 nanometers, principal crystalline phase is Tetragonal.And raw materials used inexpensive, low toxicity, wide material sources.

Description of drawings

The XRD diffractogram of 3 hours synthetic yttrium cerium doped zirconias of gained ethylene glycol sol-gel method of 800 ℃ of lower calcinings of Fig. 1;

The XRD diffractogram of 3 hours synthetic yttrium cerium doped zirconias of gained ethylene glycol sol-gel method of 800 ℃ of lower calcinings of Fig. 2;

Before Fig. 3 calcines whether flush away sodium-chlor on the impact relation of Tetragonal content in the synthetic product;

The SEM figure of 3 hours synthetic yttrium cerium doped zirconias of gained ethylene glycol sol-gel method of 800 ℃ of lower calcinings of Fig. 4;

The SEM figure of 3 hours synthetic yttrium cerium doped zirconias of gained ethylene glycol sol-gel method of 800 ℃ of lower calcinings of Fig. 5.

Embodiment

Embodiment 1

In round-bottomed flask, add 1mol/L yttrium nitrate solution 0.625ml, 0.4mol/L cerium nitrate solution 0.521ml, zirconium nitrate 6.7848g, deionized water 24 ml, adding ethylene glycol 1ml(ethylene glycol is 0.86 with the ratio of the amount of substance of metal ion), under magnetic agitation, make zirconium nitrate all be dissolved into clear solution.Round-bottomed flask is placed oil bath pan, connect return line, be heated under 130 ℃, reflux and form colloidal sol after 8 hours.The colloidal sol that obtains is changed in the baking oven, obtain solid gel at 110 ℃ of lower dry 12h.Then place retort furnace at 800 ℃ of lower calcining 3h.Obtained partially stabilized zirconium white (PSZ) powder.

By above-mentioned identical method, just the dosage of ethylene glycol is different, is respectively 3ml, 5ml and 10ml, and corresponding ethylene glycol is 2.58,4.30 and 8.61 with the ratio of the amount of substance of metal ion.Measure respectively XRD figure (see figure 1) and the SEM figure (see figure 4) of gained powder.Show that ethylene glycol and the ratio of the amount of substance of metal ion increase to 8.61 by 0.86, to the not obviously change of phase composition of synthetic product.

Embodiment 2

In round-bottomed flask, add 1mol/L yttrium nitrate solution 0.625ml, 0.4mol/L cerium nitrate solution 0.521ml, zirconium nitrate 6.7848g, deionized water 24 ml, adding ethylene glycol 1ml(ethylene glycol is 0.86 with the ratio of the amount of substance of metal ion), add the NaCl solid, its quality is 0.5% with the ratio of NaCl quality and nitrate total mass, makes zirconium nitrate all be dissolved into clear solution under magnetic agitation.Round-bottomed flask is placed oil bath pan, connect return line, be heated under 130 ℃, reflux and form colloidal sol after 8 hours.The colloidal sol that obtains is changed in the baking oven, obtain solid gel at 110 ℃ of lower dry 12h.Behind resulting solid gel elder generation's water and the ethanol flush away sodium-chlor wherein, then place retort furnace at 800 ℃ of lower calcining 3h.Obtained partially stabilized zirconium white (PSZ) powder.

By above-mentioned identical method, just the dosage of sodium-chlor is different, and its quality is 5.5%, 8%, 8.5%10%, 12%, 15% with the ratio of NaCl quality and nitrate total mass.The powder of gained is measured respectively its XRD figure (see figure 2) and SEM figure (see figure 5).The result shows: the principal crystalline phase of gained sample remains Tetragonal when the sodium-chlor dosage is lower than 8%, but when the sodium-chlor dosage surpassed 8%, Tetragonal content obviously descended.When the sodium-chlor dosage is increased to 10% from 5%, particle dispersed fine, size is the spherical particle about 60 nanometers evenly.The sodium-chlor dosage is low or be higher than 10% when above, and the reunion of particle is obvious.

Embodiment 3

Press the basic skills of embodiment 2, change the addition of sodium-chlor, be respectively 0.2%, 0.3%, 1.5%, 4.5%, 7.5%, 12%, and resulting solid gel do not have water and ethanol flush away sodium-chlor wherein, calcine but directly put into muffle furnace.Measure respectively the XRD figure of gained powder, the graph of a relation of its Tetragonal content and sodium-chlor dosage is seen Fig. 3, compares with the sample of calcining again behind the first flush away sodium-chlor among the embodiment 2, and its Tetragonal content obviously descends.The SEM figure of the sample that is synthesized sees Fig. 6, show that the adding of sodium-chlor can obviously improve dispersiveness and the particle sphericity of synthetic product, but dosage can not be too much, and when surpassing 7.5%, particle agglomeration is more serious.

Claims

1. a kind of ethylene glycol sol-gel method is synthesized the method for spherical nanometer yttrium cerium doped zirconia, and its processing step is:

(1) Prepare an aqueous solution containing zirconium nitrate, yttrium nitrate, cerium nitrate and sodium chloride first according to the stoichiometric ratio, wherein the ratio of the amount of substances between zirconium nitrate, yttrium nitrate and cerium nitrate is 3:1:96; The amount of sodium added is 0.5-8% of the total weight of zirconium nitrate, yttrium nitrate and cerium nitrate;

(2) Then add ethylene glycol solution according to the ratio of ethylene glycol to metal ion substance of 0.8-8.6, and heat the mixed solution to reflux for 1h-12h to form a sol, so that the metal ion and ethylene glycol react to form a cross-linked structure. Coordination polymer;

(3) Drying the sol at a temperature range of 100-120°C for 6-50 hours to obtain a solid xerogel;

(4) The sodium chloride in the solid xerogel is washed away with water and ethanol respectively, and then placed in a muffle furnace for calcination at 400-800° C. for 1-6 hours.