CN1206027C - Cerium-base ternary nano level composite RE oxide and its prepn process - Google Patents
Cerium-base ternary nano level composite RE oxide and its prepn process Download PDFInfo
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- CN1206027C CN1206027C CN 02130892 CN02130892A CN1206027C CN 1206027 C CN1206027 C CN 1206027C CN 02130892 CN02130892 CN 02130892 CN 02130892 A CN02130892 A CN 02130892A CN 1206027 C CN1206027 C CN 1206027C
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Abstract
The present invention relates to a cerium-base ternary nanometer level composite RE oxide and a preparation method thereof. The RE composite oxide provided by the present invention is a solid solution of cerium oxide, zirconium oxide and lanthanum oxide, which comprises chemical components of 20 to 40 wt% of CeO2, 50 to 70 wt% of ZrO and 1 to 10 wt% of La2O3. Inorganic salt is used as a raw material of the cerium-base ternary nanometer level composite RE oxide, and the preparation of the cerium-base ternary nanometer level composite RE oxide is together completed by a sol-gel method and a coprecipitation method or is together completed by a coating method and the coprecipitation method. The preparation of the cerium-base ternary nanometer level composite RE oxide has no discharge of three-waste, and reactions are all carried out under a room temperature condition. Thus, the present invention has the advantages of simple preparation method and lower production cost. Indicated by the thermal treatment of low temperature (650 DEG C) or high temperature (1000 DEG C), both the specific surface area and the high temperature thermal stability of the provided CeO2-ZrO2-La2 O3 composite oxide are obviously enhanced compared with that of the prior art. Thus, thecerium-base ternary nanometer level composite RE oxide and a preparation method thereof can be used for catalytic processes of various reactions, and are particularly suitable for the purification treatment of automobile exhaust gas.
Description
Technical field
The present invention relates to a kind of complex rare-earth oxidate containing valuable metal and preparation method thereof, relate in particular to ternary nano level complex rare-earth oxidate containing valuable metal of a kind of cerium-based and preparation method thereof; Can be applicable to the catalytic process of multiple reaction,, be specially adapted to purifying vehicle exhaust and handle as exhaust-gas treatment, hydrocarbon or other organic dehydrocyclization of hydrogenation sulfuration, hydrodenitrogeneration, dehydrohalogenation, internal combustion engine.
Background technology
Automobile is the sign of modern civilization, and its appearance has greatly promoted development of human society and progress.But when bringing convenience to people's life, it also brings many serious problems to the mankind, and as noise, noxious gas emission etc., vehicle exhaust has become the primary pollution source of urban atmosphere.Along with the requirement of sustainable development and the enhancing of people's environmental consciousness, automobile blowdown control is imperative, and catalytic cleaning of car tail gas then is to reduce harmful exhaust to discharge one of valid approach the most.Administer vehicle exhaust the effective way of the pollution of environment is to use the catalytic cleaning of car tail gas device.At present, single tetragonal structure cerium oxide and zirconium oxide compound is the primary raw material of automotive exhaust catalysis reforming unit, has an effect mainly as catalyst aid.
Cerium oxide is an important component in the three-way catalyst (TWC) of purifying vehicle exhaust, mainly is because cerium Ce
3+And Ce
4+Between have reversible conversion, have good oxygen storage capacity (OSC).Cerium oxide discharges oxygen easily under reducing condition, make CO and CH
xOxidation; Under oxidizing condition, store oxygen, so that NO
xReduction; Thereby near the fluctuation of the atmosphere the control noble metal, the purification activity of maintenance catalyst, this function needs CeO
2With noble metal synergy competence exertion, if CeO
2Particulate increases will cause CeO
2Thereby the increase of surface noble metal crystal grain reduces CeO
2Oxygen storage capacity (OSC).People such as FornasieroP discover the purer CeO of the heat endurance of Ce-Zr solid solution
2Height, and add Zr
4+Can increase CeO
2The mobility of middle oxygen reduces Ce
4+The reduction activation energy, reduce the initial reduction temperature of body phase, thereby make Ce-Zr have higher storage oxygen/put the oxygen ability (to see Fornasiero P for details, Di Monte R, Ranga Rao G.Rh-loaded CeO
2-ZrO
2Solidsolutions as highly efficient oxygen exchangers:dependence of the reduction behavior and theoxygen storage capacity on the structural properties[J] .J Catal, 1995,151 (1): 168-177) people such as .ChristineB research, at CeO
2The middle ZrO that adds
2, CeO
2-ZrO
2Specific area is apparently higher than CeO
2, at 700 ℃ after aging 6 hours, its specific area is 70m
2/ g, at 1000 ℃ after aging 6 hours, its specific area is 8m
2/ g (see ChristineB for details, Francois G.Characterisation of ceria-zirconia solid solutions after hydrothermalageing[J] .Applied Catalysis A, 2001,220:69-77).
But, because the oxidation-reduction reaction of three-way catalyst mainly is to occur in catalyst surface.High-specific surface area, high high-temp stability are the prerequisites that cerium oxide has high oxygen storage power (OSC).Therefore be necessary on the basis of forefathers' research, further to improve the specific area and the high high-temp stability of cerium oxide.
Summary of the invention
The object of the invention provides ternary nano level rare earth oxide of a kind of cerium-based and preparation method thereof, with co-catalyst cerium oxide (CeO
2) be prepared as superfine powder, thereby the catalytic performance that improves cerium oxide with and oxygen storage capacity, add other Zr simultaneously therein
4+, La
3+Ion is with refinement CeO
2Crystal grain is prepared into nano rare earth composite oxide; In the hope of obtaining under hot conditions, to have the co-catalyst of high specific surface area and Heat stability is good.
Technical scheme of the present invention is as follows:
A kind of ternary nano level complex rare-earth oxidate containing valuable metal of cerium-based, this complex rare-earth oxidate containing valuable metal are the solid solution of cerium oxide, zirconia and lanthana, its developed by molecule formula: CeO
2-ZrO
2-La
2O
3Its chemical composition:
CeO
2：20-40wt％，ZrO
2：50-70wt％，La
2O
3：1-10wt％；
The invention provides a kind of method for preparing the ternary nano level complex rare-earth oxidate containing valuable metal of above-mentioned cerium-based, finished jointly by sol-gal process and coprecipitation, its concrete preparation process is as follows:
(1) at ambient temperature, dissolve cerium salt, zirconates, lanthanum salt respectively, be prepared into cerous nitrate, zirconium nitrate and lanthanum nitrate hexahydrate respectively with rare nitric acid;
(2) according to proportioning components, get above-mentioned solution, be prepared into and contain Ce
3+, Zr
4+And La
3+The mixed nitrate solution of ion under lasting the stirring, is added to the surfactant that accounts for mixed nitrate solution 1-5vol% in the described mixed solution;
(3) then precipitating reagent is added in the mixed solution, or mixed solution is added in the precipitating reagent, the pH value is controlled at 4.5-11 in the course of reaction, and the reaction time is 40-80 minute, obtains white depositions;
(4) white depositions is spent deionised water, calcined 1-3 hour down at 400-700 ℃ then.
The present invention also provides the method for the ternary nano level complex rare-earth oxidate containing valuable metal of the above-mentioned cerium-based of another kind of preparation, this method is finished jointly by coating method and coprecipitation, its concrete preparation process is as follows: (1) at ambient temperature, dissolve zirconates, lanthanum salt respectively with rare nitric acid, make zirconium nitrate and lanthanum nitrate hexahydrate respectively;
(1) according to proportioning components, get above-mentioned each solution, be prepared into and contain Zr
4+And La
3+The mixed nitrate solution of ion;
(2) at ambient temperature, the cerous carbonate solid is added in the precipitating reagent, adds the surfactant that accounts for mixed nitrate solution 1-5vol% then, stirred 30-60 minute;
(3) under stirring condition, the mixed nitrate solution in the step (2) is joined in the solution in the step (3), the pH value is controlled at 5.5-10 in the course of reaction, and the reaction time is 40-80 minute; Obtain white depositions,
(4) white depositions spends deionised water, calcines 1-3 hour down at 400-700 ℃ then.
Cerium salt described in the present invention is any in cerous carbonate, cerium ammonium nitrate, the cerous nitrate, and described zirconates is any in zirconium oxychloride, zirconium nitrate, the zirconyl nitrate; Described lanthanum salt adopts lanthanum nitrate; Prepared cerous nitrate solution concentration is that 0.3-0.5M, zirconium nitrate solution concentration are that 0.3-0.5M and lanthanum nitrate hexahydrate concentration are 0.5M.
Precipitating reagent described in the present invention is solubility hydroxide, soluble carbon hydrochlorate or ammoniacal liquor.
The surfactant that is added among the present invention can adopt any in polysorbas20, polysorbate60, span 80, polyvinyl alcohol 20000, dodecyl sodium sulfate or the cetyl chloride ammonium.
The present invention is owing to adopt inorganic salts as reaction raw materials, and the no three wastes produce, and reacts and all carry out at ambient temperature, so the preparation method is simple, and production cost is lower; The CeO that is provided
2-ZrO
2-La
2O
3Composite oxides, through heat treatment in 650 ℃, 4 hours, specific area was 90-110m
2/ g, their primary particle size are all in the 10-20nm scope; Through heat treatment in 1000 ℃, 4 hours, specific area was 25-35m
2/ g; Their primary particle size is all in the 20-30nm scope.
Description of drawings
Fig. 1 is CeO
2-ZrO
2-La
2O
3The XRD figure of (part by weight by oxide is 30/60/10 separately) composite oxides after through heat treatment in 1000 ℃, 4 hours.
The specific embodiment
Any obtaining that cerium ion can be from cerous carbonate, cerium ammonium nitrate, cerous nitrate among the present invention; Zirconium ion can be from zirconium oxychloride, zirconium nitrate, zirconyl nitrate any obtaining; Lanthanum ion obtains from lanthanum nitrate.
Selected precipitating reagent can be soluble carbon hydrochlorate or ammoniacal liquor.The surfactant that adds can be polysorbas20, polysorbate60, span 80, polyvinyl alcohol 20000, dodecyl sodium sulfate, cetyl chloride ammonium.
The above-mentioned material source is the commercial goods.
Embodiment 1:(method 1)
Be respectively the polysorbate60 of interpolation 1vol% in 0.3M cerous nitrate, 0.3M zirconium nitrate and the 0.5M lanthanum nitrate mixed solution (part by weight by oxide is 30/60/10 separately) in above-mentioned mixed solution to concentration, under stirring condition, mixed solution is added in the ammonium bicarbonate soln, the pH value is controlled at 7.5, reaction time is 60 minutes, generates white precipitate; Filter this sediment, calcined 2 hours down at 600 ℃ then, its specific area is 130.5m
2/ g.Calcined respectively under 650 ℃, 1000 ℃ 4 hours then, its specific area is respectively 98.3m
2/ g and 28m
2/ g.
Fig. 1 is CeO
2-ZrO
2-La
2O
3The XRD figure of (part by weight by oxide is 30/60/10 separately) composite oxides after through heat treatment in 1000 ℃, 4 hours.As can be seen from the figure the oxide that is obtained exists with pure solid solution form, does not have other dephasign to produce, and shows this kind oxide high-temperature Heat stability is good.Small angle X-ray diffraction is analyzed this sample after calcining 4 hours under 650 ℃, its medium particle diameter d
50Be 12.4nm, after calcining 4 hours under 1000 ℃, d
50Be 26.5nm.
Embodiment 2:(method 1)
To concentration is to add the span 80 of 5vol% in 0.3M cerous nitrate, 0.3M zirconium nitrate and the 0.5M lanthanum nitrate mixed solution (part by weight by oxide is 40/55/5 separately) in above-mentioned mixed solution, under stirring condition, mixed solution is added in the concentrated ammonia liquor, the pH value is controlled at 11, reaction time is 40 minutes, generates white precipitate; Filter this sediment, calcined 2 hours down at 600 ℃ then, its specific area is 130m
2/ g.Calcined respectively under 650 ℃, 1000 ℃ 4 hours, its specific area is 101.1m
2/ g and 26.5m
2/ g.
X-ray diffraction analysis shows that there be (X ray diffracting spectrum is consistent with Fig. 1, so slightly) in the oxide that is obtained with pure solid solution phase form.Small angle X-ray diffraction is analyzed this sample after calcining 4 hours under 650 ℃, its medium particle diameter d
50Be 13.8nm, after calcining 4 hours under 1000 ℃, d
50Be 29.5nm.
Embodiment 3:(method 2)
Under stirring condition, in the zirconium nitrate solution of 0.5M, add the 0.5M lanthanum nitrate hexahydrate, be prepared into mixed solution (weight ratio of cerium oxide, zirconia and lanthana is 30/60/10); Then the cerous carbonate solid is joined in the sal volatile, and in solution, add the 5vol% dodecyl sodium sulfate, stirred 30 minutes; Under stirring condition, the nitric acid mixed liquor is joined in the above-mentioned precipitating reagent suspension, the pH value is controlled at 8.5, and the reaction time is 80 minutes, generates white precipitate; Filter this sediment, calcined 2 hours down at 600 ℃ then.Calcined respectively under 650 ℃, 1000 ℃ 4 hours, its specific area is 108m
2/ g and 32.5m
2/ g.
X-ray diffraction analysis shows that there be (X ray diffracting spectrum is consistent with Fig. 1, so slightly) in the oxide that is obtained with pure solid solution phase form.Small angle X-ray diffraction is analyzed this sample after calcining 4 hours under 650 ℃, its medium particle diameter d
50Be 18.2nm, after calcining 4 hours under 1000 ℃, d
50Be 28.8nm.
Embodiment 4:(method 2)
Under stirring condition, in the zirconium nitrate solution of 0.5M, add the 0.5M lanthanum nitrate hexahydrate, be prepared into mixed solution (weight ratio of cerium oxide, zirconia and lanthana is 20/70/10); Then the cerous carbonate solid is joined in the sal volatile, and in solution, add 5vol% polyvinyl alcohol 20000, stirred 50 minutes; Under stirring condition, zirconium nitrate lanthanum mixed liquor is joined in the above-mentioned precipitating reagent suspension, the pH value is controlled at 10, and the reaction time is 40 minutes, generates white precipitate; Filter this sediment, calcined 3 hours down at 400 ℃ then.Calcined respectively under 650 ℃, 1000 ℃ 4 hours, its specific area is 101.25m
2/ g and 28.5m
2/ g.
X-ray diffraction analysis shows that there be (X ray diffracting spectrum is consistent with Fig. 1, so slightly) in the oxide that is obtained with pure solid solution phase form.Small angle X-ray diffraction is analyzed this sample after calcining 4 hours under 650 ℃, its medium particle diameter d
50Be 15.6nm, after calcining 4 hours under 1000 ℃, d
50Be 26.5nm.
Embodiment 5:(method 2)
Under stirring condition, in the zirconium nitrate solution of 0.4M, add the 0.5M lanthanum nitrate hexahydrate, be prepared into mixed solution (weight ratio of cerium oxide, zirconia and lanthana is 40/59/1); Then the cerous carbonate solid is joined in the sal volatile, and in solution, add 1vol% cetyl chloride ammonium, stirred 60 minutes; Under stirring condition, zirconium nitrate lanthanum mixed liquor is joined in the above-mentioned precipitating reagent suspension, the pH value is controlled at 5.5, and the reaction time is 60 minutes, generates white precipitate; Filter this sediment, calcined 1 hour down at 700 ℃ then.Calcined respectively under 650 ℃, 1000 ℃ 4 hours, its specific area is 95.3m
2/ g and 25.5m
2/ g.
X-ray diffraction analysis shows that there be (X ray diffracting spectrum is consistent with Fig. 1, so slightly) in the oxide that is obtained with pure solid solution phase form.Small angle X-ray diffraction is analyzed this sample after calcining 4 hours under 650 ℃, its medium particle diameter d
50Be 19.6nm, after calcining 4 hours under 1000 ℃, d
50Be 29.8nm.
Comparing embodiment:
People such as Christine B research, (weight ratio by oxide is 67/33 separately) adds excess of ammonia water in the mixed liquor of cerous nitrate and zirconyl nitrate, at 700 ℃ after aging 6 hours, CeO
2-ZrO
2Specific area is 70m
2/ g, at 900 ℃ after aging 6 hours, its specific area is 26m
2/ g, at 1000 ℃ after aging 6 hours, its specific area is 8m
2/ g (see ChristineB for details, Francois G.Characterisation of ceria-zirconia solid solutions after hydrothermalageing[J] .Applied Catalysis A, 2001,220:69-77).
Utilize the prepared composite oxides that go out of the embodiment of the invention 600 ℃ of calcinings 2 hours down, its specific area is 130m
2/ g.Calcined respectively under 700 ℃, 1000 ℃ 6 hours, its specific area is 90.5m
2/ g and 15.5m
2/ g.
From then in the example as can be seen, by changing component and adding lanthanum ion the specific area of composite oxides is all increased under low temperature and hot conditions than people's such as Christine B achievement in research.
Claims (8)
1. the ternary nano level complex rare-earth oxidate containing valuable metal of a cerium-based, it is characterized in that: this complex rare-earth oxidate containing valuable metal is the solid solution of cerium oxide, zirconia and lanthana, its developed by molecule formula: CeO
2-ZrO
2-La
2O
3Its chemical composition:
CeO
2：20-40wt％，ZrO
2：50-70wt％，La
2O
3：1-10wt％。
2. one kind prepares the method for complex rare-earth oxidate containing valuable metal according to claim 1, it is characterized in that this method carries out as follows:
(1) at ambient temperature, dissolve cerium salt, zirconates, lanthanum salt respectively, be prepared into cerous nitrate, zirconium nitrate and lanthanum nitrate hexahydrate respectively with rare nitric acid;
(2) according to proportioning components, get above-mentioned solution, be prepared into and contain Ce
3+, Zr
4+And La
3+The mixed nitrate solution of ion under lasting the stirring, is added to the surfactant that accounts for mixed nitrate solution 1-5vol% in the described mixed solution;
(3) then precipitating reagent is added in the mixed solution, or mixed solution is added in the precipitating reagent, the pH value is controlled at 4.5-11 in the course of reaction, and the reaction time is 40-80 minute, obtains white depositions;
(4) white depositions is spent deionised water, calcined 1-3 hour down at 400-700 ℃ then.
3. according to the preparation method of the described complex rare-earth oxidate containing valuable metal of claim 2, it is characterized in that: prepared cerous nitrate solution concentration is that 0.3-0.5M, zirconium nitrate solution concentration are that 0.3-0.5M and lanthanum nitrate hexahydrate concentration are 0.5M.
4. according to the preparation method of the described complex rare-earth oxidate containing valuable metal of claim 2, it is characterized in that: the cerium salt described in the step (1) is any in cerous carbonate, cerium ammonium nitrate, the cerous nitrate, and described zirconates is any in zirconium oxychloride, zirconium nitrate, the zirconyl nitrate; Described lanthanum salt adopts lanthanum nitrate.
5. according to the preparation method of the described complex rare-earth oxidate containing valuable metal of claim 2, it is characterized in that: the precipitating reagent described in the step (3) is soluble carbon hydrochlorate or ammoniacal liquor.
6. according to the preparation method of the described complex rare-earth oxidate containing valuable metal of claim 2, it is characterized in that: described surfactant can be any in polysorbas20, polysorbate60, span 80, polyvinyl alcohol 20000, dodecyl sodium sulfate or the cetyl chloride ammonium.
7. one kind prepares the method for complex rare-earth oxidate containing valuable metal according to claim 1, and it is characterized in that: this method is carried out as follows:
(1) at ambient temperature, dissolve zirconates, lanthanum salt respectively, make zirconium nitrate and lanthanum nitrate hexahydrate respectively with rare nitric acid;
(2) according to proportioning components, get above-mentioned each solution, be prepared into and contain Zr
4+And La
3+The mixed nitrate solution of ion;
(3) at ambient temperature, the cerous carbonate solid is added in the precipitating reagent, adds the surfactant that accounts for mixed nitrate solution 1-5vol% then, stirred 30-60 minute;
(4) under stirring condition, the mixed nitrate solution in the step (2) is joined in the solution of step (3), the pH value is controlled at 5.5-10 in the course of reaction, and the reaction time is 40-80 minute, obtains white depositions;
(5) white depositions is spent deionised water, calcined 1-3 hour down at 400-700 ℃ then.
8. according to the preparation method of the described complex rare-earth oxidate containing valuable metal of claim 7, it is characterized in that: the zirconium nitrate solution concentration described in the step (1) is 0.3-0.5M, and lanthanum nitrate hexahydrate concentration is 0.5M.
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Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1297479C (en) * | 2004-08-17 | 2007-01-31 | 山东师范大学 | Preparation method of nanometer ball |
| CN100479919C (en) * | 2005-11-21 | 2009-04-22 | 中国科学院长春应用化学研究所 | Anti-high temperature sintered catalyst carrier materia, and preparing method and use thereof |
| JP4265626B2 (en) * | 2006-07-12 | 2009-05-20 | トヨタ自動車株式会社 | Catalyst carrier particles, method for producing the same, and exhaust gas purification catalyst |
| CN102395643B (en) | 2009-04-15 | 2013-12-18 | 罗地亚（中国）投资有限公司 | Cerium-based particle composition and preparation thereof |
| CN101992083B (en) * | 2010-10-27 | 2013-01-02 | 重庆海特汽车排气系统有限公司 | Composite cerium-zirconium solid solution with high oxygen storage capability and preparation method thereof |
| JP5805986B2 (en) | 2011-04-22 | 2015-11-10 | 三井金属鉱業株式会社 | Carrier for internal combustion engine exhaust gas purification catalyst |
| CN102744074A (en) * | 2012-07-10 | 2012-10-24 | 江苏高淳陶瓷股份有限公司 | Oxygen storage material for catalytic purification of automobile exhaust and preparation method of oxygen storage matrial |
| CN103623807A (en) * | 2013-12-10 | 2014-03-12 | 江南大学 | Preparation method for novel doped nano-zirconia catalyst |
| CN105642269B (en) * | 2016-02-26 | 2018-07-27 | 江西国瓷博晶新材料科技有限公司 | A kind of compound cerium zirconium sosoloid and preparation method thereof |
| CN105736093B (en) * | 2016-03-02 | 2018-04-10 | 吴振华 | A kind of polynary nanometer rare earth catalyst tail gas cleaner for motor-driven vehicle and its manufacture method |
| CN112573569B (en) * | 2020-12-23 | 2021-09-03 | 江门市科恒实业股份有限公司 | Rare earth composite oxide with high heat resistance and preparation method thereof |
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