CN109939727A - SCR catalyst and preparation method and purposes containing cerium - Google Patents
SCR catalyst and preparation method and purposes containing cerium Download PDFInfo
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Abstract
The invention discloses a kind of SCR catalyst containing cerium and preparation methods and purposes.The SCR catalyst has micropore and composite mesoporous sheet-like morphology or honeycomb sheet-like morphology, and micropore accounts for the 15~30% of entire pore volume；Acid amount is 0.2~1mmol/g.Catalyst low-temperature denitration function admirable of the invention.
Description
Technical field
The present invention relates to a kind of SCR catalyst containing cerium and preparation method and purposes, especially one kind can remove it is motor-driven
The SCR catalyst and its preparation method and application of nitrogen oxides in tail gas.
Background technique
Nitrogen oxides (NO in automotive emissionx) content is very high, cause atmosphere pollution constantly to aggravate.Therefore, motor-driven
NO in tail gasxThe urgency of prevention and treatment is increasingly prominent.Selective catalytic reduction (SCR) can be used for NOxPrevention and treatment.In catalyst
Under the action of, utilize reducing agent (such as NH3, liquefied ammonia, urea etc.) come selectively with the NO in tail gasxReaction, and generate nontoxic
Free of contamination N2And H2O.SCR technology is to NO in tail gasxControl effect is very significant.
CN105032387A discloses a kind of low-temperature denitration catalyst, active component Cr2O3And V2O5, NiSO4To help
Agent, titanium dioxide are carrier.Cr and V has severe toxicity, and a large amount of industrial applications can cause to seriously endanger to human body with environment.
CN107899577A discloses a kind of no vanadium based denitration catalyst, passes through the compound oxidability for improving iron ion of iron-titanium
With the locomitivity of Lattice Oxygen, the acidic site of catalyst is enriched, to be conducive to the raising of high temperature denitration performance, but not
The low-temperature denitration performance of such catalyst is described.
CN103877986A discloses a kind of ferrotungsten composite oxides denitrating catalyst with piece flower-like structure, and piece is flower-shaped
Structure is made of multi-disc petal, such catalyst catalytic activity with higher and sulfur resistive and water intoxication ability.
CN104624199B discloses a kind of preparation method of Mn base rod shape microscopic appearance composite oxides low-temperature denitration catalyst, this is urged
Agent has good low-temperature denitration performance.It is de- that CN108439463A discloses a kind of nano bar-shape pattern CuTi composite oxides
The preparation method of denox catalyst, the pattern catalyst can effectively improve catalytic efficiency.CN105032398B discloses a kind of sheet
The V of pattern carrier2O5/ titanium dioxide low temperature NH3SCR catalyst has better denitration performance.
CN107715858A discloses a kind of preparation method of SCR catalyst of the high temperature resistant to sulfur containing cerium, by the catalysis containing cerium
Agent is in SCR reaction.Such catalyst has excellent NH3- SCR catalytic activity and sulfur resistive water repelling property, but in low temperature
Lower denitration effect is bad.CN109078631A discloses a kind of catalyst containing cerium of efficient cryogenic, can according to its test data
Know, for the denitration efficiency at 200 DEG C 20% or so, cryogenic effect is bad.
Summary of the invention
In view of this, it is an object of the present invention to provide a kind of SCR catalyst containing cerium, with laminated structure,
Acidic site is abundant, and has mesoporous/micro-pore composite structure.
It is another object of the present invention to provide a kind of preparation methods of SCR catalyst containing cerium, use no water body
It is preparation method, the catalyst with laminated structure, acidic site abundant and mesoporous/micro-pore composite structure can be obtained.
It is yet a further object of the present invention to provide a kind of purposes of SCR catalyst containing cerium, and denitration is imitated at low temperature
Rate is higher.The present invention adopts the following technical scheme that realization above-mentioned purpose.
On the one hand, the present invention provides a kind of SCR catalyst containing cerium, the SCR catalyst have micropore with it is composite mesoporous
Sheet-like morphology or honeycomb sheet-like morphology, micropore accounts for the 15~30% of entire pore volume；Acid amount is 0.2~1mmol/g；Wherein,
Micropore indicates that aperture is less than the hole of 2nm；The mesoporous hole for indicating aperture between 2~50nm.
On the other hand, the present invention provides a kind of preparation method of SCR catalyst containing cerium, comprising the following steps:
(1) urea is ground into solution with containing sugar substance；It is added and contains cerium salt, and continue to grind；Tungstates and activity is added
Auxiliary agent, and continue to grind；Then titanium dioxide is added, and continues to grind, obtains the first mixed liquor；
(2) by urea and heating stirring containing sugar substance at solution；It is added containing mantoquita or contains molysite, and continue heating stirring；
Then micro porous molecular sieve is added, and continues heating stirring, obtains the second mixed liquor；
(3) the first mixed liquor is added in the second mixed liquor and is uniformly mixed, heating reaction forms third mixed liquor, then
Calcination process obtains the SCR catalyst.
Preparation method according to the present invention, it is preferable that in step (1), the tungstates is ammonium tungstate, ammonium metatungstate or secondary
Ammonium tungstate；The coagent is selected from the salt that one of Zr, Co, La, Pr, Nd or Mo or multiple element are formed；The dioxy
Change titanium is nano-titanium dioxide；The sugar substance that contains is monosaccharide or disaccharides.
Preparation method according to the present invention, it is preferable that in step (1), urea and the weight ratio containing sugar substance are 1:1~5:
1；With CeO2Poidometer contains cerium salt, titanium dioxide and with WO3Weight ratio between the tungstates of poidometer be 15~22:50~
83:2~10；With the coagent of trivalent poidometer and with CeO2Poidometer containing the weight ratio between cerium salt be 1~
5:100。
Preparation method according to the present invention, it is preferable that in step (2), the sugar substance that contains is monosaccharide or disaccharides；It is described micro-
Porous molecular sieve is ZSM-5, SAPO-34 or SSZ-13.
Preparation method according to the present invention, it is preferable that be 5:1 between urea and weight ratio containing sugar substance in step (2)
~7:1；It is described in terms of oxide weight containing mantoquita or containing the weight ratio between molysite and the micro porous molecular sieve be 1~8:
100。
Preparation method according to the present invention, it is preferable that the micro porous molecular sieve with CeO2Poidometer contains between cerium salt
Weight ratio be 5~30:20~50.
Preparation method according to the present invention, it is preferable that (1) by urea with containing sugar substance grinding rate be 1000~
4000rpm and temperature are to be ground into solution at 70~100 DEG C；Be added contain cerium salt, and grinding rate be 1000~4000rpm and
Temperature is to continue 0.2~3h of grinding at 70~100 DEG C；Be added tungstates and coagent, and grinding rate be 1000~
4000rpm and temperature are to continue 0.2~3h of grinding at 70~100 DEG C；Then titanium dioxide is added, and is 1000 in grinding rate
~4000rpm and temperature are to continue 1~5h of grinding at 70~100 DEG C, obtain the first mixed liquor；
It (2) with low whipping speed containing sugar substance is 1000~2500rpm by urea and temperature is that heating is stirred at 70~100 DEG C
Mix solution；Be added containing mantoquita or contain molysite, and low whipping speed be 1000~2500rpm and temperature be at 70~100 DEG C after
Continuous 0.5~5h of heating stirring；Then be added micro porous molecular sieve, and low whipping speed be 1000~2500rpm and temperature be 70~
Continue 3~15h of heating stirring at 100 DEG C, obtains the second mixed liquor；
(3) the first mixed liquor is added in the second mixed liquor, and low whipping speed is to mix under 1000~2500rpm
It is even, 110~170 DEG C are then heated to, 1~5h is reacted, cools down 10~15h later, forms third mixed liquor, 500~700 DEG C of roastings
1~5h of processing is burnt, the SCR catalyst is obtained.
In another aspect, the present invention also provides a kind of SCR catalysts that above-mentioned preparation method is prepared.
Another aspect, the present invention also provides a kind of purposes of above-mentioned catalyst in motor-vehicle tail-gas denitration, catalyst exists
150 DEG C of denitration efficiency is 20% or more, in 200 DEG C of denitration efficiencies 60% or more.
SCR catalyst of the invention is prepared under non-aqueous solution environment.Pass through the ratio tune containing sugar substance, urea and salt
Control, can obtain the catalyst of sheet-like morphology.Preferred technical solution according to the present invention, by containing sugar substance, urea and salt
The regulation of ratio and cocatalyst component, can obtain acidic site micropore abundant and composite mesoporous sheet-like morphology containing cerium
Catalyst.SCR catalyst of the invention is used in the denitrification process of motor-vehicle tail-gas, can effectively be removed in motor-vehicle tail-gas
Nitrogen oxides, the denitration efficiency of especially nitrogen oxides at low temperatures greatly improves.
Having containing cerium catalyst for micropore of the invention and composite mesoporous sheet-like morphology or honeycomb sheet-like morphology is excellent
Denitration performance helps to improve the denitration performance under its low temperature (150~300 DEG C), especially in 150~200 DEG C, denitration
It can greatly improve；At 150 DEG C denitration efficiency can improve to 20% or more, had reached 60%~80% at 200 DEG C.
Detailed description of the invention
Fig. 1 is the shape appearance figure of catalyst of the honeycomb sheet containing cerium of embodiment 1.
Fig. 2 a is the mesoporous distribution map of catalyst of the honeycomb sheet containing cerium of embodiment 1.
Fig. 2 b is the micropore distribution map of catalyst of the honeycomb sheet containing cerium of embodiment 1.
Fig. 3 is the shape appearance figure of catalyst of the sheet containing cerium of embodiment 3.
Fig. 4 is the shape appearance figure of the catalyst containing cerium of comparative example 1.
Fig. 5 is the denitration performance of the catalyst synthesized in embodiment 1, embodiment 2, embodiment 3 and comparative example 1.
Specific embodiment
The present invention is further illustrated combined with specific embodiments below, but protection scope of the present invention is not limited to
This.
The catalytic active center of solid catalyst is acid centre, i.e., catalyst surface can provide proton (B acid) or
Receive electronics to the acidic site of (L acid), mainly by the type (B acid and L acid) in acid site, quantity (also known as acidity, acid concentration or acid
Amount) and intensity (also known as acid strong, that is, provide proton or connect nucleophobic ability) three in terms of describe." acid amount " refers to unit weight
Measure mM number of acidic site on catalyst, unit mmol/g.
In the present invention, micropore indicates that aperture is less than the hole of 2nm；The mesoporous hole for indicating aperture between 2~50nm.
In the present invention, honeycomb sheet-like morphology be the random cross arrangement of laminated structure together, the surface of laminated structure
It is uneven, similar honeycomb.Together for the random cross arrangement of laminated structure, the surface of laminated structure is with respect to bee for sheet-like morphology
The laminated structure surface of nest sheet-like morphology is relatively smooth.
Preparation method of the invention includes the following steps: the preparation step of (1) first mixed liquor；(2) second mixed liquors
Preparation step；(3) forming step of SCR catalyst.
<preparation step of the first mixed liquor>
The preparation step of first mixed liquor of the invention are as follows: urea is ground into solution with containing sugar substance；It is added and contains cerium salt, and
Continue to grind；Tungstates and coagent is added, and continues to grind；Then titanium dioxide is added, and continues to grind, obtains first
Mixed liquor.It is a discovery of the invention that the addition sequence of above-mentioned raw materials is for the catalyst of sheet-like morphology and the quantity of increase acidic site
Important.Grinding is different from stirring, and the mode of grinding is conducive to improve catalyst morphology.Can using equipment known in the art into
Row grinding.
In the present invention, the tungstates can be ammonium tungstate, ammonium metatungstate or ammonium paratungstate；Preferably ammonium paratungstate.
The salt that the coagent can be formed selected from one of Zr, Co, La, Pr, Nd, Mo or multiple element；Preferably La salt, Pr
Salt, Nd salt；More preferably La salt.Salt of the invention can be nitrate, carbonate, hydrochloride or sulfate etc..Of the invention
The example of coagent includes but is not limited to lanthanum nitrate, praseodymium nitrate, neodymium nitrate, lanthanum carbonate, praseodymium carbonate, neodymium carbonate, lanthanum chloride, chlorine
Change praseodymium, neodymium chloride etc.；Preferably lanthanum nitrate, neodymium nitrate or lanthanum carbonate.The titanium dioxide can be nano-titanium dioxide；Its grain
Diameter can be 10~90nm.The sugar substance that contains can be monosaccharide or disaccharides；Preferably monosaccharide.Example containing sugar substance include but
It is not limited to glucose, fructose, sucrose etc., preferably glucose.Micropore and composite mesoporous knot are help to obtain using above-mentioned raw materials
Structure.Wherein, it when cerium salt is carbonate, is more likely to form the smooth sheet-like morphology in surface.Test proof, sheet-like morphology structure
For catalyst under conditions of guaranteeing that low-temperature denitration works well, high temperature denitration effect is better than the catalyst of honeycomb sheet-like morphology.
In the present invention, urea and the weight ratio containing sugar substance can be 1:1~5:1；Preferably 1:1~3:1, more preferably
For 2:1~3:1, which is more advantageous to the generation of micropore.
In the present invention, with CeO2Poidometer meter contains cerium salt, titanium dioxide and with WO3Between the tungstates of poidometer meter
Weight ratio be 15~22:50~83:2~10；Preferably 16~22:55~70:3~9；More preferably 18~22:55~65:
5~8.With the coagent of trivalent poidometer and with CeO2Poidometer is 1~5 containing the weight ratio between cerium salt:
100；Preferably 1.5~3.5:100；More preferably 1.5~2.5:100.The acid amount of catalyst can be made higher in this way.
In the present invention, urea is ground into solution with containing sugar substance, until forming uniform abrasive solution.Grinding rate
For 1000~4000rpm, preferably 1100~3000rpm, more preferably 1200~1800rpm.Grinding temperature is 70~100
DEG C, preferably 75~90 DEG C preferably 80~85 DEG C.Sheet-like morphology or honeycomb sheet-like morphology are advantageously formed in this way.
In the present invention, it is added into abrasive solution and contains cerium salt, continue to grind, form mixture containing cerium salt.Grinding rate
For 1000~4000rpm, preferably 1100~3000rpm, more preferably 1200~1800rpm.Grinding temperature is 70~100
DEG C, preferably 75~90 DEG C, more preferably 80~85 DEG C.The time for continuing grinding is 0.2~3h；Preferably 0.3~2h；It is more excellent
It is selected as 0.5~1h.Sheet-like morphology or honeycomb sheet-like morphology are advantageously formed in this way.
In the present invention, tungstates and coagent is added to mixture containing cerium salt, continues to grind, formed mixed containing tungstates
Close object.Grinding rate is 1000~4000rpm, preferably 1100~3000rpm, more preferably 1200~1800rpm.Grinding temperature
Degree is 70~100 DEG C, preferably 75~90 DEG C, more preferably 80~85 DEG C.The time for continuing grinding is 0.2~3h；Preferably
0.3~2h；More preferably 0.5~1h.Sheet-like morphology or honeycomb sheet-like morphology are advantageously formed in this way.
In the present invention, titanium dioxide is added to mixture containing tungstates, continues to grind, form the first mixed liquor.Grinding
Speed is 1000~4000rpm, preferably 1100~3000rpm, more preferably 1200~1800rpm.Grinding temperature be 70~
100 DEG C, preferably 75~90 DEG C, more preferably 80~85 DEG C.The time for continuing grinding is 0.2~3h；Preferably 0.3~2h；
More preferably 0.5~1h.Sheet-like morphology or honeycomb sheet-like morphology are advantageously formed in this way.
<preparation step of the second mixed liquor>
The preparation step of second mixed liquor of the invention are as follows: by urea and heating stirring containing sugar substance at solution；Cupric is added
Salt contains molysite, and continues heating stirring；Then micro porous molecular sieve is added, and continues heating stirring, obtains the second mixed liquor.
It in the present invention, can be monosaccharide or disaccharides containing sugar substance；Preferably monosaccharide.Example containing sugar substance includes but not
It is limited to glucose, fructose, sucrose etc., preferably glucose.Micro porous molecular sieve can be ZSM-5, SAPO-34 or SSZ-13.It is excellent
Select ZSM-5 or SSZ-13.
It in the present invention, is 3:1~8:1, preferably 5:1~7:1 between urea and weight ratio containing sugar substance；More preferably
For 6:1~6.5:1.In terms of oxide weight containing mantoquita or containing the weight ratio between molysite and micro porous molecular sieve be 1~8:
100；Preferably 2~6:100；More preferably 2~5:100.The acid amount of catalyst can be improved in this way, while improving denitration effect
Fruit.
In the present invention, micro porous molecular sieve with CeO2Poidometer containing the weight ratio between cerium salt be 5~30:20~
50；Preferably 20~25:20~35；More preferably 20~25:20~30.Be conducive to improve the micropore accounting of catalyst in this way.
In the present invention, by urea and heating stirring containing sugar substance at solution, until forming uniform solution.Mixing speed is
1000~2500rpm, preferably 1100~2000rpm, more preferably 1200~1500rpm.Whipping temp is 70~100 DEG C,
Preferably 75~90 DEG C, more preferably 80~85 DEG C.Sheet-like morphology or honeycomb sheet-like morphology are advantageously formed in this way.
In the present invention, it is added into solution containing mantoquita or contains molysite, form dispersion liquid.Mixing speed be 1000~
2500rpm, preferably 1100~2000rpm, more preferably 1200~1500rpm.Whipping temp is 70~100 DEG C, preferably
75~90 DEG C, more preferably 80~85 DEG C.Mixing time is 0.5~5h；Preferably 0.6~3h；More preferably 1~2h.In this way
Advantageously form sheet-like morphology or honeycomb sheet-like morphology.
In the present invention, micro porous molecular sieve is added into dispersion liquid, stirs to form the second mixed liquor.Mixing speed is
1000~2500rpm, preferably 1100~2000rpm, more preferably 1200~1500rpm.Whipping temp is 70~100 DEG C,
Preferably 75~90 DEG C, more preferably 80~85 DEG C.Mixing time is 3~15h；Preferably 3~10h；More preferably 4~8h.
Sheet-like morphology or honeycomb sheet-like morphology are advantageously formed in this way.
<SCR catalyst forming step>
SCR catalyst forming step of the present invention are as follows: the first mixed liquor is added in the second mixed liquor and is uniformly mixed, is heated
Reaction forms third mixed liquor, and then calcination process, obtains the SCR catalyst.The second mixed liquor is added in first mixed liquor
In, and low whipping speed is to mix under 1000~2500rpm, preferably 1100~2000rpm, more preferably 1200~1500rpm
It closes uniformly, then heats to 110~170 DEG C, preferably 115~160 DEG C, be more preferably 1~5h of reaction at 120~150 DEG C, be excellent
It is selected as 2~5h, more preferably 2~3h, 5~25h, preferably 10~20h, more preferably 10~15h is cooled down later, forms third
Mixed liquor；500~700 DEG C, preferably 550~650 DEG C, more preferably 1~5h of calcination process at 550~600 DEG C, preferably
2~5h, more preferably 2~3h, obtain the SCR catalyst.
According to embodiment of the present invention, it comprises the following specific steps that:
(1) by urea with containing sugar substance grinding rate be 1000~4000rpm under abrasive solution, by adjusting grinding speed
Degree control solution temperature be 70~100 DEG C, be added containing cerium salt continue 0.5~1h of grinding until its be uniformly dispersed, tungsten is then added
Hydrochlorate and coagent grind 0.5~1h until it is uniformly dispersed, and holding grinding revolving speed is constant, continuously adds titanium dioxide grinding
1~2h obtains the first mixed liquor；
(2) urea is heated to 70~100 DEG C with containing sugar substance in proportion, control mixing speed is 1000~2500rpm
It stirs into solution, be added containing mantoquita or be dispersed with stirring 1~2h at micro porous molecular sieve is then added, continues heating stirring containing molysite
5~7h of dispersion obtains the second mixed liquor；
(3) it keeps 70~100 DEG C of solution temperature and 1000~2500rpm of mixing speed constant, the first mixed solution is added
Entering in the second mixed liquor, raising mixeding liquid temperature is to 110~170 DEG C, 2~3h of stirring, room temperature cooling 10~for 24 hours, 500~650
2~4h is roasted at DEG C obtains the SCR catalyst.
<catalyst and purposes>
It is micropore and composite mesoporous structure that the present invention, which provides the SCR catalyst that above-mentioned preparation method obtains,；The SCR is urged
The acid amount of agent is 0.2~1mmol/g；The SCR catalyst has sheet-like morphology or honeycomb sheet-like morphology.
The present invention provides a kind of SCR catalyst containing cerium, has micropore and composite mesoporous sheet-like morphology or honeycomb sheet
Pattern, micropore account for the 15~30% of entire pore volume；Acid amount is 0.2~1mmol/g.Micropore indicates that aperture is less than the hole of 2nm；It is situated between
Hole indicates hole of the aperture between 2~50nm.It is preferably 17~28% that micropore, which accounts for entire pore volume, and more preferably 19~25%.
Be conducive to improve the low-temperature denitration effect of catalyst in this way.Acid amount is preferably 0.7~1mmol/g, more preferably 0.9~1mmol/
g.Be conducive to improve the low-temperature denitration effect of catalyst in this way.Catalyst of the invention can be prepared using the above method,
Details are seen above, and which is not described herein again.
SCR catalyst of the invention is used for motor-vehicle tail-gas denitration.The catalyst 150 DEG C denitration efficiency 20% with
On, in 200 DEG C of denitration efficiencies 60% or more.The catalyst is mainly used for the field diesel vehicle SCR.Above-mentioned denitration efficiency can
It is measured with simulating in exhaust gas from diesel vehicle gas volume than forming: 100~1500ppm NO, 100~1500ppm NH3, 6~
15vol%O2, 0~20vol%H2O, 4~8vol%CO2, 200~1000ppm CO, 30~90ppm C3H6(C3), N2It is flat
Weigh gas.Air speed (GHSV) is 30000~300000m/h.NH3/ NO volume ratio is 0.5~1.5, and gas detecting system is flue gas point
Analyzer.
Test and the characterizing method of embodiment and comparative example is described below:
Specific surface area test: testing specific surface area of catalyst using Mike's 2020HD88 ratio surface area instrument, tests
When degassing temperature be 105 DEG C, degassing time 2h.In triplicate, it is averaged.
Pattern test: using 500 field emission scanning electron microscope of Zeiss, Germany Sigma to catalyst microscopic appearance into
Row test.Sample test front surface sprays one layer of thin platinum to improve the electric conductivity of sample surfaces.
Acid measures examination: being carried out using ammonia adsorption desorption performance of health tower ASAP 292011 chemical adsorption instrument in the U.S. to catalyst
Test is desorbed peak area according to ammonia and calculates its acid amount.
Embodiment 1
(1) 36g glucose and 72g urea are ground under the conditions of grinding rate is 1500rpm to form solution, solution temperature
Degree is 80 DEG C.The solution is added in 7.2082g cerous nitrate, continues to grind 0.5h；Then be added 1.6085g ammonium paratungstate and
0.2051g lanthanum nitrate, and continue to grind 0.5h and be uniformly dispersed to them.It keeps grinding revolving speed constant, continuously adds 10g titanium dioxide
Titanium, grinding 1.5h obtain the first mixed liquor.
It (2) is heating stirring under 1100rpm to form solution, solution by 36g glucose and 216g urea low whipping speed
Temperature is 80 DEG C.Above-mentioned solution is added in 0.3448g copper nitrate, continues to stir 1h；Then 2.8570g SSZ-13 is added, continues
Stirring 6h obtains the second mixed liquor.SSZ-13 is that specific surface is greater than 400m2The molecular sieve of/g.
(3) the first mixed liquor is added in the second mixed liquor, low whipping speed is to react 0.5h under 1200rpm；Then it rises
Temperature reacts 2h to 130 DEG C；10h is cooled down later.Then 3h is roasted at 550 DEG C, obtains SCR catalyst.
The pattern of SCR catalyst is referring to Fig. 1, micropore and composite mesoporous structure a and Fig. 2 b referring to fig. 2, physical and chemical performance
Referring to table 1, catalytic activity is referring to Fig. 5.
Embodiment 2
(1) 36g glucose and 90g urea are ground under the conditions of grinding rate is 1500rpm to form solution, solution temperature
Degree is 80 DEG C.The solution is added in 7.2082g cerous nitrate, continues to grind 0.5h；Then be added 1.6085g ammonium paratungstate and
0.1860g neodymium nitrate, and continue to grind 0.5h and be uniformly dispersed to them.It keeps grinding revolving speed constant, continuously adds 10g titanium dioxide
Titanium, grinding 1.5h obtain the first mixed liquor.
It (2) is heating stirring under 1100rpm to form solution, solution by 36g glucose and 234g urea low whipping speed
Temperature is 80 DEG C.Above-mentioned solution is added in 0.3448g copper nitrate, continues to stir 1h；Then 2.8570g ZSM-5 is added, continues
Stirring 6h obtains the second mixed liquor.ZSM-5 is that specific surface is greater than 400m2The molecular sieve of/g.
(3) the first mixed liquor is added in the second mixed liquor, low whipping speed is to react 0.5h under 1200rpm；Then it rises
Temperature reacts 2h to 130 DEG C；12h is cooled down later.Then 3h is roasted at 550 DEG C, obtains SCR catalyst.
The physical and chemical performance of the SCR catalyst is shown in Table 1, and reactivity is shown in Fig. 5.
Embodiment 3
(1) 36g glucose and 72g urea are ground under the conditions of grinding rate is 1500rpm to form solution, solution temperature
Degree is 80 DEG C.The solution is added in 3.8213g cerous carbonate, continues to grind 1h；Then be added 1.6085g ammonium paratungstate and
0.0803g lanthanum carbonate, and continue to grind 1h and be uniformly dispersed to them.It keeps grinding revolving speed constant, continuously adds 10g titanium dioxide
Titanium, grinding 2h obtain the first mixed liquor.
It (2) is heating stirring under 1100rpm to form solution, solution by 36g glucose and 216g urea low whipping speed
Temperature is 80 DEG C.Above-mentioned solution is added in 0.3448g copper nitrate, continues to stir 1h；Then 2.8570g SSZ-13 is added, continues
Stirring 6h obtains the second mixed liquor.SSZ-13 is that specific surface is greater than 400m2The molecular sieve of/g.
(3) the first mixed liquor is added in the second mixed liquor, low whipping speed is to react 0.5h under 1200rpm；Then it rises
Temperature reacts 2h to 130 DEG C；11h is cooled down later.Then 3h is roasted at 550 DEG C, obtains SCR catalyst.
The pattern of SCR catalyst referring to Fig. 1, physical and chemical performance referring to table 1, micropore and composite mesoporous structure referring to fig. 2,
Catalytic activity is referring to Fig. 5.
Comparative example 1
(1) 7.2082g cerous nitrate is added in 80 DEG C of water of 50mL and is dispersed with stirring 0.5h, 1.6085g para-tungstic acid is then added
Ammonium, 0.2051g lanthanum nitrate continue heating stirring 0.5h and are uniformly dispersed to it, add 10g titanium dioxide stirring 1.5h and obtain the
One mixed liquor.
(2) 0.3448g copper nitrate is added in 80 DEG C of 100mL water and is dispersed with stirring 1h, 2.8570g SSZ-13 is then added,
Persistently stirring 6h obtains the second mixed liquor.
(3) the first mixed solution is added in the second mixed liquor and is stirred to react 0.5h, then heated to 130 DEG C and be stirred to react
2h is cooled to room temperature later, is filtered, washing, is roasted 3h at 550 DEG C, is obtained the SCR catalyst.
The pattern of synthesized SCR catalyst is shown in that Fig. 4, physical and chemical performance are shown in Table 1, and catalytic activity is shown in Fig. 5.
Embodiment 1, embodiment 2, embodiment 3 and the catalyst physical chemical property in comparative example 1 are as shown in table 1 below:
Table 1
As seen from table, under non-aqueous solution environment, regulated and controled by the ratio of sugar, urea and salt, can obtain micropore with
The catalyst containing cerium of composite mesoporous honeycomb sheet-like morphology or sheet-like morphology.Preparation method of the invention can greatly improve micro-
The ratio in hole.In addition, the specific surface area of catalyst in the present invention is big, acidic site is abundant, can achieve 0.7~1mmol/g.
Catalyst is subjected to SCR denitration performance test.Reaction gas group becomes (volume ratio): 500ppm NO, 500ppm
NH3, 12vol%O2, 10vol%H2O, 8vol%CO2, 800ppm CO, 80ppm C3H6(C3), N2For Balance Air.Air speed
It (GHSV) is 250000m/h-1.Gas detecting system is flue gas analyzer.Catalyst is 50 mesh particles.Embodiment 1, embodiment
2, the catalyst performance in embodiment 3 and comparative example 1 is referring to Fig. 5.
As shown in Figure 5, catalyst of the invention have excellent denitration performance, low temperature (150~300 DEG C) denitration performance,
Denitration performance especially in 150~200 DEG C is improved.Existing catalyst denitration conversion ratio at 150 DEG C is 10% or so,
Denitration conversion ratio at 200 DEG C is 20% (referring to CN109078631A).The denitration effect of catalyst of the invention at 150 DEG C
Rate is improved to 20% or more, reaches 60% or more in 200 DEG C of denitration efficiencies.
Present invention is not limited to the embodiments described above, without departing from the essence of the present invention, this field skill
Any deformation, improvement, the replacement that art personnel are contemplated that each fall within the scope of the present invention.
Claims (10)
1. a kind of SCR catalyst containing cerium, which is characterized in that the SCR catalyst has micropore and composite mesoporous sheet-shaped
Looks or honeycomb sheet-like morphology, micropore account for the 15~30% of entire pore volume；Acid amount is 0.2~1mmol/g；Wherein, micropore indicates
Aperture is less than the hole of 2nm；The mesoporous hole for indicating aperture between 2~50nm.
2. a kind of preparation method of the SCR catalyst containing cerium, which comprises the following steps:
(1) urea is ground into solution with containing sugar substance；It is added and contains cerium salt, and continue to grind；Tungstates and coagent is added,
And continue to grind；Then titanium dioxide is added, and continues to grind, obtains the first mixed liquor；
(2) by urea and heating stirring containing sugar substance at solution；It is added containing mantoquita or contains molysite, and continue heating stirring；Then
Micro porous molecular sieve is added, and continues heating stirring, obtains the second mixed liquor；
(3) the first mixed liquor is added in the second mixed liquor and is uniformly mixed, heating reaction forms third mixed liquor, then roasts
Processing, obtains the SCR catalyst.
3. preparation method according to claim 2, which is characterized in that in step (1), the tungstates is ammonium tungstate, partially
Ammonium tungstate or ammonium paratungstate；The coagent is selected from one of Zr, Co, La, P r salt, Nd or Mo or multiple element is formed
Salt；The titanium dioxide is nano-titanium dioxide；The sugar substance that contains is monosaccharide or disaccharides.
4. preparation method according to claim 2, which is characterized in that in step (1), urea and the weight ratio containing sugar substance
For 1:1~5:1；With CeO2Poidometer contains cerium salt, titanium dioxide and with WO3Weight ratio between the tungstates of poidometer is 15
~22:50~83:2~10；With the coagent of trivalent poidometer and with CeO2Poidometer containing the weight between cerium salt
Amount is than being 1~5:100.
5. preparation method according to claim 2, which is characterized in that in step (2), the sugar substance that contains is monosaccharide or two
Sugar；The micro porous molecular sieve is ZSM-5, SAPO-34 or SSZ-13.
6. preparation method according to claim 2, which is characterized in that in step (2), urea and the weight ratio containing sugar substance
Between be 3:1~8:1；It is described in terms of oxide weight containing mantoquita or containing the weight ratio between molysite and the micro porous molecular sieve
For 1~8:100.
7. preparation method according to claim 2, which is characterized in that the micro porous molecular sieve with CeO2Poidometer contains
Weight ratio between cerium salt is 5~30:20~50.
8. according to the described in any item preparation methods of claim 2~7, it is characterised in that:
(1) by urea with containing sugar substance be ground into the case where grinding rate is 1000~4000rpm and temperature is 70~100 DEG C it is molten
Liquid；It is added and contains cerium salt, and continue 0.2~3h of grinding in the case where grinding rate is 1000~4000rpm and temperature is 70~100 DEG C；
Tungstates and coagent is added, and continues to grind in the case where grinding rate is 1000~4000rpm and temperature is 70~100 DEG C
0.2~3h；Then titanium dioxide is added, and continues to grind in the case where grinding rate is 1000~4000rpm and temperature is 70~100 DEG C
1~5h is ground, the first mixed liquor is obtained；
(2) by urea and low whipping speed containing sugar substance be 1000~2500rpm and temperature be at 70~100 DEG C heating stirring at
Solution；It is added containing mantoquita or contains molysite, and low whipping speed is 1000~2500rpm and temperature is to continue to add at 70~100 DEG C
0.5~5h of thermal agitation；Then micro porous molecular sieve is added, and low whipping speed is 1000~2500rpm and temperature is 70~100 DEG C
Lower continuation 3~15h of heating stirring, obtains the second mixed liquor；
(3) the first mixed liquor is added in the second mixed liquor, and low whipping speed is to be uniformly mixed under 1000~2500rpm, so
After be warming up to 110~170 DEG C, react 1~5h, cool down 10~15h later, form third mixed liquor, at 500~700 DEG C of roastings
1~5h is managed, the SCR catalyst is obtained.
9. the SCR catalyst being prepared according to the described in any item preparation methods of claim 2~8.
10. according to claim 1 or purposes of the SCR catalyst described in 9 in motor-vehicle tail-gas denitration, which is characterized in that should
Catalyst in 150 DEG C of denitration efficiency 20% or more, in 200 DEG C of denitration efficiencies 60% or more.
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