CN103977842B - A kind of Vehicle Exhaust Gas Cleaning Catalysts painting method - Google Patents
A kind of Vehicle Exhaust Gas Cleaning Catalysts painting method Download PDFInfo
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Abstract
The invention provides a kind of Vehicle Exhaust Gas Cleaning Catalysts painting method, comprise that step (1) support pretreatment, (2) carrier sensitization, (3) are support-activated, (4) electroless deposition, the present invention breaches traditional infusion process, the precipitation method, the technical bottlenecks such as vacuum coat method, successfully achieve the uniform load of noble metal catalyst in wall-flow type honeycomb ceramic carrier micropore and on through type honeycomb ceramic carrier coating, and noble metal catalyst particle diameter prepared by the present invention is 50 ~ 100nm, there is the performance of nano particle, its specific area is large, catalytic, reactivity improves a lot than large scale catalyst under equal conditions, in addition this method uses precious metal salt, price is relatively low, therefore significantly noble metal dosage can be reduced, and without the need to techniques such as high-temperature calcinations, simple to operate, easy realization, carrier is applied widely.
Description
Technical field
The invention belongs to air contaminant treatment and environment protection catalytic Material Field, be specifically related to a kind of Vehicle Exhaust Gas Cleaning Catalysts painting method.
Background technology
Along with the fast development of economy, the demand of people to motor vehicles grows with each passing day, output and the recoverable amount of domestic motor vehicles sharply increase, tail gas pollution of motor-driven vehicle problem is also more and more serious, interrelated data shows: the big cities such as Beijing, Shanghai, Guangzhou, motor-vehicle tail-gas has become the main source of atmosphere pollution.Particularly diesel engine becomes the major impetus of motor vehicle just gradually because of features such as its thermal efficiency are high, fuel economy is good, the life-span is long.But containing a large amount of nitrogen oxide (NO in diesel engine vent gas
x) and particle (PM), the especially discharge of particle, limit it and apply.China's central and east most area in 2013 occurs continuing blind haze weather, especially Beijing, capital haze reaches 60 days, urge the proposition of Cheng Liao state V vehicle exhaust standard and the enforcement in Beijing area, add granular material discharged restriction in this standard, and add the inspection requirements of crucial emission control parts (catalytic converter).Therefore strictly control diesel particulate discharge and become the task of top priority.
Automobile pollution control measure are divided into emission controls by improving combustion and machine to control two class technology outward, and wherein catalytic converter is one of outer exhaust purifying method of the most effective machine.For diesel engine, catalytic converter can adsorb and retains soot particulate, some particles, CO, THC etc. in tail gas is rapidly converted into CO under the effect of catalyst simultaneously
2, H
2o, N
2deng innocuous substance.Cleaning catalyst as one of the Main Means that cleaning of off-gas pollutes is subject to the extensive concern of researcher in recent years.Wherein noble metal catalyst because its good low temperature light-off performance, catalytic activity are high, the advantage such as good stability, life-span be long, it occupies extremely important status in motor-driven vehicle gas disposal.Noble metal at present for purifying vehicle exhaust mainly contains rhodium (Rh), platinum (Pt), palladium (Pd), and Rh has promotion NOx and is optionally reduced to N
2, also showed good sulfur poisoning resistance; Pt has good Catalytic Combustion Effect to soot particulate in diesel engine vent gas; Pt, Pd oxidation to CO, HC has very high activity.But Precious Metals Resources is in short supply, expensive limits its application in tail gas catalyzed, and therefore people reduce noble metal dosage at finding method, keep the method for its catalytic activity always simultaneously.
It is the removal efficiency improving soot particulate (soot) in diesel car tail gas refining field, general employing porous material is as carrier, the research of present stage to honeycomb ceramic filter concentrates on prepares forming method, pore structure parameter and regeneration techniques, and relates to the coating few people of catalyst in micropore on its filtering surface.
The method that current noble-metal coated is commonly used has:
1) infusion process, carrier is immersed in the solution containing one or more noble metal precursor things, liquid (noble metal) is made to penetrate into support voids inside by the capillary pressure in carrier duct, the required catalyst can made after the steps such as the carrier drying after dipping, Muffle furnace roasting.Can be divided into excessive infusion process and equi-volume impregnating again, the volume of excessive infusion process and dipping solution is greater than carrier bulk, and the method noble-metal-supported evenly but can not control noble-metal-supported amount, is not many times that load capacity is the bigger the better.Incipient impregnation and carrier bulk consistent with maceration extract volume, maceration extract can just inside fully enter openings, although can control noble-metal-supported amount eaily, its decentralization is very poor, and Granular composite is uneven.The publication of this technique is used to have CN1239017A, CN1055302A, CN1191127C etc.
2) vacuum covering technology, immerse slurry by honeycomb ceramic carrier one end, aspirate by force at the other end, after reaching a certain height, carrier rotates 180 °, and using the same method applies the other end.Vacuum covering technique ensure that carrier duct can apply spreading mass, and eyelet can not occur all to fill in, but its structure and driver complexity, add the cost of Catalyst Production, and be difficult in micropore, realize evenly coating.The publication of this technique is used to have CN203370699U, CN103386391A etc.
3) precipitation method, refer to and add in agitator by aqueous metal salt, carrier is put into solution and floods, after add precipitating reagent, active component is precipitated at carrier surface, generate solid sediment.After having precipitated, by the finished catalyst with sedimentary carrier washing, filtration, drying, roasting.The method is simple to operate, and feasibility is high, but the uncontrollable precipitant concentration of catalyst prepared by the precipitation method is on the impact of shaping particles, and the position shaped granule radius therefore had is comparatively large, uneven.The publication of this technique is used to have CN1927459B etc.
In sum, existing noble-metal coated method cost is high, complex procedures, and is difficult to use in the coating of honeycomb ceramic filter micropore inner catalyst.
Summary of the invention
Shortcoming of the prior art in view of the above, the invention provides a kind of Vehicle Exhaust Gas Cleaning Catalysts coating new method, by adopting the synthetic route of bottom-up in aqueous phase, growth has the noble metal catalyst of Nano-cluster configuration.
A kind of Vehicle Exhaust Gas Cleaning Catalysts painting method, comprises the steps:
(1) support pretreatment
Described carrier is honeycomb ceramic filter or through type ceramic honey comb, is soaked by described carrier in nitric acid, cleans post-drying;
(2) carrier sensitization
Immersed in sensitizing solution by the carrier handled well in step (1), the solvent of described sensitizing solution is deionized water and CH
3oH, solute is SnCl
2and C
2hF
3o
2;
(3) support-activated
By the carrier through sensitization in step (2), take out and first use washed with methanol, then use pure water rinsing, immerse in activating solution afterwards; Described activating solution is by AgNO
3be dissolved in wiring solution-forming in pure water, then carry out titration with ammoniacal liquor until brown oxidation silver precipitation disappears, namely obtain activating solution;
(4) electroless deposition
Preparation precious metal salt solution: precious metal salt solution is the aqueous solution containing one or more soluble-salts in platinum, palladium, rhodium;
Configuration plating solution: described plating solution is that described precious metal salt solution is added complexing agent, and described complexing agent is ammoniacal liquor; Ammoniacal liquor as complexing agent, both Absorbable organic halogens pH value in the plating solution, again can with precious metal ion complexing, therefore add suitable ammoniacal liquor, can bath stability be kept, can reaction rate be accelerated again.
Deposition reaction: by carrier activated in step (3), takes out and first uses washed with methanol, then use pure water rinsing, immerses in plating solution afterwards; Immerse in plating solution to start to react from carrier and constantly add reducing agent to reaction terminal procedure, described reducing agent is the one in hydrazine hydrate, hypophosphites, phosphite, borine, trimethylamine, formaldehyde.
As preferred embodiment, described step (1) support pretreatment is further: carrier is honeycomb ceramic filter or through type ceramic honey comb, the nitric acid dousing carrier with 5 ~ 30% 24 hours, cleans with pure water, dries 10 hours at 90 ~ 120 DEG C.
As preferred embodiment, described step (2) carrier sensitization is further: the carrier handled well in step (1) is put into sensitizing solution, and stop 30 ~ 90min, the solvent of described sensitizing solution is deionized water and the CH of volume ratio 1:1
3oH, solute is SnCl
2and C
2hF
3o
2, SnCl
2concentration be 17 ~ 27mmol/L, C
2hF
3o
2concentration be 60 ~ 80mmol/L.
As preferred embodiment, described step (3) is support-activated is further: by the carrier through sensitization in step (2), takes out and first uses washed with methanol, use pure water rinsing again, immerse afterwards in activating solution, stop 10 ~ 30min, described activating solution is by AgNO
3be dissolved in pure water the solution being made into 30 ~ 40mmol/L, then carry out titration until brown oxidation silver precipitation disappears with the ammoniacal liquor of 37%, namely obtain activating solution.
As preferred embodiment, in described step (4), preparation precious metal salt solution is further:
(4.1) prepare precious metal salt solution, described precious metal salt solution solute is one or more soluble-salts containing platinum, palladium, rhodium, and solvent is pure water, and concentration is 0.1 ~ 10mmol/L;
As preferred embodiment, comprise before carrier immerses plating solution in described step (4):
(4.2) prepare surfactant solution, described surfactant solution solute is neopelex, and solvent is pure water, and concentration is 0.01 ~ 0.3mol/L; Described surfactant adds in plating solution as stabilizing agent, and stabilizing agent is conducive to bath stability, and can reduce reaction stress.
As preferred embodiment, in described step (4), preparation plating solution is further:
(4.3) prepare plating solution A, described plating solution A be by obtained precious metal salt solution and ammoniacal liquor by volume 1:1.5 ~ 1:4 mix and obtain.
As preferred embodiment, in described step (4), preparation plating solution also comprises:
(4.4) plating solution B is prepared, described plating solution B is described reductant solution or volume ratio is the described surfactant solution of 1:10 ~ 1:50 and the mixed liquor of reductant solution, and described reductant solution is selected from the following solution that concentration is 1-10mol/L: hydrazine hydrate aqueous solution, the hypophosphites aqueous solution, the phosphite aqueous solution, the borine aqueous solution, trimethylamine aqueous solution, formalin.
As preferred embodiment, in described step (4), deposition reaction is further:
(4.5) by carrier activated in step (3), take out and first use washed with methanol, use pure water rinsing again, immerse afterwards in plating solution A, afterwards plating solution B is added in plating solution A and obtain plating solution C, wherein the volume ratio of plating solution B and plating solution A is 1:1 ~ 1:3,20min ~ 150min is soaked in this solution at 40 ~ 70 DEG C, and upgrade once described plating solution C every 25 ~ 50min, in plating solution, add once described reductant solution in the middle of the interval of twice renewal plating solution, the described reductant solution added and the volume ratio of plating solution B are 1:2.
Become nonactive for making noble metal in plating solution to be all deposited before, this method adopts low concentration, repeatedly precipitates.
Because reducing agent is unstable in the plating solution, being easily hydrolyzed, therefore not adding reducing agent when preparing plating solution A simultaneously, but now with the current when carrying out electroless deposition, be first mixed with B plating solution, then join again in A plating solution when electroless deposition.
Because precious metal ion in plating solution is completely precipitable about half an hour, so primary sedimentation solution will be upgraded every 25 ~ 50min.Precious metal ion complete reaction in plating solution can be made like this, maximization of economic benefit.
As preferred embodiment, after electroless deposition, also comprise step:
(4.6), after electroless deposition, sample is clean by pure water rinsing, and 25% HNO
3soak 12 ~ 24h in solution, taking-up is clean by pure water rinsing, dries at 120 DEG C, i.e. obtained noble metal nano catalyst.
As mentioned above, the present invention has following beneficial effect: breach the technical bottlenecks such as traditional infusion process, the precipitation method, vacuum coat method, successfully achieve the uniform load of noble metal catalyst in wall-flow type honeycomb ceramic carrier micropore and on through type honeycomb ceramic carrier coating, and noble metal catalyst particle diameter prepared by the present invention is 50 ~ 100nm, there is the performance of nano particle, its specific area is large, and catalytic, reactivity improve a lot than large scale catalyst under equal conditions.In addition this technique uses precious metal salt, and price is relatively low, and plating solution also can repeatedly utilize, and therefore significantly can reduce noble metal dosage, and without the need to techniques such as high-temperature calcinations, simple to operate, easily realize.Carrier in the method is applied widely, except carrying out except the growth in situ of micropore noble metal catalyst for diesel particulate filter (DPF), also can be used for the load of through type honeycomb ceramic carrier active component in vehicle maintenance service.
Accompanying drawing explanation
Fig. 1 is the process chart of this method;
Fig. 2 is the single platinum catalyst scanning electron microscope (SEM) photograph in embodiment 1 with honeycomb ceramic filter prepared by carrier.
The single platinum nano catalyst EDX of Fig. 3 prepared by embodiment 1 schemes.
Fig. 4 is with single platinum catalyst scanning electron microscope (SEM) photograph that through type ceramic honey comb is prepared for carrier in embodiment 3.
The single platinum nano catalyst EDX of Fig. 5 prepared by embodiment 3 schemes.
The single platinum nano catalyst of Fig. 6 prepared by embodiment 4.
The single platinum nano catalyst EDX of Fig. 7 prepared by embodiment 4 schemes.
Detailed description of the invention
Below by way of specific instantiation, embodiments of the present invention are described, those skilled in the art the content disclosed by this description can understand other advantages of the present invention and effect easily.The present invention can also be implemented or be applied by detailed description of the invention different in addition, and the every details in this description also can based on different viewpoints and application, carries out various modification or change not deviating under spirit of the present invention.
Fig. 1 is the process chart using the inventive method to carry out Vehicle Exhaust Gas Cleaning Catalysts coating, and as shown in the figure, the noble metal catalyst painting method of the present embodiment, comprises the following steps:
(1) support pretreatment
Described carrier is honeycomb ceramic filter or through type ceramic honey comb, is soaked by described carrier in nitric acid, cleans post-drying;
(2) carrier sensitization
Immersed in sensitizing solution by the carrier handled well in step (1), the solvent of described sensitizing solution is deionized water and CH
3oH, solute is SnCl
2and C
2hF
3o
2;
(3) support-activated
By the carrier through sensitization in step (2), take out and first use washed with methanol, then use pure water rinsing, immerse in activating solution afterwards; Described activating solution is by AgNO
3be dissolved in wiring solution-forming in pure water, then carry out titration with ammoniacal liquor until brown oxidation silver precipitation disappears, namely obtain activating solution;
(4) electroless deposition
Preparation precious metal salt solution: precious metal salt solution is the solution containing one or more soluble-salts in platinum, palladium, rhodium;
Configuration plating solution: described plating solution is that described precious metal salt solution is added complexing agent, and described complexing agent is ammoniacal liquor;
Deposition reaction: by carrier activated in step (3), takes out and first uses washed with methanol, then use pure water rinsing, immerses in plating solution afterwards; Immerse in plating solution to start to react from carrier and constantly add reducing agent to reaction terminal procedure, described reducing agent is the one in hydrazine hydrate, hypophosphites, phosphite, borine, trimethylamine, formaldehyde.
Embodiment 1
The present embodiment is prepared as example with single platinum catalyst, is intended to Nobel-metal catalyst preparation method disclosed by the invention is described.
(1) support pretreatment
Carrier is wall-flow type wall-flow type cordierite honeycomb ceramic carrier, and purchased from Yixing Prince Ceramics Co., Ltd., Φ 127 × 118mm, 200 orders, break into pieces, get 2cm square block nitric acid dousing carrier 24 hours of 5%, clean, dry 10 hours at 90 DEG C with pure water.Stand-by.
(2) carrier sensitization
The carrier handled well in step (1) is put into sensitizing solution, stops 60min, preparation 250ml sensitizing solution, the solvent of described sensitizing solution is deionized water and the CH of volume ratio 1:1
3oH, solute is SnCl
2and C
2hF
3o
2, SnCl
2concentration be 22mmol/L, C
2hF
3o
2concentration be 70mmol/L.
(3) support-activated
By the carrier through sensitization in step (2), take out and first use washed with methanol, use pure water rinsing again, immerse afterwards in activating solution, stop 20min, described activating solution AgNO3 is dissolved in pure water the solution being made into 35mmol/L, then carries out titration until brown oxidation silver precipitation disappears with the ammonia spirit of 37%, namely obtain activating solution.
(4) electroless deposition
(4.1) precious metal salt solution is prepared, described precious metal salt solution solute K
2ptCl
6, solvent is pure water, and concentration is 1mmol/L;
(4.2) prepare surfactant solution, described surfactant solution solute is neopelex, and solvent is pure water, and concentration is 0.14mol/L;
(4.3) prepare plating solution A, described plating solution A be by precious metal salt solution obtained in (4.1) and ammoniacal liquor by volume 1:1.5 mix and obtain; Ammoniacal liquor is the ammoniacal liquor of 37% commercially available concentration;
(4.4) plating solution B is prepared, surfactant solution obtained in (4.2) is added reductant solution mixing to obtain by described plating solution B, reductant solution is 1mol/L hydrazine hydrate aqueous solution, and wherein the volume ratio of surfactant solution and reductant solution is 1:25;
(4.5) by carrier activated in step (3), take out and first use washed with methanol, use pure water rinsing again, immerse afterwards in plating solution A, plating solution B is added in plating solution A and obtains plating solution C, wherein the volume ratio of plating solution B and plating solution A is 1:1.5,120min is soaked in this solution at 55 DEG C, in precipitation process, a plating solution is upgraded every 40min, upgrade the hydrazine hydrate aqueous solution adding a 1mol/L in the middle of plating solution interval twice, after namely upgrading plating solution, 20min adds a hydrazine hydrate, and the volume ratio of the hydrazine hydrate solution added and plating solution B is 1:2.
(4.6), after electroless deposition, sample is clean by pure water rinsing, and 25% HNO
3soak 12h in solution, taking-up is clean by pure water rinsing, dries at 120 DEG C, i.e. obtained single platinum catalyst.
Embodiment 2
(1) support pretreatment
Carrier is honeycomb ceramic filter, the nitric acid dousing carrier with 30% 24 hours, cleans with pure water, dries 10 hours at 120 DEG C.
(2) carrier sensitization
The carrier handled well in step (1) is put into sensitizing solution, and stop 90min, the solvent of described sensitizing solution is deionized water and the CH of volume ratio 1:1
3oH, solute is SnCl
2and C
2hF
3o
2, SnCl
2concentration be 27mmol/L, C
2hF
3o
2concentration be 80mmol/L.
(3) support-activated
By the carrier through sensitization in step (2), take out and first use washed with methanol, then use pure water rinsing, immerse in activating solution afterwards, stop 30min, described activating solution is by AgNO
3be dissolved in pure water the solution being made into 40mmol/L, then carry out titration until brown oxidation silver precipitation disappears with the ammoniacal liquor of 37%, namely obtain activating solution.
(4) electroless deposition
(4.1) prepare precious metal salt solution, described precious metal salt solution solute is Pd (NH
3)
4cl
2, solvent is pure water, and concentration is 5mmol/L;
(4.2) prepare surfactant solution, described surfactant solution solute is neopelex, and solvent is pure water, and concentration is 0.3mol/L;
(4.3) prepare plating solution A, described plating solution A be by precious metal salt solution obtained in (4.1) and ammoniacal liquor by volume 1:2 mix and obtain; Ammoniacal liquor is the ammoniacal liquor of 37% commercially available concentration;
(4.4) prepare plating solution B, surfactant solution obtained in (4.2) is added reducing agent to obtain by described plating solution B, and reducing agent is NaH
2pO
2h
2the O aqueous solution, concentration is 7.5mol/L, and wherein the volume ratio of reductant solution and surfactant is 50:1;
(4.5) by carrier activated in step (3), take out and first use washed with methanol, use pure water rinsing again, immerse in plating solution A afterwards, afterwards plating solution B is added in plating solution A, wherein the volume ratio of plating solution B and plating solution A is 1:3, at 70 DEG C, soak 150min in this solution, in precipitation process, primary sedimentation solution will be upgraded every 40min, upgrade in the middle of plating solution interval, need in plating solution, add a 7.5mol/LNaH for twice
2pO
2h
2the O aqueous solution, after namely upgrading plating solution, 20min adds a NaH
2pO
2h
2the O aqueous solution, the NaH added
2pO
2h
2the volume ratio of O solution and plating solution B is 1:2.
(4.6), after electroless deposition, sample is clean by pure water rinsing, and 25% HNO
3soak 24h in solution, taking-up is clean by pure water rinsing, dries at 120 DEG C, i.e. obtained single palladium nanocatalyst.
Embodiment 3
(1) support pretreatment
Carrier is through type ceramic honey comb, the nitric acid dousing carrier with 5% 24 hours, cleans with pure water, dries 10 hours at 90 DEG C.
(2) carrier sensitization
The carrier handled well in step (1) is put into sensitizing solution, and stop 30min, the solvent of described sensitizing solution is deionized water and the CH of volume ratio 1:1
3oH, solute is SnCl
2and C
2hF
3o
2, SnCl
2concentration be 17mmol/L, C
2hF
3o
2concentration be 60mmol/L.
(3) support-activated
By the carrier through sensitization in step (2), take out and first use washed with methanol, then use pure water rinsing, immerse in activating solution afterwards, stop 20min, described activating solution is by AgNO
3be dissolved in pure water the solution being made into 30mmol/L, then carry out titration until brown oxidation silver precipitation disappears with the ammoniacal liquor of 37%, namely obtain activating solution.
(4) electroless deposition
(4.1) prepare precious metal salt solution, described precious metal salt solution solute is Pt (NH
3)
2(NO
2)
2, solvent is pure water, and concentration is 0.1mmol/L;
(4.2) prepare surfactant solution, described surfactant solution solute is neopelex, and solvent is pure water, and concentration is 0.1mol/L;
(4.3) prepare plating solution A, described plating solution A be by precious metal salt solution obtained in (4.1) and ammoniacal liquor by volume 1:2 mix and obtain; Ammoniacal liquor is the ammoniacal liquor of 37% commercially available concentration;
(4.4) prepare plating solution B, surfactant solution obtained in (4.2) is added reducing agent to obtain by described plating solution B, and reducing agent is Na
2hPO
35H
2o, concentration is 8mol/L, and wherein the volume ratio of reductant solution and surfactant is 15:1;
(4.5) by carrier activated in step (3), take out and first use washed with methanol, use pure water rinsing again, immerse afterwards in plating solution A, add in plating solution A by plating solution B afterwards, wherein the volume ratio of plating solution B and plating solution A is 1:1, at 40 DEG C, soak 80min in this solution, in precipitation process, reducing agent is 8mol/LNa
2hPO
35H
2o solution, and need to upgrade primary sedimentation solution every 30min, upgrade in the middle of plating solution interval, need in plating solution, add a 8mol/LNa for twice
2hPO
35H
2the O aqueous solution, the Na added
2hPO
35H
2the volume ratio of the O aqueous solution and plating solution B is 1:2.
(4.6), after electroless deposition, sample is clean by pure water rinsing, and 25% HNO
3soak 12h in solution, taking-up is clean by pure water rinsing, dries at 120 DEG C, i.e. obtained single platinum noble metals nanocatalyst.
Embodiment 4
(1) support pretreatment
Carrier is honeycomb ceramic filter, the nitric acid dousing carrier with 10% 24 hours, cleans with pure water, dries 10 hours at 100 DEG C.
(2) carrier sensitization
The carrier handled well in step (1) is put into sensitizing solution, and stop 50min, the solvent of described sensitizing solution is deionized water and the CH of volume ratio 1:1
3oH, solute is SnCl
2and C
2hF
3o
2, SnCl
2concentration be 20mmol/L, C
2hF
3o
2concentration be 65mmol/L.
(3) support-activated
By the carrier through sensitization in step (2), take out and first use washed with methanol, then use pure water rinsing, immerse in activating solution afterwards, stop 18min, described activating solution is by AgNO
3be dissolved in pure water the solution being made into 35mmol/L, then carry out titration until brown oxidation silver precipitation disappears with the ammoniacal liquor of 37%, namely obtain activating solution.
(4) electroless deposition
(4.1) prepare precious metal salt solution, described precious metal salt solution solute is Na
2pt (OH)
6, solvent is pure water, and concentration is 2mmol/L;
(4.2) prepare surfactant solution, described surfactant solution solute is neopelex, and solvent is pure water, and concentration is 0.01mol/L;
(4.3) prepare plating solution A, described plating solution A be by precious metal salt solution obtained in (4.1) and ammoniacal liquor by volume 1:3 mix and obtain; Ammoniacal liquor is the ammoniacal liquor of 37% commercially available concentration;
(4.4) prepare plating solution B, surfactant solution obtained in (4.2) is added reducing agent to obtain by described plating solution B, and reducing agent is 7mol/LNaBH
4the aqueous solution, wherein the volume ratio of reductant solution and surfactant solution is 28:1;
(4.5) by carrier activated in step (3), take out and first use washed with methanol, then use pure water rinsing, immerse in plating solution A afterwards, afterwards plating solution B is added in plating solution A, wherein the volume ratio of plating solution B and plating solution A is 1:1.6, soaks 100min in this solution, in precipitation process at 50 DEG C, in precipitation process, primary sedimentation solution to be upgraded every 50min, upgrade in the middle of plating solution interval, need in plating solution, add a 7mol/LNaBH
4the aqueous solution, the NaBH added
4the volume ratio of the aqueous solution and plating solution B is 1:2.
(4.6), after electroless deposition, sample is clean by pure water rinsing, and 25% HNO
3soak 14h in solution, taking-up is clean by pure water rinsing, dries at 120 DEG C, i.e. obtained single platinum nano catalyst.
Embodiment 5
(1) support pretreatment
Carrier is honeycomb ceramic filter or through type ceramic honey comb, the nitric acid dousing carrier with 12% 24 hours, cleans with pure water, dries 10 hours at 110 DEG C.
(2) carrier sensitization
The carrier handled well in step (1) is put into sensitizing solution, and stop 70min, the solvent of described sensitizing solution is deionized water and the CH of volume ratio 1:1
3oH, solute is SnCl
2and C
2hF
3o
2, SnCl
2concentration be 25mmol/L, C
2hF
3o
2concentration be 70mmol/L.
(3) support-activated
By the carrier through sensitization in step (2), take out and first use washed with methanol, then use pure water rinsing, immerse in activating solution afterwards, stop 25min, described activating solution is by AgNO
3be dissolved in pure water the solution being made into 36mmol/L, then carry out titration until brown oxidation silver precipitation disappears with the ammoniacal liquor of 37%, namely obtain activating solution.
(4) electroless deposition
(4.1) prepare precious metal salt solution, described precious metal salt solution solute is PdCl
2, solvent is pure water, and concentration is 2.5mmol/L;
(4.2) prepare surfactant solution, described surfactant solution solute is neopelex, and solvent is pure water, and concentration is 0.11mol/L;
(4.3) prepare plating solution A, described plating solution A be by precious metal salt solution obtained in (4.1) and ammoniacal liquor by volume 1:2.5 mix and obtain; Ammoniacal liquor is the ammoniacal liquor of 37% commercially available concentration;
(4.4) prepare plating solution B, surfactant solution obtained in (4.2) is added reducing agent to obtain by described plating solution B, and reducing agent is the formalin of 2mol/L, and wherein the volume ratio of reducing agent and surfactant solution is 30:1.
(4.5) by carrier activated in step (3), take out and first use washed with methanol, use pure water rinsing again, immerse afterwards in plating solution A, afterwards plating solution B is added in plating solution A, wherein the volume ratio of plating solution B and plating solution A is 1:1.4,90min is soaked in this solution at 60 DEG C, in precipitation process, primary sedimentation solution to be upgraded every 40min, upgrade in the middle of plating solution interval for twice, in plating solution, add the formalin of a 2mol/L, the volume ratio of the formalin added and plating solution B is 1:2.
(4.6), after electroless deposition, sample is clean by pure water rinsing, and 25% HNO
3soak 10h in solution, taking-up is clean by pure water rinsing, dries at 120 DEG C, i.e. obtained noble metal nano catalyst.
Embodiment 6
(1) support pretreatment
Carrier is honeycomb ceramic filter, the nitric acid dousing carrier with 15% 24 hours, cleans with pure water, dries 10 hours at 120 DEG C.
(2) carrier sensitization
The carrier handled well in step (1) is put into sensitizing solution, and stop 80min, the solvent of described sensitizing solution is deionized water and the CH of volume ratio 1:1
3oH, solute is SnCl
2and C
2hF
3o
2, SnCl
2concentration be 25mmol/L, C
2hF
3o
2concentration be 80mmol/L.
(3) support-activated
By the carrier through sensitization in step (2), take out and first use washed with methanol, then use pure water rinsing, immerse in activating solution afterwards, stop 22min, described activating solution is by AgNO
3be dissolved in pure water the solution being made into 38mmol/L, then carry out titration until brown oxidation silver precipitation disappears with the ammoniacal liquor of 37%, namely obtain activating solution.
(4) electroless deposition
(4.1) prepare precious metal salt solution, described precious metal salt solution solute is Pd (NH
3)
4cl
2, solvent is pure water, and concentration is 2mmol/L;
(4.2) prepare surfactant solution, described surfactant solution solute is neopelex, and solvent is pure water, and concentration is 0.3mol/L;
(4.3) prepare plating solution A, described plating solution A be by precious metal salt solution obtained in (4.1) and ammoniacal liquor by volume 1:4 mix and obtain; Ammoniacal liquor is the ammoniacal liquor of 37% commercially available concentration;
(4.4) prepare plating solution B, surfactant solution obtained in (4.2) is added reducing agent to obtain by described plating solution B, and reducing agent is the trimethylamine aqueous solution of 2mol/L, and wherein the volume ratio of reducing agent and surfactant solution is 10:1;
(4.5) by carrier activated in step (3), take out and first use washed with methanol, use pure water rinsing again, immerse afterwards in plating solution A, afterwards plating solution B is added in plating solution A, wherein the volume ratio of plating solution B and plating solution A is 1:2,150min is soaked in this solution at 66 DEG C, in precipitation process, primary sedimentation solution to be upgraded every 40min, upgrade in the middle of plating solution interval, need the trimethylamine aqueous solution adding a 2mol/L in plating solution, the volume ratio of the trimethylamine aqueous solution added and plating solution B is 1:2.
(4.6), after electroless deposition, sample is clean by pure water rinsing, and 25% HNO
3soak 18h in solution, taking-up is clean by pure water rinsing, dries at 120 DEG C, i.e. obtained single palladium nanocatalyst.
Embodiment 7
(1) support pretreatment
Carrier is through type ceramic honey comb, the nitric acid dousing carrier with 25% 24 hours, cleans with pure water, dries 10 hours at 100 DEG C.
(2) carrier sensitization
The carrier handled well in step (1) is put into sensitizing solution, and stop 70min, the solvent of described sensitizing solution is deionized water and the CH of volume ratio 1:1
3oH, solute is SnCl
2and C
2hF
3o
2, SnCl
2concentration be 20mmol/L, C
2hF
3o
2concentration be 63mmol/L.
(3) support-activated
By the carrier through sensitization in step (2), take out and first use washed with methanol, then use pure water rinsing, immerse in activating solution afterwards, stop 10min, described activating solution is by AgNO
3be dissolved in pure water the solution being made into 40mmol/L, then carry out titration until brown oxidation silver precipitation disappears with the ammoniacal liquor of 37%, namely obtain activating solution.
(4) electroless deposition
(4.1) prepare precious metal salt solution, described precious metal salt solution solute is Na
3rhCl
6, solvent is pure water, and concentration is 10mmol/L;
(4.3) prepare plating solution A, described plating solution A be by precious metal salt solution obtained in (4.1) and ammoniacal liquor by volume 1:2 mix and obtain; Ammoniacal liquor is the ammoniacal liquor of 37% commercially available concentration;
(4.4) prepare plating solution B, described plating solution B is reductant solution, and reducing agent is the hydrazine hydrate aqueous solution of 1mol/L;
(4.5) by carrier activated in step (3), take out and first use washed with methanol, use pure water rinsing again, immerse afterwards in plating solution A, afterwards plating solution B is added in plating solution A, wherein the volume ratio of plating solution B and plating solution A is 1:2, at 62 DEG C, soak 20min in this solution, carries out electroless deposition.
(4.6), after electroless deposition, sample is clean by pure water rinsing, and 25% HNO
3soak 12h in solution, taking-up is clean by pure water rinsing, dries at 120 DEG C, i.e. obtained single rhodium nanocatalyst.
Fig. 2 is the single platinum catalyst surface sweeping Electronic Speculum figure in embodiment 1 with honeycomb ceramic filter prepared by carrier, uses the K of 1mmol/L
2ptCl
6as precious metal precipitation solution, hydrazine hydrate is reducing agent.Wherein a) for the SEM of empty vectors schemes, b), c), d) for catalyst granules SEM under different scale schemes, the noble metal catalyst that as we can see from the figure prepared by the present invention is evenly distributed on honeycomb ceramic filter micropore hole wall surface, decentralization is high, density is large, and single Pt catalyst granule domain size distribution is 50 ~ 100nm.
The single platinum nano catalyst EDX of Fig. 3 prepared by embodiment 1 schemes, and in figure, the platinum load capacity of gauge point is 7.44% (w/w), and the load capacity of zonule platinum is 1.08% (w/w).
Fig. 4 is with single platinum catalyst scanning electron microscope (SEM) photograph that through type ceramic honey comb is prepared for carrier in embodiment 3, uses the Pt (NH of 0.1mmol/L
3)
2(NO
2)
2as precious metal precipitation solution, Na
2hPO
35H
2o is reducing agent.Wherein scheme a) be 2.48 × 1.78 μm SEM figure, figure is b) the SEM image after amplifying in white box in a), and platinum nano catalyst is uniformly distributed at through type honeycomb ceramic carrier channel surfaces, and density is larger, become popped rice shape, particle size range 50 ~ 150nm.
The single platinum nano catalyst EDX of Fig. 5 prepared by embodiment 3 schemes, and in figure, in marked region, the load capacity of platinum is 13.25% (w/w).
The single platinum nano catalyst of Fig. 6 prepared by embodiment 4, uses the Na of 2mmol/L
2pt (OH)
6as precious metal precipitation solution, NaBH
4for reducing agent.Figure is a) empty carrier, b), c) and d) be respectively the SEM after the load platinum catalyst of different scale to scheme, Pt nanoparticle is very intensive in the distribution of honeycomb ceramic filter hole wall surface, and (figure d), substantially increases the contact area of soot particulate and catalyst to define platinum cluster structure.
The single platinum nano catalyst EDX of Fig. 7 prepared by embodiment 4 schemes, and in figure, in marked region, the load capacity of platinum is 14.85% (w/w).
Above-described embodiment is illustrative principle of the present invention and effect thereof only, but not for limiting the present invention.Any person skilled in the art scholar all without prejudice under spirit of the present invention and category, can modify above-described embodiment or changes.Therefore, such as have in art usually know the knowledgeable do not depart from complete under disclosed spirit and technological thought all equivalence modify or change, must be contained by claim of the present invention.
Claims (2)
1. a Vehicle Exhaust Gas Cleaning Catalysts painting method, is characterized in that, comprises the steps:
(1) support pretreatment
Described carrier is honeycomb ceramic filter or through type ceramic honey comb, is soaked by described carrier in nitric acid, cleans post-drying;
(2) carrier sensitization
Immersed in sensitizing solution by the carrier handled well in step (1), the solvent of described sensitizing solution is deionized water and CH
3oH, solute is SnCl
2and C
2hF
3o
2;
(3) support-activated
By the carrier through sensitization in step (2), take out and first use washed with methanol, then use pure water rinsing, immerse in activating solution afterwards; Described activating solution is by AgNO
3be dissolved in wiring solution-forming in pure water, then carry out titration with ammoniacal liquor until brown oxidation silver precipitation disappears, namely obtain activating solution;
(4) electroless deposition
Preparation precious metal salt solution: precious metal salt solution is the aqueous solution containing one or more soluble-salts in platinum, palladium, rhodium;
Configuration plating solution: described plating solution is that described precious metal salt solution is added complexing agent, and described complexing agent is ammoniacal liquor;
Deposition reaction: by carrier activated in step (3), takes out and first uses washed with methanol, then use pure water rinsing, immerses in plating solution afterwards; Immerse in plating solution to start to react from carrier and constantly add reducing agent to reaction terminal procedure, described reducing agent is the one in hydrazine hydrate, hypophosphites, phosphite, borine, trimethylamine, formaldehyde; Described step (1) support pretreatment is further: carrier is honeycomb ceramic filter or through type ceramic honey comb, the nitric acid dousing carrier with 5 ~ 30% 24 hours, cleans with pure water, dries 10 hours at 90 ~ 120 DEG C;
Described step (2) carrier sensitization is further: the carrier handled well in step (1) is put into sensitizing solution, and stop 30 ~ 90min, the solvent of described sensitizing solution is deionized water and the CH of volume ratio 1:1
3oH, solute is SnCl
2and C
2hF
3o
2, SnCl
2concentration be 17 ~ 27mmol/L, C
2hF
3o
2concentration be 60 ~ 80mmol/L;
Described step (3) is support-activated is further: by the carrier through sensitization in step (2), takes out and first uses washed with methanol, then use pure water rinsing, and immerse in activating solution afterwards, stop 10 ~ 30min, described activating solution is by AgNO
3be dissolved in pure water the solution being made into 30 ~ 40mmol/L, then carry out titration until brown oxidation silver precipitation disappears with the ammoniacal liquor of 37%, namely obtain activating solution;
In described step (4), preparation precious metal salt solution is further:
(4.1) prepare precious metal salt solution, described precious metal salt solution solute is one or more soluble-salts containing platinum, palladium, rhodium, and solvent is pure water, and concentration is 0.1 ~ 10mmol/L;
Comprise before carrier immerses plating solution in described step (4):
(4.2) prepare surfactant solution, described surfactant solution solute is neopelex, and solvent is pure water, and concentration is 0.01 ~ 0.3mol/L;
In described step (4), preparation plating solution is further:
(4.3) prepare plating solution A, described plating solution A be by obtained precious metal salt solution and ammoniacal liquor by volume 1:1.5 ~ 1:4 mix and obtain;
In described step (4), preparation plating solution also comprises:
(4.4) plating solution B is prepared, described plating solution B is described reductant solution or volume ratio is the described surfactant solution of 1:10 ~ 1:50 and the mixed liquor of reductant solution, and described reductant solution is selected from the following solution that concentration is 1-10mol/L: hydrazine hydrate aqueous solution, the hypophosphites aqueous solution, the phosphite aqueous solution, the borine aqueous solution, trimethylamine aqueous solution, formalin;
In described step (4), deposition reaction is further:
(4.5) by carrier activated in step (3), take out and first use washed with methanol, use pure water rinsing again, immerse afterwards in plating solution A, afterwards plating solution B is added in plating solution A and obtain plating solution C, wherein the volume ratio of plating solution B and plating solution A is 1:1 ~ 1:3,20min ~ 150min is soaked in this solution at 40 ~ 70 DEG C, and upgrade once described plating solution C every 25 ~ 50min, in plating solution, add once described reductant solution in the middle of the interval of twice renewal plating solution, the described reductant solution added and the volume ratio of plating solution B are 1:2.
2. Vehicle Exhaust Gas Cleaning Catalysts painting method according to claim 1, after it is characterized in that electroless deposition, also comprises step:
(4.6), after electroless deposition, sample is clean by pure water rinsing, and 25% HNO
3soak 12 ~ 24h in solution, taking-up is clean by pure water rinsing, dries at 120 DEG C, i.e. obtained noble metal nano catalyst.
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| CN110833831B (en) * | 2019-11-07 | 2022-11-01 | 上海纳米技术及应用国家工程研究中心有限公司 | Preparation method of chromium-cobalt-based nitric oxide normal-temperature normal-pressure catalyst, product and application thereof |
| CN114959665B (en) * | 2022-04-25 | 2024-03-01 | 金川集团股份有限公司 | Preparation method of colloid palladium activating solution for electroless copper plating of printed circuit board |
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|---|---|---|---|---|
| CN101003023A (en) * | 2006-01-19 | 2007-07-25 | 清华大学 | Method for preparing catalyst to purify automobile tail gas |
| CN101176854A (en) * | 2007-12-12 | 2008-05-14 | 吉林大学 | Method for preparing diesel truck vent gas four-effect catalyzer with alloy metal as carrier |
| CN101269335A (en) * | 2008-05-09 | 2008-09-24 | 吉林大学 | Sulfureous resistant four-effect catalyst for purifying tail gas of vehicle |
| EP1994982A1 (en) * | 2007-03-30 | 2008-11-26 | Fujifilm Corporation | Catalyst body which uses an anodized layer |
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2014
- 2014-06-04 CN CN201410244144.1A patent/CN103977842B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101003023A (en) * | 2006-01-19 | 2007-07-25 | 清华大学 | Method for preparing catalyst to purify automobile tail gas |
| EP1994982A1 (en) * | 2007-03-30 | 2008-11-26 | Fujifilm Corporation | Catalyst body which uses an anodized layer |
| CN101176854A (en) * | 2007-12-12 | 2008-05-14 | 吉林大学 | Method for preparing diesel truck vent gas four-effect catalyzer with alloy metal as carrier |
| CN101269335A (en) * | 2008-05-09 | 2008-09-24 | 吉林大学 | Sulfureous resistant four-effect catalyst for purifying tail gas of vehicle |
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