CN104437487A - Catalyst applied to preceding-stage three-way catalytic converter - Google Patents
Catalyst applied to preceding-stage three-way catalytic converter Download PDFInfo
- Publication number
- CN104437487A CN104437487A CN201410604351.3A CN201410604351A CN104437487A CN 104437487 A CN104437487 A CN 104437487A CN 201410604351 A CN201410604351 A CN 201410604351A CN 104437487 A CN104437487 A CN 104437487A
- Authority
- CN
- China
- Prior art keywords
- catalyst
- prime
- catalyzing unit
- ternary catalyzing
- nitric acid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Catalysts (AREA)
Abstract
The invention discloses a catalyst applied to a preceding-stage three-way catalytic converter. The catalyst comprises a carrier and an active material, wherein the active material consists of precious metals and a cocatalyst; the precious metals consist of palladium nitrate and rhodium nitrate at a weight ratio of 14.3 to 1; the cocatalyst consists of aluminum oxide, cerium-zirconium powder, pseudo-boehmite, de-ionized water and nitric acid. Aiming at a front state of the three-way catalytic converter, the catalyst has an excellent purification effect on tail gas produced during the cold starting of automobiles.
Description
Technical field
The present invention relates to the catalyst field of purifying vehicle exhaust, especially relate to the catalyst for automobile three-way catalysts prime.
Background technology
The major pollutants of vehicle exhaust are carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide, utilize the ternary catalyzing unit being arranged on gas extraction system carbon monoxide, oxidizing hydrocarbon can be become carbon dioxide and water, reduction of nitrogen oxide is become nontoxic nitrogen simultaneously, realize the purification of tail gas; Ternary catalyzing unit, is arranged on most important outer purifier in automobile exhaust system, and carbon monoxide, hydrocarbon and the oxynitrides of being discharged by vehicle exhaust complete purified treatment through oxidation or reduction.When the vehicle exhaust of high temperature is by purifier, the three-way catalyst in ternary catalyzing unit strengthens the activity of carbon monoxide, oxidation of nitrogen thing and hydrocarbon, promotes that it carries out certain redox chemical reaction; But high-temperature tail gas can reduce the activity of noble metal.Three-way catalyst is made up of two parts: carrier and the active catalytic species useful be overlying on carrier; Active catalytic species useful selects noble metal usually, as one or more of platinum, palladium and rhodium, adds oxidation material etc. in addition.
Current exhaust emissions regulation is strict, especially adds the regulation (cold start-up) required the emission compliance of cold-starting automobile; During cold start-up, temperature is lower, and the transformation efficiency of catalyst is also relatively low, meanwhile, time engine cold-start (engine air-fuel), in discarded hydrocarbon or oxynitrides content higher; Tackle in cold start-up tail gas, at present ternary catalyzing unit is divided into prime and rear class, ternary catalyzing unit prime part is mainly used for process cold start-up and produces tail gas, be applied to prime ternary catalyzing unit and rear class ternary catalyzing unit, because the difference of pollution compound in reply tail gas, also can exist and need different three-way catalysts.
Summary of the invention
The object of the invention is a kind of catalyst for prime ternary catalyzing unit vent gas treatment provided, and for the process of medium discharge capacity vehicle exhaust.
The technical solution used in the present invention is as follows:
Be applied to a catalyst for prime ternary catalyzing unit, comprise carrier and active material, described active material is made up of noble metal and co-catalyst; Described noble metal is palladium nitrate, rhodium nitrate composition, and described palladium nitrate and rhodium nitrate weight proportion are 14.3:1; Described co-catalyst is aluminium oxide, cerium zirconium powder, boehmite, deionized water, nitric acid composition.
Further preferably, described co-catalyst aluminium oxide, cerium zirconium powder, boehmite, water, nitric acid weight proportion are 1:0.4:0.1:4:0.05.
Further preferably, described carrier is honeycomb support.
Further preferably, described honeycomb support is 600 order carriers.Described carrier specification is 85*74.5, and showing that the diameter of carrier is 85mm (millimeter), is highly 74.5mm (millimeter).
Noble metal all has very high activity to the oxidation of CO, and Pd has high oxidation reaction ability to HC (hydrocarbon oxide), Rh control NO
x(oxynitrides), wherein reaction is as follows:
1) oxidation reaction of CO and HC: CO+O
2→ CO
2
2) NO
xreduction reaction (for NO):
NO+HC→N
2+H
2O+CO
2；NO+CO→N
2+CO
2。
Wherein, cerium oxide has transfer capability between trivalent cerium and quadrivalent cerium oxide, can absorb under lean-burn and fuel-rich condition and discharge oxygen, improves catalyst serviceability; Introduce Zr element and form heat endurance and the oxygen storage capacity that cerium zirconium powder (Ce-Zr, CeZr solid solution) significantly improves cerium oxide.
Boehmite, has another name called monohydrate alumina, false boehmite, can meet oxygen source and react the requirement mixing dispersion, providing a kind of oxygen source of effective abundance.
Nitric acid, for top grade is pure, 100% fuming nitric aicd.
In the lean-burn stage, NOx is through processes such as absorption, oxidation and diffusions, and be finally stored in material with the form of Nitrates, in the fuel-rich stage, nitrate or nitrite decompose, and discharge NOx, under the reducing agents such as HC, CO exist, be reduced to eco-friendly nitrogen.
In the application, adopt palladium nitrate and rhodium nitrate as main reductant-oxidant, add the co-catalyst of the compounds such as aluminium oxide simultaneously, be in the lean-burn stage during cold-starting automobile, the oxidized nitrate of oxynitrides, form the balance of nitrate anion, under fuel-rich condition, nitrates decompose; The compounds such as precious metal palladium and rhodium catalysis nitrogen oxide; Hydrogen-storing material aluminium oxide, cerium zirconium powder, boehmite etc. improve the oxidability of precious metal palladium and rhodium, the oxygen function of storing of the aluminium oxide (hydrogen-storing material) be used alone makes the Rh of its load more easily be in oxidation state, the activity of Rh and the Pd catalysis oxynitrides reduction of oxidation state is lower, and the compound hydrogen-storing material of cerium zirconium powder significantly improves the activity of Rh catalytic reduction oxynitrides; Intend thin water aluminium pore volume comparatively large, be conducive to macromolecular compound to catalyst granules diffusion inside, high-specific surface area is conducive to the dispersion of active metal, improves the reactivity worth of catalyst.Co-catalyst add nitric acid (pure nitric acid), form the dynamic equilibrium of the nitrate anion between catalyst and oxidation product.Ratio between co-catalyst also can form the dynamic equilibrium between catalyst component, mutually supplements between hydrogen-storing material, improves co-catalyst overall to noble metal supporting capacity.Acid is as reducing agent, and the electron number that red fuming nitric acid (RFNA) average per molecule nitric acid obtains is less, and the reduzate of red fuming nitric acid (RFNA) is mainly nitrogen dioxide etc., and nitric acid can as the intermediate equilibria thing in tail gas oxynitrides oxidation-reduction process.
The catalyst being applied to prime ternary catalyzing unit provided by the invention, is directed to the prime of ternary catalyzing unit, has outstanding clean-up effect to the tail gas produced during cold-starting automobile.
Detailed description of the invention
Below in conjunction with the embodiment of the present invention, be clearly and completely described technical scheme of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
Embodiment 1 is applied to the catalyst of prime ternary catalyzing unit
Be applied to the catalyst of prime ternary catalyzing unit, comprise carrier and active material; Active material is made up of noble metal and co-catalyst; Noble metal is palladium nitrate and rhodium nitrate composition, and the weight proportion of palladium nitrate and rhodium nitrate is: 14.3:1;
Co-catalyst is made up of aluminium oxide, cerium zirconium powder, boehmite, deionized water, nitric acid; Wherein, the weight proportion of aluminium oxide, cerium zirconium powder, boehmite, deionized water and nitric acid is: 1:0.4:0.1:4:0.05; Wherein, the part by weight of co-catalyst and noble metal is: (1 ~ 3): (2 ~ 0.1).The nitric acid adopted is pure nitric acid (fuming nitric aicd), as the fuming nitric aicd of Merck & Co., Inc. (Merck company).
Catalyst manufacturing process is as follows: be first coated on carrier by the slip of co-catalyst, and in 400 DEG C ~ 600 DEG C roasting temperatures 1 ~ 5 hour, completes the preparation of first step coating; Subsequently, the rhodium nitrate of noble metal and the slip of palladium nitrate are coated on the above-mentioned carrier completing first step coating, 400 DEG C ~ 600 DEG C roastings 1 ~ 5 hour, complete final preparation.
Embodiment 2 is applied to the catalyst of prime ternary catalyzing unit
Be applied to the catalyst of prime ternary catalyzing unit, comprise carrier and active material; Active material is made up of noble metal and co-catalyst; Noble metal is palladium nitrate and rhodium nitrate composition, and the weight proportion of palladium nitrate and rhodium nitrate is: 14.3:1; Co-catalyst is made up of aluminium oxide, cerium zirconium powder, boehmite, deionized water, nitric acid; Wherein, the weight proportion of aluminium oxide, cerium zirconium powder, boehmite, deionized water and nitric acid is: 1:0.4:0.1:4:0.05.
Catalyst manufacturing process is as follows: when rear class three-way catalyst is prepared, and selects the preparation method that this area routine is selected; First the slip of co-catalyst is coated on carrier, and in 400 DEG C ~ 600 DEG C roasting temperatures 1 ~ 5 hour, completes the preparation of first step coating; Subsequently, the rhodium nitrate of noble metal and the slip of palladium nitrate are coated on the above-mentioned carrier completing first step coating, 400 DEG C ~ 600 DEG C roastings 1 ~ 5 hour, complete final preparation; Carrier adopts honeycomb support, and the order number of honeycomb support is 600 orders, and carrier specification is 85*74.5.
The catalyst sample obtained in embodiment 1 and embodiment 2 is applied to the car load emission test of Hua Tai motor corporation, car load emission test carries out according to ECE and EUDC circulation, and testing vehicle engine displacement is 1.8L, especially cold-start phase; Emission test result is as shown in table 1.
Table 1:
With reference in table 1, the catalyst being applied to prime ternary catalyzing unit provided in embodiment 1 and embodiment 2 has the disposal ability of outstanding exhaust pollutant, the purified treatment ability of oxynitrides when being especially directed to cold-starting automobile.
The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (5)
1. be applied to a catalyst for prime ternary catalyzing unit, comprise carrier and active material, it is characterized in that: described active material is made up of noble metal and co-catalyst; Described noble metal is palladium nitrate, rhodium nitrate composition, and described palladium nitrate and rhodium nitrate weight proportion are 14.3:1; Described co-catalyst is aluminium oxide, cerium zirconium powder, boehmite, deionized water, nitric acid composition.
2. a kind of catalyst being applied to prime ternary catalyzing unit as claimed in claim 1, is characterized in that: described co-catalyst aluminium oxide, cerium zirconium powder, boehmite, water, nitric acid weight proportion are 1:0.4:0.1:4:0.05.
3. a kind of catalyst being applied to prime ternary catalyzing unit as claimed in claim 1 or 2, is characterized in that: described carrier is honeycomb support.
4. a kind of catalyst being applied to prime ternary catalyzing unit as claimed in claim 3, is characterized in that: described honeycomb support is 600 order carriers.
5. a kind of catalyst being applied to prime ternary catalyzing unit as claimed in claim 4, is characterized in that: described carrier specification is 85*74.5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410604351.3A CN104437487A (en) | 2014-10-31 | 2014-10-31 | Catalyst applied to preceding-stage three-way catalytic converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410604351.3A CN104437487A (en) | 2014-10-31 | 2014-10-31 | Catalyst applied to preceding-stage three-way catalytic converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104437487A true CN104437487A (en) | 2015-03-25 |
Family
ID=52884696
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410604351.3A Pending CN104437487A (en) | 2014-10-31 | 2014-10-31 | Catalyst applied to preceding-stage three-way catalytic converter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104437487A (en) |
-
2014
- 2014-10-31 CN CN201410604351.3A patent/CN104437487A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103433057B (en) | Three-way catalyst used for automobile emission purification and preparation method thereof | |
| JP3291086B2 (en) | Exhaust gas purification catalyst and exhaust gas purification method | |
| JP2979809B2 (en) | Exhaust gas purification catalyst and method for producing the same | |
| JP3391878B2 (en) | Exhaust gas purification catalyst | |
| US20080045404A1 (en) | Catalyst containing little or no rhodium for purifying exhaust gases of internal combustion engine | |
| JP4012320B2 (en) | Exhaust gas purification catalyst for lean combustion engine | |
| JPS60110334A (en) | Preparation of catalyst for purifying exhaust gas | |
| JP2001232200A (en) | Ternary catalyst using rare earth metal oxide | |
| JP2773428B2 (en) | Exhaust gas purification method | |
| JPH11169712A (en) | Catalyst for purification of exhaust gas | |
| JPH01139144A (en) | Catalyst for controlling exhaust emission | |
| JP2017502824A (en) | Oxygen storage material | |
| CN103962151A (en) | Exhaut purification catalyst | |
| JPH08299793A (en) | Catalyst for purification of exhaust gas and its production | |
| JP3488487B2 (en) | Exhaust gas purification method | |
| JP2010058069A (en) | Catalyst for purification of exhaust gas for motorcycles | |
| US20070123418A1 (en) | Catalyst composition containing gallium for purifying exhaust gases of internal combustion engine | |
| JPH1147596A (en) | Catalyst for purifying exhaust gas | |
| CN104437487A (en) | Catalyst applied to preceding-stage three-way catalytic converter | |
| CN104368372A (en) | Catalyst applied to pre-stage three-way catalytic converter | |
| KR101336595B1 (en) | A catalyst for purifying exhaust gas with bimodal size distribution of supports | |
| CN104588013A (en) | Automobile three-way catalyst | |
| WO2002055194A1 (en) | Catalyst for clarification of nitrogen oxides | |
| CN104383956A (en) | Catalyst applied to rear three-way catalytic converter | |
| CN104399459A (en) | Catalyst for rear-stage three-way catalytic converter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20150325 |
|
| RJ01 | Rejection of invention patent application after publication |