CN105618043B - Catalyst, preparation method and application - Google Patents
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Abstract
The invention discloses a preparation method of a catalyst, which takes Pd and Ag as active components and CeO2‑ZrO2‑La2O3‑Al2O3The carrier is prepared by the following specific steps: 1) preparing a carrier; 2) preparation of the catalyst: weighing a certain mass of catalyst carrier, and preparing the catalyst by adopting an equal pore volume impregnation method according to different addition modes. The invention also discloses the catalyst and application thereof. The invention fully inspects the influence of the adding modes of the active components Pd and Ag in the bimetallic catalyst on the catalytic performance of methanol, and finds that the catalysts prepared by different adding modes have good catalytic activity on methanol.
Description
Technical Field
The invention relates to a catalyst, a preparation method and application, belongs to the field of chemical substances and preparation and application thereof, and particularly relates to a multifunctional methanol vehicle catalyst, a preparation method and application thereof.
Background
With the development of global economy, the automobile holding amount is increased year by year, and the contradiction between supply and demand of traditional petroleum-based automobile fuel is brought, so that the unified structure of the petroleum-based automobile fuel is changed greatly, the domestic petroleum is expected to be exhausted after 2020, the energy demand at that time is 4 times higher than that at present, 70% -80% of energy is imported, and the national energy safety is directly influenced. In addition, the current energy structure has great influence on sustainable development, mainly the atmospheric environment pollution is serious, wherein automobile exhaust gas forms the main source of atmospheric pollution, so that the development of stable, durable, economic, convenient and clean automobile alternative fuel is important for ensuring national economic sustainable development and national energy safety.
Various clean alternative energy sources such as natural gas, liquefied petroleum gas, biodiesel, synthetic fuel, alcohol fuel, ethers and the like become important ways for solving the shortage of petroleum resources. Methanol is an organic fuel with similar physical and chemical properties to gasoline, and can be prepared from natural gas, coal, biological raw materials and the like. Therefore, from the situation of China, the development of the methanol fuel is an important way for solving the problems of energy safety and sustainable development. In addition, among various alternative energy sources, the methanol synthesis process is simple, the source is wide, the price is low, and the molecular structure of the methanol synthesis process contains oxygen, so that the methanol synthesis process has the advantages of high octane number, large latent heat of vaporization and the like, and can obviously reduce HC, CO and NO in tail gas when being used as fuel singly or in a blending modeXAnd particulate matter emissions, have been of great interest. According to the test of the working condition method of the motor vehicle pollution discharge center of the State environmental protection administration, the Beijing standard gasoline and the methanol gasoline (M30) used by the same vehicle are compared, so that the carbon monoxide and the hydrocarbon are reduced by more than 30%, the sulfur emission is reduced by 20% under the same condition, the power is improved by 5.2%, the oil consumption per hundred kilometers is reduced by 5%, and the development of the clean fuel mainly comprising the methanol has very important strategic significance in the aspects of energy safety, environmental protection and sustainable development of social economy.
The popularization and the use of the methanol clean alternative energy not only relieve the energy crisis of China, but also greatly reduce the emission of the conventional pollutants in the tail gas of the motor vehicle, however, the unconventional pollutants generated in the combustion process of the methanol fuel are found to be far higher than those of gasoline and diesel vehicles in a large number of methanol vehicle tail gas emission experiments. Therefore, the methanol gasoline vehicle tail gas purification not only needs to purify conventional pollutants, but also needs to purify unconventional pollutants, and the difficulty of tail gas purification is obviously higher than that of gasoline vehicle tail gas.
Earlier researches prove that Pd has better catalytic activity on methanol, but the deep oxidation performance needs to be further improved; Ag/gamma-Al2O3For methanolAlthough the oxidation has better deep oxidation selectivity, the activity is lower than that of Pd. 5 percent Ag-0.1 percent Pd/gamma-Al is prepared by cinnabar and the like by taking silver-ammonia complex ions and ammonium chloropalladate as precursors2O3The activity of the catalyst shows that the catalytic activity of the Pd-Ag bimetallic catalyst is obviously superior to that of a single metal catalyst, and the Pd-Ag system does not have the phenomenon of CO inhibition. However, most of the catalyst carriers studied before are gamma-Al2O3It is difficult to reduce the activity of Ag due to the tendency of Ag to aggregate. As is well known, CeO2-ZrO2Has the characteristics of better oxidation-reduction characteristic, can promote the dispersion of noble metal to a certain extent so as to improve the low-temperature catalytic oxidation performance of the catalyst, and the like, so that the catalyst is widely applied to three-way catalysts. And researches also find that Ce can promote Ag in gamma-Al2O3Dispersion on a support, La reduces the light-off temperature of methanol and La and Ce act together to increase the conversion of methanol to CO2The research shows that electronic effects exist between Pd and Ag metals and between the metals and the carrier, the effect promotes the interface of the metals and the carrier to generate a large amount of active oxygen species, so that the low-temperature activity of the catalyst is improved, the oxidation rate of the catalyst is also improved, and the deep oxidation performance of the catalyst on methanol is further improved.
Nevertheless, in the bimetallic system, the adding mode of the active component directly affects the active center on the surface of the carrier, the redox performance of the catalyst and the flow performance of active oxygen, so the inventor continuously examines the influence of the adding mode of the active component Pd and Ag in the bimetallic catalyst on the catalytic performance of methanol on the basis of the previous research result; meanwhile, the actual composition of the tail gas of the methanol gasoline vehicle is simulated, the catalytic purification performance of the improved catalyst on the conventional pollutants CO, NO and HC and the unconventional pollutant methanol in the tail gas is investigated, and then the multifunctional methanol vehicle catalyst is developed.
Disclosure of Invention
The invention aims to provide a preparation method of a catalyst, which can be applied to multifunctional methanol vehicle tail gas treatment.
The invention is realized by the following steps:
a catalyst is prepared from Pd and Ag as active components and CeO2-ZrO2-La2O3-Al2O3The carrier is prepared by the following specific steps:
1) preparation of the carrier:
ZrO (CO) is added according to a certain stoichiometric ratio3)2Dissolving in concentrated nitric acid, and adding dissolved Ce (NO) in deionized water3)3.6H2O，La(NO3)3And Al (NO)3)3·9H2Mixing with O solution, adding NH3·H2Titrating O as a precipitator, controlling the pH value to be 8-10, aging after titrating, filtering, drying, and roasting the obtained powder at 600 ℃ for 5h to obtain a catalyst carrier, wherein the mol ratio of the components in the catalyst carrier is Ce: Zr: La: Al (1-10): 0.5-4): 3-30;
2) preparation of the catalyst:
weighing a certain mass of catalyst carrier, and preparing the catalyst according to different addition modes by adopting an equal pore volume impregnation method;
① adding Pd + Ag as catalyst, the preparation process comprises preparing Pd (NO) at a certain ratio3)2And AgNO3Adding a certain mass of carrier into the aqueous solution mixture, drying at 100 ℃, and roasting at 500 ℃ to obtain Pd + Ag/CeO2-ZrO2-La2O3-Al2O3(abbreviated as Pd + Ag/CZLA) catalyst powder;
② adding Ag/Pd catalyst step by preparing Pd/CZLA, adding certain mass of carrier into Pd (NO)3)2Drying in water solution at 100 deg.C, calcining at 500 deg.C to obtain catalyst powder, and adding AgNO3Drying in water solution at 100 ℃, and roasting at 500 ℃ to obtain final catalyst powder Ag/Pd/CZLA;
③ adding Pd/Ag catalyst step by step, the preparation process comprises preparing Ag/CZLA, adding a certain mass of carrier to AgNO3Drying in water solution at 100 deg.C, calcining at 500 deg.C to obtain catalyst powder, and adding into Pd (NO)3)2Drying in water solution at 100 deg.c and roasting at 500 deg.c to obtain the final catalyst powder Pd/Ag/CZLA.
The further scheme is as follows: the aging method comprises the following steps: after titration, adopting a water bath, an oil bath or a high-pressure reaction kettle, controlling the temperature to be 70-180 ℃ and the time to be 4-48h, and finishing aging.
The further scheme is as follows: the sum of the Pd and Ag contents in the catalyst powder is 1.0 wt% -2.0 wt%.
Another object of the present invention is to provide a catalyst prepared by the above method.
The invention further aims to provide application of the catalyst, which is to apply the catalyst to multifunctional methanol vehicle tail gas treatment.
The specific application method comprises the following steps: grinding the catalyst, coating the ground catalyst on a cordierite honeycomb ceramic substrate with the coating amount of 100-150g/L, drying, roasting, and then applying to multifunctional methanol vehicle tail gas treatment.
Methanol has the advantages of high octane number, large latent heat of vaporization and the like, and can obviously reduce HC, CO and NO in tail gas when being used as a substitute fuel of gasoline for vehiclesXAnd the amount of particulate matter discharged. However, during the starting and idling of the automobile, a large amount of incompletely combusted methanol and partial oxidation products are generated, and if the methanol and the partial oxidation products directly enter the atmosphere without strict purification, secondary environmental pollution is certainly caused. Because Pd has better catalytic performance on methanol and Ag has better deep oxidation performance, a bimetallic system taking Pd and Ag as active components becomes a hot point of research, but the carriers of the research system at present mostly adopt gamma-Al2O3Mainly, the activity reduction caused by easy aggregation of Ag becomes difficult in practical application; in addition, the reaction space velocity of the existing research working system is not high (18000--1) In fact, the space velocity of the tail gas of the methanol gasoline vehicle is generally 3 x 104h-1-10×104h-1Therefore, the greatest advantages and characteristics of the patent compared with the existing research are as follows:
1) and (4) selecting a carrier. Since CeO2-ZrO2Is helpful for the uniform dispersion of noble metal on the surface of the carrier, improves the utilization rate of active components and prevents Al2O3Sintering; at the same time due to La2O3The deep oxidation property of Pd catalyst can be improved and the dispersion of Ag can be promoted, so CeO is used as the material2-ZrO2-La2O3-Al2O3The prepared catalyst not only can deeply oxidize methanol but also greatly improves the low-temperature activity of the methanol by taking Pd and Ag as active components as carriers, which are not reported in previous researches.
2) Space velocity. The space velocity of the previous research system is generally not high (18000--1) The tail gas of the actual system has complex components and high space velocity (not less than 3 multiplied by 10)4h-1) The higher space velocity directly influences the contact time of the reaction gas and the catalyst, so that the reaction gas cannot be completely purified, the catalyst combines the practical situation, the catalytic performance of the catalyst is investigated at the high space velocity, and the method has very important guiding significance for the practical application of the catalyst.
3) The multifunctional properties of the catalyst. The prior research shows that the reaction system is single, most of the reaction system is methanol or a system of methanol and CO coexisting, the patent simulates the actual tail gas composition, and the main conventional pollutants of CO and NO in the tail gas are removedxHC and methanol which is an unconventional pollutant are also contained, so the catalyst developed by the patent is a multifunctional catalyst based on methanol catalytic purification.
4) Breakthrough of preparation technology. The introduction mode of the bimetal in the bimetal catalyst directly determines the type of the active center exposed on the surface of the catalyst and the strength of the interaction between the active component and the carrier, and the latter directly influences the flow performance of active oxygen on the catalyst.
The invention fully inspects the influence of the adding modes of the active components Pd and Ag in the bimetallic catalyst on the catalytic performance of methanol, and finds that the catalysts prepared by different adding modes have good catalytic activity on methanol.
Drawings
FIG. 1 is a graph showing the results of tests on the purification of unconventional pollutants by Pd-Ag catalysts prepared by three preparation methods;
FIG. 2 is a graph showing the results of CO purification tests of Pd-Ag catalysts prepared by three preparation methods;
FIG. 3 shows Pd-Ag catalyst pairs C prepared by three preparation methods3H8A test result graph of (1);
fig. 4 is a graph showing the results of the test for the purification of NO by the Pd-Ag catalyst prepared by the three preparation methods.
Wherein, (1) Ag/Pd/CZLA (2) Pd + Ag/CZLA (3) Pd/Ag/CZLA.
Detailed Description
A catalyst is prepared from Pd and Ag as active components and CeO2-ZrO2-La2O3-Al2O3The carrier is prepared by the following specific steps:
1) preparation of the carrier:
ZrO (CO) is added according to a certain stoichiometric ratio3)2Dissolving in concentrated nitric acid, and adding dissolved Ce (NO) in deionized water3)3.6H2O，La(NO3)3And Al (NO)3)3·9H2Mixing with O solution, adding NH3·H2Titrating O as a precipitator, controlling the pH value to be 8-10, aging after titrating, filtering, drying, and roasting the obtained powder at 600 ℃ for 5h to obtain a catalyst carrier, wherein the mol ratio of the components in the catalyst carrier is Ce: Zr: La: Al (1-10): 0.5-4): 3-30;
2) preparation of the catalyst:
weighing a certain mass of catalyst carrier, and preparing the catalyst according to different addition modes by adopting an equal pore volume impregnation method;
① adding Pd + Ag as catalyst, the preparation process comprises preparing Pd (NO) at a certain ratio3)2And AgNO3Adding a carrier of a certain mass into the aqueous solution mixture, and heating to 100 deg.CDrying and roasting at 500 ℃ to obtain Pd + Ag/CeO2-ZrO2-La2O3-Al2O3(abbreviated as Pd + Ag/CZLA) catalyst powder;
② adding Ag/Pd catalyst step by preparing Pd/CZLA, adding certain mass of carrier into Pd (NO)3)2Drying in water solution at 100 deg.C, calcining at 500 deg.C to obtain catalyst powder, and adding AgNO3Drying in water solution at 100 ℃, and roasting at 500 ℃ to obtain final catalyst powder Ag/Pd/CZLA;
③ adding Pd/Ag catalyst step by preparing Ag/CZLA, adding certain mass of carrier to AgNO3Drying in water solution at 100 deg.C, calcining at 500 deg.C to obtain catalyst powder, and adding into Pd (NO)3)2Drying in water solution at 100 deg.c and roasting at 500 deg.c to obtain the final catalyst powder Pd/Ag/CZLA.
The aging method comprises the following steps: after titration, adopting a water bath, an oil bath or a high-pressure reaction kettle, controlling the temperature to be 70-180 ℃ and the time to be 4-48h, and finishing aging.
The sum of the Pd and Ag contents in the catalyst powder is 1.0 wt% -2.0 wt%.
Another object of the present invention is to provide a catalyst prepared by the above method.
The invention further aims to provide application of the catalyst, which is to apply the catalyst to multifunctional methanol vehicle tail gas treatment.
The specific application method comprises the following steps: grinding the catalyst, coating the ground catalyst on a cordierite honeycomb ceramic substrate with the coating amount of 100-150g/L, drying, roasting, and then applying to multifunctional methanol vehicle tail gas treatment.
To evaluate the activity of the prepared catalyst, we performed activity evaluation.
The activity test was performed in a laboratory assembled multi-channel fixed bed continuous flow microreactor: the catalyst is directly loaded into the reactor, the temperature is programmed to carry out activity test, and each path of gas is metered into the mixer by a mass flow meter. The volume composition of the mixed gas is as follows: 0.02-0.03％CH3OH、2.0％O2、0.55％CO、810ppm C3H8、900-1000ppm NO、N2For balancing gas, the volume space velocity of the gas is 30000h-1-40000h-1. The organic gas components were analyzed on-line by gas chromatograph (GD-2000, Shanghai analytical Instrument factory), Porapak-Q packed column, FID detection, CO, NO and O2The five-component analyzer was used for detection (Guangdong Buddha).
The research results are as follows:
1) activity test result analysis
The catalysts prepared by different impregnation methods have different catalytic reaction rules. The results of the activity test are shown in FIGS. 1-4 and Table 1. The performance of the catalyst was evaluated using a light-off temperature T50 and a full conversion temperature T90, wherein T50 and T90 represent the reaction temperatures at which the conversion reached 50% and 90%, respectively.
TABLE 1 methanol, CO, C on catalyst3H8And T50 and T90 for NO conversion
As can be seen from fig. 1 and table 1, the three catalysts obtained by different preparation methods have better catalytic activity on methanol and CO, wherein the catalytic performance of Ag/Pd is best, T50 and T90 are lowest for methanol and CO, T50 is 167 ℃ (methanol) and 150 ℃ (CO) respectively, and 188 ℃ (methanol) and 187 ℃ (CO) for CO respectively, and Pd + Ag and Pd/Ag are second highest; however, at temperatures above 300 deg.C, both Pd + Ag and Ag/Pd have a different degree of downward tendency than C in the system, except that the catalytic performance of Pd/Ag on CO is essentially constant3H8And the light-off of NO. It is worth noting that the reduction of Pd + Ag is most significant, probably because the co-addition prepared Pd + Ag catalyst has fewer active centers on the surface and is susceptible to competitive adsorption of reaction molecules.
The difference is that the activity of Pd/Ag on NO increases and then decreases along with the increase of temperature, the highest conversion rate does not exceed 20 percent, and the possibility is that NO is activated and decomposed on an active site to generate O, but because the adsorption state of oxygen is strong in binding capacity with Pd, the adsorption state of oxygen is not easy to generate OAt this reaction temperature, desorption takes place, which in turn occupies the active sites on the surface suitable for the further decomposition of NO, and instead leads to methanol, CO and C3H8The higher conversion rate is maintained; it can be seen that since Ag and oxygen have a weak binding capacity and are easily removed, impregnation of Pd before impregnation of Ag is more favorable for desorption of O and promotion of NO conversion, whereas not so.
In conclusion, the preparation method of impregnating Pd first and then impregnating Ag (Ag/Pd) is more beneficial to the unconventional pollutants methanol and the conventional pollutants CO and C in the tail gas of the methanol gasoline vehicle3H8And NO purification, wherein T50 is 167 ℃, 150 ℃, 300 ℃ and 297 ℃ respectively, and NO by-product is generated.
2) Analysis of Activity influence mechanism
In order to further analyze the reason of the influence of the preparation method on the performance of the catalyst, an experimental subgroup carries out low-temperature N on the catalyst2Adsorption-desorption (BET), X-ray diffraction (XRD), H2Temperature programmed reduction (H)2TPR), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), and X-ray photoelectron spectroscopy (XPS).
a) According to the BET test result, the texture performance sequence of the three catalysts is as follows: pd + Ag > Ag/Pd > Pd/Ag, which is inconsistent with the activity test result, and the visible texture performance is not the main reason for influencing the activity;
b) XRD tests show that the unit cell parameters of three catalyst samples of Ag/Pd, Pd + Ag and Pd/Ag are 0.5304nm, 0.5310nm and 0.5300nm respectively, and the unit cell parameters are not changed greatly, which shows that the loaded metal ions of Pd and Ag are mainly distributed on the interface and the surface of the carrier;
c) reduction performance tests show that the reduction performance of the catalyst prepared by stepwise addition is obviously superior to that of the co-added catalyst, the co-addition mode can cause mutual coverage of active components, and the stepwise addition is more favorable for high dispersion of the active components, which has important significance for keeping higher catalytic activity of the catalyst; the reduction performance of Ag/Pd is superior to that of Pd/Ag, and the Pd-then-Ag preparation method enables the Ag and Pd metals to present different oxidation state forms on the surface of the Ag/Pd catalyst, so that active oxygen is increased, which is also an important reason for promoting the activity to be increased. The reduction performance sequence is Ag/Pd > Pd/Ag > Pd + Ag in sequence, and is consistent with the catalytic oxidation activity sequence;
d) in order to research the difference of different preparation methods on the interaction between double metals and the interaction between metals and carriers, X-ray photoelectron spectroscopy (XPS) analysis is carried out on three catalysts, and the difference of the preparation methods results in the difference of the interaction between the two metals Pd and Ag and the carriers and the change of the electronic environment between the two metals. For the Pd/Ag catalyst, the action between Ag and the carrier is tighter, so that oxygen (active oxygen) on the surface of the carrier is easier to flow to Ag, and the bonding capacity of Ag and oxygen is weaker, so that the active oxygen is rapidly bonded with Pd.
The Ag/Pd catalyst has Pd combined with CeO in the carrier more closely2There is a strong interaction, electron transfer can occur from Pd to Ce, thus leaving Pd in a higher oxidation state, and Ag is closer to a reduction state because of its weaker binding capacity to oxygen. The combination activity test shows that the Ag/Pd catalysis performance is best, namely the Pd is added firstly and then the Ag is added, so that the Pd species is in a higher oxidation state, the Ag species is in a lower reduction state, and the smooth catalytic reaction of the system is promoted.
By combining the analysis, the catalysts prepared by the three preparation methods have good catalytic activity on methanol, but the catalyst Pd-Ag/CZLA prepared by adding Pd and then Ag is more beneficial to the purification of conventional and unconventional pollutants in the tail gas of the methanol gasoline vehicle, so that a significant theoretical basis is provided for the further application and popularization of the methanol gasoline vehicle.
Claims (5)
1. A method for preparing a catalyst, which is characterized by comprising the following steps: pd and Ag are used as active components, CeO2-ZrO2-La2O3-Al2O3The carrier is prepared by the following specific steps:
1) preparation of the carrier:
ZrO (CO) is added according to a certain stoichiometric ratio3)2Dissolving in concentrated nitric acid, and adding dissolved Ce (NO) in deionized water3)3.6H2O，La(NO3)3And Al (NO)3)3·9H2Mixing with O solution, adding NH3·H2Titrating O as a precipitator, controlling the pH value to be 8-10, aging after titrating, filtering, drying, and roasting the obtained powder at 600 ℃ for 5h to obtain a catalyst carrier, wherein the mol ratio of the components in the catalyst carrier is Ce: Zr: La: Al (1-10): 0.5-4): 3-30;
2) preparation of the catalyst:
weighing a certain mass of catalyst carrier, and preparing the catalyst by adopting an equal pore volume impregnation method according to the following addition mode;
adding catalyst Ag/Pd step by step, the preparation process is as follows: firstly preparing Pd/CZLA, adding a certain mass of carrier into Pd (NO)3)2Drying in water solution at 100 deg.C, calcining at 500 deg.C to obtain catalyst powder, and adding AgNO3Drying in water solution at 100 ℃, and roasting at 500 ℃ to obtain final catalyst powder Ag/Pd/CZLA;
the aging method comprises the following steps: after titration, adopting a water bath, an oil bath or a high-pressure reaction kettle, controlling the temperature to be 70-180 ℃ and the time to be 4-48h, and finishing aging.
2. The method for preparing the catalyst according to claim 1, wherein: the sum of the Pd and Ag contents in the catalyst powder is 1.0 wt% -2.0 wt%.
3. A catalyst, characterized by: the catalyst is prepared by the method of claim 1 or 2.
4. The application of the catalyst in multifunctional methanol vehicle tail gas treatment is to apply the catalyst in claim 3.
5. Use of a catalyst according to claim 4, characterized in that: the catalyst is ground and then coated on a cordierite honeycomb ceramic matrix, the coating amount is 100-150g/L, and the catalyst is dried, roasted and then applied to the tail gas treatment of the multifunctional methanol vehicle.
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| CN109342642A (en) * | 2018-10-11 | 2019-02-15 | 成都信息工程大学 | A kind of measuring method of different carriers catalyst to methanol catalytic oxidation performance |
| CN109201053B (en) * | 2018-10-11 | 2021-11-05 | 成都信息工程大学 | Pd/CeO based on base metal doping2-Al2O3Catalyst and preparation method thereof |
| CN109589960B (en) * | 2018-11-09 | 2019-11-22 | 四川大学 | A kind of wall-flow type low precious metal content catalyst, preparation method and applications |
| CN109569597A (en) * | 2018-11-23 | 2019-04-05 | 成都信息工程大学 | A kind of modified Pd/BaCe catalyst and preparation method thereof |
| CN109569598B (en) * | 2018-11-23 | 2022-03-11 | 成都信息工程大学 | Pd/CeBaSi catalyst and preparation method thereof |
| CN116212944B (en) * | 2023-03-23 | 2023-09-22 | 北方稀土华凯高科技河北有限公司 | Lean-burn methanol fuel automobile exhaust purification catalyst and preparation method thereof |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101549301A (en) * | 2009-01-20 | 2009-10-07 | 昆明贵研催化剂有限责任公司 | Natural gas vehicle tai-gas clean-up catalyst and preparation method thereof |
| CN102553579A (en) * | 2011-05-27 | 2012-07-11 | 中国科学院福建物质结构研究所 | Preparation method of high-dispersity supported nano metal catalyst |
| CN103252242A (en) * | 2012-02-16 | 2013-08-21 | 中国石油化工股份有限公司 | Non-noble metal catalyst used for catalytic combustion of PTA exhaust gas and preparation method thereof |
| CN103447030A (en) * | 2013-08-27 | 2013-12-18 | 中国科学院过程工程研究所 | Preparation method of palladium-lead bimetallic catalyst with eggshell structure |
| CN104368339A (en) * | 2014-09-19 | 2015-02-25 | 哈尔滨工业大学深圳研究生院 | Catalyst for concurrently and efficiently removing soot and NOx under oxygen-enriched, sulfur-containing and water-containing conditions, and preparation method thereof |
| CN104785257A (en) * | 2015-04-02 | 2015-07-22 | 无锡威孚环保催化剂有限公司 | Single-coating three-way catalyst and preparation method thereof |
| CN105148908A (en) * | 2015-08-17 | 2015-12-16 | 四川中自尾气净化有限公司 | Preparation method and application of supported noble metal catalyst |
| CN105170149A (en) * | 2015-11-04 | 2015-12-23 | 浙江达峰汽车技术有限公司 | Preparation method for low precious metal catalyst for purifying motor vehicle exhaust |
-
2015
- 2015-12-28 CN CN201511000561.2A patent/CN105618043B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101549301A (en) * | 2009-01-20 | 2009-10-07 | 昆明贵研催化剂有限责任公司 | Natural gas vehicle tai-gas clean-up catalyst and preparation method thereof |
| CN102553579A (en) * | 2011-05-27 | 2012-07-11 | 中国科学院福建物质结构研究所 | Preparation method of high-dispersity supported nano metal catalyst |
| CN103252242A (en) * | 2012-02-16 | 2013-08-21 | 中国石油化工股份有限公司 | Non-noble metal catalyst used for catalytic combustion of PTA exhaust gas and preparation method thereof |
| CN103447030A (en) * | 2013-08-27 | 2013-12-18 | 中国科学院过程工程研究所 | Preparation method of palladium-lead bimetallic catalyst with eggshell structure |
| CN104368339A (en) * | 2014-09-19 | 2015-02-25 | 哈尔滨工业大学深圳研究生院 | Catalyst for concurrently and efficiently removing soot and NOx under oxygen-enriched, sulfur-containing and water-containing conditions, and preparation method thereof |
| CN104785257A (en) * | 2015-04-02 | 2015-07-22 | 无锡威孚环保催化剂有限公司 | Single-coating three-way catalyst and preparation method thereof |
| CN105148908A (en) * | 2015-08-17 | 2015-12-16 | 四川中自尾气净化有限公司 | Preparation method and application of supported noble metal catalyst |
| CN105170149A (en) * | 2015-11-04 | 2015-12-23 | 浙江达峰汽车技术有限公司 | Preparation method for low precious metal catalyst for purifying motor vehicle exhaust |
Non-Patent Citations (5)
| Title |
|---|
| "Ag对Pd/CeO2-ZrO2-La2O3-Al2O3催化氧化甲醇性能的影响";张雪乔等;《无机化学学报》;20120810;第28卷(第8期);第1563-1569页 * |
| "Ce-Zr-La-Al2O3的制备及负载的单Pd三效催化剂";蔡黎等;《催化学报》;20080215;第29卷(第2期);第108-112页 * |
| "钌系双贵金属催化同时去除碳颗粒和NOx的研究";何建昇;《中国优秀硕士学位论文全文数据库工程科技I辑》;20140115(第1期);B027-428 * |
| 张雪乔等."Ag对Pd/CeO2-ZrO2-La2O3-Al2O3催化氧化甲醇性能的影响".《无机化学学报》.2012,第28卷(第8期),第1563-1569页. * |
| 朱兵等."甲醇燃料车尾气净化催化剂的研究 Ⅲ.甲醇深度氧化用Ag-Pd/γ-Al2O3催化剂中Ag与Pd的协同作用".《催化学报》.1997,第18卷(第6期),第468-472页. * |
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