CN114870865A - Supported Pd-based bimetallic nano-catalyst for CO reduction of NO - Google Patents
Supported Pd-based bimetallic nano-catalyst for CO reduction of NO Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
- B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
- B01J23/8933—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals also combined with metals, or metal oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/894—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals also combined with metals, or metal oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with rare earths or actinides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8643—Removing mixtures of carbon monoxide or hydrocarbons and nitrogen oxides
- B01D53/8646—Simultaneous elimination of the components
- B01D53/865—Simultaneous elimination of the components characterised by a specific catalyst
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/204—Carbon monoxide
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Abstract
The invention relates to a Pd-based bimetallic nano-catalyst for reducing NO by CO and a preparation method thereof, wherein the catalyst is rod-shaped CeO 2 The carrier is prepared by taking PdCu bimetal as an active component and cerium nitrate, ethylene glycol, sodium tetrachloropalladate and sodium borohydride as raw materials. The catalyst has the advantages of good effect of catalyzing CO to reduce NO, simple preparation process, mild condition and low cost, and has important scientific significance and good application prospect.
Description
Technical Field
The invention relates to preparation of a supported Pd-based bimetallic nano-catalyst for catalyzing CO to reduce NO and application of the supported Pd-based bimetallic nano-catalyst in catalyzing CO to reduce NO, and belongs to the field of nano-material preparation and catalytic application.
Background
At present, the rapid development of economy accelerates the urbanization process of China, and the automobile holding amount is increased. Automobiles bring great environmental problems while bringing convenience to our lives. The automobile exhaust pollutant has relatively complicated components, and the main components of the automobile exhaust pollutant comprise carbon monoxide CO, hydrocarbon HC and nitrogen oxide NO x Solid suspended particulate PM, etc., and the air pollution caused by the pollutants is climate change and biodiversityLoss, economic and social development, traffic safety and public health. According to related departments, the NO discharged by every thousand cars in one day is counted x The mass is 100-160 kg, and the weight of CO is 4000-4500 kg. Wherein NO x （NO、NO 2 、N 2 O, etc.) can lead to acid rain, photochemical smog, greenhouse effects, ozone destruction, and the like. NO in motor vehicle exhaust pollutant NO x The highest content of NO is about 90% x Can be reacted with O 3 Reaction, which plays a major role in acid rain, which can cause death of organisms in lakes and rivers; NO x The light-chemical reaction is carried out with HC under the action of sunlight to form photochemical smog; n is a radical of 2 O can cause ozone destruction, forming ozone voids. CO can contribute to global warming; CO also affects plant respiration and nitrogen fixation. Therefore, it is urgent to control the environmental pollution caused by the emission of automobile exhaust, and it is important to develop a more efficient catalyst for purifying automobile exhaust in addition to making stricter laws and regulations and adjusting energy structure.
Nowadays, three-way catalysts (TWC) using noble metals platinum (Pt), rhodium (Rh) and palladium (Pd) as active components have been widely studied for automobile exhaust gas purification. The three-effect catalytic technology can simultaneously remove CO and NO in the tail gas x And conversion of HC to CO 2 、H 2 O and N 2 And is used as the most important external purifying technology in the automobile exhaust treatment system. There are many chemical reactions that take place over a three-way catalyst, the CO reduction NO reaction (2 CO +2NO = N) 2 +2CO 2 ) Is one of the key reactions, so the research usually adopts a CO reduction NO reaction model to simulate the actual working condition.
To achieve optimal conversion of pollutants, a three-way catalyst needs to approach the stoichiometric air-fuel ratio during the reaction. On the other hand, compared with the traditional catalyst, the supported nano noble metal catalyst has the excellent characteristics of small size of nano particles, large specific surface area, high surface activity and the like, and the nano heat is raised. Supports having a high specific surface area (the most common supports being metal oxides, such as SiO) 2 、Al 2 O 3 And CeO 2 ) Can be combined with metal particlesThe particles have sufficiently strong interactions. First, with SiO 2 And Al 2 O 3 Comparison of such inert carriers with CeO 2 The catalyst has good oxygen storage and release performance, is easy to switch between a reduction state and an oxidation state, is easy to form oxygen vacancies, and is equivalent to automatically adjusting the actual air-fuel ratio of a vehicle to stoichiometric balance, so that the noble metal can be recovered to a metal valence state with more catalytic activity under the stoichiometric condition, and the catalytic capability of the catalyst is ensured. Second, CeO 2 The shape is rich and controllable, the synthesis method is reliable, M-O-Ce bonds (M is noble metal) can be formed between the noble metal and the noble metal, the noble metal is anchored, the migration and agglomeration of the noble metal can be inhibited, and the noble metal in CeO is improved 2 To (3) dispersion of (a). In addition, M-O-Ce can inhibit the sintering of the noble metal, and the defect that the noble metal is easy to sinter and inactivate is relieved to a certain extent. CeO (CeO) 2 These unique properties make it an excellent carrier for the CO reduction NO reaction.
Noble metals are the most studied class of catalysts in the CO reduction of NO. Among them, Rh-based catalysts perform best in removing NO, but are rather expensive and have limited yield. Pd is the most abundant precious metal which can be used for automobile exhaust treatment at present, and is closer to Rh in certain properties, the reaction requirement conditions of Pd are lower, and Pd also has better anti-sintering performance than Pt and Rh. Therefore, Pd-based catalysts are considered to be a promising three-way catalyst.
Because the noble metal catalyst is expensive, scarce in resources, easy to sinter at high temperature and poor in sulfur resistance, the noble metal catalyst is modified. Transition metal elements have a special electron orbital structure, and d orbital electrons of the transition metal elements are not filled, so that valence change of the transition metal elements generally exists, and the valence change enables transition metal oxides to have extremely excellent redox performance. The alloy with transition metal can not only reduce the consumption of rare Pd, but also modify the electronic structure of Pd and improve the catalytic performance. For example, Cu element in transition metal + And Cu 2+ Two forms, so that the introduction of the Cu element is widely researched on the catalyst and shows catalysis to a certain extentAnd (4) performance. PdCu/CeO 2 Pd/CeO as compared with bimetallic supported catalyst 2 The single metal loaded noble metal catalyst has higher catalytic activity, lower cost and stronger poisoning resistance.
For the reasons, the invention carries the Pd and the Cu in the CeO in an alloying way 2 In the above, research and development of a supported Pd-based bimetallic nano-catalyst for CO reduction of NO have important economic and practical significance.
Disclosure of Invention
The invention aims to provide a supported Pd-based bimetallic nano-catalyst for CO reduction of NO.
The supported Pd-based bimetallic nano-catalyst for reducing NO by CO comprises the following preparation steps:
(1) 3 mmol of cerium nitrate (Ce (NO) was weighed 3 ) 3 ·6H 2 O) was dissolved in a volume of ultrapure water and stirred until completely dissolved, and was designated as solution I.
(2) Preparing 40mL of NaOH aqueous solution, dropwise adding the NaOH aqueous solution into the solution I, transferring the solution into a reaction kettle, sealing, preserving heat at 100 ℃ for 24 hours to perform hydrothermal reaction, and sequentially cleaning the reactants by using ultrapure water and absolute ethyl alcohol. Washing, drying the obtained precipitate at 60-70 deg.C for 8-12 h, and calcining at 300 deg.C in muffle furnace for 3h to obtain rod-shaped CeO 2 And (3) a carrier.
(3) Weighing a certain amount of Na 2 PdCl 4 And Cu (NO) 3 ) 2 Dissolved in Ethylene Glycol (EG) and stirred until completely dissolved, and recorded as solution II and solution III.
(4) Adding CeO 2 Grinding the carrier, adding into ethylene glycol, and treating with ultrasound for 30-60min to make the mixture uniformly mixed to be creamy yellow. Then, under the condition of continuous stirring, the solution II and the solution III are added dropwise in sequence, and the solution IV is marked.
(5) A2 mol/L NaOH/EG solution was added dropwise to solution IV to a pH =9-10, and then stirred at room temperature for 3h, as solution V.
(6) Adding a reducing agent into the solution V, and stirring at the constant temperature of 80 ℃ for 2 hours.
(7) And cleaning and drying the stirred solution to obtain the supported Pd-based bimetallic nano-material.
Compared with the prior art, the invention has the following substantial advantages:
the catalyst synthesized by the invention is a supported Pd-based bimetallic nano-catalyst for reducing NO by CO, can simultaneously remove two pollutants of CO and NO, and can be used for efficiently treating the problem of air pollution caused by automobile exhaust emission.
The catalyst synthesized by the invention has the characteristics of uniform particle distribution, small particle size and many oxygen vacancies.
The method is simple and easy to implement, mild in preparation conditions, and easy to obtain raw materials, and is an environment-friendly green synthetic catalyst.
Drawings
FIG. 1-FIG. 2 show PdCu/CeO prepared according to the present invention 2 And Pd/CeO 2 XRD pattern of catalyst.
FIGS. 3-4 show PdCu/CeO prepared according to the present invention 2 HRTEM of catalyst.
FIGS. 5 to 6 show Pd/CeO prepared by the present invention 2 HRTEM of catalyst.
FIG. 7 shows PdCu/CeO prepared according to the present invention 2 And Pd/CeO 2 ICP-OES results for the catalyst.
FIGS. 8-14 show PdCu/CeO prepared according to the present invention 2 And Pd/CeO 2 XPS spectra and related element content of the catalyst.
FIGS. 15-16 show PdCu/CeO prepared according to the present invention 2 And Pd/CeO 2 Catalytic CO reduction NO profile of the catalyst.
Detailed Description
The present invention will be further described with reference to the following specific examples.
Example one
(1) 3 mmol of cerium nitrate (Ce (NO) was weighed 3 ) 3 ·6H 2 O) was dissolved in 20 mL of ultrapure water and stirred until completely dissolved, and was designated as solution I.
(2) Preparing 40mL of 9 mol/L NaOH aqueous solution, and dropwise adding the solution IAnd transferring the solution into a reaction kettle, sealing, preserving heat at 100 ℃ for 24 hours to perform hydrothermal reaction, and sequentially cleaning reactants for 3 times by using ultrapure water and absolute ethyl alcohol. Washing, drying the obtained precipitate at 60 ℃ for 10 h, and calcining the precipitate in a muffle furnace at 300 ℃ for 3h to obtain CeO 2 And (3) a carrier.
(3) 1.35 mL of 10 g/L Na was weighed 2 PdCl 4 Dissolve in 5 mL Ethylene Glycol (EG) and stir until completely dissolved, as solution II. Weigh 0.006g of Cu (NO) 3 ) 2 ·3H 2 O was dissolved in 2 mL Ethylene Glycol (EG) and stirred until completely dissolved, as solution III.
(4) Weighing the synthesized CeO 2 0.25 g of the carrier was ground to fine particles and transferred to a beaker, and 40ml of leg was added and the mixture was mixed uniformly in a milky yellow color by sonication for 60 min. Then, while continuing to stir, solution II and solution III were added dropwise, and the solution was designated as solution IV.
(5) A2 mol/L NaOH/EG solution was added dropwise to solution IV to a pH =9-10, and then stirred at room temperature for 3h, as solution V.
(6) 10 mL of 4 mol/L NaBH 4 EG reducing agent is added into the solution V and then stirred for 2 hours at the constant temperature of 80 ℃.
(7) Centrifugally cleaning the stirred solution for 10 times by using ultrapure water, and drying at 100 ℃ for 2h to obtain the supported Pd-based bimetallic nano material PdCu/CeO 2 。
The corresponding XRD pattern is shown in figure 1. The detection by XRD shows that PdCu/CeO 2 The catalyst showed good CeO 2 Diffraction peaks, all characteristic peaks corresponding to face-centered cubic CeO of 28.3 ° (111), 32.6 ° (200), 47.2 ° (220), 55.9 ° (311), 58.8 ° (222), 69.0 ° (400), 76.1 ° (331), 78.5 ° (420) 2 Crystal (PDF # 43-1002). No CeO after loading PdCu bimetal 2 The crystal phase structure is changed, and no characteristic diffraction peaks of Pd and Pd oxides and Cu oxides are observed, probably because PdCu particles are small, have the size less than 5nm and are highly dispersed in CeO 2 A surface.
Example two
(1) Weighing 3mmol of cerium nitrate (Ce (NO) 3 ) 3 ·6H 2 O) was dissolved in 20 mL of ultrapure water and stirred until completely dissolved, and was designated as solution I.
(2) Preparing 40mL of 9 mol/L NaOH aqueous solution, dropwise adding the NaOH aqueous solution into the solution I, transferring the solution into a reaction kettle, sealing, preserving heat at 100 ℃ for 24 hours to perform hydrothermal reaction, and sequentially cleaning the reactants for 3 times by using ultrapure water and absolute ethyl alcohol. Washing, drying the obtained precipitate at 60 ℃ for 10 h, and calcining the precipitate in a muffle furnace at 300 ℃ for 3h to obtain CeO 2 And (3) a carrier.
(3) 1.35 mL of 10 g/L Na was weighed 2 PdCl 4 Dissolve in 5 mL Ethylene Glycol (EG) and stir until completely dissolved, as solution II.
(4) Weighing the synthesized CeO 2 0.25 g of carrier was ground to fine particles and transferred to a beaker, 40mL of EG was added and the mixture was mixed well by sonication for 60min to give a milky yellow color. Solution II was then added dropwise with continued stirring, and was recorded as solution III.
(5) A2 mol/L NaOH/EG solution was added dropwise to solution III to a pH =9-10, then stirred at room temperature for 3h, noted as solution IV.
(6) 10 mL of 4 mol/L NaBH 4 The EG reducing agent is added into the solution IV and then stirred for 2 hours at the constant temperature of 80 ℃.
(7) Centrifugally cleaning the stirred solution for 10 times by using ultrapure water, and drying the solution at 100 ℃ for 2 hours to obtain the supported Pd-based nano material Pd/CeO 2 。
The corresponding XRD pattern is shown in fig. 2. The Pd/CeO is detected by XRD 2 The catalyst showed good CeO 2 Diffraction peaks, all characteristic peaks corresponding to face-centered cubic CeO of 28.4 ° (111), 32.9 ° (200), 47.4 ° (220), 56.1 ° (311), 59.2 ° (222), 69.3 ° (400), 76.4 ° (331), 78.9 ° (420) 2 Crystal (PDF # 43-1002). No use of CeO after loading Pd 2 The crystal phase structure is changed, and no characteristic diffraction peak of Pd and Pd oxide is observed, probably because Pd particles are smaller, have the size less than 5nm and are highly dispersed in CeO 2 A surface.
Example three
PdCu/CeO 2 The HRTEM photographs are shown in FIGS. 3-4. HRTEM (high resolution transmission electron microscopy) discovery that the prepared supported Pd-based bimetallic nano material PdCu/CeO 2 In which Pd and Cu are successfully attached to CeO 2 The surface of the nano-rod. Also, PdCu/CeO 2 The metal particles formed after the reduction are not present in the form of Pd and Cu independently of each other, but form PdCu alloys. Pd/CeO 2 The HRTEM photographs of (A) are shown in FIGS. 5 to 6. Photograph showing Pd/CeO 2 The Pd in (1) is not present in an ionic state, but is present mainly in a metallic state. The PdCu alloy is formed of PdCu/CeO 2 Catalytic effect ratio Pd/CeO 2 One of the better reasons.
Example four
FIG. 7 shows PdCu/CeO prepared according to the present invention 2 And Pd/CeO 2 ICP-OES result of (1). The element contents of Pd and Cu of the catalyst were determined by ICP-OES, confirming the presence of Pd and Cu elements in the sample.
Example five
FIGS. 8-14 show Pd/CeO prepared by the present invention 2 And PdCu/CeO 2 XPS spectra of the catalyst.
(1) FIG. 8 shows PdCu/CeO 2 And Pd/CeO 2 XPS spectrum of catalyst O1s, FIG. 9 is Pd/CeO 2 And PdCu/CeO 2 The amount of oxygen adsorbed on the surface of the catalyst. According to Pd/CeO 2 And PdCu/CeO 2 XPS results of O1s of (a) revealed that: the binding energy at 529.4eV is attributed to lattice oxygen (O) Lat ) The binding energy at 531.6eV is attributed to surface adsorption of oxygen (O) ads ) 533.7eV is attributed to other weakly bound oxygen species (O) γ ) Such as adsorption of molecular water. And Pd/CeO 2 Compared with the prior art, the percentage of oxygen adsorbed on the surface of the sample loaded with the PdCu alloy is obviously increased, which shows that the PdCu bimetal generates a synergistic effect, and the generation of active adsorbed oxygen is promoted, so that the catalytic effect is better.
(2) FIG. 10 shows PdCu/CeO 2 And Pd/CeO 2 XPS spectrum of catalyst Ce3d, FIG. 11 is Pd/CeO 2 And PdCu/CeO 2 Ce of the catalyst 3+ Content and peak position. According to PdCu/CeO 2 And Pd/CeO 2 XPS result of Ce3d (supra) showsTo find out: and Pd/CeO 2 In contrast, sample Ce after loading PdCu 3+ The content of (c) increases. Ce 3+ Since Ce is generated to balance the charge generated due to oxygen vacancy 3+ Can represent the content of oxygen vacancies in the sample, i.e. PdCu/CeO 2 The oxygen vacancy content is increased, and the occurrence of catalytic reaction is promoted.
(3) FIG. 12 shows Pd/CeO 2 And PdCu/CeO 2 XPS spectrum of Pd3d catalyst, and FIG. 13 is Pd/CeO 2 And PdCu/CeO 2 Pd of the catalyst 0 Content and peak position. According to Pd/CeO 2 And PdCu/CeO 2 The XPS result of Pd3d of (a) can find that: CeO (CeO) 2 Pd and Cu are loaded simultaneously to form a PdCu alloy structure, electron transfer exists between alloy particles and a carrier, the interaction between the carrier and alloy ions is enhanced, the binding energy of Pd3d is deviated, and Pd is promoted 0 Formation of species, Pd 0 Is favorable for improving the catalytic activity.
(4) FIG. 14 shows PdCu/CeO 2 The Cu2p XPS spectrum of the catalyst confirms the existence of Cu element, and shows that the bimetal PdCu is successfully loaded on CeO 2 On a carrier.
Example six
The Pd-based bimetallic nano-catalyst and the Pd-based single metal nano-catalyst prepared in the first example and the second example are respectively used for the reaction of catalyzing and reducing NO by CO. Grinding the catalyst, screening out 40-80 mesh catalyst, filling the catalyst into a quartz tube with the diameter of 6mm, carrying out the experiment in a fixed bed reactor, wherein the reaction temperature is 25-250 ℃, and evaluating the activity of the catalyst by adopting a Temperature Programmed Oxidation (TPO) technology.
First at 5% H 2 Pretreating for 3 hours at 300 ℃ in Ar atmosphere, switching to CO + NO atmosphere after cooling to room temperature, carrying out temperature programming reaction, and detecting CO in tail gas after reaction by using a gas phase spectrometer x By NO x Analyzer for detecting NO in tail gas after reaction x The results of the experiment are shown in fig. 15 and 16. By comparing PdCu/CeO 2 And Pd/CeO 2 The CO conversion rate and the NO conversion rate of the two materials are found to be PdCu/CeO 2 The catalyst can realize 90 percent of NO conversion at 162 ℃ and realize NO conversion at 175 DEG C90% of CO conversion is achieved; and Pd/CeO 2 The catalyst can achieve 90% NO conversion at 219 ℃ and 90% CO conversion at 188 ℃. It can therefore be concluded that: in CeO 2 Catalysts with PdCu supported thereon, i.e. PdCu/CeO 2 The catalyst has good medium-low temperature activity, reduces the ignition temperature of the reaction of CO and NO, and obviously improves the capability of reducing NO by CO.
Claims (12)
1. A preparation method of a supported Pd-based bimetallic nano-catalyst for reducing NO by CO is characterized by comprising the following steps: the catalyst is CeO 2 As a carrier, PdCu is used as an active component, and a precursor of the active component is Na 2 PdCl 4 The Pd content was 1.63% by weight and the Cu content was 0.64% by weight of the carrier mass.
2. A method for preparing a supported Pd-based bimetallic nanocatalyst for CO reduction of NO as claimed in claim 1, characterized in that: the catalyst carrier CeO 2 The preparation method adopts a hydrothermal method, and comprises the following steps:
(1) 3 mmol of cerium nitrate (Ce (NO) was weighed 3 ) 3 ·6H 2 O) is dissolved in a certain amount of ultrapure water, stirred until the ultrapure water is completely dissolved, and is marked as a solution I;
(2) preparing 40mL of NaOH aqueous solution, dropwise adding the NaOH aqueous solution into the solution I, transferring the solution into a reaction kettle, sealing, preserving heat at 100 ℃ for 24 hours to perform hydrothermal reaction, and sequentially cleaning reactants by using ultrapure water and absolute ethyl alcohol;
(3) washing, drying the obtained precipitate at 60-70 deg.C for 8-12 h, and calcining at 300 deg.C in muffle furnace for 3h to obtain CeO 2 And (3) a carrier.
3. The method for preparing supported Pd-based bimetallic nanomaterial for CO reduction of NO according to claim 2, characterized in that: preparation of CeO 2 The solvent used in the carrier process is ultrapure water.
4. The method for preparing the supported Pd-based bimetallic nanomaterial as claimed in claim 2, characterized in that: in the step (1), the amount of ultrapure water was 20 mL.
5. The method for preparing the supported Pd-based bimetallic nanomaterial for CO reduction of NO as in claim 2, wherein: in the step (2), the concentration of the NaOH solution is 9 mol/L.
6. A method for preparing a supported Pd-based bimetallic nanocatalyst for CO reduction of NO as claimed in claim 1, characterized in that: the loading mode of the catalyst active component PdCu adopts a deposition precipitation method, and the method comprises the following steps:
(1) weighing a certain amount of Na 2 PdCl 4 And Cu (NO) 3 ) 2 Dissolving in Ethylene Glycol (EG), stirring until the solution is completely dissolved, and recording as a solution II and a solution III;
(2) adding CeO 2 Grinding the carrier, adding into ethylene glycol, treating with ultrasound for 30-60min to make the mixture uniformly mixed to be creamy yellow,
then under the state of continuous stirring, adding the solution II and the solution III dropwise in sequence, and marking as a solution IV;
(3) dropwise adding 2mol/L NaOH/EG solution into the solution III until the pH is =9-10, and then stirring for 3h at room temperature, and marking as a solution V;
(4) adding a reducing agent into the solution V, and stirring at the constant temperature of 80 ℃ for 2 hours;
(5) and cleaning and drying the stirred solution to obtain the supported Pd-based bimetallic nano-material.
7. The method for preparing the supported Pd-based bimetallic nanomaterial for CO reduction of NO according to claim 6, wherein: all solvents used in the process of loading the PdCu bimetal are ethylene glycol.
8. The method of claim 6 for preparing the supported Pd-based bimetallic nanomaterial for CO reduction of NOThe preparation method is characterized by comprising the following steps: in the step (1), Na 2 PdCl 4 And ethylene glycol in a volume ratio of 3: 10.
9. The method for preparing supported Pd-based bimetallic nanomaterial for CO reduction of NO according to claim 6, characterized in that: in the step (2), the amount of ethylene glycol was 40 mL.
10. The method for preparing supported Pd-based bimetallic nanomaterial for CO reduction of NO according to claim 6, characterized in that: the reducing agent in the step (4) is 4 mol/L NaBH 4 The ratio of the amount of reducing agent to Pd in the EG solution was 1000: 1.
11. The preparation method of the supported Pd-based bimetallic nanomaterial for CO reduction of NO according to claim 6, characterized in that: in the step (5), the cleaning method and times are 10 centrifugal washing with ultrapure water; the drying temperature is 100-120 ℃, and the drying time is 2-4 h.
12. The preparation method of the supported Pd-based bimetallic nanomaterial for CO reduction of NO according to claim 6, characterized in that: the prepared catalyst has high-activity low-temperature CO reduction NO catalytic capability.
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| US20080233039A1 (en) * | 2005-06-02 | 2008-09-25 | Symyx Technologies, Inc. | Catalysts For Co Oxidation,Voc Combustion And Nox Reduction And Methods Of Making And Using The Same |
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| US20080233039A1 (en) * | 2005-06-02 | 2008-09-25 | Symyx Technologies, Inc. | Catalysts For Co Oxidation,Voc Combustion And Nox Reduction And Methods Of Making And Using The Same |
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