CN109794241B - Cerium oxide selective coating supported palladium catalyst and preparation method thereof - Google Patents
Cerium oxide selective coating supported palladium catalyst and preparation method thereof Download PDFInfo
- Publication number
- CN109794241B CN109794241B CN201910076565.0A CN201910076565A CN109794241B CN 109794241 B CN109794241 B CN 109794241B CN 201910076565 A CN201910076565 A CN 201910076565A CN 109794241 B CN109794241 B CN 109794241B
- Authority
- CN
- China
- Prior art keywords
- catalyst
- solution
- supported
- preparation
- cerium oxide
- 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.)
- Active
Links
Images
Abstract
The invention provides a cerium oxide selectively-coated supported palladium catalyst and a preparation method thereof, relates to the technical field of precious metal catalysis, and provides a preparation method of a cerium oxide selectively-coated supported palladium catalyst, which comprises the following steps: Pd/Al2O3And mixing the supported catalyst, L-arginine, cerium nitrate and a solvent, and sequentially coating and roasting to obtain the cerium oxide selectively-coated supported palladium catalyst. The cerium oxide selective-coated supported palladium catalyst prepared by the preparation method has good low-temperature activity and excellent high-temperature thermal stability.
Description
Technical Field
The invention relates to the technical field of noble metal supported catalysts, in particular to a cerium oxide selectively-coated supported palladium catalyst and a preparation method thereof.
Background
With the rapid development of the economy of China and the continuous improvement of the travel demand of people, the rapid development of the automobile industry of China leads to the rapid increase of the number of motor vehicles, the automobile holding amount is continuously increased, and the problem of pollution emission of mobile sources of China is increasingly prominent. The existing catalytic purification technology is the most effective method for reducing the emission of automobile exhaust, and the noble metals of Pt, Rh and Pd show excellent catalytic activity in the catalytic reaction of the automobile exhaust, and are active components of a three-way catalyst for a motor vehicle. However, the precious metal resources are increasingly exhausted and the price is increasingly increased, and the precious metal reduction technology is a great challenge in the automobile catalyst industry. The development of nanocatalysis greatly improves the catalytic efficiency of the catalyst. However, the noble metal nano-catalyst has poor thermal stability, so that the noble metal nano-particles are easy to sinter and deactivate in the catalytic reaction process, and the industrial application of the noble metal nano-catalyst is seriously influenced. The working temperature of the existing vehicle catalyst can reach more than 800 ℃, and obviously, the noble metal nano particles can be seriously sintered and inactivated in the using process, so that the improvement of the thermal stability of the noble metal catalyst is one of the main problems at present.
At present, the three-way catalyst is mainly a supported three-way catalyst, the thermal stability of the noble metal nanoparticles seriously affects the catalytic activity of the catalyst, a series of works are carried out by many researchers around how to improve the thermal stability of the noble metal nanoparticles, and the method for widely researching at present is to wrap the noble metal nanoparticles with oxides to improve the high-temperature thermal stability of the catalyst. Louis et Al (science,2012,335(6073)1205-1208) Al-deposition on catalyst monoliths using atomic layer deposition2O3Coating, when performing 45 circles of Al2O3After deposition and wrapping, the catalyst reacts for 28 hours at 675 ℃, the morphology and the activity of the catalyst are not obviously changed, and the condition that the nano particles are sintered when the catalyst is applied at high temperature can be effectively prevented; atomic layer deposition of Al on ovarian cyst courage et Al (chem. Eur. J.2016,22,8438-2O3ALD Al of confined Pt nanoparticles2O3The thin layer modification maximizes the metal-oxide interface, not only improving the catalytic activity of the catalyst, but also improving its stability to a certain extent. However, the atomic layer deposition process requires special equipment, and the precursor for deposition is expensive, so that the catalyst cannot be treated in a large scale, and therefore, the atomic layer deposition process is not suitable for practical application.
Disclosure of Invention
The invention aims to provide a method for preparing a cerium oxide selectively-coated supported palladium catalyst, which has the advantages of simple operation process, good high-temperature resistance effect and low cost.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of a cerium oxide selectively-coated supported palladium catalyst, which comprises the following steps:
Pd/Al2O3Mixing the supported catalyst, L-arginine, cerium nitrate and a solvent, and sequentially coating and roasting to obtain the cerium oxide selectively-coated negativeA supported palladium catalyst.
Preferably, the Pd/Al2O3The load amount of Pd in the supported catalyst is 0.5wt% -5 wt%.
Preferably, the Pd/Al2O3The molar ratio of Pd to the cerium nitrate in the supported catalyst is 1: (10-30).
Preferably, the molar ratio of the L-arginine to the cerium nitrate is (2.5-10): 1.
preferably, the coating temperature is 60-100 ℃, and the coating time is 8-24 h.
Preferably, the roasting temperature is 500-900 ℃, and the roasting time is 2-8 h.
In the invention, the solvent is preferably deionized water or/and a mixed solution of ethanol;
preferably, the Pd/Al2O3The preparation method of the supported catalyst comprises the following steps:
mixing polyvinyl alcohol solution and Na2PdCl4Solution and NaBH4Mixing the solutions, and carrying out reduction reaction to obtain a product system containing Pd nanoparticles;
the product system containing Pd nano-particles and a carrier Al2O3Mixing and impregnating to obtain Pd/Al2O3A supported catalyst.
Preferably, the Na is2PdCl4Na in solution2PdCl4The mass ratio of the polyvinyl alcohol to polyvinyl alcohol in the polyvinyl alcohol solution is (2-3): (4-6);
the Na is2PdCl4Na in solution2PdCl4With NaBH4NaBH in solution4In a molar ratio of 1: (4-6).
Preferably, the dipping temperature is 20-40 ℃, and the dipping time is 10-20 h.
The invention also provides a cerium oxide selectively-coated supported palladium catalyst prepared by the preparation method of the technical scheme, which comprises Al2O3And supported on said Al2O3Pd nanoparticles and CeO on a support2；
The CeO2Selectively coating on the surface of the Pd nano-particles.
The invention provides a preparation method of a cerium oxide selectively-coated supported palladium catalyst, which comprises the following steps: Pd/Al2O3And mixing the supported catalyst, L-arginine, cerium nitrate and a solvent, and sequentially coating and roasting to obtain the cerium oxide selectively-coated supported palladium catalyst. The cerium oxide in the present invention is an active carrier material having excellent hydrogen storage and release capacity due to its two valence states, Ce is in different conditions4+And Ce3+Can be converted to each other. Under the condition of oxygen enrichment, the cerium oxide can absorb redundant oxygen; under the condition of dilute oxygen, oxygen can be released, and pollutants in the automobile exhaust can be effectively eliminated after the selective coating of the supported palladium catalyst. The L-arginine is an amphoteric substance, two ends of a molecule of the L-arginine are respectively provided with a guanidyl group and a carboxyl group, wherein an amino group in the guanidyl group has a lone pair of electrons, Pd has an electron empty orbit, and the guanidyl group can be coordinated with Pd; while carboxyl is dissolved in water and has electronegativity, and Ce3+The ions have positive electricity and can generate complexation to carry out carboxyl and Ce3+Due to the special structure of L-arginine, the precious metal is selectively coated by inducing cerium oxide by utilizing the L-arginine, so that the precious metal-oxide interface can be enlarged by selectively coating the precious metal by utilizing the cerium oxide to improve the catalytic activity, and the sintering resistance of the supported catalyst can be improved, thereby improving the thermal stability of the precious metal supported catalyst.
Drawings
FIG. 1 shows the triple-effect activity of 1#, 2#, 3# catalyst samples on CO at different temperatures;
FIG. 2 shows the three-way activity of 1#, 2#, 3# catalyst samples on HC at different temperatures;
FIG. 3 shows NO at different temperatures for 1#, 2#, and 3# catalyst samplesxThe triple-effect activity of (1);
FIG. 4 shows the triple-effect activity of 4#, 5#, 6# catalyst samples on CO at different temperatures;
FIG. 5 shows the three-way activity of 4#, 5#, 6# catalyst samples on HC at different temperatures;
FIG. 6 shows NO at different temperatures for 4#, 5#, 6# catalyst samplesxThe triple-effect activity of (1);
FIG. 7 is an XRD pattern of catalyst samples # 1#, # 2#, # 3#, # 4# and # 6;
FIG. 8 is a TEM image of a sample of catalyst # 1;
FIG. 9 is a TEM image of catalyst sample # 2;
FIG. 10 is a TEM image of catalyst sample # 3;
FIG. 11 is a TEM image of catalyst sample # 4;
FIG. 12 is a TEM image of a 5# catalyst sample;
fig. 13 is a TEM image of the catalyst sample # 6.
Detailed Description
The invention provides a preparation method of a cerium oxide selectively-coated supported palladium catalyst, which comprises the following steps:
Pd/Al2O3And mixing the supported catalyst, L-arginine, cerium nitrate and a solvent, and sequentially coating and roasting to obtain the cerium oxide selectively-coated supported palladium catalyst.
In the present invention, all the raw material components are commercially available products well known to those skilled in the art unless otherwise specified.
The invention uses Pd/Al2O3And mixing the supported catalyst, L-arginine, cerium nitrate and a solvent, and sequentially coating and roasting to obtain the cerium oxide selectively-coated supported palladium catalyst. In the present invention, the Pd/Al2O3The loading amount of Pd in the supported catalyst is preferably 0.5wt% to 5wt%, more preferably 1.0 wt% to 3.0 wt%, and most preferably 1.5 wt% to 2.5 wt%.
In the present invention, the Pd/Al2O3The process for the preparation of the supported catalyst preferably comprises the steps of:
mixing polyvinyl alcohol solution and Na2PdCl4Solution and NaBH4Mixing the solutions, and performing reduction reaction to obtain product containing Pd nanoparticlesAn article system;
the product system containing Pd nano-particles and a carrier Al2O3Mixing and impregnating to obtain Pd/Al2O3A supported catalyst.
In the invention, polyvinyl alcohol solution and Na are mixed2PdCl4Solution and NaBH4The solutions are mixed and subjected to reduction reaction to obtain a product system containing Pd nano particles. In the invention, the concentration of the polyvinyl alcohol solution is preferably 1.5-2.5 g/L, and more preferably 1.8-2.2 g/L; in the present invention, the solvent of the polyvinyl alcohol solution is preferably deionized water. In the present invention, the Na is2PdCl4The concentration of the solution is preferably 0.008-0.012 mol/L, and more preferably 0.009-0.011 mol/L; in the present invention, the Na is2PdCl4The solvent of the solution is preferably deionized water. In the present invention, the NaBH4The concentration of the solution is preferably 1.5-2.5 g/L, and more preferably 1.8-2.2 g/L; the NaBH4The solvent of the solution is preferably deionized water.
In the present invention, the Na is2PdCl4Na in solution2PdCl4The mass ratio of the polyvinyl alcohol to the polyvinyl alcohol in the polyvinyl alcohol solution is preferably (2-3): (4-6), more preferably (2.2-2.8): (4.5-5.5), most preferably (2.4-2.6): (4.8-5.2); the Na is2PdCl4Na in solution2PdCl4With NaBH4NaBH in solution4Is preferably 1: (4-6), more preferably 1: (4.5 to 5.5), most preferably 1: (4.8-5.2).
In the present invention, the mixing is preferably performed under the conditions of an ice-water bath and stirring; the stirring is not particularly limited in the present invention, and may be carried out by a stirring process known to those skilled in the art.
In the present invention, the polyvinyl alcohol solution and Na2PdCl4Solution and NaBH4The solution is preferably mixed by mixing a polyvinyl alcohol solution with Na2PdCl4After the solution is stirred and mixed for 15-25 min, quickly adding NaBH into the obtained mixed system under the stirring condition4And (3) solution. In thatIn the present invention, the NaBH is4The solution is preferably added by rapid pouring as is well known to those skilled in the art.
In the present invention, the mixing is preferably performed under the conditions of an ice-water bath; in the present invention, in the polyvinyl alcohol solution and Na2PdCl4Adding NaBH into the mixed solution quickly4The reduction reaction can be rapidly completed after the solution is dissolved, namely in polyvinyl alcohol solution and Na2PdCl4Adding NaBH into the mixed solution quickly4After the solution, the formation of a large amount of Pd particles in the product system was rapidly observed.
After a product system containing Pd nano-particles is obtained, the product system containing Pd nano-particles and a carrier Al are mixed2O3Mixing and impregnating to obtain Pd/Al2O3A supported catalyst; the invention is directed to the carrier Al2O3The amount of the catalyst is not particularly limited, and is such that the obtained Pd/Al alloy is obtained2O3The load amount of Pd in the supported catalyst is within the range of 0.5wt% -5 wt%.
In the present invention, the impregnation is preferably performed under stirring, and the stirring is not particularly limited in the present invention, and may be performed by a stirring process well known to those skilled in the art.
In the invention, the dipping temperature is preferably 20-40 ℃, more preferably 25-35 ℃, and most preferably 28-32 ℃; the soaking time is preferably 10-20 h, more preferably 12-18 h, and most preferably 14-16 h.
After the impregnation is finished, the Pd/Al is obtained by filtering and drying the obtained product system in sequence2O3A supported catalyst; the present invention does not have any particular limitation on the filtration, and filtration known to those skilled in the art may be employed; in the invention, the drying temperature is preferably 100-120 ℃, and more preferably 105-115 ℃; the drying time is not subject to any particular limitation in the present invention, and drying times known to those skilled in the art can be used to completely remove the water from the solid obtained by filtration, i.e., to remove the water completelyCan be prepared.
The Pd/Al2O3The mixture of the supported catalyst, the L-arginine, the cerium nitrate and the solvent is preferably Pd/Al2O3Mixing a supported catalyst, water, an L-arginine solution and a cerium nitrate solution; the solvent of the L-arginine solution is preferably deionized water; the concentration of the L-arginine solution is preferably 0.4-1.0 mol/L, and more preferably 0.6-0.8 mol/L. In the present invention, the solvent of the cerium nitrate solution is preferably a mixed solution of water and ethanol; the volume ratio of water to ethanol in the mixed liquid of water and ethanol is preferably 1: 1; the concentration of the cerium nitrate solution is preferably 0.03-0.06 mol/L, and more preferably 0.04-0.05 mol/L.
In the present invention, the Pd/Al2O3The volume ratio of the mass of the supported catalyst to the water is preferably (0.8-1.0) g: (25-35) mL, more preferably (0.85-0.95) g: (28-32) mL.
In the present invention, the Pd/Al2O3The molar ratio of Pd in the supported catalyst to cerium nitrate in the cerium nitrate solution is preferably 1 (10-30), more preferably 1 (15-25), and most preferably 1: (18-22).
In the invention, the molar ratio of the L-arginine in the L-arginine solution to the cerium nitrate in the cerium nitrate solution is preferably (2.5-10): 1, more preferably (4-8): 1, and most preferably (5-6): 1.
In the present invention, the Pd/Al2O3The mixing of the supported catalyst, water, the L-arginine solution and the cerium nitrate solution is preferably carried out at room temperature; the mixing is preferably: Pd/Al2O3Mixing the supported catalyst and water to obtain Pd/Al2O3After dispersion of the supported catalyst; then the Pd/Al is added2O3The dispersion of the supported catalyst was mixed with an L-arginine solution and a cerium nitrate solution in this order.
The invention is to the Pd/Al2O3The mixing of the supported catalyst and water is not particularly limited, and is carried out by a mixing process well known to those skilled in the art and the Pd/Al obtained after mixing2O3The supported catalyst dispersion is uniformly dispersed.
In the present invention, the Pd/Al2O3Mixing the dispersion liquid of the supported catalyst and the L-arginine solution preferably under stirring; in the invention, the stirring time is preferably 30-50 min, more preferably 35-45 min, and most preferably 38-42 min; the stirring rate is not particularly limited in the present invention, and the stirring may be performed at a stirring rate known to those skilled in the art.
In the present invention, the mixing with the cerium nitrate solution is preferably performed under stirring; in the invention, the stirring time is preferably 20-40 min, more preferably 25-35 min, and most preferably 28-32 min; the stirring rate is not particularly limited in the present invention, and the stirring may be performed at a stirring rate known to those skilled in the art.
In the invention, the coating temperature is preferably 60-100 ℃, more preferably 70-90 ℃, and most preferably 75-85 ℃; the coating time is preferably 8-24 hours, and more preferably 15-20 hours.
After the coating is finished, the obtained product system is preferably sequentially filtered, washed and dried; the filtration is not particularly limited in the present invention, and may be performed by a filtration process known to those skilled in the art.
In the present invention, the washing is preferably performed by sequentially using deionized water and ethanol.
In the invention, the drying temperature is preferably 100-120 ℃, and more preferably 105-115 ℃; the drying time in the present invention is not particularly limited, and may be any drying time known to those skilled in the art.
In the present invention, the calcination is preferably performed in an air atmosphere; the roasting temperature is preferably 500-900 ℃, more preferably 750-850 ℃ and most preferably 780-820 ℃; the roasting time is preferably 2-8 hours, and more preferably 3-5 hours.
The invention also provides the cerium oxide selective bag prepared by the preparation method of the technical schemeA supported palladium catalyst comprising Al2O3And supported on said Al2O3Pd nanoparticles and CeO on a support2；
The CeO2Coating on the surface of the Pd nano-particles; the load capacity of the Pd is 0.5-2.5 wt%; the CeO2The mass fraction of the cerium oxide selectively-coated supported palladium catalyst is 5.4-47.8%.
The cerium oxide selectively coated supported palladium catalyst and the preparation method thereof according to the present invention will be described in detail with reference to the following examples, which should not be construed as limiting the scope of the present invention.
Example 1
In an ice-water bath with stirring according to Na2PdCl4The weight ratio of the polyvinyl alcohol to the polyvinyl alcohol is 2.76:1.5, and the polyvinyl alcohol solution with the concentration of 2g/L and the Na with the concentration of 0.01mol/L are mixed2PdCl4After the solution was mixed for 20min, NaBH was added rapidly at a concentration of 2g/L4Solution (according to Na)2PdCl4With NaBH4The molar ratio of 1: 5) to generate a large amount of Pd nanoparticles to obtain a product system containing the Pd nanoparticles;
according to Na2PdCl4Mass of Pd in solution and Al2O3The mass ratio of (A) to (B) is 1.23:98.77, mixing Al2O3Adding into a product system containing Pd nanoparticles, stirring at 30 deg.C for 12h, filtering, and drying at 120 deg.C to obtain Pd/Al2O3A supported catalyst;
0.9g of Pd/Al2O3Mixing the supported catalyst with 30mL of water, uniformly dispersing, adding 10mL of L-arginine solution with the concentration of 0.42mol/L, stirring for 40min, adding 40mL of cerium nitrate solution with the concentration of 0.03mol/L, stirring for 30min, coating at 90 ℃ for 20h, washing with deionized water and ethanol in sequence, drying at 120 ℃, roasting at 500 ℃ for 3h to obtain the cerium oxide selectively-coated supported palladium catalyst, wherein the loading amount of the noble metal Pd is 1%. Denoted as catalyst # 2.
Example 2
In an ice-water bath with stirring according to Na2PdCl4The weight ratio of the polyvinyl alcohol to the polyvinyl alcohol is 2.76:1.5, and the polyvinyl alcohol solution with the concentration of 2g/L and the Na with the concentration of 0.01mol/L are mixed2PdCl4After the solution was mixed for 20min, NaBH was added rapidly at a concentration of 2g/L4Solution (according to Na)2PdCl4With NaBH4The molar ratio of 1: 5) to generate a large amount of Pd nanoparticles to obtain a product system containing the Pd nanoparticles;
according to Na2PdCl4Mass of Pd in solution and Al2O3The mass ratio of (A) to (B) is 1.46:98.54, mixing Al2O3Adding into a product system containing Pd nanoparticles, stirring at 35 deg.C for 12h, filtering, and drying at 120 deg.C to obtain Pd/Al2O3A supported catalyst;
0.9g of Pd/Al2O3Mixing the supported catalyst with 30mL of water, uniformly dispersing, adding 10mL of L-arginine solution with the concentration of 0.84mol/L, stirring for 40min, adding 40mL of cerium nitrate solution with the concentration of 0.06mol/L, stirring for 30min, performing coating reaction at 90 ℃ for 20h, washing with deionized water and ethanol in sequence, drying at 120 ℃, roasting at 500 ℃ for 3h to obtain the cerium oxide selectively-coated supported palladium catalyst, wherein the loading amount of the noble metal Pd is 1%. Denoted as catalyst # 3.
Comparative example 1
In an ice-water bath with stirring according to Na2PdCl4The weight ratio of the polyvinyl alcohol to the polyvinyl alcohol is 2.76:1.5, and the polyvinyl alcohol solution with the concentration of 2g/L and the Na with the concentration of 0.01mol/L are mixed2PdCl4After the solution was mixed for 20min, NaBH was added rapidly at a concentration of 2g/L4Solution (according to Na)2PdCl4With NaBH4The molar ratio of 1: 5) to generate a large amount of Pd nanoparticles to obtain a product system containing the Pd nanoparticles;
according to Na2PdCl4Mass of Pd in solution and Al2O3In a mass ratio of 1:99, adding Al2O3Adding into product system containing Pd nanoparticles, stirring at 30 deg.C for 12 hr, filtering, drying at 120 deg.C, and calcining at 500 deg.C for 3 hr to obtain Pd/Al2O3The supported catalyst, designated as catalyst # 1.
Example 3
Roasting part of the No. 1 catalyst sample obtained in the comparative example 1 at 900 ℃ for 5h in an air atmosphere, and cooling to room temperature to obtain an aged sample of the No. 1 catalyst, which is recorded as a No. 4 catalyst sample;
roasting part of the No. 2 catalyst sample obtained in the example 1 at 900 ℃ for 5 hours in an air atmosphere, and cooling to room temperature to obtain an aged sample of the No. 2 catalyst, which is recorded as a No. 5 catalyst sample;
roasting part of the No. 3 supported catalyst sample obtained in the example 2 at 900 ℃ for 5 hours in an air atmosphere, and cooling to room temperature to obtain an aged sample of the No. 3 catalyst, which is recorded as a No. 6 catalyst sample;
carrying out three-way catalytic activity evaluation tests on the 1#, 2#, 3#, 4#, 5# and 6# catalyst samples; the composition of the reaction gas is: 1.6% CO, 0.23% H2，500ppm HC(C3H8/C3H6＝2/1)，1000ppm NOx，1.0％O2，N2The gas flow is balance gas, and the gas flow is V-1000 mL/min;
FIG. 1 shows the triple-effect activity of 1#, 2#, 3# catalyst samples on CO at different temperatures; FIG. 2 shows the three-way activity of 1#, 2#, 3# catalyst samples on HC at different temperatures; FIG. 3 shows NO at different temperatures for 1#, 2#, and 3# catalyst samplesxThe triple-effect activity of (1); as can be seen from FIGS. 1 to 3, the samples of No. 1 catalyst contained CO, HC and NOxThe complete conversion temperatures of (A) are 219 ℃, 276 ℃ and 220 ℃ respectively; CO, HC, and NO for sample # 2 catalystxThe complete conversion temperatures of (A) are 177 ℃, 234 ℃ and 179 ℃ respectively; CO, HC, and NO for the #3 catalyst samplexThe complete conversion temperatures of (A) are 180 ℃, 256 ℃ and 198 ℃ respectively; the three-way catalytic activity of the catalyst sample obtained in the examples 1-2 is far better than that of the comparative example 1, which shows that the preparation method provided by the invention has better low-temperature catalytic activity than that of the comparative example;
FIG. 4 shows catalysts No. 4, No. 5 and No. 6Triple effect activity of the sample on CO at different temperatures; FIG. 5 shows the three-way activity of 4#, 5#, 6# catalyst samples on HC at different temperatures; FIG. 6 shows NO at different temperatures for 4#, 5#, 6# catalyst samplesxThe triple-effect activity of (1); as can be seen from FIGS. 4 to 6, the samples of the 4# catalyst include CO, HC, and NOxThe complete conversion temperatures of (A) are 255 ℃, 380 ℃ and 358 ℃ respectively; CO, HC, and NO for the 5# catalyst samplexThe complete conversion temperatures of (A) were 218 deg.C, 276 deg.C and 219 deg.C, respectively; CO, HC, and NO for the 6# catalyst samplexThe complete conversion temperatures of 198 ℃, 253 ℃ and 199 ℃ respectively; the aged three-way catalytic activity of the catalyst samples obtained in the embodiments 1 to 2 is far better than that of the aged three-way catalytic activity of the comparative example 1, which shows that the preparation method provided by the invention has better high-temperature stability compared with the comparative example, and the activity of the catalyst samples obtained in the embodiments 1 and 2 before and after aging is basically not changed greatly, so that the catalyst samples obtained by the preparation method provided by the invention not only have better low-temperature activity, but also have better high-temperature thermal stability.
Example 4
Carrying out phase structure analysis on the 1#, 2#, 3#, 4#, 5#, and 6# catalyst samples by adopting X-ray powder diffraction;
FIG. 7 is an XRD pattern of catalyst samples # 1#, # 2#, # 3#, # 4#, # 5#, and # 6; as can be seen from FIG. 7, Al in the sample2O3The main diffraction peaks are attributed to orthorhombic and tetragonal Al2O3(JCPDS PDF #46-1215 and PDF #16-0394), CeO2The oxides are attributed to a cubic phase structure (JCPDS PDF # 34-0394). No PdO phase is detected in the No. 1, No. 3 and No. 5 catalyst samples; only the No. 2 sample in the aged No. 2, No. 4 and No. 6 samples detects the existence of PdO phase, which shows that the No. 1 catalyst sample is sintered by noble metal after being subjected to high-temperature treatment; and No PdO phase is detected in the samples No. 4 and No. 6, which shows that the noble metal is still well dispersed, and sintering of the noble metal does not occur, thus the method greatly improves the thermal stability of the catalyst.
Example 5
Using transmission electron microscope to sample 1#, 2#, 3#, 4#, 5#, 6# catalystsPerforming TEM representation; FIGS. 8 to 13 are TEM images of No. 1, No. 2, No. 3, No. 4, No. 5 and No. 6 catalyst samples, respectively, and it can be seen from the TEM images that the particle size of the Pd nanoparticles in the No. 1 catalyst sample prepared in comparative example 1 is about 3 to 4nm, and the Pd nanoparticles in the No. 4 catalyst sample after aging have obvious aggregation growth phenomenon; example 1 preparation of CeO from sample of catalyst # 22Oxide particles cover the surface of the Pd catalyst, and the aged 5# catalyst sample has a redispersion phenomenon, which shows that the noble metal in the aged catalyst still has high dispersion degree and does not have a sintering phenomenon of the noble metal; example 2 preparation of CeO from sample of No. 3 catalyst2The oxide particles cover the surface of the Pd catalyst, and the re-dispersion phenomenon occurs in the aged No. 6 catalyst sample, which shows that the noble metal in the aged catalyst still has high dispersion degree, and the sintering phenomenon of the noble metal does not occur.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (7)
1. A preparation method of a cerium oxide selective coating supported palladium catalyst comprises the following steps:
Pd/Al2O3Mixing a supported catalyst, L-arginine, cerium nitrate and a solvent, and sequentially coating and roasting to obtain a cerium oxide selectively-coated supported palladium catalyst;
the cerium oxide selective coating supported palladium catalyst comprises Al2O3And supported on said Al2O3Pd nanoparticles and CeO on a support2(ii) a The CeO2Selectively coating the surface of the Pd nano-particles;
the Pd/Al2O3The molar ratio of Pd to the cerium nitrate in the supported catalyst is 1: (10-30);
the molar ratio of the L-arginine to the cerium nitrate is (2.5-10): 1;
the coating temperature is 60-100 ℃, and the coating time is 8-24 h.
2. The method of claim 1, wherein the Pd/Al is2O3The load amount of Pd in the supported catalyst is 0.5-5 wt%.
3. The preparation method according to claim 1, wherein the roasting temperature is 500-900 ℃, and the roasting time is 2-8 h.
4. The method of claim 1, wherein the Pd/Al is2O3The preparation method of the supported catalyst comprises the following steps:
mixing polyvinyl alcohol solution and Na2PdCl4Solution and NaBH4Mixing the solutions, and carrying out reduction reaction to obtain a product system containing Pd nanoparticles;
the product system containing Pd nano-particles and a carrier Al2O3Mixing and impregnating to obtain Pd/Al2O3A supported catalyst.
5. The method according to claim 4, wherein the Na is2PdCl4Na in solution2PdCl4The mass ratio of the polyvinyl alcohol to the polyvinyl alcohol in the polyvinyl alcohol solution is 2.76: 1.5;
the Na is2PdCl4Na in solution2PdCl4With NaBH4NaBH in solution4In a molar ratio of 1: (4-6).
6. The preparation method according to claim 4, wherein the temperature of the impregnation is 20 to 40 ℃, and the time of the impregnation is 10 to 20 hours.
7. The cerium oxide selectively coated supported palladium catalyst prepared by the preparation method of any one of claims 1 to 6Agent comprising Al2O3And supported on said Al2O3Pd nanoparticles and CeO on a support2(ii) a The CeO2Selectively coating on the surface of the Pd nano-particles.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910076565.0A CN109794241B (en) | 2019-01-26 | 2019-01-26 | Cerium oxide selective coating supported palladium catalyst and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910076565.0A CN109794241B (en) | 2019-01-26 | 2019-01-26 | Cerium oxide selective coating supported palladium catalyst and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109794241A CN109794241A (en) | 2019-05-24 |
| CN109794241B true CN109794241B (en) | 2022-01-28 |
Family
ID=66559045
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910076565.0A Active CN109794241B (en) | 2019-01-26 | 2019-01-26 | Cerium oxide selective coating supported palladium catalyst and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109794241B (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111111676B (en) * | 2020-03-13 | 2021-08-31 | 福州大学 | Coated nickel-based catalyst and preparation method thereof |
| CN111468113A (en) * | 2020-04-08 | 2020-07-31 | 北京工业大学 | Thermal-stable A L D modified CeO with specific crystal face2Preparation of carrier loaded Pd three-way catalyst |
| CN111841631B (en) * | 2020-08-05 | 2021-11-02 | 济南大学 | Polypyrrole-cerium dioxide-gold composite nano material |
| CN112916000B (en) * | 2021-01-15 | 2021-09-28 | 兰州大学 | Photocatalytic material for reducing nitrogen to produce ammonia and preparation method and application thereof |
| CN113058598A (en) * | 2021-03-18 | 2021-07-02 | 北京工业大学 | Improved ALD method for depositing CeO2Method (2) |
| CN113404573B (en) * | 2021-06-08 | 2023-04-07 | 大连理工大学 | Application of supported palladium-cerium-based catalyst for storing nitrogen oxides at low temperature in automobile cold start reaction |
| CN113621264A (en) * | 2021-06-23 | 2021-11-09 | 天津西敦粉漆科技有限公司 | Method for preparing low-temperature curing powder coating in post-mixing mode, related composite nano low-temperature curing catalyst and preparation method thereof |
| CN113578326A (en) * | 2021-08-18 | 2021-11-02 | 哈尔滨工业大学（深圳） | SiO2Ni-loaded double-layer core-shell catalyst and preparation method and application thereof |
| CN114011405B (en) * | 2021-11-22 | 2023-03-28 | 中国科学院大连化学物理研究所 | Preparation method of composite oxide supported catalyst and application of composite oxide supported catalyst in preparation of methyl glycolate from ethylene glycol |
| CN114029053B (en) * | 2021-11-22 | 2023-04-18 | 中国科学院大连化学物理研究所 | Preparation method of supported catalyst and application of supported catalyst in preparation of methyl glycolate from ethylene glycol |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103464152A (en) * | 2013-09-29 | 2013-12-25 | 福州大学 | Catalyst for tail gas purification and preparation method thereof |
| CN103977794A (en) * | 2014-04-29 | 2014-08-13 | 北京化工大学 | Supported noble metal catalyst with three-dimensional structure and preparation method and application thereof |
| CN104084200A (en) * | 2014-06-26 | 2014-10-08 | 北京工业大学 | Three-dimensional orderly macropore InVO4-BiVO4 supported noble metal nanometer photo-catalyst, preparation method and application of photo-catalyst |
| CN108311139A (en) * | 2018-03-19 | 2018-07-24 | 北京工业大学 | A method of improving noble metal nano catalyst thermal stability |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006078777A2 (en) * | 2005-01-19 | 2006-07-27 | William Marsh Rice University | Method to fabricate inhomogeneous particles |
-
2019
- 2019-01-26 CN CN201910076565.0A patent/CN109794241B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103464152A (en) * | 2013-09-29 | 2013-12-25 | 福州大学 | Catalyst for tail gas purification and preparation method thereof |
| CN103977794A (en) * | 2014-04-29 | 2014-08-13 | 北京化工大学 | Supported noble metal catalyst with three-dimensional structure and preparation method and application thereof |
| CN104084200A (en) * | 2014-06-26 | 2014-10-08 | 北京工业大学 | Three-dimensional orderly macropore InVO4-BiVO4 supported noble metal nanometer photo-catalyst, preparation method and application of photo-catalyst |
| CN108311139A (en) * | 2018-03-19 | 2018-07-24 | 北京工业大学 | A method of improving noble metal nano catalyst thermal stability |
Non-Patent Citations (2)
| Title |
|---|
| "L-arignine-Triggered self-assembly of CeO2 Nanosheaths on Palladium Nanoparticles in water";Wang xiao et al.;《Angewandte Chemie-International Edition》;20160307;第55卷(第14期);第4542-4546页 * |
| Wang xiao et al.."L-arignine-Triggered self-assembly of CeO2 Nanosheaths on Palladium Nanoparticles in water".《Angewandte Chemie-International Edition》.2016,第55卷(第14期),第4542-4546页. * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109794241A (en) | 2019-05-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109794241B (en) | Cerium oxide selective coating supported palladium catalyst and preparation method thereof | |
| Xiong et al. | Efficiently multifunctional catalysts of 3D ordered meso-macroporous Ce0. 3Zr0. 7O2-supported PdAu@ CeO2 core-shell nanoparticles for soot oxidation: Synergetic effect of Pd-Au-CeO2 ternary components | |
| Zhao et al. | Influence of thermal treatment on catalytic performance of Pd/(Ce, Zr) Ox–Al2O3 three-way catalysts | |
| CN110327933B (en) | Catalyst for preparing methanol by carbon dioxide hydrogenation, preparation method and application thereof | |
| CN114100594B (en) | Cerium-zirconium-aluminum-based oxide micro-nano composite catalytic material and preparation method thereof | |
| JP5880527B2 (en) | Exhaust gas purification catalyst | |
| JP5531212B2 (en) | Low temperature oxidation catalyst, method for producing the same, and oxidation method using the catalyst | |
| CN104043441A (en) | High-performance cerium-zirconium-silicon composite oxide oxygen-storage material and preparation method | |
| CN102407164A (en) | Cerium zirconium aluminum nanometer composite with mesoporous structure and preparation method and use thereof | |
| CN108452798B (en) | High-temperature-resistant sintering supported noble metal catalyst for catalytic oxidation of carbon monoxide and preparation method thereof | |
| CN111482172B (en) | Composite nano material of CuO/defect titanium dioxide and application thereof | |
| CN111151247A (en) | Supported catalyst and preparation method and application thereof | |
| JP2024501748A (en) | Three-way catalyst supporting noble metal in single atomic state, preparation method and use thereof | |
| EP2729248B1 (en) | Nox purification catalyst and method of producing the same | |
| CN111215061A (en) | Sintering-resistant high-dispersion noble metal catalyst, and preparation and application thereof | |
| CN113145122B (en) | Composite metal oxide catalyst, preparation method thereof and application thereof in catalyzing direct decomposition of nitrogen oxide | |
| EP2823887B1 (en) | Oxidation catalyst and exhaust gas purification method using same | |
| CN110694621A (en) | Three-way catalyst and preparation method and application thereof | |
| Na et al. | Synthesis of neodymium modified CeO2-ZrO2-Al2O3 support materials and their application in Pd-only three-way catalysts | |
| Wang et al. | Evaluation of NO oxidation properties over a Mn-Ce/γ-Al 2 O 3 catalyst | |
| CN111111676A (en) | Coated nickel-based catalyst and preparation method thereof | |
| CN110813301A (en) | High-dispersion supported perovskite catalyst and preparation method and application thereof | |
| CN114192180A (en) | Modified boron nitride loaded nickel-based methane dry reforming catalyst, and preparation method and application thereof | |
| CN106582638A (en) | Preparation method of (Au,Rh)-Cex/Al2O3 applied to NO+CO reaction | |
| CN110694622A (en) | Precious metal-loaded cerium-zirconium composite oxide and preparation method and application thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |