Platinum-cerium-based catalyst as well as preparation method and application thereof

Abstract

The invention provides a platinum-cerium-based catalyst as well as a preparation method and application thereof. The platinum-cerium-based catalyst comprises a cerium-based carrier and platinum-based redox components distributed on the surface of the cerium-based carrier, the platinum-based redox component comprises a platinum nanocluster; the cerium-based carrier comprises a surface vacancy regulator. The surface vacancy regulator is introduced into the platinum-cerium-based catalyst, the alkalinity, oxygen vacancy concentration and cerium vacancy concentration of the surface of the cerium-based carrier are changed, stable existence of platinum nanoclusters under the condition of high-temperature oxidation treatment is achieved, and the stability and catalytic activity of the platinum-cerium-based catalyst are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental protection and air pollution control, in particular to the catalytic oxidation of gaseous pollutants, and in particular to a platinum-cerium based catalyst and a preparation method and application thereof. Background Art

[0002] Cerium-based oxides have strong oxygen storage and release capabilities. When combined with redox components (such as Pt, Pd, Ir, etc.), they can catalyze most reactions including CO oxidation, water gas shift, alkane dehydrogenation, etc. In particular, Pt / CeO 2 It can effectively eliminate pollutants such as CO and NO in automobile exhaust and is an important component of the three-way catalyst. In order to cope with complex working conditions and strict emission standards, it is necessary to improve the stability test of the catalyst under low and high temperature conditions to meet the exhaust treatment requirements during the normal operation of the automobile.

[0003] Pt / CeO 2 It is a material system with strong metal-support interaction. When in oxygen-rich and high-temperature conditions, Pt clusters with high CO oxidation activity will form on CeO 2 Completely dispersed Pt single atoms gradually form on the surface. At this time, due to the strong binding of the overly stable Pt single atoms to the carrier, the ability to form bonds with the gas-phase species CO and the ability to activate CO are significantly reduced, resulting in a significant decrease in the catalytic activity of the catalyst for CO.

[0004] CN115770570A discloses a cerium oxide supported atomic level dispersed Pt catalyst and a redispersion preparation method thereof, comprising: first preparing CeO 2 The Pt nanoparticle catalyst was loaded and then calcined at high temperature in an oxidizing atmosphere. 2 The redispersion occurs on the (100) crystal plane, and the dispersion of Pt is regulated by adjusting the Pt loading to achieve atomic-level dispersion, that is, the CeO 2 Loading atomic-level dispersed Pt catalyst. By regulating the amount of Pt loading, not only can the particle size be controlled from single atoms, multiple atoms to clusters, but also the distance between single atoms can be controlled within the range of CeO 2 Control of surface distribution.

[0005] CN101670286A discloses a method of preparing a type of supported transition metal or alloy nanocluster catalyst by loading a transition metal or alloy nanocluster synthesized by an "alkali-polyol method" and stabilized by a solvent and simple ions on a carbon or oxide carrier. The content of the transition metal or alloy nanocluster in the catalyst is 0.1wt%-50wt%, and the particle size is 0.7nm-5nm. The transition metal or alloy nanocluster in the catalyst is distributed on the outer surface or in the mesopores and macropores of the carrier material, and the surface atoms of the metal or alloy nanocluster have a high utilization rate.

[0006] CN114832817A discloses a sheet-like atomic-grade Pt / CeO with ultra-high Pt loading. 2 The catalyst has a high loading of Pt, which is still atomically dispersed at 10%, and has a significantly better catalytic water vapor shift performance than commercial CeO 2 Pt / CeO prepared by support 2 Catalyst and microspherical atomic-scale Pt / CeO 2 Catalyst. However, this technology requires ultra-high Pt loading to overcome the Pt / CeO 2 The application is limited and the cost is significantly increased.

[0007] Therefore, there is an urgent need to design a highly stable cerium-based oxide-loaded platinum catalyst to ensure that the platinum nanoclusters can exist stably at high temperatures when the car is operating normally, so that the pollutant gases in the exhaust gas can be effectively treated for a long time. Summary of the invention

[0008] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a platinum-cerium-based catalyst and a preparation method and application thereof. The present invention introduces a surface vacancy regulator into the platinum-cerium-based catalyst to change the alkalinity, oxygen vacancy concentration and cerium vacancy concentration of the cerium-based carrier surface, thereby weakening the strong interaction between the platinum-based redox component and the cerium-based carrier, achieving the stable existence of platinum nanoclusters under high-temperature oxidation treatment conditions, significantly improving the stability and catalytic activity of the platinum-cerium-based catalyst, and having relatively excellent catalytic performance even in an oxygen-rich high-temperature environment, as well as strong resistance to environmental interference.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a platinum-cerium-based catalyst, the platinum-cerium-based catalyst comprising a cerium-based carrier and a platinum-based redox component distributed on the surface of the cerium-based carrier;

[0011] The platinum-based redox component includes platinum nanoclusters;

[0012] The cerium-based support includes cerium dioxide and a surface vacancy regulator.

[0013] The present invention introduces a surface vacancy regulator into the platinum-cerium-based catalyst to change the alkalinity, oxygen vacancy concentration and cerium vacancy concentration of the cerium-based carrier surface, thereby weakening the strong interaction between the platinum-based redox component and the cerium-based carrier, achieving the stable existence of platinum nanoclusters under high-temperature oxidation treatment conditions, and significantly improving the stability and catalytic activity of the platinum-cerium-based catalyst.

[0014] In the present invention, the surface vacancy regulator is a metal element with a large ion radius or high electronegativity, which can adjust the pH of the carrier surface, so that the Lewis base content and strength of the carrier surface are reduced, which is comprehensively manifested as a reduction in the low-coordinated O content on the carrier surface and a reduction in the cerium vacancy content, so that the proportion of platinum occupying cerium vacancies to form Pt-O-Ce single atomic bonds is significantly reduced, achieving the purpose of controlling the number of single atomic dispersion sites and increasing the proportion of platinum nanoclusters. At the same time, under the action of the surface vacancy regulator, a high concentration of oxygen vacancies can also be formed inside and on the surface of the cerium-based carrier, thereby maintaining electrical neutrality and reducing the internal stress of the system.

[0015] In the present invention, the platinum-based redox component exists in the form of zero valence or partial oxidation state.

[0016] Preferably, the surface vacancy modifier comprises an ionic radius and / or elements with electronegativity ≥ 1.7.

[0017] Preferably, the surface vacancy regulator includes any one of neodymium (Nd), bismuth (Bi), tungsten (W) or molybdenum (Mo) or a combination of at least two thereof.

[0018] In the present invention, the molar percentage of the surface vacancy regulator affects the alkalinity, oxygen vacancy concentration and cerium vacancy concentration of the surface of the cerium-based carrier, and further affects the strength of the interaction between the platinum-based redox component and the cerium-based carrier, thereby achieving the stable existence of platinum nanoclusters under high-temperature oxidation treatment conditions. If the molar percentage of the surface vacancy regulator is too high, excessively high concentrations of oxygen vacancies will be introduced, inhibiting the oxygen storage and release capacity of the cerium-based carrier and even causing phase separation. If the molar percentage of the surface vacancy regulator is too low, the redispersion of the platinum nanoclusters cannot be effectively inhibited.

[0019] Preferably, in the cerium-based carrier, the molar percentage of the surface vacancy regulator is 8%-30%, for example, it can be 8%, 10%, 12%, 14%, 16%, 18%, 20%, 21%, 23%, 25%, 27%, 29% or 30%, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 10%-20%.

[0020] In the present invention, the average size of the platinum nanoclusters affects the catalytic activity of the reaction. If the average size of the platinum-cerium-based catalyst is too small, it is very easy to form single atomic platinum, which limits the adsorption and activation of CO. If the average size is too large, the atomic utilization efficiency is low, resulting in the inability to fully utilize the platinum inside the particles.

[0021] Preferably, the average size of the platinum nanoclusters is 1nm-5nm, for example, 1nm, 1.5nm, 2nm, 2.5nm, 3nm, 4nm or 5nm, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 1nm-3nm.

[0022] In the present invention, in the platinum-cerium based catalyst, the mass percentage of the platinum based reducing component also affects the reaction activity. If the mass percentage of the platinum based reducing component is too large, although the platinum nanoclusters do not have the difficulty of redispersion, the catalytic activity of the system will have an upper limit, and the excess platinum atoms cannot be effectively utilized. If the mass percentage of the platinum based reducing component is too small, platinum single atoms with lower activity will be formed.

[0023] Preferably, in the platinum-cerium based catalyst, the mass percentage of the platinum based reducing component is 0.1%-5%, for example, it can be 0.1%, 0.3%, 0.5%, 0.7%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 0.5%-1%.

[0024] Preferably, the platinum-based redox component further comprises a second metal.

[0025] In the present invention, a second metal is introduced into the platinum-based redox component to form a synergistic effect, which is beneficial to promoting the reaction.

[0026] Preferably, the second metal includes any one or a combination of at least two of Pd, Ru or Ir. Typical but non-limiting combinations include Pd and Ru, Pd and Ir or Ru and Ir.

[0027] Preferably, the mass percentage of the second metal is ≤30%, for example, it can be 0, 5%, 10%, 15%, 20%, 25% or 30%, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] Preferably, the cerium-based support further comprises a metal oxide.

[0029] In the present invention, the introduction of metal oxides into the cerium-based carrier is beneficial to improving the high-temperature stability of the carrier and preventing the specific surface area of ​​cerium oxide from being seriously reduced due to excessively high operating temperatures.

[0030] Preferably, the mass percentage of metal oxide in the cerium-based carrier is ≤20%, for example, it can be 0%, 5%, 10%, 15% or 20%, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] Preferably, the metal oxide comprises any one of aluminum oxide, manganese dioxide, titanium dioxide, cobalt oxide, nickel oxide or copper oxide, or a combination of at least two thereof. Typical but non-limiting combinations include manganese dioxide and titanium dioxide, cobalt oxide and nickel oxide, titanium dioxide and cobalt oxide, or copper oxide and manganese dioxide.

[0032] In a second aspect, the present invention provides a method for preparing the platinum-cerium based catalyst as described in the first aspect, the preparation method comprising:

[0033] The cerium-based carrier and the platinum-based nanoparticle solution are mixed, dried to obtain a platinum-cerium-based catalyst precursor, and the platinum-cerium-based catalyst precursor is calcined to obtain the platinum-cerium-based catalyst.

[0034] In the present invention, after the cerium-based carrier is mixed with the platinum-based nanoparticle solution, the drying method of the platinum-cerium-based catalyst precursor is not particularly limited, and the purpose is to achieve complete volatilization of the solvent.

[0035] Preferably, the temperature for drying the platinum-cerium based catalyst precursor is 50°C-80°C, for example, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C, including but not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0036] Preferably, the preparation method of the cerium-based carrier comprises:

[0037] A cerium source, a surface vacancy regulator precursor and a solvent are mixed to obtain a mixed solution, a cerium-based carrier precursor is reacted to obtain the cerium-based carrier, and the cerium-based carrier precursor is calcined to obtain the cerium-based carrier.

[0038] Preferably, in the mixed solution, the concentrations of the cerium source and the surface vacancy regulator precursor are independently 0.1 mmol / mL-0.5 mmol / mL, for example, 0.1 mmol / mL, 0.2 mmol / mL, 0.3 mmol / mL, 0.4 mmol / mL or 0.5 mmol / mL, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the molar ratio of the cerium source to the surface vacancy modifier precursor in the mixed solution is (70-92):(8-30), for example, it can be 70:30, 72:28, 74:26, 76:24, 78:22, 80:20, 82:18, 84:16, 86:14, 88:12, 90:10 or 92:8, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] Preferably, the cerium source includes any one of cerium nitrate and cerium chloride or a combination of both.

[0041] Preferably, the surface vacancy modifier precursor includes any one of neodymium salt, bismuth salt, tungstate or molybdate, or a combination of at least two thereof.

[0042] Preferably, the surface vacancy modifier precursor includes any one of neodymium nitrate, bismuth nitrate, ammonium metatungstate and ammonium molybdate, or a combination of at least two of them.

[0043] Preferably, the solvent comprises water and / or ethanol.

[0044] Preferably, the method for obtaining the cerium-based carrier precursor by the reaction comprises any one of a chemical coprecipitation method, a hydrothermal method or a sol-gel method.

[0045] Preferably, the method for preparing the cerium-based carrier further comprises aging and drying the prepared cerium-based carrier precursor.

[0046] Preferably, the aging temperature is 20°C-40°C, for example, it can be 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 34°C, 36°C, 38°C or 40°C, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] Preferably, the aging time is 4h-12h, for example, it can be 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h or 12h, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0048] Preferably, the drying temperature is 60°C-100°C, for example, it can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0049] Preferably, the temperature for calcining the cerium-based carrier precursor is 500°C-600°C, for example, it can be 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C or 600°C, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0050] Preferably, the calcination time of the cerium-based carrier precursor is 3h-6h, for example, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h or 6h, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0051] Preferably, the heating rate for calcining the cerium-based carrier precursor is 2°C / min-10°C / min, for example, it can be 2°C / min, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min or 10°C / min, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0052] In the present invention, the concentration of platinum-based nanoparticles in the platinum-based nanoparticle solution affects the initial dispersion of platinum nanoclusters on the carrier surface. If the concentration is too high, it is not conducive to the uniform dispersion of platinum on the carrier surface, and agglomeration may occur, thereby leading to a misjudgment of the dispersibility of the platinum nanoclusters.

[0053] Preferably, the concentration of platinum-based nanoparticles in the platinum-based nanoparticle solution is 1 mg / mL-3 mg / mL, for example, 1 mg / mL, 1.2 mg / mL, 1.4 mg / mL, 1.6 mg / mL, 1.8 mg / mL, 2 mg / mL, 2.2 mg / mL, 2.4 mg / mL, 2.6 mg / mL, 2.8 mg / mL or 3 mg / mL, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0054] Preferably, the platinum-based nanoparticles are prepared by reducing a platinum-based precursor.

[0055] Preferably, the platinum-based precursor comprises a platinum salt and a second metal salt.

[0056] Preferably, the platinum salt comprises any one of platinum nitrate, platinum acetylacetonate, platinum chloride or platinum acetate, or a combination of at least two thereof. Typical but non-limiting combinations include platinum nitrate and platinum acetylacetonate, platinum chloride and platinum acetate, platinum acetylacetonate and platinum chloride, or platinum acetate and platinum nitrate.

[0057] Preferably, the second metal salt includes any one of a Pd salt, a Ru salt or an Ir salt, or a combination of at least two of them. Typical but non-limiting combinations include a Pd salt and a Ru salt, a Pd salt and an Ir salt, or a Ru salt and an Ir salt.

[0058] Preferably, the Pd salt comprises palladium nitrate and / or palladium chloride.

[0059] Preferably, the Ru salt includes ruthenium chloride and / or ruthenium acetate.

[0060] Preferably, the Ir salt includes any one of iridium trichloride, ammonium iridate or iridium tetrachloride, or a combination of at least two thereof. Typical but non-limiting combinations include iridium trichloride and ammonium iridate, iridium tetrachloride and iridium trichloride, or ammonium iridate and iridium tetrachloride.

[0061] Preferably, the method of reducing the platinum-based precursor includes any one of an ethylene glycol reduction method, an ethanol reduction method or a sodium borohydride reduction method.

[0062] Preferably, the temperature of reducing the platinum-based precursor is 120°C-160°C, for example, 120°C, 130°C, 140°C, 150°C or 160°C, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0063] Preferably, the time for reducing the platinum-based precursor is 3h-8h, for example, 3h, 4h, 5h, 6h, 7h or 8h, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0064] In the present invention, after the reaction of reducing the platinum-based precursor is completed, the platinum-based nanoparticles are washed by centrifugation with acetone, and then dispersed with ethanol and the concentration is measured by ICP to prepare a platinum-based nanoparticle solution.

[0065] Preferably, the method of mixing the cerium-based carrier and the platinum-based nanoparticle solution comprises stirring.

[0066] Preferably, the stirring rate is 300 r / min-800 r / min, for example, it can be 300 r / min, 400 r / min, 500 r / min, 600 r / min, 700 r / min or 800 r / min, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0067] Preferably, the stirring time is 2h-4h, for example, 2h, 2.5h, 3h, 3.5h or 4h, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0068] Preferably, the temperature for drying the platinum-cerium based catalyst precursor is 50°C-80°C, for example, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C, including but not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0069] In the present invention, the temperature of calcining the platinum-cerium-based catalyst precursor affects the dispersion state of platinum. If the temperature is too high, the stability of the surface vacancy regulator deteriorates, resulting in an unsatisfactory effect of inhibiting the redispersion of platinum nanoclusters. For example, the Bi element will have a certain volatility after exceeding 700°C.

[0070] Preferably, the temperature for calcining the platinum-cerium based catalyst precursor is 400°C-600°C, for example, 400°C, 450°C, 500°C, 550°C or 600°C, including but not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0071] Preferably, the calcination time of the platinum-cerium based catalyst precursor is 4h-12h, for example, it can be 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h or 12h, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0072] Preferably, the heating rate for calcining the platinum-cerium based catalyst precursor is 2°C / min-5°C / min, for example, 2°C / min, 2.5°C / min, 3°C / min, 3.5°C / min, 4°C / min, 4.5°C / min or 5°C / min, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0073] In a third aspect, the present invention provides a use of the platinum-cerium based catalyst as described in the first aspect, wherein the platinum-cerium based catalyst is used for catalytic oxidation removal of gaseous pollutants.

[0074] Compared with the prior art, the present invention has the following beneficial effects:

[0075] (1) The present invention introduces a surface vacancy regulator into the platinum-cerium-based catalyst to change the alkalinity, oxygen vacancy concentration and cerium vacancy concentration of the cerium-based carrier surface, thereby weakening the strong interaction between the platinum-based redox component and the cerium-based carrier, thereby achieving the stable existence of platinum nanoclusters under high-temperature oxidation treatment conditions, significantly improving the stability and catalytic activity of the platinum-cerium-based catalyst, and having relatively excellent catalytic performance even in an oxygen-rich high-temperature environment, as well as strong resistance to environmental interference.

[0076] (2) The preparation method of the platinum-cerium-based catalyst provided by the present invention is simple, low-cost, and has a wide range of applications. It not only broadens the scope of use of the platinum-cerium-based catalyst under high-temperature oxidation conditions, but also provides an efficient, economical, and widely applicable catalyst preparation method in practical applications.

[0077] (3) The CO complete conversion temperature of the platinum-cerium-based catalyst provided by the present invention under the condition of 30000 mL / (h·g) is lower than 180°C, and can even be lower than 140°C; and after the catalyst is treated at 500°C and air conditions for 4 hours, the reaction temperature rise corresponding to the CO conversion rate of 50% is less than 15°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 This is the activity curve of the platinum-cerium based catalyst prepared in the present invention under the condition of 30000 mL / (h·g).

[0079] Figure 2 This is the activity curve of the platinum-cerium based catalyst prepared in the present invention under the condition of 150000 mL / (h·g).

[0080] Figure 3 This is the in-situ infrared curve of carbon monoxide of the platinum-cerium based catalyst prepared in Example 1 of the present invention.

[0081] Figure 4 This is the in-situ infrared curve of carbon monoxide of the platinum-cerium based catalyst prepared in Example 2 of the present invention.

[0082] Figure 5 This is the in-situ infrared curve of carbon monoxide of the platinum-cerium based catalyst prepared in Comparative Example 1 of the present invention.

[0083] Figure 6 This is the in-situ infrared curve of carbon monoxide of the platinum-cerium based catalyst prepared in Comparative Example 2 of the present invention.

[0084] Figure 7 The XPS Pt spectra of the platinum-cerium based catalysts prepared in Example 1 of the present invention and Comparative Example 1 are shown.

[0085] Figure 8 The XPS O spectra of the platinum-cerium based catalysts prepared in Example 1 of the present invention and Comparative Example 1 are shown.

[0086] Fig. 9 The XPS Pt spectra of the platinum-cerium based catalysts prepared in Example 2 of the present invention and Comparative Example 2 are shown.

[0087] Fig.10 The XPS O spectra of the platinum-cerium based catalysts prepared in Example 2 of the present invention and Comparative Example 2 are shown.

[0088] Fig.11CO of the cerium-based catalyst prepared in Example 1 and Comparative Example 1 of the present invention 2 Programmed desorption curve.

[0089] Fig.12 This is a spherical aberration electron microscope image of the platinum-cerium based catalyst prepared in Example 2 of the present invention.

[0090] Fig.13 This is a spherical aberration electron microscope image of the platinum-cerium based catalyst prepared in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0091] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only used to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0092] Example 1

[0093] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 1 wt %, and the molar percentage of the bismuth surface vacancy regulator in the cerium-based carrier is 10%.

[0094] The preparation method of the platinum-cerium based catalyst comprises:

[0095] (1) Preparation of cerium-based carrier by coprecipitation method: 2.3158 g of cerium nitrate hexahydrate and 0.2856 g of bismuth nitrate pentahydrate were weighed and completely dissolved in 30 mL of 2 mol / L HNO 3 In the stirring state, ammonia water was added dropwise to adjust the pH of the solution to 9.5. Stirring was continued for 1 hour and aged at 30°C for 8 hours. Then, the sample was centrifuged and washed twice with water and ethanol (4000rpm, 5min), and the sample was dried at 60°C to obtain a cerium-based carrier precursor. The cerium-based carrier precursor was calcined in a muffle furnace at a heating rate of 5°C / min, a calcination temperature of 500°C, and a calcination time of 4h to obtain a cerium-based carrier.

[0096] (2) Preparation of platinum nanoparticle solution: 465 mg Pt(NO 3 ) 2 (16.76 wt%) was dissolved in 9 mL of ethylene glycol. 315 mg of PVP (k30) was weighed and dissolved in 24 mL of ethylene glycol. The two solutions were mixed and placed in a 100 mL three-necked flask. N 2 The reaction gas was purged, and then heated to 120°C for 5 hours, and then washed by centrifugation with 9 volumes of acetone, and finally dispersed with ethanol to obtain a platinum nanoparticle solution. After preparation, the concentration of the nanoparticle solution was determined by ICP and controlled at 2.5 mg / mL.

[0097] (3) Preparation of platinum-cerium-based catalyst: 4 mL of the platinum nanoparticle solution obtained in step (2) was added to 990 mg of the carrier obtained in step (1), and stirred at room temperature for 3 h on an electromagnetic stirrer with a magnetic speed of 300 r / min, then stirred and dried at 60°C, and finally calcined at 400°C in a muffle furnace for 4 h with a calcination heating rate of 5°C / min to finally obtain a platinum-cerium-based catalyst.

[0098] Example 2

[0099] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 1 wt %, and the molar percentage of the bismuth surface vacancy regulator in the cerium-based carrier is 10%.

[0100] The preparation method of the platinum-cerium based catalyst comprises:

[0101] (1) Preparation of cerium-based carrier by coprecipitation method: 2.3158 g of cerium nitrate hexahydrate and 0.2856 g of bismuth nitrate pentahydrate were weighed and completely dissolved in 30 mL of 2 mol / L HNO 3 In the stirring state, ammonia water was added dropwise to adjust the pH of the solution to 9.5. Stirring was continued for 1 hour and aged at 30°C for 8 hours. Then, the sample was centrifuged and washed twice with water and ethanol (4000rpm, 5min), and the sample was dried at 60°C to obtain a cerium-based carrier precursor. The cerium-based carrier precursor was calcined in a muffle furnace at a heating rate of 5°C / min, a calcination temperature of 500°C, and a calcination time of 4h to obtain a cerium-based carrier.

[0102] (2) Preparation of platinum nanoparticle solution: 465 mg Pt(NO 3 ) 2 (16.76 wt%) was dissolved in 9 mL of ethylene glycol. 315 mg of PVP (k30) was weighed and dissolved in 24 mL of ethylene glycol. The two solutions were mixed and placed in a 100 mL three-necked flask. N 2 The reaction gas was purged, and then heated to 120°C for 5 hours, and then washed by centrifugation with 9 volumes of acetone, and finally dispersed with ethanol to obtain a platinum nanoparticle solution. After preparation, the concentration of the nanoparticle solution was determined by ICP and controlled at 2.5 mg / mL.

[0103] (3) Preparation of platinum-cerium-based catalyst: 4 mL of the platinum nanoparticle solution obtained in step (2) was added to 990 mg of the carrier obtained in step (1), and stirred at room temperature for 3 h on an electromagnetic stirrer with a magnetic speed of 300 r / min, then stirred and dried at 60°C, and finally calcined at 500°C in a muffle furnace for 4 h with a calcination heating rate of 5°C / min to finally obtain a platinum-cerium-based catalyst.

[0104] Example 3

[0105] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 1 wt %, and the molar percentage of the bismuth surface vacancy regulator in the cerium-based carrier is 15%.

[0106] The preparation method of the platinum-cerium based catalyst is the same as that of Example 1 except that the mass of the Ce precursor in step (1) of Example 1 is changed to 2.1871 g and the mass of the Bi precursor is changed to 0.4312 g.

[0107] Example 4

[0108] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 1 wt %, and the molar percentage of the bismuth surface vacancy regulator in the cerium-based carrier is 15%.

[0109] The preparation method of the platinum-cerium based catalyst is the same as that of Example 2 except that the mass of the Ce precursor in step (1) of Example 1 is changed to 2.1871 g and the mass of the Bi precursor is changed to 0.4312 g.

[0110] Example 5

[0111] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 1 wt %, and the molar percentage of the bismuth surface vacancy regulator in the cerium-based carrier is 20%.

[0112] The preparation method of the platinum-cerium based catalyst is the same as that of Example 1 except that the mass of the Ce precursor in step (1) of Example 1 is changed to 2.0585 g and the mass of the Bi precursor is changed to 0.5749 g.

[0113] Example 6

[0114] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 1 wt %, and the molar percentage of the bismuth surface vacancy regulator in the cerium-based carrier is 20%.

[0115] The preparation method of the platinum-cerium based catalyst is the same as that of Example 2 except that the mass of the Ce precursor in step (1) of Example 1 is changed to 2.0585 g and the mass of the Bi precursor is changed to 0.5749 g.

[0116] Example 7

[0117] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 4.5wt%, and the molar percentage of the neodymium surface vacancy regulator in the cerium-based carrier is 10%.

[0118] The preparation method of the platinum-cerium based catalyst comprises:

[0119] (1) Preparation of cerium-based carrier by coprecipitation method: 1.8012 g of cerium nitrate hexahydrate and 0.2598 g of neodymium nitrate hexahydrate were weighed and completely dissolved in 30 mL of H 2 O, and add ammonia water dropwise under stirring to adjust the pH of the solution to 9. Continue stirring for 1 hour and age at 20°C for 12 hours. Then centrifuge and wash twice with water and ethanol (4000rpm, 5min), respectively, and dry the sample at 100°C to obtain a cerium-based carrier precursor. The cerium-based carrier precursor is calcined in a muffle furnace at a heating rate of 2°C / min, a calcination temperature of 600°C, and a calcination time of 3h to obtain a cerium-based carrier.

[0120] (2) Preparation of platinum nanoparticle solution: weigh 465 mg Pt(NO 3 ) 2 (16.76 wt%) was dissolved in 9 mL of ethylene glycol. 315 mg of PVP (k30) was weighed and dissolved in 24 mL of ethylene glycol. The two solutions were mixed and placed in a 100 mL three-necked flask. N 2 The reaction gas was purged, and then heated to 120°C for 5 hours, and then washed by centrifugation with 9 volumes of acetone, and finally dispersed with ethanol to obtain a platinum nanoparticle solution. After preparation, the concentration of the nanoparticle solution was determined by ICP and controlled at 3 mg / mL.

[0121] (3) Preparation of platinum-cerium-based catalyst: 15 mL of the platinum nanoparticle solution obtained in step (2) was added to 955 mg of the carrier obtained in step (1), and stirred at room temperature for 2 h on an electromagnetic stirrer with a magnetic speed of 800 r / min, then stirred and dried at 80°C, and finally calcined at 500°C in a muffle furnace for 12 h with a calcination heating rate of 2°C / min to finally obtain a platinum-cerium-based catalyst.

[0122] Example 8

[0123] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 0.5wt%, and the molar percentage of the tungsten surface vacancy regulator in the cerium-based carrier is 20%.

[0124] The preparation method of the platinum-cerium based catalyst comprises:

[0125] (1) Preparation of cerium-based carrier by coprecipitation method: 2.3673 g of cerium nitrate hexahydrate and 0.29 g of ammonium metatungstate were weighed and completely dissolved in 30 mL of H 2O, and ammonia water was added dropwise under stirring to adjust the pH of the solution to 11. Stirring was continued for 1 hour, and aging was carried out at 40°C for 4 hours. Then, the sample was centrifuged and washed twice with water and ethanol (4000rpm, 5min), and the sample was dried at 80°C to obtain a cerium-based carrier precursor. The cerium-based carrier precursor was calcined in a muffle furnace, the heating rate of calcination was 10°C / min, the calcination temperature was 550°C, and the calcination time was 6h to obtain a cerium-based carrier.

[0126] (2) Preparation of platinum nanoparticle solution: 465 mg Pt(NO 3 ) 2 (16.76 wt%) was dissolved in 9 mL of ethylene glycol. 315 mg of PVP (k30) was weighed and dissolved in 24 mL of ethylene glycol. The two solutions were mixed and placed in a 100 mL three-necked flask. N 2 The reaction gas was purged, and then heated to 120°C for 5 hours, and then washed by centrifugation with 9 volumes of acetone, and finally dispersed with ethanol to obtain a platinum nanoparticle solution. After preparation, the concentration of the nanoparticle solution was determined by ICP and controlled at 1 mg / mL.

[0127] (3) Preparation of platinum-cerium-based catalyst: 5 mL of the platinum nanoparticle solution obtained in step (2) was added to 995 mg of the carrier obtained in step (1), and stirred at room temperature for 4 h on an electromagnetic stirrer with a magnetic speed of 500 r / min, then stirred and dried at 50°C, and finally calcined at 600°C in a muffle furnace for 8 h with a calcination heating rate of 3°C / min to finally obtain a platinum-cerium-based catalyst.

[0128] Example 9

[0129] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 2 wt %, and the molar percentage of the molybdenum surface vacancy regulator in the cerium-based carrier is 10%.

[0130] The preparation method of the platinum-cerium based catalyst comprises:

[0131] (1) Preparation of cerium-based carrier by coprecipitation method: 0.1039 g ammonium molybdate and 2 g citric acid were weighed and completely dissolved in 30 mL H 2 After O, 2.3158g of cerium nitrate hexahydrate was added, and ammonia water was added dropwise under stirring to adjust the pH of the solution to 10. Stirring was continued for 1h and aged at 40°C for 4h. Then, the sample was centrifuged and washed twice with water and ethanol (4000rpm, 5min), and the sample was dried at 80°C to obtain a cerium-based carrier precursor. The cerium-based carrier precursor was calcined in a muffle furnace at a heating rate of 10°C / min, a calcination temperature of 550°C, and a calcination time of 6h to obtain a cerium-based carrier.

[0132] (2) Preparation of platinum nanoparticle solution: 465 mg Pt(NO 3 ) 2 (16.76 wt%) and 315 mg PVP

[0133] (k30) was completely dissolved in 9 mL and 24 mL of ethylene glycol, and then the two solutions were mixed and placed in a 100 mL three-necked flask. 2 The reaction gas was purged, and then heated to 120°C for 5 hours, and then washed by centrifugation with 9 volumes of acetone, and finally dispersed with ethanol to obtain a platinum nanoparticle solution. After preparation, the concentration of the nanoparticle solution was determined by ICP and controlled at 1 mg / mL.

[0134] (3) Preparation of platinum-cerium-based catalyst: 20 mL of the platinum nanoparticle solution obtained in step (2) was added to 980 mg of the carrier obtained in step (1), and stirred at room temperature for 4 h on an electromagnetic stirrer with a magnetic speed of 500 r / min, then stirred and dried at 50°C, and finally calcined at 600°C in a muffle furnace for 8 h with a calcination heating rate of 3°C / min to finally obtain a platinum-cerium-based catalyst.

[0135] Example 10

[0136] This embodiment provides a platinum-cerium-based catalyst, in which Pt 9 Ru 1 The loading amount is 1 wt %, and the molar percentage of the bismuth surface vacancy regulator in the cerium-based carrier is 10%.

[0137] The method for preparing the platinum-cerium based catalyst is the same as that of Example 2 except that the method for preparing the platinum nanoparticle solution in step (2) is different from that in Example 1.

[0138] The method for preparing the platinum nanoparticle solution in step (2) of this embodiment includes:

[0139] Preparation of platinum nanoparticle solution: weigh 418 mg Pt(NO 3 ) 2 (16.76 wt%) and 95 mg RuCl 3 Dissolve in 9 mL of ethylene glycol. Weigh 315 mg of PVP (k30) and dissolve in 24 mL of ethylene glycol. Then mix the two solutions and place them in a 100 mL three-necked flask. First, pass N 2 The reaction gas was purged, and then heated to 120 °C for 5 h, and then centrifuged and washed with 9 times the volume of acetone, and finally dispersed with ethanol to obtain Pt 9 Ru 1 Nanoparticle solution: After preparation, the concentration of the nanoparticle solution was determined by ICP and controlled at 2.5 mg / mL.

[0140] Embodiment 11

[0141] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 1 wt %, and the molar percentage of the bismuth surface vacancy regulator in the cerium-based carrier is 10%.

[0142] The preparation method of the platinum-cerium-based catalyst is as follows: except that in step (1), 2.3158 g of cerium nitrate hexahydrate, 0.5 g of aluminum oxide and 0.2856 g of bismuth nitrate pentahydrate are weighed and completely dissolved in 30 mL of HNO with a molar concentration of 2 mol / L. 3 The rest is the same as in Example 1.

[0143] Example 12

[0144] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 1 wt %, and the molar percentage of the bismuth surface vacancy regulator in the cerium-based carrier is 5%.

[0145] The preparation method of the platinum-cerium-based catalyst is as follows: in step (1), 2.4444 g of cerium nitrate hexahydrate and 0.1437 g of bismuth nitrate pentahydrate are weighed and completely dissolved in 30 mL of HNO with a molar concentration of 2 mol / L. 3 The rest is the same as in Example 1.

[0146] Example 13

[0147] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 1 wt %, and the molar percentage of the bismuth surface vacancy regulator in the cerium-based carrier is 5%.

[0148] The preparation method of the platinum-cerium-based catalyst is as follows: in step (1), 2.4444 g of cerium nitrate hexahydrate and 0.1437 g of bismuth nitrate pentahydrate are weighed and completely dissolved in 30 mL of HNO with a molar concentration of 2 mol / L. 3 The rest is the same as in Example 2.

[0149] Embodiment 14

[0150] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 1 wt %, and the molar percentage of the bismuth surface vacancy regulator in the cerium-based carrier is 35%.

[0151] The preparation method of the platinum-cerium-based catalyst is as follows: except that in step (1), 2.5087 g of cerium nitrate hexahydrate and 1.4994 g of bismuth nitrate pentahydrate are weighed and completely dissolved in 30 mL of HNO with a molar concentration of 2 mol / L. 3The rest is the same as in Example 1.

[0152] Embodiment 15

[0153] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 0.05 wt %, and the molar percentage of the bismuth surface vacancy regulator in the cerium-based carrier is 10%.

[0154] The preparation method of the platinum-cerium-based catalyst is the same as that of Example 1, except that in step (3), 0.2 mL of the platinum solution of step (2) is added to 999.5 mg of the carrier obtained in step (1).

[0155] Example 16

[0156] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 6 wt %, and the molar percentage of the bismuth surface vacancy regulator in the cerium-based carrier is 10%.

[0157] The preparation method of the platinum-cerium-based catalyst is the same as that of Example 1, except that in step (3), 24 mL of the platinum solution of step (2) is added to 940 mg of the carrier obtained in step (1).

[0158] Embodiment 17

[0159] This embodiment provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 1 wt %, and the molar percentage of the neodymium surface vacancy regulator in the cerium-based carrier is 10%.

[0160] The preparation method of the platinum-cerium based catalyst is the same as that of Example 1 except that the calcination temperature in step (3) is 700°C.

[0161] Comparative Example 1

[0162] This comparative example provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 1 wt %, and the cerium-based carrier does not contain a surface vacancy regulator.

[0163] The preparation method of the platinum-cerium based catalyst is the same as that of Example 1 except that bismuth nitrate pentahydrate is not added in step (1).

[0164] Comparative Example 2

[0165] This comparative example provides a platinum-cerium-based catalyst, in which the loading amount of the platinum-based redox component is 1 wt %, and the cerium-based carrier does not contain a surface vacancy regulator.

[0166] The preparation method of the platinum-cerium based catalyst is the same as that of Example 2 except that bismuth nitrate pentahydrate is not added in step (1).

[0167] Comparative Example 3

[0168] This comparative example provides a cerium-based catalyst, the cerium-based catalyst is not loaded with platinum, and the molar percentage of the bismuth surface vacancy regulator in the cerium-based carrier is 10%.

[0169] The method for preparing the cerium-based catalyst is the same as that of Example 1, except that step (2) is not performed and step (3) is not performed without adding the platinum nanoparticle solution.

[0170] Performance Test:

[0171] The catalysts provided in all the above examples and comparative examples were tested for conversion rate of catalytic carbon monoxide combustion at different temperatures.

[0172] Test method: Weigh a certain amount of catalyst and mix it with 180 mg of quartz sand, then place it in a quartz tube for reaction activity determination.

[0173] Measurement conditions: for a space velocity SV of 150000 mL / (h·g), a total flow rate of 50 mL / min, and a catalyst mass of 20 mg; for a space velocity SV of 30000 mL / (h·g), a total flow rate of 25 mL / min, and a catalyst mass of 50 mg.

[0174] The reaction raw gas includes 0.5 vol% CO and 10 vol% O 2 , nitrogen is the balance gas. The concentration of CO in the tail gas is monitored by a GC-2060 gas chromatograph (FID detector). The conversion efficiency of the catalyst to CO is calculated by the following formula: R = (C 0 -C 1 ) / C 0 ×100%, R is the conversion rate of CO, C 0 is the concentration of reactive gas CO at the inlet, C 1 is the concentration of outlet reaction gas CO, and the temperature points corresponding to CO conversion rates of 50% and 100% (i.e., T 50 、T 100 ) to evaluate the activity of the catalyst.

[0175] The test results are shown in Table 1 (30000mL / (h·g)) and Table 2 (150000mL / (h·g)) and Figure 1 and Figure 2 As shown in Table 1, ΔT 50 The T of the samples prepared at 500℃ and 400℃ 50 Difference, ΔT of Table 2 50The T of the sample prepared at 500°C and the T of Comparative Example 1 50 Difference.

[0176] The platinum-cerium based catalysts prepared in Example 1-Example 2 and Comparative Example 1-Comparative Example 2 were subjected to an infrared test of carbon monoxide in-situ adsorption and desorption.

[0177] The test method is as follows: first, the sample to be tested is heated at 300°C for 1 h in a nitrogen atmosphere (30 mL / min), then the background spectrum is collected after the sample cell is cooled to 30°C, and then 5% CO / N is introduced. 2 (30mL / min), and conduct adsorption-desorption infrared test. The test results are shown in Figure 3-Figure 6 .

[0178] XPS test was performed on the platinum-cerium based catalysts prepared in Example 1-Example 2 and Comparative Example 1-Comparative Example 2. The test results of Example 1 and Comparative Example 1 are shown in Figure 7-Figure 8 The test results of Example 2 and Comparative Example 2 are shown in Figure 9-10 .

[0179] The platinum-cerium based catalysts prepared in Example 1 and Comparative Example 1 were subjected to CO 2 Program desorption test, test results see Fig.11 .

[0180] The platinum-cerium based catalysts prepared in Example 2 and Comparative Example 2 were tested by spherical aberration electron microscopy. Figure 12-13 .

[0181] Table 1

[0182] Average size of platinum nanoclusters (nm) <![CDATA[T 50 / ℃]]> <![CDATA[T 100 / ℃]]> <![CDATA[ΔT 50 / ℃]]> Example 1 2.5 117 125 - Example 2 1.8 118 125 1 Example 3 2.4 115 125 - Example 4 2.0 125 135 10 Example 5 2.5 120 127 - Example 6 2.0 131 139 11 Embodiment 11 2.4 122 131 - Example 12 1.5 128 135 - Example 13 - 158 165 30 Embodiment 14 2.5 139 143 - Embodiment 15 - 155 163 - Example 16 2.9 120 131 - Embodiment 17 - 228 240 - Comparative Example 1 1.5 123 130 - Comparative Example 2 - 158 165 35

[0183] Table 2

[0184] Average size of platinum nanoclusters (nm) <![CDATA[T 50 / ℃]]> <![CDATA[T 100 / ℃]]> <![CDATA[ΔT 50 / ℃]]> Example 2 1.8 149 165 26 Example 4 2.0 152 165 23 Example 6 2.0 152 165 23 Example 7 1.9 154 169 21 Example 8 1.8 155 170 20 Example 9 2.0 154 172 21 Example 10 2.2 145 161 30 Example 13 - 175 185 - Comparative Example 2 - 175 185 0 Comparative Example 3 - 350 420 -

[0185] The present invention introduces a surface vacancy regulator into the platinum-cerium-based catalyst to change the alkalinity, oxygen vacancy concentration and cerium vacancy concentration of the cerium-based carrier surface, thereby weakening the strong interaction between the platinum-based redox component and the cerium-based carrier, achieving the stable existence of platinum nanoclusters under high-temperature oxidation treatment conditions, and significantly improving the stability and catalytic activity of the platinum-cerium-based catalyst.

[0186] According to the test results of the conversion rate of catalytic carbon monoxide combustion in Examples 1 to 11, the introduction of the surface vacancy regulator can reduce the Lewis base content and strength on the surface of the cerium-based carrier, increase the surface oxygen vacancy concentration and reduce the cerium vacancy concentration, and weaken the strong interaction between the carrier and the redox component, thereby preparing a cerium-based carrier. Based on the effect of the surface vacancy regulator, after high-temperature calcination, the platinum-based redox component can still maintain a platinum nanocluster distribution, thereby maintaining the original activity.

[0187] According to the test results of the conversion rate of catalytic carbon monoxide combustion of Example 1-Example 2 and Comparative Example 1-Comparative Example 2, if the surface conditioning agent is not introduced, the distribution of platinum nanoclusters cannot be maintained, resulting in a decrease in the activity of the platinum-supported cerium-based catalyst.

[0188] According to the test results of the conversion rate of catalytic carbon monoxide combustion in Example 1 and Example 12-Example 14, the added amount of the surface vacancy regulator should be within an appropriate range. If it is too low, it will not be able to resist the trend of platinum nanoclusters dispersing into single atoms, and if it is too high, a higher concentration of oxygen vacancies will be introduced, inhibiting the cerium-based carrier's ability to activate oxygen.

[0189] According to the test results of the conversion rate of catalytic carbon monoxide combustion in Example 1 and Example 15-Example 16, if the loading amount of the platinum-based redox component is too small, platinum single atoms are easily formed, and if the loading amount is too high, the utilization rate of the platinum atoms is low.

[0190] According to the test results of the conversion rate of catalytic carbon monoxide combustion in Example 1 and Example 17, if the calcination temperature in step (3) is too high, the surface of the platinum nanoclusters will be partially oxidized or dispersed on the surface of the carrier to form single atoms, and the activity will be relatively poor.

[0191] from Figure 3 In the in-situ infrared curves of carbon monoxide in Example 1 and Comparative Example 1, it can be seen that the platinum-cerium-based catalyst prepared in Example 1 has a carbon monoxide concentration of 2050 cm -1 There is an obvious tailing phenomenon in the left and right regions. The peaks in this region can be attributed to the linear adsorption of CO molecules on metallic platinum, indicating that the introduction of Bi is conducive to maintaining the cluster morphology of platinum at 500°C. -1 A symmetrical narrow peak appears, which indicates the linear adsorption of CO molecules on isolated single-atom Pt sites, indicating that Pt atoms are adsorbed on Pt / CeO 2 The surface is atomically dispersed.

[0192] Figure 4-Figure 7It can be seen from the XPS test results that the lattice oxygen ratio of the platinum-cerium-based catalysts prepared in Example 1 and Example 2 is ∼68%, while the lattice oxygen ratio of the platinum-cerium-based catalysts prepared in Comparative Example 1 and Comparative Example 2 is ∼76%, which indicates that the doping of the surface vacancy regulator effectively reduces the strength and content of the base on the carrier surface and the proportion of low-coordinated O, which is beneficial to maintaining the stable distribution of platinum nanoclusters on the surface of the cerium-based carrier.

[0193] from Figure 6 The CO of the cerium-based catalyst prepared in the embodiment and comparative example 1 is shown. 2 It can be seen from the programmed desorption curve that the CO 2 The adsorption capacity is significantly higher than that of the cerium-based catalyst in Comparative Example 1. 2 The adsorption amount is small, and only an obvious signal peak appears at 455℃, which can be attributed to the moderate strength base to CO 2 The desorption peak of the cerium-based catalyst in Comparative Example 1 is obvious at >500°C. For the strong base site, this peak can be attributed to the low-coordinated O on the support surface to CO. 2 The desorption peak further illustrates that the doping of surface vacancy regulator effectively reduces the strength and content of alkali on the support surface and the proportion of low-coordinated O, which is beneficial to maintain the stable distribution of platinum nanoclusters on the surface of the cerium-based support.

[0194] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A platinum-cerium based catalyst, characterized in that The platinum-cerium-based catalyst comprises a cerium-based carrier and a platinum-based redox component distributed on the surface of the cerium-based carrier; The platinum-based redox component includes platinum nanoclusters; The cerium-based support includes a surface vacancy modifier.

2. The platinum-cerium based catalyst according to claim 1, characterized in that The surface vacancy regulator includes an ionic radius ≥ and / or elements with electronegativity ≥ 1.7; Preferably, the surface vacancy modifier comprises any one or a combination of at least two of neodymium, bismuth, tungsten or molybdenum; Preferably, in the cerium-based carrier, the molar percentage of the surface vacancy regulator is 8%-30%, preferably 10%-20%.

3. The platinum-cerium based catalyst according to claim 1 or 2, characterized in that The average size of the platinum nanoclusters is 1 nm-5 nm, preferably 1 nm-3 nm.

4. The platinum-cerium based catalyst according to any one of claims 1 to 3, characterized in that In the platinum-cerium-based catalyst, the mass percentage of the platinum-based reducing component is 0.1%-5%, preferably 0.5%-1%; Preferably, the platinum-based redox component further comprises a second metal; Preferably, the second metal includes any one or a combination of at least two of Pd, Ru or Ir; Preferably, the mass percentage of the second metal is ≤30%.

5. The platinum-cerium based catalyst according to any one of claims 1 to 4, characterized in that The cerium-based support also includes a metal oxide; Preferably, the mass percentage of metal oxide in the cerium-based carrier is ≤20%; Preferably, the metal oxide includes any one of aluminum oxide, manganese dioxide, titanium dioxide, cobalt oxide, nickel oxide or copper oxide, or a combination of at least two thereof.

6. A method for preparing a platinum-cerium based catalyst as claimed in any one of claims 1 to 5, characterized in that: The preparation method comprises: The cerium-based carrier and the platinum-based nanoparticle solution are mixed, dried to obtain a platinum-cerium-based catalyst precursor, and the platinum-cerium-based catalyst precursor is calcined to obtain the platinum-cerium-based catalyst.

7. The preparation method according to claim 6, characterized in that: The preparation method of the cerium-based carrier comprises: Mixing a cerium source, a surface vacancy modifier precursor and a solvent to obtain a mixed solution, reacting to obtain a cerium-based carrier precursor, and calcining the cerium-based carrier precursor to obtain the cerium-based carrier; Preferably, in the mixed solution, the concentrations of the cerium source and the surface vacancy modifier precursor are independently 0.1 mmol / mL-0.5 mmol / mL; Preferably, the molar ratio of the cerium source to the surface vacancy modifier precursor in the mixed solution is (70-92):(8-30); Preferably, the cerium source includes any one of cerium nitrate or cerium chloride or a combination of both; Preferably, the surface vacancy modifier precursor comprises any one or a combination of at least two of neodymium salt, bismuth salt, tungstate or molybdate; Preferably, the surface vacancy modifier precursor includes any one or a combination of at least two of neodymium nitrate, bismuth nitrate, ammonium metatungstate and ammonium molybdate; Preferably, the solvent comprises water and / or ethanol. Preferably, the method for obtaining the cerium-based carrier precursor by the reaction includes any one of a chemical coprecipitation method, a hydrothermal method or a sol-gel method; Preferably, the method for preparing the cerium-based carrier further comprises aging and drying the cerium-based carrier precursor obtained by the reaction; Preferably, the aging temperature is 20°C-40°C; Preferably, the aging time is 4h-12h; Preferably, the drying temperature is 60°C-100°C; Preferably, the temperature for calcining the cerium-based carrier precursor is 500° C.-600° C.; Preferably, the cerium-based carrier precursor is calcined for 3 h to 6 h; Preferably, the heating rate for calcining the cerium-based carrier precursor is 2° C. / min-10° C. / min.

8. The preparation method according to claim 6 or 7, characterized in that: The concentration of platinum-based nanoparticles in the platinum-based nanoparticle solution is 1 mg / mL-3 mg / mL; Preferably, the platinum-based nanoparticles are prepared by reducing a platinum-based precursor; Preferably, the platinum-based precursor comprises a platinum salt and a second metal salt; Preferably, the platinum salt comprises any one or a combination of at least two of platinum nitrate, platinum acetylacetonate, platinum chloride or platinum acetate; Preferably, the second metal salt comprises any one of a Pd salt, a Ru salt or an Ir salt, or a combination of at least two thereof; Preferably, the Pd salt comprises palladium nitrate and / or palladium chloride; Preferably, the Ru salt comprises ruthenium chloride and / or ruthenium acetate; Preferably, the Ir salt includes any one or a combination of at least two of iridium trichloride, ammonium iridate or iridium tetrachloride; Preferably, the method of reducing the platinum-based precursor includes any one of an ethylene glycol reduction method, an ethanol reduction method or a sodium borohydride reduction method.

9. The preparation method according to any one of claims 6 to 8, characterized in that: The method of mixing the cerium-based carrier and the platinum-based nanoparticle solution includes stirring; Preferably, the stirring rate is 300r / min-800r / min; Preferably, the stirring time is 2h-4h; Preferably, the temperature of drying the platinum-cerium based catalyst precursor is 50°C-80°C; Preferably, the temperature for calcining the platinum-cerium based catalyst precursor is 400° C.-600° C.; Preferably, the time for calcining the platinum-cerium based catalyst precursor is 4h-12h; Preferably, the heating rate for calcining the platinum-cerium based catalyst precursor is 2° C. / min-5° C. / min.

10. Use of the platinum-cerium based catalyst according to any one of claims 1 to 5, characterized in that: The platinum-cerium based catalyst is used for catalytic oxidation removal of gaseous pollutants.

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