Pt-based catalyst, method for preparing the same, and use thereof

Abstract

The application provides a Pt-based catalyst and a preparation method and application thereof, and belongs to the technical field of environmental catalysis.The Pt-based catalyst comprises a CeO2-CoAlO composite oxide carrier and Pt supported on the surface of the CeO2-CoAlO composite oxide carrier, the mass ratio of the Pt to the CeO2-CoAlO composite oxide carrier is 0.1-1:100, and the mass ratio of CeO2 to CoAlO in the CeO2-CoAlO composite oxide carrier is 1-80:100.CeO2 and CoAlO are compounded as a carrier for CO oxidation, the synergistic effect between the active metal and the carrier is fully exerted, the catalytic activity is improved by adjusting the mass ratio of CeO2 and CoAlO to create effective CeO2-CoAlO interface active sites, and thus the CO oxidation temperature is reduced.

Description

Technical Field

[0001] This invention relates to the field of environmental catalysis technology, and in particular to a Pt-based catalyst, its preparation method, and its application. Background Technology

[0002] To meet higher fuel efficiency standards and lower greenhouse gas emissions, advanced combustion engines are being developed, but their commercial potential depends on whether standard pollutants (carbon monoxide, nitrogen oxides, hydrocarbons, and particulate matter) are controlled to meet emission standards. The lower exhaust temperatures of advanced engines require catalysts to remain active at 150°C to meet future emission regulations. Catalytic oxidation is currently the most direct and effective method for CO treatment, and it is also an important reaction in many industrial processes. Among numerous catalysts, Pt-based noble metal heterogeneous catalysts exhibit excellent CO reactivity. Existing Pt-based noble metal heterogeneous catalysts use either CeO2 or CoAlO as supports, but maintaining activity at 150°C remains challenging. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a Pt-based catalyst, its preparation method, and its application. The Pt-based catalyst of this invention exhibits high catalytic activity and can solve the problem of low CO conversion rate below 150°C.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a Pt-based catalyst, comprising a CeO2-CoAlO composite oxide support and Pt loaded on the surface of the CeO2-CoAlO composite oxide support, wherein the mass ratio of Pt to the CeO2-CoAlO composite oxide support is 0.1 to 1:100, and the mass ratio of CeO2 to CoAlO in the CeO2-CoAlO composite oxide support is 1 to 80:100.

[0006] Preferably, the mass ratio of Pt to CeO2-CoAlO composite oxide support is 0.2 to 0.9:100.

[0007] Preferably, the mass ratio of CeO2 to CoAlO in the CeO2-CoAlO composite oxide support is 5-60:100.

[0008] This invention also provides a method for preparing the Pt-based catalyst described in the above technical solution, comprising the following steps:

[0009] Soluble cobalt salt, soluble aluminum salt, alkaline substance and water are mixed and subjected to hydrothermal reaction and first calcination in sequence to obtain CoAlO oxide;

[0010] The CoAlO oxide, soluble cerium salt and water were mixed and then subjected to a second calcination to obtain CeO2-CoAlO composite oxide support;

[0011] The CeO2-CoAlO composite oxide support was impregnated with a Pt source solution and then subjected to a reduction reaction to obtain the Pt-based catalyst.

[0012] Preferably, the hydrothermal reaction is carried out at a temperature of 80–100°C for a duration of 12–36 hours.

[0013] Preferably, the temperature of the first calcination is 300-900℃, the holding time is 3-8h, and the heating rate from room temperature to the temperature of the first calcination is 1-5℃ / min.

[0014] Preferably, the second calcination temperature is 300–900°C, the holding time is 5–10 h, and the heating rate from room temperature to the second calcination temperature is 1–5°C / min.

[0015] Preferably, the temperature of the reduction reaction is 300-600℃, the holding time is 3-8h, and the heating rate from room temperature to the temperature of the reduction reaction is 1-5℃ / min.

[0016] The present invention also provides the application of the Pt-based catalyst described in the above technical solution or the Pt-based catalyst prepared by the above technical solution in the catalytic oxidation of CO.

[0017] Preferably, the CO catalytic oxidation temperature is 30–220°C, the gas cylinder pressure is 0.1–0.5 MPa, the reaction pressure is atmospheric pressure, and the space velocity is 60,000–80,000 h⁻¹. -1 The volume ratio of the gas components is CO:O2 = 1%~5%:20%~25%, and the mixture is balanced under a protective atmosphere.

[0018] This invention provides a Pt-based catalyst, comprising a CeO2-CoAlO composite oxide support and Pt loaded on the surface of the CeO2-CoAlO composite oxide support, wherein the mass ratio of Pt to the CeO2-CoAlO composite oxide support is 0.1 to 1:100, and the mass ratio of CeO2 to CoAlO in the CeO2-CoAlO composite oxide support is 1 to 80:100.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] This invention utilizes a composite of CeO2 and CoAlO as a support for CO oxidation, fully leveraging the synergistic effect between the active metal and the support. By adjusting the mass ratio of CeO2 to CoAlO, effective CeO2-CoAlO interfacial active sites are created to enhance catalytic activity, thereby lowering the CO oxidation temperature and solving the problem of low CO conversion below 150℃. Furthermore, the CeO2-CoAlO composite oxide support exhibits good dispersibility, effectively reducing the amount of Pt required and lowering catalyst costs, resulting in significant economic benefits.

[0021] This invention also provides a method for preparing Pt-based catalysts by thermal oxidation-reduction. The method is simple, easy to operate, and has good stability. When applied to carbon monoxide oxidation, it exhibits good catalytic activity and has certain prospects for industrial application. Attached Figure Description

[0022] Figure 1 For sample 1 # ~Sample 7 # X-ray diffraction pattern;

[0023] Figure 2 Sample 2 in Example 2 # Sample 6 # Pt / CeO2 and sample 7 # SEM image;

[0024] Figure 3 Sample 2 in Example 2 # TEM-mapping diagram;

[0025] Figure 4 For sample 1 # ~Sample 7 # CO catalytic performance graph;

[0026] Figure 5 For sample 8 # ~Sample 16 # The CO catalytic performance diagram. Detailed Implementation

[0027] This invention provides a Pt-based catalyst comprising a CeO2-CoAlO composite oxide support and Pt loaded on the surface of the CeO2-CoAlO composite oxide support, wherein the mass ratio of Pt to the CeO2-CoAlO composite oxide support is 0.1 to 1:100, and the mass ratio of CeO2 to CoAlO in the CeO2-CoAlO composite oxide support is 1 to 80:100.

[0028] In this invention, the mass ratio of Pt to CeO2-CoAlO composite oxide support is preferably 0.2 to 0.9:100, specifically such as 0.1:100, 0.2:100, 0.3:100, 0.4:100, 0.5:100, 0.6:100, 0.7:100, 0.8:100 or 0.9:100.

[0029] In this invention, the mass ratio of CeO2 to CoAlO in the CeO2-CoAlO composite oxide carrier is 0.1 to 1:100, more preferably 5 to 60:100. In specific embodiments of this invention, such as 1:100, 5:100, 10:100, 15:100, 20:100, 40:100, 60:100 or 80:100.

[0030] The Pt-based catalyst of this invention uses CeO2-CoAlO composite oxide as a support and Pt as the active component. By adjusting the mass ratio of CeO2 and CoAlO, the amount of precious metal Pt can be effectively reduced, thereby achieving high CO conversion efficiency. This fully leverages the synergistic effect between the support and the active component, increases the number of interfacial active sites, and significantly reduces the CO complete conversion temperature.

[0031] This invention also provides a method for preparing the Pt-based catalyst described in the above technical solution, comprising the following steps:

[0032] Soluble cobalt salt, soluble aluminum salt, alkaline substance and water are mixed and subjected to hydrothermal reaction and first calcination in sequence to obtain CoAlO oxide;

[0033] The CoAlO oxide, soluble cerium salt and water were mixed and then subjected to a second calcination to obtain CeO2-CoAlO composite oxide support;

[0034] The CeO2-CoAlO composite oxide support was impregnated with a Pt source solution and then subjected to a reduction reaction to obtain the Pt-based catalyst.

[0035] The present invention prepares the CeO2-CoAlO composite oxide support through the hydrothermal reaction and thermal oxidation, and loads the active component Pt on the support through impregnation and reduction reaction. The preparation method is simple, easy to operate and has good reproducibility.

[0036] The present invention involves mixing soluble cobalt salt, soluble aluminum salt, alkaline substance and water, and then subjecting them to a hydrothermal reaction and a first calcination to obtain CoAlO oxide.

[0037] In this invention, the soluble cobalt salt preferably includes one or more of cobalt chloride, cobalt nitrate, and cobalt sulfate.

[0038] In this invention, the soluble aluminum salt preferably includes one or more of aluminum chloride, aluminum nitrate, and aluminum sulfate.

[0039] In this invention, the molar ratio of cobalt in the soluble cobalt salt to aluminum in the soluble aluminum salt is preferably 3:1 to 1:3.

[0040] In this invention, the alkaline substance is preferably urea, and the urea is preferably added in the form of a urea solution.

[0041] In this invention, the water is preferably distilled water.

[0042] In this invention, the temperature of the hydrothermal reaction is preferably 80-100°C, more preferably 90°C, and the time is preferably 12-36 hours, more preferably 24 hours.

[0043] In this invention, the soluble cobalt salt, soluble aluminum salt, and water are added simultaneously to a reaction vessel, stirred until homogeneous, and then the solution of the alkaline substance is added dropwise while stirring continues.

[0044] The present invention preferably uses a magnetic stirrer for stirring, the stirring speed is preferably 350-550 r / min, and the stirring time is preferably 12-36 h.

[0045] After the hydrothermal reaction is completed, the present invention preferably performs the obtained product by sequential filtration, washing and drying, and then performs the first calcination.

[0046] In this invention, the filtration washing preferably includes washing with water and ethanol in sequence.

[0047] In this invention, the drying temperature is preferably 60°C and the drying time is preferably 12 hours.

[0048] In this invention, the temperature of the first calcination is preferably 300-900°C, more preferably 500-600°C, the holding time is preferably 3-8 hours, more preferably 5-6 hours, and the heating rate from room temperature to the temperature of the first calcination is preferably 1-5°C / min, more preferably 2-4°C / min.

[0049] After obtaining the CoAlO oxide, the present invention mixes the CoAlO oxide, soluble cerium salt and water and then performs a second calcination to obtain CeO2-CoAlO composite oxide support.

[0050] In this invention, the CoAlO oxide is uniformly dispersed in water, and an aqueous solution of soluble cerium salt is added dropwise. The mixture is continuously stirred in a water bath to ensure that the soluble cerium salt is uniformly dispersed on the surface of the CoAlO oxide. This effectively enhances the interaction between the soluble cerium salt molecules and CoAlO. After standing and drying, the mixture is then subjected to the second calcination to obtain the CeO2-CoAlO composite oxide carrier.

[0051] In this invention, the soluble cerium salt preferably includes one or more of cerium nitrate, cerium chloride, and cerium sulfate.

[0052] In this invention, the mass fraction of the aqueous solution of the soluble cerium salt is preferably 1 to 80%, for example, 1 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 40 wt%, 60 wt%, or 80 wt%.

[0053] In this invention, the water bath temperature is preferably 70-90°C, and the time is preferably 1-5 hours, more preferably 2-4 hours.

[0054] In this invention, the temperature of the second calcination is preferably 300-900°C, more preferably 500-600°C, the holding time is preferably 5-10 hours, more preferably 7-8 hours, and the heating rate from room temperature to the temperature of the second calcination is preferably 1-5°C / min, more preferably 2-4°C / min.

[0055] After obtaining the CeO2-CoAlO composite oxide support, the present invention uses a Pt source solution to impregnate the CeO2-CoAlO composite oxide support and then carries out a reduction reaction to obtain the Pt-based catalyst.

[0056] In this invention, the Pt source in the Pt source solution is chloroplatinic acid, platinum nitrate, platinum chloride, or ammonium chloroplatinate.

[0057] In this invention, the temperature of the reduction reaction is preferably 300-600°C, more preferably 400-500°C, the holding time is preferably 3-8 hours, more preferably 5-6 hours, and the heating rate from room temperature to the temperature of the reduction reaction is preferably 1-5°C / min, more preferably 2-4°C / min.

[0058] In this invention, the reduction reaction is preferably carried out under a 10 vol% H2 / Ar atmosphere.

[0059] The present invention also provides the application of the Pt-based catalyst described in the above technical solution or the Pt-based catalyst prepared by the above technical solution in the catalytic oxidation of CO.

[0060] In this invention, the CO catalytic oxidation is preferably the catalytic oxidation treatment of CO-containing automobile exhaust gas or CO-containing industrial flue gas.

[0061] In this invention, the preferred temperature for CO catalytic oxidation is 30–220°C, the preferred cylinder pressure is 0.1–0.5 MPa, more preferably 0.2–0.3 MPa, the preferred reaction pressure is atmospheric pressure, and the preferred space velocity is 60,000–80,000 h⁻¹. -1 The preferred volume ratio of the gas components is CO:O2 = 1%–5%:20%–25%, and it is preferably balanced under a protective atmosphere.

[0062] In this invention, the protective atmosphere is preferably helium, argon or nitrogen.

[0063] In this invention, the function of the gas cylinder pressure is to provide pressure for the flowing gas in the catalytic reaction. Without the gas cylinder pressure, the gas cannot flow through. After entering the reaction device, the pressure needs to be released so that the catalytic reaction can be carried out at atmospheric pressure.

[0064] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0065] This invention utilizes a miniflex 600 powder X-ray diffractometer from Rigaku Corporation of Japan for structural analysis; a CLARA-GHM field emission scanning electron microscope from the Czech Republic for morphological analysis; and a Tecnai G2 S-Twin F20 transmission electron microscope from FEI Corporation of the Netherlands for TEM-mapping elemental distribution analysis.

[0066] Example 1

[0067] Sample 1 # The Pt-based catalyst comprises a support and Pt. The support is a CeO2-CoAlO composite oxide with a CeO2 to CoAlO mass ratio of 80:100. The Pt content is 0.5 wt% of the CeO2-CoAlO composite oxide. The specific preparation steps are as follows:

[0068] 11 g of cobalt nitrate hexahydrate, 5 g of aluminum nitrate nonahydrate, and 30 g of urea were dissolved in 200 mL of distilled water and stirred until dissolved. The solution was then heated and stirred in a water bath at 90 °C for 24 h. The solution was washed with water and ethanol, dried at 60 °C for 12 h, and calcined in air at 500 °C for 4 h at a heating rate of 2 °C / min to obtain CoAlO oxide. The obtained CoAlO powder was then ultrasonically dispersed in 50 mL of distilled water, and 10 mL of cerium nitrate aqueous solution (40 mg / mL) was added dropwise. The solution was then stirred continuously in a water bath at 70 °C for 2 h, dried in an oven at 110 °C for 12 h, and calcined in air at 500 °C for 8 h at a heating rate of 2 °C / min to obtain the product 80CeO2-CoAlO composite oxide. Chloroplatinic acid solution was added dropwise to 50 mL of the uniformly dispersed 80CeO2-CoAlO sample; the sample was reduced at 500 °C for 5 h under a 10 vol% H2 / Ar atmosphere to obtain the final black powder sample. The catalytic reaction conditions were as follows: temperature range of 30–220℃, pressure of 0.2 MPa, and space velocity of 60,000 h⁻¹. -1 Gas composition: CO: 1 vol%, O2: 20 vol%, He equilibrium. The Pt-based catalyst Pt / 80CeO2-CoAlO prepared in this example has the following XRD pattern: Figure 1 As shown.

[0069] Example 2

[0070] Sample 2 # The Pt-based catalyst comprises a support and Pt. The support is a CeO2-CoAlO composite oxide with a CeO2 to CoAlO mass ratio of 60:100. The Pt content is 0.5 wt% of the CeO2-CoAlO composite oxide. The specific preparation steps are as follows:

[0071] 11 g of cobalt nitrate hexahydrate, 5 g of aluminum nitrate nonahydrate, and 30 g of urea were dissolved in 200 mL of distilled water and stirred until dissolved. The solution was then heated and stirred in a water bath at 90 °C for 24 h. The solution was washed with water and ethanol, dried at 60 °C for 12 h, and calcined in air at 500 °C for 4 h at a heating rate of 2 °C / min to obtain CoAlO oxide. The obtained CoAlO powder was then ultrasonically dispersed in 50 mL of distilled water, and 7.5 mL of cerium nitrate aqueous solution (40 mg / mL) was added dropwise. The solution was then stirred continuously in a water bath at 70 °C for 2 h, dried in an oven at 110 °C for 12 h, and calcined in air at 500 °C for 8 h at a heating rate of 2 °C / min to obtain the product 60CeO2-CoAlO composite oxide. Chloroplatinic acid solution was added dropwise to 50 mL of the uniformly dispersed 60CeO2-CoAlO sample; the sample was reduced at 500 °C for 5 h under a 10 vol% H2 / Ar atmosphere to obtain the final black powder sample. The catalytic reaction conditions were as follows: temperature range of 30–220℃, pressure of 0.2 MPa, and space velocity of 60,000 h⁻¹. -1 Gas composition: CO: 1 vol%, O2: 20 vol%, He equilibrium. The Pt-based catalyst Pt / 60CeO2-CoAlO prepared in this example has the following XRD pattern: Figure 1 As shown, the SEM image is as follows: Figure 2 As shown, the TEM-mapping diagram is as follows: Figure 3 As shown.

[0072] Example 3

[0073] Sample 3 # The Pt-based catalyst comprises a support and Pt. The support is a CeO2-CoAlO composite oxide with a CeO2 to CoAlO mass ratio of 40:100. The Pt content is 0.5 wt% of the CeO2-CoAlO composite oxide. The specific preparation steps are as follows:

[0074] 11 g of cobalt nitrate hexahydrate, 5 g of aluminum nitrate nonahydrate, and 30 g of urea were dissolved in 200 mL of distilled water and stirred until dissolved. The solution was then heated and stirred in a water bath at 90 °C for 24 h. The solution was washed with water and ethanol, dried at 60 °C for 12 h, and calcined in air at 500 °C for 4 h at a heating rate of 2 °C / min to obtain CoAlO oxide. The obtained CoAlO powder was then ultrasonically dispersed in 50 mL of distilled water, and 5 mL of cerium nitrate aqueous solution (40 mg / mL) was added dropwise. The solution was then stirred continuously in a water bath at 70 °C for 2 h, dried in an oven at 110 °C for 12 h, and calcined in air at 500 °C for 8 h at a heating rate of 2 °C / min to obtain the product 40CeO2-CoAlO composite oxide. Chloroplatinic acid solution was added dropwise to 50 mL of the uniformly dispersed 40CeO2-CoAlO sample; the sample was reduced at 500 °C for 5 h under a 10 vol% H2 / Ar atmosphere to obtain the final black powder sample. The catalytic reaction conditions were as follows: temperature range of 30–220℃, pressure of 0.2 MPa, and space velocity of 60,000 h⁻¹. -1 Gas composition: CO: 1 vol%, O2: 20 vol%, He equilibrium. The Pt-based catalyst Pt / 40CeO2-CoAlO prepared in this example has the following XRD pattern: Figure 1 As shown.

[0075] Example 4

[0076] Sample 4 was prepared # The Pt-based catalyst comprises a support and Pt. The support is a CeO2-CoAlO composite oxide with a CeO2:CoAlO mass ratio of 20:100. The Pt content is 0.5 wt% of the CeO2-CoAlO composite oxide. The specific preparation steps are as follows:

[0077] 11 g of cobalt nitrate hexahydrate, 5 g of aluminum nitrate nonahydrate, and 30 g of urea were dissolved in 200 mL of distilled water and stirred until dissolved. The solution was then heated and stirred in a water bath at 90 °C for 24 h. The solution was washed with water and ethanol, dried at 60 °C for 12 h, and calcined in air at 500 °C for 4 h at a heating rate of 2 °C / min to obtain CoAlO oxide. The obtained CoAlO powder was then ultrasonically dispersed in 50 mL of distilled water, and 20 mL of cerium nitrate aqueous solution (5 mg / mL) was added dropwise. The solution was then stirred continuously in a water bath at 70 °C for 2 h, dried in an oven at 110 °C for 12 h, and calcined in air at 500 °C for 8 h at a heating rate of 2 °C / min to obtain the product 20CeO2-CoAlO composite oxide. Chloroplatinic acid solution was added dropwise to 50 mL of the uniformly dispersed 20CeO2-CoAlO sample; the sample was reduced at 500 °C for 5 h under a 10 vol% H2 / Ar atmosphere to obtain the final black powder sample. The catalytic reaction conditions were as follows: temperature range of 30–220℃, pressure of 0.2 MPa, and space velocity of 60,000 h⁻¹. -1 Gas composition: CO: 1 vol%, O2: 20 vol%, He equilibrium. The Pt-based catalyst Pt / 20CeO2-CoAlO prepared in this example has the following XRD pattern: Figure 1 As shown.

[0078] Example 5

[0079] Sample 5 # A physical mixed catalyst of Pt / CeO2 and Pt / CoAlO was prepared, with a mass ratio of CeO2 to CoAlO of 60:100 and a Pt content of 0.5 wt% of the total mass of CeO2 and CoAlO. The specific steps are as follows:

[0080] 0.6 g of Pt / CeO2 catalyst (0.5 wt% Pt of CeO2) was physically mixed with 1 g of Pt / CoAlO (0.5 wt% Pt of CoAlO) to obtain the final product. The XRD pattern of the 60Pt / CeO2+Pt / CoAlOmix mixed catalyst prepared in this example is shown in the figure below. Figure 1 As shown.

[0081] Example 6

[0082] Sample 6 # The preparation of Pt supported on CeO2, with Pt content of 0.5 wt% of CeO2, is carried out through the following steps:

[0083] 2g of hydrated cerium nitrate was calcined in a muffle furnace at 500℃ for 5h at a heating rate of 2℃ / min to obtain a CeO2 oxide support. Chloroplatinic acid solution was added dropwise to 50mL of uniformly dispersed CeO2 sample, and the sample was reduced at 500℃ for 5h under a 10vol% H2 / Ar atmosphere to obtain the final yellow powder sample. The catalytic reaction conditions were: temperature range of 30–220℃, pressure of 0.2MPa, and space velocity of 60,000 h⁻¹. -1 Gas composition: CO: 1 vol%, O2: 20 vol%, He equilibrium. The Pt / CeO2 catalyst prepared in this example has the following XRD pattern: Figure 1 As shown.

[0084] Example 7

[0085] Sample 7 was prepared # The preparation of Pt supported on CoAlO, with Pt content of 0.5 wt% of CoAlO, is carried out through the following steps:

[0086] 11 g of cobalt nitrate hexahydrate, 5 g of aluminum nitrate nonahydrate, and 30 g of urea were dissolved in 200 mL of distilled water and stirred. The solution was then heated and stirred in a water bath at 90 °C for 24 h. The solution was washed with water and ethanol, dried at 60 °C for 12 h, and calcined in air at 500 °C for 4 h at a heating rate of 2 °C / min to obtain CoAlO oxide. The CoAlO oxide support was obtained, and chloroplatinic acid solution was added dropwise to 50 mL of uniformly dispersed CoAlO sample. Reduction was carried out at 500 °C for 5 h under a 10 vol% H₂ / Ar atmosphere to obtain the final yellow powder sample. The catalytic reaction conditions were: temperature range of 30–220 °C, pressure of 0.2 MPa, and space velocity of 60,000 h⁻¹. -1 Gas composition: CO: 1 vol%, O2: 20 vol%, He equilibrium. The Pt / CoAlO catalyst prepared in this example has the following XRD pattern: Figure 1 As shown.

[0087] Example 8

[0088] Prepared Sample 8 # The Pt-based catalyst (Pt / 70CeO2-CoAlO) comprises a support and Pt. The support is a CeO2-CoAlO composite oxide with a CeO2:CoAlO mass ratio of 70:100. The Pt content is 0.5 wt% of the CeO2-CoAlO composite oxide. The specific preparation steps are as follows:

[0089] 11 g of cobalt nitrate hexahydrate, 5 g of aluminum nitrate nonahydrate, and 30 g of urea were dissolved in 200 mL of distilled water and stirred until dissolved. The solution was then heated and stirred in a water bath at 90 °C for 24 h. The solution was washed with water and ethanol, dried at 60 °C for 12 h, and calcined in air at 500 °C for 4 h at a heating rate of 2 °C / min to obtain CoAlO oxide. The obtained CoAlO powder was then ultrasonically dispersed in 50 mL of distilled water, and 8.75 mL of cerium nitrate aqueous solution (40 mg / mL) was added dropwise. The solution was then stirred continuously in a water bath at 70 °C for 2 h, dried in an oven at 110 °C for 12 h, and calcined in air at 500 °C for 8 h at a heating rate of 2 °C / min to obtain the product 70CeO2-CoAlO composite oxide. Chloroplatinic acid solution was added dropwise to 50 mL of a uniformly dispersed 70CeO2-CoAlO sample; reduction was carried out at 500 °C for 5 h under a 10 vol% H2 / Ar atmosphere to obtain the final black powder sample. The catalytic reaction conditions were: temperature range of 30–220 °C, pressure of 0.2 MPa, and space velocity of 60,000 h⁻¹. -1 Gas composition: CO: 1 vol%, O2: 20 vol%, He equilibrium.

[0090] Example 9

[0091] Sample 9 was prepared # The Pt-based catalyst (Pt / 50CeO2-CoAlO) comprises a support and Pt. The support is a CeO2-CoAlO composite oxide with a CeO2 to CoAlO mass ratio of 50:100. The Pt content is 0.5 wt% of the CeO2-CoAlO composite oxide. The specific preparation steps are as follows:

[0092] 11 g of cobalt nitrate hexahydrate, 5 g of aluminum nitrate nonahydrate, and 30 g of urea were dissolved in 200 mL of distilled water and stirred until dissolved. The solution was then heated and stirred in a water bath at 90 °C for 24 h. The solution was washed with water and ethanol, dried at 60 °C for 12 h, and calcined in air at 500 °C for 4 h at a heating rate of 2 °C / min to obtain CoAlO oxide. The obtained CoAlO powder was then ultrasonically dispersed in 50 mL of distilled water, and 6.25 mL of cerium nitrate aqueous solution (40 mg / mL) was added dropwise. The solution was then stirred continuously in a water bath at 70 °C for 2 h, dried in an oven at 110 °C for 12 h, and calcined in air at 500 °C for 8 h at a heating rate of 2 °C / min to obtain the product 50CeO2-CoAlO composite oxide. Chloroplatinic acid solution was added dropwise to 50 mL of a uniformly dispersed 50% CeO₂-CoAlO₂ sample; reduction was carried out at 500 °C for 5 h under a 10 vol% H₂ / Ar atmosphere to obtain the final black powder sample. The catalytic reaction conditions were: temperature range of 30–220 °C, pressure of 0.2 MPa, and space velocity of 60,000 h⁻¹. -1 Gas composition: CO: 1 vol%, O2: 20 vol%, He equilibrium.

[0093] Example 10

[0094] Prepare 10 samples # The Pt-based catalyst (Pt / 30CeO2-CoAlO) comprises a support and Pt. The support is a CeO2-CoAlO composite oxide with a CeO2 to CoAlO mass ratio of 30:100. The Pt content is 0.5 wt% of the CeO2-CoAlO composite oxide. The specific preparation steps are as follows:

[0095] 11 g of cobalt nitrate hexahydrate, 5 g of aluminum nitrate nonahydrate, and 30 g of urea were dissolved in 200 mL of distilled water and stirred until dissolved. The solution was then heated and stirred in a water bath at 90 °C for 24 h. The solution was washed with water and ethanol, dried at 60 °C for 12 h, and calcined in air at 500 °C for 4 h at a heating rate of 2 °C / min to obtain CoAlO oxide. The obtained CoAlO powder was then ultrasonically dispersed in 50 mL of distilled water, and 3.75 mL of cerium nitrate aqueous solution (40 mg / mL) was added dropwise. The solution was then stirred continuously in a water bath at 70 °C for 2 h, dried in an oven at 110 °C for 12 h, and calcined in air at 500 °C for 8 h at a heating rate of 2 °C / min to obtain the product 30CeO2-CoAlO composite oxide. Chloroplatinic acid solution was added dropwise to 50 mL of a uniformly dispersed 30CeO2-CoAlO sample; reduction was carried out at 500 °C for 5 h under a 10 vol% H2 / Ar atmosphere to obtain the final black powder sample. The catalytic reaction conditions were: temperature range of 30–220 °C, pressure of 0.2 MPa, and space velocity of 60,000 h⁻¹. -1 Gas composition: CO: 1 vol%, O2: 20 vol%, He equilibrium.

[0096] Example 11

[0097] Sample 11 # The Pt-based catalyst (Pt / 15CeO2-CoAlO) comprises a support and Pt. The support is a CeO2-CoAlO composite oxide with a CeO2 to CoAlO mass ratio of 15:100. The Pt content is 0.5 wt% of the CeO2-CoAlO composite oxide. The specific preparation steps are as follows:

[0098] 11 g of cobalt nitrate hexahydrate, 5 g of aluminum nitrate nonahydrate, and 30 g of urea were dissolved in 200 mL of distilled water and stirred until dissolved. The solution was then heated and stirred in a water bath at 90 °C for 24 h. The solution was washed with water and ethanol, dried at 60 °C for 12 h, and calcined in air at 500 °C for 4 h at a heating rate of 2 °C / min to obtain CoAlO oxide. The obtained CoAlO powder was then ultrasonically dispersed in 50 mL of distilled water, and 15 mL of cerium nitrate aqueous solution (5 mg / mL) was added dropwise. The solution was then stirred continuously in a water bath at 70 °C for 2 h, dried in an oven at 110 °C for 12 h, and calcined in air at 500 °C for 8 h at a heating rate of 2 °C / min to obtain the product 15CeO2-CoAlO composite oxide. Chloroplatinic acid solution was added dropwise to 50 mL of the uniformly dispersed 15CeO2-CoAlO sample; the sample was reduced at 500 °C for 5 h under a 10 vol% H2 / Ar atmosphere to obtain the final black powder sample. The catalytic reaction conditions were as follows: temperature range of 30–220℃, pressure of 0.2 MPa, and space velocity of 60,000 h⁻¹. -1 Gas composition: CO: 1 vol%, O2: 20 vol%, He equilibrium.

[0099] Example 12

[0100] Sample 12 was prepared # The Pt-based catalyst (Pt / 10CeO2-CoAlO) comprises a support and Pt. The support is a CeO2-CoAlO composite oxide with a CeO2 to CoAlO mass ratio of 10:100. The Pt content is 0.5 wt% of the CeO2-CoAlO composite oxide. The specific preparation steps are as follows:

[0101] 11 g of cobalt nitrate hexahydrate, 5 g of aluminum nitrate nonahydrate, and 30 g of urea were dissolved in 200 mL of distilled water and stirred until dissolved. The solution was then heated and stirred in a water bath at 90 °C for 24 h. The solution was washed with water and ethanol, dried at 60 °C for 12 h, and calcined in air at 500 °C for 4 h at a heating rate of 2 °C / min to obtain CoAlO oxide. The obtained CoAlO powder was then ultrasonically dispersed in 50 mL of distilled water, and 10 mL of cerium nitrate aqueous solution (5 mg / mL) was added dropwise. The solution was then stirred continuously in a water bath at 70 °C for 2 h, dried in an oven at 110 °C for 12 h, and calcined in air at 500 °C for 8 h at a heating rate of 2 °C / min to obtain the product 10CeO2-CoAlO composite oxide. Chloroplatinic acid solution was added dropwise to 50 mL of the uniformly dispersed 10CeO2-CoAlO sample; the sample was reduced at 500 °C for 5 h under a 10 vol% H2 / Ar atmosphere to obtain the final black powder sample. The catalytic reaction conditions were as follows: temperature range of 30–220℃, pressure of 0.2 MPa, and space velocity of 60,000 h⁻¹. -1 Gas composition: CO: 1 vol%, O2: 20 vol%, He equilibrium.

[0102] Example 13

[0103] Sample 13 was prepared # The Pt-based catalyst (Pt / 5CeO2-CoAlO) comprises a support and Pt. The support is a CeO2-CoAlO composite oxide with a CeO2 to CoAlO mass ratio of 5:100. The Pt content is 0.5 wt% of the CeO2-CoAlO composite oxide. The specific preparation steps are as follows:

[0104] 11 g of cobalt nitrate hexahydrate, 5 g of aluminum nitrate nonahydrate, and 30 g of urea were dissolved in 200 mL of distilled water and stirred until dissolved. The solution was then heated and stirred in a water bath at 90 °C for 24 h. The solution was washed with water and ethanol, dried at 60 °C for 12 h, and calcined in air at 500 °C for 4 h at a heating rate of 2 °C / min to obtain CoAlO oxide. The obtained CoAlO powder was then ultrasonically dispersed in 50 mL of distilled water, and 5 mL of cerium nitrate aqueous solution (5 mg / mL) was added dropwise. The solution was then stirred continuously in a water bath at 70 °C for 2 h, dried in an oven at 110 °C for 12 h, and calcined in air at 500 °C for 8 h at a heating rate of 2 °C / min to obtain the product 5CeO2-CoAlO composite oxide. Chloroplatinic acid solution was added dropwise to 50 mL of the uniformly dispersed 5CeO2-CoAlO sample; the sample was reduced at 500 °C for 5 h under a 10 vol% H2 / Ar atmosphere to obtain the final black powder sample. The catalytic reaction conditions were as follows: temperature range of 30–220℃, pressure of 0.2 MPa, and space velocity of 60,000 h⁻¹. -1 Gas composition: CO: 1 vol%, O2: 20 vol%, He equilibrium.

[0105] Example 14

[0106] Sample 14 was prepared # The Pt-based catalyst (Pt / 1CeO2-CoAlO) comprises a support and Pt. The support is a CeO2-CoAlO composite oxide with a CeO2 to CoAlO mass ratio of 1:100. The Pt content is 0.5 wt% of the CeO2-CoAlO composite oxide. The specific preparation steps are as follows:

[0107] 11 g of cobalt nitrate hexahydrate, 5 g of aluminum nitrate nonahydrate, and 30 g of urea were dissolved in 200 mL of distilled water and stirred until dissolved. The solution was then heated and stirred in a water bath at 90 °C for 24 h. The solution was washed with water and ethanol, dried at 60 °C for 12 h, and calcined in air at 500 °C for 4 h at a heating rate of 2 °C / min to obtain CoAlO oxide. The obtained CoAlO powder was then ultrasonically dispersed in 50 mL of distilled water, and 1 mL of cerium nitrate aqueous solution (5 mg / mL) was added dropwise. The solution was then stirred continuously in a water bath at 70 °C for 2 h, dried in an oven at 110 °C for 12 h, and calcined in air at 500 °C for 8 h at a heating rate of 2 °C / min to obtain the product 1CeO2-CoAlO composite oxide. Chloroplatinic acid solution was added dropwise to 50 mL of the uniformly dispersed 1CeO2-CoAlO sample; the sample was reduced at 500 °C for 5 h under a 10 vol% H2 / Ar atmosphere to obtain the final black powder sample. The catalytic reaction conditions were as follows: temperature range of 30–220℃, pressure of 0.2 MPa, and space velocity of 60,000 h⁻¹.-1 Gas composition: CO: 1 vol%, O2: 20 vol%, He equilibrium.

[0108] Example 15

[0109] Prepare 15 samples # The Pt-based catalyst comprises a support and Pt. The support is a CeO2-CoAlO composite oxide with a CeO2:CoAlO mass ratio of 60:100. The Pt content is 0.1 wt% of the CeO2-CoAlO composite oxide. The specific preparation steps are as follows:

[0110] 11 g of cobalt nitrate hexahydrate, 5 g of aluminum nitrate nonahydrate, and 30 g of urea were dissolved in 200 mL of distilled water and stirred until dissolved. The solution was then heated and stirred in a water bath at 90 °C for 24 h. The solution was washed with water and ethanol, dried at 60 °C for 12 h, and calcined in air at 500 °C for 4 h at a heating rate of 2 °C / min to obtain CoAlO oxide. The obtained CoAlO powder was then ultrasonically dispersed in 50 mL of distilled water, and 7.5 mL of cerium nitrate aqueous solution (40 mg / mL) was added dropwise. The solution was then stirred continuously in a water bath at 70 °C for 2 h, dried in an oven at 110 °C for 12 h, and calcined in air at 500 °C for 8 h at a heating rate of 2 °C / min to obtain the product 60CeO2-CoAlO composite oxide. Chloroplatinic acid solution was added dropwise to 50 mL of the uniformly dispersed 60CeO2-CoAlO sample; the sample was reduced at 500 °C for 5 h under a 10 vol% H2 / Ar atmosphere to obtain the final black powder sample. The catalytic reaction conditions were as follows: temperature range of 30–220℃, pressure of 0.2 MPa, and space velocity of 60,000 h⁻¹. -1 Gas composition: CO: 1 vol%, O2: 20 vol%, He equilibrium.

[0111] Example 16

[0112] Sample 16 was prepared # The Pt-based catalyst comprises a support and Pt. The support is a CeO2-CoAlO composite oxide with a CeO2 to CoAlO mass ratio of 60:100. The Pt content is 1 wt% of the CeO2-CoAlO composite oxide. The specific preparation steps are as follows:

[0113] 11 g of cobalt nitrate hexahydrate, 5 g of aluminum nitrate nonahydrate, and 30 g of urea were dissolved in 200 mL of distilled water and stirred until dissolved. The solution was then heated and stirred in a water bath at 90 °C for 24 h. The solution was washed with water and ethanol, dried at 60 °C for 12 h, and calcined in air at 500 °C for 4 h at a heating rate of 2 °C / min to obtain CoAlO oxide. The obtained CoAlO powder was then ultrasonically dispersed in 50 mL of distilled water, and 7.5 mL of cerium nitrate aqueous solution (40 mg / mL) was added dropwise. The solution was then stirred continuously in a water bath at 70 °C for 2 h, dried in an oven at 110 °C for 12 h, and calcined in air at 500 °C for 8 h at a heating rate of 2 °C / min to obtain the product 60CeO2-CoAlO composite oxide. Chloroplatinic acid solution was added dropwise to 50 mL of the uniformly dispersed 60CeO2-CoAlO sample; the sample was reduced at 500 °C for 5 h under a 10 vol% H2 / Ar atmosphere to obtain the final black powder sample. The catalytic reaction conditions were as follows: temperature range of 30–220℃, pressure of 0.2 MPa, and space velocity of 60,000 h⁻¹. -1 Gas composition: CO: 1 vol%, O2: 20 vol%, He equilibrium.

[0114] Example 17

[0115] Characterization of sample structure, morphology and elemental distribution

[0116] Sample 1 was examined using powder X-rays. # ~Sample 7 # Perform structural analysis, such as Figure 1 As shown, the results indicate that all synthesized samples are cubic CeO2 phase and spinel CoAlO phase. Sample 1 # Sample 4 # The composite structure of the two was further verified by XRD. Sample 2 was analyzed by SEM. # Sample 6 # and sample 7 # The morphology was characterized. For example... Figure 2 As shown, sample 7 # Sample 6 has a nanosheet structure. # Sample 2 has a nanosphere morphology. # As a result of the combination of the two, most of the nanoparticles are distributed on the surface of the nanosheets, with a small portion distributed outside the nanosheets. Sample 2 was analyzed using TEM-mapping. # The distribution of each element was characterized, such as Figure 3 As shown, Co, Al, Ce, and O are uniformly dispersed, indicating that they are well composited. At the same time, Pt is also uniformly distributed on the carrier surface, showing good dispersion.

[0117] Example 18 Carbon monoxide oxidation performance test

[0118] The Pt-based catalyst prepared in the examples was loaded into a U-shaped tube and placed in a reactor for heating at different temperatures to test its performance. The gas produced after the reaction was primarily detected by gas chromatography equipped with a TCD detector to evaluate its activity.

[0119] Sample 1 # ~Sample 7 # The performance graphs of the obtained catalysts at different temperatures for CO conversion are shown in the figure below. Figure 4 As shown, sample 8 # ~Sample 16 # The performance graphs of the obtained catalysts at different temperatures for CO conversion are shown in the figure below. Figure 5 As shown, sample 2 # Complete CO conversion can be achieved at 100℃, and the widest operating temperature window of 100~220℃ can be maintained.

[0120] The preparation parameters of the Pt-based composite materials obtained in the above embodiments and the corresponding CO complete conversion temperature and temperature window range test results are listed in Table 1. From Table 1, the following points can be drawn:

[0121] (1) When the Pt loading is only 0.5 wt%, sample 2 # Complete CO removal is achieved at 100℃, making it suitable for automotive exhaust treatment or industrial flue gas catalysis, with high economic benefits;

[0122] (2) When the mass ratio of CeO2 to CoAlO is 60:100, the number of interfacial active sites is effectively increased compared to samples 5 physically mixed in the same proportion. # This effectively reduced the complete CO conversion temperature from 160℃ to 100℃, indicating that the CeO2-CoAlO supported Pt-based catalyst prepared by the thermal oxidation-reduction method has strong interfacial interactions, which is beneficial for dispersing and anchoring Pt species and increasing the density of active sites.

[0123] Sample 2 # Compared to other comparative samples, it has the widest CO complete conversion temperature window (100~220℃), effectively expanding the purification window for automobile exhaust and making it suitable for large-scale industrial production.

[0124] Table 1. Preparation parameters, CO complete conversion temperature, and temperature window range test results of Pt-based composite materials.

[0125]

[0126]

[0127] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A Pt-based catalyst, characterized in that, The invention includes a CeO2-CoAlO composite oxide support and Pt loaded on the surface of the CeO2-CoAlO composite oxide support, wherein the mass ratio of Pt to CeO2-CoAlO composite oxide support is 0.2~0.9:100, and the mass ratio of CeO2 to CoAlO in the CeO2-CoAlO composite oxide support is 30~80:100 or 1~15:

100. The preparation method of the Pt-based catalyst includes the following steps: Soluble cobalt salt, soluble aluminum salt, alkaline substance and water are mixed and subjected to hydrothermal reaction and first calcination in sequence to obtain CoAlO oxide; The CoAlO oxide, soluble cerium salt and water were mixed and then subjected to a second calcination to obtain CeO2-CoAlO composite oxide support; The CeO2-CoAlO composite oxide support was impregnated with a Pt source solution and then subjected to a reduction reaction to obtain the Pt-based catalyst.

2. The method for preparing the Pt-based catalyst according to claim 1, characterized in that, Includes the following steps: Soluble cobalt salt, soluble aluminum salt, alkaline substance and water are mixed and subjected to hydrothermal reaction and first calcination in sequence to obtain CoAlO oxide; The CoAlO oxide, soluble cerium salt and water were mixed and then subjected to a second calcination to obtain CeO2-CoAlO composite oxide support; The CeO2-CoAlO composite oxide support was impregnated with a Pt source solution and then subjected to a reduction reaction to obtain the Pt-based catalyst.

3. The preparation method according to claim 2, characterized in that, The hydrothermal reaction is carried out at a temperature of 80~100℃ for a time of 12~36h.

4. The preparation method according to claim 2, characterized in that, The temperature of the first calcination is 300~900℃, the holding time is 3~8h, and the heating rate from room temperature to the temperature of the first calcination is 1~5℃ / min.

5. The preparation method according to claim 2, characterized in that, The second calcination temperature is 300~900℃, the holding time is 5~10h, and the heating rate from room temperature to the second calcination temperature is 1~5℃ / min.

6. The preparation method according to claim 2, characterized in that, The reduction reaction is carried out at a temperature of 300~600℃ for 3~8h, and the heating rate from room temperature to the temperature of the reduction reaction is 1~5℃ / min.

7. The application of the Pt-based catalyst according to claim 1 or the Pt-based catalyst prepared by any one of claims 2 to 6 in the catalytic oxidation of CO.

8. The application according to claim 7, characterized in that, The CO catalytic oxidation was carried out at a temperature of 30–220 °C, a gas cylinder pressure of 0.1–0.5 MPa, a reaction pressure of atmospheric pressure, and a space velocity of 60,000–80,000 h⁻¹. -1 The volume ratio of the gas components is CO:O2 = 1%~5%:20%~25%, and equilibrium is achieved using a protective atmosphere.

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