Preparation method and application of Ga2O3-Al2O3 composite oxide catalyst carrier and catalyst
The preparation of Ga2O3-Al2O3 composite oxide catalyst support by GaAl alloy hydrolysis method solves the problem of uneven oxide mixing, improves the low-temperature activity and high-temperature stability of the catalyst, and is suitable for vehicle exhaust purification.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-09
- Publication Date
- 2026-04-03
AI Technical Summary
Existing technologies make it difficult to achieve uniform mixing of oxides at the nanoscale, resulting in uneven distribution of active sites after noble metal loading, which affects catalytic efficiency. Furthermore, the alumina support collapses and noble metals agglomerate in the motor vehicle exhaust purification system, reducing catalytic activity.
The GaAl alloy is prepared by melting it under an inert gas protection, and then hydrolyzing it in a phosphate buffer solution to generate a hydroxide mixture. Subsequently, it is calcined to form a Ga2O3-Al2O3 composite oxide catalyst support, on which the noble metal Pt is supported. After calcination at different temperatures, a high-performance oxidation catalyst is formed.
The compositional uniformity and structural stability of the Ga2O3-Al2O3 composite oxide catalyst support were achieved, which improved the low-temperature activity and high-temperature stability of the catalyst, enhanced the dispersion uniformity and catalytic activity of precious metals, and made it suitable for vehicle exhaust purification.
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Figure CN121775840A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst material preparation technology, specifically relating to a Ga2O3-Al2O3 composite oxide catalyst support, a method for preparing the catalyst, and its application. Background Technology
[0002] Oxidation catalysts have a wide range of applications. In motor vehicle exhaust purification systems, they oxidize harmful gases such as CO and C3H6 into CO2 and H2O at low temperatures, which are then released into the atmosphere. Therefore, low-temperature, high-activity oxidation catalysts are crucial for oxidizing pollutants emitted during the cold start phase of motor vehicles. On the other hand, the exhaust emission temperature is relatively high under high-speed operating conditions, making high-temperature stability a key indicator for oxidation catalysts.
[0003] Alumina, due to its high specific surface area, is one of the commonly used supports for oxidation catalysts. In motor vehicle exhaust purification systems, the frequent engine operation, high exhaust temperature, and complex composition make the catalyst's tolerance to harsh environments extremely demanding. This leads to the collapse of the alumina structure, the agglomeration of surface-loaded precious metals, and a reduction in catalytic activity.
[0004] To improve the performance of alumina supports, composite oxide supports are often formed by introducing a second oxide component (such as SiO2, TiO2, ZrO2, etc.). However, traditional physical mixing or impregnation methods are difficult to achieve uniform mixing of the two oxides at the nanoscale, resulting in uneven distribution of active sites after noble metal loading, which affects catalytic efficiency.
[0005] It is a known phenomenon that GaAl alloys undergo hydrolysis in aqueous solution to produce hydrogen. However, current research focuses entirely on optimizing alloy composition to improve hydrogen production efficiency. The products are usually regarded as residues that need to be recycled and treated, and there are no reports on their use as precursor materials for preparing high-performance catalyst supports.
[0006] Therefore, developing a novel composite oxide support that can achieve uniform mixing of oxides at the molecular level and has a simple and easy preparation method, and that can be successfully applied in oxidizing catalysts to improve the low-temperature oxidation activity and high-temperature stability of the catalysts, has become an urgent problem to be solved in this field. Summary of the Invention
[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a Ga2O3-Al2O3 composite oxide catalyst support with uniform composition and stable structure. This invention also provides the application of this support in oxidation catalysts.
[0008] The technical solution adopted in this invention is as follows: A Ga2O3-Al2O3 composite oxide catalyst support and a method for preparing the oxidized catalyst, the method steps are as follows: (1) Take a certain amount of gallium and aluminum, and melt them at 400~1000℃ under inert gas protection to prepare GaAl alloy; control the mass ratio of Ga to Al to be 7~8:3~2; (2) Add the GaAl alloy to a phosphate buffer solution with a pH of 7 to 7.5 and carry out a hydrolysis reaction at 30 to 60 °C to obtain a hydroxide mixture; (3) The hydroxide mixture is subjected to solid-liquid separation, washing and drying to obtain the hydroxide precursor; (4) The hydroxide precursor was calcined at 400~600℃ in air atmosphere to obtain the Ga2O3-Al2O3 composite oxide catalyst support.
[0009] Further, the phosphate buffer solution in step (2) is one or more of potassium dihydrogen phosphate (KH2PO4), disodium hydrogen phosphate (Na2HPO4), sodium dihydrogen phosphate (Na2HPO4), and ammonium phosphate ((NH4)3PO4); the concentration of the phosphate buffer solution is 0.1~0.5 mol / L.
[0010] Furthermore, the reaction time of the hydrolysis reaction in step (2) is at least 3 hours; Furthermore, the drying temperature in step (3) is 30~80℃ and the drying time is 3~8h.
[0011] Furthermore, the calcination time of the calcined hydroxide precursor in step (4) is 4-8 hours.
[0012] The method for preparing catalysts using the Ga2O3-Al2O3 composite oxide catalyst support obtained by the above method involves loading noble metal Pt onto Ga2O3-Al2O3 composite oxide and calcining it at 400-600℃ to obtain fresh Pt / (Ga2O3-Al2O3) oxidation catalyst.
[0013] Furthermore, the fresh catalyst was placed in a muffle furnace and calcined at 700-800℃ to obtain an aged Pt / (Ga2O3-Al2O3) oxidation catalyst.
[0014] Furthermore, the loading of the precious metal Pt is 0.1 wt.% to 10 wt.%.
[0015] The application of the oxidized catalyst prepared by this invention is to use the oxidized catalyst for the catalytic oxidation of CO, C3H6, C3H8, and NO.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention utilizes the simultaneous generation of Ga and Al hydroxides during the in-situ hydrolysis of GaAl alloy to achieve uniform mixing of the two components at the nanoscale or even molecular scale. The carrier component has extremely high uniformity, which is something that traditional physical mixing or sequential precipitation methods cannot achieve.
[0017] (2) The catalyst support and catalyst preparation method are simple, the production cost is relatively low, and the reaction conditions are mild (near neutral pH, medium temperature), without the need for expensive raw materials and complex equipment.
[0018] (3) Due to the extremely high uniformity of the carrier components, the carrier has a higher specific surface area (>200 m² / g) and better thermal stability. It has excellent performance and can effectively and stably load noble metal nanoparticles to prevent them from sintering and growing.
[0019] (4) The Pt / (Ga2O3-Al2O3) catalyst has excellent low-temperature activity, which is beneficial to the treatment of exhaust gas emitted during the cold start stage of motor vehicles. It has strong high-temperature thermal stability and better tolerance to the continuous high-temperature operation of motor vehicles at high speed.
[0020] (5) The GaAl alloy hydrolysis technology was creatively applied to the synthesis of high-performance catalyst supports, opening up new application directions for this material system, turning waste into treasure and saving energy. Attached Figure Description
[0021] Figure 1 The X-ray diffraction pattern of the Ga2O3-Al2O3 composite oxide prepared in Example 1 of this invention; Figure 2 This is a scanning electron microscope image of the Ga2O3-Al2O3 composite oxide prepared in Example 1 of the present invention; Figure 3 The EDS spectrum of the Ga2O3-Al2O3 composite oxide prepared in Example 1 of this invention; Figure 4 The oxidation activity curves of Pt / (Ga2O3-Al2O3)-1 oxidizing catalyst prepared in Example 1 of this invention and the comparative example for CO oxidation are shown. Figure 5 The oxidation activity curves of the Pt / (Ga2O3-Al2O3)-1 oxidizing catalyst prepared in Example 1 of this invention and the comparative example of C3H6 are shown. Figure 6 The oxidation activity curves of the Pt / (Ga2O3-Al2O3) oxidizing catalyst prepared in Example 1 of this invention and the comparative example for NO oxidation are shown. Detailed Implementation
[0022] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the embodiments.
[0023] Example 1 A method for preparing a Ga2O3-Al2O3 composite oxide catalyst support, the specific steps of which are as follows: (1) Weigh 8g of gallium particles and 2g of aluminum particles, and melt them at 900℃ under nitrogen protection to prepare Ga8Al2 alloy; (2) Weigh 5g of the above Ga8Al2 alloy powder and add it to 250ml of 0.1mol / L potassium dihydrogen phosphate (KH2PO4) buffer solution with pH=7.5. Place the solution in a 40℃ constant temperature water bath and shake for 3 hours to obtain a white precipitate mixture containing Ga(OH)3 and Al(OH)3. The chemical reaction formula is as follows:
[0024] (3) After the reaction is complete, the white precipitate is centrifuged, washed three times with deionized water and three times with anhydrous ethanol, and dried in an oven at 60°C for 4 hours. (4) Place the dried powder in a muffle furnace and heat it to 600°C at a rate of 5°C / min. Calcine for 5 hours and then cool it with the furnace to obtain the target product Ga2O3-Al2O3 composite oxide carrier.
[0025] The Ga2O3-Al2O3 composite oxide catalyst support obtained in this embodiment has the following characteristics: a specific surface area of 245.138 m². 2 / g, pore volume is 0.164cm³ 3 / g, with a pore size of 4.81nm. Figure 1 The XRD pattern of the Ga2O3-Al2O3 composite oxide carrier product powder obtained in Example 1 is shown. The comparison with the standard γ-Al2O3 PDF and β-Ga2O3 PDF cards proves that the product is a mixture of γ-Al2O and β-Ga2O3. Figure 2 The image shows the product's SEM image, which depicts a stack of sheet-like particles. Figure 3 The EDS spectra of the Ga2O3-Al2O3 composite oxide prepared in this embodiment are shown, representing the energy spectra of C, O, Al and Ga respectively. The presence of carbon, aluminum, oxygen and gallium elements indicates that Ga2O3 and Al2O3 have a very good mixture.
[0026] The Pt / (Ga2O3-Al2O3)-1 oxidation catalyst was prepared using the Ga2O3-Al2O3 composite oxide support prepared in this embodiment. The method steps are as follows: (1) Weigh 4g of Ga2O3-Al2O3 composite oxide and place it in 10ml of water. Stir for 10min to obtain Ga2O3-Al2O3 composite oxide slurry; (2) Add a platinum nitrate solution with a Pt content of 1 wt.% dropwise to the Ga2O3-Al2O3 composite oxide slurry in step (1) above, adjust the pH to 7, and stir continuously for 2 hours to obtain Pt / (Ga2O3-Al2O3)-1; (3) The Pt / (Ga2O3-Al2O3)-1 prepared in step (2) above is dried at 100℃ for 24h, and then placed in a muffle furnace and calcined at 500℃ for 3h to obtain a fresh Pt / (Ga2O3-Al2O3)-1 oxidation catalyst, denoted as Pt / (Ga2O3-Al2O3)-1-F. The fresh Pt / (Ga2O3-Al2O3)-1 oxidation catalyst is placed in a muffle furnace and calcined at 750℃ for 16h to obtain an aged Pt / (Ga2O3-Al2O3) oxidation catalyst, denoted as Pt / (Ga2O3-Al2O3)-1-A.
[0027] (4) The fresh and aged catalysts prepared in step (3) above were tested in a simulated reactor for their oxidation activity against CO, C3H6 and NO. The catalytic activity data are shown in Table 1. Example 2
[0028] A method for preparing a Ga2O3-Al2O3 composite oxide catalyst support, the specific steps of which are as follows: (1) Weigh 7.5g of gallium particles and 2.5g of aluminum particles, and melt them at 1000℃ under nitrogen protection to prepare Ga8Al2 alloy; (2) Weigh 5g of the above alloy powder and add it to 250ml of 0.3mol / L disodium hydrogen phosphate (KH2PO4) buffer solution with pH=7.0. Place it in a constant temperature water bath at 60℃ and shake for 3 hours to obtain a white precipitate mixture containing Ga(OH)3 and Al(OH)3. (3) After the reaction is complete, the white precipitate is centrifuged, washed three times with deionized water and three times with anhydrous ethanol, and dried in an oven at 80°C for 3 hours. (4) Place the dried powder in a muffle furnace and heat it to 400°C at a rate of 5°C / min. Calcine for 8 hours and then cool it with the furnace to obtain the target product Ga2O3-Al2O3 composite oxide carrier.
[0029] The Ga2O3-Al2O3 composite oxide catalyst support obtained in this embodiment has the following characteristics: a specific surface area of 240.159 m². 2 / g, pore volume is 0.160cm³3 / g, with a pore size of 5.23nm, compared with standard γ-Al2O3 PDF and β-Ga2O3 PDF cards, proving that the product is a mixture of γ-Al2O and β-Ga2O3.
[0030] The Pt / (Ga2O3-Al2O3)-2 oxidation catalyst was prepared using the Ga2O3-Al2O3 composite oxide support prepared in this embodiment. The method is as follows: 5g of Ga2O3-Al2O3 composite oxide was weighed and placed in 12ml of water, stirred for 15min to obtain a Ga2O3-Al2O3 composite oxide slurry; then, a platinum nitrate precursor solution with a Pt content of 0.1wt% was added dropwise to the Ga2O3-Al2O3 composite oxide slurry, the pH was adjusted to 7, and stirring was continued for 2h to obtain Pt / (Ga2O3-Al2O3). This was dried at 120℃ for 20h, and then calcined in a muffle furnace at 600℃ for 2.5h to obtain a fresh Pt / (Ga2O3-Al2O3) oxidation catalyst, labeled as Pt / ( The fresh Pt / (Ga2O3-Al2O3) oxidation catalyst was calcined in a muffle furnace at 700℃ for 5 h to obtain the aged Pt / (Ga2O3-Al2O3) oxidation catalyst, labeled as Pt / (Ga2O3-Al2O3)-2-A.
[0031] The fresh and aged catalysts were tested in a simulated reactor to test their oxidation activities for CO, C3H6 and NO. The catalytic activity data are shown in Table 1. Example 3
[0032] A method for preparing a Ga2O3-Al2O3 composite oxide catalyst support, the specific steps of which are as follows: (1) Weigh 7g of gallium particles and 3g of aluminum particles, and melt them at 400℃ under nitrogen protection to prepare Ga7Al3 alloy; (2) Weigh 5g of the above alloy powder and add it to 250mL of sodium dihydrogen phosphate (KH2PO4) buffer solution with pH=7.2. Place it in a constant temperature water bath at 30℃ and shake for 4 hours to obtain a white precipitate mixture containing Ga(OH)3 and Al(OH)3. (3) After the reaction is complete, the white precipitate is centrifuged, washed three times each with deionized water and anhydrous ethanol, and dried in an oven at 30°C for 8 hours. (4) Place the dried powder in a muffle furnace and heat it to 550°C at a rate of 5°C / min. Calcine for 4 hours and then cool it with the furnace to obtain the target product Ga2O3-Al2O3 composite oxide carrier.
[0033] The Ga2O3-Al2O3 composite oxide catalyst support obtained in this embodiment has the following characteristics: a specific surface area of 229.237 m². 2 / g, pore volume is 0.188cm³ 3 / g, with a pore size of 5.35nm, compared with standard γ-Al2O3 PDF and β-Ga2O3 PDF cards, proving that the product is a mixture of γ-Al2O and β-Ga2O3.
[0034] The Pt / (Ga2O3-Al2O3)-3 oxidation catalyst was prepared using the Ga2O3-Al2O3 composite oxide support prepared in this embodiment. The method is as follows: 5g of Ga2O3-Al2O3 composite oxide was weighed and placed in 15ml of water, stirred for 30min to obtain a Ga2O3-Al2O3 composite oxide slurry; then, a platinum nitrate precursor solution with a Pt content of 10wt% was added dropwise to the Ga2O3-Al2O3 composite oxide slurry, the pH was adjusted to 7, and stirring was continued for 2h to obtain Pt / (Ga2O3-Al2O3). This was dried at 150℃ for 18h, and then calcined in a muffle furnace at 400℃ for 5h to prepare a fresh Pt / (Ga2O3-Al2O3) oxidation catalyst, labeled as Pt / ( The fresh Pt / (Ga2O3-Al2O3) oxidation catalyst was calcined in a muffle furnace at 800℃ for 5 h to obtain the aged Pt / (Ga2O3-Al2O3) oxidation catalyst, labeled as Pt / (Ga2O3-Al2O3)-3-A.
[0035] The fresh and aged catalysts were tested in a simulated reactor to test their oxidation activities for CO, C3H6 and NO. The catalytic activity data are shown in Table 1. Example 4
[0036] A method for preparing a Ga2O3-Al2O3 composite oxide catalyst support, the specific steps of which are as follows: (1) Weigh 7g of gallium particles and 2g of aluminum particles, and melt them at 800℃ under nitrogen protection to prepare Ga7Al3 alloy; (2) Weigh 5g of the above alloy powder and add it to 250mL of a buffer solution of sodium dihydrogen phosphate (KH2PO4) and ammonium phosphate ((NH4)3PO4) with pH=7.5. Place it in a constant temperature water bath at 50℃ and shake for 3 hours to obtain a white precipitate mixture containing Ga(OH)3 and Al(OH)3. (3) After the reaction is complete, the white precipitate is centrifuged, washed three times with deionized water and three times with anhydrous ethanol, and dried in an oven at 50°C for 6 hours. (4) Place the dried powder in a muffle furnace, heat it to 500°C, calcine it for 5 hours, and then cool it with the furnace to obtain the target product Ga2O3-Al2O3 composite oxide carrier.
[0037] The Ga2O3-Al2O3 composite oxide catalyst support obtained in this embodiment has the following characteristics: a specific surface area of 231.177 m². 2 / g, pore volume is 0.185cm³ 3 / g, with a pore size of 5.05nm, compared with standard γ-Al2O3 PDF and β-Ga2O3 PDF cards, confirming that the product is a mixture of γ-Al2O and β-Ga2O3.
[0038] The fresh and aged catalysts prepared were tested in a simulated reactor to assess their oxidation activities for CO, C3H6, C3H8, and NO. The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.
[0039] The Pt / (Ga2O3-Al2O3)-3 oxidation catalyst was prepared using the Ga2O3-Al2O3 composite oxide support prepared in this embodiment. The method is as follows: 5g of Ga2O3-Al2O3 composite oxide was weighed and placed in 15ml of water, and stirred for 25min to obtain a Ga2O3-Al2O3 composite oxide slurry; then, a platinum nitrate precursor solution with a Pt content of 2wt% was added dropwise to the Ga2O3-Al2O3 composite oxide slurry, the pH was adjusted to 7, and stirring was continued for 2h to obtain the Pt / (Ga2O3- Al2O3 was dried at 100℃ for 24 hours, and then calcined in a muffle furnace at 550℃ for 5 hours to prepare a fresh Pt / (Ga2O3-Al2O3) oxidation catalyst, labeled Pt / (Ga2O3-Al2O3)-4-F. The fresh Pt / (Ga2O3-Al2O3) oxidation catalyst was then calcined in a muffle furnace at 780℃ for 7 hours to obtain an aged Pt / (Ga2O3-Al2O3) oxidation catalyst, labeled Pt / (Ga2O3-Al2O3)-4-A.
[0040] The fresh and aged catalysts were tested in a simulated reactor to test their oxidation activities for CO, C3H6 and NO. The catalytic activity data are shown in Table 1. Comparative Example
[0041] A commercially available Al2O3 material was used as a support to prepare a Pt / Al2O3 oxidation catalyst. The method was as follows: 4g of Al2O3 composite oxide was weighed and placed in 10ml of water, and stirred for 10min to obtain an Al2O3 slurry. Then, a platinum nitrate precursor solution with a Pt content of 1wt% was added dropwise to the Al2O3 slurry, the pH was adjusted to 7, and the mixture was stirred continuously for 2h to obtain Pt / Al2O3. The Pt / Al2O3 was dried at 100℃ for 24h, and then calcined in a muffle furnace at 500℃ for 3h to obtain a fresh Pt / Al2O3 oxidation catalyst, labeled as Pt / Al2O3-F. The fresh Pt / Al2O3 oxidation catalyst was calcined in a muffle furnace at 750℃ for 16h to obtain an aged Pt / Al2O3 oxidation catalyst, labeled as Pt / Al2O3-A.
[0042] The fresh and aged catalysts were tested in a simulated reactor to test their oxidation activities for CO, C3H6 and NO. The catalytic activity data are shown in Table 1.
[0043] Table 1. Oxidation capacity of the example and comparative oxidation catalysts for CO, THC, and NO in fresh and aged states.
[0044] Note: T50 is the temperature at which the gas conversion efficiency reaches 50%.
[0045] The data in Table 1 show that the oxidation capacity of the examples for CO, C3H6 and NO is better than that of the comparative examples. This indicates that the Ga2O3-Al2O3 composite catalyst support prepared by this invention achieves uniform mixing at the molecular level, and improves the dispersion uniformity of the noble metal Pt on its surface during catalyst preparation, giving it more active sites and thus high activity and stability.
[0046] Figure 4 The oxidation activity curves of Pt / (Ga2O3-Al2O3)-1 oxidizing catalyst prepared in Example 1 of this invention and the comparative example for CO are shown. Figure 5 The oxidation activity curves of the Pt / (Ga2O3-Al2O3)-1 oxidizing catalyst prepared in Example 1 of this invention and the comparative example of C3H6 are shown. Figure 6 The oxidation activity curves of the Pt / (Ga2O3-Al2O3) oxidizing catalyst prepared in Example 1 of this invention and the comparative example for NO oxidation are shown.
[0047] from Figure 4 , Figure 5 , Figure 6Analysis of the activity curves showed that the Pt / Ga2O3-Al2O3-1 oxidation catalyst exhibited a higher catalytic activity in the low-temperature region for the oxidation of CO, C3H6, and NO, demonstrating superior catalytic activity compared to the comparative Pt / Al2O3 catalyst. This also indicates better treatment capability for pollutants emitted during the cold start phase of motor vehicles. After aging, the Pt / Ga2O3-Al2O3 catalyst also showed a higher catalytic activity in the low-temperature region, exhibiting better aging activity than the comparative Pt / Al2O3 catalyst. This demonstrates excellent high-temperature thermal stability and better tolerance to the continuous high-temperature operation conditions during high-speed motor vehicle operation.
[0048] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.
Claims
1. A method for preparing a Ga2O3-Al2O3 composite oxide catalyst support, characterized in that, The steps are as follows: (1) Take a certain amount of gallium and aluminum, and melt them at 400~1000℃ under inert gas protection to prepare GaAl alloy; control the mass ratio of Ga to Al to be 7~8:3~2; (2) Add the GaAl alloy to a phosphate buffer solution with a pH of 7 to 7.5 and carry out a hydrolysis reaction at 30 to 60 °C to obtain a hydroxide mixture; (3) The hydroxide mixture is subjected to solid-liquid separation, washing and drying to obtain the hydroxide precursor; (4) The hydroxide precursor was calcined at 400~600℃ in air atmosphere to obtain the Ga2O3-Al2O3 composite oxide catalyst support.
2. The method for preparing a Ga2O3-Al2O3 composite oxide catalyst support according to claim 1, characterized in that, The phosphate buffer solution in step (2) is one or more of potassium dihydrogen phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, and ammonium phosphate; the concentration of the phosphate buffer solution is 0.1~0.5 mol / L.
3. The method for preparing a Ga2O3-Al2O3 composite oxide catalyst support according to claim 1 or 2, characterized in that, The reaction time for the hydrolysis reaction in step (2) is at least 3 hours.
4. The method for preparing a Ga2O3-Al2O3 composite oxide catalyst support according to claim 1 or 2, characterized in that, The drying temperature in step (3) is 30~80℃ and the drying time is 3~8h.
5. The method for preparing a Ga2O3-Al2O3 composite oxide catalyst support according to claim 1 or 2, characterized in that, The calcination time of the hydroxide precursor in step (4) is 4-8 hours.
6. A method for preparing a catalyst using the Ga2O3-Al2O3 composite oxide catalyst support obtained by the method according to any one of claims 1 to 5, characterized in that, Noble metal Pt was supported on Ga2O3-Al2O3 composite oxide and calcined at 400-600℃ to obtain fresh Pt / (Ga2O3-Al2O3) oxidation catalyst.
7. The method for preparing the catalyst according to claim 6, characterized in that, Fresh catalyst was placed in a muffle furnace and calcined at 700–800°C to obtain aged Pt / (Ga2O3-Al2O3) oxidation catalyst.
8. The method for preparing the catalyst according to claim 6 or 7, characterized in that, The loading of the precious metal Pt is 0.1 wt.% to 10 wt.%.
9. The application of the oxidized catalyst prepared by the method of claim 6, 7 or 8, wherein the oxidized catalyst is used for the catalytic oxidation of CO, C3H6 and NO.