Supported Pt-based catalyst as well as preparation method and application thereof
By loading NiO additive on cordierite carrier, a highly dispersed small-sized Pt-based catalyst was prepared, which solved the problem of low Pt dispersion and achieved high activity and stability of the catalyst, making it suitable for low-temperature oxidation of formaldehyde.
Patent Information
- Application Number
- CN202510776542.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-11
- Publication Date
- 2025-10-10
AI Technical Summary
The existing Pt catalyst supported on the cordierite carrier has the problem of low Pt dispersion, resulting in low catalytic activity and stability.
NiO is used as an auxiliary agent. By loading Pt and NiO on a cordierite carrier, a highly dispersed small-sized supported Pt-based catalyst is prepared. The method includes the steps of mixed metal oxide calcination, impregnation, drying, calcination and reduction.
The dispersion of Pt on the cordierite carrier is improved, and the low-temperature activity and stability of the catalyst are significantly enhanced, making it suitable for the efficient catalytic oxidation of formaldehyde.
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Figure CN120754868A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of catalysts, and in particular to a supported Pt-based catalyst and a preparation method and application thereof. Background Art
[0002] Formaldehyde (HCHO) is a typical volatile organic compound (VOC), which is mainly released from furniture, textiles and building materials. According to the classification of the International Agency for Research on Cancer (IARC), formaldehyde is identified as a Class I carcinogen. Even if the formaldehyde concentration is as low as the ppm level, long-term exposure to formaldehyde can cause great harm to human health, such as irritation to the eyes and skin, asthma and even cancer. Therefore, the effective removal of formaldehyde is very important for protecting human health. At present, the main technologies for removing formaldehyde include adsorption, photocatalytic oxidation, plasma catalytic oxidation and thermal catalytic oxidation. Among them, the oxidation of formaldehyde into CO2 and water that are harmless to human health through thermal catalytic oxidation is recognized as one of the most effective and promising methods for formaldehyde removal. The key to this technology lies in the preparation of high-performance catalysts.
[0003] Currently, there are two major categories of catalysts used for HCHO catalytic oxidation: one is transition metal oxide catalysts and the other is supported precious metal catalysts. Although transition metal oxide catalysts (such as CeO2, MnO2, CoO x ) have the advantage of low cost, but their HCHO oxidation activity is far lower than that of precious metal catalysts (such as Pt, Pd, Ag, Ru, and Rh). Among precious metal catalysts, Pt-based catalysts are considered one of the most ideal catalysts for catalyzing formaldehyde oxidation due to their high activity in the formaldehyde oxidation reaction. For example, based on the formaldehyde oxidation performance of different precious metal catalysts reported in the literature under the same reaction conditions, the order of catalytic activity is Pt / TiO2>>Rh / TiO2>Pd / TiO2>Au / TiO2 [Catalytic Today, 2007, 126, 345-350].
[0004] Selecting a suitable carrier is key to achieving excellent formaldehyde oxidation activity for supported Pt catalysts. Numerous formaldehyde oxidation catalyst carriers have been reported in the literature, including active carriers such as CeO2, TiO2, and Co3O4, as well as inert carriers such as SiO2, Al2O3, and MgO. This also includes the use of Pt catalysts supported on cordierite carriers for the catalytic oxidation of formaldehyde. Cordierite has significant advantages such as high temperature resistance, low thermal expansion coefficient, and good chemical stability. However, existing Pt catalysts supported on cordierite carriers suffer from low Pt dispersion, resulting in low overall catalytic activity and stability. Therefore, to address these issues, we propose a supported Pt-based catalyst, its preparation method, and its application. Summary of the Invention
[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a supported Pt-based catalyst and a preparation method and application thereof.
[0006] In order to achieve the above object, the present invention adopts the following technical solutions:
[0007] A supported Pt-based catalyst comprises Pt, NiO and a cordierite carrier, wherein the Pt and NiO are supported on the cordierite carrier.
[0008] Preferably, the cordierite carrier structure is Mg 2-a X a Al4Si5O 18 , X is one or more of Fe, Mn and Ni, wherein 0≤a≤1, and when a is 0, the general structure formula of the cordierite support is Mg2Al4Si5O 18 .
[0009] Preferably, the mass ratio of Ni to Pt is 9:1.
[0010] A purification device provided with a supported Pt-based catalyst.
[0011] Preferably, the purification device is used to purify formaldehyde.
[0012] A method for preparing a supported Pt-based catalyst comprises the following steps:
[0013] Step 1: MgO, SiO2, Al2O3 and one or more metal oxides of Fe, Mn and Ni are mixed, ground and calcined to obtain a cordierite support;
[0014] Step 2: Immerse the cordierite support in a mixed solution of Pt precursor and Ni salt, stir, stand for aging, dry and then calcine, and then wash, dry and reduce to obtain a highly dispersed small-sized Pt-based catalyst.
[0015] The Pt precursor is one or more of chloride, nitrate, acetate, or acetylacetonate; and the Ni salt is one or more of chloride, nitrate, acetate, or sulfate.
[0016] The invention discloses an application of a supported Pt-based catalyst in the catalytic oxidation reaction of HCHO.
[0017] Preferably, in the HCHO catalytic oxidation reaction, the concentration of HCHO is 0-500 ppm (excluding 0).
[0018] Preferably, in the HCHO catalytic oxidation reaction, the space velocity is 0-100000 mL / (gh) and does not include 0.
[0019] Compared with the prior art, the present invention has the following beneficial effects:
[0020] The present invention mixes MgO, SiO2, Al2O3, and one or more metal oxides including Fe, Mn, and Ni, grinds, and calcines to produce a cordierite support. The cordierite support is then impregnated with a mixed solution of a Pt precursor and a Ni salt. After drying, the support is calcined, washed, dried, and reduced to produce a highly dispersed, small-sized supported Pt-based catalyst. This simple and easy-to-control method demonstrates high low-temperature activity and ultrahigh stability in the HCHO catalytic oxidation reaction. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0022] Figure 1 The 9NiO-1Pt / Mg2Al4Si5O 18 and 1Pt / Mg2Al4Si5O 18 High-resolution scanning transmission electron microscopy images.
[0023] Figure 2 9NiO-1Pt / Mg2Al4Si5O 18 、6NiO-1Pt / Mg2Al4Si5O 18 、12NiO-1Pt / Mg2Al4Si5O 18 and 1Pt / Mg2Al4Si5O 18 The catalytic oxidation activity results in the formaldehyde oxidation reaction under the conditions of relative humidity of 25%, formaldehyde concentration of 150 ppm and space velocity of 30000 mL / (gh).
[0024] Figure 3 9NiO-1Pt / Mg2Al4Si5O 18 、6NiO-1Pt / Mg2Al4Si5O 18 、12NiO-1Pt / Mg2Al4Si5O 18 and 1Pt / Mg2Al4Si5O 18 Stability results in the formaldehyde catalytic oxidation reaction at 60°C, 25% relative humidity, 150 ppm formaldehyde concentration, and 30,000 mL / (gh) space velocity. DETAILED DESCRIPTION
[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0026] The present invention discloses a method for preparing a supported Pt-based catalyst, comprising the following steps:
[0027] Step 1: Mix magnesium oxide, silicon dioxide, aluminum oxide and metal oxides of other elements, grind them, and then calcine them at 900-1500°C for 1-10 hours to obtain a cordierite carrier;
[0028] Step 2: Immerse the cordierite support in a mixed solution of a Pt precursor and a Ni salt, stir for 0.5 to 2 hours, allow to age for 1 to 24 hours, dry at 60-120°C for 2 to 24 hours, calcine at 300-700°C for 1 to 8 hours, then wash, dry at 60-120°C for 2 to 24 hours, and then reduce with hydrogen at 100-250°C for 15 to 120 minutes to obtain a highly dispersed, small-sized supported Pt-based catalyst with a Pt weight percentage of 0.2-5wt.% and a Ni weight percentage of 1-15wt.%.
[0029] More specific embodiments and comparative examples are disclosed below to illustrate the technical solutions of the present invention.
[0030] Practical Example 1 9NiO-1Pt / Mg2Al4Si5O 18
[0031] 8.0610 g of magnesium oxide (MgO), 30.0430 g of silicon dioxide (SiO2), and 20.3930 g of aluminum oxide (Al2O3) were weighed and mixed. The mixture was calcined at 1200° C. for 3 hours and ground into powder to obtain a cordierite carrier.
[0032] 0.1638 g of chloroplatinic acid solution (1 g of chloroplatinic acid contains 0.1233 g of Pt), 0.9817 g of nickel nitrate hexahydrate and deionized water were poured into a beaker, stirred for 5 minutes and then ultrasonicated for 5 minutes. 2 g of Mg2Al4Si5O was added to the solution. 18 , stirred for 30 minutes, and allowed to stand for 24 hours; dried at 60°C for 12 hours, and calcined in a muffle furnace at 500°C for 5 hours; the product was washed after cooling, dried at 120°C for 12 hours, and finally reduced with 5 vol% H2 / N2 at 200°C for 30 minutes to obtain a Pt catalyst with a nickel content of 9 wt.% and a Pt content of 1 wt.%, named 9NiO-1Pt / Mg2Al4Si5O18 Catalyst: 9NiO-1Pt / Mg2Al4Si5O 18 High-resolution scanning transmission electron microscopy images of the catalysts are shown in Figure 2. Figure 1 (a) As shown. In this example, 9NiO-1Pt / Mg2Al4Si5O 18 The Pt dispersion in the catalyst was 83%, as measured by hydrogen pulse adsorption at 50°C using a Micromeritics AutoChem II 2920 instrument. The weight percentage of Pt in the catalyst prepared in this example was 1 wt.%, and the weight percentage of Ni was 9 wt.%, as measured using an Agilent 5110 inductively coupled plasma spectrometer.
[0033] 9NiO-1Pt / Mg2Al4Si5O 18 The performance evaluation of the catalyst was carried out in a fixed bed reactor. 0.1 g of catalyst was weighed and loaded into the fixed bed reactor. The 9NiO-1Pt / Mg2Al4Si5O 18 The activity and stability of the catalyst at different temperatures were measured under conditions of 25% relative humidity, 150 ppm formaldehyde concentration, and a space velocity of 30,000 mL / (gh). All reactions were conducted at atmospheric pressure. The stability test was conducted at 60°C.
[0034] 9NiO-1Pt / Mg2Al4Si5O 18 The HCHO conversion results of the catalyst are as follows Figure 2 As shown, the stability Figure 3 shown.
[0035] Practical Example 2 6NiO-1Pt / Mg2Al4Si5O 18
[0036] 8.0610 g of magnesium oxide (MgO), 30.0430 g of silicon dioxide (SiO2), and 20.3930 g of aluminum oxide (Al2O3) were weighed and mixed. The mixture was calcined at 1200° C. for 3 hours and ground into powder to obtain a cordierite carrier.
[0037] 0.1638 g of chloroplatinic acid solution (1 g of chloroplatinic acid contains 0.1233 g of Pt), 0.6326 g of nickel nitrate hexahydrate and deionized water were poured into a beaker, stirred for 5 minutes and then ultrasonicated for 5 minutes. 2 g of Mg2Al4Si5O was added to the solution. 18, stirred for 30 minutes, and allowed to stand for 24 hours; dried at 60°C for 12 hours, and calcined in a muffle furnace at 500°C for 5 hours; the product was washed after cooling, dried at 120°C for 12 hours, and finally reduced with 5 vol% H2 / N2 at 200°C for 30 minutes to obtain a Pt catalyst with a nickel content of 6 wt.% and a Pt content of 1 wt.%, named 6NiO-1Pt / Mg2Al4Si5O 18 Catalyst. This example prepared 6NiO-1Pt / Mg2Al4Si5O 18 The dispersion of Pt in the catalyst is 77%, which is measured by hydrogen pulse adsorption at 50°C using a Micromeritics AutoChem II 2920 instrument. 18 The weight percentage of Pt in the catalyst is 1 wt.%, and the weight percentage of Ni is 6 wt.%, which are obtained by detection using an Agilent 5110 inductively coupled plasma spectrometer.
[0038] 6NiO-1Pt / Mg2Al4Si5O 18 The performance evaluation of the catalyst was carried out in a fixed bed reactor. 0.1 g of catalyst was weighed and loaded into the fixed bed reactor. The 6NiO-1Pt / Mg2Al4Si5O 18 The activity and stability of the catalyst at different temperatures were measured under conditions of 25% relative humidity, 150 ppm formaldehyde concentration, and a space velocity of 30,000 mL / (gh). All reactions were conducted at atmospheric pressure. The stability test was conducted at 60°C.
[0039] 6NiO-1Pt / Mg2Al4Si5O 18 The HCHO conversion results of the catalyst are as follows Figure 2 As shown, the stability Figure 3 shown.
[0040] Practical Example 3 12NiO-1Pt / Mg2Al4Si5O 18
[0041] 8.0610 g of magnesium oxide (MgO), 30.0430 g of silicon dioxide (SiO2), and 20.3930 g of aluminum oxide (Al2O3) were weighed and mixed. The mixture was calcined at 1200° C. for 3 hours and ground into powder to obtain a cordierite carrier.
[0042] Pour 0.1638 g of chloroplatinic acid solution (1 g of chloroplatinic acid contains 0.1233 g of Pt), 1.3511 g of nickel nitrate hexahydrate and deionized water into a beaker, stir for 5 minutes and then ultrasonicate for 5 minutes. Add 2 g of Mg2Al4Si5O 18, stirred for 30 minutes, and allowed to stand for 24 hours; dried at 60°C for 12 hours, and calcined in a muffle furnace at 500°C for 5 hours; the product was washed after cooling, dried at 120°C for 12 hours, and finally reduced with 5 vol% H2 / N2 at 200°C for 30 minutes to obtain a Pt catalyst with a nickel content of 12 wt.% and a Pt content of 1 wt.%, named 12NiO-1Pt / Mg2Al4Si5O 18 Catalyst. This example prepared 12NiO-1Pt / Mg2Al4Si5O 18 The weight percentage of Pt in the catalyst is 1 wt.%, and the weight percentage of Ni is 12 wt.%, which are obtained by detection using an Agilent 5110 inductively coupled plasma spectrometer.
[0043] 12NiO-1Pt / Mg2Al4Si5O 18 The performance evaluation of the catalyst was carried out in a fixed bed reactor. 0.1 g of catalyst was weighed and loaded into the fixed bed reactor. The 12NiO-1Pt / Mg2Al4Si5O 18 The activity and stability of the catalyst at different temperatures were measured under conditions of 25% relative humidity, 150 ppm formaldehyde concentration, and a space velocity of 30,000 mL / (gh). All reactions were conducted at atmospheric pressure. The stability test was conducted at 60°C.
[0044] 12NiO-1Pt / Mg2Al4Si5O 18 The HCHO conversion results of the catalyst are as follows Figure 2 As shown, the stability Figure 3 shown.
[0045] Practical Example 4 9NiO-1Pt / Mg 1.14 Fe 0.86 Al4Si5O 18
[0046] Weigh 4.5950 g of magnesium oxide (MgO), 34.7450 g of ferric nitrate nonahydrate (Fe(NO3)3.9H2O), 20.3920 g of aluminum oxide (Al2O3), and 30.0430 g of silicon dioxide (SiO2), mix them, calcine the mixture at 1200°C for 3 hours, grind it into powder, and obtain a cordierite carrier.
[0047] 0.1638 g of chloroplatinic acid solution (1 g of chloroplatinic acid contains 0.1233 g of Pt), 0.9817 g of nickel nitrate hexahydrate and deionized water were poured into a beaker, stirred for 5 minutes and then ultrasonicated for 5 minutes. 2 g of Mg was added to the solution. 1.14 Fe 0.86 Al4Si5O 18, stirred for 30 minutes, and allowed to stand for 24 hours; dried at 60°C for 12 hours, and calcined in a muffle furnace at 500°C for 5 hours; the product was washed after cooling, dried at 120°C for 12 hours, and finally reduced with 5 vol% H2 / N2 at 200°C for 30 minutes to obtain a Pt catalyst with a nickel content of 9wt.% and a Pt content of 1wt.%, named 9NiO-1Pt / Mg 1.14 Fe 0.86 Al4Si5O 18 Catalyst. This example prepared 9NiO-1Pt / Mg 1.14 Fe 0.86 Al4Si5O 18 The weight percentage of Pt in the catalyst is 1 wt.%, and the weight percentage of Ni is 9 wt.%, and these data are obtained by detection using an Agilent 5110 inductively coupled plasma spectrometer.
[0048] 9NiO-1Pt / Mg 1.14 Fe 0.86 Al4Si5O 18 The performance test and evaluation of the catalyst were carried out in a fixed bed reactor. 0.1 g of catalyst was weighed and loaded into the fixed bed reactor. The 9NiO-1Pt / Mg 1.14 Fe 0.86 Al4Si5O 18 The activity of the catalyst at different temperatures under normal pressure, relative humidity of 25%, formaldehyde concentration of 150ppm, and space velocity of 30000mL / (gh) was obtained. 1.14 Fe 0.86 Al4Si5O 18 The HCHO conversion results on the catalyst are shown in Table 1 below:
[0049] Table 1
[0050]
[0051] Comparative Example 1 1Pt / Mg2Al4Si5O 18
[0052] 8.0610 g of magnesium oxide (MgO), 30.0430 g of silicon dioxide (SiO2), and 20.3930 g of aluminum oxide (Al2O3) were weighed and mixed. The mixture was calcined at 1200° C. for 3 hours and ground into powder to obtain a cordierite carrier.
[0053] Pour 0.1638g of chloroplatinic acid solution (1g of chloroplatinic acid contains 0.1233g of Pt) and deionized water into a beaker, stir for 5 minutes, and then ultrasonicate for 5 minutes. Add 2g of Mg2Al4Si5O 18, stirred for 30 minutes, and allowed to stand for 24 hours; dried at 60°C for 12 hours, and calcined in a muffle furnace at 500°C for 5 hours; the product was washed after cooling, dried at 120°C for 12 hours, and finally reduced with 5 vol% H2 / N2 at 200°C for 30 minutes to obtain a Pt catalyst with a Pt content of 1 wt.%, named 1Pt / Mg2Al4Si5O 18 Catalyst: 1Pt / Mg2Al4Si5O 18 High-resolution scanning transmission electron microscopy images of the catalysts are shown in Figure 2. Figure 1 (b) As shown in this example, 1Pt / Mg2Al4Si5O 18 The dispersion of Pt in the catalyst is 14%, which is measured by hydrogen pulse adsorption at 50°C using a Micromeritics AutoChem II 2920 instrument. 18 The weight percentage of Pt in the catalyst is 1 wt.%, which is obtained by detecting with an Agilent 5110 inductively coupled plasma spectrometer.
[0054] 1Pt / Mg2Al4Si5O 18 The performance evaluation of the catalyst was carried out in a fixed bed reactor. 0.1 g of catalyst was weighed and loaded into the fixed bed reactor. The 1Pt / Mg2Al4Si5O 18 The activity of the catalyst at different temperatures under the conditions of normal pressure, relative humidity of 25%, formaldehyde concentration of 150 ppm, and space velocity of 30,000 mL / (gh).
[0055] 1Pt / Mg2Al4Si5O 18 The HCHO conversion results of the catalyst are as follows Figure 2 As shown, the stability Figure 3 shown.
[0056] Comparative Example 2 9NiO-1Pt / Al2O3
[0057] 0.1638g of chloroplatinic acid solution (1g of chloroplatinic acid contains 0.1233g of Pt), 0.9817g of nickel nitrate hexahydrate, and deionized water were poured into a beaker, stirred for 5 minutes, and then ultrasonicated for 5 minutes. 2g of Al2O3 (Shandong Aluminum Company) was added to the solution, stirred for 30 minutes, and allowed to stand for 24 hours. The solution was then dried at 60°C for 12 hours and calcined in a muffle furnace at 500°C for 5 hours. The cooled product was washed, dried at 120°C for 12 hours, and finally reduced with 5vol% H2 / N2 at 200°C for 30 minutes to obtain a Pt catalyst with a nickel content of 9wt.% and a Pt content of 1wt.%, designated as 9NiO-1Pt / Al2O3 catalyst. The 9NiO-1Pt / Al2O3 catalyst prepared in this example had a Pt content of 1wt.% and a Ni content of 9wt.%. The data were obtained using an Agilent 5110 inductively coupled plasma spectrometer.
[0058] The performance evaluation of the 9NiO-1Pt / Al2O3 catalyst was carried out in a fixed-bed reactor. 0.1 g of the catalyst was weighed and loaded into the fixed-bed reactor. The activity of the 9NiO-1Pt / Al2O3 catalyst was tested at different temperatures under normal pressure and a space velocity of 30,000 mL / (gh). The HCHO conversion results on the 9NiO-1Pt / Al2O3 catalyst at different temperatures are shown in Table 2 below:
[0059] Table 2
[0060]
[0061] In summary, the performance evaluation comparison of the corresponding catalysts in Examples 1 and 2, 3 and 4 with those in Comparative Examples 1 and 2 in the HCHO oxidation reaction shows that the highly dispersed small-sized 9NiO-1Pt / Mg2Al4Si5O prepared by the method of the present invention is 18 The activity and stability in formaldehyde oxidation reaction are the best, and are much higher than 1Pt / Mg2Al4Si5O 18 and 9NiO-1Pt / Al2O3 catalyst.
[0062] Based on the above examples, the present invention discloses that using NiO as an additive can significantly improve the dispersion of Pt on the cordierite support and greatly reduce the size of Pt nanoparticles, thereby significantly improving the low-temperature activity and long-term stability of the cordierite-supported Pt catalyst in the formaldehyde oxidation reaction. It is known to those skilled in the art that the general structural formula of the cordierite support is Mg 2-a X a Al4Si5O 18For example, X can be replaced by one or more of Fe, Mn and Ni, or other metal or non-metal elements commonly used in the art.
Claims
1. A supported Pt-based catalyst, characterized in that The invention comprises Pt, NiO and a cordierite carrier, wherein the Pt and NiO are loaded on the cordierite carrier.
2. A supported Pt-based catalyst according to claim 1, characterized in that The cordierite carrier structure is generally Mg 2-a X a Al4Si5O 18 , X is one or more of Fe, Mn and Ni, wherein 0≤a≤1, and when a is 0, the general structure formula of the cordierite support is Mg2Al4Si5O 18 .
3. A highly dispersed small-sized supported Pt-based catalyst according to claim 1, characterized in that: The mass ratio of Ni to Pt is 9:
1.
4. A purification device provided with the supported Pt-based catalyst according to claims 1 to 3.
5. A purification device provided with a supported Pt-based catalyst according to claim 4, characterized in that: Purification equipment is used to purify formaldehyde.
6. A method for preparing a supported Pt-based catalyst, characterized in that: The following steps are involved: Step 1: MgO, SiO2, Al2O3 and one or more metal oxides of Fe, Mn and Ni are mixed, ground and calcined to obtain a cordierite support; Step 2: Immerse the cordierite support in a mixed solution of Pt precursor and Ni salt, stir, stand for aging, dry and then calcine, and then wash, dry and reduce to obtain a highly dispersed small-sized Pt-based catalyst.
7. The method for preparing a supported Pt-based catalyst according to claim 6, wherein: The Pt precursor is one or more of chloride, nitrate, acetate, or acetylacetonate; and the Ni salt is one or more of chloride, nitrate, acetate, or sulfate.
8. Use of the supported Pt-based catalyst according to claims 1 to 3 in the catalytic oxidation reaction of HCHO.
9. The use according to claim 8, characterized in that In the HCHO catalytic oxidation reaction, the concentration of HCHO is 0-500 ppm (excluding 0).
10. The use according to claim 8, characterized in that In the HCHO catalytic oxidation reaction, the space velocity is 0-100000 mL / (gh) and does not include 0.