A carbon monoxide refining catalyst and its preparation method

Abstract

This invention discloses a carbon monoxide refining catalyst and its preparation method. The catalyst comprises an alumina support, an active component palladium (Pd), and an auxiliary metal M. The active component palladium (Pd) is dispersed in single-atom form on the surface of the auxiliary metal M to form PdM single-atom alloy particles supported on the alumina support. Based on the mass of the alumina support in the catalyst, the content of the active component palladium (Pd) is 0.01% to 0.5% of the weight of the support, and the content of the auxiliary metal M is 0.05% to 10% of the weight of the support. The auxiliary metal M is selected from any one of silver, copper, molybdenum, zinc, tin, or indium. This invention, by synthesizing palladium single-atom alloys and then dispersing these single-atom alloys on an inert alumina support to prepare a carbon monoxide refining catalyst, effectively solves the problem of excessive carbon monoxide consumption when removing hydrogen from carbon monoxide and producing high-purity carbon monoxide using oxygen oxidation.

Description

Technical Field

[0001] This invention relates to a carbon monoxide refining catalyst and its preparation method, belonging to the field of catalyst technology. Background Technology

[0002] Carbon monoxide (CO) is an important chemical raw material, used to synthesize various high-value-added chemical products such as acetic acid, dimethyl oxalate, ethylene glycol, and isocyanates. Carbon monoxide (CO) resources are abundant, widely found in syngas, water gas, and semi-water gas from petroleum and coal conversions, but it often coexists with impurities such as N2, H2, CH4, and CO2. High-purity (>99.999%) CO is crucial for ensuring the quality of chemical products; the presence of hydrogen significantly affects the quality of dimethyl oxalate. Therefore, obtaining high-purity carbon monoxide efficiently and economically is of great significance to the chemical industry.

[0003] Currently, the main methods for purifying carbon monoxide are pressure swing adsorption (PSA) and cryogenic separation. PSA can separate carbon monoxide, but its effect on hydrogen removal is limited [Ma, XZ et al. Chem. Soc. Rev. 52, 3741-3777(2023).]; cryogenic separation can deeply purify carbon monoxide, but requires energy-intensive cryogenic equipment [Bassett, JD et al. 5,832,747 (1998).]. In recent years, oxygen oxidation has been considered a potential technology for the efficient production of high-purity carbon monoxide. However, because the catalytic oxidation thermodynamic properties of carbon monoxide and hydrogen are similar (CO + O2 → CO2, ΔH = −283 kJ / mol; H2 + O2 → H2O(l), ΔH = −286 kJ / mol), their enthalpy changes differ by only 3 kJ / mol, it is difficult to avoid oxidizing carbon monoxide when oxidizing hydrogen. Existing catalysts for oxygen oxidation, such as the bimetallic oxidation catalyst prepared by patent CN105618042A, use rare earth elements as promoters, resulting in high catalyst costs. Although the active crystal facet defect type palladium chloride catalyst (CU-PdClx / Al2O3) prepared by Luyang Qiao et al. has a high hydrogen conversion rate, the preparation steps of this catalyst are complex and the CO loss rate is high [Qiao, L. et al. ChemCatChem 8, 1909-1914 (2016).].

[0004] In summary, existing technologies for carbon monoxide purification either suffer from poor separation efficiency or high energy consumption during the separation process. Furthermore, catalysts used for carbon monoxide purification are costly, complex to prepare, and have high carbon monoxide loss rates. These factors significantly limit the development and application of carbon monoxide purification catalysts. Therefore, developing a low-cost, low-loss carbon monoxide purification catalyst is of significant economic and industrial production importance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a carbon monoxide refining catalyst and its preparation method, primarily solving the problem of excessive carbon monoxide consumption during the removal of hydrogen from carbon monoxide and the production of high-purity carbon monoxide via oxygen oxidation. This invention effectively solves the aforementioned problem by synthesizing a palladium single-atom alloy and then dispersing this single-atom alloy onto an inert alumina support to prepare the carbon monoxide refining catalyst. This refining catalyst exhibits almost no oxidation of carbon monoxide during the catalytic oxidation of hydrogen, has a low content of precious metals, and utilizes an inexpensive inert alumina support, making it ideal for the industrial production of carbon monoxide refining catalysts.

[0006] The technical solution provided by this invention is as follows:

[0007] This invention provides a carbon monoxide refining catalyst, comprising an alumina support, palladium Pd as an active component, and an auxiliary metal M. The active component palladium Pd is dispersed in single-atom form on the surface of the auxiliary metal M to form PdM single-atom alloy particles supported on the alumina support. Based on the mass of the alumina support in the catalyst, the content of the active component palladium Pd is 0.01% to 0.5% of the weight of the support, and the content of the auxiliary metal M is 0.05% to 10% of the weight of the support. The auxiliary metal M is selected from any one of silver, copper, molybdenum, zinc, tin, or indium.

[0008] Furthermore, the supported alumina is a mixed crystal form of ε-Al2O3 and θ-Al2O3, and the content of ε-Al2O3 is 60% to 80% of the weight of the supported alumina in the catalyst.

[0009] Furthermore, the auxiliary metal M is silver, and based on the mass of the alumina support in the catalyst, the content of the active ingredient palladium Pd is 0.3% to 0.5% of the support weight, and the content of silver is 0.3% to 0.5% of the support weight.

[0010] Furthermore, based on the mass of the alumina support in the catalyst, the content of the active ingredient palladium Pd is 0.3% of the support weight, and the content of silver is 0.5% of the support weight.

[0011] Furthermore, the particle size of the palladium-silver single-atom alloy particles ranges from 4 to 6 nm.

[0012] The present invention also provides a method for preparing the above-described carbon monoxide refining catalyst, characterized in that the method includes the following steps:

[0013] A solution of soluble palladium salt and auxiliary metal salt is mixed to prepare an impregnation solution;

[0014] Starting alumina γ-Al2O3 is calcined at 600℃~1000℃ for 4~8h, and then cooled to 25℃ to obtain spherical mixed crystalline supported alumina; wherein, the mixed crystalline supported alumina is ε-Al2O3 and θ-Al2O3, and the content of ε-Al2O3 is 60%~80% of the weight of the supported alumina in the catalyst;

[0015] A mixed-crystal support alumina and an impregnation solution were thoroughly mixed to obtain a PdM / Al2O3 catalyst precursor;

[0016] The carbon monoxide refining catalyst is obtained by aging and calcining the catalyst precursor in air.

[0017] Furthermore, the soluble palladium salt is selected from any one of palladium chloride, palladium nitrate, and chloropalladium acid.

[0018] Furthermore, the salt solution of the auxiliary metal is selected from any one of nitrates, sulfates, carbonates, or chlorides.

[0019] Furthermore, the volume range of the spherical mixed-crystal carrier alumina is 0.1 mm. 3 ~10cm 3 .

[0020] Furthermore, the aging time is 1 to 8 hours; the calcination temperature is 350°C to 900°C, and the calcination time is 4 to 72 hours.

[0021] Beneficial effects

[0022] Studies have shown that various forms of Pd can effectively dissociate H2, forming H2O under the action of O2. When Pd reacts with CO, two CO adsorption modes occur: linear adsorption and bridged adsorption. CO needs to be adsorbed on the {111} crystal facet of Pd in ​​a bridged manner. O2 attacks the CO at this point, and the CO is oxidized to CO2. The {111} crystal facet of Pd is the active site for CO catalysis [Xu, ZN]. et al . ACS Catal. 3, 118-122 (2013). If CO is adsorbed onto Pd in ​​a linear manner, desorption will occur before oxidation, and CO will not be oxidized.

[0023] In this invention, by constructing a Pd single-atom alloy, the {111} crystal plane of Pd that can activate CO is greatly destroyed, leaving only Pd single atoms that can effectively activate H2. This effectively solves the problem of CO being oxidized during the catalytic oxidation of H2, significantly reducing the carbon monoxide loss rate. Furthermore, this invention significantly reduces costs due to its low content of precious metals and the inexpensive price of the inert alumina support, achieving excellent technical results. Attached Figure Description

[0024] Figure 1 For Pd 0.3wt% Ag 0.5wt% / Al2O3、Pd 0.5wt% The X-ray diffraction (XRD) patterns of Pd / Al2O3 and PdAg / Al2O3 showed no sharp peaks, indicating that no significant aggregation occurred in Pd / Al2O3 or PdAg / Al2O3, and all palladium exhibited good dispersibility.

[0025] Figure 2 The image shows a high-resolution transmission electron microscope (HRTEM) image of the PdAg / Al2O3 catalyst. The results show that the particle size of the PdAg alloy particles ranges from 4 to 6 nanometers, and isolated palladium atoms are dispersed on the alloy surface as bright spots to form single atoms.

[0026] Figure 3 a and Figure 3 b shows the X-ray photoelectron spectroscopy (XPS) spectra of Pd / 3d and Ag / 3d. The results show that the 3d peaks of Pd and Ag in PdAg / Al2O3 are located at 334.6 eV and 367.4 eV, respectively, which are lower than the binding energies of Pd and Ag elements at 335.2 eV and 368.3 eV, respectively, confirming the formation of PdAg alloy.

[0027] Figure 4 A comparison of the CO infrared spectra (CO-IR) of PdAg / Al2O3 and Pd / Al2O3 shows that CO is mainly adsorbed via a bridged adsorption process on the Pd / Al2O3 catalyst alone, with a characteristic peak corresponding to 1970 cm⁻¹. -1 On the PdAg catalyst, CO is mainly adsorbed linearly, with a characteristic peak corresponding to 2023 cm⁻¹. -1 . Detailed Implementation

[0028] The present invention will be further described below with reference to the embodiments.

[0029] This invention provides a carbon monoxide refining catalyst, comprising an alumina support, palladium (Pd) as an active component, and an auxiliary metal M. The active component palladium is dispersed in single-atom form on the surface of the auxiliary metal M to form PdM single-atom alloy particles supported on the alumina support. Based on the mass of the alumina support in the catalyst, the content of the active component palladium (Pd) is 0.01% to 0.5% of the weight of the support, and the content of the auxiliary metal M is 0.05% to 10% of the weight of the support. The auxiliary metal M is selected from any one of silver, copper, molybdenum, zinc, tin, or indium.

[0030] In this embodiment, the alumina support is a mixed crystal form of ε-Al2O3 and θ-Al2O3. Based on the mass of the alumina support in the catalyst, the content of ε-Al2O3 is 60% to 80% of the weight of the support.

[0031] In this embodiment, the auxiliary metal M is silver. Based on the mass of the alumina support in the catalyst, the content of the active ingredient palladium Pd is 0.3% to 0.5% of the support weight, and the content of silver is 0.3% to 0.5% of the support weight.

[0032] In this embodiment, based on the mass of alumina in the catalyst support, the content of the active ingredient palladium Pd is 0.3% of the support weight, and the content of silver is 0.5% of the support weight.

[0033] In this embodiment, the particle size of the palladium-silver single-atom alloy particles ranges from 4 to 6 nm.

[0034] The present invention also provides a method for preparing the above-described carbon monoxide refining catalyst, characterized in that the method includes the following steps:

[0035] A solution of soluble palladium salt and auxiliary metal salt is mixed to prepare an impregnation solution;

[0036] Starting alumina γ-Al2O3 is calcined at 600℃~1000℃ for 4~8h, and then cooled to 25℃ to obtain spherical mixed crystalline supported alumina; wherein, the mixed crystalline supported alumina is ε-Al2O3 and θ-Al2O3, and the content of ε-Al2O3 is 60%~80% of the weight of the supported alumina in the catalyst;

[0037] A mixed-crystal support alumina and an impregnation solution were thoroughly mixed to obtain a PdM / Al2O3 catalyst precursor;

[0038] The carbon monoxide refining catalyst is obtained by aging and calcining the catalyst precursor in air.

[0039] In this embodiment, the soluble palladium salt is selected from any one of palladium chloride, palladium nitrate, and chloropalladium acid, with palladium nitrate being preferred.

[0040] In this embodiment, the salt solution of the auxiliary metal is selected from any one of nitrates, sulfates, carbonates or chlorides, with nitrates being preferred.

[0041] In this embodiment, the volume range of the spherical mixed-crystal carrier alumina is 0.1 mm. 3 ~10cm 3 .

[0042] In this embodiment, the aging time is 1-8 hours; the calcination temperature is 350℃-900℃, preferably 450℃. o C, the roasting time is 4~72h, preferably 12h.

[0043] Example 1

[0044] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.3wt% Ag 0.5wt% The catalyst preparation process for Pd-Ag / Al2O3 catalyst is as follows: Pd(NO3)2 and AgNO3 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained. This ε-Al2O3 is then thoroughly mixed with the impregnating solution to obtain Pd-Ag / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Ag / Al2O3 catalyst. 0.3wt% Ag 0.5wt% Al2O3 carbon monoxide refining catalyst.

[0045] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.3wt% Ag 0.5wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0046] Example 2

[0047] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.5wt% Ag 0.05wt% The catalyst preparation steps for Pd-Ag / Al2O3 content are as follows: Pd(NO3)2 and AgNO3 are selected and impregnated at 25℃ according to the loading. 100g of γ-Al2O3 is calcined at 900℃ for 6h. After cooling to 25℃, spherical ε-Al2O3 (containing part of θ-Al2O3) is obtained. The ε-Al2O3 is thoroughly mixed with the impregnating solution to obtain Pd-Ag / Al2O3 catalyst precursor III. After aging III in air for 4h, it is calcined at 450℃ to obtain Pd0.3wt%Ag0.5wt% / Al2O3 carbon monoxide refined catalyst.

[0048] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.5wt% Ag 0.05wt%Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0049] Example 3

[0050] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.5wt% Ag 0.3wt% The catalyst preparation process for Pd-Ag / Al2O3 catalyst is as follows: Pd(NO3)2 and AgNO3 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained. This ε-Al2O3 is then thoroughly mixed with the impregnating solution to obtain Pd-Ag / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Ag / Al2O3 catalyst. 0.3wt% Ag 0.5wt% Al2O3 carbon monoxide refining catalyst.

[0051] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.5wt% Ag 0.3wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0052] Example 4

[0053] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.5wt% Ag 0.5wt% The catalyst preparation process for Pd-Ag / Al2O3 catalyst is as follows: Pd(NO3)2 and AgNO3 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained. This ε-Al2O3 is then thoroughly mixed with the impregnating solution to obtain Pd-Ag / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Ag / Al2O3 catalyst. 0.5wt% Ag 0.5wt% Al2O3 carbon monoxide refining catalyst.

[0054] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.5wt% Ag 0.5wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0055] Example 5

[0056] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.5wt% Ag 1.0wt% The catalyst preparation process for Pd-Ag / Al2O3 catalyst is as follows: Pd(NO3)2 and AgNO3 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained. This ε-Al2O3 is then thoroughly mixed with the impregnating solution to obtain Pd-Ag / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Ag / Al2O3 catalyst. 0.5wt% Ag 1.0wt% Al2O3 carbon monoxide refining catalyst.

[0057] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.5wt% Ag 1.0wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0058] Example 6

[0059] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.01wt% Ag 10wt% The catalyst preparation process for Pd-Ag / Al2O3 catalyst is as follows: Pd(NO3)2 and AgNO3 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained. This ε-Al2O3 is then thoroughly mixed with the impregnating solution to obtain Pd-Ag / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Ag / Al2O3 catalyst. 0.01wt% Ag10wt% Al2O3 carbon monoxide refining catalyst.

[0060] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.01wt% Ag 10wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0061] Example 7

[0062] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.3wt% Cu 0.5wt% The catalyst preparation process for Pd-Cu / Al2O3 catalyst is as follows: Pd(NO3)2 and Cu(NO3)2 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained and thoroughly mixed with the impregnating solution to obtain Pd-Cu / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Cu / Al2O3 catalyst precursor III. 0.3wt% Cu 0.5wt% Al2O3 carbon monoxide refining catalyst.

[0063] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.3wt% Cu 0.5wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0064] Example 8

[0065] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.5wt% Cu 0.05wt%The catalyst preparation process for Pd-Cu / Al2O3 catalyst is as follows: Pd(NO3)2 and Cu(NO3)2 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained and thoroughly mixed with the impregnating solution to obtain Pd-Cu / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Cu / Al2O3 catalyst precursor III. 0.5wt% Cu 0.05wt% Al2O3 carbon monoxide refining catalyst.

[0066] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.5wt% Cu 0.05wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0067] Example 9

[0068] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.5wt% Cu 0.3wt% The catalyst preparation process for Pd-Cu / Al2O3 catalyst is as follows: Pd(NO3)2 and Cu(NO3)2 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained and thoroughly mixed with the impregnating solution to obtain Pd-Cu / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Cu / Al2O3 catalyst precursor III. 0.5wt% Cu 0.3wt% Al2O3 carbon monoxide refining catalyst.

[0069] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.5wt% Cu 0.3wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0070] Example 10

[0071] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.5wt% Cu 0.5wt% The catalyst preparation process for Pd-Cu / Al2O3 catalyst is as follows: Pd(NO3)2 and Cu(NO3)2 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained and thoroughly mixed with the impregnating solution to obtain Pd-Cu / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Cu / Al2O3 catalyst precursor III. 0.5wt% Cu 0.5wt% Al2O3 carbon monoxide refining catalyst.

[0072] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.5% Cu 0.5% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0073] Example 11

[0074] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.5wt% Cu 1.0wt% The catalyst preparation process for Pd-Cu / Al2O3 catalyst is as follows: Pd(NO3)2 and Cu(NO3)2 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained and thoroughly mixed with the impregnating solution to obtain Pd-Cu / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Cu / Al2O3 catalyst precursor III. 0.5wt% Cu 1.0wt% Al2O3 carbon monoxide refining catalyst.

[0075] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.5wt% Cu 1.0wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0076] Example 12

[0077] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.01wt% Cu 10wt% The catalyst preparation process for Pd-Cu / Al2O3 catalyst is as follows: Pd(NO3)2 and Cu(NO3)2 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained and thoroughly mixed with the impregnating solution to obtain Pd-Cu / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Cu / Al2O3 catalyst precursor III. 0.01wt% Cu 10wt% Al2O3 carbon monoxide refining catalyst.

[0078] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.01wt% Cu 10wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0079] Example 13

[0080] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.3wt% Mo 0.5wt% The catalyst preparation process for Pd-Mo / Al2O3 catalyst is as follows: Pd(NO3)2 and Mo(NO3)4 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained and thoroughly mixed with the impregnating solution to obtain Pd-Mo / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Mo / Al2O3 catalyst precursor III. 0.3wt% Mo 0.5wt% Al2O3 carbon monoxide refining catalyst.

[0081] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.3wt% Mo 0.5wt%Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0082] Example 14

[0083] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.5wt% Mo 0.05wt% The catalyst preparation process for Pd-Mo / Al2O3 catalyst is as follows: Pd(NO3)2 and Mo(NO3)4 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained and thoroughly mixed with the impregnating solution to obtain Pd-Mo / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Mo / Al2O3 catalyst precursor III. 0.3wt% Mo 0.05wt% Al2O3 carbon monoxide refining catalyst.

[0084] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.5wt% Mo 0.05wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0085] Example 15

[0086] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.5wt% Mo 0.3wt% The catalyst preparation process for Pd-Mo / Al2O3 catalyst is as follows: Pd(NO3)2 and Mo(NO3)4 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained and thoroughly mixed with the impregnating solution to obtain Pd-Mo / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Mo / Al2O3 catalyst precursor III. 0.3wt% Mo 0.3wt% Al2O3 carbon monoxide refining catalyst.

[0087] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.5wt% Mo 0.3wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0088] Example 16

[0089] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.5wt% Mo 0.5wt% The catalyst preparation process for Pd-Mo / Al2O3 catalyst is as follows: Pd(NO3)2 and Mo(NO3)4 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained and thoroughly mixed with the impregnating solution to obtain Pd-Mo / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Mo / Al2O3 catalyst precursor III. 0.3wt% Mo 0.5wt% Al2O3 carbon monoxide refining catalyst.

[0090] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.5wt% Mo 0.5wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0091] Example 17

[0092] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.5wt% Mo 1.0wt% The catalyst preparation process for Pd-Mo / Al2O3 catalyst is as follows: Pd(NO3)2 and Mo(NO3)4 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained and thoroughly mixed with the impregnating solution to obtain Pd-Mo / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Mo / Al2O3 catalyst precursor III. 0.5wt% Mo1.0wt% Al2O3 carbon monoxide refining catalyst.

[0093] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.5wt% Mo 1.0wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0094] Example 18

[0095] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.01wt% Mo 10wt% The catalyst preparation process for Pd-Mo / Al2O3 catalyst is as follows: Pd(NO3)2 and Mo(NO3)4 are selected and impregnated at 25°C according to their loading amounts. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained and thoroughly mixed with the impregnating solution to obtain Pd-Mo / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd-Mo / Al2O3 catalyst precursor III. 0.01wt% Mo 10wt% Al2O3 carbon monoxide refining catalyst.

[0096] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.01wt% Mo 10wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0097] Comparative Example 1

[0098] According to the literature [Qiao, L]. et al . ChemCatChem[8, 1909-1914 (2016).] Method: 0.089 g of palladium chloride was dissolved in 10 ml of deionized water to prepare a solution with a concentration of 0.05 mol / L. The pH of the solution was adjusted to 1 using 1 mol / L hydrochloric acid to obtain solution A. 5.3 g of γ-Al₂O₃ with a diameter of 0.3-0.5 mm was weighed and impregnated in the prepared solution for 4 h. After complete impregnation, the residual liquid was filtered off to obtain catalyst precursor B. Precursor B was calcined under vacuum at 400 °C for 4 h, followed by microwave treatment at 3 kW power for 0.1 h to obtain catalyst precursor C. Catalyst precursor C was treated at 150 °C for 1 h in a mixed atmosphere of H₂O / H₂ / Ar (H₂O content 0.5%, H₂ content 10%) to prepare the CU-PdClx / Al₂O₃ catalyst.

[0099] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5 g CU-PdClx / Al2O3 catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O2, with a feed gas molar ratio of CO:H2 = 99.5%:0.1% and an H2:O2 molar ratio of 1:4; gas space velocity: 4000 h⁻¹. -1 .

[0100] Comparative Example 2

[0101] According to the method in patent CN105618042A, 10g of alumina support was weighed and calcined in a muffle furnace at 300℃ to obtain activated alumina support. 10ml of a 0.08mol / L lanthanum nitrate solution was added dropwise to the 10g activated alumina support, and after impregnation at room temperature for 6h, it was dried in an oven at 120℃ for 15h, then calcined in a muffle furnace at 450℃ for 5h, and cooled to room temperature to obtain a La-doped catalyst precursor. 10ml of a 0.10mol / L palladium nitrate solution was added dropwise to the 10g catalyst precursor, and after impregnation at room temperature for 6h, it was dried in an oven at 120℃ for 15h, and then calcined at 300℃ for 3h to obtain the PdO / LaOx-Al2O3 catalyst.

[0102] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g PdO / LaO x - Al2O3 catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200℃; introduced gases: feed gas and O2, wherein the volume ratio of feed gas CO:H2 = 99.5%:0.1%, and the molar ratio of H2 to O2 is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0103] Comparative Example 3

[0104] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.5wt% The catalyst preparation process for Pd / Al2O3 content is as follows: Pd(NO3)2 is used to prepare an impregnation solution at 25°C according to the loading amount. 100g of γ-Al2O3 is calcined at 900°C for 6 hours. After cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained. This ε-Al2O3 is then thoroughly mixed with the impregnation solution to obtain Pd / Al2O3 catalyst precursor III. Precursor III is aged in air for 4 hours and then calcined at 450°C to obtain Pd / Al2O3 catalyst. 0.5wt% Al2O3 carbon monoxide refining catalyst.

[0105] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.5% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0106] Comparative Example 4

[0107] Weigh 100g of alumina support (γ-Al2O3), and calculate it as elemental metal (hereinafter the same), according to Pd 0.3wt% Fe 0.5wt% The catalyst preparation process for Pd-Cu / Al2O3 content is as follows: Pd(NO3)2 and Fe(NO3) are selected and impregnated at 25°C according to the loading amount. 100g of γ-Al2O3 is calcined at 900°C for 6h, and after cooling to 25°C, spherical ε-Al2O3 (containing some θ-Al2O3) is obtained. This ε-Al2O3 is then thoroughly mixed with the impregnating solution to obtain Pd-Cu / Al2O3 catalyst precursor III. Precursor III is aged in air for 4h and then calcined at 450°C to obtain Pd-Cu / Al2O3 catalyst precursor III. 0.3wt% Fe 0.5wt% Al2O3 carbon monoxide refining catalyst.

[0108] Catalytic evaluation was conducted using a fixed-bed reactor. Specific conditions were as follows: 5g Pd 0.3wt% Fe 0.5wt% Al₂O₃ catalyst; reaction pressure: 0.3 MPa; reaction temperature: 200 °C; introduced gases: feed gas and O₂, wherein the molar ratio of feed gas CO:H₂ = 99.5%:0.1%, and the molar ratio of H₂ to O₂ is 1:4; gas space velocity: 4000 h⁻¹ -1 .

[0109] The results of specific embodiments and comparative examples are shown in Table 1 below.

[0110] Table 1

[0111] serial number catalyst <![CDATA[Residual amount of H2 (ppm)]]> CO loss rate (%) Whether an alloy is formed Example 1 <![CDATA[Pd 0.3wt% Ag 0.5wt% Al2O3 2 0.17 yes Example 2 <![CDATA[Pd 0.5wt% Ag 0.05wt% Al2O3 20 0.33 yes Example 3 <![CDATA[Pd 0.5wt% Ag 0.3wt% Al2O3 3 0.21 yes Example 4 <![CDATA[Pd 0.5wt% Ag 0.5wt% Al2O3 8 0.31 yes Example 5 <![CDATA[Pd 0.5wt% Ag 1.0wt% Al2O3 6 0.66 yes Example 6 <![CDATA[Pd 0.01wt% Ag 10wt% Al2O3 32 0.68 yes Example 7 <![CDATA[Pd 0.3% With 0.5% / Al2O3]]> 80 0.23 yes Example 8 <![CDATA[Pd 0.5wt% With 0.05wt% / Al2O3]]> 58 0.43 yes Example 9 <![CDATA[Pd 0.5wt% With 0.3wt% / Al2O3]]> 73 0.34 yes Example 10 <![CDATA[Pd 0.5wt% With 0.5wt% / Al2O3]]> 68 0.42 yes Example 11 <![CDATA[Pd 0.5wt% With 1.0wt% / Al2O3]]> 85 0.76 yes Example 12 <![CDATA[Pd 0.01wt% With 10% / Al2O3]]> 76 0.69 yes Example 13 <![CDATA[Pd 0.3wt% Mo 0.5wt% / Al2O3]]> 30 0.20 yes Example 14 <![CDATA[Pd 0.5wt% Mo 0.05wt% / Al2O3]]> 36 0.54 yes Example 15 <![CDATA[Pd 0.5wt% Mo 0.3wt% / Al2O3]]> 23 0.27 yes Example 16 <![CDATA[Pd 0.5wt% Mo 0.5wt% / Al2O3]]> 46 0.45 yes Example 17 <![CDATA[Pd 0.5wt% Mo 1.0wt% / Al2O3]]> 57 0.88 yes Example 18 <![CDATA[Pd 0.01wt% Mo 10wt% / Al2O3]]> 61 0.48 yes Comparative Example 1 <![CDATA[CU-PdClx / Al2O3]]> 10 1.56 no Comparative Example 2 <![CDATA[PdO / LaO x -Al2O3]]> 38 3.83 no Comparative Example 3 <![CDATA[Pd 0.5wt% Al2O3 17 0.80 no Comparative Example 4 <![CDATA[Pd 0.3wt% Fe 0.5wt% Al2O3 101 1.07 yes

[0112] As can be seen from Examples 1 to 18, the residual H2 content all meets the requirements for high-purity CO, and the CO loss rate is also less than 1%. In all examples using auxiliary metals, PdM single-atom alloy particles were successfully formed. This indicates that the present invention can effectively solve the problem of excessive carbon monoxide consumption when removing hydrogen from carbon monoxide and producing high-purity carbon monoxide using oxygen oxidation.

[0113] Although the catalyst in Comparative Example 1 has a low hydrogen residue, its preparation steps are complex and the CO loss rate is high.

[0114] The catalyst in Comparative Example 2 uses rare earth elements as promoters, resulting in high catalyst cost and a high CO loss rate.

[0115] The catalyst in Comparative Example 3 contained only Pd and no auxiliary metal was added, resulting in poor catalytic performance. This indicates that the addition of auxiliary metal is necessary to improve catalytic performance.

[0116] Although the catalyst in Comparative Example 4 formed an alloy, the unsuitable auxiliary metal Fe was selected, resulting in extremely high H2 residue and poor catalytic performance.

[0117] The catalyst in Example 1 significantly disrupts the {111} crystal plane of Pd that activates CO, retaining only the Pd single atoms that can effectively activate H2. This allows CO to be adsorbed onto Pd in ​​a linear fashion, with desorption preceding oxidation, preventing CO from being oxidized and achieving extremely low H2 residue and CO loss rates. Compared to other examples and comparative examples, Example 1 demonstrates a better balance in terms of catalytic performance, cost-effectiveness, and preparation feasibility.

[0118] The above description is merely a preferred embodiment of the present invention and is not intended to limit the implementation. It should be noted that those skilled in the art can make improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A carbon monoxide refining catalyst, characterized in that, The catalyst comprises an alumina support, an active component palladium (Pd), and an auxiliary metal M. The active component palladium (Pd) is dispersed in single-atom form on the surface of the auxiliary metal M to form PdM single-atom alloy particles supported on the alumina support. Based on the mass of the alumina support in the catalyst, the content of the active component palladium (Pd) is 0.01% to 0.5% of the weight of the support, and the content of the auxiliary metal M is 0.05% to 10% of the weight of the support. The auxiliary metal M is selected from any one of silver, copper, and molybdenum. The alumina support is a mixed crystal form of ε-Al₂O₃ and θ-Al₂O₃. Based on the mass of the alumina support in the catalyst, the content of ε-Al₂O₃ is 60% to 80% of the weight of the support.

2. The carbon monoxide refining catalyst according to claim 1, characterized in that, The auxiliary metal M is silver. Based on the mass of alumina in the catalyst support, the content of the active ingredient palladium Pd is 0.3% to 0.5% of the support weight, and the content of silver is 0.3% to 0.5% of the support weight.

3. The carbon monoxide refining catalyst according to claim 2, characterized in that, Based on the mass of alumina in the catalyst support, the content of palladium Pd, the active ingredient, is 0.3% of the support weight, and the content of silver is 0.5% of the support weight.

4. The carbon monoxide refining catalyst according to claim 3, characterized in that, The particle size range of palladium-silver (PdAg) single-atom alloy particles is between 4 and 6 nm.

5. A method for preparing a carbon monoxide refining catalyst according to any one of claims 1-4, characterized in that, The method includes the following steps: A solution of soluble palladium salt and auxiliary metal salt is mixed to prepare an impregnation solution; Starting alumina γ-Al2O3 is calcined at 600℃~1000℃ for 4~8h, and then cooled to 25℃ to obtain spherical mixed crystalline supported alumina; wherein, the mixed crystalline supported alumina is ε-Al2O3 and θ-Al2O3, and the content of ε-Al2O3 is 60%~80% of the weight of the supported alumina in the catalyst; A mixed-crystal support alumina and an impregnation solution were thoroughly mixed to obtain a PdM / Al2O3 catalyst precursor; The carbon monoxide refining catalyst is obtained by aging and calcining the catalyst precursor in air.

6. The preparation method according to claim 5, characterized in that, The soluble palladium salt is selected from any one of palladium chloride, palladium nitrate, and chloropalladium acid.

7. The preparation method according to claim 5, characterized in that, The salt solution of the auxiliary metal is selected from any one of nitrates, sulfates, carbonates, or chlorides.

8. The preparation method according to claim 5, characterized in that, The volume range of the spherical mixed-crystal carrier alumina is 0.1 mm. 3 ~10cm 3 .

9. The preparation method according to claim 5, characterized in that, The aging time is 1~8h; the calcination temperature is 350℃~900℃, and the calcination time is 4~72h.

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