Carbon monoxide refining catalyst and preparation method thereof

Abstract

The invention discloses a carbon monoxide refining catalyst and a preparation method, the catalyst comprises a carrier alumina, an active component palladium Pd and an auxiliary agent metal M. The active component palladium Pd is dispersed on the surface of the auxiliary agent metal M in a monatomic form to form PdM monatomic alloy particles loaded on the carrier alumina. On the basis of the mass of the carrier aluminum oxide in the catalyst, the content of the active component palladium Pd is 0.01%-0.5% of the weight of the carrier, the content of the assistant metal M is 0.05%-10% of the weight of the carrier, and the assistant metal M is any one selected from silver, copper, molybdenum, zinc, tin or indium. According to the method for preparing the carbon monoxide refining catalyst by synthesizing the monatomic alloy of palladium and dispersing the monatomic alloy on the inert aluminum oxide carrier, the problem that the carbon monoxide is excessively consumed when hydrogen is removed from the carbon monoxide and high-purity carbon monoxide is produced by an oxygen oxidation method is well solved.

Description

Technical Field

[0001] The invention relates to a carbon monoxide refining catalyst and a preparation method thereof, belonging to the technical field of catalysts. Background Art

[0002] Carbon monoxide (CO) is an important chemical raw material, which can be used to synthesize a variety of high value-added chemical products such as acetic acid, dimethyl oxalate, ethylene glycol, isocyanate, etc. Carbon monoxide (CO) is abundant in resources and widely exists in synthesis gas, water gas, and semi-water gas converted from petroleum and coal, but it often coexists with impurities such as N2, H2, CH4, and CO2. High-purity (>99.999%) CO is crucial to ensure the quality of chemical products, and the presence of hydrogen will significantly affect the quality of dimethyl oxalate. Therefore, how to efficiently and economically obtain high-purity carbon monoxide is of great significance to the chemical industry.

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

[0004] In summary, the existing technologies for carbon monoxide purification either have poor separation effects or high energy consumption in the separation process, and the catalysts used for carbon monoxide purification are high in cost, complex in preparation, and have high carbon monoxide loss rates. These factors have greatly limited the development and application of carbon monoxide purification catalysts. Therefore, the development of a low-cost, low-loss carbon monoxide purification catalyst has important economic and industrial production significance. Summary of the invention

[0005] In view of the deficiencies of the prior art, the present invention provides a carbon monoxide refining catalyst and a preparation method, which mainly solves the problem of excessive consumption of carbon monoxide when removing hydrogen from carbon monoxide and producing high-purity carbon monoxide by oxygen oxidation. The present invention solves the above-mentioned problem by synthesizing a single-atom alloy of palladium and then dispersing the single-atom alloy on an inert alumina carrier to prepare a carbon monoxide refining catalyst. The refined catalyst hardly oxidizes carbon monoxide when catalytically oxidizing hydrogen, contains a low amount of precious metals and the inert alumina carrier is inexpensive, and can be used very well in the industrial production of carbon monoxide refining catalysts.

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

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

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

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

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

[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-mentioned carbon monoxide refining catalyst, characterized in that the method comprises the following steps: Mixing a soluble palladium salt and a salt solution of an auxiliary metal to prepare an impregnation solution; The starting alumina γ-Al2O3 is calcined at 600°C to 1000°C for 4 to 8 hours, and then cooled to 25°C to obtain a spherical mixed crystal carrier alumina; wherein the mixed crystal carrier alumina is ε-Al2O3 and θ-Al2O3, and the content of the ε-Al2O3 is 60% to 80% of the carrier weight based on the weight of the carrier alumina in the catalyst; The mixed crystal carrier alumina and the impregnation solution are fully mixed to obtain a PdM / Al2O3 catalyst precursor; The catalyst precursor is aged and calcined in air to obtain the carbon monoxide purification catalyst.

[0013] Furthermore, the soluble palladium salt is selected from any one of palladium chloride, palladium nitrate and chloropalladic acid.

[0014] Furthermore, the salt solution of the auxiliary metal is selected from any one of nitrate, sulfate, carbonate or chloride.

[0015] Furthermore, the volume range of the spherical mixed crystal carrier alumina is 0.1 mm 3 ~10cm 3 .

[0016] 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.

[0017] Beneficial Effects

[0018] Studies have shown that various forms of Pd can effectively dissociate H2 and form H2O under the action of O2; and when Pd reacts with CO, it will produce two CO adsorption modes: one is linear adsorption and the other is bridge adsorption. CO needs to be adsorbed on the {111} crystal plane of Pd in ​​a bridge manner. O2 attacks CO at this time, and CO is oxidized to CO2. The {111} crystal plane of Pd is the active site for CO catalysis [Xu, ZN et al . ACS Catal. 3, 118-122 (2013).】. If CO is adsorbed on Pd in ​​a linear manner, desorption will occur before oxidation, and CO will not be oxidized.

[0019] In the present invention, by constructing a Pd single-atom alloy, the {111} crystal plane of Pd that can activate CO is greatly destroyed, and only the Pd single atom that can effectively activate H2 is retained, which effectively solves the problem that CO is also oxidized during the catalytic oxidation of H2, and greatly reduces the carbon monoxide loss rate. In addition, the present invention greatly reduces costs and achieves excellent technical effects due to the low amount of precious metals contained and the low price of the inert alumina carrier. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Pd 0.3wt% Ag 0.5wt% / Al2O3、Pd 0.5wt% The X-ray diffraction (XRD) patterns of Pd / Al2O3 and Al2O3 showed no sharp peaks, indicating that no obvious aggregation occurred in Pd / Al2O3 or PdAg / Al2O3, and all palladium had good dispersion.

[0021] Figure 2 This is a high-resolution transmission electron microscopy (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 in the form of bright spots to form single atoms.

[0022] Figure 3 a and Figure 3 b is the X-ray photoelectron spectroscopy (XPS) spectrum 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 energy of Pd and Ag elements of 335.2 eV and 368.3 eV, confirming the formation of PdAg alloy.

[0023] Figure 4 Comparison of CO infrared spectra (CO-IR) of PdAg / Al2O3 and Pd / Al2O3. The results show that on the catalyst with only Pd / , CO is mainly adsorbed in the bridge form, with a characteristic peak corresponding to 1970 cm -1 On the catalyst with PdAg, CO is mainly adsorbed linearly, with a characteristic peak corresponding to 2023 cm -1 . DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the embodiments.

[0025] The invention provides a carbon monoxide refining catalyst. The catalyst comprises a carrier aluminum oxide, an active ingredient palladium Pd and an auxiliary metal M. The active ingredient palladium is dispersed in a single-atom form on the surface of the auxiliary metal M to form PdM single-atom alloy particles loaded on the carrier aluminum oxide. Based on the mass of the carrier aluminum oxide in the catalyst, the content of the active ingredient palladium Pd is 0.01% to 0.5% of the weight of the carrier, the content of the auxiliary metal M is 0.05% to 10% of the weight of the carrier, and the auxiliary metal M is selected from any one of silver, copper, molybdenum, zinc, tin or indium.

[0026] In this embodiment, the carrier alumina is a mixed crystal of ε-Al2O3 and θ-Al2O3. Based on the mass of the carrier alumina in the catalyst, the content of ε-Al2O3 is 60% to 80% of the carrier weight.

[0027] In this embodiment, the auxiliary metal M is silver. Based on the mass of the carrier alumina in the catalyst, the content of the active ingredient palladium Pd is 0.3% to 0.5% of the weight of the carrier, and the content of silver is 0.3% to 0.5% of the weight of the carrier.

[0028] In this embodiment, based on the mass of the carrier alumina in the catalyst, the content of the active ingredient palladium Pd is 0.3% of the weight of the carrier, and the content of silver is 0.5% of the weight of the carrier.

[0029] In this embodiment, the particle size of the palladium-silver single-atom alloy particles ranges from 4 to 6 nm.

[0030] The present invention also provides a method for preparing the above-mentioned carbon monoxide refining catalyst, characterized in that the method comprises the following steps: Mixing a soluble palladium salt and a salt solution of an auxiliary metal to prepare an impregnation solution; The starting alumina γ-Al2O3 is calcined at 600°C to 1000°C for 4 to 8 hours, and then cooled to 25°C to obtain a spherical mixed crystal carrier alumina; wherein the mixed crystal carrier alumina is ε-Al2O3 and θ-Al2O3, and the content of the ε-Al2O3 is 60% to 80% of the carrier weight based on the weight of the carrier alumina in the catalyst; The mixed crystal carrier alumina and the impregnation solution are fully mixed to obtain a PdM / Al2O3 catalyst precursor; The catalyst precursor is aged and calcined in air to obtain the carbon monoxide purification catalyst.

[0031] In this embodiment, the soluble palladium salt is selected from any one of palladium chloride, palladium nitrate, and chloropalladic acid, preferably palladium nitrate.

[0032] In this embodiment, the salt solution of the auxiliary metal is selected from any one of nitrate, sulfate, carbonate or chloride, preferably nitrate.

[0033] In this embodiment, the volume range of the spherical mixed crystal carrier alumina is 0.1mm 3 ~10cm 3 .

[0034] In this embodiment, the aging time is 1 to 8 hours; the calcination temperature is 350°C to 900°C, preferably 450°C. oC, the calcination time is 4 to 72 hours, preferably 12 hours.

[0035] Example 1

[0036] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.3wt% Ag 0.5wt% / Al2O3 content to prepare the catalyst, the specific steps are as follows: Pd(NO3)2, AgNO3 according to the loading amount at 25 ° C to prepare the impregnation solution, at 900 ° C conditions, calcined 100g γ-Al2O3 for 6h, cooled to 25 ° C to obtain spherical ε-Al2O3 (including part of θ-Al2O3) and the impregnation solution to obtain Pd-Ag / Al2O3 catalyst precursor III; after aging III in air for 4h, calcined at 450 ° C to obtain Pd 0.3wt% Ag 0.5wt% / Al2O3 carbon monoxide refining catalyst.

[0037] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.3wt% Ag 0.5wt% / Al2O3 catalyst; reaction pressure of 0.3MPa; reaction temperature of 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity of 4000h -1 .

[0038] Example 2

[0039] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.5wt% Ag 0.05wt% / Al2O3 content to prepare the catalyst, the specific steps are as follows: Pd(NO3)2, AgNO3 according to the loading amount of the preparation of the impregnation solution at 25 ℃, calcined 100g γ-Al2O3 at 900 ℃ for 6h, cooled to 25 ℃ to obtain spherical ε-Al2O3 (including part of θ-Al2O3) and the impregnation solution to obtain Pd-Ag / Al2O3 catalyst precursor III; after aging III in air for 4h, calcined at 450 ℃ to obtain Pd0.3wt%Ag0.5wt% / Al2O3 carbon monoxide refined catalyst.

[0040] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.5wt% Ag 0.05wt% / Al2O3 catalyst; reaction pressure of 0.3MPa; reaction temperature of 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity of 4000h -1 .

[0041] Example 3

[0042] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.5wt% Ag 0.3wt% / Al2O3 content to prepare the catalyst, the specific steps are as follows: Pd(NO3)2, AgNO3 according to the loading amount at 25 ° C to prepare the impregnation solution, at 900 ° C conditions, calcined 100g γ-Al2O3 for 6h, cooled to 25 ° C to obtain spherical ε-Al2O3 (including part of θ-Al2O3) and the impregnation solution to obtain Pd-Ag / Al2O3 catalyst precursor III; after aging III in air for 4h, calcined at 450 ° C to obtain Pd 0.3wt% Ag 0.5wt% / Al2O3 carbon monoxide refining catalyst.

[0043] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.5wt% Ag 0.3wt% / Al2O3 catalyst; reaction pressure of 0.3MPa; reaction temperature of 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity of 4000h -1 .

[0044] Example 4

[0045] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.5wt% Ag 0.5wt% / Al2O3 content to prepare the catalyst, the specific steps are as follows: Pd(NO3)2, AgNO3 according to the loading amount at 25 ° C to prepare the impregnation solution, at 900 ° C conditions, calcined 100g γ-Al2O3 for 6h, cooled to 25 ° C to obtain spherical ε-Al2O3 (including part of θ-Al2O3) and the impregnation solution to obtain Pd-Ag / Al2O3 catalyst precursor III; after aging III in air for 4h, calcined at 450 ° C to obtain Pd 0.5wt% Ag 0.5wt% / Al2O3 carbon monoxide refining catalyst.

[0046] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.5wt% Ag 0.5wt% / Al2O3 catalyst; reaction pressure of 0.3MPa; reaction temperature of 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity of 4000h -1 .

[0047] Example 5

[0048] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.5wt% Ag 1.0wt% / Al2O3 content to prepare the catalyst, the specific steps are as follows: Pd(NO3)2, AgNO3 according to the loading amount at 25 ° C to prepare the impregnation solution, at 900 ° C conditions, calcined 100g γ-Al2O3 for 6h, cooled to 25 ° C to obtain spherical ε-Al2O3 (including part of θ-Al2O3) and the impregnation solution to obtain Pd-Ag / Al2O3 catalyst precursor III; after aging III in air for 4h, calcined at 450 ° C to obtain Pd 0.5wt% Ag 1.0wt% / Al2O3 carbon monoxide refining catalyst.

[0049] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.5wt% Ag 1.0wt% / Al2O3 catalyst; reaction pressure of 0.3MPa; reaction temperature of 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity of 4000h -1 .

[0050] Example 6

[0051] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.01wt% Ag 10wt% / Al2O3 content to prepare the catalyst, the specific steps are as follows: Pd(NO3)2, AgNO3 according to the loading amount at 25 ° C to prepare the impregnation solution, at 900 ° C conditions, calcined 100g γ-Al2O3 for 6h, cooled to 25 ° C to obtain spherical ε-Al2O3 (including part of θ-Al2O3) and the impregnation solution to obtain Pd-Ag / Al2O3 catalyst precursor III; after aging III in air for 4h, calcined at 450 ° C to obtain Pd 0.01wt% Ag10wt% / Al2O3 carbon monoxide refining catalyst.

[0052] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.01wt% Ag 10wt% / Al2O3 catalyst; reaction pressure of 0.3MPa; reaction temperature of 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity of 4000h -1 .

[0053] Example 7

[0054] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.3wt% Cu 0.5wt% / Al2O3 content is prepared by the following specific steps: Pd(NO3)2 and Cu(NO3)2 are selected to prepare an impregnation solution at 25°C according to the loading amount; 100g of γ-Al2O3 is calcined at 900°C for 6h; after cooling to 25°C, spherical ε-Al2O3 (including part of θ-Al2O3) is obtained and fully mixed with the impregnation solution to obtain Pd-Cu / Al2O3 catalyst precursor III; after aging III in air for 4h, Pd is calcined at 450°C to obtain 0.3wt% Cu 0.5wt% / Al2O3 carbon monoxide refining catalyst.

[0055] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.3wt% Cu 0.5wt% / Al2O3 catalyst; reaction pressure of 0.3MPa; reaction temperature of 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity of 4000h -1 .

[0056] Example 8

[0057] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.5wt% Cu 0.05wt% / Al2O3 content is prepared by the following specific steps: Pd(NO3)2 and Cu(NO3)2 are selected to prepare an impregnation solution at 25°C according to the loading amount; 100g of γ-Al2O3 is calcined at 900°C for 6h; after cooling to 25°C, spherical ε-Al2O3 (including part of θ-Al2O3) is obtained and fully mixed with the impregnation solution to obtain Pd-Cu / Al2O3 catalyst precursor III; after aging III in air for 4h, Pd is calcined at 450°C to obtain 0.5wt% Cu 0.05wt% / Al2O3 carbon monoxide refining catalyst.

[0058] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.5wt% Cu 0.05wt% / Al2O3 catalyst; reaction pressure of 0.3MPa; reaction temperature of 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity of 4000h -1 .

[0059] Example 9

[0060] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.5wt% Cu 0.3wt% / Al2O3 content is prepared by the following specific steps: Pd(NO3)2 and Cu(NO3)2 are selected to prepare an impregnation solution at 25°C according to the loading amount; 100g of γ-Al2O3 is calcined at 900°C for 6h; after cooling to 25°C, spherical ε-Al2O3 (including part of θ-Al2O3) is obtained and fully mixed with the impregnation solution to obtain Pd-Cu / Al2O3 catalyst precursor III; after aging III in air for 4h, Pd is calcined at 450°C to obtain 0.5wt% Cu 0.3wt% / Al2O3 carbon monoxide refining catalyst.

[0061] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.5wt% Cu 0.3wt% / Al2O3 catalyst; reaction pressure of 0.3MPa; reaction temperature of 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity of 4000h -1 .

[0062] Example 10

[0063] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.5wt% Cu 0.5wt% / Al2O3 content is prepared by the following specific steps: Pd(NO3)2 and Cu(NO3)2 are selected to prepare an impregnation solution at 25°C according to the loading amount; 100g of γ-Al2O3 is calcined at 900°C for 6h; after cooling to 25°C, spherical ε-Al2O3 (including part of θ-Al2O3) is obtained and fully mixed with the impregnation solution to obtain Pd-Cu / Al2O3 catalyst precursor III; after aging III in air for 4h, Pd is calcined at 450°C to obtain 0.5wt% Cu 0.5wt% / Al2O3 carbon monoxide refining catalyst.

[0064] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.5% Cu 0.5% / Al2O3 catalyst; reaction pressure of 0.3MPa; reaction temperature of 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity of 4000h -1 .

[0065] Embodiment 11

[0066] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.5wt% Cu 1.0wt% / Al2O3 content is prepared by the following specific steps: Pd(NO3)2 and Cu(NO3)2 are selected to prepare an impregnation solution at 25°C according to the loading amount; 100g of γ-Al2O3 is calcined at 900°C for 6h; after cooling to 25°C, spherical ε-Al2O3 (including part of θ-Al2O3) is obtained and fully mixed with the impregnation solution to obtain Pd-Cu / Al2O3 catalyst precursor III; after aging III in air for 4h, Pd is calcined at 450°C to obtain 0.5wt% Cu 1.0wt% / Al2O3 carbon monoxide refining catalyst.

[0067] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.5wt% Cu 1.0wt% / Al2O3 catalyst; reaction pressure of 0.3MPa; reaction temperature of 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity of 4000h -1 .

[0068] Example 12

[0069] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.01wt% Cu 10wt% / Al2O3 content is prepared by the following specific steps: Pd(NO3)2 and Cu(NO3)2 are selected to prepare an impregnation solution at 25°C according to the loading amount; 100g of γ-Al2O3 is calcined at 900°C for 6h; after cooling to 25°C, spherical ε-Al2O3 (including part of θ-Al2O3) is obtained and fully mixed with the impregnation solution to obtain Pd-Cu / Al2O3 catalyst precursor III; after aging III in air for 4h, Pd is calcined at 450°C to obtain 0.01wt% Cu 10wt% / Al2O3 carbon monoxide refining catalyst.

[0070] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.01wt% Cu 10wt% / Al2O3 catalyst; reaction pressure of 0.3MPa; reaction temperature of 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity of 4000h -1 .

[0071] Example 13

[0072] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.3wt% Mo 0.5wt% / Al2O3 content is prepared by the following specific steps: Pd(NO3)2 and Mo(NO3)4 are selected to prepare an impregnation solution 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 (including part of θ-Al2O3) is obtained and fully mixed with the impregnation solution to obtain Pd-Mo / Al2O3 catalyst precursor III; after aging III in air for 4h, Pd is calcined at 450°C to obtain 0.3wt% Mo 0.5wt% / Al2O3 carbon monoxide refining catalyst.

[0073] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.3wt% Mo 0.5wt% / Al2O3 catalyst; reaction pressure: 0.3MPa; reaction temperature: 200℃; gas: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity is 4000h -1 .

[0074] Embodiment 14

[0075] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.5wt% Mo 0.05wt% / Al2O3 content is prepared by the following specific steps: Pd(NO3)2 and Mo(NO3)4 are selected to prepare an impregnation solution 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 (including part of θ-Al2O3) is obtained and fully mixed with the impregnation solution to obtain Pd-Mo / Al2O3 catalyst precursor III; after aging III in air for 4h, Pd is calcined at 450°C to obtain 0.3wt% Mo 0.05wt% / Al2O3 carbon monoxide refining catalyst.

[0076] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.5wt% Mo 0.05wt% / Al2O3 catalyst; reaction pressure: 0.3MPa; reaction temperature: 200℃; gas: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity is 4000h -1 .

[0077] Embodiment 15

[0078] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.5wt% Mo 0.3wt% / Al2O3 content is prepared by the following specific steps: Pd(NO3)2 and Mo(NO3)4 are selected to prepare an impregnation solution 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 (including part of θ-Al2O3) is obtained and fully mixed with the impregnation solution to obtain Pd-Mo / Al2O3 catalyst precursor III; after aging III in air for 4h, Pd is calcined at 450°C to obtain 0.3wt% Mo 0.3wt% / Al2O3 carbon monoxide refining catalyst.

[0079] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.5wt% Mo 0.3wt% / Al2O3 catalyst; reaction pressure: 0.3MPa; reaction temperature: 200℃; gas: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity is 4000h -1 .

[0080] Example 16

[0081] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.5wt% Mo 0.5wt% / Al2O3 content is prepared by the following specific steps: Pd(NO3)2 and Mo(NO3)4 are selected to prepare an impregnation solution 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 (including part of θ-Al2O3) is obtained and fully mixed with the impregnation solution to obtain Pd-Mo / Al2O3 catalyst precursor III; after aging III in air for 4h, Pd is calcined at 450°C to obtain 0.3wt% Mo 0.5wt% / Al2O3 carbon monoxide refining catalyst.

[0082] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.5wt% Mo 0.5wt% / Al2O3 catalyst; reaction pressure: 0.3MPa; reaction temperature: 200℃; gas: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity is 4000h -1 .

[0083] Embodiment 17

[0084] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.5wt% Mo 1.0wt% / Al2O3 content is prepared by the following specific steps: Pd(NO3)2 and Mo(NO3)4 are selected to prepare an impregnation solution 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 (including part of θ-Al2O3) is obtained and fully mixed with the impregnation solution to obtain Pd-Mo / Al2O3 catalyst precursor III; after aging III in air for 4h, Pd is calcined at 450°C to obtain 0.5wt% Mo1.0wt% / Al2O3 carbon monoxide refining catalyst.

[0085] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.5wt% Mo 1.0wt% / Al2O3 catalyst; reaction pressure: 0.3MPa; reaction temperature: 200℃; gas: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity is 4000h -1 .

[0086] Embodiment 18

[0087] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.01wt% Mo 10wt% / Al2O3 content is prepared by the following specific steps: Pd(NO3)2 and Mo(NO3)4 are selected to prepare an impregnation solution 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 (including part of θ-Al2O3) is obtained and fully mixed with the impregnation solution to obtain Pd-Mo / Al2O3 catalyst precursor III; after aging III in air for 4h, Pd is calcined at 450°C to obtain 0.01wt% Mo 10wt% / Al2O3 carbon monoxide refining catalyst.

[0088] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.01wt% Mo 10wt% / Al2O3 catalyst; reaction pressure: 0.3MPa; reaction temperature: 200℃; gas: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity is 4000h -1 .

[0089] Comparative Example 1

[0090] According to the literature [Qiao, L. et al . ChemCatChem8, 1909-1914 (2016).】Method, 0.089g palladium chloride was weighed and dissolved in 10ml deionized water to prepare a solution with a concentration of 0.05mol / L, and the pH of the solution was adjusted to 1 with hydrochloric acid with a concentration of 1mol / L to obtain solution A. 5.3g of γ-A12O3 with a diameter of 0.3~0.5mm was weighed, and the carrier was impregnated in the prepared solution for 4h. After the impregnation was complete, the residual liquid was filtered out to obtain catalyst precursor B. Precursor B was vacuum calcined at 400℃ for 4h, and then microwaved at 3kw power for 0.1h to obtain catalyst precursor C. Catalyst precursor C was treated at 150℃ for 1h in a mixed atmosphere of H2O / H2 / Ar (H2O / content 0.5%, H2 content 10%) to prepare CU-PdCl X / Al2O3 catalyst.

[0091] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g CU-PdCl X / Al2O3 catalyst; reaction pressure of 0.3MPa; reaction temperature of 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity of 4000h -1 .

[0092] Comparative Example 2

[0093] According to the method of patent CN105618042A, 10g of alumina carrier is weighed and calcined at 300°C in a muffle furnace to obtain an activated alumina carrier. 10ml of lanthanum nitrate solution with a concentration of 0.08mol / L is added dropwise to 10g of activated alumina carrier, impregnated at room temperature for 6h, dried in an oven at 120°C for 15h, placed in a muffle furnace and calcined at 450°C for 5h, cooled to room temperature, and a La-doped catalyst precursor is obtained. 10ml of palladium nitrate solution with a concentration of 0.10mol / L is added dropwise to 10g of catalyst precursor, impregnated at room temperature for 6h, dried in an oven at 120°C for 15h, and calcined at 300°C for 3h to obtain PdO / LaOx-Al2O3 catalyst.

[0094] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g PdO / LaO x -Al2O3 catalyst; reaction pressure 0.3MPa; reaction temperature 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas volume ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity 4000h -1 .

[0095] Comparative Example 3

[0096] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.5wt% / Al2O3 content is prepared by the following specific steps: Pd(NO3)2 is selected to prepare an impregnation solution 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 (including part of θ-Al2O3) is obtained and fully mixed with the impregnation solution to obtain Pd / Al2O3 catalyst precursor III; III is aged in air for 4h and then calcined at 450°C to obtain Pd 0.5wt% / Al2O3 carbon monoxide refining catalyst.

[0097] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.5% / Al2O3 catalyst; reaction pressure of 0.3MPa; reaction temperature of 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity of 4000h -1 .

[0098] Comparative Example 4

[0099] Weigh 100g of alumina carrier (γ-Al2O3), calculated as metal element (the same below), according to Pd 0.3wt% Fe 0.5wt% / Al2O3 content is prepared by the following specific steps: Pd(NO3)2 and Fe(NO3) are selected to prepare an impregnation solution 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 (including part of θ-Al2O3) is obtained and fully mixed with the impregnation solution to obtain Pd-Cu / Al2O3 catalyst precursor III; after aging III in air for 4h, Pd is calcined at 450°C to obtain 0.3wt% Fe 0.5wt% / Al2O3 carbon monoxide refining catalyst.

[0100] The catalytic evaluation was carried out in a fixed bed reactor. The specific conditions are as follows: 5g Pd 0.3wt% Fe 0.5wt% / Al2O3 catalyst; reaction pressure of 0.3MPa; reaction temperature of 200℃; gas introduced: raw gas and O2 gas, wherein the raw gas molar ratio CO:H2=99.5%:0.1%, the molar ratio of H2 to O2 is 1:4; gas space velocity of 4000h -1 .

[0101] The specific example results and comparative example results are shown in Table 1 below.

[0102] Table 1

[0103] serial number catalyst <![CDATA[Residual amount of H2 (ppm)]]> CO loss rate (%) Whether alloy is formed Example 1 <h2 style=";text-align:left;direction:ltr"><![CDATA[Pd <h2 style=";text-align:left;direction:ltr"> 0.3wt% <h2 style=";text-align:left;direction:ltr"> Ag<h2 style=";text-align:left;direction:ltr"> 0.5wt% <h2 style=";text-align:left;direction:ltr"> / Al2O3]]><h2 style=";text-align:left;direction:ltr"> 2 0.17 yes Example 2 <h2 style=";text-align:left;direction:ltr"><![CDATA[Pd <h2 style=";text-align:left;direction:ltr"> 0.5wt% <h2 style=";text-align:left;direction:ltr"> Ag<h2 style=";text-align:left;direction:ltr"> 0.05wt% <h2 style=";text-align:left;direction:ltr"> / Al2O3]]><h2 style=";text-align:left;direction:ltr"> 20 0.33 yes Example 3 <h2 style=";text-align:left;direction:ltr"><![CDATA[Pd <h2 style=";text-align:left;direction:ltr"> 0.5wt% <h2 style=";text-align:left;direction:ltr"> Ag<h2 style=";text-align:left;direction:ltr"> 0.3wt% <h2 style=";text-align:left;direction:ltr"> / Al2O3]]><h2 style=";text-align:left;direction:ltr"> 3 0.21 yes Example 4 <h2 style=";text-align:left;direction:ltr"><![CDATA[Pd <h2 style=";text-align:left;direction:ltr"> 0.5wt% <h2 style=";text-align:left;direction:ltr"> Ag<h2 style=";text-align:left;direction:ltr"> 0.5wt% <h2 style=";text-align:left;direction:ltr"> / Al2O3]]><h2 style=";text-align:left;direction:ltr"> 8 0.31 yes Example 5 <h2 style=";text-align:left;direction:ltr"><![CDATA[Pd <h2 style=";text-align:left;direction:ltr"> 0.5wt% <h2 style=";text-align:left;direction:ltr"> Ag<h2 style=";text-align:left;direction:ltr"> 1.0wt% <h2 style=";text-align:left;direction:ltr"> / Al2O3]]><h2 style=";text-align:left;direction:ltr"> 6 0.66 yes Example 6 <h2 style=";text-align:left;direction:ltr"><![CDATA[Pd <h2 style=";text-align:left;direction:ltr"> 0.01wt% <h2 style=";text-align:left;direction:ltr"> Ag<h2 style=";text-align:left;direction:ltr"> 10wt% <h2 style=";text-align:left;direction:ltr"> / Al2O3]]><h2 style=";text-align:left;direction:ltr"> 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 Embodiment 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 Embodiment 14 <![CDATA[Pd 0.5wt% Mo 0.05wt% / Al2O3]]> 36 0.54 yes Embodiment 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 Embodiment 17 <![CDATA[Pd 0.5wt% Mo 1.0wt% / Al2O3]]> 57 0.88 yes Embodiment 18 <![CDATA[Pd 0.01wt% Mo 10wt% / Al2O3]]> 61 0.48 yes Comparative Example 1 <h2 style=";text-align:left;direction:ltr"><![CDATA[CU-PdCl <h2 style=";text-align:left;direction:ltr"> X <h2 style=";text-align:left;direction:ltr"> / Al2O3]]><h2 style=";text-align:left;direction:ltr"> 10 1.56 no Comparative Example 2 <h2 style=";text-align:left;direction:ltr"><![CDATA[PdO / LaO <h2 style=";text-align:left;direction:ltr"> x <h2 style=";text-align:left;direction:ltr"> -Al2O3]]><h2 style=";text-align:left;direction:ltr"> 38 3.83 no Comparative Example 3 <h2 style=";text-align:left;direction:ltr"><![CDATA[Pd <h2 style=";text-align:left;direction:ltr"> 0.5wt% <h2 style=";text-align:left;direction:ltr"> / Al2O3]]><h2 style=";text-align:left;direction:ltr"> 17 0.80 no Comparative Example 4 <h2 style=";text-align:left;direction:ltr"><![CDATA[Pd <h2 style=";text-align:left;direction:ltr"> 0.3wt% <h2 style=";text-align:left;direction:ltr"> Fe<h2 style=";text-align:left;direction:ltr"> 0.5wt% <h2 style=";text-align:left;direction:ltr"> / Al2O3]]><h2 style=";text-align:left;direction:ltr"> 101 1.07 yes

[0104] It can be seen from Examples 1 to 18 that the residual H2 content meets the requirements of high-purity CO, and the CO loss rate is also less than 1%. In all the examples using auxiliary metals, PdM single-atom alloy particles are successfully formed. This shows that the present invention can better solve the problem of excessive consumption of carbon monoxide when removing hydrogen from carbon monoxide and producing high-purity carbon monoxide by oxygen oxidation.

[0105] Although the catalyst in Comparative Example 1 has low residual hydrogen content, the catalyst preparation steps are complicated and the CO loss rate is high.

[0106] The catalyst in Comparative Example 2 uses rare earth elements as additives, the catalyst cost is high, and the CO loss rate is high.

[0107] The catalyst in Comparative Example 3 contains only Pd without adding any promoter metal, and has poor catalytic performance, which indicates that the addition of promoter metal is necessary to improve the catalytic performance.

[0108] Although the catalyst in Comparative Example 4 formed an alloy, an unsuitable auxiliary metal Fe was selected, resulting in extremely high H2 residual content and poor catalytic performance.

[0109] The catalyst in Example 1 greatly destroys the {111} crystal plane of Pd that can activate CO, and only retains the Pd single atom that can effectively activate H2 to the greatest extent, so that when CO is adsorbed on Pd in ​​a linear manner, desorption occurs before oxidation, CO will not be oxidized, and extremely low H2 residual amount and CO loss rate are achieved. Compared with other examples and comparative examples, Example 1 shows a good balance in catalytic performance, cost-effectiveness and preparation feasibility.

[0110] The above is only a preferred embodiment of the present invention, and is not intended to limit the implementation methods. It should be noted that, for ordinary technicians in the relevant field, some improvements and modifications can be made 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 a carrier alumina, an active ingredient palladium Pd and an auxiliary metal M. The active ingredient palladium Pd is dispersed in the form of single atoms on the surface of the auxiliary metal M to form PdM single atom alloy particles loaded on the carrier alumina. Based on the mass of the carrier alumina in the catalyst, the content of the active ingredient palladium Pd is 0.01% to 0.5% of the weight of the carrier, and the content of the auxiliary metal M is 0.05% to 10% of the weight of the carrier. The auxiliary metal M is selected from any one of silver, copper, molybdenum, zinc, tin or indium.

2. The carbon monoxide purification catalyst according to claim 1, characterized in that The carrier alumina is a mixed crystal of ε-Al2O3 and θ-Al2O3. Based on the mass of the carrier alumina in the catalyst, the content of ε-Al2O3 is 60% to 80% of the carrier weight.

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

4. The carbon monoxide purification catalyst according to claim 3, characterized in that: Based on the weight of the carrier alumina in the catalyst, the content of the active ingredient palladium Pd is 0.3% of the weight of the carrier, and the content of silver is 0.5% of the weight of the carrier.

5. The carbon monoxide purification catalyst according to claim 4, characterized in that: The particle size of the palladium-silver (PdAg) single-atom alloy particles ranges from 4 to 6 nm.

6. A method for preparing a carbon monoxide refining catalyst according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: Mixing a soluble palladium salt and a salt solution of an auxiliary metal to prepare an impregnation solution; The starting alumina γ-Al2O3 is calcined at 600°C to 1000°C for 4 to 8 hours, and then cooled to 25°C to obtain a spherical mixed crystal carrier alumina; wherein the mixed crystal carrier alumina is ε-Al2O3 and θ-Al2O3, and the content of the ε-Al2O3 is 60% to 80% of the carrier weight based on the weight of the carrier alumina in the catalyst; The mixed crystal carrier alumina and the impregnation solution are fully mixed to obtain a PdM / Al2O3 catalyst precursor; The catalyst precursor is aged and calcined in air to obtain the carbon monoxide purification catalyst.

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

8. The preparation method according to claim 6, characterized in that: The salt solution of the auxiliary metal is selected from any one of nitrate, sulfate, carbonate or chloride.

9. The preparation method according to claim 6, characterized in that: The volume range of the spherical mixed crystal carrier alumina is 0.1mm 3 ~10cm 3 .

10. The preparation method according to claim 6, characterized in that: 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.

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