Bi-metal additive modified copper-based catalyst as well as preparation method and application thereof

Abstract

The invention discloses a bimetallic auxiliary agent modified copper-based catalyst as well as a preparation method and application thereof. The catalyst comprises a carrier as well as an active component, a first auxiliary agent metal M1 and a second auxiliary agent metal M2 which are loaded on the carrier, the active component is metal Cu, and the loading capacity is 5-6wt% of the total mass of the catalyst; the first assistant metal M1 is selected from at least one of alkali metal or alkaline earth metal elements, and the loading capacity is 0.5-3wt% of the total mass of the catalyst; the second auxiliary agent metal M2 is at least one of transition metal elements, and the loading capacity is 0.5-3wt% of the total mass of the catalyst. The catalyst prepared by the invention shows excellent performance in acetylene selective hydrogenation reaction and shows relatively good stability. The catalyst is based on non-noble metal, the preparation process is simple, and the cost is low. The core innovation of the invention lies in providing a bimetallic auxiliary agent using a specific combination, effectively solving the problem of inactive electronic structure stability of a Cu-based catalyst, and having significant industrial application potential.

Description

Technical Field

[0001] This invention relates to a copper-based catalyst modified with a bimetallic additive, its preparation method, and its application. Background Technology

[0002] Currently, ethylene is mainly produced industrially through the steam cracking of petroleum hydrocarbons. The ethylene products generated in this process often contain small amounts of acetylene impurities. These impurities can irreversibly poison the Ziegler-Natta catalyst used in downstream polymerization stages, significantly affecting the quality of the final polymerization product. Therefore, polyethylene production requires that the acetylene concentration in the raw ethylene feedstock be below 1 ppm (ACS Catal. 2023, 13: 1952–1963).

[0003] Selective hydrogenation of acetylene is a crucial process for purifying ethylene feedstock. While traditional palladium-based catalysts possess some activity, they are expensive and exhibit low ethylene selectivity, easily leading to over-hydrogenation and ethane formation, making it difficult to simultaneously meet the requirements of high selectivity and economic efficiency (ACS Catal. 2020, 10, 17, 9694–9705). In contrast, copper-based non-precious metal catalysts are considered ideal alternatives due to their excellent ethylene selectivity and lower cost (ACS Catal. 2024, 14, 8, 5838–5846, CN115722223A). However, copper-based catalysts exhibit poor structural stability in actual reaction atmospheres, readily undergoing surface reconstruction or phase transitions, leading to degradation of the active component Cu. + Excessive reduction to inert Cu 0 This weakens the adsorption and activation capacity of reactants such as acetylene, resulting in rapid catalyst deactivation (J. Phys. Chem. C 2022, 126, 44, 18645–18651).

[0004] To address the aforementioned problems, this invention proposes a bimetallic promoter synergistic regulation strategy. By coupling the electronic and structural effects of the two metal promoters, the stability of Cu-based catalysts in the selective hydrogenation of acetylene is significantly enhanced. This catalyst system can achieve continuous stable operation for over 30 hours under high space velocity (36000 h⁻¹) conditions, with an average deactivation rate as low as 0.06% / h, while maintaining an ethylene selectivity above 95%. This invention has significant industrial application value and provides new ideas for the design of next-generation, efficient, and stable acetylene hydrogenation catalysts. Summary of the Invention

[0005] In view of the above-mentioned technical problems existing in the prior art, the purpose of the present invention is to provide a copper-based catalyst modified with bimetallic additives, its preparation method and application, and to provide a reliable solution for effectively inhibiting the deactivation of Cu-based catalysts and improving their stability by using a specific combination of bimetallic additives to stabilize the electronic state of the active center copper.

[0006] The technical solution adopted in this invention is as follows:

[0007] A copper-based catalyst modified with a bimetallic additive includes a support and an active component supported on the support, a first additive metal M1 and a second additive metal M2;

[0008] The active component is metallic Cu, and the loading is 5-6 wt% of the total mass of the catalyst;

[0009] The first auxiliary metal M1 is selected from at least one alkali metal or alkaline earth metal element, and the loading is 0.5 to 3 wt% of the total mass of the catalyst.

[0010] The second auxiliary metal M2 is at least one of the transition metal elements, and its loading is 0.5 to 3 wt% of the total mass of the catalyst.

[0011] Furthermore, the first auxiliary metal M1 is selected from at least one of K, Mg, Ca, Sr, and Ba, and the second auxiliary metal M2 is selected from at least one of Ni, Zn, Co, Mn, and Fe.

[0012] Furthermore, the carrier is one or more of silica, aluminum oxide, diatomaceous earth, and borax.

[0013] The method for preparing a copper-based catalyst modified with a bimetallic additive includes the following steps:

[0014] 1) Dissolve the copper source completely in the solvent, add ammonia to adjust the pH of the solution to 7-13, and obtain solution A;

[0015] 2) The carrier is dispersed in a solvent to obtain mixture B;

[0016] 3) Mix solution A with mixture B and stir vigorously for 4 hours; then heat to 70-90℃, adjust the pH of the mixture to 7-8, centrifuge, dry, and calcine in a muffle furnace to obtain the copper-based catalyst precursor;

[0017] 4) The metal M1 source and the metal M2 source are dissolved in deionized water and impregnated onto the copper-based catalyst precursor in equal volumes. After drying, they are calcined in a muffle furnace and finally reduced by calcination under H2 atmosphere to obtain the copper-based catalyst modified by the bimetallic additive.

[0018] Further, in step 1), the copper source is one or more of copper chloride, cuprous chloride, copper sulfate, copper nitrate, copper carbonate, basic copper carbonate, and copper acetate, and the solvent is one or more of deionized water, anhydrous ethanol, acetone, DMF, and chloroform.

[0019] Furthermore, in step 3) or step 4), the calcination temperature in the muffle furnace is 400-500℃, and the calcination time is 2-6h.

[0020] Furthermore, the metal source M1 and the metal source M2 are each selected from the sulfate, nitrate or chloride salt of the corresponding metal. The calcination and reduction temperature in step 4) is 250-350℃ and the reduction time is 2-6h.

[0021] This invention also discloses the application of a copper-based catalyst modified with a bimetallic additive in the selective hydrogenation reaction. The catalyst catalyzes the acetylene semi-hydrogenation reaction under the following conditions: temperature 180-220℃, pressure 0.1-1 MPa (preferably 0.1-0.3 MPa, more preferably atmospheric pressure), feedstock consisting of hydrogen and acetylene in a volume ratio of 1-2:1, and space velocity 10000-100000 mL·g. -1 ·h -1 .

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] (1) Compared with noble metal-based catalysts, the dual-additive modified copper-based catalyst of the present invention has a significant advantage in terms of cost; at the same time, compared with the problem that noble metal active sites have strong hydrogenolysis ability and are prone to over-hydrogenation leading to a decrease in selectivity, the present invention effectively suppresses side reactions and maintains high ethylene selectivity.

[0024] (2) Compared with copper-based catalysts modified by a single promoter (such as transition metals or alkaline earth metals), this invention introduces a dual promoter synergistic mechanism, overcoming the problems of limited electronic structure modification ability, insufficient activity enhancement, and poor hydrothermal stability when using single-component regulation. The catalyst preparation process used in this invention is simple, low-cost, safe, and efficient, while achieving synergistic optimization between activity, selectivity, and stability, demonstrating strong industrial applicability and promising prospects for widespread application.

[0025] (3) The catalyst prepared in this invention exhibits excellent performance in the selective hydrogenation of acetylene. At a catalytic reaction temperature of 200℃ and a high space velocity (18000 ml / gcat·h), it achieves an acetylene conversion of >95% and an ethylene selectivity of >95%, while also demonstrating good stability. This catalyst is based on non-precious metals, and its preparation process is simple and low-cost. Its core innovation lies in providing a bimetallic promoter with a specific combination, which effectively solves the problem of electronic structure stability in Cu-based catalyst deactivation, and has significant potential for industrial application. Attached Figure Description

[0026] Figure 1 The reaction results of the catalysts in Examples 1-4 at different catalytic times;

[0027] Figure 2 This refers to the reaction results using catalysts with different Ca loadings at different catalytic times as described in Example 4.1.

[0028] Figure 3 This is a comparison of acetylene conversion and ethylene selectivity using catalysts with different Ni loadings in Example 4.2 at a catalytic time of 3 h.

[0029] Figure 4 This is the result of a long-term catalytic reaction using the catalyst in Example 4 for the acetylene semi-hydrogenation reaction;

[0030] Figure 5 This is a comparison of the CO-DRIFTS diagrams of the catalysts in Example 2 and Example 4 after catalytic reaction times of 1 h, 2 h, and 3 h.

[0031] Figure 6 This is a high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) image of the catalyst in Example 4 after 20 hours of catalyst reaction. Detailed Implementation

[0032] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0033] Example 1

[0034] 7.87×10 -4 A precursor solution was prepared by dissolving mol Cu(NO3)2·3H2O in 5 mL of deionized water. Ammonia solution was added dropwise to the precursor solution while maintaining pH > 9; this solution was denoted as solution A. Then, 1 g of silica was added to 20 mL of deionized water and mixed thoroughly. Solution A was then poured in, and the mixture was stirred vigorously for 4 h. After stirring, the temperature was raised to 80 °C, the pH was adjusted to 7, and heating was stopped. The mixture was centrifuged and filtered while hot, washed three times with water, and dried at 80 °C for 8 h. The dried product was placed in a muffle furnace and calcined at 450 °C for 4 h. The catalyst was then reduced in an H2 atmosphere at 300 °C for 4 h to obtain the catalyst, named the 5% Cu-AE catalyst.

[0035] Example 2

[0036] 7.87×10 -41 mol Cu(NO3)2·3H2O was dissolved in 5 mL of deionized water to prepare a precursor solution. Ammonia solution was added dropwise to the precursor solution while maintaining pH > 9, denoted as solution A. Then, 1 g of silica was added to 20 mL of deionized water and mixed thoroughly. Solution A was then poured in, and the mixture was stirred vigorously for 4 h. After stirring, the temperature was raised to 80 °C, the pH was adjusted to 7, and heating was stopped. The mixture was centrifuged and filtered while hot, washed three times with water, and dried at 80 °C for 8 h. The dried product was then placed in a muffle furnace and calcined at 450 °C for 4 h to obtain the catalyst precursor. Then, 1.7 × 10⁻⁶ mol Cu(NO3)₂·3H₂O was added to the precursor solution. -4 1 mol NiSO4·6H2O was dissolved in 3.2 mL of water, and the resulting solution was used to impregnate 1 g of catalyst precursor with an equal volume. The solution was then placed in a vacuum oven and dried at 80 °C for 6 h. The resulting sample was placed in a muffle furnace and calcined at 350 °C for 4 h. Subsequently, the catalyst was reduced at 300 °C for 4 h under H2 atmosphere to obtain the desired copper-based catalyst, named the 1% Ni / 5% Cu-AE catalyst.

[0037] Example 3

[0038] 7.87×10 -4 1 mol Cu(NO3)2·3H2O was dissolved in 5 mL of deionized water to prepare a precursor solution. Ammonia solution was added dropwise to the precursor solution while maintaining pH > 9, denoted as solution A. Then, 1 g of silica was added to 20 mL of deionized water and mixed thoroughly. Solution A was then poured in, and the mixture was stirred vigorously for 4 h. After stirring, the temperature was raised to 80 °C, the pH was adjusted to 7, and heating was stopped. The mixture was centrifuged and filtered while hot, washed three times with water, and dried at 80 °C for 8 h. The dried product was then placed in a muffle furnace and calcined at 450 °C for 4 h to obtain the catalyst precursor. Then, 2.49 × 10⁻⁶ mol Cu(NO3)₂·3H₂O was added to the precursor solution. -4 mol CaCl2 was dissolved in 3.2 mL of water, and the resulting solution was used to impregnate 1 g of catalyst precursor with an equal volume. The solution was then placed in a vacuum oven and dried at 80 °C for 6 h. The resulting sample was placed in a muffle furnace and calcined at 350 °C for 4 h. Subsequently, the catalyst was reduced at 300 °C for 4 h under H2 atmosphere to obtain the desired copper-based catalyst, named the 1% Ca / 5% Cu-AE catalyst.

[0039] Example 4

[0040] 7.87×10 -4 Cu(NO3)2·3H2O was dissolved in 5 mL of deionized water to prepare a precursor solution. Ammonia solution was added dropwise to the precursor solution while maintaining pH > 9, denoted as solution A. Then, 1 g of silica was added to 20 mL of deionized water and mixed thoroughly. Solution A was then poured in, and the mixture was stirred vigorously for 4 h. After stirring, the temperature was raised to 80 °C, the pH was adjusted to 7, and heating was stopped. The mixture was centrifuged and filtered while hot, washed three times with water, and dried at 80 °C for 8 h. The dried product was placed in a muffle furnace and calcined at 450 °C for 4 h to obtain the catalyst precursor. Then, 2.55 × 10⁻⁶...-4 mol NiSO4·6H2O and 2.49×10 -4 mol CaCl2 was dissolved in 3.2 mL of water, and the resulting solution was used to impregnate 1 g of catalyst precursor with an equal volume. The solution was then placed in a vacuum oven and dried at 80 °C for 6 h. The resulting sample was placed in a muffle furnace and calcined at 350 °C for 4 h. Subsequently, the catalyst was reduced at 300 °C for 4 h under H2 atmosphere to obtain the desired copper-based catalyst, named (1.5% Ni-1% Ca) / 5% Cu-AE catalyst.

[0041] Example 4.1

[0042] Example 4.1 Catalyst Preparation Method: This method repeats Example 4, except that the amount of CaCl2 used is replaced with 1.245 × 10⁻⁶. -4 mol, 2.49 × 10 -4 mol, 3.735 × 10 -4 mol or 4.98 × 10 -4 With all other conditions unchanged, catalysts with Ca loadings of 0.5 wt%, 1 wt%, 1.5 wt%, and 2 wt% were obtained. The four catalysts were named (1.5% Ni-0.5% Ca) / 5% Cu-AE, (1.5% Ni-1% Ca) / 5% Cu-AE, (1.5% Ni-1.5% Ca) / 5% Cu-AE, and (1.5% Ni-2% Ca) / 5% Cu-AE, respectively.

[0043] Example 4.2

[0044] Example 4.2 Catalyst Preparation Method: This method repeats Example 4, except that the amount of NiSO4·6H2O is replaced with 0.85 × 10⁻⁶. -4 mol, 1.7 × 10 -4 mol, 2.55 × 10 -4 mol or 3.4 × 10 -4 With all other conditions unchanged, catalysts with Ni loadings of 0.5 wt%, 1 wt%, 1.5 wt%, and 2 wt% were obtained, and the four catalysts were named (0.5% Ni-1% Ca) / 5% Cu-AE, (1.0% Ni-1% Ca) / 5% Cu-AE, (1.5% Ni-1% Ca) / 5% Cu-AE, and (2.0% Ni-1% Ca) / 5% Cu-AE, respectively.

[0045] Example 5

[0046] 7.87×10 -4Cu(NO3)2·3H2O was dissolved in 5 mL of deionized water to prepare a precursor solution. Ammonia solution was added dropwise to the precursor solution while maintaining pH > 9, denoted as solution A. Then, 1 g of silica was added to 20 mL of deionized water and mixed thoroughly. Solution A was then poured in, and the mixture was stirred vigorously for 4 h. After stirring, the temperature was raised to 80 °C, the pH was adjusted to 7, and heating was stopped. The mixture was centrifuged and filtered while hot, washed three times with water, and dried at 80 °C for 8 h. The dried product was placed in a muffle furnace and calcined at 450 °C for 4 h to obtain the catalyst precursor. Then, 2.55 × 10⁻⁶... -4 mol NiSO4·6H2O and 2.56×10 -4 mol KCl was dissolved in 3.2 mL of water, and the resulting solution was used to impregnate 1 g of catalyst precursor with an equal volume. The solution was then placed in a vacuum oven and dried at 80 °C for 6 h. The resulting sample was placed in a muffle furnace and calcined at 350 °C for 4 h. Subsequently, the catalyst was reduced in a H2 atmosphere at 300 °C for 4 h to obtain the desired copper-based catalyst, named (1.5% Ni-1% K) / 5% Cu-AE catalyst.

[0047] Example 6

[0048] 7.87×10 -4 1 mol Cu(NO3)2·3H2O was dissolved in 5 mL of deionized water to prepare a precursor solution. Ammonia solution was added dropwise to the precursor solution while maintaining pH > 9, denoted as solution A. Then, 1 g of silica was added to 20 mL of deionized water and mixed thoroughly. Solution A was then poured in, and the mixture was stirred vigorously for 4 h. After stirring, the temperature was raised to 80 °C, the pH was adjusted to 7, and heating was stopped. The mixture was centrifuged and filtered while hot, washed three times with water, and dried at 80 °C for 8 h. The dried product was placed in a muffle furnace and calcined at 450 °C for 4 h to obtain the catalyst precursor. Then, 2.55 × 10⁻⁶ mol Cu(NO3)₂·3H₂O was added to the precursor solution. -4 mol NiSO4·6H2O and 4.11×10 -4 1 mol of MgCl2 was dissolved in 3.2 mL of water, and the resulting solution was used to impregnate 1 g of catalyst precursor with an equal volume. The solution was then placed in a vacuum oven and dried at 80 °C for 6 h. The resulting sample was placed in a muffle furnace and calcined at 350 °C for 4 h. Subsequently, the catalyst was reduced in a H2 atmosphere at 300 °C for 4 h to obtain the desired copper-based catalyst, named (1.5% Ni-1% Mg) / 5% Cu-AE catalyst.

[0049] Example 7

[0050] 7.87×10 -41 mol Cu(NO3)2·3H2O was dissolved in 5 mL of deionized water to prepare a precursor solution. Ammonia solution was added dropwise to the precursor solution while maintaining pH > 9, denoted as solution A. Then, 1 g of silica was added to 20 mL of deionized water and mixed thoroughly. Solution A was then poured in, and the mixture was stirred vigorously for 4 h. After stirring, the temperature was raised to 80 °C, the pH was adjusted to 7, and heating was stopped. The mixture was centrifuged and filtered while hot, washed three times with water, and dried at 80 °C for 8 h. The dried product was placed in a muffle furnace and calcined at 450 °C for 4 h to obtain the catalyst precursor. Then, 2.55 × 10⁻⁶ mol Cu(NO3)₂·3H₂O was added to the precursor solution. -4 molNiSO4·6H2O and 7.28×10 -5 mol BaCl2 was dissolved in 3.2 mL of water, and the resulting solution was used to impregnate 1 g of catalyst precursor with an equal volume. The solution was then placed in a vacuum oven and dried at 80 °C for 6 h. The resulting sample was placed in a muffle furnace and calcined at 350 °C for 4 h. Subsequently, the catalyst was reduced at 300 °C for 4 h under H2 atmosphere to obtain the desired copper-based catalyst, named (1.5% Ni-1% Ba) / 5% Cu-AE catalyst.

[0051] Example 8

[0052] 7.87×10 -4 1 mol Cu(NO3)2·3H2O was dissolved in 5 mL of deionized water to prepare a precursor solution. Ammonia solution was added dropwise to the precursor solution while maintaining pH > 9, denoted as solution A. Then, 1 g of silica was added to 20 mL of deionized water and mixed thoroughly. Solution A was then poured in, and the mixture was stirred vigorously for 4 h. After stirring, the temperature was raised to 80 °C, the pH was adjusted to 7, and heating was stopped. The mixture was centrifuged and filtered while hot, washed three times with water, and dried at 80 °C for 8 h. The dried product was then placed in a muffle furnace and calcined at 450 °C for 4 h to obtain the catalyst precursor. Then, 2.68 × 10⁻⁶ mol Cu(NO3)₂·3H₂O was added to the precursor solution. -4 mol Fe(NO3)3·9H2O and 2.49×10 -4 mol CaCl2 was dissolved in 3.2 mL of water, and the resulting solution was used to impregnate 1 g of catalyst precursor with an equal volume. The solution was then placed in a vacuum oven and dried at 80 °C for 6 h. The resulting sample was placed in a muffle furnace and calcined at 350 °C for 4 h. Subsequently, the catalyst was reduced in a H2 atmosphere at 300 °C for 4 h to obtain the desired copper-based catalyst, named (1.5% Fe-1% Ca) / 5% Cu-AE catalyst.

[0053] Example 9

[0054] 7.87×10 -41 mol Cu(NO3)2·3H2O was dissolved in 5 mL of deionized water to prepare a precursor solution. Ammonia solution was added dropwise to the precursor solution while maintaining pH > 9, denoted as solution A. Then, 1 g of silica was added to 20 mL of deionized water and mixed thoroughly. Solution A was then poured in, and the mixture was stirred vigorously for 4 h. After stirring, the temperature was raised to 80 °C, the pH was adjusted to 7, and heating was stopped. The mixture was centrifuged and filtered while hot, washed three times with water, and dried at 80 °C for 8 h. The dried product was then placed in a muffle furnace and calcined at 450 °C for 4 h to obtain the catalyst precursor. Then, 2.54 × 10⁻⁶ mol Cu(NO3)₂·3H₂O was added to the precursor solution. -4 mol CoSO4·6H2O and 2.49×10 -4 mol CaCl2 was dissolved in 3.2 mL of water, and the resulting solution was used to impregnate 1 g of catalyst precursor with an equal volume. The solution was then placed in a vacuum oven and dried at 80 °C for 6 h. The resulting sample was placed in a muffle furnace and calcined at 350 °C for 4 h. Subsequently, the catalyst was reduced at 300 °C for 4 h under H2 atmosphere to obtain the desired copper-based catalyst, named (1.5% Co-1% Ca) / 5% Cu-AE catalyst.

[0055] Application Example 1:

[0056] The catalyst powder was compressed into tablets, crushed, and screened to a particle size of 60-80 mesh. The catalyst was then loaded into a fixed-bed reactor for acetylene semi-hydrogenation reaction. The reaction conditions were as follows: the gas feedstock was a C2H2 / H2 mixture with a volume ratio of 1:2; the space velocity of the gas feedstock through the catalyst bed was 18000 ml / g catalyst / h; the pressure was atmospheric; and the catalytic reaction temperature was 200℃.

[0057] The results of using the catalysts of Examples 1-9 for a catalytic reaction time of 2 hours, following the above catalytic reaction process, are shown in Table 1.

[0058] Table 1 Evaluation results of selective hydrogenation of acetylene using supported copper-based catalysts

[0059]

[0060] Following the catalytic reaction process described above, the reaction results using the catalysts from Examples 1-4 at different catalytic times are shown below. Figure 1 As shown, Figure 1 (a) shows the change in acetylene conversion rate with catalytic time. Figure 1 (b) shows the change in ethylene selectivity with catalytic time.

[0061] Following the catalytic reaction process described above, the reaction results using catalysts with different Ca loadings at different catalytic times as described in Example 4.1 are shown below. Figure 2 As shown, Figure 2 (a) shows the change in acetylene conversion rate with catalytic time. Figure 2(b) shows the change in ethylene selectivity with catalytic time.

[0062] Following the catalytic reaction process described above, the comparison results of acetylene conversion and ethylene selectivity using catalysts with different Ni loadings at a catalytic time of 3 h, as shown in Example 4.2, are as follows: Figure 3 As shown.

[0063] Following the catalytic reaction process described above, the long-term catalytic reaction results of the acetylene semi-hydrogenation reaction using the catalyst of Example 4 are shown below. Figure 4 As shown. Example 4: High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image of the catalyst after 20 hours of reaction. Figure 6 As shown, from Figure 6 It can be seen that the copper species at the active center are dispersed in the catalyst in the form of uniformly sized nanoclusters, while the two promoter metals (Ni and Ca) exhibit a broad and uniform coverage on the support surface, forming a tight interfacial interaction with the copper clusters. This unique structure optimizes the electronic environment of the active center, thus jointly contributing to the catalyst's excellent performance of maintaining high activity and high selectivity during long-term reactions.

[0064] Following the catalytic reaction process described above, the catalysts of Example 2 and Example 4 of this invention were characterized after catalytic reaction times of 1 h, 2 h, and 3 h, respectively. The comparison results of their CO-DRIFTS diagrams after different catalytic times are shown below. Figure 5 , Figure 5 (a) The results correspond to the catalyst in Example 2. Figure 5 (b) Results correspond to the catalyst in Example 4. From... Figure 5 The CO-DRIFTS spectrum shows that the peak position of the copper-based catalyst regulated by the single promoter in Example 2 is at 2132 cm⁻¹. -1 Nearby, the location of this peak belongs to Cu. + The adsorption peak position of CO changed irregularly during different reaction times from 1 to 3 hours, indicating that the active sites of the catalyst are dynamically and unstable. Referring to Example 4's description of the dual-promoter regulation of CO-DRIFTS in copper-based catalysts, a decrease in CO absorption frequency generally signifies an enhanced feedback effect of electrons from CO molecular orbitals to empty metal orbitals. The direct cause of this enhancement is the increased electron density at the metal center itself, which is more conducive to stabilizing the catalyst's active centers.

[0065] The contents described in this specification are merely an enumeration of the implementation forms of the inventive concept, and the scope of protection of this invention should not be regarded as limited to the specific forms described in the embodiments.

Claims

1. A copper-based catalyst modified with a bimetallic additive, characterized in that, It includes a carrier and an active component loaded on the carrier, a first auxiliary metal M1, and a second auxiliary metal M2; The active component is metallic Cu, and its loading is 5-6 wt% of the total catalyst mass. The first auxiliary metal M1 is selected from at least one alkali metal or alkaline earth metal element, and its loading is 0.5 to 3 wt% of the total mass of the catalyst. The second auxiliary metal M2 is at least one of the transition metal elements, and its loading is 0.5 to 3 wt% of the total mass of the catalyst.

2. The copper-based catalyst modified with a bimetallic additive as described in claim 1, characterized in that, The first auxiliary metal M1 is selected from at least one of K, Mg, Ca, Sr, and Ba, and the second auxiliary metal M2 is selected from at least one of Ni, Zn, Co, Mn, and Fe.

3. The copper-based catalyst modified with a bimetallic additive as described in claim 1, characterized in that, The carrier is one or more of silica, aluminum oxide, diatomaceous earth, and borax.

4. The method for preparing a copper-based catalyst modified with a bimetallic additive as described in claim 1, characterized in that, Includes the following steps: 1) Dissolve the copper source completely in the solvent, add ammonia to adjust the pH of the solution to 7-13, and obtain solution A; 2) The carrier is dispersed in a solvent to obtain mixture B; 3) Mix solution A with mixture B and stir vigorously for 4 hours; then heat to 70-90℃, adjust the pH of the mixture to 7-8, centrifuge, dry, and calcine in a muffle furnace to obtain a copper-based catalyst precursor; 4) The metal M1 source and the metal M2 source are dissolved in deionized water and impregnated onto the copper-based catalyst precursor in equal volumes. After drying, they are calcined in a muffle furnace and finally reduced by calcination under H2 atmosphere to obtain the copper-based catalyst modified with the bimetallic additive.

5. The method for preparing a copper-based catalyst modified with a bimetallic additive as described in claim 4, characterized in that, In step 1), the copper source is one or more of copper chloride, cuprous chloride, copper sulfate, copper nitrate, copper carbonate, basic copper carbonate, and copper acetate, and the solvent is one or more of deionized water, anhydrous ethanol, acetone, DMF, and chloroform.

6. The method for preparing a copper-based catalyst modified with a bimetallic additive as described in claim 4, characterized in that, In step 3) or step 4), the calcination temperature in the muffle furnace is 400-500℃, and the calcination time is 2-6h.

7. The method for preparing a copper-based catalyst modified with a bimetallic additive as described in claim 4, characterized in that, Metal source M1 and metal source M2 are each selected from the sulfate, nitrate or chloride salt of the corresponding metal. The calcination and reduction temperature in step 4) is 250-350℃ and the reduction time is 2-6h.

8. The application of the copper-based catalyst modified with a bimetallic additive as described in claim 1 in the catalytic selective hydrogenation reaction.

9. The application as described in claim 8, characterized in that... The catalyst catalyzes the semi-hydrogenation reaction of acetylene. The reaction conditions are: temperature 180-220℃, pressure 0.1-0.3MPa, and the feed gas is hydrogen to acetylene in a volume ratio of 1 to 2:1.

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