A catalyst for the direct synthesis of acetic acid and ethanol via a non-hydrogenation route from CO2, its preparation method, and its applications.

Abstract

A catalyst for the direct synthesis of acetic acid and ethanol from CO2 via a non-hydrogenation route, its preparation method, and its application are disclosed. This invention belongs to the field of catalyst technology and overcomes the shortcomings of existing acetic acid synthesis technologies. The solution involves using TiO2 nanotubes as the catalyst support, and the active component being a single metal Co or Pd, or a bimetallic composition of Co and Pd, with a loading of 3-7%. wt The catalyst is prepared by first using a hydrothermal method to prepare TiO2 nanotubes, and then using the TiO2 nanotubes as a carrier, impregnating, drying, and calcining to obtain the catalyst. When applied to a dual-channel fixed-bed step-by-step continuous reactor, the catalyst enables the one-step conversion of CO2 to ethanol and acetic acid via a non-hydrogenation route at low temperature and atmospheric pressure, avoiding the problem of insufficient hydrogen source in the CO2 hydrogenation route. The process of this invention is short, the conditions are mild, it does not require a high-energy-consuming syngas production step, the product composition is simple, and the subsequent separation energy consumption is low.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a catalyst for the direct synthesis of acetic acid and ethanol via a non-hydrogenation route of CO2, its preparation method, and its application. Background Technology

[0002] Acetic acid, as an important chemical intermediate, is widely used in the manufacture of industrial chemicals, such as as a raw material for synthesizing vinyl acetate monomer, cellulose acetate or anhydrous cellulose acetate, acetate esters, and other chemical products, as well as as a solvent for synthesizing terephthalic acid. The main routes for producing acetic acid are methanol carbonylation, and non-carbonylation routes such as acetaldehyde oxidation, direct ethylene oxidation, and direct ethane oxidation. However, due to issues such as numerous byproducts, high energy consumption during purification, and conflicts between process safety and acetic acid productivity, the mainstream commercial method for producing acetic acid remains liquid-phase methanol carbonylation.

[0003] Currently, over 80% of acetic acid is produced via methanol carbonylation using homogeneous Rh or Ir-based catalysts. This process was first commercialized by BASF, and subsequent advancements in the Monsanto, Actica, and Cativa processes have resulted in acetic acid yields exceeding 99%. However, many problems remain to be solved, such as the difficulty in separating homogeneous catalysts from corrosive liquid reaction media and the unavoidable use of iodide promoters. Therefore, researchers have conducted extensive studies on direct or indirect gas-phase processes for acetic acid production in an attempt to address the problems associated with liquid-phase carbonylation. Patent EP2935184B1 discloses an integrated process for synthesizing acetic acid from syngas and dimethyl ether, called the BP-SaaBre process. Compared to traditional homogeneous catalytic processes, the BP-SaaBre process simplifies the energy-intensive methanol and carbon monoxide purification steps and solves the problem of separating noble metal catalysts from corrosive liquid products containing halides. However, neither methanol carbonylation-based processes nor the BP-SaaBre process can bypass the energy-intensive syngas production process.

[0004] The syngas used in the methanol carbonylation reaction is generally obtained through methane steam reforming, and methanol itself is produced from syngas. Therefore, if acetic acid could be directly synthesized from methane at low temperatures, bypassing the syngas production step, the production cost of acetic acid could theoretically be greatly reduced. US7368598 provides a method for the direct and selective conversion of methane to acetic acid in a single step, where methane reacts with a Pt, Pd, Rh, Ru, Os, or Ir-based catalyst and oxidant in an acidic medium (such as H2SO4, O2, H2SeO4, TeO3, H2O2, trifluoroacetic acid, triacetic acid, or ionic liquid). The method depends on the isolated acetic acid... 13C-NMR spectroscopy indicates that both carbons in acetic acid originate from methane. However, even after scaling up the homogeneous reaction system described above, significant separation costs are still required. Therefore, researchers in this field have turned their attention to the direct conversion of methane into acetic acid in heterogeneous catalytic systems.

[0005] CN201910744903 discloses a method for the direct production of methanol and acetic acid from methane. CO, O2, and CH4 are introduced into a batch high-pressure reactor at 100℃ to 250℃ for reaction. The catalyst is a molecular sieve catalyst supported on at least two metal elements (the first component is Au, and the second component is at least one of Pt, Cu, Fe, Co, and Mn). Methanol and acetic acid can be produced.

[0006] CN20211040118 discloses a composite photocatalyst, namely a catalyst composed of a two-dimensional layered transition metal sulfide confined metal single-atom material and a nano-semiconductor, applied to the photocatalytic direct conversion of methane to methanol and acetic acid, with an acetic acid selectivity as high as 96.3%. In the aforementioned heterogeneous catalytic system for the direct synthesis of acetic acid from methane, CO and O2 are introduced to oxidize CH4 to acetic acid. From an economic perspective, if the oxidant can be replaced with CO2, the cost can be further reduced.

[0007] CO2 is a greenhouse gas, widely distributed and inexpensive. Synthesizing acetic acid from CO2 and abundant CH4 holds promise for reducing acetic acid production costs and mitigating environmental problems caused by greenhouse gases. The direct conversion of CH4 and CO2 into acetic acid is a 100% atom-economic reaction, and its industrialization could generate significant economic benefits. However, due to its thermodynamically unfavorable nature, the key to its industrialization lies in mastering methods to circumvent these thermodynamic limitations. CN111672543A discloses a method for the one-step conversion of CH4 and CO2 into acetic acid using low-temperature plasma and a modified molecular sieve catalyst, achieving an acetic acid yield of up to 55%. However, plasma catalysis is more prone to byproduct formation and suffers from low energy efficiency. Common catalytic pathways to overcome the thermodynamic limitations of the reaction include photocatalysis, electrocatalysis, and plasma catalysis, but none have yet achieved high acetic acid yields. Furthermore, these methods require additional energy and suffer from low energy efficiency and difficulty in controlling product selectivity. Therefore, there is an urgent need to develop a method for the direct conversion of CO2 and CH4 into acetic acid at low temperatures via a thermocatalytic pathway. Summary of the Invention

[0008] The main objective of this invention is to address the insufficient hydrogen source in CO2 utilization, overcome the shortcomings of existing acetic acid synthesis technologies, and provide a catalyst for the direct synthesis of acetic acid and ethanol from CO2 via a non-hydrogenation route, along with its preparation method and applications.

[0009] The present invention is achieved through the following technical solution: a catalyst for the direct synthesis of acetic acid and ethanol from CO2 via a non-hydrogenation route, wherein the catalyst support is TiO2 nanotubes, the active component is a single metal Co or a single metal Pd, or the active component is composed of a bimetallic combination of Co and Pd, and the loading of the active component is 3 wt.% to 7 wt.%.

[0010] A method for preparing the catalyst as described above includes the following steps:

[0011] S1. Preparation of TiO2 nanotubes supported by a carrier:

[0012] S1-1. Pre-calcine titanium dioxide nanoparticles (P25) at a temperature of 600℃~800℃ for 1h~5h, and then take 1g~5g of the pre-calcineed titanium dioxide nanoparticles and disperse them in a NaOH aqueous solution with a concentration of 8mol / L~12mol / L.

[0013] S1-2. After stirring the mixture prepared in step S1-1, transfer it to a hydrothermal reactor and seal it. Perform a hydrothermal reaction at a temperature of 100℃~200℃ for 24~36h to obtain the hydrothermal reactant.

[0014] S1-3. First, transfer the hydrothermal reactants prepared in step S1-2 from the hydrothermal reactor to a centrifuge tube. Start the centrifuge and centrifuge the hydrothermal reactants for 3-5 minutes. After separation, take the white precipitate. Second, wash the white precipitate with hydrochloric acid with a concentration of 0.01 mol / L to 0.1 mol / L until the pH value is 1-2. Then wash the white precipitate with deionized water until it is neutral. Third, dry the white precipitate with the pH value neutral at a temperature of 50℃ to 120℃ for 10-24 hours. Finally, calcine the dried white precipitate at a temperature of 300℃ to 400℃ for 2-5 hours to obtain TiO2 nanotubes (TNTs).

[0015] S2. Prepare catalysts in any of the following forms using the TiO2 nanotubes obtained in step S1:

[0016] 1) Single metal catalyst: The TiO2 nanotubes prepared in step S1 are dispersed in an aqueous solution containing cobalt salt or palladium salt and stirred for 12h to 24h, ultrasonically treated for 0.5h to 1h, dried at 80℃ to 120℃ for 1h to 5h, and finally calcined in air at 300℃ to 400℃ for 2h to 5h to obtain Co / TNTs or Pd / TNTs single metal catalyst;

[0017] 2) Bimetallic catalysts:

[0018] First, the TiO2 nanotubes prepared in step S1 were dispersed in an aqueous solution containing cobalt salt and stirred for 12-24 hours, ultrasonicated for 0.5-1 hour, dried at 80-120°C for 1-5 hours, and calcined in air at 300-400°C for 2-5 hours. Then, the calcined powder was dispersed in an aqueous solution containing palladium salt, and the above stirring-ultrasonic treatment-drying-calcination steps were repeated to obtain the Co-Pd / TNTs bimetallic catalyst.

[0019] 3) Alloy catalyst: The TiO2 nanotubes, cobalt salt, palladium salt and 4 mL to 6 mL of C2H5OH prepared in step S1 are mixed and ground into a dry powder mixture. The dry powder mixture is then calcined in an inert atmosphere at 300℃ to 400℃ for 3 to 5 hours to obtain the alloy catalyst.

[0020] Further, in step S2, the cobalt salt is Co(NO3)3·6H2O or Co(acac)3, and the palladium salt is Pd(NO3)2·2H2O, PdCl2 or Pd(acac)2; the inert atmosphere is N2, Ar or He atmosphere.

[0021] The application of the catalyst as described in claim 1 in the direct synthesis of acetic acid and ethanol via a non-hydrogenation route from CO2. The direct synthesis of acetic acid and ethanol via a non-hydrogenation route from CO2 includes the following steps:

[0022] First, CH4 and CO2 are used as feed gases. The feed gases are mixed with H2 and H2O respectively to form CH4+H2+H2O and CO2+H2+H2O respectively.

[0023] Then, the catalyst was added to a dual-channel fixed-bed step-by-step continuous reactor, and CH4+H2+H2O and CO2+H2+H2O were alternately fed into the two reaction channels of the dual-channel fixed-bed step-by-step continuous reactor for an alternation time of 60-300 s. The reaction temperature was 100-600 °C, and the reaction pressure was atmospheric pressure to 20 MPa. CO2 was directly synthesized into acetic acid and ethanol via a non-hydrogenation route.

[0024] Furthermore, in the CH4+H2+H2O mixed gas, the flow rate of CH4 is 1–10 mL·min. -1 The flow rate of CH4 mixed with H2 is 1–5 mL / min. -1 The flow rate of CH4 mixed with H2O was 0.001–0.05 mL·min. -1 .

[0025] In the CO2+H2+H2O mixed gas, the flow rate of CO2 is 2-10 mL·min. -1 The flow rate of CO2 mixed with H2 is 1–5 mL / min. -1The flow rate of CO2 mixed with H2O was 0.001–0.05 mL / min. -1 .

[0026] The beneficial effects of this invention are as follows:

[0027] 1. CH4 is widely distributed, inexpensive and readily available. Using it as a hydrogen-rich feedstock gas to directly synthesize ethanol and acetic acid with CO2 helps solve the problem of immature hydrogen sources in the large-scale utilization of CO2, and at the same time solves the environmental problems caused by the two greenhouse gases CO2 and CH4. It is the most economical atom utilization route (CO2+CH4→CH3COOH).

[0028] 2. Compared with the commercial methanol carbonylation method, the process of this invention is shorter and does not require the energy-intensive synthesis gas production step or the purification steps of methanol and synthesis gas; in addition, since the chemical bonds of the raw material gas CH4 and CO2 are preserved, the energy consumption of the reaction process is lower.

[0029] 3. This reaction system does not require the use of highly corrosive and toxic iodine accelerators, making this invention more environmentally friendly and simplifying the separation of catalyst and product.

[0030] 4. The reaction products of this invention are simple, and subsequent separation is even simpler. Attached Figure Description

[0031] Figure 1 TEM image of the CoPd / TNTs alloy catalyst prepared in Example 10; Figure 1 middle, Figure 1 a) The scale bar is 50 nm. Figure 1 b) has a scale of 10 nm. Figure 1 c) The scale bar is 5 nm;

[0032] Figure 2 HRTEM image of the CoPd / TNTs alloy catalyst prepared in Example 10, scale bar is 100 nm;

[0033] Figure 3 The EDS elemental mapping spectrum of the CoPd / TNTs alloy catalyst prepared in Example 10; Figure 3 middle, Figure 3 a) is the mapping spectrum of element O. Figure 3 b) is the Ti element mapping spectrum. Figure 3 c) is the Co element mapping spectrum. Figure 3 d) is the Pd element mapping spectrum;

[0034] Figure 4 The image shows the EDS spectrum of the CoPd / TNTs alloy catalyst prepared in Example 10. Detailed Implementation

[0035] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0036] Example 1

[0037] A method for preparing a catalyst for the direct synthesis of acetic acid and ethanol via a non-hydrogenation route from CO2 includes the following steps:

[0038] S1. Preparation of TiO2 nanotubes supported by a carrier:

[0039] S1-1. Pre-calcining titanium dioxide nanoparticles (P25) at 700℃ for 1h, and then dispersing 4g of the pre-calcined titanium dioxide nanoparticles in a 10mol / L NaOH aqueous solution.

[0040] S1-2. After stirring the mixture prepared in step S1-1, transfer it to a hydrothermal reactor and seal it. Then, perform a hydrothermal reaction at 120°C for 24 hours to obtain the hydrothermal reactant.

[0041] S1-3. First, transfer the hydrothermal reactants prepared in step S1-2 from the hydrothermal reactor to a centrifuge tube. Start the centrifuge and centrifuge the hydrothermal reactants for 3 minutes to separate the alkaline solution from the white precipitate. Take the white precipitate after separation. Second, wash the white precipitate with 0.1 mol / L hydrochloric acid until the pH value is 1, and then wash the white precipitate with deionized water until neutral. Third, dry the pH-neutral white precipitate at 80℃ for 10 hours. Finally, calcine the dried white precipitate (in air atmosphere) at 400℃ for 2 hours at a heating rate of 2℃·min. -1 TiO2 nanotubes (TNTs) were prepared.

[0042] S2. Preparation of Co / TNTs single-metal catalysts using the TNTs obtained in step S1:

[0043] 2.32 g of TNTs prepared in step S1 were dispersed in an aqueous solution containing 0.86 g of cobalt salt Co(NO3)3·6H2O and stirred for 24 h. The mixture was then sonicated for 1 h, dried at 80 °C for 2 h, and finally calcined at 400 °C in air for 2 h at a heating rate of 2 °C / min. -1 A Co / TNTs single-metal catalyst was prepared, in which the loading of the active component Co was 7 wt.%.

[0044] An application of the Co / TNTs single-metal catalyst prepared in Example 1 in the direct synthesis of acetic acid and ethanol via the non-hydrogenation route of CO2 includes the following steps:

[0045] First, CH4 and CO2 are used as feed gases. The feed gases are mixed with H2 and H2O respectively to form CH4+H2+H2O and CO2+H2+H2O respectively.

[0046] Then, 0.5g of the Co / TNTs single-metal catalyst prepared in Example 1 was added to a dual-channel fixed-bed step-by-step continuous reactor. CH4+H2+H2O and CO2+H2+H2O were alternately fed into the two reaction channels of the dual-channel fixed-bed step-by-step continuous reactor, with an alternation time of 100s. The reaction gas flow rates were as follows:

[0047] In the CH4+H2+H2O mixed gas, the flow rate of CH4 is 5 mL·min. -1 The flow rate of CH4 mixed with H2 is 5 mL·min. -1 The flow rate of CH4 mixed with H2O was 0.001 mL·min. -1 ;

[0048] In the CO2+H2+H2O mixed gas, the flow rate of CO2 is 5 mL·min. -1 The flow rate of CO2 mixed with H2 is 3 mL·min. -1 The flow rate of CO2 mixed with H2O is 0.001 mL·min. -1 ;

[0049] The reaction temperature was 200℃; the reaction pressure was atmospheric pressure; CO2 was used to directly synthesize acetic acid and ethanol via a non-hydrogenation route. Catalytic reaction results: the space-time yield of C2H5OH was 1.3 mg·g. cat -1 ·h -1 The space-time yield of CH3COOH was 0.21 mg·g. cat -1 ·h -1 .

[0050] Example 2

[0051] The preparation method of the Co / TNTs single metal catalyst in Example 2 is the same as that in Example 1. The application of a Co / TNTs single metal catalyst in the direct synthesis of acetic acid and ethanol via the non-hydrogenation route of CO2 includes the following steps:

[0052] First, CH4 and CO2 are used as feed gases. The feed gases are mixed with H2 and H2O respectively to form CH4+H2+H2O and CO2+H2+H2O respectively.

[0053] Then, 0.5 g of Co / TNTs single-metal catalyst was added to a dual-channel fixed-bed step-by-step continuous reactor. CH4+H2+H2O and CO2+H2+H2O were alternately fed into the two reaction channels of the dual-channel fixed-bed step-by-step continuous reactor, with an alternation time of 100 s. The reaction gas flow rates were as follows:

[0054] In the CH4+H2+H2O mixed gas, the flow rate of CH4 is 10 mL·min. -1 The flow rate of CH4 mixed with H2 is 3 mL·min. -1 The flow rate of CH4 mixed with H2O was 0.005 mL·min. -1 ;

[0055] In the CO2+H2+H2O mixed gas, the flow rate of CO2 is 10 mL·min. -1 The flow rate of CO2 mixed with H2 is 5 mL·min. -1 The flow rate of CO2 mixed with H2O is 0.005 mL·min. -1 ;

[0056] The reaction temperature was 200℃; the reaction pressure was atmospheric pressure; CO2 was used to directly synthesize acetic acid and ethanol via a non-hydrogenation route. Catalytic reaction results: the space-time yield of C2H5OH was 0.68 mg·g. cat -1 ·h -1 The space-time yield of CH3COOH was 0.16 mg·g. cat -1 ·h -1 .

[0057] Example 3

[0058] A method for preparing a catalyst for the direct synthesis of acetic acid and ethanol via a non-hydrogenation route from CO2 includes the following steps:

[0059] S1. Preparation of TiO2 nanotubes supported by a carrier:

[0060] S1-1. Pre-calcine P25 at 600℃ for 1 hour, then take 4g of the pre-calcineed P25 and disperse it in a 10mol / L NaOH aqueous solution.

[0061] S1-2. After stirring the mixture prepared in step S1-1, transfer it to a hydrothermal reactor and seal it. Then, perform a hydrothermal reaction at 180°C for 24 hours to obtain the hydrothermal reactant.

[0062] S1-3. First, transfer the hydrothermal reactants prepared in step S1-2 from the hydrothermal reactor to a centrifuge tube. Start the centrifuge and centrifuge the hydrothermal reactants for 5 minutes to separate the alkaline solution from the white precipitate. Take the white precipitate after separation. Second, wash the white precipitate with 0.01 mol / L hydrochloric acid until the pH value is 2, and then wash the white precipitate with deionized water until neutral. Third, dry the pH-neutral white precipitate at 120℃ for 24 hours. Finally, calcine the dried white precipitate (in air atmosphere) at 400℃ for 2 hours at a heating rate of 2℃·min. -1 TNTs were produced.

[0063] S2. Preparation of Co / TNTs single-metal catalysts using the TNTs obtained in step S1:

[0064] 2.32 g of TNTs prepared in step S1 were dispersed in an aqueous solution containing 0.86 g of cobalt salt Co(NO3)3·6H2O and stirred for 12 h. The mixture was then sonicated for 0.5 h, dried at 110 °C for 2 h, and finally calcined at 400 °C in air for 2 h at a heating rate of 2 °C / min. -1 A Co / TNTs single-metal catalyst was prepared, in which the loading of the active component Co was 7 wt.%.

[0065] An application of the Co / TNTs single-metal catalyst prepared in Example 3 of this paper in the direct synthesis of acetic acid and ethanol via the non-hydrogenation route of CO2 includes the following steps:

[0066] First, CH4 and CO2 are used as feed gases. The feed gases are mixed with H2 and H2O respectively to form CH4+H2+H2O and CO2+H2+H2O respectively.

[0067] Then, 0.5g of the Co / TNTs single-metal catalyst prepared in Example 3 was added to a dual-channel fixed-bed step-by-step continuous reactor. CH4+H2+H2O and CO2+H2+H2O were alternately fed into the two reaction channels of the dual-channel fixed-bed step-by-step continuous reactor, with an alternation time of 60s. The reaction gas flow rates were as follows:

[0068] In the CH4+H2+H2O mixed gas, the flow rate of CH4 is 10 mL·min. -1 The flow rate of CH4 mixed with H2 is 5 mL·min. -1 The flow rate of CH4 mixed with H2O was 0.05 mL·min. -1 ;

[0069] In the CO2+H2+H2O mixed gas, the flow rate of CO2 is 10 mL·min.-1 The flow rate of CO2 mixed with H2 is 5 mL·min. -1 The flow rate of CO2 mixed with H2O is 0.005 mL·min. -1 ;

[0070] The reaction temperature was 150℃; the reaction pressure was atmospheric pressure; CO2 was used to directly synthesize acetic acid and ethanol via a non-hydrogenation route. Catalytic reaction results: the space-time yield of C2H5OH was 2.7 mg·g. cat -1 ·h -1 The space-time yield of CH3COOH was 0.4 mg·g. cat -1 ·h -1 .

[0071] Example 4

[0072] A method for preparing a catalyst for the direct synthesis of acetic acid and ethanol via a non-hydrogenation route from CO2 includes the following steps:

[0073] S1. Preparation of TiO2 nanotubes supported by a carrier:

[0074] S1-1. Pre-calcinate P25 at 700℃ for 2 hours, then take 4g of the pre-calcined P25 and disperse it in an 8mol / L NaOH aqueous solution.

[0075] S1-2. After stirring the mixture prepared in step S1-1, transfer it into a hydrothermal reactor and seal it. Then, perform a hydrothermal reaction at 140°C for 27 hours to obtain the hydrothermal reactant.

[0076] S1-3. First, transfer the hydrothermal reactants prepared in step S1-2 from the hydrothermal reactor to a centrifuge tube. Start the centrifuge and centrifuge the hydrothermal reactants for 4 minutes to separate the alkaline solution from the white precipitate. Take the white precipitate after separation. Second, wash the white precipitate with 0.01 mol / L hydrochloric acid until the pH value is 2, and then wash the white precipitate with deionized water until neutral. Third, dry the pH-neutral white precipitate at 100℃ for 12 hours. Finally, calcine the dried white precipitate (in air atmosphere) at 350℃ for 3 hours at a heating rate of 2℃·min. -1 TNTs were produced.

[0077] S2. Preparation of Pd / TNTs single-metal catalyst using the TNTs obtained in step S1:

[0078] 2.41 g of TNTs prepared in step S1 were dispersed in an aqueous solution containing 0.22 g of palladium salt Pd(NO3)2·2H2O and stirred for 12 h. The mixture was then sonicated for 0.5 h, dried at 100 °C for 2 h, and finally calcined at 350 °C in air for 2 h at a heating rate of 2 °C / min. -1 A Pd / TNTs single-metal catalyst was prepared, in which the loading of the active component Pd was 3.5 wt.%.

[0079] An application of the Pd / TNTs single-metal catalyst prepared in Example 4 of this paper in the direct synthesis of acetic acid and ethanol via the non-hydrogenation route of CO2 includes the following steps:

[0080] First, CH4 and CO2 are used as feed gases. The feed gases are mixed with H2 and H2O respectively to form CH4+H2+H2O and CO2+H2+H2O respectively.

[0081] Then, 0.5g of the Co / TNTs single-metal catalyst prepared in Example 4 was added to a dual-channel fixed-bed step-by-step continuous reactor. CH4+H2+H2O and CO2+H2+H2O were alternately fed into the two reaction channels of the dual-channel fixed-bed step-by-step continuous reactor, with an alternation time of 60s. The reaction gas flow rates were as follows:

[0082] In the CH4+H2+H2O mixed gas, the flow rate of CH4 is 5 mL·min. -1 The flow rate of CH4 mixed with H2 is 5 mL·min. -1 The flow rate of CH4 mixed with H2O was 0.001 mL·min. -1 ;

[0083] In the CO2+H2+H2O mixed gas, the flow rate of CO2 is 8 mL·min. -1 The flow rate of CO2 mixed with H2 is 2 mL·min. -1 The flow rate of CO2 mixed with H2O is 0.01 mL·min. -1 ;

[0084] The reaction temperature was 150℃, and the reaction pressure was 2 MPa. Acetic acid and ethanol were directly synthesized from CO2 via a non-hydrogenation route. Catalytic reaction results: the space-time yield of C2H5OH was 5.2 mg·g⁻¹. cat -1 ·h -1 The space-time yield of CH3COOH was 6.9 mg·g. cat -1 ·h -1 .

[0085] Example 5

[0086] The preparation method of the Pd / TNTs single metal catalyst in Example 5 is the same as that in Example 4. The application of a Pd / TNTs single metal catalyst in the direct synthesis of acetic acid and ethanol via the non-hydrogenation route of CO2 includes the following steps:

[0087] First, CH4 and CO2 are used as feed gases. The feed gases are mixed with H2 and H2O respectively to form CH4+H2+H2O and CO2+H2+H2O respectively.

[0088] Then, 0.5 g of Pd / TNTs single-metal catalyst was added to a dual-channel fixed-bed step-by-step continuous reactor. CH4+H2+H2O and CO2+H2+H2O were alternately fed into the two reaction channels of the dual-channel fixed-bed step-by-step continuous reactor, with an alternation time of 60 s. The reaction gas flow rates were as follows:

[0089] In the CH4+H2+H2O mixed gas, the flow rate of CH4 is 8 mL·min. -1 The flow rate of CH4 mixed with H2 is 2 mL·min. -1 The flow rate of CH4 mixed with H2O was 0.001 mL·min. -1 ;

[0090] In the CO2+H2+H2O mixed gas, the flow rate of CO2 is 10 mL·min. -1 The flow rate of CO2 mixed with H2 is 3 mL·min. -1 The flow rate of CO2 mixed with H2O is 0.005 mL·min. -1 ;

[0091] The reaction temperature was 180℃; the reaction pressure was atmospheric pressure; CO2 was used to directly synthesize acetic acid and ethanol via a non-hydrogenation route. Catalytic reaction results: the space-time yield of C2H5OH was 2.3 mg·g. cat -1 ·h -1 The space-time yield of CH3COOH was 1.9 mg·g. cat -1 ·h -1 .

[0092] Example 6

[0093] A method for preparing a catalyst for the direct synthesis of acetic acid and ethanol via a non-hydrogenation route from CO2 includes the following steps:

[0094] S1. Preparation of TiO2 nanotubes supported by a carrier:

[0095] S1-1. Pre-calcine P25 at 600℃ for 1 hour, then take 4g of the pre-calcineed P25 and disperse it in a 10mol / L NaOH aqueous solution.

[0096] S1-2. After stirring the mixture prepared in step S1-1, transfer it to a hydrothermal reactor and seal it. Then, perform a hydrothermal reaction at 180°C for 24 hours to obtain the hydrothermal reactant.

[0097] S1-3. First, transfer the hydrothermal reactants prepared in step S1-2 from the hydrothermal reactor to a centrifuge tube. Start the centrifuge and centrifuge the hydrothermal reactants for 5 minutes to separate the alkaline solution from the white precipitate. Take the white precipitate after separation. Second, wash the white precipitate with 0.01 mol / L hydrochloric acid until the pH value is 2, and then wash the white precipitate with deionized water until neutral. Third, dry the pH-neutral white precipitate at 120℃ for 24 hours. Finally, calcine the dried white precipitate (in air atmosphere) at 400℃ for 3 hours at a heating rate of 2℃·min. -1 TNTs were produced.

[0098] S2. Preparation of Pd / TNTs single-metal catalyst using the TNTs obtained in step S1:

[0099] 2.41 g of TNTs prepared in step S1 were dispersed in an aqueous solution containing 0.22 g of palladium salt Pd(NO3)2·2H2O and stirred for 12 h. The mixture was then sonicated for 0.5 h, dried at 110 °C for 2 h, and finally calcined at 400 °C in air for 2 h at a heating rate of 2 °C / min. -1 A Pd / TNTs single-metal catalyst was prepared, in which the loading of the active component Pd was 3.5 wt.%.

[0100] An application of the Pd / TNTs single-metal catalyst prepared in Example 6 of this paper in the direct synthesis of acetic acid and ethanol via the non-hydrogenation route of CO2 includes the following steps:

[0101] First, CH4 and CO2 are used as feed gases. The feed gases are mixed with H2 and H2O respectively to form CH4+H2+H2O and CO2+H2+H2O respectively.

[0102] Then, 0.5g of the Co / TNTs single-metal catalyst prepared in Example 6 was added to a dual-channel fixed-bed step-by-step continuous reactor. CH4+H2+H2O and CO2+H2+H2O were alternately fed into the two reaction channels of the dual-channel fixed-bed step-by-step continuous reactor, with an alternation time of 60s. The reaction gas flow rates were as follows:

[0103] In the CH4+H2+H2O mixed gas, the flow rate of CH4 is 9 mL·min. -1 The flow rate of CH4 mixed with H2 is 3 mL·min.-1 The flow rate of CH4 mixed with H2O was 0.04 mL·min. -1 ;

[0104] In the CO2+H2+H2O mixed gas, the flow rate of CO2 is 9 mL·min. -1 The flow rate of CO2 mixed with H2 is 2 mL·min. -1 The flow rate of CO2 mixed with H2O is 0.01 mL·min. -1 ;

[0105] The reaction temperature was 150℃; the reaction pressure was atmospheric pressure; CO2 was used to directly synthesize acetic acid and ethanol via a non-hydrogenation route. Catalytic reaction results: the space-time yield of C2H5OH was 1.6 mg·g. cat -1 ·h -1 The space-time yield of CH3COOH was 2.8 mg·g. cat -1 ·h -1 .

[0106] Example 7

[0107] A method for preparing a catalyst for the direct synthesis of acetic acid and ethanol via a non-hydrogenation route from CO2 includes the following steps:

[0108] S1. Preparation of TiO2 nanotubes supported by a carrier:

[0109] S1-1. Pre-calcining P25 at 650℃ for 3 hours, then dispersing 4g of the pre-calcined P25 in a 12mol / L NaOH aqueous solution.

[0110] S1-2. After stirring the mixture prepared in step S1-1, transfer it to a hydrothermal reactor and seal it. Then, perform a hydrothermal reaction at 180°C for 24 hours to obtain the hydrothermal reactant.

[0111] S1-3. First, transfer the hydrothermal reactants prepared in step S1-2 from the hydrothermal reactor to a centrifuge tube. Start the centrifuge and centrifuge the hydrothermal reactants for 5 minutes to separate the alkaline solution from the white precipitate. Take the white precipitate after separation. Second, wash the white precipitate with 0.08 mol / L hydrochloric acid until the pH value is 2, and then wash the white precipitate with deionized water until neutral. Third, dry the pH-neutral white precipitate at 110℃ for 12 hours. Finally, calcine the dried white precipitate (in air atmosphere) at 400℃ for 3 hours at a heating rate of 2℃·min. -1 TNTs were produced.

[0112] S2. Prepare Co-Pd / TNTs bimetallic catalysts using the TNTs obtained in step S1:

[0113] 2.24 g of TNTs prepared in step S1 were dispersed in an aqueous solution of Co(NO3)3·6H2O containing 0.86 g of cobalt salt and stirred for 14 h. The mixture was then sonicated for 0.8 h, dried at 120 °C for 1 h, and finally calcined at 350 °C in air for 5 h at a heating rate of 2 °C / min. -1 ;

[0114] The calcined powder was dispersed in an aqueous solution containing 0.22 g of cobalt salt Pd(NO3)2·2H2O and stirred for 24 h, ultrasonicated for 1 h, dried at 90 °C for 3 h, and finally calcined at 400 °C in air for 3 h at a heating rate of 2 °C·min. -1 A Co-Pd / TNTs bimetallic catalyst was prepared, with the following loadings of active components: Co: 7 wt.% and Pd: 3.5 wt.%.

[0115] An application of the Co-Pd / TNTs bimetallic catalyst prepared in Example 7 of this paper in the direct synthesis of acetic acid and ethanol via the non-hydrogenation route of CO2 includes the following steps:

[0116] First, CH4 and CO2 are used as feed gases. The feed gases are mixed with H2 and H2O respectively to form CH4+H2+H2O and CO2+H2+H2O respectively.

[0117] Then, 0.5g of the Co-Pd / TNTs bimetallic catalyst prepared in Example 7 was added to a dual-channel fixed-bed step-by-step continuous reactor. CH4+H2+H2O and CO2+H2+H2O were alternately fed into the two reaction channels of the dual-channel fixed-bed step-by-step continuous reactor, with an alternation time of 200s. The reaction gas flow rates were as follows:

[0118] In the CH4+H2+H2O mixed gas, the flow rate of CH4 is 5 mL·min. -1 The flow rate of CH4 mixed with H2 is 3 mL·min. -1 The flow rate of CH4 mixed with H2O was 0.001 mL·min. -1 ;

[0119] In the CO2+H2+H2O mixed gas, the flow rate of CO2 is 5 mL·min. -1 The flow rate of CO2 mixed with H2 is 3 mL·min. -1 The flow rate of CO2 mixed with H2O was 0.03 mL·min. -1 ;

[0120] The reaction temperature was 300℃, and the reaction pressure was 3 MPa. Acetic acid and ethanol were directly synthesized from CO2 via a non-hydrogenation route. Catalytic reaction results: the space-time yield of C2H5OH was 10.2 mg·g⁻¹. cat -1 ·h -1 The space-time yield of CH3COOH was 20.5 mg·g. cat -1 ·h -1 .

[0121] Example 8

[0122] The preparation method of the Co-Pd / TNTs bimetallic catalyst in Example 8 is the same as that in Example 7. The application of a Co-Pd / TNTs bimetallic catalyst in the direct synthesis of acetic acid and ethanol via the non-hydrogenation route of CO2 includes the following steps:

[0123] First, CH4 and CO2 are used as feed gases. The feed gases are mixed with H2 and H2O respectively to form CH4+H2+H2O and CO2+H2+H2O respectively.

[0124] Then, 0.5 g of Co-Pd / TNTs bimetallic catalyst was added to a dual-channel fixed-bed step-by-step continuous reactor. CH4+H2+H2O and CO2+H2+H2O were alternately fed into the two reaction channels of the dual-channel fixed-bed step-by-step continuous reactor, with an alternation time of 200 s. The reaction gas flow rates were as follows:

[0125] In the CH4+H2+H2O mixed gas, the flow rate of CH4 is 7 mL·min. -1 The flow rate of CH4 mixed with H2 is 5 mL·min. -1 The flow rate of CH4 mixed with H2O was 0.02 mL·min. -1 ;

[0126] In the CO2+H2+H2O mixed gas, the flow rate of CO2 is 7 mL·min. -1 The flow rate of CO2 mixed with H2 is 5 mL·min. -1 The flow rate of CO2 mixed with H2O was 0.003 mL·min. -1 ;

[0127] The reaction temperature was 250℃, and the reaction pressure was 2 MPa. Acetic acid and ethanol were directly synthesized from CO2 via a non-hydrogenation route. Catalytic reaction results: the space-time yield of C2H5OH was 8.1 mg·g⁻¹. cat -1 ·h -1 The space-time yield of CH3COOH was 18.7 mg·g. cat -1 ·h-1 .

[0128] Example 9

[0129] The preparation method of the Co-Pd / TNTs bimetallic catalyst in Example 9 is the same as that in Example 7. The application of a Co-Pd / TNTs bimetallic catalyst in the direct synthesis of acetic acid and ethanol via the non-hydrogenation route of CO2 includes the following steps:

[0130] First, CH4 and CO2 are used as feed gases. The feed gases are mixed with H2 and H2O respectively to form CH4+H2+H2O and CO2+H2+H2O respectively.

[0131] Then, 0.5 g of Co-Pd / TNTs bimetallic catalyst was added to a dual-channel fixed-bed step-by-step continuous reactor. CH4+H2+H2O and CO2+H2+H2O were alternately fed into the two reaction channels of the dual-channel fixed-bed step-by-step continuous reactor, with an alternation time of 200 s. The reaction gas flow rates were as follows:

[0132] In the CH4+H2+H2O mixed gas, the flow rate of CH4 is 8 mL·min. -1 The flow rate of CH4 mixed with H2 is 3 mL·min. -1 The flow rate of CH4 mixed with H2O was 0.02 mL·min. -1 ;

[0133] In the CO2+H2+H2O mixed gas, the flow rate of CO2 is 8 mL·min. -1 The flow rate of CO2 mixed with H2 is 3 mL·min. -1 The flow rate of CO2 mixed with H2O is 0.02 mL·min. -1 ;

[0134] The reaction temperature was 150℃, and the reaction pressure was 2 MPa. Acetic acid and ethanol were directly synthesized from CO2 via a non-hydrogenation route. Catalytic reaction results: the space-time yield of C2H5OH was 11.3 mg·g⁻¹. cat -1 ·h -1 The space-time yield of CH3COOH was 24.5 mg·g. cat -1 ·h -1 .

[0135] Example 10

[0136] A method for preparing a catalyst for the direct synthesis of acetic acid and ethanol via a non-hydrogenation route from CO2 includes the following steps:

[0137] S1. Preparation of TiO2 nanotubes supported by a carrier:

[0138] S1-1. Pre-calcine P25 at 700℃ for 2 hours, then take 4g of the pre-calcineed P25 and disperse it in a 10mol / L NaOH aqueous solution.

[0139] S1-2. After stirring the mixture prepared in step S1-1, transfer it to a hydrothermal reactor and seal it. Then, perform a hydrothermal reaction at 120°C for 24 hours to obtain the hydrothermal reactant.

[0140] S1-3. First, transfer the hydrothermal reactants prepared in step S1-2 from the hydrothermal reactor to a centrifuge tube. Start the centrifuge and centrifuge the hydrothermal reactants for 3 minutes to separate the alkaline solution from the white precipitate. Take the white precipitate after separation. Second, wash the white precipitate with 0.01 mol / L hydrochloric acid until the pH value is 2, and then wash the white precipitate with deionized water until neutral. Third, dry the pH-neutral white precipitate at 110℃ for 24 hours. Finally, calcine the dried white precipitate (in air atmosphere) at 400℃ for 4 hours at a heating rate of 2℃·min. -1 TNTs were produced.

[0141] S2. Prepare alloy catalysts using the TNTs obtained in step S1:

[0142] 2.24 g of TNTs prepared in step S1, 1.07 g of cobalt salt Co(acac)3, 0.25 g of palladium salt Pd(acac)2, and 6 mL of L2H5OH were mixed and ground into a dry powder mixture. The dry powder mixture was then transferred to a ceramic boat and calcined at 400 °C under an inert N2 atmosphere for 5 h to obtain a CoPd / TNTs alloy catalyst. The loading of the active components in the CoPd / TNTs alloy catalyst was: Co: 7 wt.% and Pd: 3.5 wt.%.

[0143] The morphology of the catalyst was preliminarily characterized by transmission electron microscopy (TEM). The morphology of the CoPd / TNTs alloy catalyst prepared in Example 10 is as follows: Figure 1 As shown, from Figure 1 As can be seen, TNTs are multilayer nanotubes with an interlayer spacing of 0.74 nm; Figure 1 a) and Figure 1 b) shows metal nanoparticles uniformly distributed on a TNT support, derived from... Figure 1 c) It can be seen that the lattice spacing of the Co-Pd alloy is 0.220 nm, which is between the lattice spacing of the Co(111) crystal plane (0.197 nm) and the lattice spacing of the Pd(111) crystal plane (0.225 nm), indicating that the Co-Pd alloy is formed during pyrolysis. Energy dispersive X-ray spectroscopy (EDS) analysis was used to detect... Figure 2The distribution of O, Ti, Pd, and Co elements in TNTs in the region shown is as follows: Figure 3 As shown in a)-3d), O, Ti, Pd, and Co elements are uniformly distributed on the TNTs support. Figure 4 The EDS spectrum of the CoPd / TNTs alloy catalyst shows that the main elements on the CoPd / TNTs catalyst are O, Ti, Co, and Pd, as well as untreated H. + The Na element remaining after complete exchange.

[0144] An application of the CoPd / TNTs alloy catalyst prepared in Example 10 in the direct synthesis of acetic acid and ethanol via the non-hydrogenation route of CO2 includes the following steps:

[0145] First, CH4 and CO2 are used as feed gases. The feed gases are mixed with H2 and H2O respectively to form CH4+H2+H2O and CO2+H2+H2O respectively.

[0146] Then, 0.5g of the CoPd / TNTs alloy catalyst prepared in Example 10 was added to a dual-channel fixed-bed step-by-step continuous reactor. CH4+H2+H2O and CO2+H2+H2O were alternately fed into the two reaction channels of the dual-channel fixed-bed step-by-step continuous reactor, with an alternation time of 300s. The reaction gas flow rates were as follows:

[0147] In the CH4+H2+H2O mixed gas, the flow rate of CH4 is 5 mL·min. -1 The flow rate of CH4 mixed with H2 is 2 mL·min. -1 The flow rate of CH4 mixed with H2O was 0.001 mL·min. -1 ;

[0148] In the CO2+H2+H2O mixed gas, the flow rate of CO2 is 5 mL·min. -1 The flow rate of CO2 mixed with H2 is 2 mL·min. -1 The flow rate of CO2 mixed with H2O is 0.001 mL·min. -1 ;

[0149] The reaction temperature was 150℃, and the reaction pressure was 3 MPa. Acetic acid and ethanol were directly synthesized from CO2 via a non-hydrogenation route. Catalytic reaction results: the space-time yield of C2H5OH was 11.3 mg·g⁻¹. cat -1 ·h -1 The space-time yield of CH3COOH was 35.1 mg·g. cat -1 ·h -1 .

[0150] Example 11

[0151] The preparation method of the CoPd / TNTs alloy catalyst in Example 11 is the same as that in Example 10. The application of a CoPd / TNTs alloy catalyst in the direct synthesis of acetic acid and ethanol via the non-hydrogenation route of CO2 includes the following steps:

[0152] First, CH4 and CO2 are used as feed gases. The feed gases are mixed with H2 and H2O respectively to form CH4+H2+H2O and CO2+H2+H2O respectively.

[0153] Then, 0.5 g of CoPd / TNTs alloy catalyst was added to a dual-channel fixed-bed step-by-step continuous reactor. CH4+H2+H2O and CO2+H2+H2O were alternately fed into the two reaction channels of the dual-channel fixed-bed step-by-step continuous reactor, with an alternation time of 300 s. The reaction gas flow rates were as follows:

[0154] In the CH4+H2+H2O mixed gas, the flow rate of CH4 is 10 mL·min. -1 The flow rate of CH4 mixed with H2 is 2 mL·min. -1 The flow rate of CH4 mixed with H2O was 0.001 mL·min. -1 ;

[0155] In the CO2+H2+H2O mixed gas, the flow rate of CO2 is 10 mL·min. -1 The flow rate of CO2 mixed with H2 is 5 mL·min. -1 The flow rate of CO2 mixed with H2O is 0.05 mL·min. -1 ;

[0156] The reaction temperature was 250℃, and the reaction pressure was 2 MPa. Acetic acid and ethanol were directly synthesized from CO2 via a non-hydrogenation route. Catalytic reaction results: the space-time yield of C2H5OH was 8.1 mg·g⁻¹. cat -1 ·h -1 The space-time yield of CH3COOH was 18.7 mg·g. cat -1 ·h -1 .

[0157] Example 12

[0158] The preparation method of the CoPd / TNTs alloy catalyst in Example 12 is the same as that in Example 10. The application of a CoPd / TNTs alloy catalyst in the direct synthesis of acetic acid and ethanol via the non-hydrogenation route of CO2 includes the following steps:

[0159] First, CH4 and CO2 are used as feed gases. The feed gases are mixed with H2 and H2O respectively to form CH4+H2+H2O and CO2+H2+H2O respectively.

[0160] Then, 0.5 g of CoPd / TNTs alloy catalyst was added to a dual-channel fixed-bed step-by-step continuous reactor. CH4+H2+H2O and CO2+H2+H2O were alternately fed into the two reaction channels of the dual-channel fixed-bed step-by-step continuous reactor, with an alternation time of 300 s. The reaction gas flow rates were as follows:

[0161] In the CH4+H2+H2O mixed gas, the flow rate of CH4 is 6 mL·min. -1 The flow rate of CH4 mixed with H2 is 2 mL·min. -1 The flow rate of CH4 mixed with H2O was 0.01 mL·min. -1 ;

[0162] In the CO2+H2+H2O mixed gas, the flow rate of CO2 is 6 mL·min. -1 The flow rate of CO2 mixed with H2 is 2 mL·min. -1 The flow rate of CO2 mixed with H2O is 0.001 mL·min. -1 ;

[0163] The reaction temperature was 300℃; the reaction pressure was 2 MPa, and CO2 was directly synthesized into acetic acid and ethanol via a non-hydrogenation route. Catalytic reaction results: the space-time yield of C2H5OH was 6.2 mg·g⁻¹. cat -1 ·h -1 The space-time yield of CH3COOH was 10.4 mg·g. cat -1 ·h -1 .

[0164] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A catalyst for the direct synthesis of acetic acid and ethanol via a non-hydrogenation route from CO2, characterized in that: The catalyst support is TiO2 nanotubes, and the active component is composed of CoPd alloy, with a loading of 3 wt.% to 7 wt.% of the active component. The method for preparing the catalyst includes the following steps: S1. Preparation of TiO2 nanotubes on support: S1-1. Pre-calcine titanium dioxide nanoparticles at a temperature of 600℃~800℃ for 1h~5h, and then take 1g~5g of the pre-calcineed titanium dioxide nanoparticles and disperse them in a NaOH aqueous solution with a concentration of 8mol / L~12mol / L. S1-2. After stirring the mixture prepared in step S1-1, transfer it to a hydrothermal reactor and seal it. Perform a hydrothermal reaction at a temperature of 100℃~200℃ for 24~36 hours to obtain the hydrothermal reactant. S1-3. First, transfer the hydrothermal reactants prepared in step S1-2 from the hydrothermal reactor to a centrifuge tube. Start the centrifuge and centrifuge the hydrothermal reactants for 3-5 minutes. After separation, take the white precipitate. Second, wash the white precipitate with hydrochloric acid with a concentration of 0.01 mol / L to 0.1 mol / L until the pH value is 1-2. Then wash the white precipitate with deionized water until it is neutral. Third, dry the pH-neutral white precipitate at a temperature of 50℃ to 120℃ for 10-24 hours. Finally, calcine the dried white precipitate at a temperature of 300℃ to 400℃ for 2-5 hours to obtain TiO2 nanotubes. S2. Preparation of alloy catalysts using TiO2 nanotubes obtained in step S1: The TiO2 nanotubes, cobalt salt, palladium salt, and 4 mL to 6 mL of C2H5OH prepared in step S1 were mixed and ground into a dry powder mixture. The dry powder mixture was then calcined in an inert atmosphere at a temperature of 300℃ to 400℃ for 3 to 5 hours to obtain the alloy catalyst.

2. A method for preparing the catalyst as described in claim 1, characterized in that, Includes the following steps: S1. Preparation of TiO2 nanotubes on support: S1-1. Pre-calcine titanium dioxide nanoparticles at a temperature of 600℃~800℃ for 1h~5h, and then take 1g~5g of the pre-calcineed titanium dioxide nanoparticles and disperse them in a NaOH aqueous solution with a concentration of 8mol / L~12mol / L. S1-2. After stirring the mixture prepared in step S1-1, transfer it to a hydrothermal reactor and seal it. Perform a hydrothermal reaction at a temperature of 100℃~200℃ for 24~36 hours to obtain the hydrothermal reactant. S1-3. First, transfer the hydrothermal reactants prepared in step S1-2 from the hydrothermal reactor to a centrifuge tube, start the centrifuge and centrifuge the hydrothermal reactants for 3 min to 5 min, and take the white precipitate after separation. Next, the white precipitate was washed with hydrochloric acid at a concentration of 0.01 mol / L to 0.1 mol / L until the pH value was 1 to 2, and then washed with deionized water until neutral. Next, the white precipitate with the pH value neutral was dried at a temperature of 50℃ to 120℃ for 10 h to 24 h. Finally, the dried white precipitate was calcined at a temperature of 300℃ to 400℃ for 2 h to 5 h to obtain TiO2 nanotubes. S2. Preparation of alloy catalysts using TiO2 nanotubes obtained in step S1: The TiO2 nanotubes, cobalt salt, palladium salt, and 4 mL to 6 mL of C2H5OH prepared in step S1 were mixed and ground into a dry powder mixture. The dry powder mixture was then calcined in an inert atmosphere at a temperature of 300℃ to 400℃ for 3 to 5 hours to obtain the alloy catalyst.

3. The preparation method according to claim 2, characterized in that: In step S2, the cobalt salt is Co(acac)3 and the palladium salt is Pd(acac)2; the inert atmosphere is N2, Ar or He atmosphere.

4. The application of the catalyst as described in claim 1 in the direct synthesis of acetic acid and ethanol via a non-hydrogenation route from CO2.

5. The application according to claim 4, characterized in that: The direct synthesis of acetic acid and ethanol via the non-hydrogenation route using CO2 includes the following steps: First, CH4 and CO2 are used as feed gases. The feed gases are mixed with H2 and H2O respectively to form CH4+H2+H2O and CO2+H2+H2O respectively. Then, the catalyst is added to a dual-channel fixed-bed step-by-step continuous reactor, and CH4+H2+H2O and CO2+H2+H2O are alternately fed into the two reaction channels of the dual-channel fixed-bed step-by-step continuous reactor for an alternation time of 60~300s. The reaction temperature is 100~600℃, and the reaction pressure is atmospheric pressure to 20MPa. CO2 is directly synthesized into acetic acid and ethanol via a non-hydrogenation route.

6. The application according to claim 5, characterized in that: In the CH4+H2+H2O mixed gas, the flow rate of CH4 is 1~10 mL·min. -1 The flow rate of CH4 mixed with H2 is 1~5 mL·min. -1 The flow rate of CH4 mixed with H2O was 0.001~0.05 mL·min. -1 ; In the CO2+H2+H2O mixed gas, the flow rate of CO2 is 2~10 mL·min. -1 The flow rate of CO2 mixed with H2 is 1~5 mL·min. -1 The flow rate of CO2 mixed with H2O is 0.001~0.05 mL·min. -1 .

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