A method for preparing a cobalt-molybdenum catalyst and its application in the hydrogenation of CO2 / H2S to produce methanethiol.

Abstract

This invention discloses a method for preparing a cobalt-molybdenum catalyst and its application in the hydrogenation of CO2 / H2S to methanethiol. The method uses a titanium source as a modifying additive and ethanol as a structure-directing agent to synthesize a plate-like hydrotalcite-like precursor via a simple hydrothermal method. Based on this precursor, an active component is further loaded to obtain a highly dispersed, vacancy-rich cobalt-molybdenum catalyst. The addition of the titanium source increases the electron cloud density around the active component, and the transferred electrons reduce the strength of Mo-S and Co-S bonds, making them more prone to breakage and forming sulfur defects, thus promoting the adsorption and activation of CO2 and H2S. Simultaneously, due to the injection of additional charge, MoS2 is induced to undergo a phase transition from the 2H phase to the 1T phase, improving its catalytic hydrogenation capacity during the reaction. Ultimately, the cobalt-molybdenum catalyst exhibits considerable catalytic activity in the CO2 / H2S hydrogenation to methanethiol reaction system.

Description

Technical Field

[0001] This invention relates to a preparation technique for an environmental catalyst and its application, specifically to the preparation of a cobalt-molybdenum catalyst and its application in the hydrogenation of CO2 / H2S to produce methanethiol. Background Technology

[0002] The steel industry generates a large number of byproducts and emissions during production, such as blast furnace gas, which contains large amounts of hydrogen sulfide (H2S) and carbon dioxide (CO2). How to effectively control H2S pollution and reduce CO2 emissions has become an urgent problem to be solved.

[0003] While H2S and CO2 are polluting gases, they can also be used as raw materials for chemical production. Among various sulfur-containing compounds, methanethiol, as a key fine chemical raw material and organic synthesis intermediate, plays an important role in the synthesis of pesticides, pharmaceuticals, and food, especially in the production of the feed additive methionine, where it has wide applications and high economic benefits (market price approximately 30,000 RMB / ton). The method of directly synthesizing methanethiol using H2S and CO2 as raw materials not only removes harmful H2S and CO2 but also yields the high-value-added product methanethiol, achieving efficient resource utilization. The key to this goal lies in the catalyst.

[0004] Based on this, the present invention discloses a method for preparing a cobalt-molybdenum catalyst and its application in the hydrogenation of CO2 / H2S to produce methanethiol. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for preparing a cobalt-molybdenum catalyst and its application, thus solving problems such as low conversion rates in existing catalysts for the hydrogenation of CO2 / H2S to methanethiol. This invention uses titanium-modified layered double hydroxide (TLH) as a precursor, utilizing the flexible variability of its cation valence state to transfer electrons to the active component, increasing the electron density around it, reducing the strength of Mo-S and Co-S bonds, promoting high dispersion of the active component, and generating abundant sulfur defects, thereby effectively improving the reactivity of the hydrogenation of H2S and CO2 to methanethiol. The catalyst's plate-like morphology promotes full exposure of active sites, facilitating sufficient contact between the active sites and reactants. Sulfur vacancies further promote the adsorption and activation of CO2 and H2S.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] A method for preparing a cobalt-molybdenum catalyst includes the following steps:

[0008] (1) Measure 50~500 μL of titanium source and dissolve it in 30 mL of anhydrous ethanol, and stir continuously for half an hour;

[0009] (2) Dissolve 1-5 mmol of cobalt source, 1-5 mmol of aluminum source and 10-30 mmol of precipitant in 60 mL of deionized water in sequence;

[0010] (3) After mixing the solutions obtained in steps (1) and (2), stir continuously for half an hour;

[0011] (4) Pour the mixed solution obtained in step (3) into a hydrothermal reactor and react at 120~150 °C;

[0012] (5) After the temperature of the hydrothermal reactor drops to room temperature, the obtained precipitate is filtered, washed and placed in an oven to dry, thus obtaining the modified ternary hydrotalcite precursor CoAlTi-LDH;

[0013] (6) The precursor obtained in step (5) is calcined at a certain temperature to obtain the ternary oxide CoAlTi-LDO;

[0014] (7) Soluble molybdenum salt and potassium carbonate are impregnated on the ternary oxide by equal volume impregnation method, and the cobalt-molybdenum catalyst is obtained by calcination and sulfidation.

[0015] Preferably, the titanium source in step (1) is titanium tetrachloride (TiCl4) or tetraisopropyl titanate (C). 12 H 28 O4Ti).

[0016] Preferably, the cobalt source in step (2) is Co(NO3)2·6H2O or CoCl2·6H2O, the aluminum source is Al(NO3)3·9H2O or AlCl3·9H2O, and the precipitant is urea.

[0017] Preferably, the reaction time in step (4) is 10 to 20 hours, and more preferably 12 hours.

[0018] Preferably, the filtration and washing in step (5) are performed by alternating between distilled water and anhydrous ethanol three times each.

[0019] Preferably, the drying temperature in step (5) is 80~100 ℃.

[0020] Preferably, the roasting temperature in step (6) is 400~500 ℃, more preferably 450 ℃, and the roasting time is 2~5 h, more preferably 4 h.

[0021] Preferably, the soluble molybdenum salt in step (7) is ammonium heptamolybdate or ammonium tetramolybdate.

[0022] Preferably, the roasting temperature in step (7) is 400~500 ℃, more preferably 400 ℃, and the roasting time is 2~5 h, more preferably 2 h.

[0023] Preferably, in step (7), the sulfidation gas is 10% H2S / H2, the sulfidation temperature is 400 ℃, and the sulfidation time is 8h.

[0024] Preferably, the final product, the cobalt-molybdenum catalyst, is composed of 40-60 mesh particles after sieving.

[0025] An application of the cobalt-molybdenum catalyst prepared by the above method: for the hydrogenation of CO2 / H2S to produce methanethiol.

[0026] Preferably, the reaction temperature for the hydrogenation of CO2 / H2S to produce methanethiol is 200~400 °C, and the reaction pressure is 1.5 MPa.

[0027] Preferably, the amount of cobalt-molybdenum catalyst used is 1 g; the composition and content of the feed gas by volume percentage are: 4% H2S, 4% H2 and 1% CO2, with N2 as the balance gas; the feed gas flow rate is 5 mL·min. -1 .

[0028] The present invention has the following advantages and beneficial effects:

[0029] 1. The cobalt-molybdenum catalyst prepared by this invention has the characteristics of uniform dispersion of active components and suitable surface alkalinity, and the raw materials are inexpensive and the preparation process is simple, thus having broad application prospects.

[0030] 2. The cobalt-molybdenum catalyst prepared by this invention has abundant sulfur vacancies, which promotes the adsorption and activation of CO2 and H2S, and has good activity in the hydrogenation of CO2 / H2S to produce methanethiol;

[0031] 3. This invention uses titanium as a modifying additive and ethanol as a structure directing agent to synthesize a lamellar-like hydrotalcite precursor via a simple hydrothermal method. Based on this, active components are further loaded to ultimately obtain a highly dispersed, vacancy-rich cobalt-molybdenum catalyst. The addition of ethanol regulates the growth direction of the hydrotalcite structure, forming a lamellar morphology conducive to the dispersion of active components and promoting full exposure of active sites. The addition of titanium increases the electron cloud density around the active components; the transferred electrons reduce the strength of Mo-S and Co-S bonds, making them more prone to breakage and forming sulfur defects, thus promoting the adsorption and activation of CO2 and H2S. Simultaneously, due to the injection of additional charge, MoS2 is induced to undergo a phase transition from the 2H phase to the 1T phase, improving its catalytic hydrogenation capacity during the reaction. Ultimately, the catalyst exhibits considerable catalytic activity in the CO2 / H2S hydrogenation to methanethiol reaction system. Attached Figure Description

[0032] Figure 1 The X-ray powder diffraction patterns of the hydrotalcite-like precursors prepared in Examples 1-3 and Comparative Example 1 of this invention are shown below.

[0033] Figure 2 The X-ray powder diffraction patterns of the multi-component oxides prepared in Examples 1-3 and Comparative Example 1 of this invention are shown below.

[0034] Figure 3 The X-ray powder diffraction patterns are those of the cobalt-molybdenum catalysts prepared in Examples 1-3 and Comparative Example 1 of this invention.

[0035] Figure 4 The images show the Raman spectra of the cobalt-molybdenum catalysts prepared in Examples 1-3 and Comparative Example 1 of this invention.

[0036] Figure 5 The EPR spectra of the cobalt-molybdenum catalysts prepared in Examples 1-3 and Comparative Example 1 of this invention are shown below.

[0037] Figure 6 The S 2p XPS spectra of the cobalt-molybdenum catalysts prepared in Examples 1-3 and Comparative Example 1 of this invention are shown below.

[0038] Figure 7 The above are H2-TPR diagrams of the cobalt-molybdenum catalysts prepared in Examples 1-3 and Comparative Example 1 of this invention.

[0039] Figure 8 The images show SEM images of the cobalt-molybdenum catalysts prepared in Examples 1-3 and Comparative Example 1 of this invention.

[0040] Figure 9 This is a TEM image of Embodiment 1 of the present invention;

[0041] Figure 10 The conversion rate of CO2 in the CO2 / H2S hydrogenation to methanethiol reaction of the catalysts prepared in Examples 1-3 and Comparative Example 1 of this invention;

[0042] Figure 11 The selectivity of methanethiol in the CO2 / H2S hydrogenation to methanethiol reaction of the catalysts prepared in Examples 1-3 and Comparative Example 1 of the present invention is shown.

[0043] Figure 12 The yield of methanethiol in the CO2 / H2S hydrogenation to methanethiol reaction of the catalysts prepared in Examples 1-3 and Comparative Example 1 of this invention. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the embodiments and accompanying drawings. The examples described are further illustrations of this invention and are not intended to limit the scope of this invention.

[0045] Example 1

[0046] A method for preparing a cobalt-molybdenum catalyst: 165 μL of TiCl4 was dissolved in 30 mL of anhydrous ethanol and stirred continuously for half an hour. 3 mmol of Co(NO3)2·6H2O, 1.5 mmol of Al(NO3)3·9H2O, and 18 mmol of urea were dissolved sequentially in 60 mL of deionized water. The solutions were mixed and stirred continuously for half an hour. The mixture was then poured into a 150 mL hydrothermal reactor and reacted at 140 °C for 12 hours. After the temperature of the hydrothermal reactor cooled to room temperature, the precipitate was removed, filtered, washed, and dried in an 80 °C oven to obtain a ternary hydrotalcite precursor, named CoAl1Ti1-LDH. After calcination at 450 °C for 4 hours, a ternary oxide, named CoAl1Ti1-LDO, was obtained. An aqueous solution containing 0.3066 g of ammonium heptamolybdate and 0.24 g of potassium carbonate was prepared using an equal-volume impregnation method, and 1 g of the above-mentioned ternary oxide support was added. After drying at 80 °C for 12 hours, the product was placed in a muffle furnace and calcined at 400 °C for 2 hours. After cooling to room temperature, it was in-situ sulfided at 400 °C for 8 hours in sulfiding gas (volume fraction 10% H2S / H2) to obtain the final product named K2Mo / CoAl1Ti1-S.

[0047] Example 2

[0048] A method for preparing a cobalt-molybdenum catalyst: 82 μL of TiCl4 was dissolved in 30 mL of anhydrous ethanol and stirred continuously for half an hour. 3 mmol of Co(NO3)2·6H2O, 2.25 mmol of Al(NO3)3·9H2O, and 18 mmol of urea were dissolved sequentially in 60 mL of deionized water. The solutions were mixed and stirred continuously for half an hour. The mixture was then poured into a 150 mL hydrothermal reactor and reacted at 140 °C for 12 hours. After the temperature of the hydrothermal reactor cooled to room temperature, the precipitate was removed, filtered, washed, and dried in an 80 °C oven to obtain a ternary hydrotalcite precursor, named CoAl3Ti1-LDH. After calcination at 450 °C for 4 hours, a ternary oxide, named CoAl3Ti1-LDO, was obtained. An aqueous solution containing 0.3066 g of ammonium heptamolybdate and 0.24 g of potassium carbonate was prepared using an equal-volume impregnation method, and 1 g of the above-mentioned ternary oxide support was added. After drying at 80 °C for 1 hour, the product was placed in a muffle furnace and calcined at 400 °C for 2 hours. After cooling to room temperature, it was in-situ sulfided at 400 °C for 8 hours in sulfiding gas (volume fraction 10% H2S / H2) to obtain the final product named K2Mo / CoAl3Ti1-S.

[0049] Example 3

[0050] A method for preparing a cobalt-molybdenum catalyst: 220 μL of TiCl4 was dissolved in 30 mL of anhydrous ethanol and stirred continuously for half an hour. 3 mmol of Co(NO3)2·6H2O, 1 mmol of Al(NO3)3·9H2O, and 18 mmol of urea were dissolved sequentially in 60 mL of deionized water. The solutions were mixed and stirred continuously for half an hour. The mixture was then poured into a 150 mL hydrothermal reactor and reacted at 140 °C for 12 hours. After the reactor temperature cooled to room temperature, the precipitate was removed, filtered, washed, and dried in an 80 °C oven to obtain a ternary hydrotalcite precursor, named CoAl1Ti2-LDH. This precursor was then calcined at 450 °C for 4 hours to obtain a ternary oxide, named CoAl1Ti2-LDO. An aqueous solution containing 0.3066 g of ammonium heptamolybdate and 0.24 g of potassium carbonate was prepared using an equal-volume impregnation method, and 1 g of the above-mentioned ternary oxide support was added. After drying at 80 °C for 12 hours, the product was placed in a muffle furnace and calcined at 400 °C for 2 hours. After cooling to room temperature, it was in-situ sulfided at 400 °C for 8 hours in sulfiding gas (volume fraction 10% H2S / H2) to obtain the final product, named K2Mo / CoAl1Ti2-S.

[0051] Comparative Example 1

[0052] A method for preparing a cobalt-molybdenum catalyst: 3 mmol of Co(NO3)2·6H2O, 3 mmol of Al(NO3)3·9H2O, and 18 mmol of urea were successively dissolved in a mixed solution containing 30 mL of anhydrous ethanol and 60 mL of deionized water, and stirred continuously for half an hour. The mixed solution was then poured into a 150 mL hydrothermal reactor and reacted at 140 °C for 12 hours. After the hydrothermal reactor cooled to room temperature, the precipitate was removed, filtered, washed, and dried in an 80 °C oven to obtain a binary hydrotalcite precursor, named CoAl-LDH. This precursor was then calcined at 450 °C for 4 hours to obtain a binary oxide, named CoAl-LDO. An aqueous solution containing 0.3066 g of ammonium heptamolybdate and 0.24 g of potassium carbonate was prepared using an equal-volume impregnation method, and 1 g of the above-mentioned binary oxide support was added. After drying at 80 °C for 12 hours, the product was placed in a muffle furnace and calcined at 400 °C for 2 hours. After cooling to room temperature, it was in-situ sulfided at 400 °C for 8 hours in sulfiding gas (volume fraction 10% H2S / H2) to obtain the final product, named K2Mo / CoAl-S.

[0053] X-ray powder diffraction (XRD): The phase characterization of the samples was performed using an X'pert pro powder diffractometer from Panalytical, with an X'celerator as the detector, a copper target (Cu Kα, λ = 0.154 nm) as the excitation source, an operating voltage of 45 kV, and an operating current of 40 mA.

[0054] Raman spectroscopy: Structural information of the sample was analyzed using an in-Via Reflex Raman spectrometer (RENIS-HAW, UK). The scanning range was 300–2500 cm⁻¹. –1 The excitation source was λ = 325 nm, the exposure time was 2~10 s, the laser intensity was 1%, and the number of scans was 6.

[0055] Electron paramagnetic resonance (EPR) spectroscopy: Information on defects or sulfur vacancies in the sample can be obtained using an EPR200M electron paramagnetic resonance spectrometer (domestic). Testing is performed at low temperature at a frequency of 100 kHz. After placing the sample in a quartz test tube, the tube must be kept vertical, and the instrument's operating environment must be stable with adequate air circulation.

[0056] X-ray photoelectron spectroscopy (XPS): The elemental composition and chemical state of the catalyst surface were analyzed using an EscaLab 250Xi spectrometer. The excitation source was an Al target Kα beam, and the vacuum level in the analysis chamber was <10. -8 The excitation power was 22.5 W, and the binding energy of C 1s at 284.8 eV was used for calibration.

[0057] H2 temperature-programmed reduction (H2-TPR): The reduction performance of the samples was analyzed using an AutoChem 2920II chemisorption analyzer. 100 mg of catalyst was loaded into a U-shaped quartz tube and pretreated at 300 °C for 60 minutes under argon atmosphere (30 mL / min). After cooling to room temperature, the temperature was increased to 900 °C (10 °C / min) under a 10% H2 / Ar atmosphere for reduction. The reduction signal was recorded using a TCD detector.

[0058] Field emission scanning electron microscopy (SEM): The morphology of the catalyst was observed using an S-4800 field emission scanning electron microscope. The vacuum level in the analysis chamber was less than 2.7 × 10⁻⁶. –6 Pa, scanning voltage and current were 5 kV and 7 μA, respectively. The sample powder was adhered to conductive adhesive and sputtered with gold before observation.

[0059] Field emission transmission electron microscopy (TEM): TEM images of the samples were observed on a Tecnai G2 F20 transmission electron microscope with an accelerating voltage of 200 kV.

[0060] Figure 1 The X-ray powder diffraction patterns of the hydrotalcite-like precursors prepared in Examples 1-3 and Comparative Example 1 of this invention are shown in the figures. As can be seen from the figures, diffraction peaks appeared at 11.7, 23.6, 34.6, 39.3, 47.0 and 60.3° for all four samples, which belong to the (003), (006), (012), (015), (018) and (110) crystal planes of hydrotalcite-like precursors, respectively, indicating that the prepared precursors were all hydrotalcite.

[0061] Figure 2 The X-ray powder diffraction patterns of the multi-component oxides prepared in Examples 1-3 and Comparative Example 1 of this invention are shown. As can be seen from the figures, all four samples exhibit diffraction peaks of Co3O4, while no characteristic peaks of Al2O3 were observed, indicating that it exists in an amorphous form. However, in the samples with the addition of a titanium source, diffraction peaks belonging to the (101) crystal plane of TiO2 appear at position 25.3°, indicating that titanium mainly exists in the form of titanium dioxide.

[0062] Figure 3 The X-ray powder diffraction patterns of the cobalt-molybdenum catalysts prepared in Examples 1-3 and Comparative Example 1 of this invention are shown. As can be seen from the figures, all four samples exhibit characteristic peaks of Co9S8 (JCPDS 65-1765) and Co3S4 (JCPDS 42-1448), indicating that molybdenum and cobalt mainly exist in the form of sulfides. The characteristic peak of the (002) crystal plane belonging to MoS2 (JCPDS 37-1492) is shifted to approximately 9.0°, indicating the formation of the 1T phase MoS2.

[0063] Figure 4 The images show the Raman spectra of the cobalt-molybdenum catalysts prepared in Examples 1-3 and Comparative Example 1 of this invention. As can be seen from the figures, all four samples exhibit MoS₂ and CoS₂. x A 1g The presence of vibrational modes, including J1, J2, and J3 vibrational modes of 1T-MoS2, indicates that the catalyst CoS x It coexists with MoS2.

[0064] Figure 5 The figures show the EPR spectra of the cobalt-molybdenum catalysts prepared in Examples 1-3 and Comparative Example 1 of this invention. As can be seen from the figures, all four samples contain a certain amount of sulfur vacancies. Peak intensity comparison reveals that titanium modification can effectively increase the sulfur vacancy concentration in the catalyst.

[0065] Figure 6 The figures show the S 2p XPS spectra of the cobalt-molybdenum catalysts prepared in Examples 1-3 and Comparative Example 1 of this invention. As can be seen from the figures, all four samples contain four sulfur species: S... 2- (161.2 eV), S- (161.9 eV), SO3 - (164.9 eV) and SO4 2- (168.2 eV) Compared with the unmodified K2Mo / CoAl-S, the low-valence sulfur binding energy peak of the other catalysts shifted to a lower value, indicating that sulfur vacancies are more easily generated after modification. The abundant sulfur vacancies can promote the adsorption and activation of H2S and CO2.

[0066] Figure 7 The figures show the H2-TPR spectra of the cobalt-molybdenum catalysts prepared in Examples 1-3 and Comparative Example 1 of this invention. As can be seen from the figures, all four samples exhibit two H2 reduction peaks. The reduction peak around 200-400 °C is attributed to the reduction of unsaturated sulfur atoms adsorbed on sulfur vacancies, and its intensity and position are correlated with the Mo-S bond strength. The peak around 500-650 °C is attributed to MoS2 and CoS2. x Reduction of sulfur species. The results show that the addition of an appropriate titanium source can generate more sulfur vacancies and promote the production of more active components.

[0067] Figure 8 The images show SEM images of the cobalt-molybdenum catalysts prepared in Examples 1-3 and Comparative Example 1 of this invention. As can be seen from the images, all four samples exhibit a plate-like, stacked morphology.

[0068] Figure 9 The image shows a TEM image of Example 1 of the present invention. The image shows a sheet-like structure, and lattice fringes belonging to MoS2, Co3S4, Co9S8 and TiO2 can be observed from the image, proving that Co3S4, Co9S8 and MoS2 coexist in the prepared cobalt-molybdenum catalyst.

[0069] Performance testing of CO2 / H2S hydrogenation to methanethiol: The cobalt-molybdenum catalysts prepared in Examples 1-3 and Comparative Example 1 were used to evaluate the CO2 / H2S hydrogenation to methanethiol production. The test conditions were as follows: catalyst dosage was 1 g; feed gas composition and content (by volume percentage) were: 4% H2S, 4% H2, and 1% CO2, with N2 as the equilibrium gas; feed gas flow rate was 5 mL / min. -1 The reaction temperature is 200~400 ℃; the reaction pressure is 1.5MPa.

[0070] Figures 10-12 Table 1 shows the activity results of the cobalt-molybdenum catalysts prepared in Examples 1-3 and Comparative Example 1 in the CO2 / H2S hydrogenation to methanethiol reaction. The specific test results are shown in Table 1. Compared with the catalyst without a titanium source, the modified cobalt-molybdenum catalyst exhibits higher CO2 conversion and methanethiol yield due to the generation of more sulfur vacancies.

[0071] Table 1. Activity test results of the cobalt-molybdenum catalysts prepared in Examples 1-3 and Comparative Example 1 of this invention.

[0072]

[0073] In summary, the cobalt-molybdenum catalyst prepared by this invention has considerable catalytic performance in the CO2 / H2S hydrogenation to methanethiol reaction, among which the K2Mo / CoAl1Ti1-S sample exhibits the highest catalytic activity.

[0074] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a cobalt-molybdenum catalyst for the hydrogenation of CO2 / H2S to methanethiol, characterized in that: Includes the following steps: (1) Measure 50~500 μL of titanium source and dissolve it in 30 mL of anhydrous ethanol, and stir continuously for half an hour; (2) Dissolve 1-5 mmol of cobalt source, 1-5 mmol of aluminum source and 10-30 mmol of precipitant in 60 mL of deionized water in sequence; (3) After mixing the solutions obtained in steps (1) and (2), stir continuously for half an hour; (4) Pour the mixed solution obtained in step (3) into a hydrothermal reactor and react at 120~150 °C; (5) After the temperature of the hydrothermal reactor drops to room temperature, the obtained precipitate is filtered, washed and placed in an oven to dry, thus obtaining the modified ternary hydrotalcite precursor. (6) The precursor obtained in step (5) is calcined at a certain temperature to obtain a ternary oxide; (7) Soluble molybdenum salt and potassium salt are impregnated on the ternary oxide by equal volume impregnation method, and the cobalt-molybdenum catalyst is obtained by calcination and sulfidation.

2. The method for preparing a cobalt-molybdenum catalyst for the hydrogenation of CO2 / H2S to methanethiol according to claim 1, characterized in that: The titanium source mentioned in step (1) is titanium tetrachloride or tetraisopropyl titanate.

3. The method for preparing a cobalt-molybdenum catalyst for the hydrogenation of CO2 / H2S to methanethiol according to claim 1, characterized in that: The cobalt source mentioned in step (2) is Co(NO3)2·6H2O or CoCl2·6H2O, the aluminum source is Al(NO3)3·9H2O or AlCl3·9H2O, and the precipitant is urea.

4. The method for preparing a cobalt-molybdenum catalyst for the hydrogenation of CO2 / H2S to methanethiol according to claim 1, characterized in that: The reaction time in step (4) is 10 to 20 hours.

5. The method for preparing a cobalt-molybdenum catalyst for the hydrogenation of CO2 / H2S to methanethiol according to claim 1, characterized in that: The drying temperature in step (5) is 80~100 ℃.

6. The method for preparing a cobalt-molybdenum catalyst for the hydrogenation of CO2 / H2S to methanethiol according to claim 1, characterized in that: In step (6), the roasting temperature is 400~500 ℃ and the roasting time is 2~5 h.

7. The method for preparing a cobalt-molybdenum catalyst for the hydrogenation of CO2 / H2S to methanethiol according to claim 1, characterized in that: The soluble molybdenum salt mentioned in step (7) is ammonium heptamolybdate or ammonium tetramolybdate, and the potassium salt is potassium carbonate.

8. The method for preparing a cobalt-molybdenum catalyst for the hydrogenation of CO2 / H2S to methanethiol according to claim 1, characterized in that: The roasting temperature in step (7) is 400~500 ℃ and the roasting time is 2~5 h.

9. A cobalt-molybdenum catalyst prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the cobalt-molybdenum catalyst according to claim 9 in the production of methanethiol by CO2 / H2S hydrogenation, characterized in that: When used for the hydrogenation of CO2 / H2S to produce methanethiol, the reaction temperature is 200~400 ℃, and the reaction pressure is 1.5~1.8 MPa; the feed gas composition by volume percentage is: 1% CO2, 4% H2S, 4% H2, with N2 as the equilibrium gas, and the feed gas flow rate is 5 mL·min. -1 The catalyst dosage is 1 g.

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