A ruthenium-based catalyst, its preparation method and use

Abstract

The application provides a ruthenium-based catalyst and a preparation method and application thereof, and belongs to the technical field of catalytic materials. A ruthenium source is mixed with a carrier, and calcination is performed to obtain a precursor; the precursor (or the reduced precursor) is mixed with a sulfur source, and modification treatment is performed through calcination or an atomic layer deposition multi-pulse strategy to obtain the ruthenium-based catalyst. When the ruthenium-based catalyst prepared by the application is applied to catalyze a CO2 hydrogenation reaction, high selectivity of the catalytic CO2 hydrogenation to generate CO can be realized. Meanwhile, the ruthenium-based catalyst prepared by the application has high CO2 catalytic hydrogenation activity and excellent high-temperature stability, has good applicability, breaks through the limitations of a carrier and the loading amount of an active metal Ru, can realize modification of a metal Ru catalyst loaded on different carriers, realizes cyclic catalytic conversion of a simulated CO2 hydrogenation tail gas, and realizes catalytic conversion of a sulfur-containing CO2 reaction gas and a sulfur-containing CO2 tail gas in industry.

Description

Technical Field

[0001] This invention belongs to the field of catalytic materials technology, specifically relating to a ruthenium-based catalyst, its preparation method, and its application. Background Technology

[0002] The overexploitation of fossil resources has led to a sharp increase in atmospheric CO2 levels, disrupting the original cycles and balance of ecosystems and causing numerous environmental problems such as ocean acidification and the greenhouse effect, seriously impacting human living environments and the long-term sustainable development of society. Therefore, reducing carbon emissions to address climate change has gradually become a global consensus.

[0003] CO2 is not only a greenhouse gas, but also a cheap and abundant carbon source. Its conversion and utilization can not only solve the environmental problems caused by excessive CO2 emissions, but also realize the high-value utilization of CO2, which has the dual significance of "carbon emission reduction" and "resource utilization".

[0004] Catalytic CO2 hydrogenation to CO, also known as Reverse Water-Gas Shift (RWGS), produces CO, an important platform compound molecule that can be further synthesized into various fuels and high-value-added chemicals through Fischer-Tropsch synthesis, carbonylation, and other processes, thus possessing great potential for large-scale application. However, the difficulty in activating CO2 molecules and the complexity of hydrogenation products lead to problems such as low CO2 conversion and low selectivity for the target product CO. Furthermore, due to thermodynamic limitations, RWGS typically requires high reaction temperatures, demanding high-temperature stability from the catalyst. Therefore, it is necessary to design and synthesize RWGS catalysts with high activity, high CO selectivity, and excellent high-temperature stability to achieve efficient and directional catalytic conversion of CO2 hydrogenation to achieve highly selective CO production.

[0005] Ru-based catalysts are widely used in the catalytic hydrogenation of CO2 due to their excellent hydrogen activation capabilities. However, traditional supported Ru-based single-metal catalysts for CO2 hydrogenation primarily produce CH4, with extremely low CO selectivity. Currently reported Ru-based catalysts achieving selective CO production suffer from problems such as poor activity (low CO2 conversion), relatively low CO selectivity (<95%), and poor stability (agglomeration of active Ru single atoms, leading to decreased CO selectivity), or strong dependence on specific metal oxide supports (such as anatase TiO2 and MoO3 supports), resulting in poor performance in the catalytic hydrogenation of CO2 to CO synthesis. Summary of the Invention

[0006] The purpose of this invention is to provide a ruthenium-based catalyst, its preparation method, and its applications. The ruthenium-based catalyst prepared by this invention can achieve highly selective CO (CO>99%) catalytic hydrogenation of CO2. Furthermore, the ruthenium-based catalyst exhibits high catalytic activity for CO2 hydrogenation and excellent high-temperature stability, capable of withstanding high-temperature oxidizing or reducing atmospheres without altering the catalyst's product selectivity. It has good applicability, overcomes the limitations of different supports, and can achieve highly selective CO production from CO2 hydrogenation catalyzed by Ru supported on various supports. Moreover, it can realize the cyclic catalytic conversion of simulated CO2 hydrogenation tail gas, and also achieves the catalytic conversion of sulfur-containing CO2 reaction gas and sulfur-containing CO2 tail gas from industrial applications.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] This invention provides a method for preparing a ruthenium-based catalyst, comprising the following steps:

[0009] A ruthenium source is mixed with a support and calcined to obtain a precursor; the support includes at least one of a metal oxide support, a carbon material support, a boron nitride support, and a silicon carbide support; the metal oxide support includes at least one of a titanium dioxide support, a cerium dioxide support, and a zirconium dioxide support.

[0010] The precursor was mixed with a sulfur source and modified by calcination or a multi-pulse atomic layer deposition strategy to obtain the ruthenium-based catalyst.

[0011] The ruthenium-based catalyst comprises a support and an active substance Ru and a sulfur species supported on the support; the loading of the active substance Ru is 1–15 wt%; and the loading of the sulfur species is 0.001–1 wt%.

[0012] Preferably, the ruthenium source includes at least one of ruthenium chloride, ruthenium chloride hydrate, ruthenium acetate, ruthenium nitrate, ruthenium acetylacetonate, and ruthenium bromide.

[0013] Preferably, the sulfur source includes at least one of elemental sulfur, potassium sulfide, hydrogen sulfide, sulfur dioxide, thiols, benzenesulfonic acid, and thioethers.

[0014] Preferably, the roasting temperature is 350–800°C, and the holding time is 1–24 hours.

[0015] Preferably, when the sulfur source is non-gaseous, the modification treatment is calcination; the calcination temperature is 150–700°C, and the holding time is 0.1–24 h; the molar ratio of ruthenium in the ruthenium source to sulfur in the sulfur source is 0.1–200:1.

[0016] When the sulfur source is gaseous, the modification treatment is a calcination or atomic layer deposition multi-pulse strategy, and the modification treatment is carried out in a sulfur-containing atmosphere;

[0017] When the modification treatment is calcination, the volume fraction of the sulfur source in the sulfur-containing atmosphere is 0.01% to 100%; the calcination temperature is 150 to 600°C, and the holding time is 0.001 to 24 hours.

[0018] When the modification treatment is an atomic layer deposition (ALD) multi-pulse strategy, the volume fraction of sulfur source in the sulfur-containing atmosphere is 0.1-10%; the operating temperature of the ALD multi-pulse strategy is 100-550℃; the single pulse time of the sulfur-containing atmosphere is 0.1-3s; and the number of pulse cycles is 1-3000. Nitrogen gas is used as a carrier during the pulse process of the ALD multi-pulse strategy, and the flow rate of the nitrogen gas is 30-150mL / min.

[0019] Preferably, the modification process further includes: reducing the precursor in an H2 atmosphere; the volume fraction of H2 in the H2 atmosphere is 1% to 100%; the temperature of the reduction process is 250 to 800°C, and the holding time is 0.3 to 24 hours.

[0020] Preferably, the modification process further includes: subjecting the obtained modified material to heat treatment; the heat treatment temperature is 300–750°C, and the holding time is 1–72 h.

[0021] This invention provides a ruthenium-based catalyst prepared by the preparation method described in the above technical solution.

[0022] This invention provides the application of the ruthenium-based catalyst described in the above technical solution in the catalytic CO2 hydrogenation reaction.

[0023] Preferably, the reactant gas for the catalytic CO2 hydrogenation reaction includes H2, CO2, and N2; the volume ratio of H2, CO2, and N2 in the reactant gas is 45–80:10–45:10–20; the temperature of the catalytic CO2 hydrogenation reaction is 350–750°C, and the pressure is 0.1 MPa.

[0024] This invention provides a method for preparing a ruthenium-based catalyst, comprising the following steps: mixing a ruthenium source with a support and calcining to obtain a precursor; mixing the precursor with a sulfur source and modifying it through calcination or a multi-pulse atomic layer deposition strategy to obtain the ruthenium-based catalyst. Specifically, this invention modifies the synthesized catalyst precursor with sulfur (S) and precisely controls the content of S-modified species on the surface of the active metal Ru in the obtained ruthenium-based catalyst through calcination or a multi-pulse atomic layer deposition strategy, thereby constructing a highly active, highly CO-selective, and excellent high-temperature stable S-modified Ru-based catalyst. In the ruthenium-based catalyst of this invention, the S-modified species are bound to the surface of the active metal Ru, changing the electronic state and surface chemical properties of the active metal Ru, thereby changing the adsorption strength of the ruthenium-based catalyst for reactants (such as H2, CO2) and product CO, making the desorption of product CO easier. The ruthenium-based catalyst obtained by the preparation method provided by this invention is an inorganic sulfur-modified catalyst that achieves highly selective CO (CO>99%) catalytic hydrogenation of CO2. Furthermore, this catalyst has high catalytic activity for CO2 hydrogenation and excellent high-temperature stability. It can withstand high-temperature oxidizing or reducing atmospheres without changing the product selectivity. It has good applicability, overcomes the limitations of the support, and can operate for a long time under high-temperature reaction conditions while maintaining unchanged catalytic activity and selectivity.

[0025] Furthermore, due to the strong coordination interaction between S and Ru, even after the ruthenium-based catalyst undergoes high-temperature reduction and oxidation treatment, the S-modified species can still bind to the surface of the active Ru metal without changing the catalytic CO2 hydrogenation selectivity, and still exhibit excellent high-temperature stability under oxidizing and reducing atmospheres.

[0026] This invention also provides the application of a ruthenium-based catalyst in the catalytic hydrogenation reaction of CO2. In this invention, the ruthenium-based catalyst is stable under high-temperature oxidizing atmospheres. Even after prolonged exposure to a high-temperature air atmosphere (oxidizing atmosphere) of 450–550°C, the product selectivity of the CO2 hydrogenation reaction remains unchanged, exhibiting extremely high stability against oxidizing atmospheres. Simultaneously, the ruthenium-based catalyst can achieve high CO selectivity across a wide H2 / CO2 volume ratio (H2 to CO2 volume ratio of 45–80:10–45). Examples show that even at an H2 / CO2 volume ratio as high as 8 / 1, the CO selectivity of the ruthenium-based catalyst remains ≥99%. Moreover, the ruthenium-based catalyst exhibits resistance to sulfur poisoning, enabling the catalytic conversion of sulfur-containing CO2 reaction gas and industrial sulfur-containing CO2 tail gas. Furthermore, the ruthenium-based catalyst significantly inhibits the catalytic hydrogenation activity of CO, resulting in extremely low CO catalytic hydrogenation activity. Therefore, it can achieve the cyclic catalytic conversion of CO2 catalytic reaction tail gas (containing product CO) and simultaneously achieve efficient catalytic conversion and utilization of CO2 in the reactants, preventing further hydrogenation of CO in the resulting reaction products to form CH4. This reduces the cost of CO2 enrichment and purification, possessing significant economic importance and enormous potential for industrial application. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 20 at different temperatures.

[0029] Figure 2 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 21(a) at different temperatures;

[0030] Figure 3 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 21(b) at different temperatures;

[0031] Figure 4 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 21(c) at different temperatures;

[0032] Figure 5 The graph shows the high-temperature stability test results of the catalyst in Example 21(d);

[0033] Figure 6The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 22 at different temperatures.

[0034] Figure 7 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 23 at 450°C.

[0035] Figure 8 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 24 at different temperatures.

[0036] Figure 9 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 25 at different temperatures.

[0037] Figure 10 The graph shows the CO2 catalytic hydrogenation performance of the catalysts in Examples 26-28 at different temperatures;

[0038] Figure 11 The graph shows the CO2 catalytic hydrogenation performance of the catalysts in Examples 29-32 at different temperatures;

[0039] Figure 12 The graph shows the CO2 catalytic hydrogenation performance of the catalysts in Examples 33-36 at different temperatures;

[0040] Figure 13 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 37 at different temperatures;

[0041] Figure 14 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 38 at different temperatures.

[0042] Figure 15 The graph shows the high-temperature stability test results of the catalyst in Example 39;

[0043] Figure 16 The graph shows the catalytic hydrogenation performance of the catalyst in Example 40 on the tail gas of the simulated cyclic CO2 hydrogenation reaction.

[0044] Figure 17 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Comparative Example 2(a) at different temperatures;

[0045] Figure 18 The figure shows the high-temperature stability test results of the catalyst in Comparative Example 2(b) at 550℃;

[0046] Figure 19 The graph shows the CO catalytic hydrogenation performance of the catalyst in Comparative Example 3 at different temperatures.

[0047] Figure 20 The graph shows the CO catalytic hydrogenation performance of the catalyst in Comparative Example 4 at different temperatures. Detailed Implementation

[0048] This invention provides a method for preparing a ruthenium-based catalyst, comprising the following steps:

[0049] A ruthenium source is mixed with a support and calcined to obtain a precursor; the support includes at least one of a metal oxide support, a carbon material support, a boron nitride support, and a silicon carbide support; the metal oxide support includes at least one of a titanium dioxide support, a cerium dioxide support, and a zirconium dioxide support.

[0050] The precursor was mixed with a sulfur source and modified by calcination or a multi-pulse atomic layer deposition strategy to obtain the ruthenium-based catalyst.

[0051] The ruthenium-based catalyst comprises a support and an active substance Ru and a sulfur species supported on the support; the loading of the active substance Ru is 1–15 wt%; and the loading of the sulfur species is 0.001–1.0 wt%.

[0052] In this invention, unless otherwise specified, all raw materials used are commercially available products known to those skilled in the art or prepared using methods known to those skilled in the art.

[0053] In this invention, a ruthenium source is mixed with a support and then calcined to obtain a precursor.

[0054] In this invention, the ruthenium source preferably includes at least one selected from ruthenium chloride, ruthenium chloride hydrate, ruthenium acetate, ruthenium nitrate, ruthenium acetylacetonate, and ruthenium bromide, more preferably ruthenium chloride, ruthenium chloride hydrate, ruthenium acetate, ruthenium nitrate, ruthenium acetylacetonate, or ruthenium bromide. In the embodiments of this invention, RuCl3·xH2O is used.

[0055] In this invention, the carrier includes at least one of a metal oxide carrier, a carbon material carrier, a boron nitride carrier, and a silicon carbide carrier, preferably a metal oxide carrier, a carbon material carrier, or a boron nitride carrier. In this invention, the metal oxide carrier includes at least one of a titanium dioxide carrier, a cerium dioxide carrier, and a zirconium dioxide carrier, preferably a titanium dioxide carrier, a cerium dioxide carrier, or a zirconium dioxide carrier; the carbon material carrier is preferably at least one of a graphene carrier and a carbon black carrier, more preferably a graphene carrier; the boron nitride carrier is preferably a hexagonal boron nitride carrier.

[0056] In this invention, a ruthenium source is preferably mixed with deionized water to obtain a dispersion; a carrier is mixed with the dispersion, and the water is evaporated by stirring and heating to obtain a solid material; the solid material is then dried and ground sequentially to obtain a pulverized material. In this invention, the stirring, heating, and evaporation of water is preferably carried out under water bath or oil bath conditions; the temperature for stirring, heating, and evaporation of water is preferably 25–200°C, more preferably 40–100°C. In this invention, the drying temperature is preferably 60–150°C, more preferably 110°C; the drying time is preferably 3–24 hours, more preferably 8–12 hours. In an embodiment of this invention, the overnight drying time is 8 hours. After obtaining the pulverized material, this invention calcines the pulverized material to obtain a precursor. This invention has no requirements on the calcination atmosphere and can use an air atmosphere, an inert atmosphere, or a reducing atmosphere. In an embodiment of this invention, the calcination is carried out in an air atmosphere; the calcination temperature is preferably 350–800°C, more preferably 450–600°C; the holding time is preferably 1–24 hours, more preferably 3–10 hours.

[0057] After obtaining the precursor, the present invention mixes the precursor with a sulfur source and modifies it by calcination or atomic layer deposition multi-pulse strategy to obtain the ruthenium-based catalyst.

[0058] Before the modification treatment, the precursor is preferably reduced in an H2-containing atmosphere to obtain a reduced precursor. In this invention, the volume fraction of H2 in the H2-containing atmosphere is preferably 1%–100%, more preferably 5%–10%. In an embodiment of this invention, 5% H2 and 95% Ar are mixed for reduction treatment. The reduction treatment temperature is preferably 250–800°C, more preferably 400–600°C; the holding time is preferably 0.3–24 h, more preferably 1–3 h. In this invention, the modification treatment aims to bind S-modified species to the surface of the active metal Ru, altering the surface chemical properties of Ru, thereby affecting the adsorption capacity and strength of reactant molecules, reaction intermediates, and products, thus selectively converting the CO2 hydrogenation product from unmodified CH4 to S-modified CO.

[0059] After obtaining the reduction precursor, the present invention preferably modifies the reduction precursor. In the present invention, the sulfur source preferably includes at least one selected from elemental sulfur, potassium sulfide, hydrogen sulfide, sulfur dioxide, thiols, benzenesulfonic acid, and thioethers, more preferably elemental sulfur, potassium sulfide, hydrogen sulfide, sulfur dioxide, thiols, or thioethers.

[0060] In this invention, when the sulfur source is non-gaseous, the modification treatment is preferably carried out in an inert gas atmosphere; the modification treatment method is preferably calcination. In this invention, the inert gas is preferably Ar; the calcination temperature is preferably 150–700°C, more preferably 400–550°C; the calcination holding time is preferably 0.1–24 h, more preferably 1–3 h; the molar ratio of ruthenium in the ruthenium source to sulfur in the sulfur source is preferably 0.1–200:1, more preferably 1–50:1.

[0061] In this invention, when the sulfur source is gaseous, the modification treatment is preferably carried out in a sulfur-containing atmosphere; the modification treatment method is preferably calcination or atomic layer deposition (ALD) multi-pulse strategy. In this invention, when the modification treatment is calcination, the volume fraction of the sulfur source in the sulfur-containing atmosphere is preferably 0.01%–100%, more preferably 0.5%–30%; the calcination temperature is preferably 150–600°C, further preferably 300–600°C, more preferably 500–550°C; the holding time for the modification treatment is preferably 0.001–24 h, more preferably 0.001–3 h. In this invention, when the modification treatment is an ALD multi-pulse strategy, the volume fraction of the sulfur source in the sulfur-containing atmosphere is preferably 0.1%–10%, more preferably 1%–10%. In embodiments of this invention, the sulfur-containing atmosphere preferably includes a mixture of H2S and Ar. The operating temperature of the atomic layer deposition multi-pulse strategy described in this invention is preferably 100–550°C, more preferably 300–500°C; the single pulse duration of the sulfur-containing source atmosphere is preferably 0.1–3 s, more preferably 0.1–1 s; the number of pulse cycles of the sulfur-containing source atmosphere is preferably 1–3000, more preferably 10–2000. During the pulse process of the atomic layer deposition multi-pulse strategy described in this invention, nitrogen is preferably used as the carrier gas, and the nitrogen gas is preferably high-purity nitrogen (purity 99.99%); the flow rate of the nitrogen gas is preferably 30–150 mL / min, more preferably 50–100 mL / min.

[0062] Following the modification treatment, the present invention preferably subjectes the obtained modified material to heat treatment to obtain the ruthenium-based catalyst. In this invention, the heat treatment is preferably carried out in an air atmosphere; the heat treatment temperature is preferably 300–750°C, more preferably 500–650°C; and the holding time is preferably 1–72 h, more preferably 3–10 h. In this invention, the purpose of heat treatment under an oxidizing atmosphere is to regulate the content of S-modified species on the surface of the active metal Ru and to verify the stability of the obtained ruthenium-based catalyst under an oxidizing atmosphere.

[0063] The present invention also provides a ruthenium-based catalyst prepared by the preparation method described above, comprising a support and an active substance Ru and inorganic sulfur supported on the support. In the present invention, the loading of Ru is 1-15 wt%, preferably 1-10 wt%; the loading of inorganic sulfur is 0.001-1 wt%, preferably 0.001-0.5 wt%.

[0064] This invention also provides the application of the ruthenium-based catalyst described in the above-mentioned technical solution in the catalytic CO2 hydrogenation reaction. In this invention, the reactant gas for the catalytic CO2 hydrogenation reaction preferably includes H2, CO2, and N2; the volume ratio of H2, CO2, and N2 in the reactant gas is preferably 45–80:10–45:10–20, specifically 60:20:20, 72:18:10, 45:45:10, or 80:10:10. The reactant gas in this invention preferably also includes CO, and the volume percentage of CO in the reactant gas is preferably ≤30%. In one embodiment of this invention, the volume ratio of H2, CO2, CO, and N2 is 60:15:15:10. The temperature of the catalytic CO2 hydrogenation reaction in this invention is preferably 350–750°C, more preferably 400–600°C; the pressure is preferably 0.1 MPa.

[0065] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0066] The product information for the various carriers used in the embodiments is as follows:

[0067] Rutile powder carrier is commercially known as rutile TiO2, with a specification of 100g, and is sourced from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0068] The trade name of the P25 carrier is P25 TiO2, with a specification of 250GR, and it is sourced from Thermo Fisher Scientific.

[0069] The cerium dioxide (CeO2) carrier is commercially available under the name "Cerium Dioxide," in 100g packages, and is sourced from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0070] The zirconium dioxide (ZrO2) carrier is commercially available under the name zirconium dioxide, in 100g packages, and is sourced from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0071] In the embodiments of this invention, "overnight" refers to 8 hours.

[0072] Example 1

[0073] Weigh 60.0 mg RuCl3·xH2O and mix with 5 mL of deionized water. Under stirring, the RuCl3·xH2O is fully dispersed in the water to form a uniform dispersion. Weigh 1 g of Rutile powder carrier and place it in the dispersion. Under water bath conditions, heat the resulting liquid to 40°C and stir continuously to completely evaporate the water. Collect the solid material.

[0074] The solid material was placed in an oven and dried overnight at 110°C. After the dried solid material was ground for 10 minutes, it was placed on a ceramic boat and placed in a muffle furnace and calcined at 500°C for 3 hours in an air atmosphere. After calcination, the precursor was obtained.

[0075] 150 mg of the precursor was weighed and mixed with 75 mg of elemental S. The resulting mixture was placed in a tube furnace and modified at 550 °C for 3 h in an inert Ar atmosphere. After the modification was completed, a Ru-based catalyst was obtained, labeled as 2% Ru / Rutile-S.

[0076] Example 2

[0077] Weigh 60.0 mg RuCl3·xH2O and mix with 5 mL of deionized water. Under stirring, the RuCl3·xH2O is fully dispersed in the water to form a uniform dispersion. Weigh 1 g of Rutile powder carrier and place it in the dispersion. Under water bath conditions, heat the resulting liquid to 40°C and stir continuously to completely evaporate the water. Collect the solid material.

[0078] The solid material was placed in an oven and dried overnight at 110°C. After the dried solid material was ground for 10 minutes, it was placed on a ceramic boat and placed in a muffle furnace and calcined at 500°C for 3 hours in air. After calcination, the precursor was obtained.

[0079] Weigh 150 mg of the precursor and mix it with 75 mg of elemental S. Place the resulting mixture in a tube furnace and first modify it at 550 °C for 3 h in an inert Ar atmosphere, then heat treat it at 550 °C for 3 h in an air atmosphere. After the treatment, a Ru-based catalyst is obtained, labeled as 2% Ru / Rutile-SO (550 °C).

[0080] Example 3

[0081] The preparation method of the catalyst is basically the same as that in Example 2, except that the heat treatment temperature is adjusted to 650°C and the resulting catalyst is labeled as 2% Ru / Rutile-SO (650°C).

[0082] Example 4

[0083] Example 4(a)

[0084] Weigh 60.0 mg RuCl3·xH2O and mix with 5 mL of deionized water. Under stirring, the RuCl3·xH2O is fully dispersed in the water to form a uniform dispersion. Weigh 1 g of Rutile powder carrier and place it in the dispersion. Under water bath conditions, heat the resulting liquid to 40°C and stir continuously to completely evaporate the water. Collect the solid material.

[0085] The solid material was placed in an oven and dried overnight at 110°C. After the dried solid material was ground for 10 minutes, it was placed on a ceramic boat and placed in a muffle furnace and calcined at 500°C for 3 hours in an air atmosphere. After calcination, the precursor was obtained.

[0086] 50 mg of the precursor was weighed and reduced at 550 °C in a 20% H2 / Ar atmosphere for 1 h. Then, 0.5% H2S / Ar gas was pulsed and circulated onto its surface 5 times using an atomic layer deposition (ALD) multi-pulse strategy. The operating temperature of the ALD multi-pulse strategy was 200 °C. High-purity N2 was used as the carrier gas during the pulsation process (flow rate of 50 mL / min). The single pulse time of the 0.5% H2S / Ar mixed gas in the ALD multi-pulse strategy was 1 s. The resulting catalyst was labeled as 2% Ru / Rutile-5H2S.

[0087] Example 4(b)

[0088] With other conditions remaining unchanged, the number of pulse cycles of 0.5% H2S / Ar gas was adjusted to 300, and the scheme of Example 4(a) was repeated. The resulting catalyst was labeled as 2% Ru / Rutile-300H2S.

[0089] Example 5

[0090] Weigh 29.4 mg RuCl3·xH2O and mix with 5 mL of deionized water. Under stirring, the RuCl3·xH2O is fully dispersed in the water to form a uniform dispersion. Weigh 1 g of Rutile powder carrier and place it in the dispersion. Under water bath conditions, heat the resulting liquid to 40°C and stir continuously to completely evaporate the water. Collect the solid material.

[0091] The solid material was placed in an oven and dried overnight at 110°C. After the dried solid material was ground for 10 minutes, it was placed on a ceramic boat and placed in a muffle furnace and calcined at 500°C for 3 hours in air. After calcination, the precursor was obtained.

[0092] Weigh 120 mg of the precursor and mix it with 60 mg of elemental S. Place the resulting mixture in a tube furnace and first modify it at 550 °C for 3 h in an inert Ar atmosphere, then heat treat it at 550 °C for 3 h in an air atmosphere. After the treatment, a Ru-based catalyst is obtained, labeled as 1% Ru / Rutile-SO (550 °C).

[0093] Example 6

[0094] The preparation method of the catalyst is basically the same as that in Example 5, except that the mass of the RuCl3·xH2O precursor in Example 5 is replaced with 294.0 mg, and the resulting catalyst is labeled as 10% Ru / Rutile-SO (550℃).

[0095] Example 7

[0096] The preparation method of the catalyst is basically the same as that in Example 2, except that the Rutile powder support in Example 2 is replaced with a P25 support, and the resulting catalyst is labeled as 2% Ru / P25-SO (550℃).

[0097] Example 8

[0098] The preparation method of the catalyst is basically the same as that in Example 2, except that the Rutile powder support in Example 2 is replaced with cerium dioxide (CeO2) support, and the resulting catalyst is labeled as 2% Ru / CeO2-SO (550℃).

[0099] Example 9

[0100] The preparation method of the catalyst is basically the same as that in Example 2, except that the Rutile powder support in Example 2 is replaced with a zirconium dioxide (ZrO2) support, and the resulting catalyst is labeled as 2% Ru / ZrO2-SO (550℃).

[0101] Example 10

[0102] The preparation method of the catalyst is basically the same as that in Example 2, except that RuCl3·xH2O in Example 2 is replaced with ruthenium acetate with the same Ru molar content.

[0103] Example 11

[0104] The preparation method of the catalyst is basically the same as that in Example 2, except that RuCl3·xH2O in Example 2 is replaced with ruthenium nitrate with the same Ru molar content.

[0105] Example 12

[0106] The preparation method of the catalyst is basically the same as that in Example 2, except that RuCl3·xH2O in Example 2 is replaced with ruthenium acetylacetone with the same molar content of Ru.

[0107] Example 13

[0108] The preparation method of the catalyst is basically the same as that in Example 2, except that RuCl3·xH2O in Example 2 is replaced with ruthenium bromide with the same Ru molar content.

[0109] Example 14

[0110] Weigh 60.0 mg RuCl3·xH2O and mix with 5 mL of deionized water. Under stirring, the RuCl3·xH2O is fully dispersed in the water to form a uniform dispersion. Weigh 1 g of Rutile powder carrier and place it in the dispersion. Under water bath conditions, heat the resulting liquid to 40°C and stir continuously to completely evaporate the water. Collect the solid material.

[0111] The solid material was placed in an oven and dried overnight at 110°C. After the dried solid material was ground for 10 minutes, it was placed on a ceramic boat and placed in a muffle furnace and calcined at 500°C for 3 hours in air. After calcination, the precursor was obtained.

[0112] Weigh 150 mg of the precursor and place it in an H2S / Ar mixed atmosphere (H2S volume fraction of 0.5%). Modify it at 550 °C for 3 h. After the modification is completed, a Ru-based catalyst is obtained and labeled as 2% Ru / Rutile-H2S.

[0113] Example 15

[0114] The preparation method of the catalyst is basically the same as that in Example 2, except that the elemental sulfur in Example 2 is replaced with potassium sulfide.

[0115] Example 16

[0116] The preparation method of the catalyst is basically the same as that in Example 2, except that the elemental sulfur in Example 2 is replaced with thiols.

[0117] Example 17

[0118] The preparation method of the catalyst is basically the same as that in Example 2, except that the elemental sulfur in Example 2 is replaced with thioether.

[0119] Example 18

[0120] Weigh 60.0 mg RuCl3·xH2O and mix with 5 mL of deionized water. Under stirring, the RuCl3·xH2O is fully dispersed in the water to form a uniform dispersion. Weigh 1 g of Rutile powder carrier and place it in the dispersion. Under water bath conditions, heat the resulting liquid to 40°C and stir continuously to completely evaporate the water. Collect the solid material.

[0121] The solid material was placed in an oven and dried overnight at 110°C. After the dried solid material was ground for 10 minutes, it was placed on a ceramic boat and placed in a muffle furnace and calcined at 500°C for 3 hours in air. After calcination, the precursor was obtained.

[0122] The precursor was placed in an H2 / Ar mixed atmosphere (H2 volume fraction of 5%) and reduced at 550°C for 1 hour to obtain a reduced precursor.

[0123] 150 mg of the reduction precursor was weighed and physically mixed with 75 mg of elemental S. The mixture was placed in a tube furnace and modified at 550 °C for 3 h in an inert Ar atmosphere. After the modification was completed, a Ru-based catalyst was obtained, labeled as 2% Ru / Rutile-HS.

[0124] Example 19

[0125] Weigh 60.0 mg RuCl3·xH2O and mix with 5 mL of deionized water. Under stirring, the RuCl3·xH2O is fully dispersed in the water to form a uniform dispersion. Weigh 1 g of Rutile powder carrier and place it in the dispersion. Under water bath conditions, heat the resulting liquid to 40°C and stir continuously to completely evaporate the water. Collect the solid material.

[0126] The solid material was placed in an oven and dried overnight at 110°C. After the dried solid material was ground for 10 minutes, it was placed on a ceramic boat and placed in a muffle furnace and calcined at 500°C for 3 hours in air. After calcination, the precursor was obtained.

[0127] The precursor was placed in an H2 / Ar mixed atmosphere (H2 volume fraction of 5%) and reduced at 550°C for 1 hour to obtain a reduced precursor.

[0128] 150 mg of the reduction precursor was weighed and physically mixed with 75 mg of elemental S. The mixture was placed in a tube furnace and first reduced at 550 °C for 3 h in an inert Ar atmosphere, and then heat-treated at 550 °C for 3 h in an air atmosphere. After the treatment, a Ru-based catalyst was obtained, labeled as 2% Ru / Rutile-HSO.

[0129] Example 20

[0130] Example 20: Performance Evaluation of Catalytic CO2 Hydrogenation Reaction

[0131] The Ru-based catalyst (2% Ru / Rutile-S) prepared in Example 1 was evaluated for its catalytic performance in CO2 hydrogenation in a fixed-bed reactor. The catalyst performance evaluation was conducted in a fixed-bed reactor equipped with a quartz reaction tube with an inner diameter of 8 mm. The specific steps were as follows:

[0132] The Ru-based catalyst synthesized in Example 1 was sequentially compressed and sieved to prepare Ru-based catalyst powder with a particle size of 20-40 mesh. 50 mg of Ru-based catalyst powder was weighed and mixed evenly with 450 mg of quartz sand (particle size of 20-40 mesh). The Ru-based catalyst mixed with quartz sand was sandwiched in the isothermal zone of a quartz reaction tube. The temperature was set at 350-550 °C, the pressure at 0.1 MPa, and the reactant gas was a mixture of 72% H2 / 18% CO2 / 10% N2 with a flow rate of 50 mL / min and a corresponding volume hourly space velocity (GHSV) of 60000 mL·g. -1 ·h -1 Initiate the catalytic CO2 hydrogenation reaction.

[0133] Gas chromatography was used to detect the content of various substances after the reaction, and the conversion rate of CO2 and product selectivity were calculated.

[0134] Figure 1 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 20 at different temperatures.

[0135] Depend on Figure 1 It can be seen that the S-modified catalyst exhibits high selectivity in catalyzing the hydrogenation of CO2 to CO throughout the entire test temperature range.

[0136] Example 21

[0137] Example 21(a): Performance evaluation of catalytic CO2 hydrogenation reaction

[0138] The operation method is basically the same as that of Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst (2% Ru / Rutile-SO (550°C)) prepared in Example 2. Example 21(b): Performance evaluation of catalytic CO2 hydrogenation reaction

[0139] The operation method is basically the same as that of Example 21(a), except that the composition of the reaction raw gas in Example 21(a) is adjusted to a mixture of 45% H2 / 45% CO2 / 10% N2.

[0140] Example 21(c): Performance evaluation of catalytic CO2 hydrogenation reaction

[0141] The operation method is basically the same as that of Example 21(a), except that the composition of the reaction raw gas in Example 21(a) is adjusted to a mixture of 80% H2 / 10% CO2 / 10% N2.

[0142] Example 21(d): Stability evaluation of the catalyst

[0143] The CO2 hydrogenation performance of the Ru-based catalyst (2% Ru / Rutile-SO (550°C)) prepared in Example 2 was evaluated according to the operation method of Example 21(a), except that the Ru-based catalyst was tested for a long time at high temperatures of 450°C and 550°C to test the high temperature stability of the catalyst. Figure 2 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 21(a) at different temperatures.

[0144] Figure 3 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 21(b) at different temperatures.

[0145] Figure 4 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 21(c) at different temperatures.

[0146] Figure 5 The graph shows the results of the CO2 catalytic hydrogenation stability test of the catalyst in Example 21(d) at different temperatures.

[0147] Depend on Figures 2-4 It can be seen that the 2% Ru / Rutile-SO (550℃) catalyst can generate CO with high activity and high selectivity under different H2 / CO2 ratios, indicating that the catalyst has good applicability. Even when the H2 / CO2 ratio is as high as 8 / 1, it can still achieve high selectivity for the target product CO. At the same time, under the same reaction conditions, the 2% Ru / Rutile-SO (550℃) catalyst has higher catalytic activity than the 2% Ru / Rutile-S catalyst, indicating that precise control of the S content on the catalyst surface by calcination in an air atmosphere helps to improve its catalytic activity for CO2 hydrogenation.

[0148] Depend on Figure 5 It can be seen that the 2% Ru / Rutile-SO (550℃) catalyst did not show a significant decrease in CO2 catalytic hydrogenation activity and CO selectivity after running at 450℃ and 550℃ for 50 hours, indicating that the S-modified catalyst has excellent high-temperature stability.

[0149] Example 22

[0150] Performance evaluation of catalytic CO2 hydrogenation reaction

[0151] The operation method is basically the same as that in Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst (2% Ru / Rutile-SO (650°C)) prepared in Example 3, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0152] Figure 6 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 22 at different temperatures.

[0153] Depend on Figure 6 It can be seen that the 2% Ru / Rutile-S catalyst, after treatment at 650℃ in an oxidizing atmosphere, still maintains the same selectivity for CO2 hydrogenation and still produces CO with high selectivity. This indicates that the S species has a strong interaction with the active metal Ru, and also shows that the S-modified catalyst has excellent high-temperature stability in an oxidizing atmosphere.

[0154] Example 23

[0155] Performance evaluation of catalytic CO2 hydrogenation reaction

[0156] The operation method is basically the same as that in Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst (2% Ru / Rutile-5H2S, 2% Ru / Rutile-100H2S) prepared in Example 4, and the reaction temperature for catalytic CO2 hydrogenation is 450°C.

[0157] Figure 7 The graph shows the performance of the catalyst in Example 23 at 450°C for CO2 catalytic hydrogenation.

[0158] Depend on Figure 7 It can be seen that, under the same reaction conditions, the 2% Ru / Rutile-5H2S catalyst has higher catalytic activity for CO2 hydrogenation than the 2% Ru / Rutile-100H2S catalyst. This indicates that precise control of the content of S species on the surface of the active metal Ru in the catalyst can improve the performance of the catalyst for CO2 hydrogenation and obtain a highly active CO2 hydrogenation catalyst.

[0159] Example 24

[0160] Performance evaluation of catalytic CO2 hydrogenation reaction

[0161] The operation method is basically the same as that in Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst (1% Ru / Rutile-SO (550°C)) prepared in Example 5, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0162] Figure 8 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 24 at different temperatures.

[0163] Example 25

[0164] Performance evaluation of catalytic CO2 hydrogenation reaction

[0165] The operation method is basically the same as that in Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst (10% Ru / Rutile-SO (550°C)) prepared in Example 6, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0166] Figure 9 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 25 at different temperatures.

[0167] Depend on Figures 8-9 It can be seen that S modification can achieve high activity and high selectivity in the catalytic hydrogenation of CO2 to CO by catalysts with different Ru loadings.

[0168] Example 26

[0169] Performance evaluation of catalytic CO2 hydrogenation reaction

[0170] The operation method is basically the same as that in Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst (2% Ru / P25-SO (550°C)) prepared in Example 7, the reaction temperature is 550°C, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0171] Example 27

[0172] Performance evaluation of catalytic CO2 hydrogenation reaction

[0173] The operation method is basically the same as that in Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst (2% Ru / CeO2-SO (550℃)) prepared in Example 8, the reaction temperature is 550℃, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0174] Example 28

[0175] Performance evaluation of catalytic CO2 hydrogenation reaction

[0176] The operation method is basically the same as that in Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst (2% Ru / ZrO2-SO (550℃)) prepared in Example 9, the reaction temperature is 550℃, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0177] Figure 10 The graph shows the CO2 catalytic hydrogenation performance of the catalysts in Examples 26-28 at different temperatures.

[0178] Depend on Figure 10 It is evident that S modification can achieve highly active and selective CO production from CO2 hydrogenation using Ru catalysts supported on different supports. This indicates that the S-based modification method in this invention does not have any dependence on or special requirements for the Ru-based catalyst support, and can achieve highly active and selective CO production from CO2 hydrogenation using Ru catalysts supported on different supports.

[0179] Example 29

[0180] Performance evaluation of catalytic CO2 hydrogenation reaction

[0181] The operation method is basically the same as that in Example 20, except that the catalyst in Example 2 is replaced with the Ru-based catalyst prepared in Example 10, the reaction temperature is 550°C, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0182] Example 30

[0183] Performance evaluation of catalytic CO2 hydrogenation reaction

[0184] The operation method is basically the same as that of Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst prepared in Example 11, the reaction temperature is 550°C, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0185] Example 31

[0186] Performance evaluation of catalytic CO2 hydrogenation reaction

[0187] The operation method is basically the same as that in Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst prepared in Example 12, the reaction temperature is 550°C, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0188] Example 32

[0189] Performance evaluation of catalytic CO2 hydrogenation reaction

[0190] The operation method is basically the same as that in Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst prepared in Example 13, the reaction temperature is 550°C, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0191] Figure 11 The graph shows the CO2 catalytic hydrogenation performance of the catalysts in Examples 29-32 at different temperatures.

[0192] Depend on Figure 11 It can be seen that the 2% Ru / Rutile catalysts synthesized using different ruthenium sources, after S modification, can all catalyze CO2 hydrogenation with high activity and high selectivity to produce CO. This indicates that there are no special requirements for the ruthenium source in this invention, and the effects of this invention can be achieved by using conventional ruthenium-containing compounds.

[0193] Example 33

[0194] Performance evaluation of catalytic CO2 hydrogenation reaction

[0195] The operation method is basically the same as that in Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst prepared in Example 14, the reaction temperature is 550°C, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0196] Example 34

[0197] Performance evaluation of catalytic CO2 hydrogenation reaction

[0198] The operation method is basically the same as that in Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst prepared in Example 15, the reaction temperature is 550°C, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0199] Example 35

[0200] Performance evaluation of catalytic CO2 hydrogenation reaction

[0201] The operation method is basically the same as that in Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst prepared in Example 16, the reaction temperature is 550°C, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0202] Example 36

[0203] Performance evaluation of catalytic CO2 hydrogenation reaction

[0204] The operation method is basically the same as that in Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst prepared in Example 17, the reaction temperature is 550°C, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0205] Figure 12 The graph shows the CO2 catalytic hydrogenation performance of the catalysts in Examples 33-36 at different temperatures.

[0206] Depend on Figure 12 It can be seen that by treating the 2% Ru / Rutile catalyst with different sulfur sources, the resulting catalysts can all achieve high activity and high selectivity in catalytic CO2 hydrogenation to CO, indicating that S treatment does not have special requirements for the sulfur source in modifying the 2% Ru / Rutile catalyst.

[0207] Example 37

[0208] Performance evaluation of catalytic CO2 hydrogenation reaction

[0209] The operation method is basically the same as that in Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst prepared in Example 18, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0210] Figure 13 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 37 at different temperatures.

[0211] Depend on Figure 13 It can be seen that the 2% Ru / Rutile catalyst, after being reduced at high temperature and then modified with S, still exhibits high selectivity in catalyzing the hydrogenation of CO2 to produce CO, indicating that the S modification is not sensitive to the chemical state of the active metal Ru.

[0212] Example 38

[0213] Performance evaluation of catalytic CO2 hydrogenation reaction

[0214] The operation method is basically the same as that in Example 20, except that the catalyst in Example 20 is replaced with the Ru-based catalyst prepared in Example 19, and the composition of the reaction feed gas is adjusted to a mixture of 72% H2 / 18% CO2 / 10% N2.

[0215] Figure 14 The graph shows the CO2 catalytic hydrogenation performance of the catalyst in Example 38 at different temperatures.

[0216] Depend on Figure 14It can be seen that the 2% Ru / Rutile catalyst, after being reduced at high temperature, modified with S, and treated with a high-temperature air atmosphere, still exhibits high selectivity in the catalytic hydrogenation of CO2 to produce CO, indicating that the catalyst has excellent high-temperature stability under an oxidizing atmosphere.

[0217] Example 39

[0218] Stability evaluation of catalysts

[0219] The operation method is basically the same as in Example 20, except that the catalyst in Example 20 is replaced with a 2% Ru / Rutile catalyst, and the composition of the reactant gas is adjusted to a mixture of 50 mL / min 72% H2 / 18% CO2 / 10% N2 and co-fed with a mixture of 2 mL / min 0.5% H2S / Ar. The catalyst performance is evaluated at a reaction temperature of 550°C, and the results are as follows. Figure 15 As shown.

[0220] Depend on Figure 15 It can be seen that the 2% Ru / Rutile catalyst can achieve in-situ S modification under an S reaction atmosphere. It can catalyze the hydrogenation of CO2 to CO with high selectivity and can maintain its catalytic performance for a long time. This indicates that the catalyst has the ability to catalyze the conversion of sulfur-containing CO2 atmosphere and industrial sulfur-containing CO2 tail gas.

[0221] Example 40

[0222] The Ru-based catalyst (2% Ru / Rutile-SO (550℃)) prepared in Example 2 was evaluated for its catalytic performance in CO2 hydrogenation at 450℃ in a fixed-bed reactor. The catalyst performance evaluation was carried out in a fixed-bed reactor equipped with a quartz reaction tube with an inner diameter of 8 mm. The specific steps are as follows:

[0223] The Ru-based catalyst synthesized in Example 2 was sequentially pressed into tablets and sieved to prepare Ru-based catalyst powder with a particle size of 20-40 mesh. 50 mg of Ru-based catalyst powder was weighed and mixed evenly with 450 mg of quartz sand (particle size 20-40 mesh). The Ru-based catalyst mixed with quartz sand was sandwiched in the isothermal zone of a quartz reaction tube. The temperature was set at 450°C, the pressure at 0.1 MPa, and the reactant gas was a mixture of 60% H2 / 15% CO2 / 15% CO / 10% N2 (simulating the catalytic conversion of the reaction tail gas under CO2 reaction conditions to test the catalyst's tail gas circulation catalytic performance). The flow rate of the reactant gas was 50 mL / min, corresponding to a volume hourly space velocity (GHSV) of 60000 mL·g. -1 ·h -1 Initiate the catalytic CO2 hydrogenation reaction.

[0224] Gas chromatography was used to detect the content of various substances after the reaction, and the conversion rate of CO2 and product selectivity were calculated.

[0225] Figure 16 The figure shows the catalytic hydrogenation performance of the catalyst in Example 40 on the tail gas of the simulated cyclic CO2 hydrogenation reaction.

[0226] Depend on Figure 16 It can be seen that when the feed gas of 2% Ru / Rutile-SO (550℃) is 60% H2 / 15% CO2 / 15% CO / 10% N2, the CO selectivity of the product is still as high as 98%, indicating that the catalyst has the potential to realize the recycling conversion of CO2 catalytic hydrogenation tail gas and can achieve efficient conversion and utilization of CO2.

[0227] Comparative Example 1

[0228] Weigh 60.0 mg RuCl3·xH2O and mix with 5 mL of deionized water. Under stirring, the RuCl3·xH2O is fully dispersed in the water to form a uniform dispersion. Weigh 1 g of Rutile powder carrier and place it in the dispersion. Under water bath conditions, heat the resulting liquid to 40°C and stir continuously to completely evaporate the water. Collect the solid material.

[0229] The solid material was placed in an oven and dried overnight at 110°C. After the dried solid material was ground for 10 minutes, it was placed on a ceramic boat and placed in a muffle furnace and calcined at 500°C for 3 hours. After calcination, the precursor was obtained.

[0230] The precursor was placed in a tube furnace and reduced at 550°C for 1 h in an H2 / Ar mixed atmosphere (H2 volume fraction of 20%) to obtain a Ru-based catalyst, denoted as 2%Ru / Rutile-H2.

[0231] Comparative Example 2

[0232] Comparative Example 2(a): Performance Evaluation of Catalytic CO2 Hydrogenation Reaction

[0233] The Ru-based catalyst (2% Ru / Rutile-H2) prepared in Comparative Example 1 was evaluated for its catalytic performance in CO2 hydrogenation in a fixed-bed reactor. The catalyst performance evaluation was conducted in a fixed-bed reactor equipped with a quartz reaction tube with an inner diameter of 8 mm. The specific steps were as follows:

[0234] The Ru-based catalyst synthesized in Comparative Example 1 was sequentially compressed and sieved to prepare Ru-based catalyst powder with a particle size of 20-40 mesh. 50 mg of Ru-based catalyst powder was weighed and mixed evenly with 450 mg of quartz sand (particle size of 20-40 mesh). The Ru-based catalyst mixed with quartz sand was sandwiched in the isothermal zone of a quartz reaction tube. The temperature was set at 350-550℃, the pressure at 0.1 MPa, and the reactant gas was a mixture of 72% H2 / 18% CO2 / 10% N2 with a flow rate of 50 mL / min and a corresponding volume hourly space velocity (GHSV) of 60000 mL·g. -1 ·h -1 Initiate the catalytic CO2 hydrogenation reaction.

[0235] Gas chromatography was used to detect the content of various substances after the reaction, and the conversion rate of CO2 and product selectivity were calculated.

[0236] Figure 17 The figure shows the CO2 catalytic hydrogenation performance of the catalyst in Comparative Example 2(a) at different temperatures.

[0237] Depend on Figure 17 It can be seen that the 2% Ru / Rutile catalyst mainly produces CH4 during the hydrogenation of CO2 throughout the entire test temperature range. At 550℃, the CO selectivity is only 29.9%, indicating that the 2% Ru / Rutile catalyst is a typical methanation catalyst.

[0238] Comparative Example 2(b): Performance Evaluation of the Catalyst

[0239] The CO2 hydrogenation performance of the Ru-based catalyst (2% Ru / Rutile-H2) prepared in Comparative Example 1 was evaluated according to the procedure in Comparative Example 2(a), with the only difference being that the Ru-based catalyst was subjected to a long-term test at 550℃ to test its high-temperature stability. The results are as follows. Figure 18 As shown.

[0240] Depend on Figure 18 It can be seen that the CO selectivity of the 2% Ru / Rutile catalyst remained at around 29.5% after operating at 550℃ for 60 hours, indicating that even at 550℃, the 2% Ru / Rutile catalyst still mainly produces CH4 during the hydrogenation of CO2.

[0241] Comparative Example 3

[0242] Performance evaluation of catalytic CO hydrogenation reaction

[0243] The operation method is basically the same as that of Comparative Example 2(a), except that the catalyst in Comparative Example 2(a) is replaced with the catalyst in Example 21, and the composition of the reaction feed gas is adjusted to a mixture of 60% H2 / 20% CO / 20% N2.

[0244] Figure 19 The graph shows the CO catalytic hydrogenation performance of the catalyst in Comparative Example 3 at different temperatures.

[0245] Depend on Figure 19 It is known that the 2% Ru / Rutile catalyst has high CO hydrogenation activity, therefore the CO generated by it is prone to further hydrogenation to form CH4.

[0246] Comparative Example 4

[0247] The operation method is basically the same as that of Comparative Example 2(a), except that the composition of the reaction raw gas in Comparative Example 2(a) is adjusted to a mixture of 60% H2 / 20% CO / 20% N2.

[0248] Figure 20 The graph shows the CO catalytic hydrogenation performance of the catalyst in Comparative Example 4 at different temperatures.

[0249] Depend on Figure 20 It is known that the 2% Ru / Rutile-SO (550℃) catalyst has extremely low activity in the catalytic hydrogenation of CO. Therefore, the CO generated by the catalytic hydrogenation of CO2 by the 2% Ru / Rutile-SO (550℃) catalyst cannot undergo further deep hydrogenation to generate CH4, and it has high CO selectivity.

[0250] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a ruthenium-based catalyst, comprising the following steps: A ruthenium source is mixed with a support and calcined to obtain a precursor; the support includes at least one of a metal oxide support, a carbon material support, a boron nitride support, and a silicon carbide support; the metal oxide support includes at least one of a titanium dioxide support, a cerium dioxide support, and a zirconium dioxide support. The precursor was mixed with a sulfur source and modified by calcination or a multi-pulse atomic layer deposition strategy to obtain the ruthenium-based catalyst. The ruthenium-based catalyst comprises a support and an active substance Ru and a sulfur species supported on the support; the loading of the active substance Ru is 1~15 wt%; and the loading of the sulfur species is 0.001~1 wt%.

2. The preparation method according to claim 1, characterized in that, The ruthenium source includes at least one of ruthenium chloride, ruthenium chloride hydrate, ruthenium acetate, ruthenium nitrate, ruthenium acetylacetone, and ruthenium bromide.

3. The preparation method according to claim 1, characterized in that, The sulfur source includes at least one of elemental sulfur, potassium sulfide, hydrogen sulfide, sulfur dioxide, thiols, benzenesulfonic acid, and thioethers.

4. The preparation method according to claim 1, characterized in that, The roasting temperature is 350~800℃, and the holding time is 1~24h.

5. The preparation method according to claim 1 or 3, characterized in that, When the sulfur source is non-gaseous, the modification treatment is calcination; the calcination temperature is 150~700℃, and the holding time is 0.1~24h; the molar ratio of ruthenium in the ruthenium source to sulfur in the sulfur source is 0.1~200:1; When the sulfur source is gaseous, the modification treatment is a calcination or atomic layer deposition multi-pulse strategy, and the modification treatment is carried out in a sulfur-containing atmosphere; When the modification treatment is calcination, the volume fraction of sulfur source in the sulfur-containing atmosphere is 0.01%~100%; the calcination temperature is 150~600℃, and the holding time is 0.001~24h. When the modification treatment is an atomic layer deposition (ALD) multi-pulse strategy, the volume fraction of sulfur source in the sulfur-containing atmosphere is 0.1-10%; the operating temperature of the ALD multi-pulse strategy is 100-550℃; the single pulse time of the sulfur-containing atmosphere is 0.1-3s, and the number of pulse cycles is 1-3000; nitrogen is used as a carrier during the pulse process of the ALD multi-pulse strategy, and the flow rate of the nitrogen is 30-150mL / min.

6. The preparation method according to claim 5, characterized in that, The modification process includes: reducing the precursor in an H2 atmosphere; the volume fraction of H2 in the H2 atmosphere is 1% to 100%; the temperature of the reduction process is 250 to 800°C, and the holding time is 0.3 to 24 hours.

7. The preparation method according to claim 6, characterized in that, The modification process further includes: subjecting the obtained modified material to heat treatment; the heat treatment temperature is 300~750℃, and the holding time is 1~72h.

8. The ruthenium-based catalyst prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the ruthenium-based catalyst according to claim 8 in the catalytic hydrogenation of CO2 to CO reaction.

10. The application according to claim 9, characterized in that, The reactant gas for the catalytic CO2 hydrogenation to CO reaction includes H2, CO2 and N2; the volume ratio of H2, CO2 and N2 in the reactant gas is 45~80:10~45:10~20; the temperature of the catalytic CO2 hydrogenation to CO reaction is 350~750℃ and the pressure is 0.1MPa.

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