Cu / Z bifunctional material, preparation method thereof and application of Cu / Z bifunctional material in carbon dioxide reduction

Abstract

The invention relates to a Cu / Z bifunctional material, a preparation method thereof and application of the Cu / Z bifunctional material in carbon dioxide reduction, and belongs to the field of carbon dioxide treatment. The method comprises the following steps: fully mixing a Cu source and an M source at a water bath temperature of 40-90 DEG C, titrating the pH value of the solution to 5-11 by using a precipitant, and washing the obtained precipitate to be neutral through centrifugation or suction filtration and other steps to obtain a precursor; calcining the precursor at the temperature of 250 DEG C or above to obtain a precursor material; and carrying out thermal modification on the precursor material in a hydrogen-containing atmosphere to prepare the Cu / Z bifunctional material, the Z source is a raw material capable of providing at least one metal of cerium, zinc, gallium, zirconium, indium and aluminum, the proportion of the Cu source is 20-60%, and the precipitator is an alkaline or other property material capable of promoting generation of Cu precipitation. The invention also comprises the material prepared by the preparation method and application of the material in carbon dioxide capture and conversion. The material prepared by the preparation method disclosed by the invention has excellent carbon dioxide reduction catalytic activity.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial process waste gas purification, and specifically relates to the technical field of carbon dioxide catalytic degradation. Background Art

[0002] Conventional CCUS full-process technology covers the four links of carbon dioxide capture, transportation, utilization, and storage. However, CCUS projects are currently facing severe problems such as high energy consumption, high cost, and poor emission reduction effects, and the overall project is in a negative return state. ICCU (Integrated Carbon Capture and Utilization) technology eliminates the process of enriching, compressing, and transporting CO2 while achieving high-value utilization of CO2, and has the characteristics of low cost and high efficiency. Among various CO2 utilization pathways, the catalytic hydrogenation of CO2 to methanol through ICCU has attracted widespread attention, mainly due to the following advantages. First, the operating temperature of methanol synthesis is relatively low (200-300°C), while other CO2 conversion processes, such as methanation or reverse water gas shift reaction, usually require temperatures above 400°C. Lower operating temperatures are beneficial to the ICCU process because it is better compatible with the CO2 capture step and reduces energy consumption. Secondly, methanol is a high-value-added product that is widely used in fuels, solvents, and chemical raw materials. Third, methanol is a liquid at room temperature and pressure, making it easier to store, transport and distribute than gaseous products such as methane or carbon monoxide. This easy handling feature is particularly advantageous for decentralized methanol production from CO2-captured emission sources.

[0003] In the existing methanol synthesis catalytic system, metal catalysts (such as platinum, palladium [1,2] etc.) are widely used due to their excellent catalytic performance. [3-5] As a representative non-precious metal catalyst, Fe [6] ,nickel [7] MoS2 with transition metals and sulfur vacancies [8] etc., have been applied to the research of gas-phase CO2 hydrogenation to methanol. However, the development of efficient and stable CO2 hydrogenation catalysts remains challenging, mainly due to the required high temperatures, limited reactivity and poor selectivity. Therefore, it is necessary to develop new methanol production pathways or reaction systems to solve the bottleneck problems in the existing technology.

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[0005] [2]García-Trenco A,White E R,Regoutz A,et al.Pd2Ga-Based Colloids asHighly Active Catalysts for the Hydrogenation of CO2 to Methanol[J].ACSCatalysis,2017,7(2):1186-96.

[0006] [3]Zhao H,Yu R,Ma S,et al.The role of Cu1–O3 species in single-atomCu / ZrO2 catalyst for CO2 hydrogenation[J].Nature Catalysis,2022,5(9):818-31.

[0007] [4]Wu C,Lin L,Liu J,et al.Inverse ZrO(2) / Cu as a highly efficientmethanol synthesis catalyst from CO(2)hydrogenation[J].Nat Commun,2020,11(1):5767.

[0008] [5]Wang Y,Kattel S,Gao W,et al.Exploring the ternary interactions inCu-ZnO-ZrO(2)catalysts for efficient CO(2)hydrogenation to methanol[J].NatCommun,2019,10(1):1166.

[0009] [6]Li A,Pu Y,Li F,et al.Synthesis of dimethyl carbonate from methanoland CO 2over Fe–Zr mixed oxides[J].Journal of CO2 Utilization,2017,19:33-9.

[0010] [7]Gallo A,Snider JL,Sokaras D,et al.Ni5Ga3 catalysts for CO2reduction to methanol:Exploring the role of Ga surface oxidation / reduction oncatalytic activity[J].Applied Catalysis B:Environmental,2020,267.

[0011] [8]Hu J, Yu L, Deng J, et al. Sulfur vacancy-rich MoS2 as a catalyst for the hydrogenation of CO2 to methanol[J]. Nature Catalysis, 2021, 4(3): 242-50. Summary of the invention

[0012] In view of the problem that the existing carbon dioxide capture and hydrogenation to methanol have unsatisfactory effects, the first purpose of the present invention is to provide a method for preparing a Cu / Z bifunctional material (also known as a carbon dioxide capture and reduction catalyst) to obtain a catalyst with excellent carbon dioxide capture and reduction activity.

[0013] The second purpose of the present invention is to provide a Cu / Z dual-functional material obtained by the preparation method.

[0014] The third object of the present invention is to provide a method for carbon dioxide capture and reduction using the Cu / Z dual-functional material, aiming to improve carbon dioxide capture and reduction activity to produce methanol.

[0015] A preparation method of a Cu / Z dual-functional material comprises dissolving a Cu source and a Z source in deionized water, mixing them uniformly under a water bath temperature of 40-90° C., using a precipitant to control the pH value of the solution to 5-11, washing the obtained precipitate with water until it is neutral to obtain a precursor; calcining the precursor at a temperature above 250° C. to obtain a precursor material; and thermally modifying the precursor material in a hydrogen-containing atmosphere to obtain the Cu / Z dual-functional material.

[0016] The Z source is a raw material that can provide at least one metal among cerium, zinc, gallium, zirconium, indium and aluminum, and the weight content of Cu is 20-60%.

[0017] The present invention pre-calcines the Cu-containing precursor at the temperature and then thermally modifies it in a hydrogen-containing atmosphere, thereby improving the crystal distance and other physicochemical structural characteristics of the prepared material, thereby making it suitable for carbon dioxide capture and reduction catalysis requirements and improving the carbon dioxide capture and reduction catalysis effects.

[0018] In the present invention, the Cu source is any component that can provide Cu material, for example, it can be at least one of copper oxide, carbonate, bicarbonate, nitrate, and organic acid salt;

[0019] In the present invention, the Z source is at least one of an oxide, carbonate, bicarbonate, nitrate, and organic acid salt of the Z metal;

[0020] Preferably, Z is a combination of zinc and gallium. Studies have shown that the use of the combination Z can unexpectedly further cooperate with the process, help to further jointly control the interaction mode structure of the product, so that it exhibits better carbon dioxide capture and reduction activity.

[0021] In the present invention, when Z is a combination of zinc and gallium, there is no particular requirement for the ratio of the two. For example, the ratio of zinc to gallium can be 15:0.5-1.

[0022] In the present invention, the precipitant includes but is not limited to at least one of sodium carbonate, sodium hydroxide, sodium bicarbonate, ammonia water, ammonium carbonate and oxalic acid;

[0023] Preferably, the pH of the solution is controlled to be 5-11 using a precipitant, and further to be 7-9;

[0024] In the present invention, the solvent in the pre-reaction stage is water, or a mixed solvent of water-organic solvent;

[0025] Preferably, the temperature of the pre-reaction (also called coprecipitation reaction) is 40-90°C.

[0026] In the present invention, the precipitate is washed to neutrality by, for example, centrifugation or suction filtration, and washed with deionized water.

[0027] In the present invention, the precursor is innovatively calcined, combined with a subsequent thermal modification treatment in a hydrogen-containing atmosphere, which can unexpectedly adjust the physical phase and crystal spacing of the product, thereby making it suitable for carbon dioxide capture and reduction catalysis requirements, and can significantly improve the efficiency and effect of the catalytic reduction of carbon dioxide to methanol.

[0028] In the present invention, the atmosphere in the calcination stage is an oxygen-containing atmosphere, which can be oxygen, or a mixture of oxygen and other gases (such as nitrogen, argon, etc.). Considering the simplicity and cost of the processing process, it can further be air;

[0029] In the present invention, the calcination temperature is 250-600° C., more preferably 300-400° C. In the present invention, the product phase and crystal distance can be regulated at such a relatively low temperature, thereby making it more suitable for the application requirements of carbon dioxide capture and reduction.

[0030] In the present invention, the holding time at the calcination temperature is 3 to 8 hours, and can further be 4 to 5 hours.

[0031] In the present invention, the content of the gas in the hydrogen-containing atmosphere is 20-100v%, and the pressure used is 1-60bar;

[0032] Preferably, the temperature in the thermal modification stage is 200 to 500°C, more preferably 300 to 400°C;

[0033] Preferably, the holding time at the thermal modification temperature is 1 to 4 hours.

[0034] The invention also provides a Cu / Z dual-functional material prepared by the preparation method.

[0035] The preparation method described in the present invention can give the material special physical phases and characteristics such as crystals and grain boundaries, and the material with the characteristics obtained by the preparation method can unexpectedly adapt to the requirements of carbon dioxide capture and reduction catalysis, and can significantly improve the yield of carbon monoxide.

[0036] The present invention also provides a method for resource utilization of waste gas containing carbon dioxide, using the Cu / Z dual-functional material of the present invention to capture carbon dioxide in the waste gas containing carbon dioxide, then reducing it in a hydrogen-containing atmosphere under a certain pressure, and collecting the methanol product in the reduction stage.

[0037] In the present invention, the waste gas containing carbon dioxide can be any gas that has a need for carbon dioxide recovery. For example, the waste gas containing carbon dioxide has a carbon dioxide content of 5-30%, and nitrogen oxides <500mg / m3 , sulfur dioxide <1000mg / m 3 , particulate matter <100mg / m 3 .

[0038] In the present invention, the carbon dioxide capture temperature is 25-500°C and the pressure used is 1-60 bar.

[0039] In the present invention, during the reduction stage, the hydrogen content of the hydrogen atmosphere is 30-100v%, the pressure is 1-60bar, and the temperature is 200-500°C, further 220-400°C, and further 260-340°C.

[0040] In the present invention, before capture, the Cu / Z bifunctional material is activated in advance with a hydrogen-containing atmosphere, and then capture and subsequent reduction treatment are performed; in the present invention, before carbon dioxide capture-reduction, it can be preferably activated in advance with a hydrogen-containing atmosphere. The activation temperature can be optionally 200-500°C (further 220-400°C), the pressure can be 1-60bar (further 20-40bar), and the time can be optionally 0.1-2h (further 0.5-1.5h).

[0041] In the present invention, the Cu / Z material prepared by the preparation method has excellent catalytic reduction activity, and also has excellent structural stability and regeneration ability, and can be used for cyclic capture and reduction treatment to achieve cyclic capture and reduction of carbon dioxide.

[0042] Beneficial Effects

[0043] The present invention pre-calcines the Cu-containing precursor at the temperature and then thermally modifies it in a hydrogen-containing atmosphere, which can unexpectedly improve the interaction mode and other physicochemical structural characteristics of the prepared material, thereby improving the activity of carbon dioxide capture and reduction to methanol.

[0044] In the present invention, under the preferred process, the crystal characteristics of the product can be further optimized to make it more suitable for the application requirements of carbon dioxide capture and reduction.

[0045] Studies have shown that the Cu / Z bifunctional material of the present invention has good stability in the adsorption calcination cycle and can achieve a methanol yield of 0.61 mmol g -1 h -1 The methanol yield of the first cycle material was 0.45 mmol g after three cycles of experiments at 300 °C and 30 bar for more than 20 hours. -1 h -1 After three cycles of reaction, the yield remained at 0.44 mmol g-1 h -1 The above advantages make the present invention have excellent technical and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is the XRD pattern of the Cu / Z dual-functional material prepared in Example 1.

[0047] Figure 2 TEM and element scanning images of the Cu / Z dual-functional material prepared in Example 1; DETAILED DESCRIPTION

[0048] The present invention provides a method for preparing a Cu / Z dual-functional material, the steps comprising:

[0049] The first step is to dissolve the Cu source and the Z source in deionized water to form a mixed solution containing metal ions, wherein the Cu element accounts for 20-60% by weight;

[0050] The second step is to heat in a water bath at 40-90°C and stir continuously, slowly drop a precipitant to control the pH value of the solution to 5-11, then wash with water until neutral and dry at 100-120°C to obtain a precursor;

[0051] The third step is to calcine the precursor in an air atmosphere in a muffle furnace at 250-500° C., more preferably 300-400° C., to obtain a precursor material.

[0052] In the fourth step, the precursor material is thermally modified in a hydrogen-containing atmosphere to obtain a Cu / Z composite material.

[0053] <Integrated CO2 Capture and Utilization Method>

[0054] Another object of the present invention is to provide a method for integrating CO2 capture and utilization using the novel Cu / Z dual-functional material of the present invention, characterized in that the novel Cu / Z composite material of the present invention is contacted with industrial flue gas at 25-500°C and a pressure of 1-60 bar to capture the carbon dioxide therein, and then catalytically reduced in a hydrogen-containing atmosphere at a temperature of 200-500°C and a pressure of 1-60 bar to prepare methanol. A further preferred application method of the present invention is to activate the Cu / Z dual-functional material in a hydrogen-containing atmosphere in advance, then mix it with an atmosphere containing carbon dioxide for capture, and then reduce it in a hydrogen-containing atmosphere.

[0055] In the present invention, the carbon dioxide capture and reduction process may be repeated.

[0056] In the present invention, in the laboratory stage, a carbon dioxide-Ar composite gas is used as a test simulation gas.

[0057] Example

[0058] The present invention is further described below with reference to examples, which are only used to explain the present invention and are not used to limit the scope of the present invention. It should be understood that the present invention is not limited to the following specific embodiments, and those skilled in the art can make various modifications or variations within the scope of the claims.

[0059] Example 1

[0060] Step a. Preparation of novel Cu / Zn composite material

[0061] a-1: Copper nitrate (Cu source), gallium nitrate and zinc nitrate as Z sources are mixed in deionized water (Cu element accounts for about 40%), and after being heated in a water bath at 60-80°C and fully stirred, a precipitant sodium carbonate solution (0.5M) is slowly dripped into the above solution to make the solution pH 8, and then centrifuged and washed to the center, and dried in an oven at 100-120°C to obtain a precursor, and then the precursor is calcined in an air atmosphere at 400°C for 4h to obtain a precursor catalyst;

[0062] a-2: The precursor catalyst was placed in a H2 atmosphere (hydrogen pressure was set to 30 bar) and thermally modified at 300°C for 2 h to obtain a Cu / Z dual-functional material. XRD Figure 1 TEM and element scanning images are shown in Figure 2 , showing the separation of Cu and Zn materials, and uniform dispersion of Ga.

[0063] Step b. CO2 capture and conversion performance testing

[0064] A high-pressure fixed-bed reactor was used to test the effect of synthesized Cu / Z bifunctional materials on capturing and utilizing carbon dioxide. The fixed bed controlled temperature range was 200-500°C, and the pressure range was 1-60bar. Before the experiment, 0.06-0.08g of quartz wool was placed in the quartz tube, followed by 0.1g of Cu / Z bifunctional material. The experimental gas conditions were 15% CO2 / Ar, 100% H2 and pure Ar for purging. The gas components were controlled by a mass flow meter, and the total flow rate was controlled to be 100ml / min. After mixing, the gas entered the fixed bed through a pipeline for experiment.

[0065] First, the CO2 / Ar is introduced for 60 minutes (the temperature of the treatment stage is T, the pressure is P, and the temperature T and pressure P are kept at the capture time). After the adsorption is completed, Ar is introduced again for purging. Finally, the H2 / Ar is introduced to realize the carbon dioxide reduction conversion experiment. The H2 introduction time is set to 180 minutes (the temperature of the treatment stage is T, the pressure is P, and the temperature T and pressure P are kept at the reduction conversion time). The cyclic experiment repeats the purging, adsorption and reaction process gas switching. The components and concentrations of the consumed and generated gases during the experiment are jointly determined by an online process mass spectrometer (MS) and a gas chromatograph (GC). The instrument measurement error is linearly calibrated with standard gases of different concentrations, and the error is less than ±3% of the total range. The measured active temperature range is 220-400°C, wherein the methanol yield is 0.45 mmol g when the temperature T is 300°C and the pressure P is 30 bar. -1 h -1 After the first cycle of three cycles lasting more than 20 hours, the methanol yield remained at 0.44 mmol g -1 h -1 The temperature T is 300 °C, the pressure is 40 bar, and the methanol yield is 0.61 mmol g -1 h -1 , temperature T is 300 °C, pressure is 20 bar, methanol yield is 0.12 mmol g -1 h -1 , temperature T is 260℃, pressure is 30bar, methanol yield is 0.11mmol g -1 h -1 , temperature T is 340℃, pressure is 30bar, methanol yield is 0.11mmol g -1 h -1 .

[0066] Example 2

[0067] Compared with Example 1, the only difference is that the type of Z source is changed, wherein the proportion of Cu element is the same as that of Example 1, and the experimental groups are:

[0068] Group A: Z source is gallium nitrate;

[0069] Group B: Z source is zinc nitrate;

[0070] The test was carried out according to the method described in Example 1, and the results were:

[0071] Group A: The temperature range is 260-340°C and the pressure is 20-40 bar. The methanol production is 0.23 mmol g at 300°C and 30 bar. -1 h -1 .

[0072] Group B: The temperature range is 260-340°C and the pressure is 20-40 bar. The methanol production is 0.32 mmol g at 300°C and 30 bar. -1 h -1 .

[0073] By comparing Example 1 with Examples 2A and 2B, it can be seen that by using the combination of Z and Cu in conjunction with the preparation process, excellent carbon dioxide capture and conversion capabilities can be obtained, especially when Zn and Ga are used as the Z source, a better synergistic effect can be unexpectedly obtained.

[0074] Example 3

[0075] Compared with Example 1, the only difference is that the dosage of Cu source and Z source remains unchanged, the pH value of the solution is titrated to 6 using a precipitant sodium carbonate during the preparation process, and the other operations and parameters are the same as in Example 1:

[0076] The test was carried out according to the method described in Example 1. The results were as follows: the methanol production was 0.34 mmol g at a temperature of 300 °C and a pressure of 30 bar. -1 h -1 .

[0077] Example 4

[0078] Compared with Example 1, the only difference is that sodium hydroxide is used as the precipitant, and the other operations and parameters are the same as those in Example 1:

[0079] The test was carried out according to the method described in Example 1. The results were as follows: the methanol production was 0.40 mmol g at a temperature of 300 °C and a pressure of 30 bar. -1 h -1 .

[0080] Example 5

[0081] Compared with Example 1, the only difference is that the calcination temperature in step a is changed to 300° C., the time is changed to 4 h, and the hydrogen content in the thermal modification atmosphere is changed to 60 v%. Other operations and parameters are the same as in Example 1.

[0082] The test found that the methanol production was 0.28 mmol g at a temperature of 300 °C and a pressure of 30 bar. -1 h -1 .

[0083] Example 6

[0084] Compared with Example 1, the only difference is that during the CO2 adsorption process, the temperature is lowered to room temperature and the pressure is reduced to 1 bar, followed by 1 hour of adsorption, and then the temperature is raised to 300°C under inert gas, the pressure is raised to 30 bar, and hydrogen is introduced to react for 1 hour after stabilization. Other operations and parameters are the same as in Example 1.

[0085] The test found that after this operation, the methanol production was 0.03mmol g -1 h -1 .

[0086] Example 7

[0087] Compared with Example 1, the only difference is that in step (b), after the CO2 / Ar capture and purging is completed, 40v% hydrogen-Ar atmosphere is introduced into the system, and other operations and parameters are the same as Example 1.

[0088] The test was carried out according to the method described in Example 1. The results were as follows: the methanol production was 0.16 mmol g at a temperature of 300 °C and a pressure of 30 bar. -1 h -1 .

Claims

1. A method for preparing a Cu / Z dual-functional material, characterized in that: Dissolve the Cu source and the M source in deionized water, fully stir at a water bath temperature of 40-90°C, gradually drop a precipitant into the solution to make the pH value of the solution 5-11, wash with deionized water to neutrality after obtaining a precipitate, and obtain a precursor; calcine the precursor at a temperature above 250°C to obtain a precursor material; and then thermally modify the precursor material in a hydrogen-containing atmosphere to obtain the Cu / Z dual-functional material; The Z source is a raw material that can provide at least one metal among cerium, zinc, gallium, zirconium, indium and aluminum, and the weight content of Cu is 20-60%.

2. The method for preparing the Cu / Z dual-functional material according to claim 1, characterized in that: The Cu source is at least one of copper oxide, carbonate, bicarbonate, nitrate and organic acid salt; Preferably, the Z source is at least one of an oxide, carbonate, bicarbonate, nitrate, and organic acid salt of the Z metal; Preferably, Z is a combination of zinc and gallium; Preferably, the precipitant includes but is not limited to at least one of sodium carbonate, sodium hydroxide, sodium bicarbonate, ammonia water, ammonium carbonate, and oxalic acid; Preferably, the reaction pH value is 5-11, and can further be 7-9; Preferably, the solvent in the pre-reaction stage is water, or a mixed solvent of water-organic solvent; Preferably, the temperature of the pre-reaction is 40-90°C.

3. The method for preparing the Cu / Z dual-functional material according to claim 1, characterized in that: The atmosphere during the calcination stage is an oxygen-containing atmosphere, preferably air; Preferably, the calcination temperature is 250-600°C, more preferably 300-400°C; Preferably, the holding time at the calcination temperature is 3 to 8 hours, preferably 4 to 5 hours.

4. The method for preparing the Cu / Z dual-functional material according to claim 1, characterized in that: The content of the gas in the hydrogen-containing atmosphere is 20-100V%, and the pressure used is 1-60bar; Preferably, the temperature in the thermal modification stage is 200 to 500°C, more preferably 300 to 400°C; Preferably, the holding time at the thermal modification temperature is 1 to 4 hours.

5. A Cu / Z dual-functional material obtained by the preparation method according to any one of claims 1 to 4.

6. A method for resource utilization of waste gas containing carbon dioxide, characterized in that: The Ca / M composite material described in claim 5 is used to capture carbon dioxide in the waste gas containing carbon dioxide, and then reduction treatment is carried out in a hydrogen-containing atmosphere to collect the methanol product in the reduction stage.

7. The method for resource utilization of waste gas containing carbon dioxide according to claim 6, characterized in that: The carbon dioxide content in the carbon dioxide-containing waste gas is 5-30%, and the nitrogen oxide content is <500mg / m 3 , sulfur dioxide <1000mg / m 3 , particulate matter <100mg / m 3 .

8. The method for resource utilization of waste gas containing carbon dioxide according to claim 6, characterized in that: The carbon dioxide capture temperature is 25-500°C and the pressure used is 1-60 bar.

9. The method for resource utilization of waste gas containing carbon dioxide according to claim 6, characterized in that: In the reduction stage, the hydrogen content of the hydrogen atmosphere is 30-100v%, the temperature is 200-500°C, and the pressure is 1-60bar.

10. The resource utilization method of waste gas containing carbon dioxide according to any one of claims 6 to 9, characterized in that: Before capture, the Cu / Z bifunctional material is activated in advance using a hydrogen-containing atmosphere, followed by capture and subsequent reduction treatment; Preferably, the capture and reduction processes are performed cyclically.

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