Flue gas absorption-based multi-metal supported calcium carbonate catalyst capable of being prepared in batches as well as preparation method and application of flue gas absorption-based multi-metal supported calcium carbonate catalyst

Abstract

The invention relates to the technical field of heterogeneous catalysis and electro-catalysis, in particular to a multi-metal supported calcium carbonate catalyst based on flue gas absorption and capable of being prepared in batches and a preparation method and application thereof. The method comprises the following steps: S1) blowing flue gas into a lime milk solution, stirring, stopping introducing gas when turbid liquid is neutral, settling the turbid liquid, decanting an upper-layer solution, and drying a lower-layer solid to obtain a calcium carbonate solid; and S2) mixing the calcium carbonate solid with a solution of metal chloride, standing, decanting an upper-layer solution after the turbid liquid is settled and layered, and drying a lower-layer solid to obtain the multi-metal loaded calcium carbonate catalyst. According to the method, the multi-metal loaded calcium carbonate catalyst can be obtained through a simple bubbling method and stirring, is not influenced by flue gas components, can be amplified to a kilogram level, and lays a foundation for subsequent amplification experiments of the catalyst. The catalyst is used for large-scale carbon dioxide electrolysis, and synthesis gas, pure formic acid and multi-carbon products can be efficiently obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of heterogeneous catalysis and electrocatalysis, and in particular to a multi-metal supported calcium carbonate catalyst which can be prepared in batches based on flue gas absorption, and a preparation method and application thereof. Background Art

[0002] Fossil energy is the main energy source for today's social development and human production and life. Carbon dioxide is emitted into the atmosphere as the final product of fossil energy use. Excessive carbon dioxide emissions will lead to many environmental problems such as ocean acidification and greenhouse effect, posing a huge threat to the sustainable development of human society. Using electrocatalytic methods to convert carbon dioxide and water into valuable products such as synthesis gas, formic acid, and multi-carbon is considered to be a very promising way to convert and utilize carbon dioxide. Summary of the invention

[0003] In view of this, the technical problem to be solved by the present invention is to provide a multi-metal supported calcium carbonate catalyst that can be prepared in batches based on flue gas absorption, and a preparation method and application thereof, wherein the catalyst can be used for large-scale carbon dioxide electrolysis.

[0004] To achieve the above object, the present invention provides a method for batch preparation of a multi-metal supported calcium carbonate catalyst based on flue gas absorption, comprising the following steps:

[0005] S1) blowing flue gas into the lime milk solution and stirring, when the suspension is neutral, stopping the ventilation, settling the suspension, decanting the upper solution, and drying the lower solid to obtain calcium carbonate solid;

[0006] S2) The calcium carbonate solid and the metal chloride solution are mixed and allowed to stand for precipitating and stratifying. The upper layer of the solution is decanted and the lower layer of the solid is dried to obtain a multi-metal supported calcium carbonate catalyst.

[0007] The present invention has no particular limitation on the source of the flue gas, which may be flue gas generated by the cement industry or flue gas generated by combustion. The components of the flue gas preferably include carbon dioxide.

[0008] Optionally, based on different sources, the flue gas may also include one or more of nitrogen, oxygen, carbon monoxide, sulfur dioxide, nitrogen oxides and dust. The test results show that the above components have no effect on the formation and performance of the catalyst.

[0009] The present invention has no particular limitation on the above-mentioned lime milk solution, and it can be prepared according to methods well known to those skilled in the art. Preferably, calcium oxide is digested in tap water at a certain ratio to obtain lime milk.

[0010] The concentration of the lime milk solution is preferably 0.001 to 10 kg / L, more preferably 0.01 to 1 kg / L, and even more preferably 0.01 to 1 kg / L.

[0011] Preferably, flue gas is bubbled into the lime milk solution by bubbling, and the solution is stirred. When the pH value of the suspension is approximately equal to 7, aeration is stopped.

[0012] The suspension is settled, the upper solution is decanted, and the lower solid is dried to obtain solid calcium carbonate. The solid calcium carbonate obtained by the method has a nanometer particle size and a relatively uniform size distribution, so that the catalyst prepared after loading the metal has better electrocatalytic carbon dioxide reduction performance.

[0013] The above calcium carbonate solid and metal chloride solution are mixed.

[0014] The metal chloride preferably includes one or more of copper chloride, zinc chloride and lead chloride.

[0015] The solid mass ratio of the metal chloride to the calcium carbonate is preferably 0.0001-10:1, more preferably 0.001-4:1, and further preferably (0.1-2):1.

[0016] The present invention has no particular limitation on the mixing method, and it can be a mixing method well known to those skilled in the art. The present invention preferably adopts a mechanical stirring method, and the rotation speed of the mechanical stirring is preferably 50-150 r / min, more preferably 100 r / min.

[0017] After stopping stirring, the system is allowed to stand, and after the suspension is settled and separated into layers, the upper layer of solution is decanted, and the lower layer of solid is dried to obtain a multi-metal supported calcium carbonate catalyst.

[0018] The catalyst is applied to a carbon dioxide electrolysis reactor, and a negative potential is applied. The corresponding metal (copper, zinc, lead) compounds are reduced to a metallic state and loaded on calcium carbonate. The in-situ generated catalyst can be used for large-scale carbon dioxide electrolysis to efficiently produce synthesis gas (loaded with zinc), pure formic acid (loaded with lead) and multi-carbon products (loaded with copper).

[0019] By adopting the above method, the ratio of calcium carbonate and corresponding metal (copper, zinc, lead) compounds can be freely adjusted by changing the type and concentration of metal salts to obtain calcium carbonate catalysts with different metal loadings and loadings.

[0020] The present invention also provides a multi-metal supported calcium carbonate catalyst prepared by the above preparation method, wherein the carrier of the catalyst is calcium carbonate, and the active substance is one or more of copper, zinc and lead.

[0021] Preferably, the loading amount of the active substance is 0.01% to 300%, more preferably 0.2% to 100%.

[0022] The multi-metal supported calcium carbonate catalyst provided by the present invention can be applied to carbon dioxide electrolysis.

[0023] A negative potential is applied to the catalyst, and the corresponding metal (copper, zinc, lead) compound is reduced to a metallic state, and then catalyzes the reaction of carbon dioxide.

[0024] Based on this, the present invention provides a method for catalyzing the electrolysis of carbon dioxide, comprising the following steps:

[0025] Mixing a multi-metal supported calcium carbonate catalyst and a binder solution in a dispersion to obtain a catalyst ink;

[0026] Applying the catalyst ink on the surface of a gas diffusion electrode and drying it to obtain a working electrode;

[0027] Assembling the working electrode into an electrocatalytic carbon dioxide reduction membrane cell to obtain an assembled cell stack;

[0028] The electrocatalytic carbon dioxide is electrolyzed by a constant potential method or a constant current method;

[0029] The multi-metal supported calcium carbonate catalyst is the multi-metal supported calcium carbonate catalyst prepared by the above preparation method or the above multi-metal supported calcium carbonate catalyst.

[0030] The dispersion liquid can be a general low boiling point solvent, preferably one or more of methanol, ethanol, propanol, and isopropanol.

[0031] In the catalyst ink, the concentration of the multi-metal supported calcium carbonate catalyst is preferably 1-10 mg / mL.

[0032] The volume ratio of the binder solution to the dispersion is preferably 0.001 to 1:1.

[0033] The concentration of the binder solution is preferably 0.1 wt% to 10 wt%.

[0034] The present invention has no particular limitation on the type of the adhesive, and the adhesive may be any suitable adhesive known to those skilled in the art.

[0035] Preferably, the multi-metal supported calcium carbonate catalyst and the binder solution are mixed in a dispersion liquid, and the catalyst is evenly dispersed by ultrasound to obtain a catalyst ink.

[0036] The present invention has no special limitation on the gas diffusion electrode, which can be any suitable gas diffusion electrode known to those skilled in the art, preferably a carbon-based material gas diffusion electrode or a PTFE gas diffusion electrode.

[0037] The catalyst loading on the gas diffusion electrode is preferably 0.05-5 mg / cm 2 .

[0038] Preferably, the electrolysis reaction adopts a three-electrode electrochemical system, which also includes a counter electrode and an electrolyte.

[0039] The counter electrode includes but is not limited to one or more of nickel foam, nickel mesh electrode, platinum mesh electrode, iridium tantalum electrode, iridium dioxide electrode and the like.

[0040] The electrolyte includes but is not limited to KOH solution, NaOH solution, KHCO 3 Solution, NaHCO 3 Solution, K 2 CO 3 Solution, Na 2 CO 3 solution, KCl solution, NaCl solution, K 2 SO 4 Solution and Na 2 SO 4 One or more solutions.

[0041] The carbon dioxide gas flow rate is preferably 0.01-200 SLM (liters per minute).

[0042] The flow rates of the cathode electrolyte and the anode electrolyte are preferably 0.01-100 mL / min.

[0043] The voltage used in the constant potential method is preferably 0-100 V.

[0044] The current used in the constant current method is preferably 0.001~1000 A.

[0045] Compared with the prior art, the present invention provides a method for batch-prepared multi-metal supported calcium carbonate catalyst based on flue gas absorption, comprising the following steps: S1) blowing flue gas into a lime milk solution and stirring, and when the suspension is neutral, stopping ventilation, settling the suspension, decanting the upper solution, and drying the lower solid to obtain a calcium carbonate solid; S2) mixing the above calcium carbonate solid and a solution of a metal chloride, standing, and after the suspension is settled and layered, decanting the upper solution, and drying the lower solid to obtain a multi-metal supported calcium carbonate catalyst.

[0046] This method uses flue gas, metal chloride and calcium oxide as raw materials. Through simple bubbling and stirring, a multi-metal supported calcium carbonate catalyst can be obtained. It is not affected by the flue gas composition and can be scaled up to kilograms, laying the foundation for subsequent catalyst scale-up experiments. The catalyst is used for large-scale carbon dioxide electrolysis and can efficiently obtain synthesis gas, pure formic acid and multi-carbon products. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The scanning electron microscope and transmission electron microscope images of calcium carbonate prepared by the bubbling method;

[0048] Figure 2 This is the XRD diffraction pattern of calcium carbonate prepared by bubbling method;

[0049] Figure 3 The scanning electron microscope and transmission electron microscope images of the copper-supported calcium carbonate catalyst;

[0050] Figure 4 The scanning electron microscope and transmission electron microscope images of zinc-supported calcium carbonate catalyst;

[0051] Figure 5 The scanning electron microscope and transmission electron microscope images of the lead-supported calcium carbonate catalyst;

[0052] Figure 6 CO for copper, lead, zinc supported calcium carbonate catalyst 2 Electrolytic performance diagram;

[0053] Figure 7 Copper-supported calcium carbonate catalyst for the CO stack 2 Electrolytic performance diagram;

[0054] Figure 8 CO for zinc-supported calcium carbonate catalyst stack 2 Electrolytic performance diagram;

[0055] Fig. 9 CO for lead-supported calcium carbonate catalyst stack 2 Electrolytic performance diagram;

[0056] Fig.10 CO over lead supported calcium carbonate catalyst 2 NMR characterization results of formic acid produced by electrolysis. DETAILED DESCRIPTION

[0057] In order to further illustrate the present invention, the following is a detailed description in conjunction with the embodiments. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention.

[0058] All common equipment, materials, reagents, etc. of the present invention are not particularly limited in their sources and can be purchased from the market or prepared according to conventional methods well known to those skilled in the art.

[0059] Example 1

[0060] Step (1): Weigh 1000 g of calcium oxide, add it into 50 L of tap water, and mechanically stir to obtain lime milk.

[0061] Step (2): Pour lime milk into the reaction kettle, blow in flue gas, stir, and stop aeration when the pH value of the suspension is approximately equal to 7.

[0062] Step (3): The suspension is allowed to settle, the upper layer of the solution is separated by decantation, and the lower layer of the solid is dried to obtain calcium carbonate solid.

[0063] Step (4): Calcium carbonate was mixed with 50 L of copper chloride solution (0.3 mol / L) in a reaction kettle and mechanically stirred for 3 hours at a speed of 100 r / min.

[0064] Step (5): Stop stirring, let stand, wait for the suspension to settle and separate into layers, decant the upper layer of solution, and dry the lower layer of solid to obtain a copper-supported calcium carbonate catalyst, labeled as Cu / CaCO 3 .

[0065] Figure 1 The scanning electron microscope image (a) and transmission electron microscope image (b) of calcium carbonate prepared by the bubbling method; it can be seen that the morphology of the obtained calcium carbonate is nano-scale flakes or particles.

[0066] Figure 2 This is the XRD diffraction pattern of calcium carbonate prepared by the bubbling method; it can be seen that the obtained calcium carbonate is a calcite crystal with high purity.

[0067] Figure 3 The scanning electron microscope image (a) and transmission electron microscope image (b) of the copper-loaded calcium carbonate catalyst; it can be seen that the morphology of calcium carbonate is still maintained, and the loaded copper presents a nanoflower morphology.

[0068] Example 2

[0069] The specific operation steps are the same as those in Example 1, except that the copper chloride solution added is replaced with a zinc chloride solution to prepare a zinc-supported calcium carbonate catalyst, which is labeled as Zn / CaCO 3 .

[0070] Figure 4 The scanning electron microscope image (a) and transmission electron microscope image (b) of the zinc-loaded calcium carbonate catalyst; it can be seen that the morphology of calcium carbonate is still maintained and the loaded zinc presents a granular morphology.

[0071] Example 3

[0072] The specific operation steps are the same as those in Example 1, except that the copper chloride solution added is replaced with lead chloride solution to prepare a lead-supported calcium carbonate catalyst, which is marked as Pb / CaCO 3 .

[0073] Figure 5 The scanning electron microscope image (a) and transmission electron microscope image (b) of the lead-loaded calcium carbonate catalyst; it can be seen that the morphology of calcium carbonate is still maintained and the loaded lead presents a granular morphology.

[0074] Example 4

[0075] The specific method of electrolyzing carbon dioxide using a metal-supported calcium carbonate catalyst is as follows:

[0076] Step 1: First, add 15 mg of metal-supported calcium carbonate catalyst to 3 mL of isopropanol solution, then add a certain amount of binder solution, and then ultrasonically mix for 30 min to obtain a uniform solution. The solution is coated on a 5 cm×5 cm gas diffusion electrode and baked and dried under an infrared lamp to obtain a working electrode.

[0077] Step 2: Stack the working electrode, anion exchange membrane and iridium dioxide anode to obtain a membrane electrode. Stack several membrane electrodes further to obtain a stack.

[0078] Step 3: Use 0.2 mol / L KHCO 3 The solution is the electrolyte of the anode tank, and a peristaltic pump is used to continuously flow the electrolyte at a flow rate of 40 mL / min. High-purity carbon dioxide is continuously introduced into the back of the gas diffusion electrode of the cathode tank at a flow rate of 1 SLM. The electrocatalytic carbon dioxide reduction reaction is carried out using the constant current method, and the constant current is set to 1~20 A.

[0079] Figure 6 CO for copper, lead, zinc supported calcium carbonate catalyst 2 Electrolysis performance diagram; it can be seen that before loading metal, calcium carbonate did not show carbon dioxide reduction performance. After loading copper, as the copper content changes, the carbon dioxide reduction products change from methane to polycarbon (including ethylene, ethanol, acetic acid, n-propanol, etc.); after loading lead and zinc, formic acid and synthesis gas are mainly obtained, respectively.

[0080] Figure 7 Copper-supported calcium carbonate catalyst for the CO stack 2 From the electrolysis performance diagram, it can be seen that the catalyst is able to electrolyze carbon dioxide under large current and achieve high selectivity to produce multi-carbon products.

[0081] Figure 8 CO for zinc-supported calcium carbonate catalyst stack2 Electrolysis performance diagram; the black line is the syngas production rate, and the blue line is the stack power. It can be seen that the catalyst is capable of high-power syngas production (rate of 19 liters per hour).

[0082] Fig. 9 CO for lead-supported calcium carbonate catalyst stack 2 Electrolysis performance diagram; the orange line is the selectivity of formic acid production during the electrolysis of carbon dioxide, and the blue line is the voltage monitoring result during the electrolysis process. It can be seen that the lead-supported calcium carbonate catalyst can achieve efficient and stable formic acid production.

[0083] Fig.10 CO over lead supported calcium carbonate catalyst 2 The NMR characterization results of formic acid produced by electrolysis show that the purity and concentration of the produced formic acid are very high, and no impurities are detected.

[0084] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for batch preparation of a multi-metal supported calcium carbonate catalyst based on flue gas absorption, comprising the following steps: S1) blowing flue gas into the lime milk solution and stirring, when the suspension is neutral, stopping the ventilation, settling the suspension, decanting the upper solution, and drying the lower solid to obtain calcium carbonate solid; S2) The calcium carbonate solid and the metal chloride solution are mixed and allowed to stand for precipitating and stratifying. The upper layer of the solution is decanted and the lower layer of the solid is dried to obtain a multi-metal supported calcium carbonate catalyst.

2. The method according to claim 1, characterized in that Components of the flue gas include carbon dioxide.

3. The method according to claim 1, characterized in that The metal chloride includes one or more of copper chloride, zinc chloride and lead chloride.

4. The method according to claim 1, characterized in that: The mass ratio of the metal chloride to the calcium carbonate solid is 0.0001-10:

1.

5. The method according to claim 1, characterized in that The concentration of the lime milk solution is 0.001-10 kg / L.

6. The multi-metal supported calcium carbonate catalyst prepared by the preparation method according to any one of claims 1 to 5, characterized in that: The carrier of the catalyst is calcium carbonate, and the active substance is one or more of copper, zinc and lead.

7. The multi-metal supported calcium carbonate catalyst according to claim 6, characterized in that: The loading amount of the active substance is 0.01% to 300%.

8. A method for catalyzing the electrolysis of carbon dioxide, comprising the following steps: Mixing a multi-metal supported calcium carbonate catalyst and a binder solution in a dispersion to obtain a catalyst ink; Applying the catalyst ink on the surface of a gas diffusion electrode and drying it to obtain a working electrode; Assembling the working electrode into an electrocatalytic carbon dioxide reduction membrane cell to obtain an assembled cell stack; The electrocatalytic carbon dioxide is electrolyzed by a constant potential method or a constant current method; The multi-metal supported calcium carbonate catalyst is a multi-metal supported calcium carbonate catalyst prepared by the preparation method according to any one of claims 1 to 5 or a multi-metal supported calcium carbonate catalyst according to any one of claims 6 to 7.

9. The method for catalyzing the electrolysis of carbon dioxide according to claim 8, characterized in that: The dispersion liquid is selected from one or more of methanol, ethanol, propanol and isopropanol; In the catalyst ink, the concentration of the multi-metal supported calcium carbonate catalyst is 1-10 mg / mL; The volume ratio of the binder solution to the dispersion is 0.001 to 1:1; The concentration of the binder solution is 0.1 wt%~10 wt%; The catalyst loading on the gas diffusion electrode is 0.05-5 mg / cm 2 .

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