Electrochemical reactor and application thereof, method for producing ethylene / carbon monoxide by electrochemical reforming of methane / carbon dioxide, and catalyst

Abstract

The present invention relates to the technical field of solid oxide electrolytic cells, and discloses an electrochemical reactor and an application thereof, a method for producing ethylene / carbon monoxide by the electrochemical reforming of methane / carbon dioxide, and a catalyst. The electrochemical reactor comprises an anode, a cathode, and an electrolyte layer disposed between the anode and the cathode, the anode comprising an anode carrier and an anode catalyst attached to the anode carrier, the cathode comprising a cathode carrier and a cathode catalyst attached to the cathode carrier, and the main component of both the anode carrier and the cathode carrier being yttria-stabilized zirconia, and the anode carrier and the cathode carrier each being provided with a microchannel structure. In the method for producing ethylene / carbon monoxide by the electrochemical reforming of methane / carbon dioxide, the electrochemical reactor exhibits the effects of improving Faraday efficiency, methane conversion rates, and C2 and ethylene selectivity, while reducing excessive oxidation products CO and CO2 generated at the anode.

Description

Electrochemical reactor and its application, method and catalyst for electrochemical reforming of methane / carbon dioxide to produce ethylene / carbon monoxide

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese patent application No. 202410346500.4 filed on March 25, 2024, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the technical field of solid oxide electrolytic cells, and in particular to an electrochemical reactor and its application, and a method and catalyst for electrochemical reforming of methane / carbon dioxide to produce ethylene / carbon monoxide. Background Art

[0004] The solid oxide electrolysis cell (SOEC) is a novel energy conversion device that simultaneously provides a high-temperature environment and an external electric field for the reaction system, catalyzing a series of chemical reactions that are difficult to achieve under conventional conditions. Under electrolysis, the SOEC can produce carbon monoxide by high-temperature electrolysis of carbon dioxide, while simultaneously generating oxygen at the other electrode. This technology has demonstrated promising results at both laboratory and pilot scales. However, the potential for SOEC applications in other chemical synthesis scenarios remains to be explored. Theoretically, when a SOEC electrolyzes carbon dioxide, a large number of highly reactive nascent oxygen atoms are generated at the anode. These nascent oxygen atoms combine to produce oxygen. If these nascent oxygen atoms can be effectively utilized in the reaction through rational design, high-value-added chemical products can be simultaneously produced at the anode, such as the direct electrocatalytic oxidation of methane to ethylene (and water). This reaction route holds promise not only for the conversion of methane to ethylene, but also for the simultaneous conversion of carbon dioxide molecules in biogas into carbon monoxide. In this way, the main components of biogas (methane and carbon dioxide) can be reformed into bulk chemical raw materials (ethylene and carbon monoxide) at the same time, with high atomic utilization rate and broad market prospects.

[0005] Many research institutions at home and abroad have studied the technology of methane electrothermal coupled oxidation to olefins based on SOEC reactor. For example, Ramaiyan et al. developed BaMg 0.33 Nb 0.67-x Fe x O 3-δ The material was used as an anode catalyst in SOEC to achieve methane oxidation coupling to ethylene at 800°C and 1V electrolysis potential. The product was a mixture of ethylene, CO2, and H2. The methane conversion rate was 12.5%, the ethylene selectivity was 50.3%, and the electrolysis Faraday efficiency was 20%. 1.575 Mo 0.5 O6-δ The material was used in the SOEC anode, achieving methane oxidation coupling to ethylene at 850°C and an electrolysis potential of 1.4V. The products were a mixture of ethylene, ethane, CO, CO2, and H2. The methane conversion rate was 11.61%, the C2 selectivity (ethane + ethylene) was 78.18%, and most of it was ethane. The C2 concentration of the outlet product was 16.7%. These results show that while SOEC has great application potential in chemical synthesis, the use of SOEC to convert methane to ethylene still has some systemic problems, including low Faradaic efficiency (low power utilization efficiency), poor ethylene selectivity in the product, and the easy production of over-oxidation products such as CO and CO2.

[0006] Therefore, it is necessary to develop a new catalyst and reactor to solve the above technical defects. Summary of the Invention

[0007] The purpose of the present invention is to overcome the problems of low Faraday efficiency caused by insufficient reaction activity of electrode catalysts and defects in electrode structure in the prior art, as well as the problem of easy generation of excessive oxidation products CO and CO2 due to multiple types of side reactions at the reactor anode, and to provide an electrochemical reactor and its application, and a method and catalyst for electrochemical reforming of methane / carbon dioxide to produce ethylene / carbon monoxide.

[0008] In order to achieve the above-mentioned object, the first aspect of the present invention provides an electrochemical reactor with the function of electrochemical reforming methane / carbon dioxide to produce ethylene / carbon monoxide, the electrochemical reactor comprising an anode and a cathode and an electrolyte layer disposed between the anode and the cathode, the anode comprising an anode carrier and an anode catalyst attached to the anode carrier, the cathode comprising a cathode carrier and a cathode catalyst attached to the cathode carrier, and the main components of the anode carrier and the cathode carrier are each independently yttria-stabilized zirconia, characterized in that the anode carrier and the cathode carrier each have a microchannel structure; the anode catalyst comprises a perovskite structure electrocatalyst and a metal oxide MO n thermal catalysts;

[0009] M is at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Mo, Ru, Sn, Ce, and Pr; 1≤n≤3.

[0010] The second aspect of the present invention provides use of the electrochemical reactor described in the first aspect of the present invention in the electrochemical reforming of methane / carbon dioxide to produce ethylene / carbon monoxide.

[0011] The third aspect of the present invention provides a method for producing ethylene and carbon monoxide by electrochemical reforming of methane and carbon dioxide. The method comprises, under electrolysis reaction conditions, introducing a carbon dioxide-containing gas into the cathode of the electrochemical reactor described in the first aspect of the present invention, introducing a methane-containing gas into the anode, and collecting the obtained ethylene gas and carbon monoxide gas.

[0012] The fourth aspect of the present invention provides a catalyst, characterized in that the catalyst comprises a perovskite structure electrocatalyst and a metal oxide MO n thermal catalysts;

[0013] M is at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Mo, Ru, Sn, Ce, and Pr; 1≤n≤3.

[0014] The fifth aspect of the present invention provides use of the catalyst described in the fourth aspect of the present invention in an electrochemical reactor.

[0015] The present invention uses perovskite structure electrocatalyst and metal oxide MO n When a thermal catalyst is used as the anode catalyst and yttria-stabilized zirconia (YSZ) with a microchannel structure is used as the anode support and cathode support, the resulting electrochemical reactor can significantly improve ethylene selectivity and Faradaic efficiency when used for the electrochemical reforming of methane / carbon dioxide to produce ethylene / carbon monoxide, achieving higher selectivity and higher efficiency in the oxidation of methane to ethylene. For example, using the electrochemical reactor of Example 1, when the operating temperature is 850°C, the electrolysis voltage is 2.5V, methane is introduced to the anode side, and carbon dioxide is introduced to the cathode side, the electrolysis current density can reach 100mA·cm -2 The ethylene selectivity in the anode gas product can reach more than 80%, and the anode Faraday efficiency can reach more than 50%; at the same time, the Faraday efficiency of reducing carbon dioxide to produce carbon monoxide at the cathode reaches nearly 90%. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 is a schematic diagram of a methane / carbon dioxide electrochemical reactor based on a solid oxide electrolysis cell;

[0017] FIG2 is an electron microscope photograph of a porous microchannel YSZ electrode support in an electrochemical reactor. (a) is the surface of the porous skeleton of the microchannel structure, and (b) is the side of the porous skeleton of the microchannel structure.

[0018] FIG3 is an electron microscope photograph of a porous microchannel YSZ anode support loaded with an electrocatalyst in an electrochemical reactor;

[0019] FIG4 is an XRD test result of a porous microchannel YSZ anode support loaded with an electrocatalyst in an electrochemical reactor;

[0020] FIG5 is a SEM photo and EDS image of the anode in the electrochemical reactor;

[0021] FIG6 is an electrochemical impedance spectroscopy test result of the electrolytic cell of the electrochemical reactor used in Example 1 at 850° C. in a methane / carbon dioxide atmosphere;

[0022] 7 is a current density-voltage curve of the electrolytic cell of the electrochemical reactor used in Example 1 at 850° C. in a methane / carbon dioxide atmosphere;

[0023] FIG8 is an electrochemical reactor used in Example 1 at 850°C and 100 mA / cm 2 Test results of anode tail gas composition after methane electrolysis at the electrolysis current density;

[0024] FIG9 is a test result of the cathode outlet tail gas composition after electrolysis of carbon dioxide at 850° C. and different current densities in the electrochemical reactor used in Example 1;

[0025] Figure 10 is the electrochemical reactor used in Example 1 at 850 ° C, 100 mA / cm 2 Results of electrolytic methane operation stability test under different current densities.

[0026] DESCRIPTION OF REFERENCE NUMERALS 1 YSZ pore wall 2 catalyst support layer DETAILED DESCRIPTION

[0027] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0028] A first aspect of the present invention provides an electrochemical reactor comprising an anode and a cathode and an electrolyte layer disposed between the anode and the cathode, wherein the anode comprises an anode carrier and an anode catalyst attached to the anode carrier, and the cathode comprises a cathode carrier and a cathode catalyst attached to the cathode carrier, wherein the main components of the anode carrier and the cathode carrier are each independently yttria-stabilized zirconia, and wherein the anode carrier and the cathode carrier each have a microchannel structure;

[0029] Wherein, the anode catalyst comprises a perovskite structure electrocatalyst and a metal oxide MO n thermal catalysts;

[0030] M is at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Mo, Ru, Sn, Ce, and Pr; 1≤n≤3.

[0031] The main component means that the main component accounts for more than 80% of the total weight of the anode and cathode carriers, generally more than 90%.

[0032] In the present invention, the anode catalyst can catalyze the oxidation of methane into ethylene.

[0033] In the present invention, the cathode catalyst can catalyze carbon dioxide to generate carbon monoxide.

[0034] In some embodiments of the present invention, preferably, the closed-pore ratio of the microchannel structures of the cathode and the anode is 0-5%, preferably 0-1%.

[0035] In the present invention, closed cells refer to cells that are not connected to the outside, and the closed cell ratio is also called the closed porosity, which refers to the ratio of the volume of closed cells to the apparent volume.

[0036] In the present invention, the closed cell ratio is measured by a nano-computed tomography (Nano CT) method.

[0037] In some embodiments of the present invention, as shown in FIG2 , the microchannel structures of the cathode and the anode are layered pores, and the aspect ratio of the pore cross section is 1-20:1, preferably 1-10:1.

[0038] In the present invention, the layered pores refer to parallel pores in the anode and cathode supports, with the cross-sectional morphology of the pores being approximately rectangular. When the aspect ratio of the pore cross-section is within the above-mentioned range, the electrochemical reactor can achieve improved C2 and ethylene selectivity and Faradaic efficiency. The length and width of the pore cross-section can be measured by scanning electron microscopy (SEM) or nano-computed tomography (Nano CT) on a cross-section of the anode / cathode supports.

[0039] In the present invention, the Faraday efficiency η is calculated by combining an electrochemical workstation with a gas chromatograph. For example, the electrochemical workstation is set to a constant current output mode, and the current density is specified as I (A / cm 2 ), the inlet gas flow rate is V (mL / s), the ethylene content in the outlet gas measured by gas chromatography is c%, and the Faraday efficiency of methane electrolysis to ethylene through the electrolysis reactor is:

[0040] Where F is the Faraday constant 96500C / mol, V m The standard volume of an ideal gas is 22400 mL / mol, and the number 4 is the number of electrons required to transfer to produce one molecule of ethylene.

[0041] In the present invention, the Faradaic efficiency can also be calculated by actual ethylene production / theoretical production.

[0042] In some embodiments of the present invention, preferably, the average pore size of the openings of the microchannel structure of the cathode and the anode away from the electrolyte layer at one end is 2-300 microns in the length direction, preferably 2-200 microns; the average pore size in the width direction is 2-30 microns, preferably 2-20 microns.

[0043] In some embodiments of the present invention, preferably, the thickness of the anode support and the anode support are each independently 100-2000 microns, preferably 100-800 microns.

[0044] In the present invention, the pore diameter and pore wall thickness are measured by scanning electron microscopy (SEM) or nano-computed tomography (Nano CT).

[0045] In the present invention, the layered pores of the anode carrier and the cathode carrier can provide a certain mechanical strength and achieve a self-supporting effect.

[0046] In some embodiments of the present invention, preferably, the thickness of the electrolyte layer is 400-500 microns.

[0047] In some embodiments of the present invention, preferably, the anode catalyst and cathode catalyst are uniformly distributed as a continuous phase on the inner walls of the pores (microchannel structure) of the anode support and cathode support, respectively, as can be seen in electron microscope images. The morphology of the support pore structure and the catalyst loading is shown in Figures 2 and 3, where it can be seen that the inner walls of the pores are uniformly distributed as a continuous phase. Preferably, the thickness of the anode catalyst and cathode catalyst is 100-500 nm.

[0048] The thickness of the anode carrier and the cathode carrier is measured by a vernier caliper or a micrometer.

[0049] The thickness of the electrolyte layer is measured by a micrometer.

[0050] The thickness of the anode catalyst and the cathode catalyst is measured by scanning electron microscopy.

[0051] In some embodiments of the present invention, preferably, based on the total mass of the anode, the perovskite structure electrocatalyst and the metal oxide MO n The content of is 10-60 wt %. This content range can take into account both the mechanical strength and catalytic activity of the anode, achieving the effect of catalyzing the electrochemical conversion reaction while maintaining the basic stability of the electrode structure morphology.

[0052] In the present invention, the perovskite structure electrocatalyst and the metal oxide MO n The chemical structure of the two can be characterized by XRD spectrum; the contents of the two can be determined by X-ray photoelectron spectroscopy.

[0053] In some embodiments of the present invention, preferably, the perovskite-structured electrocatalyst and the metal oxide MO n have a mass ratio of 0.5 - 2:1; preferably 1 - 1.5:1. This mass ratio range can enable the composite anode to achieve the effects of both conductivity and catalytic activity for alkane conversion.

[0054] In the present invention, the anode catalyst includes a perovskite-structured electrocatalyst and a metal oxide MO n thermal catalyst. Among them, the perovskite structure and crystal phase of the electrocatalyst can be tested by XRD, as shown in Figure 4 (taking La 1-x Sr x CoO 3-δ electrocatalyst and NiO thermal catalyst as an example). The electrocatalyst and the thermal catalyst cooperate together to promote the anode reaction.

[0055] Although the object of the present invention can be achieved as long as it contains both a perovskite-structured electrocatalyst and a metal oxide MO n thermal catalyst, preferably, the perovskite-structured electrocatalyst is located between the metal oxide MO n thermal catalyst and the anode support.

[0056] In some embodiments of the present invention, preferably, the perovskite structure includes rare earth elements, alkaline earth metal elements, Group VIII elements, and oxygen elements; preferably includes La, Sr, Co, and O elements; more preferably, the perovskite structure is La 1-x Sr x CoO 3-δ ; where 0 < x ≤ 0.5 and 0 ≤ δ ≤ 0.5. This x range and δ range can enable the electrochemical reactor to achieve the effects of improving the selectivity of C2 and ethylene and the Faraday efficiency.

[0057] In the present invention, δ is the value required to satisfy the valence of the elements other than oxygen atoms in the perovskite structure.

[0058] In some embodiments of the present invention, preferably, the value of x can be 0.1, 0.2, 0.3, 0.4, or 0.5.

[0059] In some embodiments of the present invention, preferably, the cathode catalyst is at least one of NiO, CuO, and CeO2, and based on the total mass of the cathode, the content of the cathode catalyst is 30 - 60 wt%. This content range can balance the mechanical strength and catalytic activity of the cathode, achieving the effect of maintaining the basic stability of the electrode structure morphology while catalyzing the electrochemical conversion reaction.

[0060] In some embodiments of the present invention, preferably, the component of the electrolyte layer is YSZ.

[0061] In some embodiments of the present invention, the electrolyte layer preferably has a dense structure with a porosity of less than 5%. This allows the electrolyte layer to effectively isolate the atmosphere on both sides of the reactor and prevent side reactions. The porosity is the ratio of through pores to total pores, as measured by nano-computed tomography (Nano CT).

[0062] In some embodiments of the present invention, preferably, the method for preparing the electrochemical reactor comprises:

[0063] Step 1: preparing a porous skeleton with a microchannel structure;

[0064] Step 2: Adhere the two microchannel structure porous skeletons in step 1 to the front and back sides of the electrolyte layer, and calcine to form an electrolytic cell skeleton;

[0065] Step 3: impregnate the anode catalyst precursor and the cathode catalyst precursor into the front and back sides of the electrolyte layer in step 2 respectively, and then calcine to obtain an electrochemical reactor.

[0066] Experiments have shown that during the process of preparing an electrochemical reactor using the above-mentioned preparation method of the present invention, especially the microchannel structure skeleton prepared by the method in the preparation example, the closed-pore ratio of the electrochemical reactor and the microchannel structure skeleton remain unchanged.

[0067] In the present invention, the porous skeleton with microchannel structure can be used as both an anode support and a cathode support in the embodiments and comparative examples. Therefore, the thickness of the porous skeleton with microchannel structure is consistent with that of the anode support and / or cathode support.

[0068] In some embodiments of the present invention, preferably, in step 1, the auxiliary agent is selected from at least one of a dispersant, a thickener, a binder and an emulsifier.

[0069] In some embodiments of the present invention, preferably, the dispersant is selected from at least one of ethylene bisstearamide, triethanolamine and sodium polyacrylate, more preferably ethylene bisstearamide.

[0070] In some embodiments of the present invention, preferably, the thickener is selected from at least one of sodium polyacrylate, polyvinyl alcohol and polyvinyl butyral, more preferably sodium polyacrylate.

[0071] In some embodiments of the present invention, preferably, the binder is at least one selected from dioctyl adipate, dibutyl adipate and polyethylene glycol, more preferably dioctyl adipate.

[0072] In some embodiments of the present invention, preferably, the emulsifier is selected from at least one of carboxymethyl cellulose, ethyl cellulose and polyvinyl pyrrolidone, more preferably carboxymethyl cellulose.

[0073] In some embodiments of the present invention, preferably, in step 1, the preparation method comprises mixing YSZ, water and an additive, and sequentially performing vacuum freeze-drying and high-temperature calcination.

[0074] In the present invention, vacuum freeze drying and high-temperature calcination are carried out in sequence, so that the skeleton prepared in step 1 can have a microchannel structure.

[0075] In some embodiments of the present invention, preferably, in step 1, YSZ and water are first mixed and the pH value is adjusted to 5-11; the pH adjusting agent is selected from at least one of 30 wt% ammonia water, sodium hydroxide and magnesium hydroxide.

[0076] In some embodiments of the present invention, preferably, in step 1, the additive is mixed with YSZ and water by ultrasonic mixing and ball milling.

[0077] In some embodiments of the present invention, preferably, in step 1, the vacuum freeze-drying process further comprises pre-freezing the mixed system of YSZ, water and auxiliary agents.

[0078] In some embodiments of the present invention, preferably, in step 1, the high-temperature calcination is followed by a grinding and thinning treatment.

[0079] In some embodiments of the present invention, preferably, in step 1, the mass ratio of YSZ to water is 0.5-5:1, more preferably, the mass ratio of YSZ to water is selected from 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5.

[0080] YSZ powder can be any commercially available yttria-stabilized zirconia product. For example, the weight ratio of yttria to zirconia can be 3-10:100, specifically 8Y, 8YS, or 8YSB grades manufactured by Tosoh of Japan. This weight ratio range allows the synthesized anode and cathode supports to achieve moderate strength and excellent pore morphology.

[0081] In some embodiments of the present invention, the dispersant, thickener, binder, and emulsifier are preferably added in an amount of 0.1-5% by weight of the total mass of the YSZ, water, and additive mixture in step 1, more preferably 0.5%, 1%, 2%, 3%, 4%, or 5%. This amount range ensures that the resulting anode and cathode supports have moderate strength and excellent pore morphology.

[0082] In some embodiments of the present invention, preferably, the vacuum freeze-drying conditions include: a temperature of -90°C to -10°C, more preferably -80°C, -70°C, -60°C, -50°C, -40°C, -30°C or -20°C; and a time of 6-24 hours.

[0083] In some embodiments of the present invention, preferably, the pre-freezing temperature is -10°C to -80°C, more preferably -20°C, -30°C, -40°C, -50°C, -60°C, -70°C or -80°C, and the time is 0.5-4 hours. The vacuum freeze-drying conditions include a vacuum degree of 0.1-10 Pa, a temperature of -90 to -10°C, and a time of 6-24 hours.

[0084] In some embodiments of the present invention, preferably, the high-temperature calcination temperature is 1000-1400°C, for example, 1000°C, 1050°C, 1100°C, 1200°C, 1300°C or 1400°C, and the calcination time is 1-6 hours.

[0085] In some embodiments of the present invention, the final thickness after grinding and thinning is preferably 100-800 microns, for example, 100 microns, 200 microns, 300 microns, 400 microns, 500 microns, 600 microns, 700 microns, or 800 microns. This thickness range allows the anode and cathode carriers to have both a certain mechanical strength and good conductive properties.

[0086] The grinding and thinning method may be, for example, grinding with a grinder or a diamond wire cutting machine.

[0087] In some embodiments of the present invention, preferably, in step 2, a binder is used to complete the process of adhering to the front and back surfaces of the electrolyte layer.

[0088] In some embodiments of the present invention, preferably, the binder is a composite binder, more preferably at least one of a composition of YSZ-terpineol-ethyl cellulose, YSZ-polyvinyl butyral-ethanol and YSZ-polyethylene glycol-ethanol, more preferably a composition of YSZ-terpineol-ethyl cellulose. The role of the binder is to adhere the microchannel structure porous skeleton to the electrolyte layer. Any binder that can play this role can be used in the present invention, and any commercially available product of such a binder can play this role. For example, the commercial product of Sigma-Aldrich's ethylene bis stearamide, the commercial product sodium polyacrylate of INNOCHEM, the commercial product magnesium aluminum silicate of Aladdin, the commercial product carboxymethyl cellulose of INNOCHEM, etc.

[0089] In some embodiments of the present invention, preferably, the mass ratio of each substance in the YSZ-terpineol-ethyl cellulose binder is: YSZ:terpineol = 0.2-5:1, preferably 0.2-2:1, for example, 0.2:1, 0.4:1, 0.6:1, 0.8:1, 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1 or 2:1; ethyl cellulose:terpineol = 0.01-0.1:1, for example, 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1 or 0.1:1.

[0090] In some embodiments of the present invention, preferably, in step 2, the calcination temperature is 1200-1500° C., and the calcination time is 1-6 hours.

[0091] In some embodiments of the present invention, preferably, in step three, the anode catalyst precursor is an aqueous solution S1 of a salt of metal M and an aqueous solution S3 containing a lanthanum salt, a strontium salt and a cobalt salt.

[0092] In some embodiments of the present invention, preferably, in step three, the cathode catalyst precursor is an aqueous solution S2 of a nickel salt.

[0093] In some embodiments of the present invention, preferably, the salt of metal M is nitrate of M.

[0094] In some embodiments of the present invention, preferably, the lanthanum salt, strontium salt and cobalt salt are nitrates.

[0095] In some embodiments of the present invention, preferably, in step three, the metal M in the solution S1 is one or more of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Mo, Ru, Sn, Ce, and Pr.

[0096] More preferably, the metal M in the mixed solution S1 is Ni.

[0097] In some embodiments of the present invention, preferably, in step 3, when preparing the solution S3, the molar ratio of the lanthanum salt, strontium salt and cobalt salt is according to La 1-x Sr x CoO 3-δ Calculate chemical formulas.

[0098] In some embodiments of the present invention, preferably, in step three, an acidic substance is added when preparing the solution S3, wherein the acidic substance is selected from at least one of citric acid, glycine and ethylenediaminetetraacetic acid, preferably citric acid.

[0099] In some embodiments of the present invention, preferably, in step three, the molar ratio of the acid substance to the total amount of the lanthanum salt, strontium salt and cobalt salt is 1:0.5-2.

[0100] In some embodiments of the present invention, preferably, in step three, the calcination includes one calcination or multiple calcinations; more preferably, each time the solution S1, S2 or S3 is infiltrated into the microchannel of the electrolytic cell skeleton, the electrolytic cell skeleton is calcined once.

[0101] In some embodiments of the present invention, preferably, in step three, the calcination temperature is 500-1000°C, more preferably 500°C, 600°C, 700°C, 800°C, 900°C or 1000°C.

[0102] In some embodiments of the present invention, preferably, the catalyst loading of the cathode / anode is 10-60% of the total mass of the cathode / anode, for example, 10%, 20%, 30%, 40%, 50% or 60%.

[0103] The second aspect of the present invention provides use of the electrochemical reactor described in the first aspect of the present invention in the electrochemical reforming of methane / carbon dioxide to produce ethylene / carbon monoxide.

[0104] The electrochemical reactor provided by the present invention has a microchannel structure on the cathode carrier and the anode carrier, and is particularly suitable for reactions such as the electrochemical reforming of methane / carbon dioxide to produce ethylene / carbon monoxide, in combination with a perovskite structure and a metal oxide as an anode catalyst.

[0105] The third aspect of the present invention provides a method for producing ethylene and carbon monoxide by electrochemical reforming of methane and carbon dioxide. The method comprises, under electrolysis reaction conditions, introducing a carbon dioxide-containing gas into the cathode of the electrochemical reactor described in the first aspect of the present invention, introducing a methane-containing gas into the anode, and collecting the obtained ethylene gas and carbon monoxide gas.

[0106] In some embodiments of the present invention, preferably, the electrolysis reaction conditions include a temperature of 600-900°C, a gas flow rate of 10-200 mL / min / cm 2 , current density is 10-1000mA / cm 2 .

[0107] The fourth aspect of the present invention provides a catalyst, characterized in that the catalyst comprises a perovskite structure electrocatalyst and a metal oxide MO n thermal catalysts;

[0108] M is at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Mo, Ru, Sn, Ce, and Pr; 1≤n≤3.

[0109] In some embodiments of the present invention, preferably, the perovskite structure comprises rare earth elements, alkaline earth metal elements, Group VIII elements and oxygen elements; preferably, it comprises La, Sr, Co and O elements; more preferably, the perovskite structure is La 1-x Sr x CoO 3-δ ; where 0 < x ≤ 0.5 and 0 ≤ δ ≤ 0.5. These ranges of x and δ can enable the electrochemical reactor to achieve the effects of improving the selectivity of C2 and ethylene and the Faraday efficiency.

[0110] In the present invention, δ is the value required to satisfy the valence of the elements other than oxygen atoms in the perovskite structure.

[0111] In some embodiments of the present invention, preferably, the value of x can be 0.1, 0.2, 0.3, 0.4 or 0.5.

[0112] In some embodiments of the present invention, preferably, the mass ratio of the perovskite structure electrocatalyst to the metal oxide MO n is 0.5 - 2:1; preferably 1 - 1.5:1.

[0113] The fifth aspect of the present invention provides the application of the catalyst described in the fourth aspect of the present invention in an electrochemical reactor.

[0114] In some embodiments of the present invention, preferably, the application includes the application in the anode and / or cathode in an electrochemical reactor, and more preferably the application as an anode catalyst and / or a cathode catalyst.

[0115] The present invention will be further described below in conjunction with specific embodiments.

[0116] YSZ is a commercially available product of the 8Y grade produced by Tosoh Corporation of Japan, and the weight ratio of zirconia to yttria is 92:8; ethylene bisstearamide is a commercially available product of Sigma-Aldrich Corporation; sodium polyacrylate is a commercially available product of INNOCHEM Corporation; magnesium aluminum silicate is a commercially available product of Aladdin Corporation; carboxymethyl cellulose is a commercially available product of INNOCHEM Corporation.

[0117] In the present invention, ethylene selectivity (%) = 2 × ethylene production / methane consumption × 100%.

[0118] In the present invention, the outlet CO production = thermochemical CO production + electrochemical CO production. The methane consumption is calculated based on the methane amounts at the inlet and outlet, and the hydrogen consumption is calculated based on the hydrogen amounts at the inlet and outlet.

[0119] Preparation Example 1

[0120] 5.3 g of YSZ was weighed and mixed with 10 mL of water, and the pH of the solution was adjusted to 10 with aqueous ammonia. Under magnetic stirring, 0.4 g of ethylene bisstearamide, 0.3 g of sodium polyacrylate, 0.5 g of dioctyl adipate, 0.4 g of magnesium aluminum silicate, and 0.1 g of carboxymethyl cellulose were added to the mixed solution. The mixture was thoroughly stirred and placed in an ultrasonic cleaner at 1000 W for 60 minutes. The slurry was then transferred to a ball mill and milled for 2 hours to obtain a mixed slurry. The mixed slurry was poured into a low-temperature constant temperature reactor and pre-frozen at -70°C for 2 hours to form the slurry. The slurry was then transferred to a vacuum freeze dryer in the frozen state and freeze-dried at -60°C and 1.0 Pa for 12 hours to obtain a YSZ skeleton embryo with a microchannel structure. The microchannel structure YSZ skeleton embryo was calcined at 1250° C. for 2 hours, and then polished and thinned to obtain a microchannel structure skeleton D1 with a thickness of about 600 μm.

[0121] Wherein, the closed-pore ratio of the microchannel structure pores is 0.8%.

[0122] The average aspect ratio of the channel cross section is 7.5:1.

[0123] The average pore diameter of the pores at one end of the microchannel structure away from the electrolyte layer in the length direction is 60 micrometers, and the average pore diameter in the width direction is 8 micrometers.

[0124] Scanning electron microscopy was used to characterize the morphology of the porous microchannel structure framework, and the results are shown in Figure 2. (a) shows the surface of the porous microchannel structure framework, and (b) shows the side of the porous microchannel structure framework. The figure shows that the microchannels in the anode framework have a pore size of 5-10 microns, are straight, and are relatively evenly distributed.

[0125] Preparation Example 2

[0126] 5.8g of YSZ was weighed and mixed with 10mL of water, and the pH of the solution was then adjusted to 9 with aqueous ammonia. Under magnetic stirring, 0.5g of ethylene bisstearamide, 0.1g of sodium polyacrylate, 0.25g of dioctyl adipate, 0.3g of magnesium aluminum silicate, and 0.25g of carboxymethyl cellulose were added to the mixed solution and stirred thoroughly. The solution was placed in an ultrasonic cleaner set to 1000W for 30 minutes, and then the slurry was transferred to a ball mill and ball-milled for 2 hours to obtain a mixed slurry. The mixed slurry was poured into a low-temperature constant temperature reactor and pre-frozen at -50°C for 2 hours to form it. Then, in the frozen state, it was transferred to a vacuum freeze dryer and vacuum-dried at -65°C and 1.3 Pa for 12 hours to obtain a YSZ skeleton embryo with a microchannel structure. The microchannel structure YSZ skeleton embryo was calcined at a high temperature of 1180° C. for 2 hours, and then polished and thinned to obtain a microchannel structure skeleton D2 with a thickness of about 600 μm.

[0127] Wherein, the closed-pore ratio of the microchannel structure pores is 0%.

[0128] The average aspect ratio of the channel cross section is 10:1.

[0129] The average pore size of the pores at one end of the microchannel structure away from the electrolyte layer in the length direction is 50 microns, and the average pore size in the width direction is 5 microns.

[0130] Preparation Example 3

[0131] 6g of YSZ was weighed and mixed with 10mL of water, and the pH of the solution was adjusted to 10 with aqueous ammonia. Under magnetic stirring, 0.2g of ethylene bisstearamide, 0.35g of sodium polyacrylate, 0.15g of dioctyl adipate, 0.1g of magnesium aluminum silicate, and 0.43g of carboxymethyl cellulose were added to the mixed solution. The mixture was thoroughly stirred and placed in an ultrasonic cleaner at 1000W for 45 minutes. The slurry was then transferred to a ball mill and milled for 1.5 hours to obtain a mixed slurry. The mixed slurry was poured into a low-temperature constant temperature reactor and pre-frozen at -60°C for 2 hours to form a mold. After being frozen, it was transferred to a vacuum freeze dryer and freeze-dried at -50°C and 1.1 Pa for 10 hours to obtain a YSZ skeleton embryo with a microchannel structure. The microchannel structure YSZ skeleton embryo was calcined at a high temperature of 1230° C. for 3 hours, and then polished and thinned to obtain a microchannel structure skeleton D3 with a thickness of about 600 μm.

[0132] Wherein, the closed-pore ratio of the microchannel structure pores is 0.9%.

[0133] The average aspect ratio of the channel cross section is 5:1.

[0134] The average pore diameter of the pores at one end of the microchannel structure away from the electrolyte layer in the length direction is 40 micrometers, and the average pore diameter in the width direction is 8 micrometers.

[0135] Preparation Example 4

[0136] 5.3 g of YSZ (zirconia:yttrium oxide weight ratio of 92:8) was weighed and mixed with 10 mL of water, and the pH of the solution was adjusted to 10 with aqueous ammonia. Under magnetic stirring, 0.4 g of ethylene bisstearamide, 0.3 g of sodium polyacrylate, 0.5 g of dioctyl adipate, 0.4 g of magnesium aluminum silicate, and 0.1 g of carboxymethyl cellulose were added to the mixed solution. The mixture was thoroughly stirred and placed in an ultrasonic cleaner at 1000 W for 60 minutes. The slurry was then transferred to a ball mill and milled for 2 hours to obtain a mixed slurry. The mixed slurry was poured into a cryostat reactor and pre-frozen at -20°C. It was then transferred to a vacuum freeze dryer and freeze-dried at -50°C and 1.4 Pa for 12 hours to obtain a YSZ skeleton embryo with a microchannel structure. The microchannel structure YSZ skeleton embryo was calcined at a high temperature of 1250° C. for 2 hours, and then polished and thinned to obtain a microchannel structure skeleton D4 with a thickness of about 600 μm.

[0137] Wherein, the closed-pore ratio of the microchannel structure pores is 1%.

[0138] The average aspect ratio of the channel cross section is 7.5:1.

[0139] The average pore diameter of the pores at one end of the microchannel structure away from the electrolyte layer in the length direction is 60 micrometers, and the average pore diameter in the width direction is 8 micrometers.

[0140] Example 1

[0141] Preparation of the electrolytic cell framework: Weigh 0.6 g of YSZ powder and press it into a disc-shaped compact with a diameter of ~2 cm to form an electrolyte disc. Two microchannel-structured porous frameworks D1 obtained in Preparation Example 1 were bonded to the front and back of the disc using a YSZ-terpineol-ethyl cellulose binder. The resulting electrolyte disc was then calcined at 1380°C for 3 h to obtain the electrolytic cell framework A1.

[0142] Preparation of electrochemical reactor: According to the molecular formula La 0.6 Sr 0.4 CoO 3-δ0.03 mol of lanthanum nitrate, 0.02 mol of strontium nitrate, and 0.05 mol of cobalt nitrate were weighed in stoichiometric ratios and dissolved in 60 mL of deionized water. 0.1 mol of citric acid was added to obtain a mixed solution S3. 0.05 mol of Ni(NO3)2 was added to 50 mL of deionized water to fully dissolve it, and 0.05 mol of citric acid was added to obtain a mixed solution B3. 20 μL of mixed solution S3 was added to the microchannel on one side of the electrolytic cell skeleton A1 using a pipette and calcined at 800°C for 2 hours. Then, ~40 μL of mixed solution B3 was added to the microchannels on both sides of the electrolytic cell skeleton A1 using a pipette (~20 μL added to each side) in two portions and calcined at 800°C for 2 hours. The above impregnation-sintering steps were repeated until the cathode catalyst loading reached ~30 wt% of the total cathode mass and the anode catalyst loading reached ~35 wt% of the total anode mass, thereby obtaining an electrochemical reactor C1. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterize the morphology and surface energy spectrum of the anode, and the results are shown in Figure 3. 0.6 Sr 0.4 CoO 3-δ The electrocatalyst and NiO thermal catalyst are evenly distributed on the inner wall of the pores formed by YSZ, and a continuous phase has been formed. 0.6 Sr 0.4 CoO 3-δ The electrocatalyst has a perovskite structure.

[0143] The electrochemical reactor of this embodiment includes:

[0144] Electrolyte layer: YSZ, which has a dense structure and a porosity of <5%;

[0145] The thicknesses of the anode catalyst and cathode catalyst are 100 nm and 150 nm respectively;

[0146] The thickness of the electrolyte layer is 450 microns;

[0147] The mass ratio of the perovskite structure electrocatalyst to the metal oxide thermal catalyst is 1.1:1.

[0148] Example 2

[0149] Preparation of the electrolytic cell framework: Weigh 0.6 g of YSZ powder and press it into a disc-shaped compact with a diameter of ~2 cm to form an electrolyte disc. Two microchannel-structured porous frameworks D2 obtained in Preparation Example 2 were bonded to the front and back of the disc using a YSZ-terpineol-ethyl cellulose binder. The resulting electrolytic cell framework A2 was then calcined at 1180°C for 2 h.

[0150] Preparation of electrochemical reactor: According to the molecular formula La 0.9 Sr 0.1 CoO 3-δ 0.09 mol of lanthanum nitrate, 0.01 mol of strontium nitrate, and 0.1 mol of cobalt nitrate were weighed in stoichiometric proportions and dissolved in 120 mL of deionized water. 0.3 mol of citric acid was added to obtain a mixed solution S3. 0.055 mol of Ni(NO3)2 was added to 50 mL of deionized water to fully dissolve it, and 0.055 mol of citric acid was added to obtain a mixed solution B3. 20 μL of mixed solution S3 was added to the microchannels on one side of the electrolytic cell skeleton A2 using a pipette and calcined at 600°C for 2 hours. Then, ~40 μL of mixed solution B3 was added to the microchannels on both sides of the electrolytic cell skeleton A2 using a pipette (~20 μL added to each side) and calcined at 600°C for 2 hours. The above impregnation-sintering steps were repeated until the cathode catalyst loading reached ~50 wt% of the total cathode mass and the anode catalyst loading reached ~55 wt% of the total anode mass, obtaining an electrochemical reactor C2. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterize the morphology and surface energy spectrum of the anode, and the results were similar to those in Figure 3. 0.9 Sr 0.1 CoO 3-δ The electrocatalyst and NiO thermal catalyst are evenly distributed on the inner wall of the pores formed by the YSZ, forming a continuous phase. The electrochemical reactor of this embodiment includes:

[0151] Electrolyte layer: The main component is YSZ, and the electrolyte layer has a dense structure with a porosity of <5%;

[0152] The thicknesses of the anode catalyst and cathode catalyst are 150 nm and 150 nm respectively;

[0153] The thickness of the electrolyte layer is 400 microns;

[0154] The mass ratio of the perovskite structure electrocatalyst to the metal oxide thermal catalyst is 1.2:1.

[0155] Example 3

[0156] Preparation of the electrolytic cell framework: Weigh 0.6 g of YSZ powder and press it into a disc-shaped compact with a diameter of ~2 cm to form an electrolyte disc. Two microchannel-structured porous frameworks D3 obtained in Preparation Example 3 were bonded to the front and back of the disc using a YSZ-terpineol-ethyl cellulose binder. The resulting electrolyte disc was then calcined at 1250°C for 6 h to obtain the electrolytic cell framework A3.

[0157] Preparation of electrochemical reactor: According to the molecular formula La0.7 Sr 0.3 CoO 3-δ 0.07 mol of lanthanum nitrate, 0.03 mol of strontium nitrate, and 0.1 mol of cobalt nitrate were weighed in stoichiometric proportions and dissolved in 100 mL of deionized water. 0.2 mol of citric acid was added to obtain a mixed solution S3. 0.05 mol of Ni(NO3)2 was added to 60 mL of deionized water to fully dissolve it, and 0.06 mol of citric acid was added to obtain a mixed solution B3. 20 μL of mixed solution S3 was added to the microchannels on one side of the electrolytic cell skeleton A3 using a pipette and calcined at 1000°C for 2 hours. Then, ~40 μL of mixed solution B3 was added to the microchannels on both sides of the electrolytic cell skeleton A3 in two portions using a pipette (~20 μL added to each side) and calcined at 1000°C for 2 hours. The above impregnation-sintering steps were repeated until the cathode catalyst loading reached ~20 wt% of the total cathode mass and the anode catalyst loading reached ~25 wt% of the total anode mass, obtaining an electrochemical reactor C3. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterize the morphology and surface energy spectrum of the anode, and the results were similar to those in Figure 3. 0.7 Sr 0.3 CoO 3-δ The electrocatalyst and NiO thermal catalyst are evenly distributed on the inner wall of the pores formed by the YSZ, forming a continuous phase. The electrochemical reactor of this embodiment includes:

[0158] Electrolyte layer: The main component is YSZ, and the electrolyte layer has a dense structure with a porosity of <5%;

[0159] The thicknesses of the anode catalyst and cathode catalyst are 100 nm and 100 nm respectively;

[0160] The thickness of the electrolyte layer is 500 microns;

[0161] The mass ratio of the perovskite structure electrocatalyst to the metal oxide thermal catalyst is 1.4:1.

[0162] Example 4

[0163] Preparation of the electrolytic cell framework: Weigh 0.6 g of YSZ powder and press it into a disc-shaped compact with a diameter of ~2 cm to form an electrolyte disc. Two microchannel-structured porous frameworks D4 obtained in Preparation Example 4 were bonded to the front and back sides of the disc-shaped compact using a YSZ-terpineol-ethyl cellulose binder. The resulting electrolytic cell framework A4 was then calcined at 1380°C for 3 h.

[0164] Preparation of electrochemical reactor: According to the molecular formula La 0.6 Sr0.4 CoO 3-δ , 0.03 mol of lanthanum nitrate, 0.02 mol of strontium nitrate, and 0.05 mol of cobalt nitrate were weighed in stoichiometric ratios and dissolved in 60 mL of deionized water, and 0.1 mol of citric acid was added to obtain a mixed solution S3. 0.05 mol of Ni(NO3)2 was added to 50 mL of deionized water to fully dissolve it, and 0.05 mol of citric acid was added to obtain a mixed solution B3. 20 μL of mixed solution S3 was added to the microchannel on one side of the electrolytic cell skeleton A4 using a pipette and calcined at 800°C for 2 hours; then, ~40 μL of mixed solution B3 was added to the microchannels on both sides of the electrolytic cell skeleton A4 using a pipette (~20 μL added to each side) in two portions and calcined at 800°C for 2 hours. The above impregnation-sintering steps were repeated until the cathode catalyst loading reached ~30 wt% of the total cathode mass and the anode catalyst loading reached ~35 wt% of the total anode mass, obtaining an electrochemical reactor C4.

[0165] The electrochemical reactor of this embodiment includes:

[0166] Electrolyte layer: YSZ, which has a dense structure and a porosity of <5%;

[0167] The thicknesses of the anode catalyst and cathode catalyst are 100 nm and 150 nm respectively;

[0168] The thickness ratio of the anode support to the electrolyte layer is 6:1;

[0169] The mass ratio of the perovskite structure electrocatalyst to the metal oxide thermal catalyst is 1.1:1.

[0170] Example 5

[0171] An electrochemical reactor was prepared by the same method as in Example 1, except that vanadium nitrate was used instead of nickel nitrate to prepare the mixed solution B3, so that the thermal catalyst was VO2, and an electrochemical reactor C5 was obtained.

[0172] Example 6

[0173] The electrochemical reactor was prepared by the same method as in Example 1, except that the molar ratio of lanthanum nitrate to strontium nitrate in the mixed solution S3 was adjusted to 2:3, so that the prepared electrocatalyst had a perovskite structure La 0.4 Sr 0.6 CoO 3-δ , obtaining electrochemical reactor C6.

[0174] Comparative Example 1

[0175] An electrochemical reactor was prepared using the same method as in Example 1, except that the anode and cathode were commercially available products (the anode was LSCF powder from Ningbo Soforen Energy Technology Co., Ltd., and the cathode was nickelous oxide powder from Ningbo Soforen Energy Technology Co., Ltd.), both of which had no microchannel structure and were sponge-like porous structures, thereby obtaining an electrochemical reactor P1.

[0176] Comparative Example 2

[0177] An electrochemical reactor was prepared by the same method as in Example 1, except that the anode carrier and the cathode carrier were gadolinia-doped cerium oxide (GDC, purchased from Ningbo Suofuren Energy Technology Co., Ltd., brand GDC10), that is, the main component was gadolinia-doped cerium oxide, rather than yttria-stabilized zirconia, to obtain an electrochemical reactor P2.

[0178] Comparative Example 3

[0179] The electrochemical reactor was prepared in the same manner as in Example 1, except that the anode catalyst contained only La 0.6 Sr 0.4 CoO 3-δ , without loading any metal oxide thermal catalyst, to obtain the electrochemical reactor P3.

[0180] Comparative Example 4

[0181] The electrochemical reactor was prepared by the same method as in Example 1, except that the anode was prepared by conventional screen printing and had a conventional porous structure instead of a microchannel structure. The anode catalyst was La 0.6 Sr 0.4 CoO 3-δ A composition of an electrocatalyst and a NiO thermal catalyst, with a mass ratio of the two being 1.1:1; a cathode is manufactured by the same method as in Example 1, having a microchannel structure, and a loading amount of the cathode catalyst NiO being ~30wt% of the total mass of the cathode, to obtain an electrochemical reactor P4.

[0182] Test Example 1

[0183] The electrochemical reactor prepared in Example 1 was applied to the electrochemical reforming of methane / carbon dioxide to produce ethylene / carbon monoxide using the method shown in Figure 1. Specifically, a hydrogen / nitrogen / carbon dioxide mixture was introduced into the cathode of the electrochemical reactor, with inlet gas flow rates of 5 mL / min hydrogen, 35 mL / min nitrogen, and 30 mL / min carbon dioxide, respectively; a methane / nitrogen mixture was introduced into the anode, with inlet gas flow rates as shown in Table 1. At 850°C, the current density was 100 mA / cm 2The electrolysis reaction was carried out under the condition of 100 mA / cm2. The tail gas produced by the anode was collected by air bag and its components were analyzed by chromatography. The results are shown in Figure 8 and Table 1. At 850 °C, the current density was 100 mA / cm2. 2 and 300mA / cm 2 Electrolysis reactions were carried out under the following conditions, and the tail gases produced by the cathodes were collected by air bags. The components were analyzed by chromatography, and the results are shown in Figure 9 and Table 2.

[0184] The electrolytic cell impedance spectrum and current-voltage curve results of the electrochemical reactor prepared in Example 1 are shown in Figures 6 and 7, respectively.

[0185] Table 1

[0186] The results show that when the inlet gas flow rates are 2 mL / min of methane and 72 mL / min of nitrogen, the ethylene selectivity in the anode gas product is the highest, reaching 84.90%. The anode ethylene production reaches 0.0553 mL / min. Compared with the theoretical anode production, the calculated anode Faradaic efficiency reaches 52.93%. Further analysis in Figure 6 shows that under high space velocity conditions (total inlet gas flow rate ≥ 40 mL / min), only ethylene and ethane are detected in the product, with no over-oxidation products such as CO and CO2. These results demonstrate that this reactor primarily produces C2 products during high-temperature electrocatalytic oxidation of methane, with extremely high olefin selectivity, demonstrating its potential for scale-up applications.

[0187] Table 2

[0188] From the results in Table 2, we can see that under this condition, when the current density is 100mA / cm 2 The CO production at the outlet is 2.01 mL / min, of which 1.88 mL / min is generated by the reverse water gas shift reaction and 0.21 mL / min is generated by the electrochemical reaction. The theoretical electrochemical CO production at this current density is 0.23 mL / min, and the Faraday efficiency is 91%. When the current density is 300 mA / cm 2 When the Faraday efficiency of electrolyzing CO2 to CO is 100%, it should be noted that due to the scale limitation of the electrochemical reactor, the amount of CO obtained by electrochemical conversion is very small, so the calculation of the Faraday efficiency has a certain error. However, the overall results show that the reactor has a very high Faraday efficiency when catalyzing the conversion of CO2 to CO. The electrochemical reactor of Example 1 is 850℃ and 100mA / cm 2 The results of the electrolytic methane operation stability test under different current densities are shown in Figure 10.

[0189] Test Example 2

[0190] A hydrogen / nitrogen / carbon dioxide mixture was introduced into the cathode of each electrochemical reactor described in Examples 2-6 and Comparative Examples 1-4, with inlet gas flow rates of 5 mL / min hydrogen, 35 mL / min nitrogen, and 30 mL / min carbon dioxide, respectively; a methane / nitrogen mixture was introduced into the anode, with inlet gas flow rates as shown in Table 3. At 850°C, the current density was 100 mA / cm 2 The electrolysis reaction was carried out under the condition of 100 nm, and the tail gas produced by the anode was collected by an air bag. Its components were analyzed by chromatography. The results are shown in Table 3.

[0191] Table 3

[0192] Table 3

[0193] Table 3

[0194] It can be seen from the results in Table 3 that, compared with comparative examples 1-4, the electrochemical reactors C1-C6 prepared in Examples 1-6 of the technical solution of the present invention have the beneficial effects of higher C2 and ethylene selectivity and higher Faraday efficiency in the reaction of methane / carbon dioxide electrochemical reforming to ethylene / carbon monoxide.

[0195] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple variations and combinations should also be considered as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. An electrochemical reactor with the function of electrochemical reforming methane / carbon dioxide to produce ethylene / carbon monoxide, the electrochemical reactor comprising an anode and a cathode and an electrolyte layer disposed between the anode and the cathode, the anode comprising an anode support and an anode catalyst attached to the anode support, the cathode comprising a cathode support and a cathode catalyst attached to the cathode support, and the main components of the anode support and the cathode support are each independently yttria-stabilized zirconia, characterized in that: The anode carrier and the cathode carrier each have a microchannel structure; the anode catalyst includes a perovskite structure electrocatalyst and a metal oxide MO n thermal catalysts; M is at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Mo, Ru, Sn, Ce, and Pr; 1≤n≤3.

2. The electrochemical reactor according to claim 1, wherein The closed-pore ratio of the microchannel structures of the cathode and the anode is 0-5%, preferably 0-1%.

3. The electrochemical reactor according to claim 1 or 2, wherein: The microchannel structures of the cathode and the anode are both layered pores, and the aspect ratio of the pore cross section is 1-20:1, preferably 1-10:

1.

4. The electrochemical reactor according to any one of claims 1 to 3, wherein: The average pore size of the pores of the microchannel structures of the cathode and the anode at one end away from the electrolyte layer in the length direction is 2-300 microns, preferably 2-200 microns; the average pore size in the width direction is 2-30 microns, preferably 2-20 microns.

5. The electrochemical reactor according to any one of claims 1 to 4, wherein: The thickness of the anode support and the anode support are independently 100-2000 microns, preferably 100-800 microns; the thickness of the electrolyte layer is 400-500 microns.

6. The electrochemical reactor according to any one of claims 1 to 5, wherein: The anode catalyst and cathode catalyst are each uniformly distributed as a continuous phase within the microchannel structure of the anode support and cathode support; preferably, the thickness of the anode catalyst and cathode catalyst is each 100-500 nm.

7. The electrochemical reactor according to any one of claims 1 to 6, wherein: The content of the anode catalyst is 10-60 wt% based on the total mass of the anode; Preferably, the perovskite structure electrocatalyst and the metal oxide MO n The mass ratio of the thermal catalyst is 0.5-2:1; preferably 1-1.5:

1.

8. The electrochemical reactor according to any one of claims 1 to 7, wherein: The perovskite structure electrocatalyst includes rare earth elements, alkaline earth metal elements, Group VIII elements and oxygen elements, preferably including La, Sr, Co and O elements; more preferably, the perovskite structure electrocatalyst is La 1-x Sr x CoO 3-δ ; where 0 <x≤0.5,0≤δ≤0.5; The cathode catalyst is at least one of NiO, CuO and CeO2, and the content of the cathode catalyst is 30-60 wt% based on the total mass of the cathode.

9. The electrochemical reactor according to any one of claims 1 to 8, wherein: The perovskite structure electrocatalyst is located in the metal oxide MO n between the hot catalyst and the anode support.

10. The electrochemical reactor according to any one of claims 1 to 9, wherein: The electrolyte layer is composed of yttria-stabilized zirconia, and the porosity of the electrolyte layer is less than 5%.

11. Use of the electrochemical reactor according to any one of claims 1 to 10 in the electrochemical reforming of methane / carbon dioxide to produce ethylene / carbon monoxide.

12. A method for producing ethylene and carbon monoxide by electrochemical reforming of methane and carbon dioxide, the method comprising: introducing a carbon dioxide-containing gas into the cathode of the electrochemical reactor according to any one of claims 1 to 10, introducing a methane-containing gas into the anode under electrolysis reaction conditions, and collecting the obtained ethylene gas and carbon monoxide gas.

13. The method according to claim 12, wherein: The electrolysis reaction conditions include: temperature of 600-900°C, gas flow rate of 10-200 mL / min / cm 2 , current density is 10-1000mA / cm 2 .

14. A catalyst, characterized in that The catalyst includes a perovskite structure electrocatalyst and a metal oxide MO n thermal catalysts; M is at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Mo, Ru, Sn, Ce, and Pr; 1≤n≤3.

15. The catalyst according to claim 14, wherein The perovskite structure electrocatalyst includes rare earth elements, alkaline earth metal elements, Group VIII elements and oxygen elements, preferably including La, Sr, Co and O elements; more preferably, the perovskite structure electrocatalyst is La 1-x Sr x CoO 3-δ ; where 0 <x≤0.5,0≤δ≤0.5; Preferably, the perovskite structure electrocatalyst and the metal oxide MO n The mass ratio of the thermal catalyst is 0.5-2:1; preferably 1-1.5:

1.

16. Use of the catalyst according to claim 14 or 15 in an electrochemical reactor.

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