CN224119123U - Carbon dioxide electrocatalytic reactor - Google Patents

Abstract

The utility model relates to a carbon dioxide electrocatalytic reactor, which comprises an anode chamber, a cathode chamber, a functional layer and an anion exchange layer, wherein water-containing liquid is introduced into the anode chamber, a mixed gas containing carbon dioxide and water is introduced into the cathode chamber, the functional layer separates the anode chamber from the cathode chamber, the functional layer comprises a cathode catalytic layer positioned at one side of the cathode chamber and an anode catalytic layer positioned at one side of the anode chamber, and the anion exchange layer is arranged between the anode catalytic layer and the cathode catalytic layer. The carbon dioxide electrocatalytic reactor reduces the mass transfer resistance of the functional layer by improving the functional layer, so that the reaction rate and the reaction efficiency of the reactor can be improved, and the conversion rate of a reaction system is improved. The functional layer of the multilayer film in the prior art is simplified into a single ion exchange film and a two-chamber structure is formed, so that the structure of the functional layer is simplified, and the aim of reducing mass transfer resistance is fulfilled.

Description

Carbon dioxide electrocatalytic reactor

Technical Field

The utility model relates to the technical field of carbon dioxide electrocatalytic reduction, in particular to a carbon dioxide electrocatalytic reactor.

Background

Under the condition that climate change and greenhouse effect are more and more focused, the carbon dioxide fixing technology is a technology with great potential for reducing carbon emission, controlling the greenhouse effect and coping with the climate change. Electrocatalytic conversion of carbon dioxide is one of the known efficient technological routes to achieve carbon dioxide capture immobilization. The carbon dioxide is converted into other organic finished products through electrolytic reduction, so that carbon fixation is realized.

The applicant has filed a chinese patent application No. 2023104783353 entitled carbon dioxide electrocatalytic reactor, which proposes a carbon dioxide electrocatalytic reactor having a two-chamber structure separated by a multi-layer functional membrane. Although it primarily achieves the fixation of carbon dioxide conversion, the effect is not ideal. Due to the existence of the multi-layer functional film structure, electron transport can be blocked, and the overall reaction rate is compromised. And in long-term application, the performance of the functional film is degraded, which further leads to a decrease in the carbon fixation efficiency of the reaction apparatus.

Disclosure of utility model

In view of the problems that the ionic transport is blocked and the conversion rate and efficiency are difficult to effectively maintain and improve due to the multilayer film structure in the existing carbon dioxide electrocatalytic reactor, the utility model provides the carbon dioxide electrocatalytic reactor.

The application provides a carbon dioxide electrocatalytic reactor, comprising:

An anode chamber into which an aqueous liquid is introduced;

A cathode chamber, wherein a mixed gas containing carbon dioxide and water is introduced into the cathode chamber;

The functional layer separates the anode chamber and the cathode chamber, comprises a cathode catalytic layer positioned at one side of the cathode chamber, an anode catalytic layer positioned at one side of the anode chamber, and an anion exchange layer between the anode catalytic layer and the cathode catalytic layer.

Preferably, the functional layer further comprises an ion exchange resin formed between the anode catalytic layer and the anion exchange layer, or the ion exchange resin is formed between the cathode catalytic layer and the anion exchange layer.

Preferably, the functional layer further comprises an ion exchange resin formed between the anode catalytic layer and the anion exchange layer, and the ion exchange resin is formed between the cathode catalytic layer and the anion exchange layer.

Preferably, the anode catalytic layer is a titanium felt substrate with anode catalyst supported on the surface.

Preferably, the cathode catalytic layer is gas diffusion type carbon paper with a cathode catalyst supported on the surface.

Preferably, the aqueous liquid introduced into the anode chamber is pure water.

Preferably, the aqueous liquid introduced into the anode chamber is an aqueous formate solution.

The carbon dioxide electrocatalytic reactor reduces the mass transfer resistance of the functional layer by improving the functional layer, so that the reaction rate and the reaction efficiency of the reactor can be improved, and the conversion rate of a reaction system is improved. The functional layer of the multilayer film in the prior art is simplified into a single ion exchange film and a two-chamber structure is formed, so that the structure of the functional layer is simplified, and the aim of reducing mass transfer resistance is fulfilled. The transport resistance of the functional layer to ions is reduced, and meanwhile, the accumulation of ions at the anode catalytic layer and the cathode catalytic layer is reduced, so that the activity time of the anode catalytic layer and the cathode catalytic layer is prolonged, and the interval period required for activating the catalyst activity is prolonged.

Drawings

FIG. 1 is a schematic diagram of a carbon dioxide electrocatalytic reactor of the present utility model.

In the figure:

1, anode chamber, 2, cathode chamber, 3, functional layer, 31, anode catalytic layer, 32, ion exchange resin, 33, anion exchange layer and 35, cathode catalytic layer.

Detailed Description

The present utility model will be described in detail below with reference to the drawings and the specific embodiments, and in the present specification, the dimensional proportion of the drawings does not represent the actual dimensional proportion, but only represents the relative positional relationship and connection relationship between the components, and the components with the same names or the same reference numerals represent similar or identical structures, and are limited to the schematic purposes.

FIG. 1 is a schematic diagram of a carbon dioxide electrocatalytic reactor of the present application. The reactor first comprises an anode compartment 1 and a cathode compartment 2 separated by a functional layer 3. In use, an aqueous liquid, which may be pure water or an aqueous solution of certain salts, is introduced into the anode compartment 1. Since formic acid is produced at the anode, the aqueous liquid introduced into the anode chamber 1 may be pure water in order to ensure simple and easy handling of the components of the product solution. The aqueous liquid may also be formate, in which case the anions in the output liquid from the anode compartment 1 are still formate ions only, so that the subsequent purification operation can be conveniently carried out. The aqueous solution of the specific salt injected into the anode chamber 1 is mainly for the purpose of improving the conductivity of the liquid in the anode chamber. Anionic salts other than formate can be introduced into the anode compartment 1, but are generally not preferred because of the introduction of impurity anions, which are generally detrimental to subsequent purification treatments. Inside the cathode chamber 2 of the reactor, a mixed gas containing carbon dioxide and water, such as humidified carbon dioxide gas, is introduced.

The functional layer 3 is a multilayer film structure including at least an anode catalytic layer 31 on the anode chamber 1 side, a cathode catalytic layer 35 on the cathode chamber 2 side, and an anion exchange layer 33 interposed between the anode catalytic layer 31 and the cathode catalytic layer 35. Generally, on the cathode catalytic layer 35, a mixture containing carbon dioxide and water undergoes a reduction reaction to produce formate. On the anode catalytic layer 31, water molecules are oxidized to generate hydrogen ions. Carbonate enters the anode compartment 1 through the anion exchange layer 33, forming a formic acid solution system in the anode compartment 1. In this technical solution, there is no multi-layer ion membrane structure disposed between the two chambers, but only an anion exchange membrane is present, and no further cation exchange membrane is required. Because the mass transfer resistance of the ion exchange membrane to ion transport is relatively large, the ion flow speed and efficiency between the anode chamber 1 and the cathode chamber 2 are obviously improved under the condition that the cation exchange membrane is eliminated. In this case, the reaction speed and reaction efficiency of the reactor will be improved.

The anode catalyst layer 31 in the functional layer 3 is typically a catalyst-supporting anode titanium felt. The titanium felt is formed by adopting oxides and hybrids containing iridium, iron, cobalt, nickel, copper and molybdenum on a titanium felt substrate through a high-temperature sintering method. The cathode catalyst layer 35 in the functional layer 3 is typically a catalyst-supporting cathode carbon paper. The catalyst is obtained by spraying a uniformly mixed catalyst solution on gas diffusion type carbon paper, wherein the catalyst is selected from metal nano arrays containing metal bismuth, tin, antimony and indium, alloys, metal oxides, sulfides and the like. The cathode catalyst, the solvent and the nafion solution can be mixed by ultrasonic to obtain uniform spraying solution.

In fact, due to the problem of the bonding between the anode catalytic layer 31, the cathode catalytic layer 35 and the anion exchange layer 33, the ions obtained by electrolysis on the anode catalytic layer 31 and the cathode catalytic layer 35 do not come into direct contact with the anion exchange layer 33, which likewise leads to an increase in mass transfer resistance. Specifically, in the anode pure water system, the ions ionized on the anode catalytic layer 31 need to reach the anion exchange layer 33 after being transported by the pure water medium, resulting in a large ion transport resistance. The same problem also exists in the cathode chamber 2. In order to reduce mass transfer resistance of the system and improve reaction efficiency of the system, it may be preferable to provide the ion exchange resin 32 on at least one side of the anion exchange layer 33.

A layer of ion exchange resin 32 may be disposed between the anode catalytic layer 31 and the anion exchange layer 33 such that both side surfaces of the ion exchange resin 32 are in contact with the anode catalytic layer 31 and the anion exchange layer 33, respectively, so that ions generated on the anode catalytic layer 31 can pass through the ion exchange resin 32 to the large anion exchange layer 33 under sufficient contact at the interface, thereby achieving the purpose of reducing ion transport resistance. Similarly, the ion exchange resin 32 may be disposed not only between the anode catalyst layer 31 and the anion exchange layer 33 but also between the anion exchange layer 33 and the cathode catalyst layer 35 to reduce ion transport resistance between the cathode catalyst layer 35 and the anion exchange layer 33 in the cathode chamber 2. The ion exchange resin 32 can significantly increase the reaction rate and efficiency because it reduces the ion transport resistance of the system. On the basis, the anode and cathode products can be transported in time, so that the accumulation at the polar plate and the catalyst layer is reduced, the activity time of the corresponding catalyst layer is prolonged, and the interval period required for reactivating the functional film is prolonged.

Current electrocatalytic carbon dioxide cells have a low general lifetime and can operate stably for a short period of time, which may be a result of the relatively complex internal structure of the cells and limitations in material lifetime. In the common electrocatalytic conversion process of carbon dioxide, an anion-cation exchange membrane, a specific electrolyte solution and the like are required to be used as ion exchange channels in a reactor, however, the mass transfer resistance of the mediums is relatively high, and the energy conversion efficiency of the reaction is relatively low.

In order to solve the technical problem of the existing carbon dioxide catalytic electrolytic cell, the technical method adopts a cell structure with a simpler structure, only adopts an anode-cathode catalyst and an anion exchange membrane, only carbon dioxide and water participate in the whole reaction process, and the anion membrane and the anode-cathode catalyst are in direct contact, so that the mass transfer resistance is reduced, formic acid products are directly produced from the anode, and the product collection is convenient. And the relatively simple electrolytic cell structure can improve the overall stability of the performance of the electrolytic cell, and facilitate the long-time operation of the electrolytic cell, the assembly of the electrolytic cell and the replacement of materials.

The attached table is the test data of the carbon dioxide electrolytic cell manufactured by the structure and the functional materials under the standard working condition. It can be determined that the carbon dioxide electrocatalytic reactor with the two-chamber structure can stably run for a long time under the action of the activation system of the electrolytic cell, the continuous working time can reach more than 1294 hours, the Faraday efficiency can be stabilized at a relatively high value, and the conversion efficiency of the reaction is higher.

The attached table:

The foregoing is merely illustrative of the preferred embodiments of the present utility model and is not intended to limit the scope of the utility model, and various modifications and improvements made by those skilled in the art to which the utility model pertains will fall within the scope of the utility model as defined by the appended claims without departing from the spirit of the utility model.

Claims (7)

1. A carbon dioxide electrocatalytic reactor, characterized in that it comprises: Anode chamber (1), wherein an aqueous liquid is introduced; A cathode chamber (2) is introduced into which a mixed gas containing carbon dioxide and water is introduced; The functional layer (3) separates the anode chamber (1) and the cathode chamber (2). The functional layer (3) includes a cathode catalyst layer (35) located on one side of the cathode chamber (2) and an anode catalyst layer (31) located on one side of the anode chamber (1). It also has an anion exchange layer (33) between the anode catalyst layer (31) and the cathode catalyst layer (35). 2. The carbon dioxide electrocatalytic reactor according to claim 1, wherein the functional layer (3) further comprises an ion exchange resin (32); the ion exchange resin (32) is formed between the anode catalyst layer (31) and the anion exchange layer (33), or the ion exchange resin (32) is formed between the cathode catalyst layer (35) and the anion exchange layer (33). 3. The carbon dioxide electrocatalytic reactor according to claim 1, wherein the functional layer (3) further comprises an ion exchange resin (32); the ion exchange resin (32) is formed between the anode catalyst layer (31) and the anion exchange layer (33), and the ion exchange resin (32) is formed between the cathode catalyst layer (35) and the anion exchange layer (33). 4. The carbon dioxide electrocatalytic reactor according to any one of claims 1-3, characterized in that the anode catalyst layer (31) is a titanium felt substrate with anode catalyst supported on its surface. 5. The carbon dioxide electrocatalytic reactor according to any one of claims 1-3, characterized in that the cathode catalyst layer (35) is a gas diffusion type carbon paper with a cathode catalyst supported on its surface. 6. The carbon dioxide electrocatalytic reactor according to any one of claims 1-3, characterized in that the aqueous liquid introduced into the anode chamber (1) is pure water. 7. The carbon dioxide electrocatalytic reactor according to any one of claims 1-3, characterized in that the aqueous liquid introduced into the anode chamber (1) is an aqueous solution of formate.