Asymmetric PEM Electrolysis System and Method

Abstract

This invention belongs to the field of electrochemical synthesis and hydrogen energy technology, and discloses an asymmetric PEM electrolysis system and method. The asymmetric PEM electrolysis system includes an anode chamber, a cathode chamber, a proton exchange membrane, and an anode catalyst. The proton exchange membrane is disposed between the anode chamber and the cathode chamber, and the anode catalyst is disposed in the anode chamber. The anode catalyst is a catalyst with a CoO-Co3O4 heterostructure. This invention can effectively suppress the over-oxidation reaction caused by the participation of water molecules, suppress the competition for oxygen evolution reaction, and also avoid the dissolution of metal catalysts in an alkaline environment.

Description

Technical Field

[0001] This invention relates to the fields of electrochemical synthesis and hydrogen energy technology, specifically to an asymmetric PEM electrolysis system and method. Background Technology

[0002] Alcohol oxidation-assisted hydrogen production (HWE) is a technology that uses electrochemical methods to convert alcohol molecules into high-value-added chemicals such as aldehydes and simultaneously generate hydrogen. This process has a lower theoretical potential than traditional water electrolysis, and therefore has attracted widespread attention.

[0003] Currently, alcohol oxidation-assisted hydrogen production is typically carried out in alkaline or neutral aqueous electrolyzers. Existing technologies employ conventional alkaline electrolytes (such as KOH solution) or symmetrical aqueous acidic proton exchange membrane (PEM) electrolyzers, with anode catalysts often using commercially available single-phase metal oxides (such as Co3O4) or noble metal catalysts (such as Pd / C). However, these existing methods have the following problems in practical applications: First, at industrial-grade current densities (>100 mA / cm²), aldehydes, the anode products, are prone to over-oxidation, further converting into organic acids or carbonates, leading to a significant decrease in the selectivity of the target product (for example, aldehydes generated under alkaline conditions will rapidly undergo Cannizzaro disproportionation), increasing the difficulty of product separation and reducing the process economy. Second, in alkaline or neutral environments, competition for the oxygen evolution reaction (OER) is intense, and the metal catalyst is prone to dissolution, significantly reducing the Faraday efficiency of partial oxidation to aldehydes, making it difficult to achieve both high activity and high selectivity.

[0004] Therefore, the aldehydes produced by the anode in the existing technology are prone to over-oxidation, the oxygen evolution reaction (OER) is highly competitive, and the problem of metal catalysts being easily dissolved in alkaline environments urgently needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide an asymmetric PEM electrolysis system and method. This invention can effectively suppress the excessive oxidation reaction caused by the participation of water molecules, suppress the competition of oxygen evolution reaction, and at the same time avoid the dissolution of metal catalysts in alkaline environment.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides an asymmetric PEM electrolysis system, comprising: The anode chamber is used to contain a pure alcohol solution; The cathode chamber is used to contain an aqueous acidic electrolyte. A proton exchange membrane is disposed between the anode chamber and the cathode chamber to isolate the pure alcohol solution from the aqueous acidic electrolyte and to conduct protons, thereby forming an asymmetric reaction environment. An anode catalyst is disposed in the anode chamber, and the anode catalyst is a catalyst having a CoO-Co3O4 heterostructure.

[0007] In some embodiments, the catalyst having a CoO-Co3O4 heterostructure is supported on a carbon felt.

[0008] In some embodiments, the proton exchange membrane is a perfluorosulfonic acid membrane.

[0009] In some embodiments, a cathode catalyst is disposed in the cathode chamber, and the cathode catalyst is platinum-carbon, platinum black, or a transition metal hydrogen evolution catalyst.

[0010] Secondly, the present invention provides an asymmetric PEM electrolysis method, based on the aforementioned asymmetric PEM electrolysis system, comprising the following steps: A pure alcohol solution is introduced into the anode chamber, and an aqueous acidic electrolyte is introduced into the cathode chamber. When an electric current is applied, the pure alcohol solution in the anode chamber undergoes a partial oxidation reaction under the action of the CoO-Co3O4 heterogeneous interface catalyst to generate aldehyde products. At the same time, protons are released, which migrate through the proton exchange membrane to the cathode chamber and are reduced to generate hydrogen gas on the cathode surface, thus completing the PEM electrolysis.

[0011] In some embodiments, the pure alcohol solution is a benzyl alcohol solution, and the aldehyde product is benzaldehyde.

[0012] In some embodiments, the density of the applied current is 100-500 mA / cm², and the temperature of the applied current is 20-80°C.

[0013] In some embodiments, the density of the applied current is 2 mA / cm².

[0014] In some embodiments, the molar ratio of CoO to Co3O4 in the CoO-Co3O4 heterostructure catalyst is (1-10):(1-10).

[0015] In some embodiments, the flow rate of the pure alcohol solution is 1-20 mL / min, and the flow rate of the aqueous acidic electrolyte is 1-50 mL / min.

[0016] The above technical solution has the following advantages or beneficial effects: Firstly, this invention provides an asymmetric PEM electrolysis system. By setting up an anode chamber containing a pure alcohol solution and a cathode chamber containing an aqueous acidic electrolyte, physically separating the two by a proton exchange membrane, an asymmetric reaction environment is formed. This effectively suppresses over-oxidation caused by water molecules and avoids the dissolution problem of metal catalysts in an alkaline environment. The anode chamber employs a catalyst with a CoO-Co3O4 heterostructure. This interface significantly lowers the energy barrier of the rate-determining step (proton-coupled electron transfer) in the oxidation of alcohol to aldehydes by regulating the electronic structure, thereby suppressing competition from the oxygen evolution reaction. Therefore, this system can achieve highly selective partial oxidation of alcohols to aldehydes at industrial-grade current densities, while simultaneously producing hydrogen at the cathode. It combines high Faradaic efficiency with excellent stability, solving the problems of easy over-oxidation of aldehydes, low selectivity, and easy catalyst deactivation in existing technologies.

[0017] In some embodiments, CoO will be used A catalyst with a Co3O4 heterostructure interface is supported on a carbon felt. The porous three-dimensional network structure and high conductivity of the carbon felt significantly increase the catalyst's dispersion area and reactive sites, while simultaneously promoting mass transfer of the pure alcohol solution within the anode chamber. This setup further enhances the reaction rate and Faraday efficiency of the partial oxidation of alcohols to aldehydes, helping to maintain stable high selectivity at high current densities.

[0018] In some embodiments, a perfluorosulfonic acid membrane is used as the proton exchange membrane. Its excellent chemical stability and mechanical strength enable it to withstand long-term corrosion from aqueous acidic electrolytes while maintaining high proton conduction efficiency. This membrane effectively isolates the pure alcohol solution at the anode from the acidic electrolyte at the cathode, preventing cross-contamination and ensuring the stable operation of the asymmetric reaction environment. This, in turn, guarantees the continuous reliability of highly selective oxidation of alcohols to aldehydes and efficient hydrogen evolution at the cathode.

[0019] In some embodiments, placing a platinum-carbon, platinum-black, or transition metal hydrogen evolution catalyst in the cathode chamber can provide highly active reaction sites for proton reduction, significantly reduce the hydrogen evolution overpotential, and thereby improve the Faraday efficiency of hydrogen production at the cathode. The above catalysts, along with the anode CoO... The synergistic effect of the Co3O4 catalyst enables the entire electrolysis system to achieve stable coupling between selective oxidation at the anode and efficient hydrogen evolution at the cathode under an asymmetric architecture, and the catalyst type can be flexibly selected according to cost and activity requirements.

[0020] Secondly, the present invention provides an asymmetric PEM electrolysis method, which isolates the pure alcohol solution from the acidic electrolyte and uses CoO2. A Co3O4 catalyst enables highly selective partial oxidation of alcohols to aldehydes at the anode, while protons migrate across the membrane to the cathode for reduction to hydrogen. This method effectively suppresses competition between aldehyde over-oxidation and the oxygen evolution reaction, and can operate stably at industrial-grade current densities, combining high selectivity, high Faraday efficiency, and low energy consumption.

[0021] In some embodiments, benzyl alcohol solution is used as the reaction substrate, which can be converted to benzaldehyde with high selectivity in the asymmetric PEM electrolysis system of this application. Benzaldehyde is an important fine chemical intermediate. This method effectively suppresses the Cannizzaro disproportionation reaction and the side reaction of excessive oxidation to benzoic acid that easily occur in benzyl alcohol under alkaline conditions. It can achieve a benzaldehyde selectivity of more than 95% at industrial-grade current densities, significantly improving the process economy and product purity.

[0022] In some embodiments, the applied current density is controlled at 100 500 mA / cm², temperature controlled at 20 At 80℃, the electrolysis system of this application can operate stably under industrial-grade high loads. This parameter range balances the kinetics of alcohol oxidation reaction and mass transfer efficiency, ensuring both the optimal CoO content and the optimal efficiency of mass transfer. The Co3O4 catalyst exhibits high selectivity for aldehyde products (>95%) while maintaining Faraday efficiency (>90%), and avoids exacerbating side reactions or increasing energy consumption.

[0023] In some embodiments, the applied current density is set to 2 mA / cm², suitable for fine electrosynthesis scenarios at lower current densities, under which the anodic reaction kinetics are stable and CoO Co3O4 catalysts can more precisely control the proton-coupled electron transfer process, further suppressing side reactions and obtaining aldehyde products with higher purity. At the same time, the cathode hydrogen evolution is stable, and the overall system energy consumption is low, making it suitable for the preparation of small batches of high-value-added chemicals.

[0024] In some embodiments, controlling the molar ratio of CoO to Co3O4 within the range of (1-10):(1-10) allows for flexible adjustment of the density and electronic structure of the heterointerface, thereby optimizing the selectivity of the catalyst for the alcohol oxidation reaction pathway. This ratio range balances the exposure of interfacial active sites with the stability of the catalyst, ensuring that in an asymmetric PEM electrolysis system, both high selectivity for aldehyde products and ideal reaction rates and Faraday efficiency are maintained.

[0025] In some embodiments, controlling the flow rate of the pure alcohol solution at 1-20 mL / min and the flow rate of the aqueous acidic electrolyte at 1-50 mL / min allows for precise control of the residence time and mass transfer efficiency of the reactants in the anode chamber, timely removal of generated aldehyde products, and prevention of excessive oxidation. Simultaneously, sufficient electrolyte flow on the cathode side maintains stable proton conduction and hydrogen evolution rates. This flow rate range balances high selectivity, high Faraday efficiency, and reliable continuous system operation. Detailed Implementation

[0026] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the description is considered to be exemplary in nature and not restrictive.

[0027] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0029] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] In the field of alcohol oxidation-assisted hydrogen production (HWE) technology, although the process has thermodynamic advantages, a serious trade-off exists between activity and selectivity in practical applications. Especially at industrial-grade current densities (e.g., above 100 mA / cm²), over-oxidation reactions easily occur at the anode, leading to the further conversion of the target product aldehydes into organic acids or carbonates. This not only increases the difficulty of product separation but also significantly reduces the process's economics. Furthermore, in traditional alkaline or neutral aqueous electrolyzers, competition from the oxygen evolution reaction (OER) and the dissolution of metal catalysts in alkaline environments severely limit the efficiency of partial oxidation of alcohols to aldehydes.

[0033] Based on the above background, this application provides an asymmetric PEM electrolysis system, the core of which includes: an anode chamber, a cathode chamber, a proton exchange membrane, and an anode catalyst; the anode chamber is used to contain a pure alcohol solution; the cathode chamber is used to contain an aqueous acidic electrolyte; the proton exchange membrane is disposed between the anode chamber and the cathode chamber to isolate the pure alcohol solution from the aqueous acidic electrolyte and conduct protons, forming an asymmetric reaction environment; the anode catalyst is disposed in the anode chamber, and the anode catalyst is a catalyst with a CoO-Co3O4 heterostructure.

[0034] This application achieves beneficial effects through the synergistic effect of an asymmetric reaction environment and interfacial catalysis: On the one hand, the proton exchange membrane physically isolates the pure alcohol solution at the anode from the acidic aqueous electrolyte at the cathode. The anhydrous environment on the anode side fundamentally inhibits excessive oxidation reactions involving water molecules (such as aldehyde-acid reactions). Simultaneously, the acidic medium prevents the Cannizzaro disproportionation reaction of aldehydes under alkaline conditions and prevents the dissolution of the metal catalyst; on the other hand, CoO... The Co3O4 heterointerface significantly lowers the energy barrier of the rate-determining step (proton-coupled electron transfer, PCET) in the oxidation of alcohols to aldehydes by modulating the electronic structure, thereby accelerating the target reaction pathway and suppressing competition from the oxygen evolution reaction. As a result, the system combines high selectivity (>95%), high Faraday efficiency (>90%), and low electrolysis voltage at industrial-grade current densities.

[0035] Example 1: This invention provides an asymmetric PEM electrolysis system, the core of which includes: an anode chamber, a cathode chamber, a proton exchange membrane, and an anode catalyst; the anode chamber is used to contain a pure alcohol solution; the cathode chamber is used to contain an aqueous acidic electrolyte; the proton exchange membrane is disposed between the anode chamber and the cathode chamber to isolate the pure alcohol solution from the aqueous acidic electrolyte and conduct protons, forming an asymmetric reaction environment, which can effectively inhibit the excessive oxidation of alcohols caused by water molecules participating in the anode reaction, while preventing the dissolution of the metal catalyst in the acidic environment; the anode catalyst is disposed in the anode chamber, and the anode catalyst is a catalyst with a CoO-Co3O4 heterostructure.

[0036] In some embodiments, the catalyst with a CoO-Co3O4 heterostructure can significantly reduce the energy barrier of the first proton-coupled electron transfer (PCET) step in the oxidation of alcohols to aldehydes by regulating the electronic structure through the interface formed between CoO and Co3O4. By employing the above catalyst, the system of this embodiment can accelerate the target reaction pathway and suppress side reactions at high current densities.

[0037] In some embodiments, through the combined effects of the pure alcohol environment in the anode chamber, the aqueous acidic environment in the cathode chamber, and the anode catalyst with a CoO-Co3O4 heterostructure, the system can achieve highly selective partial oxidation of alcohols to aldehydes at industrial-grade current densities, while simultaneously generating hydrogen at the cathode, effectively suppressing over-oxidation of aldehyde products and competition from the oxygen evolution reaction.

[0038] In some embodiments, the catalyst having a CoO-Co3O4 heterostructure can be supported on a carbon felt. The carbon felt, as a porous conductive support, provides a large specific surface area, which is beneficial for catalyst dispersion and reactant mass transfer, further improving the anodic reaction efficiency.

[0039] In some embodiments, the proton exchange membrane may be a perfluorosulfonic acid membrane (e.g., a Nafion membrane). Perfluorosulfonic acid membranes have excellent proton conductivity and chemical stability, enabling them to operate stably in acidic media for extended periods and effectively isolate the reaction solutions in the anode and cathode chambers.

[0040] In some embodiments, a cathode catalyst is disposed within the cathode chamber. This cathode catalyst can be platinum-carbon, platinum black, or a transition metal hydrogen evolution catalyst. The cathode catalyst is used to accelerate the proton reduction reaction to generate hydrogen, thereby improving the Faraday efficiency of hydrogen production at the cathode.

[0041] This embodiment provides an asymmetric PEM electrolysis method, which, based on the asymmetric PEM electrolysis system, includes the following steps: Step 1: Pass a pure alcohol solution into the anode chamber and a water-based acidic electrolyte into the cathode chamber.

[0042] In some embodiments, the pure alcohol solution can be a benzyl alcohol solution, and the corresponding aldehyde product is benzaldehyde. The partial oxidation of benzyl alcohol to benzaldehyde is a typical selective oxidation reaction of alcohols, which can effectively inhibit the further oxidation of benzaldehyde to benzoic acid or the occurrence of disproportionation reaction.

[0043] Step 2: Apply current. In the anode chamber, the pure alcohol solution undergoes a partial oxidation reaction under the action of the CoO-Co3O4 heterogeneous interface catalyst to generate aldehyde products. At the same time, protons are released. The protons migrate through the proton exchange membrane to the cathode chamber and are reduced to generate hydrogen gas on the cathode surface, thus completing PEM electrolysis. This achieves the coupling of selective oxidation of alcohols to aldehydes at the anode and hydrogen evolution at the cathode. Moreover, the anode reaction replaces the oxygen evolution reaction in traditional water electrolysis, significantly reducing the energy consumption of electrolysis.

[0044] In some embodiments, the applied current density can be 100-500 mA / cm², and the applied current temperature can be 20-80°C. Within the above parameter range, the system can maintain high selectivity and Faraday efficiency.

[0045] In some embodiments, the applied current density can be 2 mA / cm², which is suitable for fine synthesis scenarios at lower current densities.

[0046] In some embodiments, the molar ratio of CoO to Co3O4 in the CoO-Co3O4 heterostructure catalyst can be (1-10):(1-10). By adjusting this ratio, the density and electronic structure of the heterostructure can be optimized, thereby further controlling the selectivity of the catalyst for the alcohol oxidation reaction pathway.

[0047] In some embodiments, the flow rate of the pure alcohol solution can be 1-20 mL / min, and the flow rate of the aqueous acidic electrolyte can be 1-50 mL / min. Appropriate flow rate control is beneficial for maintaining stable reactant concentrations, timely removal of products, and improving mass transfer.

[0048] Example 2: This invention provides an asymmetric PEM electrolysis system. As a verification example, benzyl alcohol (BA) is used as the substrate and benzaldehyde (BAD) is used as the target product. The system is tested using an asymmetric PEM electrolysis cell architecture at a working current density of 200 mA / cm².

[0049] The system configuration is as follows: the anode is a carbon felt supported on a CoO-Co3O4 catalyst, and the anode chamber is filled with a pure benzyl alcohol solution; the cathode is isolated from the anode chamber by a perfluorosulfonic acid membrane (Nafion), and the cathode chamber uses an aqueous acidic electrolyte. Under this configuration, electrolysis is performed by applying a current density of 200 mA / cm².

[0050] Test results show that under an industrial-grade load of 200 mA / cm², the selectivity of benzaldehyde remains above 95%; the Faraday efficiency (FE) reaches over 90%; and the electrolysis voltage is reduced by approximately 300-500 mV compared to traditional water electrolysis. These results demonstrate that the system of this invention can operate stably at high current densities while maintaining ultra-high selectivity for aldehyde products, thus solving the pain points of complex product distribution and easy over-oxidation in industrial applications of alcohol oxidation to hydrogen production.

[0051] Comparative Example 1: A conventional alkaline electrolysis system (1M KOH) was used, employing the same CoO-Co3O4 catalyst. The test results showed that the selectivity for benzaldehyde was less than 10%.

[0052] Failure analysis shows that under alkaline conditions, the generated benzaldehyde rapidly undergoes a disproportionation reaction to transform into benzoate, and under high current, it is extremely prone to excessive oxidation with 4 electrons to generate acid.

[0053] Comparative Example 2: A standard symmetrical PEM electrolysis system with no interface control (aqueous acidic PEM electrolyzer) was used, with commercially available Co3O4 as the anode catalyst. Test results showed that the selectivity for benzaldehyde was approximately 35%.

[0054] Failure analysis showed that the lack of a CoO / Co3O4 heterointerface to accelerate the PCET step resulted in sluggish reaction kinetics, significant oxygen evolution reaction at the anode, significantly reduced Faraday efficiency and interfered with the selectivity of alcohol oxidation.

[0055] Comparative Example 3: A commercially available noble metal Pd / C catalyst was used in an asymmetric PEM system. The test results showed that the selectivity for benzaldehyde was approximately 45%, accompanied by significant benzoic acid formation.

[0056] Failure analysis shows that although Pd catalysts have high activity, it is difficult to precisely control the number of electron transfer steps. Under high current density, they are more prone to deep dehydrogenation and over-oxidation, and are difficult to stabilize in aldehyde intermediates.

[0057] Table 1. Comparison of core test data (at 200mA / cm²)

[0058] Referring to Table 1, and combining the above-mentioned Example 2 and Comparative Examples 1-3, the core test data are compared as follows: At 200 mA / cm², Example 2 (CoO-Co3O4 / asymmetric PEM) of this application has a benzaldehyde selectivity >95%, a Faraday efficiency >90%, and an energy saving effect (ΔV vs CWE) of approximately 400 mV; Comparative Example 1 (CoO-Co3O4 / alkaline water system) has a benzaldehyde selectivity <10%, a Faraday efficiency of approximately 85% (total), and an energy saving effect of approximately 300 mV; Comparative Example 2 (Co3O4 / symmetric PEM) has a benzaldehyde selectivity of 35%, a Faraday efficiency <60%, and an energy saving effect of approximately 150 mV; Comparative Example 3 (Pd / C / asymmetric PEM) has a benzaldehyde selectivity of 45%, a Faraday efficiency of 75%, and an energy saving effect of approximately 350 mV.

[0059] This invention successfully overcomes the inherent trade-off between activity and selectivity through dual regulation of interface energy barrier design and asymmetric reaction environment control. The system can support stable operation at a high current density of 200 mA / cm² while maintaining >95% aldehyde selectivity, solving the pain points of complex product distribution and easy over-oxidation in industrial applications of alcohol oxidation to hydrogen production.

[0060] This invention employs an asymmetric architecture design, physically isolating the pure alcohol solution (anolyte) from the aqueous electrolyte (cathode solution). This effectively suppresses excessive oxidation caused by water molecules and prevents the dissolution of the metal catalyst in an acidic environment. Secondly, through CoO-Co3O4 interfacial catalysis, using a cobalt oxide / cobalt tetroxide heterojunction catalyst, the electronic structure modulation at the interface significantly reduces the energy barrier of the first proton-coupled electron transfer (PCET) step, which is the rate-determining step in the oxidation of alcohol to aldehyde. Finally, through optimization of the acidic medium, it was determined that an acidic medium is the optimal chemical environment to prevent the Cannizzaro disproportionation reaction and excessive oxidation of aldehydes, thus ensuring high selectivity of aldehyde products at the source.

[0061] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the above embodiments should be considered exemplary rather than restrictive in all respects; the scope of protection of the present invention is defined by the appended claims, not by the foregoing description, and thus all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0062] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity; those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention fall within the scope of protection of the claims of this invention.

Claims

1. An asymmetric PEM electrolysis system, characterized in that, include: The anode chamber is used to contain a pure alcohol solution; The cathode chamber is used to contain an aqueous acidic electrolyte. A proton exchange membrane is disposed between the anode chamber and the cathode chamber to isolate the pure alcohol solution from the aqueous acidic electrolyte and to conduct protons, thereby forming an asymmetric reaction environment. An anode catalyst is disposed in the anode chamber, and the anode catalyst is a catalyst having a CoO-Co3O4 heterostructure.

2. The asymmetric PEM electrolysis system according to claim 1, characterized in that, The catalyst with a CoO-Co3O4 heterostructure is supported on a carbon felt.

3. The asymmetric PEM electrolysis system according to claim 1, characterized in that, The proton exchange membrane is a perfluorosulfonic acid membrane.

4. The asymmetric PEM electrolysis system according to claim 1, characterized in that, The cathode chamber is equipped with a cathode catalyst, which is platinum-carbon, platinum black, or a transition metal hydrogen evolution catalyst.

5. A method for PEM electrolysis based on asymmetry, characterized in that, The asymmetric PEM electrolysis system according to any one of claims 1-4 includes the following steps: A pure alcohol solution is introduced into the anode chamber, and an aqueous acidic electrolyte is introduced into the cathode chamber. When an electric current is applied, the pure alcohol solution in the anode chamber undergoes a partial oxidation reaction under the action of the CoO-Co3O4 heterogeneous interface catalyst to generate aldehyde products. At the same time, protons are released, which migrate through the proton exchange membrane to the cathode chamber and are reduced to generate hydrogen gas on the cathode surface, thus completing the PEM electrolysis.

6. The asymmetric PEM electrolysis method according to claim 5, characterized in that, The pure alcohol solution is a benzyl alcohol solution, and the aldehyde product is benzaldehyde.

7. The asymmetric PEM electrolysis method according to claim 5, characterized in that, The density of the applied current is 100-500 mA / cm², and the temperature of the applied current is 20-80℃.

8. The asymmetric PEM electrolysis method according to claim 7, characterized in that, The density of the applied current is 2 mA / cm².

9. The asymmetric PEM electrolysis method according to claim 5, characterized in that, In the CoO-Co3O4 heterostructure catalyst, the molar ratio of CoO to Co3O4 is (1-10):(1-10).

10. The asymmetric PEM electrolysis method according to claim 5, characterized in that, The flow rate of the pure alcohol solution is 1-20 mL / min, and the flow rate of the aqueous acidic electrolyte is 1-50 mL / min.

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