Electrode for enhancing mass transfer, and use of electrode
By optimizing the electrode structure to a porous electrode composed of rhombic nickel mesh, nickel foam, and nickel wire mesh, the problem of limited mass transfer in the electrolysis system was solved, improving electrolysis efficiency and energy utilization, reducing energy consumption, and realizing a highly efficient organic oxidation and hydrogen production process.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- QUZHOU INSTITUTE FOR INNOVATION IN RESOURCE CHEMICAL ENGINEERING
- Filing Date
- 2025-01-10
- Publication Date
- 2026-06-18
Smart Images
Figure CN2025071660_18062026_PF_FP_ABST
Abstract
Description
An electrode for enhancing mass transfer and its application Technical Field
[0001] This invention belongs to the field of electrocatalytic conversion, specifically relating to an electrode that enhances mass transfer and its application. Background Technology
[0002] In electrochemical reactions, the substrate needs to be transferred from the bulk electrolyte to the electrode surface. Then, the substrate adsorbs onto the electrode while electron transfer converts the reactants into products. Finally, the products desorb from the electrode and diffuse back into the bulk electrolyte. The electrolysis process includes mass transfer and charge transfer at the electrode interface. As the polarization potential increases, the reactants are immediately converted upon reaching the electrode surface, and the reactant concentration at the electrode surface approaches zero. Mass transfer then becomes the rate-determining step. Therefore, enhancing the mass transfer process is an effective method to increase the electrolysis reaction rate.
[0003] Most organic electro-oxidation processes are liquid-phase dilute substance conversion processes, and current research largely focuses on catalyst development, which exhibits good catalytic effects; however, existing electrolysis systems face significant challenges in industrial applications. In catalyst development research, catalyst evaluation is generally conducted in batch reactors. Batch reactors typically use external forced stirring to rapidly bring reactants from the bulk electrolyte to the electrode surface, enhancing mass transfer and mitigating, to some extent, the problem of low reactivity caused by limited mass transfer. In contrast, in flow electrochemical reactors, the electrolyte flow tends to be laminar, with almost no radial flow, weak convective mass transfer, reduced electrochemical reaction rates, and the generation of side reactions.
[0004] Optimizing electrode structure can improve the mass transfer of reactants on the electrode surface, thereby increasing reaction rate and energy efficiency. Several key factors influencing the mass transfer process include specific surface area, pore structure, and stability. Specifically, the specific surface area of the electrode determines the effective surface area for contact between the electrode and the reactants; a larger specific surface area results in a larger contact area between the substrate and the electrode, leading to improved mass transfer efficiency. The pore structure of the electrode affects the diffusion and adsorption of the substrate on the electrode surface. A suitable pore structure can provide more active sites and promote mass transfer of reactants, thus improving reaction efficiency. Existing research has focused on improving electrochemical reaction efficiency through electrode structure. For example, Smith CZ et al. modified a commercial pressure-filtration flow reaction system using porous nickel sheets with a high specific surface area as the electrode material. The pore structure of the 3D nickel sheet provides more channels, allowing the electrolyte to contact the electrode more fully, thereby promoting the mass transfer process and reaction efficiency. Anodic degradation of lignin was conducted in the modified flow reactor. The results showed that the degradation yield in this reactor was comparable to that of industrial processes, indicating that the porous nickel anode effectively enhanced mass transfer between lignin and the electrode. Therefore, developing a suitable electrode structure that matches the reactor structure and the reaction can effectively improve mass transfer efficiency and energy efficiency. Summary of the Invention
[0005] This invention aims to reduce the energy consumption of existing water electrolysis hydrogen production coupled with organic oxidation technology, and its purpose is to provide an electrode that enhances mass transfer and its application.
[0006] This invention is achieved through the following technical solution:
[0007] An electrode for enhancing mass transfer includes a diamond-shaped nickel mesh layer, a nickel foam layer, and a nickel wire mesh layer arranged sequentially; the nickel foam layer is made of flattened nickel foam; and the nickel wire mesh layer is made of nickel wire mesh.
[0008] In the above technical solution, the foamed nickel layer and the nickel wire mesh layer are pressed together by a hot press, and the diamond-shaped nickel mesh layer is placed on top of the foamed nickel layer, with no fixing agent between them.
[0009] In the above technical solution, the sum of the thicknesses of the foamed nickel layer and the nickel wire mesh layer is 0.3mm to 1.5mm.
[0010] In the above technical solution, the sum of the thicknesses of the rhombic nickel mesh layer, the foamed nickel layer, and the nickel wire mesh layer is 0.5mm to 3mm, which can be changed according to the reaction and reactor configuration.
[0011] In the above technical solution, the thickness of the rhombic nickel mesh layer is 0.2mm to 2mm; the aperture of the large-hole rhombic nickel mesh is at the millimeter level.
[0012] In the above technical solution, the thickness of the nickel foam layer is 0.5mm to 5mm; the pore size of the nickel foam is 30ppi to 110ppi.
[0013] In the above technical solution, the thickness of the nickel wire mesh layer is 0.02mm to 0.2mm; the aperture of the nickel wire mesh is 100 mesh to 800 mesh.
[0014] Application of the aforementioned mass transfer enhanced electrode in a reactor containing an ion exchange membrane, wherein the mass transfer enhanced electrode is positioned between the membrane electrode and the anode end plate.
[0015] In the above technical solution, the nickel wire mesh layer is in contact with the integrated film electrode, and the diamond-shaped nickel mesh layer is in contact with the end plate.
[0016] In the above technical solution, the reactor containing the ion exchange membrane includes a modular flow reactor for electrocatalytic hydrogen production coupled with biomass molecular oxidation and a device for electrosynthesizing high-concentration 2,5-furandicarboxylic acid coupled with hydrogen production.
[0017] The beneficial effects of this invention are:
[0018] This invention provides an electrode for enhanced mass transfer and its application. By optimizing the electrode structure, it improves the mass transfer of reactants on the electrode surface, thereby increasing the reaction rate and energy efficiency. When applied to a reactor, the porous structure of the electrode increases the radial flow velocity of the electrolyte, effectively promoting convection and enhancing mass transfer during the electrolysis of dilute substances in the liquid phase. This, in turn, improves electrolysis efficiency, substrate conversion, product yield, and Faraday efficiency. The electrode of this invention is applied to a large-scale water electrolysis hydrogen production coupled with oxidation process, achieving stable operation of organic oxidation at high current densities and reducing energy consumption in the process. Attached Figure Description
[0019] Figure 1 is a schematic diagram of the structure of the electrode for enhancing mass transfer according to the present invention;
[0020] Figure 2 is a physical diagram of the electrode for enhanced mass transfer according to the present invention;
[0021] Figure 3 is a CT three-dimensional reconstruction of the electrode that enhances mass transfer in Comparative Example 1 of the present invention;
[0022] Figure 4 is a Faraday efficiency distribution diagram of each product in the electro-oxidation of 5-hydroxymethylfurfural in Example 2 of the present invention;
[0023] Figure 5 is a distribution of the Faraday efficiency of each product in the electro-oxidation of 5-hydroxymethylfurfural in Comparative Example 1 of the present invention.
[0024] Figure 6 is a comparison diagram of the streamline trajectories of the fluid in the electrode with enhanced mass transfer in Embodiment 1 and Comparative Example 1 of the present invention.
[0025] The structure consists of: 1. a diamond-shaped nickel mesh layer; 2. a foamed nickel layer; and 3. a nickel wire mesh layer.
[0026] For those skilled in the art, other related figures can be obtained from the above figures without any creative effort. Detailed Implementation
[0027] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0028] Example 1
[0029] As shown in Figures 1 and 2, an electrode for enhancing mass transfer includes a rhomboid nickel mesh layer 1, a foamed nickel layer 2, and a nickel wire mesh layer 3 arranged sequentially.
[0030] The diamond-shaped nickel mesh layer 1, the foamed nickel layer 2, and the nickel wire mesh layer 3 are flattened by a hot press.
[0031] The rhombic nickel mesh layer 1 adopts a large-aperture rhombic nickel mesh with dimensions of 8.0cm × 12.5cm and a thickness of 0.4mm; the aperture of the large-aperture rhombic nickel mesh is 2mm × 4mm.
[0032] The nickel foam layer 2 is made of flattened nickel foam, with dimensions of 8.0cm × 12.5cm and a thickness of 1.7mm; the pore size of the nickel foam is 100ppi; the thickness of the flattened nickel foam is determined according to requirements.
[0033] The nickel wire mesh layer 3 has dimensions of 8.0cm × 12.5cm and a thickness of 0.035mm; the mesh size is 300 mesh.
[0034] The mass transfer-enhancing electrode described in Example 1 can be applied to the modular flow reactor for electrocatalytic hydrogen production coupled with biomass molecular oxidation disclosed in patent ZL 2023 2 3420373.8, and can also be applied to the device for electrosynthesis of high-concentration 2,5-furandicarboxylic acid coupled with hydrogen production disclosed in patent ZL2023 2 0352381.4.
[0035] Example 2
[0036] A modular flow reactor for electrocatalytic hydrogen production coupled with biomass molecular oxidation is disclosed. It includes the mass transfer-enhancing electrode of Example 1. The structure of the modular flow reactor for electrocatalytic hydrogen production coupled with biomass molecular oxidation is the same as that in patent ZL 2023 2 3420373.8. In the reactor, the mass transfer-enhancing electrode is placed between an integrated membrane electrode and the anode end plate. The nickel wire mesh layer 3 is in contact with the integrated membrane electrode, and the rhombic nickel mesh layer 1 is in contact with the anode end plate. Electrolysis is performed at the anode using 1.5M potassium hydroxide and 300mM 5-hydroxymethylfurfural as the electrolyte, with a single-pass feed method.
[0037] As shown in Figure 4, at 0.1A cm -2 The current density yielded ~100% Faradaic efficiency for the target product (2,5-furandicarboxylic acid), 0.2–1 A cm⁻¹. -2 The target product (2,5-furandicarboxylic acid) still maintains a Faradaic efficiency of >85% at high current densities. The lack of significant improvement in Faradaic efficiency at high current densities is limited by the substrate concentration. If the reactant concentration is further increased (e.g., 800 mM 5-hydroxymethylfurfural), the Faradaic efficiency of the target product (FDCA) can also reach over 90%.
[0038] Comparative Example 1
[0039] A modular flow reactor for electrocatalytic hydrogen production coupled with biomass molecular oxidation is disclosed, comprising an electrode for enhanced mass transfer. The structure of the modular flow reactor for electrocatalytic hydrogen production coupled with biomass molecular oxidation is the same as that in patent ZL 2023 2 3420373.8. The electrode for enhanced mass transfer adopts a double-layer structure composed of a nickel foam layer 2 and a nickel wire mesh layer 3, and its CT three-dimensional reconstruction image is shown in Figure 3. The relevant parameters of the nickel foam layer 2 and the nickel wire mesh layer 3 are the same as those in Example 1. In this comparative example, the nickel wire mesh layer 3 and the nickel foam layer 2 are flattened by a hot press to ensure a thickness of 0.4 mm.
[0040] In the reactor, the mass transfer enhanced electrode is placed between the integrated membrane electrode and the anode end plate; the nickel wire mesh layer 3 is in contact with the integrated membrane electrode, and the foamed nickel layer 2 is in contact with the anode end plate; the anode is electrolyzed using 1.5M potassium hydroxide and 300mM 5-hydroxymethylfurfural as electrolyte, and the electrolyte is fed in a single-pass manner.
[0041] As shown in Figure 5, at 0.1A cm -2 ~1A cm -2 A Faradaic efficiency of 80–90% was obtained for the target product (2,5-furandicarboxylic acid) within the specified current density range, with the highest partial current density for the electrolysis of 2,5-furandicarboxylic acid reaching 0.8 A cm⁻¹. -2 .
[0042] A comprehensive comparison of the experimental results in Figures 4 and 5 shows that the electrode structure of Comparative Example 1 achieves a higher Faraday efficiency for the target product, indicating that the porous electrode structure enhances the mass transfer process in the electrolysis of dilute liquid substances and improves energy efficiency. The electrode structure of Example 1, by further adding a large-pore rhombic nickel mesh, can further improve the Faraday efficiency, indicating that the mass transfer process is further promoted and the large-pore rhombic nickel mesh effectively promotes the convection of the electrolyte.
[0043] As shown in Figure 6, two electrode structures, Example 1 and Comparative Example 1, were modeled based on CT slice images. Then, fluid simulation was performed using COMSOL software, with the cavity without porous electrode structure serving as a control. The results show that in the cavity without porous electrode structure, the fluid exhibits a completely laminar flow with no radial flow. In the electrode structure containing Comparative Example 1, the fluid exhibits radial flow. In the electrode structure of Example 1, the radial flow of the fluid is more pronounced, and the fluid exhibits a strong turbulent state, further demonstrating that the electrode structure prepared in this invention has a significant enhanced mass transfer effect.
[0044] The principle of this invention:
[0045] The core of this invention is that the large-pore rhombic nickel mesh in the electrode effectively promotes electrolyte convection and enhances the transfer of substrate from the bulk phase to the catalyst surface. The nickel foam in the electrode serves to load the catalyst and promote uniform substrate dispersion. The nickel wire mesh in the electrode supports and loads the catalyst while preventing the nickel foam from puncturing the ion exchange membrane. The entire electrode achieves enhanced mass transfer, improves substrate conversion, increases product yield and Faraday efficiency, and reduces energy consumption in the electrolytic hydrogen production coupled with oxidation, facilitating the realization of low-energy, high-current electrolysis. This electrode structure is simple to prepare, easily scaled up without performance loss, and is conducive to large-scale electrocatalytic organic oxidation coupled with hydrogen production.
[0046] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.
[0047] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model 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, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," etc., 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 with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.
[0048] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0049] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.
Claims
1. An electrode for enhancing mass transfer, characterized in that: It includes a diamond-shaped nickel mesh layer (1), a foamed nickel layer (2), and a nickel wire mesh layer (3) arranged in sequence; the foamed nickel layer (2) is made of flattened foamed nickel; the nickel wire mesh layer (3) is made of nickel wire mesh.
2. The electrode for enhanced mass transfer according to claim 1, characterized in that: The foamed nickel layer (2) and the nickel wire mesh layer (3) are pressed together by a hot press, with the diamond-shaped nickel mesh layer (1) placed on top of the foamed nickel layer (2), and there is no fixing agent between them.
3. The electrode for enhanced mass transfer according to claim 1, characterized in that: The sum of the thicknesses of the foamed nickel layer (2) and the nickel wire mesh layer (3) is 0.3 mm to 1.5 mm.
4. The electrode for enhanced mass transfer according to claim 1, characterized in that: The sum of the thicknesses of the rhomboid nickel mesh layer (1), the foamed nickel layer (2), and the nickel wire mesh layer (3) is 0.5 mm to 3 mm, which can be changed according to the reaction and reactor configuration.
5. The electrode for enhanced mass transfer according to claim 1, characterized in that: The thickness of the rhombic nickel mesh layer (1) is 0.2 mm to 2 mm; the aperture of the large-hole rhombic nickel mesh is in the millimeter range.
6. The electrode for enhanced mass transfer according to claim 1, characterized in that: The thickness of the nickel foam layer (2) is 0.5 mm to 5 mm; the pore size of the nickel foam is 30 ppi to 110 ppi.
7. The electrode for enhanced mass transfer according to claim 1, characterized in that: The thickness of the nickel wire mesh layer (3) is 0.02 mm to 0.2 mm; the aperture of the nickel wire mesh is 100 mesh to 800 mesh.
8. The application of the mass transfer enhanced electrode according to any one of claims 1 to 7 in a reactor containing an ion exchange membrane, characterized in that: The mass transfer enhancement electrode is positioned between the membrane electrode and the anode plate.
9. The application of the mass transfer enhanced electrode according to claim 8 in a reactor containing an ion exchange membrane, characterized in that: The nickel wire mesh layer (3) is in contact with the membrane electrode, and the rhombic nickel mesh layer (1) is in contact with the anode end plate.
10. The application of the mass transfer enhanced electrode according to claim 8 in a reactor containing an ion exchange membrane, characterized in that: The reactor containing an ion exchange membrane includes a modular flow reactor for electrocatalytic hydrogen production coupled with biomass molecular oxidation.