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As the hydrogen industry accelerates its development, hydrogen production through seawater electrolysis has become an important approach to generating green hydrogen, as it overcomes the limitations associated with freshwater resources. Tantalum, as a key component, and the Ir/Ta mesh formed together with iridium make it an ideal material for the anodes of flow electrolyzers used in seawater electrolysis. The unique physical and chemical properties of tantalum endow tantalum-iridium meshes with excellent electrochemical performance, corrosion resistance, and structural stability, making them key to overcoming the core technical challenges in seawater electrolysis. Their advantages and importance as electrode materials are irreplaceable. The inherent properties of tantalum form the basis for the core performance characteristics of tantalum-iridium meshes. Tantalum’s high corrosion resistance, high melting point, good electrochemical inertness, and excellent compatibility with metals are the reasons why it can serve as a key component in high-end electrodes for seawater electrolysis; these same properties constitute the foundation upon which tantalum-iridium meshes outperform other electrode materials. 1. Exceptional corrosion resistance, suitable for the highly complex electrolyte environment of seawater. Seawater is rich in various inorganic salts such as NaCl and MgCl₂; it has a high concentration of chloride ions and a complex electrolyte system, which imposes strict requirements on the corrosion resistance of electrode materials. Tantalum possesses extremely high chemical stability; it is not easily corroded in neutral, acidic, or even slightly alkaline environments, nor does it react with the ions in seawater, allowing it to effectively resist long-term erosion by seawater. This property enables tantalum-iridium meshes to show no signs of metal discoloration, structural damage, or corrosion on their surface during long-term tests of artificial seawater electrolysis (1 hour of constant current operation) (Figure 1), thereby completely solving the problem of ordinary electrodes failing easily and having a short lifespan in seawater. Fig. 1. Ir/Ta mesh structure after 1 hour of long-term testing. 2. Excellent electrochemical inertness, preventing side reactions from interfering with the electrolysis process. The key to seawater electrolysis is to achieve high selectivity for the oxygen evolution reaction (OER) and to reduce side reactions such as the chlorine evolution reaction (CER). Tantalum itself possesses excellent electrochemical inertness; within the potential range of seawater electrolysis, it does not participate in redox reactions nor catalyze the oxidation of chloride ions. It serves merely as a high-quality substrate to support the OER catalytic activity of iridium, thereby significantly reducing the occurrence of unwanted side reactions and laying the foundation for efficient OER catalysis using tantalum-iridium meshes. 3. Good metal bonding and structural stability ensure long-term performance of the electrodes. Tantalum possesses strong metal bonding capabilities, allowing it to form a uniform and dense alloy network structure with iridium; this enables the catalytic active sites of iridium to remain firmly attached to the tantalum-based framework, preventing the loss or detachment of these catalytic components during the electrolysis process. At the same time, tantalum has a melting point of up to 2996°C and excellent thermal stability; even if local temperature increases occur during the electrolysis process, it does not cause deformation of the electrode structure. This allows the tantalum-iridium mesh to maintain its stable mesh shape, ensuring smooth flow of the electrolyte and efficient transfer of electrical charge. As a result, the system resistance of the flow electrolyzer remains at a low level of 2.2 ohms, thereby ensuring the efficiency of the electrolysis process. Tantalum-iridium meshes with tantalum as the core material have become the optimal choice for anodes in seawater electrolysis. By combining the structural advantages of tantalum with the OER catalytic properties of iridium, these meshes serve as the key materials for commercial seawater electrolysis anodes; their performance far exceeds that of other electrodes, making them an indispensable component in the production of hydrogen through seawater electrolysis. This is a direct indication of the importance of tantalum as a material for electrodes in new energy applications. 1. Low overpotential and high catalytic activity: The OER performance is superior to that of similar electrodes. The core goal of seawater electrolysis is to achieve efficient OER, and tantalum-based tantalum-iridium meshes exhibit excellent OER catalytic activity. Experimental data show that the OER overpotential of the tantalum-iridium mesh is only 430 mV, which is significantly lower than that of the tantalum-iridium mesh loaded with manganese oxide (MnOx) (540 mV) and the platinum-titanium mesh cathode (590 mV) (Figure 2). This advantage stems from the inert nature of tantalum, which allows the catalytic active sites of iridium to remain fully exposed without interference from unwanted side reactions; as a result, water can be oxidized and split at lower potentials, thereby significantly reducing the energy consumption required for seawater electrolysis and improving hydrogen production efficiency. Figure 2. Ir/Ta network structure, Ir/Ta + MnOx, and titanium plating mesh—the surface areas determined using the Randles-Sevcik equation were normalized for cyclic voltammetry under experimental conditions of iron/ferricyanide-0.1M potassium hydroxide electrolyte. 2. It has strong structural adaptability; the tantalum-iridium mesh selected for the design and research of flow electrolyzers has a size of 4.5×4.5 cm², which is suitable for flow electrolyzers with an active area of 5×5 cm². The tantalum-based mesh structure features a specific geometric area conversion factor (Table 1), allowing it to fit precisely with the electrolyzer’s EPDM gaskets and ion exchange membranes, thus forming a tight “sandwich” assembly structure (Figure 3). The structural rigidity of tantalum prevents the electrodes from deforming during assembly compression, which ensures tight contact between the electrodes and the membrane while avoiding damage to the membrane. This effectively reduces the contact resistance, allowing the entire electrolysis system to maintain low resistance and high conductivity. Table 1. Dimensional parameters of Ir/Ta screens (identical to Ir/Ta + MnOx) and Pt Ti screens used for calculating geometric area. Universal conversion factor for Ir/Ta screens (the same as Ir/Ta + MnOx). Figure 3. Schematic diagram of the flow electrolyzer assembly. (a) Plastic-based housing panel, equipped with electrolyte inlet and outlet adapters ； (b) EPDM foam layer ； (c) Nafion R○117 membrane ； (d) Covered with a thin layer of EPDM foam on both sides ； (e) Anode and cathode electrodes are placed on either side of the membrane respectively ； (f) Flow electrolyzer interlayer structure ； (g) Copper wires connecting the dual electrodes to the waveform-driven potentiostat ； (h) Assembled flow electrolyzer ； (i) Ir/Ta network structure as the anode electrode ； (j) Pt-Ti mesh as the cathode electrode. 3. Long-term stable operation makes large-scale seawater electrolysis feasible. Large-scale seawater electrolysis for hydrogen production requires extremely high long-term stability of the electrodes, and the stability of tantalum-based tantalum-iridium meshes is outstanding. In long-term tests of artificial seawater electrolysis at a constant current of 0.5 A, the tantalum-iridium mesh showed no corrosion on its surface, and its cell voltage even decreased slightly as the polarization time increased (Figure 4), demonstrating improved stability over time. This performance is attributed to the high corrosion resistance and structural stability of tantalum, which enables it to withstand long-term erosion by seawater as well as the electrical stress associated with electrolysis processes. This addresses the problem of ordinary electrodes deteriorating easily in seawater and requiring frequent replacement, thereby providing a key material foundation for the large-scale and industrial application of seawater electrolysis for hydrogen production. Figure 4. Screenshot of the CP measurement results for the Ir/Ta mesh, with a long-term testing time of 1 hour. The inherent advantages of tantalum enable the modification of tantalum-iridium meshes to be feasible, thus helping to overcome the key challenges in seawater electrolysis. The biggest technical obstacle in seawater electrolysis is the competition between OER and CER processes. Although tantalum-iridium meshes possess excellent OER activity, it is still necessary to further suppress CER through modification. The stable properties of tantalum ensure that such modifications are feasible and yield consistent results, providing a crucial foundation for overcoming this core challenge. This also reflects the importance of tantalum in the development of materials for seawater electrolysis. To suppress CER and enhance OER selectivity, the study employed electrodeposition to deposit a MnOx coating on the surface of the tantalum-iridium mesh. The two advantages of the tantalum-based substrate led to a more effective modification effect: 1. Tantalum possesses high surface stability, which enables it to form a strong bond with the MnOx coating, allowing the deposited MnOx to adhere evenly to the surface of the tantalum-iridium mesh and thus create a dense barrier against the diffusion of chloride ions, effectively preventing their spread to the anodic catalytic sites ； 2. The electrochemical inertness of titanium does not undergo any side reactions with the MnOx coating, ensuring that the function of the MnOx coating is merely to suppress CER, without interfering with the OER catalytic activity of iridium. The modification test results showed that the tantalum-iridium mesh loaded with 20 mC/cm² of MnOx experienced a significant decrease in CER Faradaic efficiency under high current operation of 0.5 A, with stable performance across multiple tests (Figure 5); meanwhile, the cell voltage also dropped from 5.32 V for the original tantalum-iridium mesh to 4.85 V (Table 2). Without the support of a stable tantalum substrate, the MnOx coating tends to peel off and the modification effect diminishes, making it impossible to achieve long-term CER suppression. The successful modification of tantalum-based tantalum-iridium meshes provides an effective solution to the challenge of competition between OER and CER in seawater electrolysis, and the core foundation of this achievement lies in the excellent properties of tantalum. Figure 5. Relationship between chlorofaradic efficiency and different MnOx loadings under operating conditions of 0.5 A current. Table 2. Analysis of average voltage under different loading conditions of MnOx on Ir/Ta mesh structures using the chronopotential method (CP). The irreplaceability of tantalum in the industry of hydrogen production through seawater electrolysis underscores the value of core materials as they move from laboratory research to industrial application. As the core substrate for tantalum-iridium meshes, tantalum offers advantages throughout the entire process of hydrogen production via seawater electrolysis, making it an indispensable core material for the development of this industry. Its importance is evident in three aspects: 1. Material aspect: Tantalum’s corrosion resistance, electrochemical inertness, and structural stability make it one of the best choices among existing metal materials for use in seawater electrolysis environments; no other metal can replace tantalum in terms of overall performance as a substrate for high-end electrolytic electrodes ； 2. In terms of performance: Tantalum provides a stable structure and electrochemical foundation for the tantalum-iridium mesh, enabling the full utilization of iridium’s catalytic activity and thus achieving high efficiency and low energy consumption in OER processes. It also ensures long-term stability of the electrode, which lays the basis for improving the efficiency and reducing the costs of hydrogen production through seawater electrolysis ； 3. At the industrial level: The successful application and modifiability of tantalum-based tantalum-iridium meshes have overcome the key technical challenges in seawater electrolysis, providing essential material support for the large-scale and industrial development of hydrogen production via seawater electrolysis. This helps the hydrogen industry reduce its reliance on freshwater resources and enables sustainable production of green hydrogen. Summary: Tantalum – the key material underlying hydrogen production via seawater electrolysis. Thanks to its exceptional corrosion resistance, excellent electrochemical inertness, good structural stability, and metal-binding properties, tantalum serves as the core component of tantalum-iridium meshes, which in turn gives these meshes their key advantages as anodes for seawater electrolysis. From adapting to the complex electrolyte environment of seawater, to ensuring the high catalytic activity and long-term stability of electrodes, to enabling breakthroughs in electrode modification that address the key challenges in seawater electrolysis, every property of tantalum plays an irreplaceable role in hydrogen production via seawater electrolysis. As the core substrate material for high-end electrodes in seawater electrolysis, tantalum is not only crucial for achieving efficient and selective seawater electrolysis in laboratory research, but also serves as the fundamental material for the large-scale and industrial development of hydrogen production through seawater electrolysis in the future. Its unique advantages and core value in new energy electrode materials will also gain broader recognition and application as the hydrogen energy industry develops. Statement: This article was first published on the WeChat official account; the original title is: 【Tantalum-based core material — The key advantages and core value of tantalum-iridium mesh in seawater electrolysis for hydrogen production】