Adaptability of ruthenium iridium titanium anodes in sodium hypochlorite electrolysis

After direct current is applied to the electrolytic cell, various ions in the electrolyte migrate directionally under the action of the electric field. Independent reaction zones are formed at the anode and cathode, where different oxidation-reduction reactions occur. The anode is responsible for the core chlorine evolution reaction through chloride ion oxidation. NAVI Titanium focuses on anode configurations suited to this reaction environment. Chloride ions lose electrons to generate chlorine gas, which then undergoes disproportionation with water to form hypochlorous acid, ultimately dissociating into sodium hypochlorite. At the cathode, only the auxiliary side reaction of water reduction and hydrogen evolution occurs. Since the operating conditions are relatively mild with no severe corrosion risk, the material selection requirements for the two electrodes are significantly different. The anode must be manufactured from specially designed corrosion-resistant catalytic materials.

The brine used in sodium hypochlorite electrolysis contains a large amount of free chloride ions, which have strong pitting corrosion and crevice corrosion capabilities. Conventional iron materials, copper materials, and ordinary stainless steels rapidly undergo electrochemical corrosion under energized high-salt conditions, resulting in rusting, perforation, and substrate detachment. These issues not only cause electrode failure but may also contaminate the disinfected water. Therefore, NAVI Titanium dedicated anodes must possess excellent resistance to chloride ion electrochemical corrosion and be capable of long-term exposure to high-salt media erosion and attack.

The anode is the core catalytic carrier in sodium hypochlorite electrolysis. The production efficiency, energy consumption, and operational stability of the equipment depend entirely on the electrochemical performance of the ruthenium iridium titanium anode. High-quality anodes can selectively catalyze the main chlorine evolution reaction of chloride ions while minimizing ineffective side reactions such as oxygen evolution from water electrolysis. NAVI Titanium anodes maintain stable catalytic activity without degradation under long-term energized polarization conditions, ensuring high current utilization efficiency and uniform, stable sodium hypochlorite concentration.

Pure titanium substrates have no inherent electrochemical catalytic activity. However, due to their excellent chemical stability, they can rapidly form a dense and stable titanium dioxide passivation film in high-salt, strongly oxidizing electrolytes. This completely isolates the substrate from corrosive media and electrochemical penetration, providing a strong, smooth, and durable supporting foundation for the surface ruthenium-iridium active coating. NAVI Titanium applies this substrate principle to ensure strong adhesion of the high-temperature sintered coating and prevent coating detachment, serving as the fundamental basis for the stable catalytic performance of the ruthenium iridium titanium anode.

Ruthenium iridium titanium anodes provide four major unique advantages: First, they offer high chlorine evolution catalytic efficiency and low energy consumption. The specialized coating has an extremely low chlorine evolution overpotential, with current efficiency reaching above 85%. Under the same operating conditions, chlorine production is more stable and energy consumption is lower. Second, they demonstrate excellent anti-passivation and corrosion resistance. They can withstand high-chlorine, strongly oxidizing environments and continuous polarization stress for long periods, with no significant reduction in surface activity. Third, they provide strong coating adhesion and long service life. NAVI Titanium high-temperature sintered coating bonds firmly with the titanium substrate, resisting powdering and peeling. The stable service life can reach 3–8 years. Fourth, they provide excellent reaction selectivity and stable water quality. They effectively suppress unwanted side reactions, improve raw material utilization efficiency, and ensure pure sodium hypochlorite solution with stable concentration, meeting various water disinfection standards.