Toward Deoxygenation Electrolyze with Compensating Catechol Oxidation

One of the major challenges with aqueous‐based thermal fluids is the corrosion of metal components such as pipes, heat exchangers, and boilers, mainly caused by dissolved oxygen (DO) in water. To mitigate this, industrial systems commonly apply water deoxygenation strategies to reduce corrosion, extend equipment lifespan, and lower maintenance costs. In this work, a novel electrochemical deoxygenation approach is presented that leverages a sacrificial redox additive to enhance performance and sustainability. Specifically, catechol, a low‐cost, nontoxic compound derived from lignin, is added to the thermal fluid to act as a sacrificial reactant. Its oxidation replaces the overoxidation of the carbon anode, thereby protecting the electrode and simultaneously driving the oxygen reduction reaction at the cathode. When a low voltage (1 V) is applied across two porous flow‐through carbon electrodes in a fluid containing 0.1 M NaCl and catechol, the DO concentration drops from 8.8 to 0.2 mg L −1 (with 0.001 M catechol) or even 0.06 mg L −1 (with 1 M catechol), at an energy cost of only 0.263 Wh L −1 . This strategy significantly reduces energy consumption compared to traditional vacuum degassing, while using sustainable materials compatible with scalable, low‐cost deployment.