Enhancing Chlorine Evolution Performance of Ru-Based DSA Electrodes via Cobalt Incorporation for Direct Electrolysis of Seawater

Abstract

Titanium-based metal oxide anodes exhibit strong application potential in chlorine evolution antifouling systems from seawater electrolysis. Conventional dimensionally stable anodes (DSA) rely primarily on Ru- and Ir-based noble metal coatings, yet their large-scale industrial application is hindered by high costs and poor chlorine production efficiency. To overcome the aforementioned shortcomings, Co is introduced into the RuIrTiOx/Ti system, adopting a preparation process involving oxalic acid pretreatment and multi-step coating to fabricate RuIrCoTiOx/Ti electrodes. XRD and TEM results indicate a solid solution coating with uniformly dispersed elements formed on the electrode. The RuIrCoTiOx/Ti electrode demonstrates superior catalytic activity and nearly 84.4% faraday efficiency derived from the chlorine evolution compared to binary or ternary metal oxide-coated counterparts. Remarkably, the electrode maintains over 98.1% of its initial activity after 200 hours of continuous electrolysis. While the slightly reduced durability of RuIrCoTiOx/Ti compared to RuIrTiOx/Ti may be caused by an increased specific surface area of the mixed oxide coating and the formation of higher valence states of Ru species after Co incorporation, as evidenced by SEM and XPS results. This study provides an effective design strategy for developing low-cost, high efficiency DSA electrodes, offering promising prospects for industrial application. Keywords: seawater electrolysis, DSA, Chlorine production efficiency, RuIrCoTiOx/Ti