The development of efficient, stable, cost-effective catalysts for seawater electrolysis is crucial to achieving carbon neutrality and sustainability. Isolated ruthenium single-atom sites in Ru-O coordination environments are incorporated onto Co2TiO4/Ti supports via an electrostatic approach using Ru-ethylenediaminetetraacetic acid (EDTA) complexes, enabling atomic-Ru dispersion through interactions between Ru(EDTA)- and metal hydroxide precursors. The resulting Ru(SA)-Co2TiO4/Ti catalyst, with an ultra-low Ru loading of 0.08 mg cm- 2 (- 2, a Tafel slope of 39.2 mV dec- 1, and 87% selectivity toward active chlorine in seawater-relevant sodium chloride solutions, outperforming state-of-the-art CER systems while using less Ru. Compared to Ru(NC)-Co2TiO4/Ti-prepared by direct RuCl3 deposition without chelating agents and featuring RuO2 nanoclusters (NC)-the single-site structure in Ru(SA)-Co2TiO4/Ti shows significantly improved atomic utilization and durability. Electrochemical analysis indicates that both catalysts share a rate-determining second electron transfer step, yet Ru(SA)-Co2TiO4/Ti exhibits proton-independent CER kinetics across pH 4.5-9. Structural characterization and X-ray absorption spectroscopy (XANES and EXAFS) confirm the presence of oxygen-coordinated, mixed-valence Ru3+/Ru4+ single-atom Ru within the orthorhombic Co2TiO4 phase, accompanied by increased Coδ+ and oxygen vacancies, promoting Cl- adsorption and facilitating Cl2 formation via a positive-valent chlorine intermediate.
Yasri et al. (Mon,) studied this question.