What question did this study set out to answer?

The aim is to create efficient catalysts for seawater electrolysis by utilizing single-atom ruthenium sites.

February 26, 20260 citations

Single-Atom Ruthenium Sites on Cobalt-Titanium Surfaces for Efficient and Selective Chloride Electrolysis.

NYNael G. YasriUniversity of Calgary PKPawan KumarUniversity of Calgary MKMd Golam KibriaUniversity of Calgary

Key Points

The aim is to create efficient catalysts for seawater electrolysis by utilizing single-atom ruthenium sites.
Incorporated isolated ruthenium single-atom sites on Co2TiO4/Ti supports
Used Ru-EDTA complexes via electrostatic approach
Analyzed electrochemical performance including overpotential and Tafel slope
Conducted structural characterization with X-ray absorption spectroscopy
Achieved an overpotential of 26.2 mV at 10 mA cm-2
Recorded a Tafel slope of 39.2 mV dec-1
Demonstrated 87% selectivity toward active chlorine in sodium chloride solutions
Showed improved atomic utilization and durability compared to previous catalysts

Abstract

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.

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