A one-step, facile supercritical-ethanol-fluid synthesis of Se-modified Ru nanoparticles nucleated on carbon defects is reported, and it is demonstrated that these nanoparticles provide, with >70% efficiency at 1 A g−1, a highly active and reversible oxygen-reduction/oxygen-evolution reaction on an air cathode in a nonaqueous electrolyte. The Se modification not only prevents Ru oxidation during charge/discharge cycling, but also improves the catalytic activity by promoting Li2O2 versus Li2O deposited on the Ru particles during discharge. A computational calculation with density functional theory supports the role of a larger electron transfer to the oxygen of Li2O2 adsorbed on a surface layer of RuSe2−δ than on a surface layer of RuO2, thereby shifting the more stable adsorbent from Li2O to Li2O2.
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- Li-O batteries
- oxygen evolution reaction
- oxygen reduction reaction
- ruthenium selenide