(Invited) Magnetoelectrocatalysis of Oxygen Reduction Reaction (ORR) By Lanthanide Triflates in Acetonitrile

Lanthanides have sufficiently similar chemical and physical properties that lanthanides are difficult to separate. Among the common properties are standard potentials that fall within 100 mV for Ln 3|0 . The standard potentials are sufficiently extreme that lanthanide electrochemistry is commonly undertaken in ionic liquids and molten salts. Recently, it was demonstrated that cyclic voltammetry of lanthanide triflates is accessible in acetonitrile at Nafion modified electrodes. Because at least four different oxidation states of the lanthanides are accessible, the voltammetric response is complex, as demonstrated by fitting the mechanism. Interest in benchtop electrochemistry of lanthanides arose from investigations of magnetoelectrocatalysis, where magnetic properties and spin impact rates of electron transfer at electrodes and electrocatalysts. Despite largely similar properties, lanthanide magnetic properties are diverse because the number of unpaired electrons in the d orbitals ranges from 0 to 7. The presence of lanthanides at the electrode surface mediates rates of important reactions that include the oxygen reduction reaction (ORR). Ytterbium triflate extracted into Nafion on electrode in acetonitrile increase oxygen reduction currents by 15%. On introduction of electrochemically inert hematite microparticles into Nafion, oxygen reduction currents are enhanced 35%. Other measures of catalysis that include decreased overpotential are also observed. Reference Johna Leddy and Krysti L. Knoche, Lanthanide Electrochemistry , published 12 November 2015 as US Patent Application, 20150322581-A1