Inorganic-Electrochemistry Seminar

Rare earth elements are essential in renewable energies technologies including in permanent magnets for wind turbines, hybrid and electric vehicles, energy efficient lighting phosphors and many others. In 2010 the price of dysprosium skyrocketed to nine times that of gold. Since then, the price of dysprosium and the other rare earth elements has collapsed. But the picture of a global market dominated by suppliers in the PRC has not fundamentally changed. The separations chemistry at the heart of obtaining pure rare earth materials still relies on inefficient liquid-liquid extraction. We have identified hydroxylamines as superior ligands for exploring new directions in rare earths separations chemistry. In particular, a tripodal ligand, H₃TriNOx, was developed and its coordination chemistry established. The RE(TriNOx) RE = La–Lu, Y series led to identification of an unusual solubility dependence of the resulting complexes. These observations have afforded a new method for separating RE elements, in particular, for their recycling from consumer materials. In a related project, we have been working to develop the coordination chemistry and organometallic chemistry of cerium and to understand the physicochemical characteristics that underlie the stability of complexes in the cerium(IV) oxidation state. We have shown that light provides another probe to interrogate Ce(III/IV) redox cycling, which can be directed into new stoichiometric and catalytic photoredox chemistry on organic substrates. The results of these studies and their implications for new one-electron chemistry with cerium will be presented.