Physical Chemistry Seminar – Margaret Reece

About the event

Title: Energetics of Pyrochlore Nanoparticles

Abstract: Pyrochlore-based ceramic waste form (A2B2O7) is one of the promising candidates for immobilizing long-lived isotopes. While pyrochlore materials have been heavily investigated in the bulk size for thermodynamic stability and radiation resistance, relatively limited work has been performed at the nanoscale. The main difference is that enthalpy contributions from interfaces and surfaces are negligible in the bulk phase, but may greatly influence the thermodynamic stability of nanoparticles. Thus, in the work, we are extracting surface energy of a series of nanosized lanthanide titanite pyrochlores (RE2Ti2O7, RE = Gd, Y, Ho, Tm, Lu) from experiments, including high temperature drop solution oxide melt calorimetry (for enthalpy of formation), XRD and BET (for crystalline and grain sizes). Then, I will discuss how the thermodynamic picture of these nanosized pyrochlores may be related to their radiation resistance.