Dynamic Nuclear Polarization NMR of Low‑γ Nuclei: Structural Insights into Hydrated Yttrium-Doped BaZrO_3

Abstract

We demonstrate that solid-state NMR spectra of challenging nuclei with a low gyromagnetic ratio such as yttrium-89 can be acquired quickly with indirect dynamic nuclear polarization (DNP) methods. Proton to ^(89)Y cross polarization (CP) magic angle spinning (MAS) spectra of Y^(3+) in a frozen aqueous solution were acquired in minutes using the AMUPol biradical as a polarizing agent. Subsequently, the detection of the ^(89)Y and 1H NMR signals from technologically important hydrated yttrium-doped zirconate ceramics, in combination with DFT calculations, allows the local yttrium and proton environments present in these protonic conductors to be detected and assigned to different hydrogen-bonded environments.