We report a 23 Na and 27 Al nuclear magnetic resonance (NMR) investigation of low-silica X (LSX) zeolite with chemical formula Na12Al12Si12O48 (Na12-LSX) loaded with n additional guest sodium atoms. Nan/Na12-LSX exhibits an insulator-to-metal transition around n = 11.6, which is accompanied by a significant enhancement of bulk magnetic susceptibility. Paramagnetic moments are thermally activated in the metallic Na12/Na12-LSX with an activation energy of around 0.1 eV. At the same time, a new shifted component (SC) appears in the 23 Na NMR, whose large and positive NMR shift scales with bulk magnetic susceptibility. Its spin-lattice relaxation rate 1/T1 is governed by the fluctuations determined by the same activation energy as obtained from the bulk magnetic susceptibility data. The timescale of these fluctuations is typical for atomic motions, which suggest strong electron-phonon coupling, a hallmark of polaron states. The insulator-to-metal transition in Nan/Na12-LSX is thus discussed within a polaron model.

No abstract

No abstract

For the first time, the oxygen reduction reaction was studied on WTe2 transition metal dichalcogenide with Te vacancy.