TY  - JOUR
TI  - Oxygen vacancies on $Pd/TiO_2$ are detected at low pressures by ESR spectroscopy at ambient temperatures
AB  - A low field benchtop electron spin resonance (ESR) (also referred to as electron paramagnetic resonance (EPR)) spectrometer is used to reveal paramagnetic centres such as oxygen vacancies and $Ti^{+3}$ centres over 0.5%Pd/$TiO_2$. The measurement was performed at room temperature after the sample was reduced in situ under mild hydrogen pressures and evacuated to P < 10–6 Torr. The measurement was possible due to a $T_1$ compensation effect under vacuum: Correlation times at low pressures enabled sufficient line narrowing and detection of the ESR signal, justifying a method using benchtop spectrometers coupled to vacuum manifolds. The method justification was demonstrated using similar measurements performed on a reference compound, Mn(II) in plasticine: a measurement performed by saturation recovery technique revealed that $T_1$ of the signal due to Mn(II) was smaller in vacuum than its atmosphere exposed counterpart. By applying vacuum, the ESR spectra of 0.5%Pd/$TiO_2$ were collected at ambient temperatures, with features equivalent to the published data obtained at cryogenic temperatures.
AU  - Yarar, Melis
AU  - Uner, Deniz
DO  - 10.55730/1300-0527.3416
PY  - 2022
JO  - Turkish Journal of Chemistry
VL  - 46
IS  - 4
SN  - 1300-0527
SP  - 1081
EP  - 1088
DB  - TRDizin
UR  - http://search/yayin/detay/1141981
ER  -