Oxygen vacancies on Pd/TiO are detected at low pressures by ESR spectroscopy at ambient temperatures.

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 centres over 0.5%Pd/TiO. The measurement was performed at room temperature after the sample was reduced under mild hydrogen pressures and evacuated to P < 10 Torr.