Temperature-programmed reduction (TPR) and temperature-programmed oxid
ation (TPO), combined with differential thermal analysis (DTA) and FT-
IR spectroscopy, were used to characterize trimanganese tetroxide cata
lysts. It was found that the redox behavior of Mn3O4 Was considerably
affected by different gas treatments, preparative condition and the ad
dition of a promoter. A possible interpretation of two reduction peaks
in the TPR profile of Mn3O4 has been suggested.