S. Christoskova et al., STUDY ON THE THERMAL-STABILITY OF A HIGH CO-OXIDE USED AS LOW-TEMPERATURE CATALYST AND OXIDANT FOR COMPLETE OXIDATION, Thermochimica acta, 292(1-2), 1997, pp. 77-83
A new higher Co-oxide has been synthesized. Its features are presented
by means of IR-spectroscopy, X-ray analysis, XPS-spectroscopy, EPR, m
agnetic measurements and chemical analysis in a separate paper by the
present authors. On the grounds of the obtained results the following
formula, determining the content of the higher Go-oxide, has been put
forward. Co1-x+2Cox+4Oy(OH)(y) . mH(2)O, with the Co-ions being in the
ir highest oxidation degrees (i.e. +4) and in an octahedral position.
The synthesized Go-oxide system can be utilized as an active phase of
a low-temperature catalyst as well as a strong oxidant for a complete
oxidation in liquid and gas mediums. The present paper also studies th
e thermal stability of the synthesized Co-oxide system by means of the
rmal analysis, IR-spectroscopy, X-ray and chemical analysis. The resul
ts show that both the freshly obtained higher Co-oxide and the thermal
ly treated (up to 250 degrees C) samples maintain their composition, s
tructure and activity in the oxidation processes. Heated at temperatur
e above 250 degrees C, the Co-oxide system undergoes changes in its co
mposition and structure, turning it into a cobaltite with a spinel str
ucture. This is the reason for the sharp decrease of the activity of t
he studied system in the oxidation processes. (C) 1997 Elsevier Scienc
e B.V.