About the Active Phases of KNO3/Mgo for Catalytic Soot Combustion

JIMÉNEZ, R.; GARCÍA, X.; GORDON, A.
Reaction Kinetics and Catalysis Letters 99 281-287, 2010.

DOI: 10.1007/s11144-009-0145-7

Abstract

Reports suggest KNO₃ as the active phase for the catalytic combustion of soot, through a redox mechanism with KNO₂. Previously, the high activity of KNO₃ for coal gasification (mechanism similar to that of soot combustion) was attributed to decomposition into active K_xO_y (y < x) compounds. In this work, TGA-MS assays of carbothermic reduction using the KNO₃/MgO catalyst showed decomposition into NO_x, (to which starting of CB combustion is attributed) and potassium oxide, thus disregarding possible redox cycles KNO₃/KNO₂. Consecutive assays of carbothermic reduction and TPO in a fixed bed reactor showed the potassium oxides as the main active phases of these catalysts.