Stability of supported metal and supported metal oxide combustion catalysts

Catalysts used for high-temperature combustion of light hydrocarbons must m aintain high activity over long time intervals by avoiding excessive sinter ing and deactivation in the hot and corrosive combustion environment. The s intering resistance and chemical stability of catalytically active phases i s a key technical problem that must be solved for the development of commer cially viable combustion catalysts. All noble metals and transition metal o xides that are catalytically active rapidly sinter at temperatures required for high combustion rates. Advanced materials used in the development of s table catalysts include highly sintering-resistant hexaaluminate supports f ar dispersion of noble metals, chemically and thermally stable supporting o xides for active transition metal oxides, and single-phase, substitutionall y activated, sintering-resistant complex metal oxides. This paper will revi ew deactivating phenomena, such as sintering and vapor transport and assess recent progress in the development of durable combustion catalysts. (C) 19 99 Elsevier Science B.V. All rights reserved.