Recent advances in the understanding of the direct conversion of soot: and NO on Fe2O3 catalyst in diesel exhaust

摘要

This article reviews the fundamentals of the catalytic reaction of soot and NO in diesel exhaust to form N2 and CO2 focussing on the model catalyst Fe2O3. It was found out that the soot/NO reaction is a side reaction of the soot/O2 conversion, in which the Fe2O3 catalyst acts as oxygen pump transferring oxygen from the gas-phase via its surface to the soot. However, the catalyst is not directly involved in the soot/NO reaction other than increasing the number of C* sites. These sites were considered to be responsible for the NO reduction on the soot facilitating the dissociation of NO and formation of N2. Based on this mechanism a global-kinetic model was constructed.