Diesel particulate filtration and combustion in a wall-flow trap hosting a LiCrO2 catalyst

This paper concerns the development of an innovative LiCrO2 catalyst (synthesis, characterization, mechanistic analysis, and aging). This catalyst already showed appreciable activity at 300 degrees C toward the catalytic combustion of soot even under loose contact conditions. Furthermore, its limited sensitivity to hydrothermal aging in the presence of SO2 at 650 degrees C demonstrated a favorable result for its possible application in catalytic traps for diesel particulate removal from car exhaust gases. In this perspective, an in situ combustion synthesis method was tailored to the preparation of a LiCrO2-catalyzed trap based on a SiC wall-flow monolith. Engine bench tests on this catalytic trap (trap loading and regeneration inducing a temperature increase by the catalytic combustion of suitably postinjected fuel) showed that the presence of the catalyst in the wall-flow trap enabled both a more complete regeneration and a 2-fold reduction of the regeneration time compared to the case of a noncatalytic trap, with the consequent saving of postinjected fuel.