Introduction to the Catalytic Combustion of Diesel Soot

Abstract

The heterogeneous catalytic reaction containing solid particle as reactant is a class of important and complex chemical reaction. The solid particles such as soot emitted from diesel engines, are becoming increasingly important in the context of cleaning air and lowering automotive emissions. Diesel soot particulates are defined by the US Environmental Protection Agency (EPA) as “all compound collected on a pre-condition filter in diluted diesel exhaust gases at a maximum temperature of 50°C”. The catalytic combustion is considered as one of effective method for purifying these diesel soot pollutants. Supported oxide catalysts were originally developed for the catalytic combustion, but they are not especially active at low temperatures (<400°C) under the loose contact condition between catalysts and soot [1,2]. Noble metal catalysts such as platinum and gold, on the other hand, are efficient and exhibits high activity [3,4]. However, Pt is very expensive and causes the great emissions of sulfates. Thus, the development of active and stable catalysts without noble metals for the catalytic combustion of soot particles at low-temperature remains a significant challenge.