Automotive Exhaust Catalyst Multi-functionalized by Addition of Basic Materials

摘要

It is well known that 3-way catalysts are used for control of automotive exhaust, which include the emission of toxic gases, carbon monoxide(CO), hydrocarbon(HC), and nitrogen oxides(NOx). The catalyst is operated under atmospheric conditions where air to fuel ratios(A/F) fluctuate, because only the average A/F is automatically kept close to the stoichiometric value. The 3-way catalysts are formulated from many components such as noble metals for the active site, oxides to work as promoter, and support to provide a large surface area. Recently, by addition of basic materials, the performance of 3-way catalysts has been improved significantly improved and multi-functionalized. In this paper, palladium(Pd) 3-way catalyst and NOx storage-reduction 3-way catalyst and the effect of basic material addition on catalytic activity for the 3-way catalyst are summarized.