Automotive catalyst deactivation: Case studies

The study of automotive catalyst deactivation is associated with technical, economic and environmental problems. The deactivation phenomenon has different origins that can be divided into three groups: thermal, chemical and mechanical deactivation. In this work, nine commercial catalysts were analyzed, seven of them aged in an engine bench. A study using scanning electron microscopy (SEM) with energy-dispersive X-ray analysis (EDS) at different positions of the monolith allowed the probable reasons for catalyst deactivation to be inferred. Thermal deactivation was a common cause for most of the samples. Other mechanisms such as washcoat losses or abrasion, contamination by sulfur and lubricants, and noble metal sintering were also observed for different samples.