Pd encapsulation in automotive exhaust-gas catalysts

Abstract

Raman spectroscopy was used to detect strained PdO in fully formulated Pd-based automotive exhaust-gas catalysts that had been subjected to high-temperature accelerated aging treatments. The presence of strained PdO provides evidence of Pd encapsulation by ceria-zirconia, as in a previous study of a model powder catalyst. The relationship between strained PdO and Pd encapsulation was further examined for other model catalysts, and major factors influencing the application of this detection method were identified.