Preparation of Rh/CeO₂ Using Supercritical CO₂ and Its Catalytic Application for Automotive Exhaust

Abstract

Rh/CeO₂ catalysts were investigated for automotive catalysts prepared by a supercritical CO₂ impregnation technique. Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used for the analysis of the Rh loading, Rh structure, and the morphology of the particles, respectively. Results of TEM and XRD showed Rh particles are highly dispersed on CeO₂ surface, and Rh/CeO₂ after calcination were prevented aggregation of CeO₂. OSC of Rh/CeO₂ prepared by supercritical impregnation method was higher than those of conventional catalysts. The catalytic tests for three way catalysts (TWC) showed high CO oxidation activity obtained using Rh/CeO₂ prepared by supercritical impregnation. Thus, it was concluded that supercritical CO₂ impregnation technique can improve OSC and TWC activity.