Applied Catalysis A-general | 2019
Three-way catalytic performance of Fe-doped Pd/CeO2-ZrO2 under lean/rich perturbation conditions
Abstract
Abstract Oxygen storage capacity (OSC) of Pd/CeO2-ZrO2 was significantly improved by addition of transition metals (Ni, Fe, Co, Cu, Sn, Ga, In). Reducible transition metal, such as Ni, Fe, Cu, Co and Sn - doped Pd/CZ showed quite higher OSC than the theoretical value assumed the complete redox of Ce4+ ⇔ Ce3+ (250 mmol-O2 mol-CeO2−1), suggesting the participation of transition metal in reversible oxygen release/sorption. Fe and Sn were effective additives to achieve high OSC property. No significant increase in the three-way catalytic activity of Pd/CeO2-ZrO2 under the stoichiometric conditions was achieved by the addition of transition metals. However, Ni, Co, Fe, and Ga – doped Pd/CeO2-ZrO2 showed higher TWC performance than Pd/CeO2-ZrO2 under the lean/rich perturbation conditions. From H2-TPR and FT-IR spectroscopy following CO adsorption, the role of Fe additive was concluded to be the creation of easily reducible Pd species interacting with Fe-doped CeO2-ZrO2 and then to be the stabilization of Pd species in the catalytically active reducing state under the reaction conditions.