Re-dispersion of Pd-based bimetallic catalysts by hydrothermal treatment for CO oxidation

Abstract

The Pd/CeO₂ catalyst, which is highly active catalyst in automobile emission control especially for CO oxidation, often suffers from severe sintering under harsh condition, specifically hydrothermal treatment. Here, we report re-dispersion of Pd-based bimetallic (Pd–Fe, Pd–Ni, and Pd–Co) catalysts deposited on ceria by hydrothermal treatment at 750 °C using 10% H₂O. The re-dispersion was confirmed by various characterization techniques of transmission electron microscopy, CO chemisorption, CO-diffuse reflectance infrared Fourier transform, CO-temperature programmed desorption, and X-ray absorption spectroscopy. The dispersion of Pd increased significantly after hydrothermal treatment, resulting in improved CO oxidation activity. The presence of secondary transition metals enhanced the CO oxidation activity further, especially hydrothermally treated Pd–Fe bimetallic catalyst showed the highest activity for CO oxidation.