Low-temperature CO oxidation over manganese, cobalt, and nickel doped CeO2 nanorods

Abstract

Surface active sites such as oxygen vacancies, Ce³⁺ ions, and unsaturated coordinated sites on nano ceria (CeO₂) are significant in catalytic oxidation reactions. The recent development in nanoengineered CeO₂ made a pathway to extend its use in various catalytic applications. In this study, transition metals (Mn²⁺, Ni²⁺, and Co²⁺) doped CeO₂ nanorods (NRs) were prepared by hydrothermal method and tested towards CO oxidation. Furthermore, the samples were characterized by various physicochemical techniques, namely, TEM and HR-TEM, SEM-EDX, XRD, ICP-OES, BET surface area, Raman spectroscopy, XPS, and H₂-TPR. The results demonstrated that the incorporation of dopants greatly enhances the surface defective sites (Ce³⁺ ions and a high degree of surface roughness) and redox properties of CeO₂ NRs and thereby improved catalytic activity. Especially, the Co–CeO₂ NR catalyst exhibited better CO conversion (T₅₀ ∼ 145 °C) when compared to pure CeO₂ NR (T₅₀ ∼ 312 °C).