Revealing the Effects of Electron Irradiation on PdO _<i>x</i> /CeO ₂ Catalysts Prepared by Impregnation and Ball Milling and Their Implications for CO Oxidation

This study explores the impact of electron beam irradiation (EBI) on the structural and catalytic properties of cerium dioxide (CeO2) and palladium supported on ceria (PdOx/CeO2) catalysts synthesized by incipient wetness impregnation and vibratory ball milling. All materials were subjected to controlled electron beam irradiation (10 MeV) for different absorption doses (from 2.5 to 10 MGy) and subsequently characterized using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron microscopy (SEM and HRTEM). Catalytic performance was assessed through CO oxidation as a model reaction. The results reveal significant irradiation-induced modifications in surface chemistry, crystallinity, and Pd speciation depending on the synthesis method. Notably, EBI enhanced catalytic activity across both catalyst systems, primarily through the appearance of structural defects and the formation of PdOx-Ce interfacial sites and metallic Pd species.