Mechanochemical activation of CeO₂ in order to boost physicochemical properties for catalytic applications

Mechanochemical activation, by means of high-energy ball milling, was applied to CeO₂ as a strategy to enhance its physicochemical properties. Different milling parameters such as rotational speed and milling time were screened to evaluate their effect on ceria. Fluorite-type structure of cerianite was maintained in all cases, no matter the amount of energy introduced by milling process, as observed by X-ray Diffraction (XRD). A decrease in crystallite sizes along with a consequent increase in Specific Surface Area (S_BET) were observed by XRD and N₂ sorption (BET method). Pore diameters and total pore volumes were also in line with the duration of CeO₂ milling. Moreover, redox properties and oxygen mobility studied by H₂-Temperature Programmed Reduction (H₂- TPR) showed an increase in reducibility with milling time, including signals of both bulf and surface ceria, due to the greater number of defects and/or oxygen vacancies achieved by mechanochemical activation. Obtained features could play an essential role in terms of metal-support interaction, reactants adsorption and/or oxygen supply during catalytic reactions. Thus, high-energy ball milling becomes a useful, simple and green method for materials design with catalytic applications.