Mechanochemical Activation of CeO2 in Order to Boost Physicochemical Properties for Catalytic Applications

Abstract

Mechanochemical activation, by means of high-energy ball milling, was applied to CeO2 as a strategy to enhance its physicochemical properties. Different milling times were screened to evaluate their effect on ceria. The fluorite-type structure of cerianite was maintained in all cases, no matter the amount of energy introduced by the milling process, as observed via X-ray diffraction (XRD). A decrease in crystallite sizes and a consequent increase in specific surface area (SBET) were observed through 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 through H2 temperature-programmed reduction (H2-TPR) showed an increase in reducibility with milling time, including signals of both bulk and surface ceria, due to the greater number of defects and/or oxygen vacancies achieved by mechanochemical activation. The obtained features could play an essential role in terms of metal–support interaction, reactant adsorption and/or oxygen supply during catalytic reactions. Thus, high-energy ball milling is a useful, simple and green method for the design of materials with catalytic applications.