Femtosecond laser irradiation in CeO2 samples and advances in theoretical approach

Abstract

CeO2 nanostructures have proved to be extremely important in application as a CO gas sensor due to extreme gas selectivity. It is observed from recent works that the surface to which the material is exposed has fundamental importance to the electrical properties. The objective of this project is two-fold: i) to study the femtosecond laser irradiation on CeO2 and CeO2/NiO particles with different morphologies (rods, beans and polyhedrons) and ii) to carry out, based on first principle calculations, to complement and rationalize the experimental results. The interaction of the femtosecond laser irradiation with materials induces the formation of metallic nanoparticles from the bulk of the material, thus altering its stoichiometry and generating different types of defects, which will be studied as a function of the CeO2 sensing properties. Theoretical studies by means of density functional theory (DFT) developed in the Laboratory of Theoretical and Computational Chemistry coordinated by Prof. Dr. Juan Andrés will allow to obtain a deeper insight and knowledge to understand the sensing behavior of the non-stoichiometry oxide. We intend to analyze the different surfaces of CeO2 already obtained experimentally as a function of surface energy, band gap energy, band structure and state density, besides studying the CeO2/NiO system. Experimentally modified samples will be analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Transmission electron microscopy (TEM) techniques, and will be correlated with theoretical studies in order to provide a better understanding of the physical and chemical properties of these systems. (AU)