3D-TEM investigation of the nanostructure of a δ-Al2O3catalyst support decorated with Pd nanoparticles

Abstract

The electron tomography technique applied in a quantitative way allowed us to characterize a heterogeneous catalyst made of Pd nanoparticles deposited on a δ-Al₂O₃ lamellar support. In the first step, high resolution tomographic experiments carried out on several typical areas of support have confirmed the hypothesis of formation of δ-Al₂O₃ proposed in the literature by the coalescence of lateral facets of the γ-Al₂O₃ precursor. A bimodal porosity was also observed in the arrangement of δ-Al₂O₃ platelets. In the second step, the Pd nanoparticles were found preferentially anchored on the lateral facets of δ-Al₂O₃ platelets or on the defects situated on their basal planes. From a general point of view, we have demonstrated once again that the electron tomography technique implemented with nanometre resolution provides unique insight into the structure, morphology and spatial arrangement of components in a complex 3D nanostructure.