The nucleation sites for BaO on γ-Al2O3 studied by high sensitivity LEIS

Introduction The extreme surface sensitivity of Low Energy Ion Scattering (LEIS) enables a nondestructive (static) and quantitative analysis of the outermost atoms of the surface. Using highsensitivity LEIS low loadings of the active phase on a highly dispersed support can be detected [1]. For oxidic spinels it was found that only the cations that are present in the octahedral sites are at the outer surface, while the cations in the tetrahedral sites reside just below this surface. A 1:1 correlation between LEIS and catalysis was demonstrated for the selective reduction of nitroto nitrosobenzene [2]. Techniques such as XPS, that probe much deeper, do not show this correlation.