Atmosphere-dependent stability, mobility and CO oxidation performance of Pt single atoms and clusters on γ-alumina

Abstract

SSCI-VIDE+ECI2D:ING+DEC:FMO:JRO:PAF:LPINational audienceIn this work, the stability of γ-alumina-supported single Pt atoms formed by oxidative treatment of an impregnated Pt precursor has been monitored by operando X-ray absorption spectroscopy (XAS). Their destabilization into subnanometric clusters under reductive treatment has been studied by XAS and environmental scanning transmission electron microscopy (E-STEM). DFT calculations allow us to fully rationalize these behaviors in terms of nuclearity and adsorbate coverage (O or H), which governs the cluster size, shape and interaction with the support.Pt/γ-Al2O3 SACs were also submitted to CO oxidation heating/cooling cycles separated by a reduction treatment and the catalysts were analyzed by operando DRIFTS, operando XAS and STEM