Structure and Composition Modification of Ultrasmall Palladium Nanoparticles upon Hydrogenation from First Principles

Abstract

Palladium-based materials exhibit a high affinity for hydrogen, making them ideal candidates for hydrogen storage or hydrogen sensing applications owing to the existence of a hydride phase. From the theoretical point of view, a bulk or slab is often used to model such systems but lacks the flexibility to adapt its lattice parameter to an increased load of hydrogen. Using density functional theory, we follow the change in the structure and composition of small palladium nanoparticles upon hydrogenation. We show that a cuboctahedral nanoparticle with hydrogen in the core and on the surface is a relevant model under experimental conditions. CO and NO are then adsorbed on this nanoparticle to highlight the crucial importance of hydrogen loading when considering palladium nanomaterials for-wider sensing applications.