Influence of nanoparticle shape on hydrogen absorption in Palladium: A combined DFT and atomistic approach

The absorption of hydrogen atoms into Palladium nanoparticles is studied employing Density Functional Theory (DFT) and atomistic simulations. Three experimentally reproducible nanoparticle shapes – -decahedral, icosahedral, and cuboctahedral – are considered, all in the same size range but with distinct structural properties. Where possible, we highlight the connections of the absorption energy with the structural and electronic properties of the different tetrahedral and octahedral absorption sites on the nanoparticles. We show that the strain engineering of nanoparticles achieved by modifying the host nanoparticle can be used, in principle, as a tool to favor hydrogen absorption with potential practical applications. Additionally, we study how the placement of many hydrogen atoms in the surface and subsurface of the icosahedral nanoparticle modifies the absorption in other sites. We show that the surface can undergo a reconstruction for high hydrogen loading while the overall geometry is maintained.