This study investigates the structural, pressure distribution, and hydrogen adsorption properties of PdNAg(42-N) Pt13 trimetallic nanoalloys (N = 5, 6, 7) with icosahedral symmetry. The structural configurations were optimized using Gupta potentials, followed by density functional theory (DFT) relaxations for validation. The results reveal that Pd atoms preferentially occupy edge positions on the (111) facets, with Pt forming a stable 13-atom icosahedral core and Ag atoms occupying the remaining surface sites. The hydrogen adsorption strength on the (111) facets, which are composed of silver atoms and exhibit the highest average tensile pressure, is directly related to the presence of Pd atoms in the neighboring regions of these surfaces. Additionally, the 111 facets, characterized by a single Pd atom at the edge site and experiencing the weakest local tensile pressures, were found to be less favorable for hydrogen adsorption. These findings suggest that increasing the Pd content in Pd-Ag-Pt nanoalloys could enhance their catalytic activity and hydrogen storage capabilities, providing valuable insights for future energy applications.