Monte Carlo and Molecular Dynamics simulations were employed to explore the enhanced hydrogen storage capabilities of palladium nanospheres with grain boundaries. It was found that hollow nanoparticles with grain boundaries exhibit a 20% increase in hydrogen storage capacity compared to single-crystal hollow nanospheres. The presence of grain boundaries facilitates hydrogen uptake at low chemical potentials. Isotherm analyses demonstrate a saturation point in hydrogen uptake, with the transformation of the face-centered cubic lattice into Pd hydride hollow nanostructures, followed by a volumetric increase of almost 30% of the initial volume, while maintaining mechanical stability. During the simulations, dislocation activity is suppressed by H absorption, and the contribution of shear stress is almost negligible compared to volumetric deformation. We believe that this research highlights the critical role of grain boundaries in optimizing hydrogen storage and absorption capacities on nanostructures, a crucial features for applications such as transportation and storage.