Internal structure of Al hollow nanoparticles generated by laser ablation in liquid ethanol

► Aluminium hollow nanoparticles were prepared by laser ablation of an Al target in liquid ethanol saturated with H2. ► A distinct core-shell structure with a single crystal fcc Al core has been evidenced. ► A novel mechanism has been proposed to explain the formation of the inner cavity that takes into account the sharp dependence of H2 solubility in Al with temperature.