Effects of oxide-shell structures on the dynamics of oxidation of Al nanoparticles

Effects of the crystalline and amorphous structure of alumina shells on the dynamics of oxidation of an aluminum nanoparticle (ANP) are studied using multimillion-atom molecular dynamics simulations. With an amorphous shell, formation of oxidized nanocluster fragments produced by the shattering of the shell, combined with the fragmentation and dispersion of the nanoparticle, catalyzes faster oxidation reactions. Consequently, the energy release rate of an ANP with an amorphous shell is much higher than that with a crystalline shell. Analysis on the formation of oxygen-rich fragments further confirms an enhanced reaction rate with an amorphous shell.