In-situ Transmission Electron Microscopy and Density Functional Theory Study of the Reduction of MoO3 Nanoparticles

Abstract

Molybdenum trioxide (MoO3) nanoparticles were heated using in-situ transmission electron microscopy (TEM), causing the nanoparticles to disintegrate into smaller flakes. These nanoparticle flakes were shown to be MoO2 and Mo4O11. The MoO3 nanoparticle also exfoliated partly before reducing. The findings from the heating were investigated with density functional theory (DFT) calculations using the Vienna ab initio simulation package (VASP). It was found that the reduction to neither MoO2 nor Mo4O11 is favourable at 0 K, but the temperature raise and the vacuum of the TEM probably shift the equilibrium so that the reduction takes place. It was found that the formation of Mo4O11 probably happens in a side reaction, such that the MoO3 reduction to MoO2 is a one-step reaction. The exfoliation energy was calculated and the disintegration of the nanoparticle was concluded to be caused by the large lattice mismatch of the MoO3/MoO2 interface.