Size and shape dependent thermal properties of rutile TiO2 nanoparticles: a molecular dynamics simulation study

Abstract

ABSTRACTMolecular dynamics (MD) simulations, based on a recently developed charge optimised many-body interatomic potential (COMB3) for titanium dioxide materials, have been employed to investigate the effects of size and shape on the thermal properties of rutile TiO2 nanoparticles (2–6 nm). The size and shape dependence of the melting temperature, cohesive energy, heat capacity and thermal expansion coefficients have been studied. Our MD simulation results show that the melting point of spherical nanoparticles increases with size increase. On the other hand, the heat capacity and thermal expansion coefficients decrease with increasing nanoparticle size. Also, to predict the thermal properties of rutile TiO2 nanoparticles, we merged two theoretical models (Qi-model and Zhu’s model) proposed for size and shape-dependent thermal properties of nanoparticles. The comparison between our MD simulation results with those predicted by theoretical models showed that the trends observed in our MD simulation results were in good agreement with those suggested by the theoretical models. However, the thermal properties obtained from MD simulations deviated from those calculated theoretically for small nanoparticles which could be due to the edge and corner effects disregarded in the theoretical model.