Size-dependent decomposition temperature of nanoparticles: A theoretical and experimental study

Thermal decomposition of nanomaterials is often involved in the preparation and applications of nanomaterials, of which decomposition temperature can be surprisingly different from corresponding bulk materials. However, there is a lack of theoretical and experimental investigation on the relationship between the decomposition temperature and nanoparticle size. In present study, the relation between the decomposition temperature and the size of nanoparticles was derived theoretically, which indicates that the decomposition temperature decreases with the size of the nanoparticles decreasing, and there is a linear relationship between the decomposition temperature and the reciprocal of the particle size when the radius is bigger than 10 nm. Thermal decomposition experiments of nano-calcium carbonate with different sizes were carried out by thermo-gravimetric (TG), the onset decomposition temperatures (Tonset) and the temperature of the DTG peaks (Tmax) were measured and both of them present well liner relationship with the reciprocal of the particle size. The depress regularity of the onset decomposition temperature of nano-calcium carbonate agrees with the derived thermodynamic relationship. This thermodynamic theory provides a quantitative description for the decomposition temperature of nanoparticles, also it can be used to predict and explain the thermal decomposition behavior of nanomaterials.