Nanomaterials have become extremely important in applications as catalysts, sensors, batteries, etc. because of the high surface-to-volume ratio, which makes them more reactive than the macroscopic analogues. The decrease in the particle size may result in a stabilization of different structures and phase assemblages, which will subsequently affect the functions and the applications of the materials. Being their main advantage, the high surface area and the complex interfaces require a special methodology to investigate their thermodynamic properties.
The change in the thermodynamic stability fields and in the phase equilibria of several nanoparticles, nanorods, nanoneedles, and nanocomposites containing Co, Zn, Fe, Mn, and Sn will be shown as an example. High temperature oxide melt solution calorimetry in a combination with water adsorption and Thermogravimetry/Differential scanning calorimetry was used to obtain the surface energy of both hydrated and anhydrous surface.