Negative Surface Energies of Nickel Ferrite Nanoparticles under Hydrothermal Conditions

Figure 2

(a) Surface formation energies for the bare and hydroxylated nickel ferrite (111) surfaces as a function of temperature and pH value. The exotermicity of the H₂O adsorption process decreases with temperature. (b) Free energy of formation for bulk nickel ferrite as a function of temperature and pH. As the temperature and pH increase, the bulk becomes more stable.

(a)

(b)