Designed Y(3+) Surface Segregation Increases Stability of Nanocrystalline Zinc Aluminate

[Image: see text] The thermal stability of zinc aluminate nanoparticles is critical for their use as catalyst supports. In this study, we experimentally show that doping with 0.5 mol % Y(2)O(3) improves the stability of zinc aluminate nanoparticles. The dopant spontaneously segregates to the nanoparticle surfaces in a phenomenon correlated with excess energy reduction and the hindering of coarsening. Y(3+) was selected based on atomistic simulations on a 4 nm zinc aluminate nanoparticle singularly doped with elements of different ionic radii: Sc(3+), In(3+), Y(3+), and Nd(3+). The segregation energies were generally proportional to ionic radii, with Y(3+) showing the highest potential for surface segregation. Direct measurements of surface thermodynamics confirmed the decreasing trend in surface energy from 0.99 for undoped to 0.85 J/m(2) for Y-doped nanoparticles. Diffusion coefficients calculated from coarsening curves for undoped and doped compositions at 850 °C were 4.8 × 10(–12) cm(2)/s and 2.5 × 10(–12) cm(2)/s, respectively, indicating the coarsening inhibition induced by Y(3+) results from a combination of a reduced driving force (surface energy) and decreased atomic mobility.