Designed Y3+ Surface Segregation Increases Stability of Nanocrystalline Zinc Aluminate

Autor(es)

Martin, Luis E. Sotelo ; O'Shea, Nicole M. ; Mason, Jeremy K. ; Castro, Ricardo H. R.

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry C; v. N/A, p. 12-pg., 2023-02-02.

Resumo

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 % Y2O3 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. Y3+ was selected based on atomistic simulations on a 4 nm zinc aluminate nanoparticle singularly doped with elements of different ionic radii: Sc3+, In3+, Y3+, and Nd3+. 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 degrees C were 4.8 x 10(-12 )cm(2)/s and 2.5 x 10(-12) cm(2)/s, respectively, indicating the coarsening inhibition induced by Y3+ results from a combination of a reduced driving force (surface energy) and decreased atomic mobility. (AU)

• Processo FAPESP: 22/04150-6 - Estudo de nanocerâmicas para aplicação em energia: sinterização e interfaces
• Beneficiário: Flavio Leandro de Souza
• Modalidade de apoio: Auxílio à Pesquisa - Pesquisador Visitante - Internacional