Chemisorption-Driven Roughening of Hydrothermally Grown KTa_1–<i>x</i>Nb_<i>x</i>O₃ Nanoparticles

The
chemical and physical properties of nanoparticle surfaces have
significant effects on their growth processes and the resulting morphology.
Hydrothermally grown KNbO3, KTaO3, and KTa1–xNbxO3 were studied to examine the complex relationships between
surface composition, phase, chemistry, and energetics and how these
may be used to model and thereby control nanoparticle growth mechanisms.
Two different composition-dependent growth modes were identified,
where one type formed smooth surface facets, while the other resulted
in roughened nanoparticle morphologies. Electron microscopy characterization,
density functional theory calculations, and mathematical growth models
were used to illuminate the role of surface properties and chemisorption
on the nanoparticle growth morphology. Surface energy reduction by
chemisorption can increase the rate of terrace nucleation, driving
the roughening of these lower energy nanoparticle surfaces.