  The application of nanocrystals as heterogeneous catalysts and plasmonic
nanoparticles requires fine control of their shape and chemical composition. A
promising idea to achieve synergistic effects is to combine two distinct
chemical and/or physical functionalities in bi-metallic core-shell
nanocrystals. Although techniques for the synthesis of single-component
nanocrystals with spherical or anisotropic shape are well established, new
methods are sought to tailor multicomponent nanocrystals. Here, we probe
etching in a controlled redox environment as a synthesis technique for
multi-component nanocrystals. Our Monte Carlo computer simulations demonstrate
the appearance of characteristic non-equilibrium intermediate microstructures
that are further thermodynamically tested and analyzed with molecular dynamics.
Convex platelet, concave polyhedron, pod, cage and strutted-cage shapes are
obtained at room temperature with fully coherent structure exposing
crystallographic facets and chemical elements along distinct particle
crystallographic directions. We observe that structural and dynamic properties
are markedly modified compared to the untreated compact nanocrystal.
