(a) TEM picture of the Rh nanoframes obtained by selective etching of the Pd cores from the Pd–Rh core–frame NCs; (b) corresponding steps of formation: (1) selective nucleation of Rh; (2) formation of bimetallic Pd–Rh core–frame concave NCs; (3) formation of cubic Rh nanoframes by selectively etching away the Pd cores. Adapted from ref. 55 with permission from John Wiley & Sons, Copyright 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.