Rb_jM_k[Fe(CN)₆]_l (M = Co, Ni) Prussian Blue Analogue Hollow Nanocubes: a New Example of a Multilevel Pore System

A facile surfactant-free route to synthesize uniform Rb_0.4M₄[Fe­(CN)₆]_2.8·7.2H₂O (M = Co, Ni) hollow nanoparticles is described. Rb_1.6Mn₄[Fe­(CN)₆]_3.2·4.8H₂O serves as a sacrificial/removable core in the synthesis of core@shell heterostructures. After dissolution of the cores under very mild conditions, the crystalline hollow nanocubes feature well-defined micro-, meso-, and macropores. The surfactant-free approach preserves the reactivity of the Prussian blue analogue surface as evidenced by the subsequent synthesis of hollow shell@shell heterostructures.