Large-scale syntheses of Prussian Blue (PB) uniform nanocubes and nanospheres, together with all interesting PB micro-frame structure, have been achieved by direct dissociation of a single-source precursor K-3[Fe(CN)(6)] with polyvinylprrolidone (PVP) as a capping and reducing agent. The reaction temperature has been proved to be a key factor for morphology development of PB nanocrystals, and the size of PB nanocrystals can be tuned by adjusting the feed ratio of K3[Fe(CN)(6)] to PVP and the concentration of K-3[Fe(CN)(6)]. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and high resolution transmission electron microscopy (HRTEM) were used to characterize the resulting nanocrystals and investigate their growth mechanisms. Optical and magnetic studies showed size- and shape-dependent optical and magnetic properties in the PB nanocrystals. An excellent electro-catalytic Property to hydrogen peroxide reduction was observed at the PB nanocube-modified electrode. (c) 2008 Elsevier Inc. All rights reserved.