Structural, photoluminescent and electrochemical properties of self-assembled Co3[Co({CN})6]2/{ZnO} nanocomposite

Advanced functional nanocomposites designed for multiple applications can be developed using supramolecular chemistry. In this work, we report the synthesis and characterization of nanosized composite material (Co3[Co (CN)6]2/ZnO) formed by cobalt Prussian blue analogue (Co3[Co(CN)6]2) and zinc oxide nanoparticles (ZnO NPs). Structural, morphological and optical characterization, supramolecular arrangement, and electrochemical properties of the materials were investigated. Based on TEM results, Co3[Co(CN)6]2/ZnO predominantly pre-sented a size-polydisperse cube-shaped morphology. A decrease of the nanocomposite mean particle diameter relative to Co3[Co(CN)6]2 was observed. Similar behavior was confirmed by dynamic light scattering with decrease of hydrodynamic diameter value after nanocomposite formation. The Co3[Co(CN)6]2 and Co3[Co (CN)6]2/ZnO exhibited potential zeta values at-69.5 and-59.6 mV respectively suggesting superficial negative character and excellent colloidal stability, even after ZnO NPs incorporation. The electronic spectral of UV-Vis region exhibited semiconductor properties of the nanocomposite despite the presence of the cobalt complex. Interesting that Co3[Co(CN)6]2/ZnO showed a voltammetric profile with two redox pair with E1/2 values of 0.46 and 0.54 V attributed to the Co+/Co2+ and Co2+/Co3+, respectively, and an irreversible reduction process at-0.74 V attributed to Zn2+/Zn0 species, which differ from the electrochemical processes observed for individual componentes, Co3[Co(CN)6]2 (E1/2 = 0.40 V) and ZnO species (Epc =-0.74 V). The electron transport study of the nanocomposite indicated that the both electrochemical redox processes were controlled by diffusion and adsorption.