Self-assembly of nanoclusters in molybdenum blue dispersions in the presence of organic reducing agent

Molybdenum blue nanoparticles belong to the polyoxometalates (POM) containing molybdenum in oxidation states + 5 and + 6. Polyoxometalates exhibit remarkable physicochemical properties, structural flexibility and highly reactivity. These systems are considered as the most promising clusters for production of hybrid materials, drug delivery systems, nanoreactors and catalytic materials. The synthesis of nanoclusters of polyoxomolybdates is self-assembly from various initial building blocks and identification of its structure.

A study of the processes leading to the formation of particles in stable colloidal systems is necessary for more complete understanding of the synthesis of molybdenum blue as colloidal systems. The aim of this paper was to synthesize stable dispersions of molybdenum blue using organic reducing agents and investigate the self-assembly process.

Molybdenum blue dispersions were synthesized by reducing an acidic molybdate solution with glucose, hydroquinone and ascorbic acid. The influence of the H/Mo molar ratio on the rate of formation of molybdenum particles was established. For each reducing agent, the conditions for the formation of aggregative stable dispersion of nanoclusters with the maximum concentration of particles are determined. The dispersed phase is presented by toroidal molybdenum oxide nanoclusters of the class Mo_154-x, which was confirmed by the results of UV-Vis, FTIR and XPS spectroscopy, DLS and TEM.