Shmychkova O. Electrochemical formation of PbO2-based composites and their electrocatalytic properties

The work concerns the establishment of general formation regularities of PbO2-surfactant (polymer) composites with a given composition; the identification of additives effect on the deposition kinetics, composition, physicochemical properties, electrocatalytic activity and selectivity of composites to oxidation of aromatic contaminants. It was found that there is a slight decrease in α-phase PbO2 within 10% in both nitrate and methanesulfonate electrolytes with increasing length of the carbon chain of anionic surfactants with high surface activity (sodium dodecyl sulfate and laureth sulfate) and fluorine-containing surfactants. Therefore, the minimum content is observed for PbO2-sodium laureth sulfate and PbO2-perfluorohexane sulfonate coatings containing 16 and 8 carbon atoms, respectively. An express method of semi-quantitative assessment of the phase composition of coatings has been proposed, which is based on the analysis of the oxide reduction on the inversion voltammogram. It is shown that in contrast to surfactants, there is an extreme dependence of the heterogeneous deposition rate constant vs. the additive concentration in the presence of Nafon® polymer. It is shown that use of surfactants and polyelectrolytes, as well as the aggregately stable suspension electrolytes with nanosized particles of the dispersed phase and surfactants, one can get the novel composites (metalloxide-surfactant (polymer) and ternary systems PbO2-TiO2-surfactant), which differ significantly in composition. Variation in the deposition conditions allows one to change the content of additives in composites from 1 to 18 wt.%, which enables directed affection on morphology, texture, phase composition, physicochemical properties, electrocatalytic activity and selectivity of electrocatalysts based on PbO2 in target processes.