It is shown that the hybrid nanocomposites based on conducting polymers (СP), doped with Keggin heteropolyacids (HPA), and transition metal oxides (V2O5, TiO2, Co3O4) as well as their bifunctional analogues, which additionally contains up to 5 wt. % of nanosized platinum or palladium can act as electrocatalysts for oxygen reduction for hydrogen-oxygen fuel cells.
It is established that the activity of nanocomposite electrocatalysts in the oxygen reduction reaction (ORR) is effect of the set and the mutual influence of the catalytic action of all composite components and depends on the chemical nature of the oxide, CP and HPA, the presence in composites of nanosized Pt or Pd, as well as the pH of the electrolyte. The explanation for a significant increase in electrocatalytic activity of bifunctional nanocomposites compared with counterparts that do not contains nanosized platinum was proposed.
The biohybrid electrocatalysts ORR based on CP and enzymes – laccase (Lac) and peroxidase (HRP) were obtained. It is established that in composites based on Lac enzyme provides the activation and reduction of oxygen on a 4-electron mechanism, and hybrid electrocatalysts based on HRP capable to reduction of O2 and the product of its 2-electron reduction (H2O2), which increases the efficiency of hybrid electrocatalysts.
The effective methods of applying catalytic layers based on hybrid composites on porous carbon paper Toray (simultaneously serving gaseous diffusion substrate and the catalyst support) was developed and their main electrocatalytic properties in ORR in fuel half-cell (paper Toray|electrocatalyst|electrolyte) was established.
Keywords: nanocomposites, electrocatalysts, oxygen reduction, hydrogen-oxygen fuel cells, conducting polymers, enzymes, oxides, physical and chemical properties.