Comparative catalytic activity of PET track-etched membranes with embedded silver and gold nanotubes

Abstract

Irradiated by heavy ions nanoporous polyethylene terephthalate track-etched membranes (PET TeMs) after +15Kr84 ions bombardment (1.75MeV/nucl with the ion fluency of 1×109cm−2) and sequential etching was applied in this research as a template for development of composites with catalytically enriched properties. A highly ordered silver and gold nanotubes arrays were embedded in 100nm pores of PET TeMs via electroless deposition technique at 4°C during 1h.All “as-prepared” composites were examined for catalytic activity using reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by sodium borohydride as a common reaction to test metallic nanostructures catalysts. The effect of temperature on the catalytic activity was investigated in range of 292–313K and activation energy were calculated. Kapp of Ag/PET composites linearly increase with an increase of the temperature thus normal Arrhenius behavior have been seen and the activation energy was calculated to be 42.13kJ/mol. Au/PET composites exhibit not only more powerful catalytic activity but also non-linear dependence of rate constant from temperature. Kapp increased with increasing temperature throughout the 292–308K temperature range; the reaction had an activation energy 65.32kJ/mol. In range 311–313K rate constant dramatically decreased and the apparent activation energy at this temperature rang was −91.44kJ/mol due some structural changes, i.e. agglomeration of Au nanoparticles on the surface of composite.