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

Irradiated by heavy ions nanoporous polyethylene terephthalate track-etched membranes (PET TeMs) after Kr-+15(84) ions bombardment (1.75 MeV/nucl with the ion fluency of 1 x 10(9) cm(-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 100 nm pores of PET TeMs via electroless deposition technique at 4 degrees C during 1 h. 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 292-313 K and activation energy were calculated. K-app 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 42.13 kJ/mol. Au/PET composites exhibit not only more powerful catalytic activity but also non-linear dependence of rate constant from temperature. K-app increased with increasing temperature throughout the 292-308 K temperature range; the reaction had an activation energy 65.32 kJ/mol. In range 311-313 K rate constant dramatically decreased and the apparent activation energy at this temperature rang was -91.44 kJ/mol due some structural changes, i.e. agglomeration of Au nanoparticles on the surface of composite. (C) 2015 Elsevier B.V. All rights reserved.