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

Abstract

a b s t r a c tIrradiated by heavy ions nanoporous polyethylene terephthalate track-etched membranes (PET TeMs) after +15 Kr 84 ions bombardment (1.75 MeV/nucl with the ion fluency of 1 Â 10 9 cm À2 ) 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°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 À91.44 kJ/mol due some structural changes, i.e. agglomeration of Au nanoparticles on the surface of composite.

Temperature Dependent Catalytic Activity of Ag/PET Ion-Track Membranes Composites

“…As shown in the Table in the case of applying Ag/PET composite membranes for reduction of 4-NP, the constant rate slowly decreases, the composite surface does not damage during this reaction [22]. For decomposition of hydrogen peroxide reaction, the reaction rate of the second cycle is decreased 2.4 times as well as second reuse reduce conversion of H 2 O 2 to 54.7% suggesting removal of active Ag with the smallest diameter from the surface of the composite membrane since reaction is carried out under vigorous release of oxygen during the first cycle of testing.…”

A Review on Catalytic Membranes Production and Applications

“…All tested membranes exhibited quite a good stability and the activity of catalytic membrane had no any significant decrease after reuse at least 5 cycles [41].…”

“…Mashentseva et al [41] described the effect of deposition of Au-and Ag-based nanotubes on the polyethylene terephthalate track-etched membranes [41]. The PET film was irradiated with Kr ions and etched in sodium hydroxide solution 2.2 M at 85 o C for 75 s to provide formation of cylindrical pores in size of the 100±5 nm and the deposition of Au and Ag nanotubes were carried out by low electrodeposition technique.…”

“…The PET film was irradiated with Kr ions and etched in sodium hydroxide solution 2.2 M at 85 o C for 75 s to provide formation of cylindrical pores in size of the 100±5 nm and the deposition of Au and Ag nanotubes were carried out by low electrodeposition technique. In recent days, the embedded of noble gold and silver nanotubes (NTs) in porous membranes are an important trend of functional composites to their unique properties and potential application in sensors [42] or electrochemical electrodes [43], heterogeneous catalysts [44] and in flow through reactors, also in medicine [41,45].…”

“…Mashentseva et al [41] used the single step catalytic hydrogenation of P-nitrophenol (4-NP) to P-aminophenol (4-AP) by reducing agent sodium borohydride in aqueous solution to test the catalytic membrane activity. All tested membranes exhibited quite a good stability and the activity of catalytic membrane had no any significant decrease after reuse at least 5 cycles [41].…”