An efficient thin-walled Pd/polypyrrole hybrid nanotube biocatalyst for sensitive detection of ascorbic acid.

Controllable fabrication of novel and uniform noble metal nanoparticles on a specific support with a superior catalytic or electrocatalytic performance is of significantly importance for practical applications. In this report, we demonstrated an effective way to fabricate uniform thin-walled Pd/polypyrrole (PPy) hollow nanotubes. The prepared Pd/PPy hybrid nanotubes exhibited an excellent peroxidase-like activity to oxidize a typical peroxidase substrate such as 3,3',5,5'-tetramethylbenzidine in comparison with traditional Pd/C and Pd black catalysts. The outstanding catalytic activity of the Pd/PPy hybrid nanotubes for peroxidase mimicking could be resulting from their unique hollow characteristic and an interfacial effect between PPy and Pd components. Based on the favorable catalytic property of the Pd/PPy hybrid nanotubes, a convenient and rapid colorimetric way to sensitively determine ascorbic acid has been presented. The detection limit was around 0.062 μM and an excellent selectivity was also achieved. The developed detection system in this study could be extended to the fields of bioscience and biotechnology with promising prospects.