Nanoporous PtAg and PtCu alloys with hollow ligaments for enhanced electrocatalysis and glucose biosensing

Abstract

Nanoporous silver (NPS) and copper (NPC) obtained by dealloying AgAl and CuAl alloys, respectively, were used as both three-dimensional templates and reducing agents for the fabrication of nanoporous PtAg (NPS-Pt) and PtCu (NPC-Pt) alloys with hollow ligaments by a simple galvanic replacement reaction with H₂PtCl₆. Electron microscopy and X-ray diffraction characterizations demonstrate that NPS and NPC with similar ligament sizes (30–50 nm) have different effects on the formed hollow nanostructures. For NPS-Pt, the shell of the hollow ligament is seamless. However, the shell of NPC-Pt is comprised of small pores and alloy nanoparticles with a size of ∼3 nm. The as-prepared NPS-Pt and NPC-Pt exhibit remarkably improved electrocatalytic activities towards the oxidation of ethanol and H₂O₂ compared with state-of-the-art Pt/C catalyst, and can be used for sensitive electrochemical sensing applications. The hierarchical nanoporous structure also provides a good microenvironment for enzymes. After immobilization of glucose oxidase (GOx), the enzyme modified nanoporous electrode can sensitively detect glucose in a wide linear range (0.6–20 mM).Nanoporous silver (NPS) and copper (NPC) obtained by dealloying AgAl and CuAl alloys, respectively, were used as both three-dimensional templates and reducing agents for the fabrication of nanoporous PtAg (NPS-Pt) and PtCu (NPC-Pt) alloys with hollow ligaments by a simple galvanic replacement reaction with H(2)PtCl(6). Electron microscopy and X-ray diffraction characterizations demonstrate that NPS and NPC with similar ligament sizes (30-50 nm) have different effects on the formed hollow nanostructures. For NPS-Pt, the shell of the hollow ligament is seamless. However, the shell of NPC-Pt is comprised of small pores and alloy nanoparticles with a size of similar to 3 nm. The as-prepared NPS-Pt and NPC-Pt exhibit remarkably improved electrocatalytic activities towards the oxidation of ethanol and H(2)O(2) compared with state-of-the-art Pt/C catalyst, and can be used for sensitive electrochemical sensing applications. The hierarchical nanoporous structure also provides a good microenvironment for enzymes. After immobilization of glucose oxidase (GOx), the enzyme modified nanoporous electrode can sensitively detect glucose in a wide linear range (0.6-20 mM). (C) 2011 Elsevier B.V. All rights reserved