Immobilization of laccase onto 1-aminopyrene functionalized carbon nanotubes and their electrocatalytic activity for oxygen reduction

Abstract

Carbon nanotubes (CNTs) were non-covalent-functionalized with 1-aminopyrene (1-AP) and used for the first time to immobilize laccase (Lac) with the aid of glutaraldehyde (GA). The results of Fourier transform infrared (FTIR) spectra confirmed the successful modification of CNTs with 1-AP. The dispersibility of CNTs in aqueous solution was improved by the functionalization of 1-AP. The electrocatalytic properties of the Lac immobilized on the 1-AP functionalized CNTs (Lac/AP–CNTs) for oxygen reduction have been investigated by cyclic voltammetry in the presence of 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonate) diammonium salt (ABTS) in the Britton–Robinson (B–R) buffer solution (pH 3.0). Under the same experimental condition, the Lac/AP–CNTs catalyst shows higher electrocatalytic activity and better stability than the Lac immobilized on the pristine CNTs (Lac/CNTs). Additionally, effects of the mass ratio of 1-AP to CNTs in the AP–CNTs composites, the loading mass of the Lac/AP–CNTs catalyst and the pH value of the electrolyte on the electrocatalytic activity of the Lac/AP–CNTs/glassy carbon electrode for oxygen reduction were also optimized.