Synthesis and characterization of carbon nanotubes on clay minerals and its application to a hydrogen peroxide biosensor

In this Study, we demonstrate the synthesis of carbon nanotubes (CNTs) on clay minerals, and the development of biosensors based oil Nafion-CNT/Clay-Au and Nafion-CNT/Clay-Au-Glucose oxidase (GOD) composite films for the detection of hydrogen peroxide (H2O2) and glucose, respectively. The CNTs are synthesized on nickel cation exchanged clay mineral platelets. From field-emission scanning electron microscope images, X-ray diffraction, Fourier transfer infrared and thermogravimetric analysis results, the clay layers are exfoliated and delaminated after the growth of CNTs oil them. The mixed hybrid film of Nafion, CNT/Clay. Au particles and GOD is coated on the glassy carbon (GC) electrode to detect H2O2 or glucose. This film exhibits a detection limit of 5.0 x 10(-5) M for H2O2 with a sensitivity of 280 nA nM(-1). In addition, the amperometric response for glucose containing 2.0 mg mL(-1) GOD in the Nafion-CNT/Clay-Au-GOD modified GC electrode exhibits a sensitivity of 620 nA mM(-1) with a linear range up to 1850 mu M. A higher sensitivity and shorter response time are observed with increasing GOD content in the composite matrix film. Besides, the highest sensitivity of 2032 nA mM(-1) is obtained with the addition of the 10.0 mg mL(-1) GOD in the composite film. Consequently, the CNT/Clay/Nafion medium can probably be a useful electrode for the development of sensors due to its high sensitivity and applicability. (C) 2008 Elsevier B.V. All rights reserved.