Preparation of graphene nanoplatelet–titanate nanotube composite and its advantages over the two single components as biosensor immobilization materials

• A composite consisting of graphene nanoplatelets (GNPs) and titanate nanotubes (TNTs) were synthesized.
• The composite was characterized by XRD, TEM, FT-IR and impedance.
• Horseradish peroxidase (HRP) biosensors were developed using the composite, GNPs and TNTs as immobilization material respectively.
• Direct electron transfer of HRP was achieved on the composite biosensor.
• The composite HRP biosensor shows superiority over the other two in electrochemical and analytical performance.

A novel nanocomposite consisting of graphene nanoplatelets (GNPs) and titanate nanotubes (TNTs) have been synthesized successfully utilizing the hydrothermal method. The GNP–TNT composite was characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and electrochemical impedance spectroscopy. The voltammetric characterization of GNP–TNT composite, pure GNPs and pure TNTs modified horseradish peroxidase (HRP) biosensors were conducted to select the most suitable electrode immobilization material for enzyme biosensors. The GNPs was firstly eliminated owing to its extremely high background charging current, distinct electrochemical interference from its surface functional groups and low signal to noise ratio. Next, the direct electron transfer of HRP on electrode and the catalytic current of HRP towards H2O2 was increased around 45% and 72% respectively on GNP–TNT composite modified electrodes compared with those on pure TNTs modified electrodes. GNP–TNT composite modified HRP biosensor also exhibited superiority over pure TNTs modified HRP biosensor in the analytical performance. The precision and stability study provided additional evidence for the feasibility of using GNP–TNT composite as electrode modification material.