A novel Au/r-GO/TNTs electrode for H2O2, O2 and nitrite detection

Au nanoparticles and reduced graphene oxide (r-GO) co-modified TiO2 nanotube arrays (TNTs) were prepared by a facile and green strategy based on the electro-deposition technology for detecting H2O2, O2 and nitrite. As-prepared Au/r-GO/TNTs electrode was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The results clearly demonstrate that the successful attachment of r-GO sheets and narrow-range distribution of Au nanoparticles on TNTs. The reduced grapheme oxide sheet can help to improve the electronic conductive performance of TNTs and prevent the agglomeration of Au nanoparticles. Electrochemical studies reveal that the Au/r-GO/TNTs electrode exhibit excellent electrocatalytic performance toward the reduction of H2O2. Under the optimal experimental condition, the sensor has a quick response to H2O2 at −0.3 V with a high sensitivity (1011.35 mA M−1 cm−2), wide linear range (0.01-22.3 mM) and low detection limit (0.006 μM). In addition, the sensor also has good stability and excellent selectivity. Moreover, the established Au/r-GO/TNTs electrode also shows high sensitivities towards dissolved O2 and nitrite ions, which has great potential for the development of electrochemical sensors, molecular bioelectronics devices and biosensors.