Electrodeposition of TiO2 Nanoparticles on Multiwalled Carbon Nanotube Arrays for Hydrogen Peroxide Sensing

In this work, an amperometric H2O2 sensor based on TiO2/MWCNTs electrode is reported. TiO2 nanoparticles were synthesized on vertically aligned multiwalled carbon nanotube (MWCNT) arrays by electrodeposition. The morphology of the TiO2/MWCNTs was characterized by scanning electron microscopy (SEM). The electrochemical performance of the TiO2/MWCNTs electrode for detection of H2O2 was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry. The TiO2/MWCNTs electrode displays high electrocatalytic activity towards oxidation of H2O2 in 0.1 M phosphate buffer solution (PBS, pH 7.4). At an applied potential of +0.40 V, the TiO2/MWCNTs electrode exhibits a linear dependence (R=0.998) in the H2O2 concentration up to 15.0×10−3 M with a sensitivity of 13.4 μA mM−1 and detection limit of 4.0×10−7 M with signal/noise=3. The optimal response time is less than 5 s with addition of 1 mM H2O2. The TiO2/MWCNTs electrode presents stable, high sensitivity and also exhibits fast amperometric response to the detection of H2O2, which is promising for the development of H2O2 sensor.