Mesoporous-TiO2 nanoparticles based carbon paste electrodes exhibit enhanced electrochemical sensitivity for phenols

Mesoporous-TiO2 nanoparticles (meso-TiO2) and nano-TiO2 particles (nano-TiO2) were synthesized and characterized using scanning electron microscopy. The electrochemical behaviours of carbon paste electrodes (CPE), nano-TiO2/CPE and meso-TiO2/CPE were investigated using K-3[Fe(CN)(6)] as the electrochemical probe. It was observed that the peak potential separation was remarkably decreased at the meso-TiO2/CPE with higher peak currents in comparison with the other two CPEs. Moreover, the electrochemical performance towards phenol and p-substituted phenol detection was studied with remarkably enhanced oxidation signals at meso-TiO2/CPE. The meso-TiO2 shows considerable surface enhancement effects towards phenols which increase linearly with Hammett's constants. Additionally at higher NaCl concentrations, the oxidation peak currents of phenols notably increases at meso-TiO2/CPE, while remaining unchanged at CPE and nano-TiO2/CPE. In summary meso-TiO2 nanoparticles are superior electrode materials for electrocatalysis. (C) 2009 Elsevier B.V. All rights reserved.