Hemin Modified TiO 2 Nanoparticles with Enhanced Photoelectrocatalytic Activity for Electrochemical and Photoelectrochemical Sensing

Abstract

© The Author(s) 2016. Published by ECS. Hemin-functionalized TiO2 nanoparticles were prepared and assembled on glassy carbon electrode through the electrostatic attraction between positively charged poly(diallyldimethylammonium chloride) and negatively charged hemin and TiO2 . The scanning electron microscopy and X-ray diffraction characterization showed that the assembled hemin-TiO2 film displayed a mesoporous structure comprising plenty of TiO2 nanoparticles in rutile phase. The Fourier transform infrared spectra and UV-visible diffuse reflectance spectra indicated that hemin was successfully incorporated into TiO2 film and significantly enhanced the absorption of TiO2 film to visible light. The hemin-TiO2 film exhibited a pair of well-defined redox peaks of hemin by cyclic voltammetry, which could effectively catalyze the electroreduction of H2 O2 . Thus, the hemin-TiO2 modified electrode was employed as an electrochemical sensor for H2 O2 determination, showing a sensitive response linearly proportional to the concentration of H2 O2 from 3.0 ? 10-7 to 4.7 ? 10-4 mol • L-1 . At the same time, the photoelectrocatalytic activity of TiO2 under visible light illumination was dramatically promoted by hemin. The hemin-TiO2 modified electrode produced a photoelectrochemical response linearly proportional to hydroquinone in the concentration range from 4.0 χ 10-7 to 3.0 χ 10-5 mol • L-1 .