摘要

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 H2O2. Thus, the hemin-TiO2 modified electrode was employed as an electrochemical sensor for H2O2 determination, showing a sensitive response linearly proportional to the concentration of H2O2 from 3.0 x 10(-7) to 4.7 x 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 x 10(-7) to 3.0 x 10(-5) mol.L-1.