Improving electrochemical properties of liquid phase deposited TiO2 thin films by doping sodium dodecylsulfonate and its application as bioelectrocatalytic sensor for hydrogen peroxide

Electroactive TiO2 films were prepared by liquid-phase deposition (LPD) in the presence of sodium dodecylsulfonate. The doping of dodecylsulfonate (DS) converted the TiO2 film from a structure of globular nanoparticles to a structure of nano-flakes, which directly influenced the electrochemical behavior of the film. The DS-doped TiO2 film yields an enhanced reduction peak in the cyclic voltammograms, being attributed to the reduction of hydroxylated titanium(IV) species. The varied surface structure of the DS-doped TiO2 film provided a biocompatible platform for immobilizing hemoglobin (Hb), and the Hb-immobilized film electrode exhibited good electrocatalytic activity to the reduction of H2O2. As a sensor for the determination of H2O2, the Hb-immobilized film electrode yielded an excellently linear range from 0.003 to 1.5 mM H2O2 in the correlation between reduction peak current and H2O2 concentration, with a low detection limit of 1.0 μM.