The Study Of Electrochemical Test On Nano-TiO₂ Film Electrodes

TiO₂ nano-semiconductor film electrodes were prepared by chemical thermal decomposition method, and electrochemical technique was adopted to study the electrodes. The attribution of electrode reactions in 3.5%NaCl aqueous solution, the electrode reaction kinetics, and the band structure of the nano-TiO₂ were explored.Weighing test verifies that the films on the electrodes do not erode or exfoliate in the electrochemical test system. TEM micrograph indicates that the grain size of TiO₂ on the electrodes is controlled at about 20nm.UV-vis spectroscopy was employed to learn the spectral absorption properties of the TiO₂ on the electrodes; it was found that the material has strong absorption in UV region, and still has obvious absorption in visible and near-infrared region.A reference for cyclic voltammetry (CV) was established. In the potential range of -1.8V—0.9697V, there is an oxidation reaction on CV curve which corresponds to the oxidation of trivalent titanium compound to tetravalent titanium oxide. The second oxidation peak on CV curve indicates the generation of hydroxyl radicals (·OH), which were excited by polarization potential, and the minimum polarization potential should meet â–³Eoh-/·oh>+1.453V. CV curve also indicates the generation of superoxide anion radicals. Both the occurrences of hydroxyl radicals and superoxide radicals were verified by electron spin resonance (ESR) test. Looking into the relationship between peak current and the square root of scan speed, it was found that the reaction of trivalent titanium compound to tetravalent titanium oxide and the reaction of ·OH generation are both controlled by diffusion step.By analyzing Mott-Schottky curve, we learned that the flat band potential of the...