Photochargeable Behaviors of Hydrogen Storage Alloy's Electrode Modified with Nano-TiO2 Photocatalyst

Nanocrystalline anatase-type TiO2 was prepared by the hydrolysis-precipitaiton method, the rare earth hydrogen storage alloys were modified with the as-prepared TiO2 and the photocharging behavior, and cyclic voltammetry curves and EIS spectra were measured. The experimental results show that the potential has little shift under the light irradiation for the unmodified electrode. However, for the TiO2modified electrode, a remarkable shift of the potential to negative direction (up to -0.835 V) takes place under the light irradiation, which means the generation of H atom on the electrode surface under the light irradiation. The EIS results also indicate that there exists the absorption of H atom and the following diffusion of H atom into the hydrogen storage alloys under the light irradiation. The FEM observations on the electrode surface show that a large amount of microcracks appear on the electrode surface. These microcracks may be induced by the bulk expansion when the generated hydrogen atoms were absorbed by the hydrogen storage alloys.