Synergistic photoelectrochemical performance of La-doped RuO₂-TiO₂/Ti electrodes

RuO₂-TiO₂/Ti electrodes with low-content La-doping are prepared by thermal decomposition method. The effect of La doping on their electrochemical performance upon UV illumination are investigated. The doped electrodes show higher density of cracks and rugosity in microscale on the surface than the undoped ones. They also have a negative shift of the onset potential of oxygen evolution from 1.1 V to 1.0 V and higher current intensity under UV irradiation as well. Electrochemical impedence spectroscopy analysis demonstrates a better electrical conductivity of the doped film. Electron paramagnetic resonance results show that the obtained La-doped TiO₂ surface provides a higher density of oxygen vacancies. This anode also has 7.5% higher degradation rate of the methylene blue than La-undoped ones under UV irradiation. This is probably due to the increased surface rugosity and better electric conductivity, higher density of oxygen vacancies under UV irradiation by the doping of La ions.