Effect of duty cycle and electrolyte additive on photocatalytic performance of TiO2-ZrO2 composite layers prepared on CP Ti by micro arc oxidation method

•TiO2-ZrO2 composite layers are formed by micro arc oxidation (MAO).•The microdischarge regime is influenced by duty cycle.•Zr4 + ions replace Ti4 + ions and form impurity levels, which could prolong carrier lifetime.•The synthesized composite layers show enhanced photo-catalytic activity.•Photocatalytic activity of layers is related to morphology and elemental composition.

The aim of this work is to discuss the photocatalytic performance of the titania-zirconia porous photocatalyst layers synthesized via micro arc oxidation technique. An attempt was also made to put forward the basic formation mechanism of the layers. Impedance and optical properties of the photocatalyst layers were studied by electrochemical impedance spectroscopy (EIS), Photoluminescence spectroscopy and UV-vis absorption spectroscopy, in order to assess their intrinsic catalytic properties. The results of the EIS were correlated with the microstructural characteristics along with measurements of Methylene Blue (MB) photocatalytic degradation. The results show enhanced photocatalytic activity of TiO2-ZrO2 composite layers compared to pure TiO2 layer. It was revealed that the photocatalytic activity of the layers prepared at different duty cycles is influenced by characteristics of microdischarge regime imposed by working electrolytes with varying additive concentration. The results of photocatalytic degradation of methylene blue were in good agreement with those obtained from electrochemical analysis.