Effects of electrolyte composition on the growth and properties of titanium oxide nanotubes

•The anodizing mechanism and results of two different electrolytes.•Influence of sodium salt on anodization in two different electrolytes.•Systematic explanation of more changes in various aspects of nanotubes.•The interesting results explained by oxygen bubble model and double current theory. Titanium oxide nanotubes prepared by anodization are widely used in many fields due to their excellent properties, but the formation mechanism is still under discussion. This paper focuses on the formation of TiO2 nanotubes in different electrolytes. We explored the influence of electrolyte components on anodization process and results through analysing the current–time curves and SEM images. The results showed that the addition of ionizable sodium salt to the electrolyte increased the conductivity of electrolytes, and then promoted the growth of nanotubes with improving the properties. In this paper, we explained the interesting experimental results by the oxygen bubble model theory and double current(ionic current and electronic current) theory.