Chemical polishing of titanium foil and detachment of TiO₂nanotubes as key synthesis parameters to gas sensing applications

In this work, we present two key parameters, chemical polishing and detachment, to improve the synthesis and organization of TiO2 nanotubes for gas sensing applications. Chemical polishing with an acid solution was applied to a titanium foil to reduce its roughness before synthesis. Next, TiO2 nanotubes were synthesized through a three-step anodization process, after the first and second steps, the detachment process was performed using two chemical solutions: one for partial detachment and one for complete detachment. The effect of these parameters was studied by FE-SEM and AFM. We found a significant decrease in roughness because the chemical polishing decreases the irregularities of titanium foil. Furthermore, the complete detachment improves the organization of nanotubes, like a honeycomb, because Ti nanobowls operate as a template. The TiO2 nanotubes were subjected to gas sensing tests, which showed that a better organization of nanotubes leads to an increase in the change of electrical resistance for reducing gas.