Reconstruction of SnO2 after cathodic polarization of FTO films - A simple way of fabricating orthorhombic SnO2

Fluorine doped tin oxide layers (F:SnO2, "FTO") on glass were electrochemically reduced and the resulting layers of tin were re-oxidized. By electrochemical re-oxidation, tetragonal SnO2 was obtained, whereas thermal oxidation led to orthorhombic SnO2. The reconstructed SnO2 was resistive and showed an increase of roughness and porosity compared to the initial smooth and dense FTO. The double layer capacity indicated an increase in the electrochemically active surface area.