Synthesis of ZrO2 nanotubes in inorganic and organic electrolytes by anodic oxidation of zirconium

Present work reports on the results of the electrochemical growth of self-ordered zirconia nanotubes formed in aqueous Na₂SO₄?+?HF and nonaqueous electrolytes with glycerol addition. Anodization process was carried out in this inorganic water-based mixture with constant pH?=?2.5 and in the voltage range from 5 to 60 V. Similar experiments were repeated in an organic glycerol-based electrolyte with the voltage equal to 20 V and with variable glycerol concentration. All experiments were conducted at constant room temperature. The tube diameter dependence on the voltage of anodization process in an inorganic electrolyte was derived. It was found that when glycerol addition to water electrolyte was used, it takes more time to produce long zirconia nanotubes. However, they do not collapse as the similar structure of the same length formed in aqueous electrolyte.