Nowadays, the formation mechanism of anodic titanium dioxide nanotubes (ATDNs) is still controversial. Although the field-assisted dissolution reactions are widely cited, more and more experimental facts cannot be explained. In this work, the anodizing processes of Ti in three different electrolytes containing 0.7 wt% NH₄F and 1.8 vol% H₂O are carefully compared. Although the anodizing current–time curves obtained in ethanol electrolyte are similar to those of ethylene glycol, ATDNs are obtained in ethylene glycol but dense TiO₂ films are obtained in ethanol. This interesting result contradicts the field-assisted dissolution reactions of fluoride ions. Based on the oxygen bubble mould and the ionic current and electronic current model, a reasonable interpretation for this result is presented. The low conductivity of the ethanol electrolyte results in small ionic current, which leads to slow growth of the oxide, so the embryos of nanotubes cannot be formed around the oxygen bubbles. In addition, the rises in the current–time curves of ethanol electrolyte are due to the generation of electronic current which leads oxygen bubbles to release from the surface of anodic films directly. This important conclusion is confirmed by ATDNs obtained in the mixture of ethanol and ethylene glycol electrolyte containing the same concentration of fluoride ions.

如今，阳极二氧化钛纳米管（ATDNs）的形成机理仍存在争议。尽管广泛引用了现场辅助的溶解反应，但无法解释越来越多的实验事实。在这项工作中，仔细比较了在三种含0.7 wt％NH ₄ F和1.8 vol％H ₂ O的电解液中Ti的阳极氧化工艺。尽管在乙醇电解质中获得的阳极氧化电流-时间曲线与乙二醇相似，但ATDNs在乙二醇中获得，但TiO ₂致密膜在乙醇中获得。这个有趣的结果与氟离子在现场辅助的溶解反应相矛盾。基于氧气气泡模型，离子电流和电子电流模型，给出了对该结果的合理解释。乙醇电解质的低电导率导致较小的离子电流，这导致氧化物的缓慢生长，因此无法在氧气气泡周围形成纳米管的胚。此外，乙醇电解质电流-时间曲线的上升是由于产生了电子电流，该电流导致氧气气泡直接从阳极膜表面释放。乙醇和乙二醇电解质混合物中含有相同浓度的氟离子可得到ATDN，从而证实了这一重要结论。