Engineering of highly ordered TiO2 nanopore arrays by anodization

[Display omitted] •Current density distribution in TiO2 barrier layer was simulated.•Current density at the barrier layer surface is morphologically sensitive.•Current density distribution can be adjusted to favor the formation of either tubular structure or porous structure.•Highly ordered anodic TiO2 nanopore arrays similar to AAO were prepared. Finite element analysis was used to simulate the current density distributions in the TiO2 barrier layer formed at the initial stage of Ti anodization. The morphology modification of the barrier layer was found to induce current density distribution change. By starting the anodization with proper TiO2 barrier layer morphology, the current density distribution can be adjusted to favor the formation of either nanotube arrays or nanopore arrays of anodic TiO2. We also found that the addition of sodium acetate into the electrolyte suppressed both the field-assisted chemical dissolution of TiO2 and the TiF62− hydrolysis induced TiO2 deposition during anodization, and thus further favored the nanopore formation. Accordingly, highly ordered anodic TiO2 nanopore arrays, similar to anodic aluminum oxide nanopore arrays, were successfully prepared.