Open-cell bipolar anodization of W and Ti: effect of bipolar electrode position

Abstract

In the present study, we introduce a novel approach for growing anodic layers using bipolar anodization of 2D W and Ti meshes, without a direct electrical connection. These W and Ti meshes were used as a bipolar electrode (BPE) and were wirelessly anodized using an open-cell setup in two different positions - at the bottom of the cell and in the elevated position, centered between the feeder electrodes (FEs). An alternating electric field was applied between two FEs. Remarkably, WO3 nanoporous and TiO2 nanotube layers were successfully formed on the corresponding meshes across their entire surface in both anodization positions. However, oxide layers grown in the bottom position were consistently thicker, due to stronger local electric fields and more effective polarization. This wireless anodization strategy offers a promising and scalable route for the surface functionalization of metal 2D structures by anodization, eliminating the need for direct electrical contacts.