Formation of ZnO nanowires by anodization under hydrodynamic conditions for photoelectrochemical water splitting

The present work studies the influence of hydrodynamic conditions (from 0 to 5000 rpm) during Zn anodization process on the morphology, structure and photoelectrocatalytic behavior of ZnO nanostructures. For this purpose, analysis with Confocal Laser-Raman Spectroscopy, Field Emission Scanning Electron Microscope (FE-SEM) and photoelectrochemical water splitting tests were performed. This investigation reveals that hydrodynamic conditions during anodization promoted the formation of ordered ZnO nanowires along the surface that greatly enhance its stability and increases the photocurrent density response for water splitting in a 159% at the 5000 rpm electrode rotation speed. •ZnO nanowires were obtained by anodization of Zn in bicarbonate electrolyte.•Anodization was performed under controlled hydrodynamic conditions.•Dynamic conditions during anodization enhanced the formation of ordered nanowires.•Low dark current densities were achieved by anodization over 3000 rpm rotation speeds.•ZnO nanostructures showed high photocurrent density during water splitting test.