Anodic growth of hierarchically structured nanotubular ZnO architectures on zinc surfaces using a sulfide based electrolyte

We report on the formation of self-organized nanotubular oxide structures by anodization of zinc in a sulfide based electrolyte. Under optimized experimental conditions, successful growth of a several micrometer long self-organized tubular structure is achieved. The anodized samples were characterized using FE-SEM, XPS, XRD and SAED. The key to formation of tubular ZnO is a protective sulfide containing initial layer. In contrast to other self-ordered tubular geometries, ZnO anodic layers consist of a particular tube wall structure. The resulting double hierarchy layers show a considerable efficiency for photoelectrochemical splitting of water when used in a sacrificial polysulfide electrolyte.