Growth of Uranyl Hydroxide Nanowires and Nanotubes by the Electrodeposition Method and Their Transformation to One-Dimensional U3O8 Nanostructures

Actinide nanomaterials have great potential for application in the fabrication of nuclear fuels and spent fuel reprocessing in advanced nuclear energy systems. In this work, we used track-etched nanoporous membranes as hard templates to synthesize uranium-based nanomaterials with new structures by electrodeposition. Through electrochemical behavior investigations and subsequent product characterization, the chemical compositions of the deposition product has been confirmed to be uranyl hydroxide. More importantly, accurate control of the morphologies of the deposition product (i.e., nanowires and nanotubes) could be achieved by carefully adjusting the growth parameters such as deposition time and current density. The preferred morphology of the electrodeposition product was nanowires when a low current density was applied, whereas nanotubes could be formed only when a high current density and a short deposition time were both applied. The formation of nanotubes is attributed to the hydrogen bubbles generated by water electrolysis under the overpotential electroreduction conditions. Additionally, we transformed the main chemical composition of the deposition products from uranyl hydroxide to triuranium octoxide by calcination, and SEM results showed that the morphologies of the nanowires and nanotubes were very well maintained after the calcination. Our work provides a useful protocol for the synthesis of one-dimensional uranium-based nanomaterials.