Nanomaterials From Imogolite: Structure, Properties, and Functional Materials

International audienceHollow cylinders with a diameter in the nanometer range are carving out prime positions in nanoscience. Thanks to their physico-chemical properties, they could be key elements for next-generation nanofluidics devices, for selective molecular sieving, energy conversion or as catalytic nanoreactors. Several difficult problems such as fine diameter and interface control are solved for imogolite nanotubes. This chapter will present an overview of this unique class of clay nanotubes, from their geological occurrence to their synthesis and their applications. In particular, emphasis will be put on providing an up-to-date description of their structure and properties, their synthesis and the strategies developed to modify their interfaces in a controlled manner. Developments on their applications, in particular for polymer/imogolite nanotubes composites, molecular confinement or catalysis, are presented

Enhancement of electrochemical activity of Raney-type NiZn coatings by modifying with PtRu binary deposits: Application for alkaline water electrolysis

This study presents electrochemical preparation and characterization of PtRu-modified Cu/Ni/NiZn electrodes (Cu/Ni/NiZn-PtRu) as cathode materials for alkaline water electrolysis. The electrodes were characterized using energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Their electrochemical activities as cathode materials for alkaline water electrolysis were evaluated with the help of current potential curves. The results showed that the PtRu-modified layers have porous structures with relatively low Pt and Ru chemical compositions. The modification of the alkaline leached Cu/Ni/NiZn surface by Pt and/or Ru enhances the electrochemical activity of the electrode. Their catalytic activity depends on the molar ratios of Pt and Ru; the PtRu binary deposit with the percentage weight ratio of approximately 56:44 exhibits the highest hydrogen evolution activity among the studied electrodes. The enhanced hydrogen evolution activity of the PtRu-modified electrodes was related to the porous surface and/or a possible synergistic effect between the metals. Copyright (c) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved