Water Soluble Polymer-SWCNT-Based Composite for Hydrogen Storage

In this study, water soluble polymers such as poly vinyl alcohol (PVA) and poly vinyl pyrrolidone (PVP) were chosen as the base material for hydrogen storage with the aim of producing recyclable and water-soluble polymer-based hydrogen storage material. Initially, the polymers were acid treated using concentrated hydrochloric acid (conc. HCl) to incorporate Cl ions into the polymeric matrices. Furthermore, single-walled carbon nanotubes (SWCNTs) were added to those acid-treated polymers by means of ultrasonication in an aqueous medium as the composite material to increase the hydrogen adsorption. The homogenous composite solution resulted from ultrasonication was then made in the form of film by using the general spin-coating technique. Then, the composite films were hydrogenated in Seiverts' like hydrogenation setup. The preliminary results on hydrogen storage capability of the polymer-SWCNTs composite materials and desorption temperature range of hydrogen are reported. The prepared composite films exhibit good water-soluble properties and recyclability, i.e., they can be formed and dissolved in water. Hydrogen storage in these acid-treated polymer-SWCNTs composite is reported here for the first time. The presence of Cl ions and the adsorption sites offered by SWCNTs were responsible for hydrogen binding in the composite films. The nature of binding of hydrogen in the composite films was found to be weak chemisorption.