Preparation and characterization of hollow glass microspheres (HGMs) for hydrogen storage using urea as a blowing agent

Abstract

Hollow glass microspheres (HGMs) are unique class of porous material that can be used for hydrogen storage. They are finely dispersed and free flowing powder having microsphere diameter, 10–200μm and wall thickness, 0.5–2μm. In this report, we present the preparation of HGMs from glass frits using air-acetylene flame spheroidisation method. Urea was incorporated in the feed glass as a blowing agent to get porous walled HGMs. Effect of concentration of urea in the feed glass on the development of pores on HGMs wall was investigated. It was observed that, the porosity of the HGMS walls increased with the increase in urea content in the feed glass. Characterization of HGMs prepared was done using FE–SEM, ESEM, FTIR and XRD techniques. The spherical nature and the morphology of the HGMs samples prepared were confirmed using FE–SEM, while the pore diameter and the porosity of the samples was observed in the ESEM images. Hydrogen adsorption experiments were carried out at room temperature (RT) and 200°C at 10bar pressure, for 5h for all the HGMs samples prepared. The HGMs prepared with 2% urea showed large number of micro/nano pores and it showed a hydrogen storage capacity of 2.3wt.% at 200°C and 10bar pressure. The hydrogen adsorption on HGMs at RT and 10bar pressure was lower than that observed at 200°C and 10bar pressure.