HYDROGEN ABSORPTION IN VANADIUM PENTOXIDE

This paper describes the reactor developed in the authors' laboratory for studying the hydrogen absorption characteristics of materials suitable for hydrogen energy storage and H//2-D//2 separation. Vanadium pentoxide has been chosen for the case study. It is found that platinum-activated V//2O//5 reacts with hydrogen at around 150 degree C to give H//3V//2O//5. The hydrogen insertion creates distortion in the orthorhombic structure of V//2O//5 and decreases the crystal symmetry by forming a monoclinic phase of composition H//6V//4O//1//0. On heating the hydride phase at 426 degree C in air, V//2O//5 can be recovered as finer (compared to the starting material) powder. The enthalpy of hydride formation is estimated as 12. 15 kcal/mol H//2, the plateau pressure being 2. 2 atm.