Theoretical investigations on Niobium based organometallic system as a potential hydrogen storage system, using Density Functional Theory

摘要

Hydrogen is considered as a promising energy alternative to the diminishing levels of fossil fuels due to its abundance , non-polluting and renewable nature . It is a cost-effective energy source as compared to petroleum fuels. Many hydrogen storage materials such as - doped carbon nanotubes , microporous metal organic frameworks (MMOFs ) , metal organic frameworks (MOFs) , metals and complex hydrides have been developed by many groups (1-2). But all these methods have their own drawbacks such as slow kinetics , poor reversibility , need of a catalyst for dehydrogenation (3), high cost and very low desorption temperatures (4). An ideal hydrogen storage material should possess binding energies greater than the simple Van der Waals interaction and lower than the chemical bonding interactions , with an adsorption energy in the range of 0.3 - 0.4 eV for better adsorption and desorption .Carbon based nanostructures have high hydrogen storage capacity (5) and bind H2 loosely via Van der Waals interaction. In order to overcome this difficulty, a novel concept of affixing a single metal atom to carbon nanostructures was suggested. This gave rise to the use of Organometallic compounds, as an important class of materials for the study of hydrogen storage and its use in fuel cell sector.