Executive Summary : | Designing of materials for hydrogen storage is necessary for hydrogen economy to be a reality otherwise hydrogen economy will be difficult to achieve. US department of energy has set some targets for the hydrogen storage material such as high hydrogen storage capacity of a material (5.5 wt % by 2025), faster adsorption-desorption kinetics at ambient conditions, H? desorption at moderate temperature, operating temperature and pressure etc. Density functional theory (DFT) helps in designing materials without synthesizing a material. Metal doped nanomaterials are found to be promising materials for hydrogen storage. However, metal clustering affects and reduces the hydrogen storage capacity of a material. In this proposal we are going to use density functional theory to design and study H? uptake capacity of metal doped nanocages. Various nanocages viz. C, CN, BN, AlN, SiC and ZnO etc. will be considered for the study. Metal atoms considered for doping will be alkali metals, alkaline earth metals and early transition metals. We will also focus on i) avoiding metal clustering by heteroatom substitution in nanocages to improve the H? uptake and ii) improving H? uptake capacity by controlling the charge on nanocages. Different properties of a material will be forecasted using DFT. Stability of a material will be confirmed by obtaining formation energy and cohesive energy. The H? uptake capacity obtained using DFT will be confirmed using molecular dynamics simulations. Temperature and pressure range over which H2 adsorption on these functional nanomaterials is thermodynamically favourable, H? desorption temperature and desorption energies will also be obtained so that the material can be used in different environment and applications. If the designed materials satisfy the targets set by US DOE, then it can be synthesized for testing and practical applications. Through this proposal, we would be able to suggest metal doped nanocages for hydrogen storage. Findings from the work should give useful guideline to the experimentalist to synthesize the functional nanocages for hydrogen storage. |