Hydrogen energy in changing environmental scenario: Indian context

摘要

This paper deals with how the Hydrogen Energy may play a crucial role in taking care of the environmental scenario/climate change. The R&D efforts, at the Hydrogen Energy Center, Banaras Hindu University have been described and discussed to elucidate that hydrogen is the best option for taking care of the environmental/climate changes. All three important ingredients for hydrogen economy, i.e., production, storage and application of hydrogen have been dealt with. As regards hydrogen production, solar routes consisting of photo-electrochemical electrolysis of water have been described and discussed. Nanostructured TiO_2 films used as photoanodes have been synthesized through hydrolysis of Ti[OCH(CH_3)_2]_4. Modular designs of TiO_2 photoelectrode-based PEC cells have been fabricated to get high hydrogen production rate (～ 10.35 1h ~1m~(-2)). However, hydrogen storage is a key issue in the success and realization of hydrogen technology and economy. Metal hydrides are the promising candidates due to their safety advantage with high volume efficient storage capacity for on-board applications. As regards storage, we have discussed the storage of hydrogen in intermetallics as well as lightweight complex hydride systems. For intermetallic systems, we have dealt with material tailoring of LaNi_5 through Fe substitution. The La(Ni_(1-x)Fe_x)_5 (x = 0.16) has been found to yield a high storage capacity of ～2.40wt%. We have also discussed how CNT admixing helps to improve the hydrogen desorption rate of NaAlH_4. CNT (8 mol%) admixed NaAlH_4 is found to be optimum for faster desorption (～3.3 wt% H_2 within 2 h). From an applications point of view, we have focused on the use of hydrogen (stored in intermetallic La-Ni-Fe system) as fuel for Internal Combustion (IC) engine-based vehicular transport, particularly two and three-wheelers. It is shown that hydrogen used as a fuel is the most effective alternative fuel for circumventing climate change.