Abstract
Ammonia is one of the best potential hydrogen storage materials, having a high volumetric (121 kg H-2/m(3)) and gravimetric (17.75 wt%) hydrogen capacity. Its properties fully correspond to the DOE's (Department of Environment, USA) hydrogen storage requirements as a commercial hydrogen storage material. Ammonia can be used for onboard clean (COX free) hydrogen generation (2NH(3) double left right arrow N-2 + 3H(2)) for fuel cell-driven vehicles. The main challenge of using ammonia to produce clean hydrogen via an onboard catalytic decomposition process necessitates a catalyst able to decompose 100% ammonia at a low temperature (>= 400 degrees C) and supply pure hydrogen to the fuel cell. Currently, only ruthenium-based catalysts showed activity to complete decomposition of ammonia at 400 degrees C and above but the scarcity of precious ruthenium put an economic constraint in the wide application of ruthenium-based catalysts and drive researchers to look for alternative (non-precious) catalytic materials for this reaction. This chapter describes briefly about hydrogen and current hydrogen production and storage technologies, the cost of hydrogen production from different processes, ammonia and current status of ammonia production followed by a detailed discussion of different ammonia decomposition catalysts.