Assessing potential supports for lithium amide-imide ammonia decomposition catalysts

Lithium amide-imide is an excellent ammonia decomposition catalyst, but its highly reactive nature makes the application of traditional heterogeneous catalyst methods challenging, including the use of porous supports. In this study, lithium amide-imide was tested for compatibility with various support materials (activated carbon, silicon dioxide, aluminum oxide and magnesium oxide). It was found that most of the supports were unsuitable because of their reactivity with the catalyst, especially under flowing ammonia at decomposition conditions (>400 °C and 1 bar). Magnesium oxide, however, did not react with lithium amide-imide under flowing ammonia. Ammonia decomposition experiments over these catalyst-support mixtures showed that the lithium amide-imide/magnesium oxide system gave the best performance and therefore represents an excellent and usable ammonia decomposition catalyst.