Ammonia decomposition catalysis using lithium–calcium imide

Lithium–calcium imide is explored as a catalyst for the decomposition of ammonia. It shows the highest ammonia decomposition activity yet reported for a pure light metal amide or imide, comparable to lithium imide–amide at high temperature, with superior conversion observed at lower temperatures. Importantly, the post-reaction mass recovery of lithium–calcium imide is almost complete, indicating that it may be easier to contain than the other amide–imide catalysts reported to date. The basis of this improved recovery is that the catalyst is, at least partially, solid across the temperature range studied under ammonia flow. However, lithium–calcium imide itself is only stable at low and high temperatures under ammonia, with in situ powder diffraction showing the decomposition of the catalyst to lithium amide–imide and calcium imide at intermediate temperatures of 200–460 °C.