Pseudo catalytic ammonia synthesis by lithium–tin alloy

Abstract

In this work, nitrogenation, ammonia generation, regeneration reactions of lithium-tin alloy is investigated as pseudo catalytic process of ammonia synthesis. Li17Sn4 synthesized by thermochemical method at 500 °C can react with 0.1 MPa of N2 below 400 °C. Nano or amorphous lithium nitride would be formed by the nitrogenation. By reaction of the nitrogenated samples and H2, ammonia is generated at 300 °C under 0.1 MPa. The initial alloy phase Li17Sn4 is regenerated below 350 °C from the products after the ammonia generation process. Based on the above three step process, ammonia can be pseudo-catalytically synthesized from N2 and H2 below 400 °C under ambient pressure. Furthermore, the reactivity for the ammonia synthesis using Li–Sn alloy is preserved during the NH3 synthesis cycles due to the characteristic reaction process based on the Li extraction and insertion.