Synthesis of Rare-Earth-Based Metallic Electride Nanoparticles and Their Catalytic Applications to Selective Hydrogenation and Ammonia Synthesis

We report the successful synthesis of La-Cu0.67Si1.33 and Y5Si3 electride nanoparticles (NPs) using the Ar/H-2 arc evaporation technique. The obtained particle sizes are 10-50 nm in diameter, and their surface areas are enhanced by orders of magnitude compared with hand-milled samples. Their catalytic performances were indeed improved by a factor of 60 for the hydrogenation of nitrobenzene (LaCu0.67Si1.33) and 3 for ammonia synthesis (Ru-loaded Y5Si3). This marked difference in the enhancement of catalytic activities between each system can be attributed to the geometric structure of active sites. These results show that the Ar/H-2 arc evaporation technique offers wide versatility for the preparation of rare-earth-based electride NPs with enhanced catalytic activities.