Ru alloying with La or Y for ammonia synthesis via integrated dissociative and associative mechanism with superior operational stability

The alloying of Ru with rare-earth elements (REEs) is an effective approach for the modification of the electronic structure of Ru. Here, for the first time, we report the formation of Ru-M (M = La or Y) alloys that are endowed with a completely new type of active sites. Over the Ru-M (M = La or Y) catalysts, N₂ activation in ammonia synthesis follows neither the well-known dissociative nor the associative route but rather a co-operation of both, leading to outstanding performance. The developed RuLa/HZ catalyst exhibits a NH₃ synthesis rate of 14.73 mmol g_cat⁻¹ h⁻¹ at 400 °C and 1 MPa without obvious deactivation in a run of 1756 h (ca.73 days).