Regulating the interaction of Ru nanoparticles and an Eu2O3 support achieves enhanced activity for ammonia synthesis

Abstract

Development of efficient oxide supported Ru catalysts plays a pivotal role in advancing the ammonia synthesis process. Herein, three Ru/Eu₂O₃ analogues with nearly identical Ru nanoparticles (NPs) on Eu₂O₃ were constructed by dispersing similar RuO₂ NPs on the surface of Eu₂O₃ using solid milling, impregnation and precipitation methods. Among them, the Ru/Eu₂O₃ with a weight loading of 3% from the precipitation method gives much higher activity than the Ru/Eu₂O₃ analogues from the impregnation and solid milling methods. Characterization results reveal that the Ru/Eu₂O₃ obtained via the precipitation method can enhance the interaction between the Ru NPs and Eu₂O₃ support, which can facilitate the activation of nitrogen on the surface of Ru NPs, which is the well-recognized rate determining step during the ammonia synthesis process. Therefore, the Ru NPs in Ru/Eu₂O₃ from the precipitation method show remarkably enhanced intrinsic catalytic activity, superior to many typical efficient Ru-based ammonia synthesis catalysts reported previously. This work demonstrates the potential of Eu₂O₃ as a superior support for Ru-based ammonia synthesis catalysts and offers an opportunity for designing efficient oxide supported Ru catalysts by regulating the metal–support interaction of catalysts.