Interaction Between Ru Nanoparticles and Pr₆O₁₁ Triggers Catalytic Ammonia Synthesis

The essential role of metal–support interaction in ammonia synthesis was investigated by using a Pr₆O₁₁ supported Ru nanoparticles (NPs) catalyst system. Loading of Ru NPs onto the Pr₆O₁₁ support with relatively low surface area yields similar metal dispersion with respect to conventional SiO₂ support. The Ru NPs on the Pr₆O₁₁ was found to exhibit excellent catalytic performance in ammonia synthesis, superior to free-standing Ru NPs and Ru NPs on conventional SiO₂ support. Detailed structure analysis results reveal that the superior activity of Ru/Pr₆O₁₁ can be attributed to the enhanced interaction between the Ru NPs and Pr₆O₁₁, which can modulate the electronic structure of Ru NPs and trigger catalytic ammonia synthesis over Ru NPs on Pr₆O₁₁. Furthermore, nitrogen isotope exchange experiment reveals that superior nitrogen dissociation ability is essential for the excellent activity and intrinsic activity of Ru/Pr₆O₁₁ in ammonia synthesis. These findings demonstrate that Pr₆O₁₁ can be used as a new kind of support for preparation of efficient Ru-based catalysts for ammonia synthesis, and also open up opportunities for design of Pr₆O₁₁ supported metal catalysts for other catalytic reactions.

Interaction between the Ru NPs and Pr₆O₁₁ can modulate the electronic structure of Ru NPs and trigger catalytic ammonia synthesis over Ru NPs on Pr₆O₁₁.