Pure Siliceous Zeolite-Supported Ru Single-Atom Active Sites for Ammonia Synthesis

Abstract

As the most active new frontier, a single-atom catalyst (SAC) combining the merits of heterogeneous and homogeneous catalysts would have a significant effect on the 100 year history of ammonia synthesis research. Here, the Ru SAC has been demonstrated to be active and efficient for ammonia synthesis. To this end, an ideal model catalyst, pure siliceous zeolite-supported Ru SAC (Ru SAs/S-1), which shows surprising catalytic ammonia synthesis activity compared to that of a conventional Ru catalyst, was designed. Both atomic-resolution scanning transmission electron microscopy, X-ray absorption spectrometric analysis, and in situ diffuse reflectance infrared Fourier transform spectroscopy identify the single-Ru-atom nature of Ru SAs/S-1 before and after the reaction. Further DFT calculations reveal that the reaction mechanism is different from traditional mechanisms. Therefore, this paper provides an alternative SAC strategy to design high-performance Ru catalysts for ammonia synthesis.