Effect of reaction conditions and surface characteristics of Ru/CeO_2 on catalytic performance for ammonia synthesis as a clean fuel

摘要

The impact of reaction parameters and surface characteristics on NH3 synthesis activity of the Ru/CeO2 catalyst was explored. An exceptionally higher NH3 synthesis activity was observed at 375 degrees C and 2.5 MPa gauge pressure. The H-2/N-2 ratio among the reactants strongly affected the catalytic activity. The catalytic activity enhanced at higher temperatures for a higher H-2/N-2 ratio, while the lower H-2/N-2 ratio was suitable for improved NH3 synthesis at a lower temperature while working at 2.5 MPa gauge pressure. Likewise, NH3 synthesis activity of Ru/CeO2 catalyst enhanced abruptly on increasing pressure at relatively higher temperature conditions, using a reactant flow with a higher H-2/N-2 ratio. The NH3 synthesis activity enhanced with time on stream. This increase in activity was associated with an increase in Ru particles with high dispersion on the surface of the catalyst during NH3 synthesis, confirmed by FIB-TEM and EDS analysis of the cross-sections of catalyst particles. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.