Enhanced Ammonia Synthesis Performance over Ru-Based Catalysts via the Addition of Ce Promoter

The development of advanced catalysts is critical to realize efficient ammonia (NH 3 ) synthesis under mild conditions. However, the activation of an inert N≡N bond in N 2 molecules is the primary hindrance to NH 3 synthesis, and hydrogen poisoning is another major and a serious problem, especially in Ru-based catalysts. Here, we develop an H-ZSM-5-supported Ru-based catalyst (Ce–Ru/HZ) via decorating with a CeO 2 promoter to realize efficient NH 3 synthesis. Our study shows that the Ce species can serve as an electron donor to enrich the electron density of Ru sites, thus accelerating N 2 activation for NH 3 synthesis. Meanwhile, the interaction of Ru and Ce can alleviate the effect of hydrogen poisoning on Ru sites. Consequently, the 16 wt % Ce-promoted Ru/HZ catalyst displays a superior NH 3 synthesis rate and long-term stability of more than 550 h at 400 °C and 1 MPa.