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 (NH3) synthesis under mild conditions. However, the activation of an inert N≡N bond in N2 molecules is the primary hindrance to NH3 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 CeO2 promoter to realize efficient NH3 synthesis. Our study shows that the Ce species can serve as an electron donor to enrich the electron density of Ru sites, thus accelerating N2 activation for NH3 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 NH3 synthesis rate and long-term stability of more than 550 h at 400 °C and 1 MPa.