Cation doped cerium oxynitride with anion vacancies for Fe-based catalyst with improved activity and oxygenate tolerance for efficient synthesis of ammonia

For the first time, new Sm doped cerium oxynitrides with formula Ce1-zSmzO2-xNy (z ? 0.5) are synthesized in order to maximize concentration of anion vacancies. Single phase Sm-doped CeO2-xNy were confirmed by XRD, HRTEM and Rietveld refinement. These show a great promotion effect for low-cost Fe catalyst ammonia synthesis. At 350 °C 1 MPa, activity 80 wt% Fe- 20 Ce1-zSmzO2xNy is one highest reported non-Ru catalysts Haber-Bosch reaction. The apparent activation energy z ? 0.3 around 45 kJ/mol, which lowest range among all synthesis catalysts. Introduction nitrogen vacancies through doping may facilitate mobility This study demonstrates large vacancies, particularly excellent promoters/co-catalysts