Science Tokyo cobalt catalyst on antiperovskite makes ammonia at 300 °C and 0.9 MPa, 15.9 mmol/g/h

Researchers at the MDX Research Center for Element Strategy, Institute of Science Tokyo, led by Yihao Jiang, Hideo Hosono and Masaaki Kitano, developed a cobalt catalyst on an antiperovskite support for ammonia synthesis. The work was published in the Journal of the American Chemical Society on October 28, 2026. According to the authors, the optimized catalyst produces ammonia at 15.9 mmol g–1 h–1 at 0.9 MPa and 300 °C doi.orgJournal of the American Chemical Societydoi.orgOpen source ↗.

Material and structure

The support is Ba3AlO4-xNyHz, a metastable compound with an antiperovskite structure. It is stabilized by combining several anions with different valences and ionic radii: oxide, nitride, hydride and molecular dinitrogen anions (N2)− doi.orgJournal of the American Chemical Societydoi.orgOpen source ↗. Barium-based compounds such as barium subnitride (Ba2N) activate nitrogen well, but they are unstable in hydrogen and degrade during synthesis, according to the release.

The team grew Ba3AlO4-xNyHz as a thin shell on γ-Al2O3 nanorods. Cobalt, 5.8 wt % in the optimized sample, self-organized on this shell, so the support and the metal formed a hierarchically structured catalyst doi.orgJournal of the American Chemical Societydoi.orgOpen source ↗. The catalyst contains no noble metals.

Activity and mechanism

The Co(5.8 wt %)/Ba3AlO4-xNyHz/Al2O3 catalyst outperformed the benchmark Cs–Ru/MgO, an industrial iron catalyst and recently reported non-noble metal catalysts, the authors report doi.orgJournal of the American Chemical Societydoi.orgOpen source ↗.

To identify the mechanism, the researchers combined experiments with density functional theory calculations; the release also mentions isotope labeling and spectroscopy. They conclude that the activity originates from (N2)− ions at Co–Ba–Al interfacial sites doi.orgJournal of the American Chemical Societydoi.orgOpen source ↗. Barium and aluminum play distinct roles there: barium is involved in N2 activation, and aluminum in the formation of NHx species doi.orgJournal of the American Chemical Societydoi.orgOpen source ↗. Per the release, barium sites weaken the nitrogen–nitrogen bond, which allows (N2)− to dissociate and to be replenished quickly with N2, while cobalt and aluminum sites assist the later steps leading to NH3.

Ammonia is used mainly in fertilizer production and is considered a carbon-free hydrogen carrier. Its synthesis still relies on high temperatures and pressures because of the strong bond between nitrogen atoms in N2. The authors say the work offers a way to stabilize metastable crystal structures by incorporating diverse anions doi.orgJournal of the American Chemical Societydoi.orgOpen source ↗.