Our group recently discovered a Ba-Cr nitride hydride catalyst which realized the catalytic synthesis of ammonia under relatively mild conditions, in cooperation with Prof. Weidenthaler from Max Planck Institute and Prof. Anan Wu from Xiamen University. This work, entitled "Barium Chromium Nitride-hydride for Ammonia Synthesis", was published in Chem Catalysis and was selected as the cover article.
Ammonia is a key ingredient for manufacturing fertilizers and N-containing chemicals. And it is also considered as a promising energy carrier recently. Current NH3 production is dominated by the well-developed Haber–Bosch process operated under harsh conditions with high energy consumption and CO2 emissions. The development of more active catalysts under mild conditions is of important scientific significance and practical value.
In this work, our group a fundamentally new strategy to activate Cr by creating a quaternary barium chromium nitride-hydride structure, which comprises [CrN4] tetrahedral units and [HBa6] octahedral units. The nitride-hydride structure contains hydridic hydrogen (H‾), which function as electron and proton carrier and facilitate electron transfer to N2 and the successive N-H bond formation. The formation of a barium chromium nitride-hydride structure makes a great change, resulting in an activity enhancement by more than 3 orders of magnitude compared to the Cr nitride. The barium chromium nitride-hydride structure comprising of reactive hydrogen (H‾) and nitrogen species creates a chemical environment favorable for N2 activation and hydrogenation under mild conditions. This work discloses a strategy to ‘activate’ the inert early transition metals for effective ammonia catalysis.
This work was supported by the National Natural Science Foundation of China and youth Innovation Promotion Association of The Chinese Academy of Sciences. (Text: Yeqin Guan)
Artilce link：https://doi.org/10.1016/j.checat.2021.08.006
