Topochemical Synthesis of Ca3 CrN3 H Involving a Rotational Structural Transformation for Catalytic Ammonia Synthesis

Yu Cao; Maria A Kirsanova; Masayuki Ochi; Walid Al Maksoud; Tong Zhu; Rohit Rai; Shenghan Gao; Tatsuya Tsumori; Shintaro Kobayashi; Shogo Kawaguchi; Edy Abou-Hamad; Kazuhiko Kuroki; Cédric Tassel; Artem M Abakumov; Yoji Kobayashi; Hiroshi Kageyama

doi:10.1002/anie.202209187

Topochemical Synthesis of Ca₃ CrN₃ H Involving a Rotational Structural Transformation for Catalytic Ammonia Synthesis

Angew Chem Int Ed Engl. 2022 Sep 26;61(39):e202209187. doi: 10.1002/anie.202209187. Epub 2022 Aug 23.

Authors

Affiliations

¹ Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
² Center for Energy Science and Technology, Skolkovo Institute of Science and Technology, Nobel str. 3, 121205, Moscow, Russia.
³ Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan.
⁴ Chemical Science Program, KAUST Catalysis Center, Division of Physical Science and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia.
⁵ Japan Synchrotron Radiation Research Institute, Sayo-cho, Hyogo 679-5198, Japan.
⁶ Imaging and Characterization Department, Core Labs, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia.

PMID: 35929578
DOI: 10.1002/anie.202209187

Abstract

Topochemical reactions have led to great progress in the discovery of new metastable compounds with novel chemical and physical properties. With these reactions, the overall crystal structure of the host material is generally maintained. Here we report a topochemical synthesis of a hexagonal nitride hydride, h-Ca₃ CrN₃ H, by heating an orthorhombic nitride, o-Ca₃ CrN₃ , under hydrogen at 673 K, accompanied by a rotational structural transformation. The hydrogen intercalation modifies the Ca-N rock-salt-like atomic packing in o-Ca₃ CrN₃ to a face-sharing octahedral chain in h-Ca₃ CrN₃ H, mimicking a "hinged tessellation" movement. In addition, the h-Ca₃ CrN₃ H exhibited stable ammonia synthesis activity when used as a catalyst.

Keywords: Ammonia Synthesis Catalysis; Hydrides; Mixed Anions; Nitrides; Topochemistry.

Abstract

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