Chemical Storage of Ammonia through Dynamic Structural Transformation of a Hybrid Perovskite Compound

Toward renewable energy for global leveling, compounds that can store ammonia (NH₃), a carbon-free energy carrier of hydrogen, will be of great value. Here, we report an organic-inorganic halide perovskite compound that can chemically store NH₃ through dynamic structural transformation. Upon NH₃ uptake, a chemical structure change occurs from a one-dimensional columnar structure to a two-dimensional layered structure by addition reaction. NH₃ uptake is estimated to be 10.2 mmol g^-1 at 1 bar and 25 °C. In addition, NH₃ extraction can be performed by a condensation reaction at 50 °C under vacuum. X-ray diffraction analysis reveals that reversible NH₃ uptake/extraction originates from a cation/anion exchange reaction. This structural transformation shows the potential to integrate efficient uptake and extraction in a hybrid perovskite compound through chemical reaction. These findings will pave the way for further exploration of dynamic, reversible, and functionally useful compounds for chemical storage of NH₃.