Fully Reversible High-Capacity Ammonia Storage in a Series of Phase-Transformable Molecular Nickel Thiocarboxylates
Year: 2026
Type: preprint
Abstract: Ammonia (NH 3 ) is an indispensable chemical commodity in modern society, but its nature as a toxic and corrosive gas makes its storage and transport difficult. Here, we report non-porous molecular nickel thiobenzoate [Ni 2 (PhCOS) 4 ] and derivatives, as a distinct class of phase-transformable adsorbents for reversible and high-density ammonia storage in ambient conditions. Despite lacking intrinsic porosity, [Ni 2 (PhCOS) 4 ] presented excellent sorption capacity of 23.5 mmol/g (effective reversible capacity: 22.0 mmol/g) at 298 K and 1 bar. The multi-sigmoidal adsorption profile, arising from solid-state chemical transformation into well-defined compounds of formulas {Ni 2 (PhCOS) 4 (NH 3 ) n } (n = 1, 8 and 16), provides a large pressure-swing working capacity (11.4 mmol/g between 0.1 and 1.0 bar) and enables complete, energy-efficient regeneration under remarkably mild conditions (60–80 °C). The transformation was associated with drastic changes in the coordination environment of Ni centers yet was fast and fully reversible. Phase transformation-induced self-fragmentation generates hierarchical diffusion pathways, driving rapid kinetics (50% uptake in 95 s). Furthermore, the complex demonstrates outstanding ambient moisture tolerance, 10-cycle durability, scalable one-pot synthesis exceeding 60 g (81% yield), and practical cartridge-level storage (+36wt% mass increase), demonstrating dynamic molecular complexes as a practical platform for gas management.
Source: ChemRxiv
Institution: Kyushu University
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
SDG: Climate action
Open Access status: green
Awards: Creation and functionalization of bio-composite systems using metal-organic polyhedra and enzymes, 無加湿条件で働く極性イオン伝導体の開発, Design and systematic synthesis of novel metal-organic polyhedra for controlled integration with enzymes, Novel functional metal-organic structures (M-MOFs) incorporating metal chains, 伝導イオンと極性骨格の強相関機能の実現と機構解明, G7756371366
OpenAlex ID: W7213986411