Reversible hydrogen storage under ambient conditions remains limited by the weak binding of physisorption and the irreversibility of atomic chemisorption. Molecular chemisorption, exemplified by Kubas-type interactions, offers an intermediate binding regime but is rarely realized in porous solids. Here, we report hydrogenase-inspired Ni–Fe biomimetic centers grafted onto in situ functionalized boron nitride nanosheets (BNNs) that reversibly bind molecular H2 under near-ambient conditions. At 298 K and 35 bar, NiFe2-OBNNs reached gravimetric and volumetric capacities of 2. 15 wt. % and 30 g L−1, respectively. Multitemperature isotherms fitted using a trisite Langmuir–Freundlich model yielded an adsorption enthalpy of −25. 6 ± 0. 3 kJ mol–1 and an entropy of −72. 6 ± 0. 9 J mol–1 K–1. These adsorption and thermodynamic trends indicated that metal-specific controls decoupled functional roles, with Fe-rich sites maximizing capacity, Ni-rich sites enhancing reversibility, and mixed Ni–Fe centers exhibiting the optimal balance observed in this study. Moreover, ex situ spectroscopy and diffraction analyses were consistent with a thiolate-bridged (CN) 2 (CO) Fe–Ni motif featuring an open coordination site compatible with side-on dihydrogen (η2-H2) binding. These results provide guiding principles for designing coordination complex-based porous materials for ambient-relevant hydrogen storage.
Tsipoaka et al. (2026) studied this question.