Publication

Abstract : Hydrogen storage under ambient conditions remains a key challenge for sustainable energy deployment. This study employs Density Functional Theory to investigate essential amino acids as renewable and biodegradable molecular frameworks for hydrogen storage, considering both monomeric and dimeric configurations to assess intermolecular cooperativity. Hydrogen adsorption occurs via physisorption, preserving the H–H bond (∼0.73 Å) with binding energies of –0.7 to –1.7 kcal mol−1 per H2, indicating favourable reversibility under ambient conditions. The interactions are governed by weak charge-transfer contributions from heteroatom lone pairs to the σ* orbital of H2, complemented by dispersive forces. Dimerization enhances the number of accessible adsorption sites, thereby improving overall hydrogen uptake without compromising desorption behaviour. Threonine, histidine, phenylalanine, and valine exhibit gravimetric capacities of 13–18 wt%, exceeding the U.S. Department of Energy target (5.5 wt%) and indicating strong potential at the material level for high-capacity hydrogen storage. These findings demonstrate the feasibility of amino acid-based systems as sustainable and tunable hydrogen storage platforms at the molecular level, providing a foundation for further assessment and development of bio-derived adsorbents for practical clean energy applications.