Synergistic Dual Heteroatom-Engineered Superactivated Carbon Unlocks Record-High Hydrogen Storage via Mg─F Orbital Hybridization

Abstract

Hydrogen storage remains a critical challenge for sustainable energy systems. Here, a surface functionalization strategy is reported through C-Mg─F ternary coordination to engineer biomass-derived porous carbons with exceptional hydrogen storage performance. Using tobacco stems as precursors, the synthesized Mg-F@C material achieves record hydrogen uptake capacities under 77 K of 4.2 wt% at 1 bar and 9.7 wt% at 50 bar, doubling pristine carbon performance. Multiscale analyses reveal adsorption mechanisms dominated by orbital interactions at Mg-active sites, where H2 electron transfer arises from hybridization of Mg 2p and unsaturated 3s orbitals, inducing directional polarization of H2 electron clouds which synergizes with hierarchical porosity (3500 m2 g−1 surface area) to enhance adsorption. Combined photophysical analysis establishes a mechanistic framework linking static electronic configurations to dynamic adsorption processes. The material retains structural integrity under pressure cycling and demonstrates universal applicability across diverse biomass. This work provides a generalizable paradigm for designing high-capacity hydrogen storage materials via orbital-level modulation of porous carbons.