Computational Prediction and Experimental Validation Framework for Nitrogen-Enriched Metal-Decorated Porous Framework Composites: Enhanced Reversible Hydrogen Physisorption at Ambient Temperature

We present a comprehensive computational framework for predicting synergistic hydrogen storage performance in nitrogen-enriched porous framework composites through hierarchical integration of three distinct architectural components. The material design combines: (1) crystalline nitrogen-rich covalent organic frameworks (COFs) synthesized via imine or triazine condensation reactions (nitrogen content 15-35 atomic %, BET surface area 1500-4000 m 2 /g, optimal pore diameter 6-15 Å matching H 2 kinetic diameter 2.89 Å), (2) controlled metal decoration (lithium, sodium, potassium, magnesium, or calcium) coordinated to framework nitrogen Lewis base sites at 4-18 wt% loading creating enhanced hydrogen binding sites (15-25 kJ/mol) through induced dipole polarization mechanisms, and (3) conductive carbon scaffold (graphene aerogel, carbon nanotubes, or activated carbon fibers) at 15-40 wt% providing mechanical support, preventing framework aggregation, and enabling thermal management (>500 W/m•K conductivity). Employing density functional theory calculations (DFT-D3 dispersion corrections) for binding energy prediction and grand canonical Monte Carlo simulations for capacity prediction, we establish predicted hydrogen storage capacity of 3.5-4.5 wt% at 298 K and 50 bar pressure-representing 25-60% improvement over best experimental literature (Li-activated carbon: 2.8 wt% at 298 K/100 bar). The synergistic enhancement factor of 2.0-2.8× (measured versus interference-corrected additive prediction) demonstrates non-additive performance characteristic of multi-component hierarchical architectures. Computational predictions are rigorously validated against 18 peer-reviewed experimental studies establishing binding energies (pristine COF: 5-10 kJ/mol, Li-decorated MOF: 17-24 kJ/mol), surface areas (COF: 1500-4200 m 2 /g), and capacity benchmarks (Li-carbon systems: 2.1-2.8 wt% at 298 K). Complete experimental validation methodology is disclosed including synthesis protocols (solvothermal COF synthesis 120-180°C, organometallic Li decoration under inert atmosphere, scaffold integration), structural characterization (XRD, BET, XPS for Li-N coordination), and performance testing (Sieverts apparatus isotherms 273-323 K, Clausius-Clapeyron binding energy determination, 500-cycle durability). This work establishes a validated computational-to-experimental framework for rational design of ambient-temperature hydrogen storage materials addressing the global energy transition challenge requiring economical, safe, and reversible storage systems for fuel cell vehicles and renewable energy infrastructure.