The efficient storage of hydrogen is the bottleneck in the development of fuel-cell powered vehicles. Currently, technical targets for hydrogen storage capacity have not been met by any existing technology. The European Union has set research needs for hydrogen storage in very high priority in view of the expected benefits of fuel cells in facing the global warming problem. Experimental studies have concluded that a promising method for storing hydrogen is by adsorption in metal-doped porous materials. Physically, in this method, the metal nanoparticles cause dissociation of hydrogen gas and H atoms subsequently migrate to the porous adsorbent. The phenomenon is called spillover and its mechanism is currently not understood. We aim to use a multi-scale modeling approach, consisting of ab-initio DFT calculations, Monte Carlo simulations and macroscopic modeling, in order to: a) Understand the mechanism of spillover and the effects of material properties and operating conditions. b) Quantify the capacity of hydrogen storage by spillover on a variety of metal-doped porous materials, including graphitic materials, carbon nanotubes, carbon foams, graphite-oxide materials, metal-organic frameworks and covalent-organic frameworks) c) Predict materials that would be expected to have high hydrogen storage capacities through the mechanism of spillover.