Acronynms And Abbreviations

Hydrogen storage materials based on the hydrogen spillover mechanism onto metal-doped nanoporous carbons are studied, in an effort to develop materials that store appreciable hydrogen at ambient temperatures and moderate pressures. We demonstrate that oxidation of the carbon surface can significantly increase the hydrogen uptake of these materials, primarily at low pressure. Trace water present in the system plays a role in the development of active sites, and may further be used as a strategy to increase uptake. Increased surface density of oxygen groups led to a significant enhancement of hydrogen spillover at pressures less than 100 milibar. At 300K, the hydrogen uptake was up to 1.1 wt. % at 100 mbar and increased to 1.4 wt. % at 20 bar. However, only 0.4 wt% of this was desorbable via a pressure reduction at room temperature, and the high low-pressure hydrogen uptake was found only when trace water was present during pretreatment. Although far from DOE hydrogen storage targets, storage at ambient temperature has significant practical advantages oner cryogenic physical adsorbents. The role of trace water in surface modification has significant implications for reproducibility in the field. High-pressure in situ characterization of ideal carbon surfaces in hydrogen suggests re-hybridization is not likely under conditions of practical interest. Advanced characterization is used to probe carbon-hydrogen-metal interactions in a number of systems and new carbon materials have been developed. Correlation the (ii) rehybridized carbon and (iii) chemistry adsorbent with adsorption and energies will result in site specific structure composition relationships. These site specific relationships will be incorporated into a feedback loop involving synthesis to allow for optimization of overall hydrogen uptake to meet DOE storage targets. Although not fully realized, we provided a road map for future work to understand the role of oxygen and water on the formation of active sites. We utilized the high-pressure in situ characterization to demonstrate that theoretically predicted rehybridization does not likely occur under conditions practical for hydrogen storage. The framework for the structure composition relationships with active sites is now