Adsorption study of Hydrogen in Carbon based Materials as measured by Nuclear Magnetic Resonance

Nuclear magnetic resonance is shown to be a sensitive tool to probe hydrogen adsorption. The technique distinguishes between adsorbed H$_{2}$, hydrogen in the gas phase and can discriminate against protons brought in through contaminants. NMR provides a quantitative measurement of the number of molecules adsorbed. An estimate of the adsorption energy can be obtained from the measured isotherm. Adsorption measurements of H$_{2}$ in several materials -- metal organic frameworks, conducting polymers, and doped single walled carbon nanotubes -- are reported. Boron doped SWNTs when loaded with H$_{2}$ produce intriguing $^{1}$Hspectra indicative of adsorption and possibly several adsorption sites