Ammonia adsorption on nanostructured silica materials for hydrogen storage and other applications

Our focus in the present study is to apply high specific surface area silica nanostructured porous materials (about 2200 m2/g, as synthesized, and 600-700 m2/g, after stabilization) to adsorb ammonia (NH3) for hydrogen storage and other chemical and pollution abatement applications. We describe here the synthesis, and characterization of these silica materials, and the adsorption study of N2 and NH3. These materials were obtained with the help of a modification of the Stöber-Fink-Bohn (SFB) method. The main change, made here to the SFB method, was the use of amines, i.e., triethylamine as catalysts instead of ammonium hydroxide. The silica materials have been characterized with the help of SEM and FTIR Spectrometry. The N2 adsorption study was carried out with the help of the Quantachrome-Autosorb-1 and the NH3 adsorption with the Quantachrome-Autosorb-l-C. The amount of hydrogen adsorbed in the form of NH3 in the studied silica samples at: P=760 [Torr] (1.01325 x 10(5) [Pa]), was 2 [wt.%] and the amount of hydrogen stored in the form of NH3 at about: P=7500 [Torr] (10.0 x 10(5) [Pa]), in the studied stabilized silica samples was 11 wt.%, a magnitude higher than the goal figure of 6.5 [wt.%] established by the United States of America, Department of Energy.