Hydrogen spillover to enhance hydrogen storage - study of the effect of carbon physicochemical properties

Hydrogen storage in carbon materials can be increased by hydrogen spillover from a supported catalyst; a systematic investigation of various carbon supports was used to better understand how hydrogen spillover affects hydrogen storage on carbon materials. Secondary spillover experiments effectively eliminated experimental variables associated with primary spillover, evidenced by materials clustering around the carbon type for a variety of supported catalyst-carbon mixtures. Providing a supported catalyst to act as a hydrogen source enhances the overall hydrogen uptake of a carbon material; for example, simple mixing of carbon nanotubes with supported palladium increased the uptake of the carbons by a factor of three. However, the baseline adsorption of the carbon was the predominant factor in the magnitude of the overall hydrogen uptake, even when hydrogen spillover was active. Three observations illustrated that a dynamic steady-state model is needed for predictive capacity of hydrogen spillover. (C) 2004 Elsevier B.V. All rights reserved.