Carbon supports for the catalytic dehydrogenation of liquid organic hydrides as hydrogen storage and delivery system

Abstract

The use of liquid organic hydrides as hydrogen carriers is a promising storage and delivery system due to the advantages of using liquid-based infrastructures and its economic feasibility compared to other conventional systems. The reversible dehydrogenation/hydrogenation of liquid organic hydrides is a key point for the development of highly performance reactors. In this study different carbon materials have been investigated as platinum supports, including carbon nanofibers, carbon black, carbon xerogel, activated carbon and ordered mesoporous carbon. To individuate the effect of the carbon support on the catalytic activity, platinum particles were synthesized by a microemulsion procedure. The analysis of the hydrogen evolution curves indicate that the support BET surface area plays a very important role on the initial catalytic activity, obtaining a maximum rate of 220 mmol gPt -1 min-1 when using an ordered mesoporous carbon with a surface area of 930 m2 g-1. Nevertheless, the analysis of catalytic activity at prolonged duration indicates a better behavior towards deactivation for supports characterized by wide pores and low graphitization degree like carbon black or carbon xerogel, despite their lower initial dehydrogenation rate (100-140 mmol gPt -1 min-1). The ultimate use in the dehydrogenation reactor as well as the operation conditions will define the best catalyst structure from the point of view of the carbon support.