Charging a Liquid Organic Hydrogen Carrier System with H-2/CO2 Gas Mixtures

Liquid Organic Hydrogen Carrier (LOHC) systems have attracted growing attention in recent years as efficient way to store and transport hydrogen in the existing infrastructures for liquid fuels. This contribution highlights the additional feature that hydrogenation of the LOHC compound dibenzyltoluene with technical relevant H-2/CO2 gas mixtures (up to 30% CO2) gives access to hydrogen purification and hydrogen storage in one single process step. Alumina supported Rh and Pd catalysts proved to be especially suitable for this task. The rhodium catalysts enabled efficient aromatics hydrogenation in the temperature range of 120 degrees C to 150 degrees C with moderate methane formation (CH4/CO2<0.1 at 150 degrees C). The palladium catalyst showed the lowest selectivity to methane formation (CH4/CO2<0.1 at 270 degrees C) and promising hydrogenation activity at temperatures above 200 degrees C even in the presence of CO and CO2.