Evaluation of acetophenone as a novel alcohol-cycloalkane bifunctional liquid organic hydrogen carrier (LOHC)

In this contribution, we propose the couple 1-Cyclohexylethanol/Acetophenone as a new biobased and bifunctional LOHC. This material shows promises for hydrogen storage by DFT modelling, while commercial catalysts were identified to carry out both hydrogenation and dehydrogenation: Ru/Al2O3 was found to catalyse the complete hydrogenation of the LOHC at 115 degrees C in 2 h with 98% selectivity and, for the first time, Pt/C carries out the dehydrogenation at 205 degrees C in 36 h with total conversion but with a limited Degree of Dehydrogenation of 72%. The system was cycled three times during which up to 50% of the total hydrogen capacity was exploited, stable after 3 cycles. Kinetics experiments and DFT modelling of the reactions intermediates show that a system pairing C-O and C-C bonds is prone to degradation, due to side-reactions initiated by the O-moiety and the reversible hydrogenation of the C]O bond during the dehydrogenation step.