Effective catalysts for typical liquid organic hydrogen carrier N-Ethylcarbazole

Hydrogen can play a significant role as a clean energy vector due to its abundance, high gravimetric energy density, and environmental friendliness. However, efficient hydrogen storage remains a bottleneck that poses economic and technological challenges to the current system. Liquid organic hydrogen carriers (LOHCs) have drawn intensive attention for their excellent compatibility with the existing fuel infrastructure. Among the LOHCs under development, N-ethylcarbazole (NEC) is an attractive option mainly due to its ability to undergo hydrogenation and dehydrogenation below 200 degrees C. This review discusses the recent experimental and theoretical progress of catalyst development for hydrogen storage in NEC. The effect of various catalysts, including Ru-, Ni-, Pd-, and Pt-based, on (de) hydrogenation of NEC is discussed. In addition, bidirectional catalysts and catalyst support materials are also discussed. We conclude the review with a brief discussion of the future research directions.