A review of reversible hydrogenation and dehydrogenation catalysts for liquid organic hydrogen carriers

Hydrogen energy is widely regarded as a green, low-carbon, and efficient secondary energy source with immense potential for future energy systems. As a clean alternative to the traditional fuels, its use could significantly reduce carbon emissions and contribute to a more sustainable energy landscape. However, one of the key challenges in realizing this potential is the safe and efficient storage of hydrogen. Among the various storage technologies, liquid organic hydrogen carriers (LOHCs) have emerged as a promising solution for both on-board and off-board hydrogen storage systems. LOHCs offer notable advantages, including low cost, high hydrogen storage capacity, and storage efficiency. Despite these benefits, LOHC technology faces several obstacles, such as high reaction temperatures, reliance on expensive noble metal catalysts, and the relatively low efficiency of non-precious metal catalysts during hydrogenation and dehydrogenation processes. Consequently, there has been growing interest in developing more efficient and cost-effective catalysts to overcome these limitations. This paper reviews the recent advancements in the catalytic hydrogenation and dehydrogenation of LOHCs, particularly focusing on the role of metal catalysts in enhancing the reversible hydrogenation and release of hydrogen. The insights provided are intended to guide the rational design of next-generation catalysts, which could significantly enhance the performance of hydrogen storage systems and advance hydrogen technology toward broader practical applications.