Advancements in the development of liquid organic hydrogen carrier systems and their applications in the hydrogen economy

The transition towards sustainable and clean energy systems has become a significant concern in the modern world. Hydrogen has the potential to meet the growing energy demands while addressing greenhouse gas emissions. However, one major obstacle in utilizing hydrogen as a fuel is the lack of efficient and cost-effective storage methods. In this regard, liquid organic hydrogen carriers (LOHCs) offer several advantages, including high hydrogen storage capacity, improved safety compared to traditional storage methods, and the ability to transport hydrogen using existing liquid fuels’ infrastructure. This review summarizes advancements in the development of LOHC systems for hydrogen storage, with a focus on the latest and innovative systems such as those based on dehydrogenative coupling reactions, renewable LOHCs from lignocellulosic biomass, and the development of LOHCs from plastic waste recycling. In addition to the material aspect, this contribution also discusses various applications of LOHCs in the broader context of the hydrogen economy, including a recently proposed concept of mixed gas hydrogenation of LOHCs for realizing hydrogen purification and storage in a single process step. By highlighting the main advantages and challenges of each LOHC system and providing future directions in the development of efficient LOHC systems, this review aims to contribute to an extensive understanding and advancement of LOHCs in the evolving hydrogen-based economy.