Towards an efficient liquid organic hydrogen carrier fuel cell concept

The high temperature required for hydrogen release from Liquid Organic Hydrogen Carrier (LOHC) systems has been considered in the past as the main drawback of this otherwise highly attractive and fully infrastructure-compatible form of chemical hydrogen storage. According to the state-of-the art, the production of electrical energy from LOHC-bound hydrogen, e.g. from perhydro-dibenzyltoluene (H18DBT), requires provision of the dehydrogenation enthalpy (e.g. 65 kJ mol-1(H2) for H18-DBT) at a temperature level of 300 °C followed by purification of the released hydrogen for subsequent fuel cell operation. Here, we demonstrate that a combination of a heterogeneously catalysed transfer hydrogenation from H18-DBT to acetone and fuel cell operation with the resulting 2-propanol as a fuel, allows for an electrification of LOHC-bound hydrogen in high efficiency (> 50 %) and at surprisingly mild conditions (temperatures below 200 °C). Most importantly, our proposed new sequence does not require an external heat input as the transfer hydrogenation from H18-DBT to acetone is almost thermoneutral. In the PEMFC operation with 2-propanol, the endothermal proton release at the anode is compensated by the exothermic formation of water. Ideally the proposed sequence does not form and consume molecular H2 at any point which adds a very appealing safety feature to this way of producing electricity from LOHC-bound hydrogen, e.g. for applications on mobile platforms.Fil: Sievi, Gabriel. Forschungszentrum Jülich; AlemaniaFil: Geburtig, Denise. Universitat Erlangen-Nuremberg; AlemaniaFil: Skeledzic, Tanja. Forschungszentrum Jülich; AlemaniaFil: Bösmann, Andreas. Universitat Erlangen-Nuremberg; AlemaniaFil: Preuster, Patrick. Forschungszentrum Jülich; AlemaniaFil: Brummel, Olaf. Universitat Erlangen-Nuremberg; AlemaniaFil: Waidhas, Fabian. Universitat Erlangen-Nuremberg; AlemaniaFil: Montero, María de Los Angeles. Universidad Nacional del Litoral. Instituto de Química Aplicada del Litoral. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Química Aplicada del Litoral.; ArgentinaFil: Khanipour, Peyman. Forschungszentrum Jülich; AlemaniaFil: Katsounaros, Ioannis. Forschungszentrum Jülich; AlemaniaFil: Libuda, Jörg. Universitat Erlangen-Nuremberg; AlemaniaFil: Mayrhofer, Karl J. J.. Forschungszentrum Jülich; AndorraFil: Wasserscheid, Peter. Universitat Erlangen-Nuremberg; Alemani

Strategies for Low-Temperature Liquid Organic Hydrogen Carrier Dehydrogenation

Liquid Organic Hydrogen Carrier store hydrogen by covalent bonds in a safe and dense manner. Recovery of hydrogen is realized by an endothermal dehydrogenation reaction. Theoretically its heat demand could be covered by waste heat e.g. from a fuel cell. However, to facilitate this, it is crucial to increase the temperature level of PEM fuel cells and lower the temperature level of the dehydrogenation reaction. In this study, strategies for releasing hydrogen from LOHCs at low temperatures are presented and evaluated. Thereby, the focus is on approaches for overcoming limitations by the reaction equilibrium. We see three main options: i) dehydrogenation at low pressure, ii) dilution of hydrogen with an inert gas, and iii) reactive distillation. These options are examined, particularly regarding their suitability for integrating waste heat, e.g. from fuel cells. Low pressure dehydrogenation and reactive distillation show the highest potential for realizing efficient low temperature hydrogen release

Strategies for Low-Temperature Liquid Organic Hydrogen Carrier Dehydrogenation

Liquid Organic Hydrogen Carrier store hydrogen by covalent bonds in a safe and dense manner. Recovery of hydrogen is realized by an endothermal dehydrogenation reaction. Theoretically its heat demand could be covered by waste heat e.g. from a fuel cell. However, to facilitate this, it is crucial to increase the temperature level of PEM fuel cells and lower the temperature level of the dehydrogenation reaction. In this study, strategies for releasing hydrogen from LOHCs at low temperatures are presented and evaluated. Thereby, the focus is on approaches for overcoming limitations by the reaction equilibrium. We see three main options: i) dehydrogenation at low pressure, ii) dilution of hydrogen with an inert gas, and iii) reactive distillation. These options are examined, particularly regarding their suitability for integrating waste heat, e.g. from fuel cells. Low pressure dehydrogenation and reactive distillation show the highest potential for realizing efficient low temperature hydrogen release