METHOD AND SYSTEM FOR CHEMICAL STORAGE OF HYDROGEN

• Main Authors: Sponholz, Peter, Sang, Rui, Jackstell, Ralf, Ryabchuk, Pavel, Beller, Matthias, Agapova, Anastasiya, Junge, Henrik
• Format: Patent
• Language: English; French; German
• Published: 15.06.2022
• Subjects: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; COMPOUNDS THEREOF; INORGANIC CHEMISTRY; METALLURGY; NON-METALLIC ELEMENTS; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; THEIR RELEVANT APPARATUS; TRANSPORTING

An aspect of the disclosure relates to a method for a reversible chemical storage of hydrogen. Said method comprises a hydrogenation step in which hydrogen is converted into a C1-C18 alkyl formate as to chemically store the hydrogen, and a (subsequent) dehydrogenation step, in which hydrogen is released from said C1-C18 alkyl formate. The hydrogenation step comprises contacting hydrogen with carbon dioxide and a C1-C18 alcohol in the presence of a hydrogenation catalyst in order to effect the storage of hydrogen by forming a C1-C18 alkyl formate (and water). The dehydrogenation step comprises converting the C1-C18 alkyl formate into hydrogen and carbon dioxide in the presence of water, a base and either a transition-metal hydride catalyst or a precursor of the transition-metal hydride catalyst or a heterogeneous transition-metal catalyst. The transition-metal hydride catalyst comprises a metal-ion selected from the group consisting of Ru, Ir, Mn, Co, Mo, Fe and Rh and at least one hydride ligand coordinated to the metal-ion. Further the transition-metal hydride catalyst comprises a tridentate ligand, or one or two of a bidentate ligand, or a tetradentate PPPP-chelating ligand, which is coordinated to the metal-ion to form the transition-metal hydride catalyst. The tridentate ligand is selected from the group consisting of a PNP-chelating ligand, a PNN-chelating ligand, a PCP-chelating ligand, an NCN-chelating ligand, a PCN-chelating ligand, a PPP-chelating ligand and an NNN-chelating ligand. The a tetradentate PPPP-chelating ligand. Further, the bidentate ligand is selected from a PP-chelating ligand or an NN-chelating ligand.