Homogeneously catalysed conversion of aqueous formaldehyde to H2 and carbonate

Small organic molecules provide a promising solution for the requirement to store large amounts of hydrogen in a future hydrogen-based energy system. Herein, we report that diolefin–ruthenium complexes containing the chemically and redox non-innocent ligand trop 2 dad catalyse the production of H 2 from formaldehyde and water in the presence of a base. The process involves the catalytic conversion to carbonate salt using aqueous solutions and is the fastest reported for acceptorless formalin dehydrogenation to date. A mechanism supported by density functional theory calculations postulates protonation of a ruthenium hydride to form a low-valent active species, the reversible uptake of dihydrogen by the ligand and active participation of both the ligand and the metal in substrate activation and dihydrogen bond formation. Aqueous formaldehyde is an attractive hydrogen storage system due to the high weight percentage of hydrogen present. Here the authors report a highly active homogeneous ruthenium catalyst system, allowing hydrogen production from formaldehyde-water under mild conditions.