A facile synthesis of monodisperse cobalt–ruthenium alloy nanoparticles as catalysts for the dehydrogenation of morpholine borane and the hydrogenation of various organic compounds

Abstract

Herein we report a novel wet-chemical protocol for the composition-controlled synthesis of monodisperse cobalt–ruthenium (CoRu) alloy NPs and their catalysis in the hydrolytic dehydrogenation of morpholine borane (MB) for chemical hydrogen storage and the hydrogenation of various organic compounds using MB as a hydrogen source. Monodisperse CoRu NPs with an average particle size of 1.7 ± 0.6 nm at three different alloy compositions were prepared by the presented novel protocol that comprises the reduction of in situ formed ruthenium(III) oleate complex with dicobalt octacarbonyl (Co₂(CO)₈) in the presence of oleylamine (OAm). Next, as-synthesized CoRu alloy NPs were supported on carbon black (VC) and reduced graphene oxide (rGO) to study their catalysis in the dehydrogenation of MB and the transfer hydrogenation of various organic compouns bearing unsaturated functional groups (nitro, nitrile and carbonyl) using MB as a hydrogen source, respectively. VC–CoRu nanocatalysts exhibited a higher catalytic activity in hydrogen generation from the hydrolysis of MB with an initial turnover frequency (TOF) of 95 mol H₂*(mol (Co + Ru) min)⁻¹ while rGO–CoRu nanocatalysts showed better catalytic performance in the transfer hydrogenation reactions. All tested unsatured organic compounds (30 examples in total) are converted into corresponding hydrogenated products with the yields reaching up to 99% under mild conditions.