Graphene-Supported NiPd Alloy Nanoparticles for Effective Catalysis of Tandem Dehydrogenation of Ammonia Borane and Hydrogenation of Nitro/Nitrile Compounds

摘要

Monodisperse NiPd alloy nanoparticles (NPs) are synthesized and assembled on graphene (G) or other support to provide clean, efficient catalysis of tandem reactions—dehydrogenation of ammonia borane (AB) and hydrogenation of R—NO₂ and/or R—CN to R—NH₂. The tandem reactions proceed quickly and with high efficiency in aqueous methanol solutions at room temperature, and the supported catalyst is readily recovered for re-use, providing a simple, efficient and ‘green’ route to the preparation of many common pharmaceutical, dye or other chemical products. NiPd alloy NPs of 3.4 nanometer size were prepared by co-reduction of nickel(II) acetate and palladium(II) acetlyacetonate by borane-tert-butylamine in oleylamine and deposited on G via a solution phase self-assembly process. The G-NiPd showed composition-dependent catalysis on the tandem reaction with G-Ni₃₀Pd₇₀ being the most active. A variety of R—NO₂ and/or R—CN derivatives (R alkyl or aryl) were reduced selectively into R—NH₂ via G-Ni₃₀Pd₇₀ catalyzed tandem reaction in short (5-30 minute) reaction times with conversion yields reaching up to 100%, demonstrating a new approach to G-NiPd-catalyzed dehydrogenation of AB and hydrogenation of R—NO₂ and R—CN. The G-NiPd NP catalyst is efficient and is reusable; thus the reaction can be performed in an environment-friendly process with short reaction times and high yields.